JPH0764048A - Optial device - Google Patents

Abstract

PURPOSE:To enable high-speed wobbling (picture element shifting) and to efficiently attain higher resolution by combining a phase modulation optical element having spacings spacings filled with specific liquid crystals and an optically transparent double refractive medium. CONSTITUTION:This optical device consists of a combination of the phase modulation optical element in which with plural pieces of optically transparent base bodies provided with optically electrodes and oriented films in this order are arranged to face each other apart the prescribed spacings on the electrode and oriented film sides, and in which at least one kind of the liquid crystals selected from among a ferroelectric liquid crystal 3, antiferroelectric liquid crystal and smectic liquid crystal exhibiting an electric gradient effect are injected in the spacings, and the optically transparent double refractive medium 4. By this constitution, the phase of light is changed and the plane of polarization is shifted by the phase modulation optical element and further, incident light is selectively refracted by the double refractive medium 4 and, therefore, the discrete pixels are effectively wobbled. The resolution is thus improved and the image quality is improved as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to liquid crystal, plasma, EL
The present invention relates to an optical device suitable for a display in which pixels are discrete such as (electroluminescence) and a solid-state imaging device represented by a CCD (charge coupled device) in which imaging pixels are discrete.

[0002]

2. Description of the Related Art When a line-sequential scanning pixel display is carried out by the NTSC system or the like for a display device having a discrete pixel array such as a liquid crystal, plasma, EL or the like in a mosaic pattern, a dot pattern, etc. The luminance signal, which should be a signal, is roughly sampled and the position information in the horizontal direction is lost. If the vertical pixel resolution cannot be implemented by the number of scanning lines, the positional resolution of the luminance signal or the like (that is,
Display resolution) was reduced.

For example, a TFT (T
In the hin-Film-Transistor) -TN (Twisted Nematic) liquid crystal viewfinder, in the NTSC system, one frame (that is, one picture displayed by the viewfinder) is an even scan line and an odd scan line. The frame frequency is 30 Hz (that is, the field frequency is 60 Hz). Since the current TFT viewfinder cannot mount 525 scanning lines of the NTSC system, the method of writing the odd field and the even field in the same pixel is adopted. For this reason, the vertical resolution is currently lower than that of the NTSC principle.

Further, due to the large pixel size and the presence of joints of non-display pixel portions such as a black matrix, a mosaic-like screen having a discrete pixel array is conspicuous, and the texture of the screen is deteriorated.

The above phenomenon similarly occurs in the image pickup by the CCD. That is, since the captured image forming the CCD is discrete, the image information of the subject is sampled at the constituent pixel pitch, which lowers the horizontal and vertical spatial resolution.

Therefore, a method has been proposed in which the wobbling technique is adopted to introduce a pixel shifting element and spatially shift the images of the odd field and the even field to improve the vertical resolution. This is also applied in the horizontal direction, and the horizontal resolution can be improved.

However, the wobbling elements that have been proposed so far have a slow response speed and cannot be driven at a video rate, which is not practical and the device configuration conditions are insufficient.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to enable high-speed wobbling (pixel shifting) for a display composed of discrete pixels, a solid-state image pickup device composed of discrete light-receiving pixels, etc. It is an object of the present invention to provide an optical device capable of efficiently achieving the above-described conversion and improving a mosaic-like point-drawing screen or the like into a seamless continuous screen.

Another object of the present invention is, in addition to the above objects, to provide a device having good performance, which enables higher contrast, higher resolution, and suppression of color unevenness at low cost.

[0010]

That is, according to the present invention, a plurality of optically transparent substrates provided with an optically transparent electrode and an alignment film in this order are provided on one side of the electrode and the other of the alignment film. Ferroelectric liquid crystal (FL) is placed facing each other with a predetermined gap.
C), antiferroelectric liquid crystal (AFLC), and smectic liquid crystal (SmA) exhibiting an electroclinic effect.
The present invention relates to an optical device including a combination of a phase modulation optical element in which a kind of liquid crystal (which may be a mixed liquid crystal) is injected into the gap; and an optically transparent birefringent medium.

According to the optical device of the present invention, the phase of the light is changed by the phase modulation optical element to shift the polarization plane, and the incident light is selectively refracted by the birefringent medium. Wobbling can be effectively performed on the pixels, the resolution can be improved, and the image quality can be improved. In particular, it is possible to improve the spatial resolution at the video rate and to improve the mosaic-like pointillistic screen into a seamless continuous screen.

In any of the liquid crystals such as the ferroelectric liquid crystal used for the phase modulation optical element, the direction of the liquid crystal director is easily changed by the action of the electric field, and the response speed is very fast (for example, rising and Both fall time μ
Since it is of the sec order and is much faster than the fall time of twisted nematic liquid crystals), it can be driven at a video rate.

In the present invention, the phase-modulating optical element and the birefringent medium are sequentially arranged in the optical path between the display element and the observation position, which are to be increased in resolution, or between the subject and the image pickup element. A wobbling element may be configured so that the display element or the image pickup element is wobbled one-dimensionally or two-dimensionally.

Further, the birefringent medium is made of a transparent substrate such as a crystal which gives a shift of the optical axis depending on the polarization direction of the incident light, and is arranged so as to have an equivalent uniaxial extraordinary optical axis component in the wobbling direction. Alternatively, the surface facing the substrate through which light is transmitted may not be parallel, and the apparent extraordinary optical axis may be parallel or perpendicular to a plane perpendicular to both planes.

In the present invention, a polarization plane of about 90 is provided in the rear and / or front of the above phase modulation optical element in a wide wavelength range.
It is desirable that a birefringent medium for phase adjustment for rotating the optical axis to shift the optical axis is further arranged.

With this structure, it is possible to widen the wavelength range of the light that rotates the polarization plane by about 90 degrees in high resolution, and to achieve high contrast, high resolution, and suppression of color unevenness. . Also, since the wavelength range in which the wobbling effect is obtained can be expanded to the entire visible light range,
In particular, a single wobbling element can be used to increase the resolution of a display element or an image pickup element composed of three plates of red (R), green (G), and blue (B), and the cost can be reduced. You can

Moreover, the phase compensation by the phase adjustment relaxes the condition of the deviation of the phase difference of the chiral smectic element, that is, the deviation of the gap accuracy, so that the yield is improved. Since the effect of the low-pass filter can be sufficiently exerted in the image pickup device, it is possible to pick up an image with high resolution and reduced moire fringes, color false signals, and the like.

In this case, the birefringent medium for phase adjustment is π
An element made of a liquid crystal material containing an electronic system, an active liquid crystal element sandwiched between at least transparent electrodes, and a polymer film containing a π electron system,
It is desirable that the crosstalk as an integrated amount in the used wavelength range between fields at the time of wobbling be reduced as compared with a wobbling element in which phase adjustment is not performed.

The birefringent medium for phase adjustment is an optically transparent and uniformly oriented smectic liquid crystal (including chiral liquid crystal) element, a nematic liquid crystal element, a main chain type polymer liquid crystal, and a side chain type. Polymer liquid crystal, aromatic polyester film, polycarbonate film, polystyrene or styrene resin film, methacrylic resin film, vinyl resin film, cellulose film, polyamide resin film, and polyphenylene film , A polyphenylene sulfide film, a polysulfone film, an amorphous polyarate film, a polyethersulfone film, a polyetherimide film, a polyetherketone film, a polyamideimide film, and a polyimide film Working with film It may be configured by either Re.

Further, the phase adjusting film constituting the wobbling element for the display element is not directly attached to the phase modulation optical element made of the chiral smectic liquid crystal, and the phase adjusting film constituting the wobbling element for the image pickup element. It is preferable that the film and the polarizing plate are not directly attached to the phase modulation optical element made of chiral smectic liquid crystal.

The polarization plane of the birefringent medium for phase adjustment and phase adjustment of the phase modulation optical element made of chiral smectic liquid crystal is rotated so that the plane of polarization is rotated about 90 degrees in a wide wavelength range to minimize wobbling crosstalk. Phase difference, further the axis of the incident polarization, the slow axis of the phase modulation optical element, the slow axis of the birefringent medium for phase adjustment, the direction of the extraordinary optical axis of the birefringent medium for optical axis shift respectively It can be adjusted.

The orientation treatment direction of the phase modulation optical element made of chiral smectic liquid crystal may be parallel or perpendicular to the pixel shift direction, and the orientation treatment may be performed by rubbing or vacuum deposition.

Further, the phase difference at 632.8 nm of the phase modulation optical element made of chiral smectic liquid crystal is 160 nm to 380 n.
m, and the birefringent medium for phase adjustment is 160 nm to 380 n
It shows the retardation of m and has the same phase difference as the phase difference at 632.8 nm of the phase modulation optical element made of chiral smectic liquid crystal, and it has one of two switching states of the liquid crystal director of the phase modulation optical element. It is desirable that the slow axis of the birefringent medium for phase adjustment be substantially orthogonal to the slow axis.

Further, a liquid crystal display element such as a twisted nematic liquid crystal, a ferroelectric liquid crystal or an antiferroelectric liquid crystal, in which a display element or an image pickup element to be made to have a high resolution is composed of discrete pixels, and a self-luminous light emitting diode or the like Type display element or CCD
And so on.

When the light from the display element or the subject to be high-resolution is not polarized, it is preferable to arrange an element for giving polarization in the optical path between the wobbling element and the display element or the subject. .

The liquid crystal used in the present invention may be a bookshelf, a pseudo bookshelf, or a chiral smectic liquid crystal having a liquid crystal layer structure of chevron structure.

In this case, the pretilt angle of the chiral smectic liquid crystal is preferably 0 to 45 degrees. The apparent cone angle θ of the liquid crystal used is preferably 26 to 64 degrees.

The bisector between the directors in the two switch states of the liquid crystal used in the phase modulation optical element of the present invention is the plane of polarization of the light from the display element (P1) or the line orthogonal thereto (P2). It is desirable that the angle δ formed with) is δ = 22.5 ± 10 degrees when phase adjustment (or compensation) is not performed. Alternatively, between the slow axis of the birefringence having a large absolute value and P1 or P2 among the switch states after the phase compensation in the two switch states of the liquid crystal in the phase modulation (or compensation) phase modulation optical element. The bisector of
The angle δ1 of the light from the display element with the plane of polarization (P1) or the line (P2) orthogonal thereto is preferably in the range of δ1 = 22.5 ± 10 degrees.

When the liquid crystal display or the image pickup device as a display device to be made high resolution is a single plate having red, green and blue trio pixels as one picture element, 632.8 nm
It is recommended that the phase difference measured using the above light source is in the range of 130 nm to 370 nm.

Further, when the liquid crystal display or the image pickup device as the display device for which the resolution is to be increased is three plates, the upper limit of the wavelength range of the transmittance characteristic of each filter to be combined is λ.
_{If Max} and the lower limit are λ _Min , the allowable phase difference is in the range of λ _Max / 2 to λ _Min / 2, red as the light source,
Green, in the case of using the light emission of the blue phosphor, when each of the effective phase difference range in which the center wavelength and λ _C (λ _C -10
It is preferable that it is in the range of 0) / 2 to (λ _C +100) / 2 (however, the unit of each phase difference is nm).

When an image pickup device is combined, 632.8 nm when the image pickup wavelength includes infrared light (wavelength 700 to 1200 nm)
It is recommended that the phase difference measured using this light source is in the range of 350 nm to 600 nm.

The phase modulation optical element can be driven by using a bipolar applied voltage such as rectangular wave driving or pulse driving.

In this case, at the time of wobbling, the response time of the rise and fall of the drive voltage is 1/3 or less of the field time, and the ratio of the rise time and the fall time does not exceed twice each other. Is desirable.

With respect to the length component in the wobbling direction, the pixel aperture (pixel aperture for a monochrome screen or three plates, and one pixel trio for red, green, and blue for a single plate).
Is L _A and the pixel pitch is L _P , the pixel shift amount L
_{Is, Min (L P -L A,} L A / 2) ≦ L ≦ Max (L A,
L _P -L _A / 2) (where, Min (x, y), Max (x, y) , respectively, x, smaller value among the y, a function that gives a higher value.) Good to the .

Further, a display element having the number of horizontal scanning lines N and N divisions to 1 divisions (preferably N divisions to 3 divisions, and further N / 2 divisions or (N + 1) / 2) in the vertical direction of the screen of this display element.
Less than or equal to division and more than or equal to 3 is preferable. It is preferable that the phase modulation optical element having the above-mentioned drive electrode is combined.

In this case, the distance between the divided electrodes is preferably longer than the liquid crystal cell gap (further, shorter than the non-display portion such as the black matrix portion).

At the time of wobbling, the drive of the display element and the drive of the phase modulation optical element are synchronized with the detected video vertical synchronization signal as a reference, and the time for one field is divided by the required number of electrodes, and each channel of the phase modulation optical element is divided. It is possible to drive by sequentially giving a time delay in the field.

Further, with the synchronization signal as a reference, the driving of the image pickup device and the driving of the phase modulation optical device are synchronized, images are taken in each field, and data can be transferred to form one frame.

In the optical device of the present invention, the birefringent medium for shifting the optical axis and the phase-modulating optical element are bonded together by an optical adhesive, or the crystal plate as the birefringent medium is provided with a transparent electrode and an orientation. A film can be provided and integrated with the liquid crystal element.

Further, it can be constructed as a direct-viewing type, a reflection type or a projection type display device, or can be used in the wavelength range of visible light.

Further, a wobbling element may be combined with a solid-state image pickup element to form a visible light or infrared light image pickup device.

Further, the wobbling element, the optical low-pass filter and the solid-state image sensor can be combined,
In this case, it is preferable that the quarter-wave plate is arranged in the optical path between the wobbling element and the optical low-pass filter.

[0043]

EXAMPLES Examples of the present invention will be described below.

FIGS. 1 and 2 schematically show an example of an optical device incorporating the wobbling element according to the present invention.

In this example, the present invention is applied to a liquid crystal optical display device 1, in which a liquid crystal display element (LCD) 2 sequentially arranged in the same optical path along a light traveling direction and a phase modulation optical device. Ferroelectric liquid crystal element (FLC) 3 as an element
And a birefringent medium 4 made of a transparent substrate such as a crystal plate. Here, for ease of understanding, each constituent element is shown for a section corresponding to one constituent display pixel 5 of the liquid crystal display element LCD (hereinafter the same).

The pixels 5 of the LCD 2 are composed of a discrete pixel array such as a mosaic as a whole, and the liquid crystal used is TN (twisted nematic) or STN.
(Super twist nematic), SH (super homeotropic), FLC, etc. This LCD
Although not shown, reference numeral 2 has a polarizing plate on the panel itself as is well known, and the output light 6 has a linearly polarized light.

For the linearly polarized light 6, the above F
The wobbling element (picture element shifting element) 7 composed of the LC 3 and the birefringent medium 4 shifts the picture element in the parallel direction or the vertical direction.

For this purpose, one extraordinary optical axis 8 of the FLC element 3 is arranged so as to be parallel or perpendicular to the polarization plane 9 of the display pixel 5, and the equivalent uniaxial optical axis (uniaxial X of the extraordinary optical axis 10 of the transparent substrate 4 having various optical anisotropy)
The projection component on the −Y plane (incident side) is arranged in parallel (Y direction) or perpendicular (X direction) with respect to the polarization plane 9.

The liquid crystal used in the FLC element 3 is capable of high-speed switching at a video rate, and examples thereof include chiral smectic liquid crystal, and the birefringent medium 4 can be a crystal plate or the like. However, as described later, F
Instead of LC, antiferroelectric liquid crystal (AFLC) or smectic liquid crystal exhibiting an electroclinic effect (for example, smectic A) is also effective, and, of course, a birefringent element other than a quartz plate can be used.

Next, the wobbling operation of the display device 1 will be schematically described.

First, as shown in FIG. 1, the ferroelectric liquid crystal element 3
When the switch state of 1 is the state 1, since the polarization plane 9 of the light 6 emitted from the display element 2 side and the extraordinary optical axis 8 of the ferroelectric liquid crystal element 3 are parallel, the transmitted light 11 maintains the polarization plane. The crystal plate 4 having birefringence is irradiated. Since the crystal plate 4 includes the extraordinary optical axis 10 of the crystal in the plane of incident polarization, the light polarized in the Y-axis direction is refracted in the direction in which the extraordinary optical axis 10 of the crystal plate 4 is tilted, and the air layer is again formed. When it goes out to 12, it becomes parallel to the optical axis, and a deviation from the optical axis of the incident light occurs in the Y direction.

On the other hand, as shown in FIG. 2, the ferroelectric liquid crystal element 3
When the switch state of is the state 2, the polarization plane 9 and the extraordinary optical axis 8
Since the light has an angle of about 45 degrees, the transmitted light 11 rotates in the direction of the extraordinary optical axis and becomes linearly polarized light (Y-axis direction) → elliptically polarized light → circularly polarized light → elliptically polarized light → linearly polarized light (X-axis direction). The polarization plane is changed by 90 degrees from the initial state by changing the inside of the ferroelectric liquid crystal element 3, and the crystal plate 4 is irradiated with the polarized plane. In the crystal plate 4, since the extraordinary optical axis 10 of the crystal is not included in the plane of incident polarization, the light 11 is not refracted but maintains the optical axis as it is, and again exits to the air layer as outgoing light 12.

As described above, the optical axis is shifted depending on the presence or absence of refraction by the quartz plate 4 in the switch state of the FLC 3, that is, in the state 1 and the state 2, and the shift of the optical axis can be used as the operation principle of the pixel shift. it can.

Here, the cone angle of the liquid crystal that determines the switch state in the FLC 3 will be described. In the ferroelectric liquid crystal (the same applies to the anti-ferroelectric liquid crystal), the switching behavior of the liquid crystal director due to the application of the electric field is that liquid crystal molecules follow the South-Goldstone mode described in P150 of "Liquid Crystal Dictionary" (published by Baifukan) Move on a virtual cone. Furthermore, smectic A having an electroclinic effect
The liquid crystal (P145 of the same liquid crystal dictionary) has a cone angle unique to each liquid crystal composition similar to the cone angle even when the soft mode described in P119 of the same liquid crystal dictionary is used.

That is, consider a cone model of the liquid crystal 15 sandwiched between the transparent electrodes 13-14 made of ITO (Indium tin oxide in which indium is doped with tin) as shown in FIG. The opening angle of the cone is called the cone angle θr, and the projection of this cone angle on the glass substrate with the transparent electrode is called the apparent cone angle θ. Optically, the apparent cone angle θ may be considered. Since this cone angle shows temperature dependence as shown below, in order to obtain an effective wobbling effect, for example, even if a cone angle of 45 degrees is obtained at 25 ° C., the cone angle is low on the low temperature side due to the environmental temperature. There is a phenomenon that the cone angle is large and the cone angle is small on the high temperature side.

For example, as shown in Table 1 below and FIG. 4, in an antiparallel cell with a SiO obliquely vapor-deposited alignment film using FLC liquid crystal CS-1014 manufactured by Chisso Petrochemical Co., Ltd.
The apparent cone angle is about 45 degrees near ℃, but it is as large as about 51.6 degrees at 0 ℃, and drops to 7 degrees at 55 ℃. Further, as shown in Table 2 and FIG. 5 below, in a similar cell using the FLC liquid crystal ZLI-3774 manufactured by Merck, the apparent cone angle at 25 ° C. is about 45 degrees, but at the low temperature side − It increases to 54.8 degrees at 10 ℃.

[0057]

[0058]

As described above, when the apparent cone angle θ, that is, the angle formed by the extraordinary optical axis 8 of the liquid crystal before and after switching deviates from 45 degrees, the ideal rotation of the polarization plane of 90 degrees as described above can be achieved. However, various problems occur.

Further, in order to examine the effect of the cone angle, 25
CS-2003 (cone angle 60 degrees), CS-2002 (cone angle 64 degrees), and CS-2004 (cone angle 88 degrees) manufactured by Chisso Petrochemical Co., Ltd. can be used as liquid crystals having a large cone angle at ° C. These are all Iso-N ^* -SmC.
^* -A composition showing Cryst. And cone angle 65 ~
80 degree composition is CS-2002 (cone angle 64 degree) and C
Prepared by blending S-2004 (88 degree cone angle).

The cone angle is measured by measuring the angle formed by the liquid crystal directors in the two switch states. Specifically, the extinction position is observed by observing the liquid crystal cell under a polarizing microscope in which the polarizers are orthogonal to each other. It was calculated from the rotation angle of the stage at (the position where it rotates and becomes dark).

Therefore, as a result of earnest efforts, the present inventor has found that the following combination of optical axes is effective.

The apparent cone angle due to the element environmental temperature is
Deviates from 45 degrees (eg 45 + γ degrees: where γ is 45>γ>
-45), in the wobbling operation, if the optical axis of the liquid crystal director in one of the switch states is ideally aligned parallel to or orthogonal to the polarization plane of the display element side, the polarization plane of the transmitted light in this switch state is It does not change. In this case, since the plane of polarization is not rotated, 100% of the light is refracted in the direction of the extraordinary optical axis 10 of the crystal plate 4 as shown in FIG. At this time, there is almost no component on the Z axis.

And 45+ in the other switch state.
Since it is γ degrees, when γ is positive, the polarization plane of the transmitted light is 90 °.
If it rotates by more than 90 degrees and γ is negative, the plane of polarization does not rotate by 90 degrees. When the plane of polarization is completely rotated by 90 degrees, the component on the Z axis becomes almost 100% as shown in Fig. 2.
As shown in, when the rotation of the polarization plane is deviated from the angle of 90 degrees by γ, the component in the Y-axis direction also increases as the polarization component, so that the component shifted in the Y-direction is included in addition to the component on the Z-axis. Like Therefore, in this case, the effect of shifting the pixels, which should have a high resolution, is reduced.

In particular, it has been found that the cause of reducing the effect of increasing the resolution is due to the leakage component at the time of pixel shifting.

Here, the cone angle of the liquid crystal shown in FIG. 6 will be further described. If the LCD cone angle is not 45 degrees,
As shown in FIG. 7, light leakage (that is, crosstalk) occurs between the odd field and the even field. As a result, for example, when the odd field is white and the even field is black, fringes are observed with sufficient contrast if wobbling is completely performed, but if there is a leakage component, white becomes dark and black becomes bright, The contrast decreases.
For example, if the original display element has a contrast of 100: 1, and crosstalk between fields is 10%, 100%
The white level is 90.1%, and the 0% white level (black level) is
It becomes 10.9% and becomes 90.1: 10.9 = 8.27: 1, and the contrast is considerably lowered.

That is, since a contrast of 8: 1 or more is required for practical use as a display, it is important to suppress crosstalk between fields to about 10% or less (only when the contrast is guaranteed, high resolution is required). The effect of is confirmed).

An optical system for evaluating this crosstalk amount is shown in FIG. This optical system includes a polarization microscope (OPTIPHOTO-POL manufactured by Nikon Corporation) 70,
It consists of a visible spectrophotometer (Otsuka Electronics Co., Ltd. 100) 71, a personal computer and a monitor 72.

The light emitted from the halogen light source 73 is a polarizer 74 / F.
The spectrum can be obtained by passing the light through the LC element 7 / analyzer 75, the quartz fiber 76 and the visible spectroscope 71. Here, the polarizer 74 and the analyzer 75 are installed in parallel, and when the polarization plane is not rotated by the FLC 7, 100% of the light that has passed through the polarizer 74 passes through the analyzer 75 and the spectroscope 71 Will be introduced to. However, if the deviation of the FLC molecular director from the Y axis is ζ and ζ is not zero,
The light from the polarizer 74 undergoes rotation of the plane of polarization. If ζ = 45 degrees and the gap is further adjusted, the polarization plane can be rotated by 90 degrees. As a result, it does not pass through the analyzer 75,
The transmittance becomes 0%.

Here, the rotation characteristics of the plane of polarization when the liquid crystal director was rotated corresponding to the change in the cone angle were evaluated. That is, when the transmittance is 0%, sufficient wobbling can be performed, and when the transmittance is 10%, 10% of the incident light leaks to the field component on the opposite side. Therefore, the actual experimental results are shown below.

FIGS. 9 and 10 show changes in the spectrum when ζ is changed. Furthermore, for the wavelength of the minimum transmittance, change the transmittance when ζ is changed to the maximum transmittance of 100%.
When plotted as, it becomes like FIG. 11 (A) or (B).

Here, 0 degrees or less is a mirror image relationship at 0 degrees, and 45 degrees or more is a mirror image relationship at 45 degrees. To secure a contrast of 8 or more (that is, the transmittance is 10% or less,
Or 90% or more), ζ needs to be about ± 10 degrees or less, 36 degrees to 54 degrees.

Theoretically, the transmittance when the polarizer and the analyzer are parallel is expressed by I / I _O = sin ² (2ζ) · cos ² (πΔn · d / λ). Here, λ is the wavelength, Δn is the birefringence, and d is the cell gap. When the transmitted light intensity is calculated with the phase term πΔn · d / λ = π and plotted, it almost corresponds to the actually measured value, but it can be seen that the actually measured value has a looser constraint condition (FIG. 11 (B)). reference).

Further, in order to obtain a contrast of 40 or more by the above method, it is necessary that the transmittance is 1.5% or less,
For that purpose, ζ needs to be about ± 5 degrees or less, 41 degrees to 49 degrees. In other words, converting this by the apparent cone angle, θ is 26 in the range where high resolution can be achieved by wobbling.
It has been found that ~ 64 degrees, more preferably 36-54 degrees are required. It is clear that this is also the case in the other quadrants shown in FIG.

Therefore, as shown in FIG. 13, in order to improve the reduction in resolution (asymmetry) when the pixel is shifted, the bisector 16 of the angle formed by the above two switch states is separated from the display element. Ideally, the angle δ formed with respect to the plane of polarization of light (Y direction) or the line orthogonal to the plane of polarization (X direction) is
It turns out that it is good if the angle is 22.5 degrees.

By arranging the liquid crystal directors 8 in this way, crosstalk occurs in both switch states as shown in FIGS. 14 and 15.
It was found that the crosstalk in each switch state is small, and the sum is averaged and smaller than in the case where crosstalk occurs on only one side, so the effect of higher resolution is not diminished.

Considering the range of the δ axis in the same way as above, when the apparent cone angle θ is 26 degrees or 64 degrees, δ
= 22.5 degrees only, but when the apparent cone angle θ is 45 degrees, the range of δ should be δ = 22.5 ± 10 degrees, more preferably δ = 22.5 ± 5 degrees. .

Here, the range of the cone angle θ, and further, 2
The angle δ formed by the bisector in the switch state with the plane of polarization of the light from the display element or the line orthogonal thereto was clarified from the following wobbling experimental results.

That is, in the study of fixing the shaft on one side, θ = 26 to
In the range of 64 degrees, we were able to increase the resolution from 240 TV lines of the original liquid crystal display element, which should have been increased by the wobbling effect, to 370 TV lines or more. Furthermore, in the range of θ = 36 to 54 degrees, high resolution with little coloring was achieved. As a result of investigating the position of the δ axis in the range of θ = 36 to 54 degrees, it was found that at δ = 22.5 ± 10 degrees, there was almost no coloring and the resolution could be increased to 370 or more. Furthermore, θ = 36-54 degrees, δ = 2
It was visually confirmed that in the range of 2.5 ± 5 degrees, the crosstalk between fields is reduced and the contrast ratio between fields is increased, so that the resolution is further increased to 390 or more.

The resolution evaluation here is performed by inputting a video signal from an NTSC resolution evaluation pattern (video signal pattern generator: Sony's MTSG-1000) and observing the resolution of black and white lines. (Hereinafter the same).

Next, regarding the phase difference, since the liquid crystal itself has wavelength dependency in its birefringence amount, it is difficult to perform matching over the entire wavelength range. The case where the liquid crystal display for increasing the resolution is a single plate of RGB trio pixels (one pixel is formed) (however, in the case of black and white, one pixel = 1 pixel) was examined. The RGB filters used here have main wavelengths of 650 nm (R), 550 nm (G), and 450 n, respectively, as shown in FIG.
It exists in m (B). Here, considering the visual sensitivity to the resolution of the human eye, the sensitivity ratio is R (red): G
Since (green): B (blue) = 3: 6: 1, it is sufficient to give a half-wavelength phase difference to the weighted average wavelength obtained by weighting the sensitivity of these main wavelengths.

That is, the optimum phase difference = 450 nm × 0.1 + 55
It becomes 0 nm × 0.6 + 650 nm × 0.3 = 570 nm, so the half wavelength should be adjusted to 285 nm. The phase shift of the half wavelength is important for effectively rotating the plane of polarization as described later.

Table 3 below shows the results of actually examining the pixel shift using ferroelectric liquid crystal elements having various phase differences.
Shown in. According to this, the effect of high resolution was recognized in the range of the phase difference of 130 nm to 370 nm measured using the 632.8 nm light source (He-Ne laser light). Among these high-resolution cells, with a phase difference of 137 nm or less and a phase difference of more than 350 nm, the screen was heavily colored, making it difficult to use. Therefore, when increasing the resolution of a single plate panel in which RGB are scattered in a mosaic pattern, a 632.8 nm light source (H
Phase difference measured using e-Ne laser light) is 140 nm
The range of to 350 nm is more preferable.

[0084]

[0085]

Further, when the liquid crystal display for high resolution is a three-panel projection type display, a phase difference may be set for each of the R, G, B color filter characteristics. In this case, when the upper limit of the wavelength range of the transmittance characteristic of each filter is λ _Max and the lower limit is λ _Min , the allowable phase difference is preferably in the range of λ _Max / 2 to λ _Min / 2.

When the light emission of the R, G, B phosphors is used as the light source, R, G, B have emission line spectra.
Under this condition, it becomes very narrow. Usually R, G,
In the B filter, the wavelength range of each filter crosses over and has a width of ± 100 nm with respect to the center wavelength λ _C. Therefore, here, a range of ± 100 nm is effective as the wavelength range with respect to the center wavelength of each light source. That is, the effective phase difference range is preferably in the range of (λ _C −100) / 2 to (λ _C +100) / 2 (each unit is nm) when the center wavelength is λ _C.

Next, a switch state of a concrete combination example of each element constituting the liquid crystal optical device according to the present invention is shown.
Shown in 17. The liquid crystal display element 2 to be combined here may be of any type, such as an active matrix TN liquid crystal, an STN liquid crystal display element, a ferroelectric liquid crystal display element, an antiferroelectric liquid crystal display element, or an SH display element. Here, as an example thereof, a combination example with a TN liquid crystal will be shown.

In the normally white TN liquid crystal display device shown in FIG. 18, the light from the light source is transmitted without applying an electric field to the TN liquid crystal. Here, a combination of the backlight 17-polarizing plate 18-TN liquid crystal 2-polarizing plate 19 or reflection plate-polarizing plate 18-TN liquid crystal 2-polarizing plate 19 is used.
Shows the same TN liquid crystal display element as the conventional one.
Needless to say, the TN liquid crystal element 2 and the ferroelectric liquid crystal element 3 are provided with transparent electrodes on both sides thereof.

In this case, as the electric field strength increases, T
The twist of the N liquid crystal 2 is released, and light is gradually leaked through the polarizing plate to realize gradation display, but any transmitted light is polarized by the polarizing plate 19 in front of the ferroelectric liquid crystal element 3 and has the same linear polarization. Therefore, the pixel shifting can be performed according to the above-described operation principle.

In the normally black TN liquid crystal display element shown in FIG. 19, light is transmitted in a state where an electric field is applied to the TN liquid crystal, and the twist of the TN liquid crystal 2 gradually increases as the electric field strength decreases. It returns, it gets darker gradually,
Although gradation display is realized, since any transmitted light becomes the same linearly polarized light by the polarizing plate 19 in front of the ferroelectric liquid crystal element 3, the pixel shifting can be performed according to the above-described operation principle.

As described above, it is clear that the present invention can be applied to any type of liquid crystal display element as long as the light emitted from the display element is substantially linearly polarized light.

Although the above-mentioned example relates to a display element having polarized light, the present invention can of course be applied to a non-polarized display element.

As shown in FIG. 20, when the polarization degree of the light from the display pixel 5 is small, a polarizing plate 19 may be inserted in the optical path connecting the display element 2 and the pixel shifting element 7 in order to make the light polarized. good. The optical arrangement conditions are the same as in the case of the liquid crystal display element described above.

The non-polarizing display 2 that can be used here is a self-luminous display element such as a plasma display or an LED display.

As described above, based on the present invention, a phase modulation element such as a chiral smectic liquid crystal that can be driven at a video rate (ferroelectric liquid crystal, antiferroelectric liquid crystal, or smectic A liquid crystal having an electroclinic effect). ) 3 is used to arrange the wobbling element 7 in the optical path connecting the display such as liquid crystal, plasma, LED, etc., which is composed of discrete pixels, and the retina of the observer, and wobbling (pixel shifting).
The following [1] can be used as the phase modulation element 3 and the following [2] can be used as the birefringent medium.

[1] At least two states exist in the switch state of the ferroelectric liquid crystal, the antiferroelectric liquid crystal or the smectic A liquid crystal having the electroclinic effect, which can be driven at the video rate, and at least two of them are present. A chiral smectic liquid crystal device with an extraordinary optical axis forming an angle of 26 to 64 degrees, which is optically arranged so that the plane of polarization can be rotated. [2] A transparent substrate that shifts the optical axis depending on the polarization direction of incident light, and specifically, (a) is arranged so as to have an equivalent uniaxial extraordinary optical axis component in the wobbling direction. (B) An element in which the substrate-opposing surface through which light is transmitted is not parallel, and the apparent extraordinary optical axis is parallel or perpendicular to a plane perpendicular to both planes.

Next, a specific manufacturing method and operating characteristics of the constituent elements (cells) of the element 3 will be described.

[1] Ferroelectric Liquid Crystal Switching Element The cell structure is as shown in FIG. That is, a transparent electrode (eg, 100 Ω / □ ITO) on the transparent glass substrates 20 and 21.
13 and 14 are provided, and on top of that, Si is used as a liquid crystal alignment film.
The oblique vapor deposition films 22 and 23 of O were formed. In the method of forming the SiO oblique deposition film, the substrate was placed vertically above the SiO deposition source in the vacuum deposition apparatus, and the angle between the vertical line and the substrate normal was set to 85 degrees. After vacuum deposition of SiO at a substrate temperature of 170 ° C,
Firing was performed at 300 ° C. for 1 hour.

The substrate with the alignment film thus produced was assembled so that the alignment treatment directions were anti-parallel on the opposite surfaces, and the glass beads (true thread: diameter) corresponding to the target gap length were used as the spacers. 0.8 to 3.0 μm (manufactured by Catalysis Kasei) 24 was used. Depending on the size of the transparent substrate, the spacer has a sealing material (UV
Curable adhesive (Photorec: Sekisui Chemical Co., Ltd.)
(Manufactured) 25), the gap between the substrates was controlled by, for example, dispersing about 0.3 wt%. If the substrate area is large, 100 pieces of the true glomeruli at an average density on the substrate / mm ²
After spraying, a gap was formed, a liquid crystal injection hole was secured around the cell, and the cell periphery was bonded with the above sealing material.

After that, a ferroelectric liquid crystal (for example, CS-1014 manufactured by Chisso Corporation) was injected under reduced pressure in a state showing fluidity at an isotropic phase temperature or a chiral nematic phase temperature. After injecting the liquid crystal, the liquid crystal was gradually cooled to remove the liquid crystal on the glass substrate around the injection hole and then sealed with an epoxy adhesive to manufacture a ferroelectric liquid crystal element. The ferroelectric liquid crystal used may be Chisso Co., Merck Co., BDH, or a composition comprising the following ferroelectric liquid crystal compound or a non-chiral liquid crystal containing them, but the limitation is not limited thereto. In addition, the phase sequence is not limited, and what is necessary is to take a chiral smectic liquid crystal phase in the operating temperature range.

The liquid crystal layer structure of the chiral smectic liquid crystal element used here has an X-ray structure that has a bookshelf structure in antiparallel, a chevron structure in parallel, or a pseudo bookshelf structure, depending on the combination of the alignment treatment directions. Clarified by analysis.

[0103]

[Chemical 1]

[0104]

[Chemical 2]

[0105]

[Chemical 3]

[0106]

[Chemical 4]

[0107]

[Chemical 5]

Further, other than the chiral smectic liquid crystal, if the switching speed is high, for example, the following antiferroelectric liquid crystal (AFLC) or smectic A phase exhibiting the electroclinic effect can be applied.

<Anti-ferroelectric liquid crystal> The anti-ferroelectric liquid crystal is C
It was discovered by handani et al. in 1988 and is characterized by the following three points. (1) Utilizes switching between an antiferroelectric state and two stable states of three stable states. (2) A clear threshold value characteristic is exhibited, and a high contrast when driven by multiplex can be obtained. (3) Use positive and negative hysteresis alternately,
Since the occurrence of internal polarization is suppressed, the image sticking phenomenon is unlikely to occur.

The characteristics of this antiferroelectric liquid crystal material are:
Unlike ferroelectric liquid crystals, chiral liquid crystals are the majority of the composition (spontaneous polarization is large, almost 10 times that of ferroelectric liquid crystals), and the substituent for the asymmetric carbon is CH.
₃ group, CF ₃ group, compounds having C ₂ H ₅ group is readily indicates the antiferroelectric, the core structure is expanded. For example, there is CS-4000 manufactured by Chisso Corporation.

<Smectic liquid crystal exhibiting electroclinic effect> The electroclinic effect is a phenomenon in which the tilt angle of the orientation vector is induced by an electric field in the smectic A phase composed of chiral molecules when the temperature is constant. . In the smectic A phase, the orientation vector points in the normal direction of the smectic layer and rotates freely around the major axis. However, application of an electric field along the layer inhibits the free rotation, and the polarization P in the electric field direction is Induced.

Assuming that the linear combination of the polarization P and the tilt angle θ is P = kθ, P = (ε⊥ ^* −ε⊥0) ε _O Ε Therefore, θ = (ε⊥ ^* −ε⊥0) ε _O A tilt angle proportional to the applied electric field E occurs, such as Ε / k. Here, ε⊥ ^* and ε⊥0 are the permittivity of the racemate of the optically active substance, and ε _O is the permittivity of vacuum. From this, the larger the difference in the dielectric constants of the racemic chiral liquid crystals, the greater the electroclinic effect.

Adjustment of retardation by birefringence: The birefringence and phase transition temperature of the ferroelectric liquid crystal used in the FLC element are shown in Table 4 below.

[0114]

In the above wobbling operation, in order to rotate the polarization plane of the liquid crystal by 90 degrees, the phase may be shifted by 180 degrees. Birefringence (n _e -n _o), the following relationship exists between the cell gap d and the phase difference [delta]. δ = 2πd (n _e −n _o ) / λ

Here, it is sufficient to set δ = π. For this purpose, the cell gap d should be set to d = λ / 2 (n _e −n _o ). However, in reality, since the angle α (pretilt angle) formed by the liquid crystal molecules with the substrate is not 0 degree, n _e becomes small and the gap length d must be made longer.

Here, the ordinary _{ray no} is independent of the incident angle and is equal to the refractive index n⊥ in the short axis direction of the liquid crystal molecule. In other words, n _o = n
It is ⊥.

Specifically, n _e is a function of the pretilt angle α,

[Equation 1]

D depends on the pretilt angle α as follows. d = λ / 2 [n _e (α) -n _o]

That is, α can be obtained from the type of the alignment film, and the optimum gap d can be calculated based on the above relational expression. Therefore,
The alignment film can be used regardless of the type of inorganic alignment film such as SiO or organic alignment film such as polyimide, polyamide, polyvinyl alcohol (PVA).

Further, when the pretilt angle α is 90 degrees, the gap length d becomes infinite according to the above equation, so
A pretilt angle of ~ 89 degrees is required. However, since it is difficult to control the pretilt angle beyond 45 degrees, a pretilt angle of 0 to 45 degrees is practically preferable.

Table 5 below shows an example of the electro-optical characteristics of an inorganic alignment film (SiO oblique vapor deposition film). Phase difference δ (R
Etardation) was measured using an automatic birefringence meter manufactured by Oak Co., Ltd., and the value of the phase difference exceeded λ / 4.
It was measured by using two wavelengths of [632.8 nm] and a semiconductor laser light source [780 nm].

[0123]

It is understood that each of the FLCs shows a phase difference of about half of the used optical wavelength, and has a specification capable of rotating the polarization plane of incident light by about 90 degrees.

Further, by adjusting the cell gap in this SiO oblique deposition cell, wobbling cells having various phase differences were produced. The results at the measurement wavelength of 632.8 nm are shown in Table 6 below. When these data are plotted, it can be seen that there is an almost linear relationship as shown in FIG. 22, and the phase difference can be set arbitrarily by gap control. These cells were used for the examination of the range of phase difference described above.

[0126]

[0127]

As a driving method for these ferroelectric liquid crystal elements, a conventional general FLC driving method can be applied. In Figure 23, 1
An example of drive waveforms of a frame and two fields is shown.

FIG. 23 (A) shows a pulse drive with a reset pulse, which is a method of maintaining a neutral electrical condition in the field by adding a reset pulse immediately before writing. Hard to be applied. A in addition to FLC
It can also be used for FLC.

FIG. 23B shows pulse driving without a reset pulse, which is a method of maintaining an electrically neutral condition within one frame. It can be used for AFLC as well as FLC.

FIG. 23 (C) shows a method of maintaining an electrical neutral condition in one frame in the case of square wave driving, in which the DC voltage is applied for a longer time than in pulse driving, but the element isolation If it is highly reliable, it is a highly reliable driving method. FL
In addition to C, it can be used for AFLC and electroclinic smectic A.

Fast response of FLC: The switching characteristics according to the above drive waveforms are shown in Table 5 above. Both the rising edge (10-90% T) and the falling edge (90-10% T) show a high-speed response on the order of μsec, which guarantees a sufficient response within one field and is effective at the video rate. The picture shifting effect is achieved for the first time.

Especially in wobbling (picture element shifting),
It is preferable that the response time of rising and falling is 1/3 or less of the field time, and the ratio of rising time and falling time does not exceed twice each other.

In this respect, when a nematic liquid crystal is used,
Even at high speed, the rise time when an electric field is applied is relatively short, but the fall time when off is long, so switching in the field is not sufficient, and an effective pixel shifting effect cannot be obtained. The twisted nematic pixel shift element has a minimum rise / fall time of about 15 msec (room temperature) when the transmittance change is 0 to 90%.
2: 1 line interlace scanning method (1/60 second per field (16.7 ms)) is quite difficult to realize, and if the 4: 1 line interlaced scanning method is applied with the same number of frames,
It is 1/120 seconds (8.3 ms) per field, and it becomes impossible to follow at all. In this respect, the pixel shifting method using the ferroelectric liquid crystal element is effective because its switching time is shorter than that of the TN liquid crystal. By the way, the rise and fall times of the ferroelectric liquid crystal element are in the order of μsec, and even the slowest one is several ms or less.

Table 7 below shows the response times of various liquid crystals for comparison, and the response speed of the liquid crystals usable in the present invention is extremely fast.

[2] Birefringent transparent substrate that shifts the optical axis depending on the polarization direction of incident light (a) Equivalently uniaxial extraordinary optical axis 10 is on the same plane as the Z axis as shown in FIG. An element that is present at and is not parallel to the axis.

For example, the deviation L of the optical axis of the quartz plate is calculated by the following formula. As shown in FIG. 24, the angle formed by the extraordinary optical axis 10 of the birefringent transparent medium 4 and the optical axis of the wobbling optical system is β, and the thickness of the crystal plate 4 is d. Here, the refractive index n _o of the ordinary light and the refractive index n _e of extraordinary light of the quartz plate 4 are n _e = 1.5533
6, n _o = 1.54425. Here, 0.7 inches, 1
L = 24.5 μm to increase the resolution in the vertical direction of an active matrix TN liquid crystal display with 0.3 million pixels
As values giving the deviation of β = 45 degrees, d = 4.17 mm.

[0138]

[Equation 2]

Here, the range of β effective for expressing the deviation L of the optical axis was 10 to 80 degrees. This deviation of the optical axis differs depending on the constituent pixel pitch described later. Further, the following (b) can be applied as a method of shifting the optical axis by using a polarization switch.

(B) A device in which the substrate surface through which light is transmitted is not parallel, and the apparent extraordinary optical axis is parallel or perpendicular to a plane perpendicular to both planes.

A wedge type nematic liquid crystal cell is constructed as shown in FIG. This cell 34 uses polyethylene terephthalate (PET) film 30 as a spacer on both substrates 31, 32.
The space between the substrates is fixed at an angle α, and the liquid crystal 33
Has been injected.

The cell manufactured here was measured by ordinary light per 27 mm,
It was designed so that the deviation L of the optical axis from the extraordinary light would be 30.7 μm.

Nematic liquid crystal used: ZL manufactured by Merck Ltd.
_{I-2008-000 n e = 1.707 n} o = 1.517 ( Note) Merck & Co., Inc. measurements

Alignment treatment direction, alignment direction of liquid crystal, and optical properties: A polyimide rubbing film (Ube U-Varnish) having a small pretilt angle was used as an alignment film in order to maximize birefringence of the liquid crystal. . The pretilt angle is actually about 1 degree or less.

The rubbing was performed in one direction, and the direction was indicated by the arrow 35 in the wedge-shaped cell as shown in FIGS. 26 and 27. In addition, the combination of orientations is parallel orientation in Type 1,
Type 2 has anti-parallel orientation. After assembling the cell, nematic liquid crystal was injected and the periphery was sealed with an adhesive.

Here, if the refractive index is n _i , the angle of the wedge is α rad, and the distance from the cell to the screen is l,
The deviation from the optical axis is D _i . The refractive index n _i is given by the following equation.

[0147]

[Equation 3]

In the calculation here, if l = 27 mm,
D _i = D _e −D _o = 30.7 μm. Also, in fact,
= 6450 mm, the results shown in Table 8 below were obtained.

[0149]

Although the liquid crystal is used as the wedge-shaped optical element in the above, the birefringent medium can be formed by injection molding of a resin having a large birefringence such as polycarbonate or by laminating a film instead of the liquid crystal. The optical axis of the extraordinary light in this case is the same as that of the liquid crystal.

The general polycarbonate molecular structure of a polycarbonate film that can be used as a birefringent medium is as follows.

Bisphenol A type

[Chemical 6]

The polycarbonate resin having the above-mentioned structure was put into a minimax molding machine (type shown by 80 in FIG. 28) to prepare a wedge-shaped polycarbonate plate 81. That is, the polycarbonate resin was melted at about 300 ° C and manually injection-molded at a mold temperature of 60 ° C. It is considered that the mold temperature at the time of molding is lowered, the melt viscosity is increased, and the orientation of the polycarbonate molecules is made sufficient. The relationship between melt viscosity, molecular orientation, and birefringence of polycarbonate has been reported by Nagai et al. ("Melt Viscosity and Flow Birefringence of Polyca
rbonate "J. Appl. Polym. Sci., Vol.44 (1992) pp.1171
-1177).

The die used had a mirror-finished surface of chrome, and the shape of the die was as shown in FIG.
It has dimensions of 15mm x 20mm. The obtained wedge-shaped polycarbonate 81 had an inclination α of 24 degrees, and could give an optical axis shift of 40 μm per 27 mm.

Next, the above-mentioned liquid crystal optical device according to the present invention will be described more specifically.

Driving Method and Operation for Higher Resolution of Liquid Crystal Display Element In the 2: 1 line interlaced scanning method of NTSC, one field (one frame) can be completed in two fields. Then, in the first (odd) field and the second (even) field,
They interpolate with each other with respect to vertical position information,
This is a method of maintaining the resolution by increasing the number of fields per second. However, since the odd field and the even field are overwritten on the same scanning line especially when the number of vertical pixels is small as in a liquid crystal display device, the original resolution is lowered.

Here, the pixel shift is performed in synchronization with the odd field and the even field, and the afterimage effect by high-speed image replacement is applied to increase the vertical resolution. The shift amount of the pixel shift will be described below. Actually, the liquid crystal has dot-sequential or line-sequential scanning and is scanned in time series, but in the description here, they are handled at the same time so that the principle can be easily understood.

In the case of a monochromatic display element, a three-plate type color display element or a color sequential display element:
Since one switching element corresponds to one picture element, simply shift the picture element on the optical axis by half the distance between the centers of gravity (center-to-center distance between constituent display pixels) in the picture element shifting direction of one picture element. Due to the shift in the direction, the resolution is increased, and at the same time, the non-display area (for example, the black matrix) between the pixels becomes inconspicuous. However, the shift need not be exactly half the distance between the centers of gravity of the picture elements.

That is, as shown in FIG. 29, the effective shift amount differs depending on the difference in the aperture size between the black matrix portion and the constituent pixel portion. When the black matrix portion is equal to or larger than the aperture size of the constituent pixels, the shift (a) of half the constituent pixel pitch in the desired direction for higher resolution is optimal, but the tolerance is recognized as the shift of the pixel position. Half of the constituent pixel aperture is required. Further, when the black matrix portion is smaller than the aperture size of the constituent pixels, at least the shift of the length of the black matrix portion is effective (b, c).

With respect to the length component in the pixel shift direction, the length of the black matrix portion is L _B and the aperture of the constituent pixel is L _A.
Then, the pixel pitch becomes L _P = L _A + L _B , and the pixel shift amount L is Min (L _B , L _A / 2) ≦ L ≦ Max (L _P −L _B , L
Represented by _P -L _A / 2).

If this equation is expressed using L _P and L _A , Min (L _P −L _A , L _A / 2) ≦ L ≦ Max (L _A , L
The _P -L _A / 2). Note that Min (x, y), Max in each of the above equations
(x, y) is a function that gives a small value or a large value of x and y, respectively.

If pixel shifting is performed in the vertical direction as in this example, the resolution in the vertical direction is increased as shown in FIG. Similarly, if the pixel shift is performed in the horizontal direction, the resolution in the horizontal direction is increased (FIG. 31). Further, if the pixel shifting is performed in the diagonal direction, the resolution is increased in the vertical and horizontal directions (FIG. 32).

In the case of a color liquid crystal display element having a color filter: In a normal color display element, one pixel is composed of trio of R, G and B color filters. R,
There are in-line arrangements (Fig. 33), delta arrangements (Fig. 34), etc. for G and B arrangements, but the shift amount of the optical axis here is one of the distances between the closest RGB trio areas and the centers of gravity in the pixel shift direction. /
The length should be 2.

The pixel shift direction of such a pixel shift element can improve the resolution in the shifted direction by the two-dimensional pixel shift including not only the vertical direction but also the horizontal direction or the diagonal direction. Furthermore, the pixel shift range is
By setting the constituent pixel aperture L _A for the length component in the pixel shift direction to that of an RGB pixel trio and setting the length of the black matrix portion to L _B , the same conditions as those of the above-mentioned monochromatic display element can be obtained. You can

Range of the number of divisions of the drive electrodes in the picture element shifting operation:
In principle, a pixel shift synchronized with each switching per pixel is required. In this case, in the case of dot-sequential scanning, picture element shifting elements corresponding to the number of pixels like a TFT (Thin Film Transistor) matrix are required. Further, in the case of line-sequential scanning, it is necessary to divide the electrodes by the number of horizontal scanning lines.

Therefore, when the number of horizontal scanning lines of the display element whose resolution is to be increased is N, it is ideal to divide the transparent electrode into 1 / N in the vertical direction during line-sequential scanning. But,
In order to increase the resolution, it is necessary to use picture element shifting elements that are equivalent in cost. Therefore, the present inventor considered that the upper limit of electrode division can be lowered by a human factor to reduce the cost, and conducted the following experiment.

In combination with the above TFT color liquid crystal display element, the timing of switching the ferroelectric liquid crystal element in synchronization with the vertical synchronizing signal was taken. The FLC element on the entire panel was switched without considering the time series data. Even if it went, about 1/4 of the vertical direction of the panel was improved in resolution from 240 TV lines to 370 TV lines.

From the experiment here, it was found that increasing the resolution is effective even in the vertical division up to about 1/4.
That is, in order to increase the resolution, the pixel shift element to be combined with the display element having the horizontal scanning line number N is divided into N in the vertical direction.
One division is sufficient, but N divisions to 3 divisions are preferable in order to increase the resolution of the entire panel. Furthermore, considering the electrode processing accuracy and cost, N / 2 or (N + 1)
It is preferably less than or equal to any integer division of / 2.

Specific example of high resolution of FLC picture element shifting element with 5-divided electrode structure: FIG. 35 shows an example of combination of divided electrodes. This divided electrode is a transparent electrode (I
(TO) 13 and 14 were formed, and the electrode was etched so as to be divided into five parts. Distance between ITO electrodes (etching part) 10μ
m. The distance between the electrodes is required to be larger than the cell gap (and shorter than the non-display portion) in order to prevent dielectric breakdown due to the potential difference between the electrodes, that is, withstand voltage.
Here, the cell gap is set to 1 μm to 3.0 μm. It is easily understood that the combination of the divided electrodes may be such that one side is the common electrode and both sides are the divided electrodes.

Further, a SiO alignment film is used as the alignment film, and the cell assembling method and the liquid crystal injecting method are the same as in the case of the unipolar cell. The liquid crystal alignment direction was set in consideration of the pixel shift direction.

Regarding the sync signal of the picture element shifting element: Interlace scanning moving image (for example, 24 frames per second for movies, 25 frames per second for television)
I'm sending one or thirty images. However, at 24 to 30 sheets per second, the flicker interference is great, and it can not be used at all.
For this reason, one frame is radiated twice each in a movie and 48 frames are repeated every second, and in a television, the number of repetitions per second is increased by using the interlaced scanning method without increasing the transmission bandwidth. The Japanese domestic standard uses the 2: 1 line interlaced scanning method.

That is, as shown in FIG. 36, the scanning started from the point a reaches the point b in the horizontal scanning of N / 2 times, moves to the point c in the vertical retrace line period, and further moves horizontally in the N / 2 times. The scanning reaches point d, and returns to point a again during the vertical baseline period. The period from d to b is called the first (odd) field, and the period from b to d is called the second (even) field. In the 2: 1 line interlace scanning system, one field (one frame) can be completed in two fields. In addition, there are 3: 1 and 5: 1 line interlace scanning systems.

When the line-sequential scanning screen display of the NTSC system or the like is used, the current CRT has an analog type, so there is little problem in its resolution, but liquid crystal, plasma, EL
For a display with discrete pixels, such as, for example, a considerable amount of horizontal position information is lost due to the discrete pixel array, scanning line information is lost, or the position resolution of the luminance signal is reduced ( That is, the resolution of the display is lowered) as described above.

Here, a concrete method for setting the timing of the picture element shifting (wobbling) will be described. TV signal, Figure 37
As shown in, each field is composed of a luminance signal, a vertical synchronizing pulse, a horizontal synchronizing pulse, a color signal, and a color synchronizing pulse. Here, the vertical sync pulse of the odd field (first field) and the even field (second field) is detected, a sync signal is sent from this to the FLC driver, and then a delay is given to each channel in the driver. The drive waveform may be sent to the FLC cell.

Regarding the synchronization of the divided FLC element, the FLC drive circuit and the video signal processing system: FIG. 38 shows the structure of the electrodes, the connection of the drive circuit and the video signal processing system and the synchronization method. That is, by the video signal processing device 40,
The respective sync pulses of the odd field (first field) and the even field (second field) and the RGB signal are supplied to the display element 2, and at the same time, the vertical sync pulse of each field is detected and the sync signal is sent to the FLC driver 41. Then, the drive waveform delayed in each channel in the driver 41 is sent to the FLC cell 3.

The drive waveform was as shown in FIG. 39. The entire ITO side was used as a common electrode and the five-divided electrode side was divided into Ch1 to Ch5 and pulse-driven as shown. That is, the time of one field is divided into five with the detected vertical synchronizing signal as a reference, and each channel is sequentially delayed.
Therefore, it is important that the driving of the TN liquid crystal display element 2 and the driving of the FLC element 3 are synchronized. In addition, a general FLC driving method and a rectangular wave driving can be applied to these driving waveforms.

Further, a specific method of changing the direction of shifting the picture element will be described. A case of increasing the resolution in the vertical direction of the display element 2 (FIG. 40) and a method of increasing the resolution in the vertical and horizontal directions (FIG. 41) are shown. As a result, it was confirmed that the resolution was increased in each intended direction.

In the above 5-division FLC element, a high resolution was examined in consideration of the drive condition, the optical arrangement, and the pixel shift amount. As a result, a panel in a 0.7 inch, 103,000 pixel active matrix TN liquid crystal display was obtained. The resolution has been increased from 240 TV lines to 370 TV lines or more over the entire surface, and the black matrix, which is a non-display area, has become inconspicuous, and a high-resolution and smooth screen has been achieved.

Other Structural Improvements: In the example above,
The chiral smectic liquid crystal element 3 was manufactured by using the transparent glass substrates 20 and 21 as shown in FIG. 42. However, in order to further reduce the cost, volume, and weight, one of the transparent substrates as shown in FIGS. It is also possible to replace 20 with the crystal plate 4, attach the transparent electrode 13 and the alignment film 22 to this crystal plate, and integrate it with the chiral smectic liquid crystal element 3. Then, reflection can be suppressed by matching the refractive index, and the light transmittance can also be improved. In FIG. 44, a reflector 42 is further provided on the display element 2 side,
The display performance is improved.

These high-resolution techniques can be used in any form such as direct-view type, reflection type, and projection type. this house,
45 to 47 show three examples of projection displays.

In the example of FIG. 45, the light from the halogen lamp 17 is led to the display element 2 as a backlight through the cold filter 43, and after the above wobbling process, the lens system is processed.
An image is projected from 44 to screen 45.

FIG. 46 shows a mirror type display, which is a light source.
The light from 17 is passed through the filter 46, separated into predetermined wavelength lights (R, G, B) by the respective dichroic mirrors 47, made incident on the respective wobbling elements from the condenser lens 48, wobbled there, and then again. The combined image is projected on the screen 45.

FIG. 47 shows a prism type display,
It is basically the same as that of FIG. 46 except that the light of each wavelength is combined through the dichroic prism 48.

The above-described high resolution technology is used in the visible light wavelength range because it is applied as a display.

Application to Image Pickup Element The present invention is not limited to the display element 2 described above, but the wobbling element 7 described above is arranged in the optical path connecting the image pickup element such as a CCD composed of discrete pixels and the object. It also applies when.

The image pickup device 71 shown in FIGS. 48 and 49 according to the present invention.
Also in the case of applying to, the various conditions, principles, and explanations described in the above-mentioned display device are preferably adopted in the same manner. In the following, the contents similar to those of the above-described display device will not be particularly described repeatedly, but in comparison therewith, the description will be mainly given to those specific to the imaging device.

When an image pickup device such as a CCD is used, β = 45 in order to increase the resolution of the 1/3 inch CCD in the horizontal direction, the vertical direction, or the horizontal and vertical directions simultaneously.
The amount of pixel shifting was adjusted by adjusting the thickness d of the crystal plate as a degree. Since the horizontal pitch of the 1/3 inch CCD is 6.35 μm and the vertical pitch is 7.4 μm, the pixel shift amount for high resolution in each direction is
It may be set to 3.18 μm or 3.7 μm, which is about ½ of each pitch. Further, in the case of the pixel shifting in the diagonal direction, it is necessary to shift the length of the diagonal line of the rectangle having the horizontal and vertical components as the respective sides. At this time, the length may be 4.88 μm.

For example, in order to give a deviation of L = 3.7 μm, β = 45 degrees and d = 0.63 mm. Here, the range of β effective for expressing the deviation L of the optical axis was 10 to 80 degrees.

When the image pickup device is used, it is arranged in the order of the subject, the polarizer, the FLC element, the birefringent substrate and the image pickup element in the optical path connecting the subject and the image pickup element 4. In this case, the lens system, the iris, and the wavelength limiting filter may be arranged anywhere in the optical path connecting the subject and the image sensor.

As shown in FIGS. 48 and 49, when the switch state of the ferroelectric liquid crystal element 3 is the state 1, the irradiation light component a from the object 50 side passes through the lens 51 and the diaphragm 52, It is polarized by the polarizing plate 19 in the pixel shifting direction. Since the plane of polarization of light and the extraordinary optical axis 8 of the ferroelectric liquid crystal element 3 are parallel, the transmitted light is applied to the quartz plate 4 having birefringence while maintaining the plane of polarization. In the crystal plate 4, since the extraordinary optical axis of the crystal is included in the plane of incident polarization, the light polarized in the Y-axis direction is refracted in the direction in which the extraordinary optical axis of the crystal plate is inclined, and when it goes out to the air layer again. It becomes parallel to the optical axis, and there is a deviation from the optical axis of the incident light.
Each picture element of the D image sensor 53 is irradiated.

On the other hand, when the switching state of the ferroelectric liquid crystal element 3 is the state 2, since the polarization plane and the extraordinary optical axis 8 form an angle of about 45 degrees, the transmitted light rotates in the direction of the extraordinary optical axis. , Linearly polarized light (Y-axis direction) → elliptically polarized light → circularly polarized light → elliptically polarized light → linearly polarized light (X-axis direction), the polarization plane changes 90 degrees from the initial state, and the crystal plate 4 changes. Is irradiated.
Since the crystal plate 4 does not include the extraordinary optical axis of the crystal in the plane of incident polarization, the optical axis is maintained as it is without refraction, goes out to the air layer again, and is irradiated to each pixel of the CCD image pickup device 53. .
That is, the a'portion of the subject is imaged. The shift of the optical axis between the state 1 and the state 2 can be used as the operation principle of the pixel shifting.

The apparent cone angle deviates from 45 degrees due to the element environmental temperature (for example, 45 + γ degrees: where γ is 45> γ).
> -45), in the wobbling operation, when the optical axis of one of the liquid crystal directors in the switch state is ideally aligned parallel to or orthogonal to the polarization plane of the polarizing plate, the polarization plane of the transmitted light does not change in this switch state. . In this case,
Since the plane of polarization is not rotated, 100% of the light is refracted in the direction of the extraordinary optical axis of the crystal plate 4 as shown in FIG. At this time, there are almost no components other than the point a.

In the other switch state, since 45 + γ degrees, the polarization plane of the transmitted light rotates by 90 degrees or more when γ is positive, and the polarization plane rotates by 90 degrees when γ is negative. do not do. When the plane of polarization is completely rotated by 90 degrees, the component a'is almost 100% as shown in FIG. However, as shown in FIG. 50, when the rotation of the polarization plane is deviated from the angle of 90 degrees by γ, the component in the Y-axis direction also increases as the polarization component, so that there is some leakage in the adjacent imaging pixels in the Y direction. Occurs. Therefore, in this case, the effect of shifting the pixels, which should have a high resolution, is slightly reduced.

Therefore, for the same reason as described above with reference to FIG. 13, the bisector of the angle formed by the two switch states forms an angle with the polarization plane of the polarizing plate or a line orthogonal to the polarization plane. Ideally, δ forms an angle of 22.5 degrees. By arranging the liquid crystal directors 8 in this way, crosstalk occurs in both switch states as shown in FIGS. 51 and 52, but the crosstalk in each switch state is small. Moreover, it was found that the sum is less than the crosstalk on only one side, so the effect of higher resolution is not diminished.

Here, the range of θ and the angle δ formed by the bisector in the two-switch state with the plane of polarization of light or the line orthogonal thereto are clarified from the following wobbling experimental results.

That is, in the study of fixing the shaft on one side, θ = 26 to
It was confirmed that the resolution of CCD was increased in the range of 64 degrees due to the wobbling effect. Furthermore, high resolution with less coloring was achieved in the range of θ = 36 to 54 degrees.

Further, as a result of examining the position of the δ axis in the range of θ = 36 to 54 degrees, it was found that there was almost no coloring at δ = 22.5 ± 10 degrees and high resolution could be achieved. Furthermore, θ = 36
In the range of ˜54 degrees and δ = 22.5 ± 5 degrees, crosstalk between fields is reduced, and the contrast ratio between fields is increased, resulting in higher resolution.

Note that the resolution evaluation here is performed by capturing an image of a lattice fringe resolution evaluation panel and converting it to a video signal, and then CR.
It was determined by displaying on a T monitor and observing.

FIG. 53 shows a specific arrangement example. In the case of an optical system such as a video camera or a still video camera, since incident light from the outside world is not substantially polarized, a polarizing plate is inserted between the outside world (subject) and the ferroelectric switching element. The positional relationship with respect to the diaphragm does not matter. Other optical arrangements are subject-lens-aperture-
The order is polarizing plate-ferroelectric switching element-transparent substrate having uniaxial optical anisotropy-imaging element. The image pickup element to be combined here includes a CCD, a MOS type element, and the like.
It doesn't matter what kind.

Since such an image pickup element is a light receiving element, unlike a display element, it is possible to improve the spatial resolution (spatial separation ability) of a subject. Here, since it can be performed by the simultaneous method instead of the sequential method like the display element,
The switching part of the FLC element 3 may act on the entire surface of the CCD element at the same time and does not require spatial electrode division of the phase modulation element 3. That is, for example, the pixels of the CCD image sensor also
If there is no deviation of the optical axis because it is discrete, a for each pixel,
Although there are only b and c position resolutions, the frame is divided, and the information of a, b, and c are first accumulated in the simultaneous method and then transferred.
In the next field, after the position information of a ', b', and c'is accumulated by the pixel shift of the ferroelectric liquid crystal element 3 by the simultaneous method,
By transferring and recombining with the first field, the vertical resolution is doubled.

In order to improve not only the vertical resolution but also the horizontal resolution, one frame must be further divided into three fields and four fields. For this reason, the high speed response of the ferroelectric liquid crystal element is required. is there. Twisted nematic picture element shifting element, transmittance change 0 ~ 90
The minimum rise / fall time is about 15 msec (room temperature) in%, which is quite difficult to achieve even with the NTSC 2: 1 line interlace scanning method (1/60 seconds per field ((16.7 ms)). Furthermore, if the 4: 1 line interlace scanning method is applied with the same number of frames, it is 1/120 seconds (8.3 ms) per field, and it is impossible to follow up at all. It can be seen that the shift method is effective because its switching time is shorter than that of the TN liquid crystal. By the way, the rise and fall times of the ferroelectric liquid crystal element are in the order of μsec, and even the slowest one is several.
It is less than ms.

In the case of a monochrome image pickup device and a three-plate type color image pickup device: one switching element unit corresponds to one picture element, so that the length of the half of the distance between the centers of gravity of one picture element in the resolution improving direction is simply set. The resolution is increased by shifting the optical axis in the direction of improving the resolution. Further, the permissible range is preferably 50% to 150% of the shift length.

In the case of an image sensor having a color filter:
One trio of R, G, B color filters constitutes one picture element. There are delta arrangement, in-line arrangement, etc. as the arrangement method of R, G and B, but the shift amount of the optical axis here is 1 / the distance between the closest R, G and B trio areas in the direction of resolution improvement.
The length should be 2. Further, the permissible range is 50 to 150% of the shift length.

Other Structural Improvements: In the example above,
The ferroelectric liquid crystal element 3 was manufactured by using a substrate different from the quartz plate 4, but in order to further reduce the cost, volume and weight, as shown in FIG. Either a film (all not shown) is attached and a pixel shifting element integrated with the ferroelectric liquid crystal element 3 is arranged through the protective glass substrate 60 on the entire surface of the CCD (A), or it is omitted and the crystal plate is omitted. The side can be adhered and protected (B). In the same figure (C), the CCD 53 and the crystal plate 4 are integrated,
The LC element 3 has the same structure as the above-mentioned example.

A concrete example of mounting these cells on a video camera: Handycam TR-1 (manufactured by Sony Corporation) will be described. First, an infrared cut filter and a low pass filter which can be used therein will be described.

[1] Normal Imaging of Visible Light A semiconductor image pickup device such as a CCD image pickup device has a sensitivity range of
It extends to 380-1200nm. When a normal visible light image is captured, the near infrared light region, which cannot be sensed by the human eye, is captured, which adversely affects the image. Therefore, it is necessary to insert the infrared cut filter 61 between the subject 50 and the CCD 53 as shown in FIG.

Here, an example in which an infrared cut filter (cuts a wavelength of 700 nm or more) 61 is combined with the pixel shift element is shown. Further, since the quartz plate used for the wobbling element is insufficient in cutting high frequency components, an optical low pass filter is required. Therefore, a crystal low-pass filter (a plurality of crystal plates) for 7-point blur that is generally used in a high-quality CCD video camera
It consists of 64. ) Was incorporated (Fig. 55, Fig. 56).

In this low-pass filter, incident light is made into a two-point blur by utilizing its birefringence in one crystal plate, and a two-point image is formed by stacking another crystal plate rotated around the optical axis. It is possible to improve the low-pass filter characteristics by blurring the four-point image into a seven-point image on the third crystal plate.

That is, by blurring the incident light in this way, it is possible to remove a component of image information having a high spatial frequency, and avoid problems such as moire fringes and color false signals. However, in the case of one crystal plate, the high frequency component can be cut or dispersed only in the y direction, but in the above, the high frequency component can be cut or dispersed in both the x and y directions, and the high frequency component of the high frequency component can be retained while maintaining the sensitivity of the low frequency component. It is possible to further eliminate the influence on the image (the generation of a moire fringe pattern or a color false signal in the image output of the formed image).

FIG. 57 shows an implementation example in which such a low-pass filter is not used, and FIG. 58 shows an implementation example in which the low-pass filter is used.
It was shown to. In each case, the picture element shifting element (wobbling element) 7 is provided in front of the CCD 53.

When the low-pass filter 64 is used, the first extraordinary optical axis of the low-pass filter is the polarization during wobbling.
When the angle is 30 to 60 °, the effect of the low pass filter is obtained, but in other cases, the low pass filter characteristic changes in the field. At this time, by inserting a λ / 4 plate (not shown) between the picture element shifting element 7 and the optical low-pass filter, the difference in the low-pass filter characteristics between fields can be reduced and the low-pass filter characteristics can be sufficiently exhibited. Like

FIG. 59 shows a color separation camera system using three CCDs. However, CCD drive circuit,
The wobbling element drive circuit is omitted.

[2] In the case of imaging infrared light By utilizing the near infrared light region of a semiconductor image pickup device such as a CCD image pickup device, it is possible to take an image of only the near infrared light region which cannot be perceived by the human eye. . In this case, it is not necessary to intentionally insert an infrared cut filter.

In this case, to image only infrared light, it is necessary to insert a visible light cut filter (cuts 760 nm or less) between the subject and the CCD. Accordingly, the temperature distribution of the subject can be imaged. Since the imaging wavelength at this time extends to 700 to 1200 nm, the phase difference of the pixel shift element needs to be 350 to 600 nm, which is half the wavelength.

Next, another embodiment of the present invention will be described which uses a birefringent medium (phase compensation medium) for phase adjustment in the above-mentioned embodiments.

According to the examples given below, from 400 nm to 7 nm
By inserting a phase compensation medium that rotates the polarization plane by 90 degrees in the wavelength range of 00 nm into the device, crosstalk in both switch states can be further reduced and higher resolution can be achieved. A concrete example thereof will be shown.

Mounting Example of Phase Compensation Medium FIG. 60 shows a wobbling element in which the phase compensation medium 100 is mounted.
107 and the liquid crystal optical display device 101 are shown.

In FIG. 60A, the ferroelectric liquid crystal (FLC) is used.
The slow axis 108 of the element 3 and the slow axis 118 of the phase compensation medium 100 having the same phase difference as that of the FLC element 3 are substantially orthogonal to each other. As a result, the phase difference generated in the FLC element 3 can be canceled by the phase compensation medium 100 having a phase opposite to that of the phase difference.
Is incident on the birefringent medium 4 for shifting the optical axis without appearing to be parallel to the extraordinary optical axis 10 with the plane of polarization inclined to β, as a result of which the optical axis shifts.

In FIG. 60 (B), the slow axis 10 of the FLC element 3 is
8 is brought into the state 2 by the switch accompanying the application of the electric field to the FLC element 3. As a result, the new slow axis synthesized from the slow axis 108 of the FLC element 3 and the slow axis 118 of the phase compensation medium 100 has an inclination of 45 degrees with respect to the Y axis. Therefore, the plane of polarization is rotated 90 degrees by the combined slow axis,
The plane of polarization becomes parallel to the Z-axis, and since the plane of polarization is incident on the birefringent medium 4 for shifting the optical axis apparently perpendicular to the extraordinary optical axis 10 with the plane of polarization inclined to β, the optical axis does not shift.

Here, the relationship between the optical axes is shown in FIG. 61A, where θ is the apparent cone angle of FLC. In this figure, P
Reference numeral 1 indicates the direction of the plane of polarization parallel to the Y axis or the polarization axis of the polarizing plate. P2 is an axis parallel to the X-axis, and the extraordinary optical axis 10 in which the plane of polarization in the birefringent medium for the optical axis shift is inclined to β
Is orthogonal to. LC1 and LC2 are FLC elements 3
The slow axis 108 of each switch state, PC is the phase compensation medium 10
The slow axis 118 of 0 is shown.

The optical axes are arranged so that the slow axes LC1 and LC2 of the respective switch states of the FLC element are line-symmetrical with respect to the axis of the incident polarization plane P1. Then, by arranging the slow axis PC of the phase compensation medium so as to be substantially orthogonal to one switch state, for example, LC1, the plane of polarization P1 is affected by LC1 of the FLC element to L.
Although rotated on the axis side of C1, it is canceled by the PC having a phase difference substantially the same as LC1, and is returned to the original polarization plane P1. By switching the FLC element by applying an electric field and setting the slow axis to LC2, the polarization plane P1 rotates to the axis side of LC2 and is further influenced by the slow axis PC of the phase compensation medium, and the polarization plane is further increased. The polarization plane P1 is rotated to the axis side of the slow axis PC, and as a result, the polarization plane P1 is rotated to the polarization plane P2 in total of the FLC element and the phase compensation medium. That is, LC2 and PC
The combined slow axis (LC2 + PC) of P1 is exactly π /
The angle is 4.

Further, if the same element as the FLC element 3 used is used as the phase compensation medium 100, the fluctuation of the cone angle due to the temperature change or the like can be further absorbed. This principle diagram is shown in FIG. 61 (B). That is, the second FLC element is used instead of the phase compensation film shown in FIG. The slow axis of the second FLC for phase compensation is set to PC
Let them be LC1 and PCLC2.

First, in the memory state of the second FLC, or when the voltage is applied to PCLC1, the first FLC is set.
The element 3 is switched to LC1 and LC2 by applying an electric field. As a result, the same effect as when the phase compensation film of FIG. 61 (A) is used can be obtained. Further, it can be seen that since the same wavelength dependency of birefringence can be used for the first FLC and the second FLC, the effect of phase compensation is excellent.

Here, when the temperature environment of the element changes, the apparent cone angle changes as shown in FIGS.
In the configuration of FIG. 61 (A), due to the change in the cone angle, light leakage, that is, crosstalk occurs between the odd field and the even field during wobbling. But Figure 61
In (B), since the arrangement of the slow axis of the second FLC element also makes the same temperature change, the angle formed by LC1 and PCLC1 is always π / 2, and the phase difference is canceled. On the other hand, L
Slow axis synthesized from C2 and PCLC1 (LC2 + PC
LC1) always forms an angle of π / 4 with respect to P1 and P2, and the temperature dependence of the phase difference remains slightly, but the crosstalk is reduced.

In this example, the CS-10 is used as the FLC element.
A 14 liquid crystal / SiO diagonal vapor deposition anti-parallel cell was used. The cell gap is 2.1 μm and the phase difference at 632.8 nm is 263.69.
nm. The optical system for evaluating the crosstalk amount is the same as that shown in FIG.

First, FIG. 63 shows the spectrum when the FLC elements are arranged as shown in FIG. 62 and switched by applying an electric field. According to this, in the LC1 state, the polarized light from the polarizer passes through the analyzer without rotation of the plane of polarization. On the other hand, in the LC2 state, the polarized light from the polarizer rotates its polarization plane and is absorbed by the analyzer according to the rotation, and the amount of transmitted light changes. Here, the wavelength component of about 550nm undergoes exactly 90 degree rotation of the plane of polarization.

Further, in order to improve this characteristic, a phase compensation film 100 was arranged as shown in FIG. The optical system of the measurement system is as shown in FIG. In addition, FIG. 65 shows the spectrum of the optical system. According to this, in the switched state of LC1, the polarization plane is not rotated because the phase difference is canceled by the PC, and as a result, as shown in FIG. 65, the analyzer is distributed over almost the entire range from 450 to 700 nm. To Penetrate. On the other hand, in LC2, the plane of polarization is rotated by 90 degrees and the plane of polarization is orthogonal to the analyzer, so it is absorbed, and the transmittance becomes almost zero over almost the entire range from 450 to 700 nm.

Next, using this wobbling element in which the phase has been compensated, a study was made to improve the resolution.

First, the results of no phase compensation are shown in Table 9 below. According to this, although the effect of higher resolution is visually confirmed, the maximum resolution is about 390 lines and the screen is colored due to the gap variation.

[0230]

[0231]

On the other hand, a phase compensation film 100 having a retardation equivalent to that of the FLC element, here a polycarbonate film (for example, manufactured by Nitto Denko Corporation) was selected. For example, for a device with a gap of 2.1 μm, a 260 nm phase compensation film was used.

The results are shown in Table 10 below, in which the coloring of the screen is reduced and the gap range that provides high resolution is expanded.
Furthermore, the crosstalk due to the optical axis shift in the first and second fields is reduced and the contrast in each field is improved, so the resolution can be higher than that without phase compensation and the high resolution up to 450 to 480 TV lines. It was confirmed that

[0234]

[0235]

This result shows that by performing phase compensation on the wobbling element, if a FLC element having a phase difference of 160 to 380 nm measured using a 632.8 nm light source is used, high resolution can be obtained without coloring. It shows what can be achieved. That is, it is understood that the phase compensation film to be combined with the FLC element should be selected to have the same retardation in the range of 160 to 380 nm.

As described above, the phase compensation reduces crosstalk between fields during wobbling and increases the contrast ratio between fields, so that it is understood that the resolution is further improved.

By the phase compensation, for example, as shown in FIG. 61 (C), when the switch state LC1 is canceled by the PC, the magnitude of the birefringence is small, and the direction of the slow axis does not affect much. However, the switch state LC
When it is 2, the position of LC2 + PC (P
1, 45 degrees with respect to P2) has a slow axis, but the slow axis LC2 + PC is synthesized due to the deviation of the orientation direction and the change of the cone angle due to the temperature change.
Deviates from 45 degrees. Since the influence of this shift is so great that the birefringence cannot be ignored, the same study as described above was conducted.

That is, in each of the switch states after phase compensation in the two switch states of the liquid crystal in the phase-compensating optical element which has performed the phase compensation, 2 between the slow axis of birefringence having a large absolute value and P1 or P2. Assuming that the angle between the bisector and the plane of polarization (P1) of the light from the display element or the line (P2) orthogonal thereto is δ1, the position of the δ axis is examined in the range of θ = 36 to 54 degrees. , Δ1 = 22.5 ± 10 degrees, there is no coloring, crosstalk between fields is reduced, and the contrast ratio between fields is increased, resulting in higher resolution.

Here, as the phase compensation film to be used, a colorless and transparent polymer film such as the aromatic polyester series shown below can be used other than polycarbonate.

Usable phase compensation film materials: polystyrene resin, styrene-maleic anhydride copolymer, AS
Resin (acrylonitrile-styrene copolymer); methacrylic resin; vinyl acetate resin, ethylene-vinyl acetate copolymer; cellulose plastics, especially cellulose acetate (Cell-OCOCH ₃ ), cellulose acetate propionate (Cell-OCOCH) _3, -OCOC ₂ H _5), cellulose acetate butyrate _{(Cell-OCOCH 3, -OCOC 3} H 7); polyamide resins represented by nylon; polycarbonate; modified polyphenylene ether; thermoplastic polyester resin (PET: polyethylene terephthalate, PBT: polybutylene terephthalate, PCT: polycyclohexane terephthalate,
PBN: polybutylene naphthalate); polyphenylene sulfide (polythioether sulfone, polythioether ketone, polysulfide sulfone, polysulfide sulfone ketone); polysulfone; amorphous polyarylate; polyethersulfone; polyetherimide; polyetherketone; polyamideimide; Polyimide; further, an aromatic polyester type liquid crystal containing a π-electron type among main chain type high molecular weight liquid crystals; a side chain type high molecular weight liquid crystal, for example, a liquid crystal introduced into a side chain of an acrylate type.

The point common to these is that the molecular structure contains a phenyl group, that is, a π-electron system structure, whereby the wavelength dependence of the refractive index of ordinary light and extraordinary light is similar to that of the FLC element. Therefore, it can be seen that it is preferable for phase compensation in a wide wavelength range. That is, by using a polymer material containing a π-electron system, crosstalk as an integral amount in the used wavelength range between fields at the time of wobbling can be improved as compared with a wobbling element without phase compensation.

The slow axis of these phase compensation films is determined by the stretching operation (inflation method, roll stretching, etc.) in the film formation process (extrusion from the molten state or extrusion from the solution state to the spinning bath), or film formation. It is determined by a method that positively promotes molecular orientation by a subsequent drawing operation (roll drawing, etc.). That is, when electrons easily move in the direction parallel to the molecular chain (polycarbonate, aromatic polyester, etc.), the molecular orientation axis becomes a slow axis.
On the other hand, when electrons easily move in the direction perpendicular to the molecular chain (polystyrene, etc.), the slow axis is in the direction substantially perpendicular to the molecular orientation axis.

The polarizing plate is usually made of T as a protective film.
AC (triacetyl cellulose) is attached, but in this case, since there is no phase difference, there is no improvement in crosstalk. When applying to wobbling, a phase compensator satisfying the above characteristics must be added to the polarizing plate.

Further, as shown by the phantom line in FIG. 60, even if the phase compensation film 100 is replaced between the display element 2 and the FLC element 3, the same effect as above can be obtained. Alternatively,
As will be described later, the phase compensation film 100 is used for the FLC element 3
Between the birefringent medium 4 and the display element 2 and the FLC element 3
It can also be placed on both sides. In this case, it is considered that variability can be given to the phase adjustment.

FIG. 66 shows an embodiment in which the FLC element 3 shown in FIG. 60 and the phase compensation FLC element 110 are combined for phase compensation.

Here, as the combined phase compensation FLC element 110, an element having the same specifications as the FLC element 3 for switching is used. The optical axis is arranged as shown in FIG. 61 (B). At this time, in order to maintain the state 1 of the phase compensation FLC element 110, the FLC memory state or the voltage application state can be used.

Considering the temperature dependence of the cone angle of the CS-1014 liquid crystal shown in FIG. 4, a gentle change in the cone angle from 0 ° C. to 45 ° C. and a rapid change at 45 ° C. or higher are observed. Therefore, when confirmed by the projector method shown in FIG. 79 described later, the environmental temperature of the FLC element is about 23 ° C. at the beginning,
After about 3 minutes, it reached about 45 ° C. Furthermore, when the outside temperature was examined at 30 ° C, the FLC environmental temperature reached 50 ° C.

When a polycarbonate film is used as the phase compensation medium, the resolution is up to 240 TV lines of the original liquid crystal display element as the resolution up to the ambient temperature of the FLC element of 45 ° C.
It was confirmed that the resolution was increased to 450 to 480 TV lines. However, when the FLC element environmental temperature was 50 ° C, the resolution was increased to around 370 to 380 TV lines.

On the other hand, when the FLC switch element and the FLC element 110 having the same specifications are combined as the phase compensation medium, the resolution is up to 240 TV lines of the original liquid crystal display element up to the ambient temperature of the FLC element up to 45 ° C. ~ 480 TV
It was confirmed that the resolution up to the book was increased. Furthermore, when the FLC element environmental temperature is 50 ° C., high resolution of 400 to 430 TV lines has been achieved. That is, it was confirmed that the deterioration of the resolution due to the temperature change can be suppressed.

Even if the phase compensation FLC element 110 is replaced between the display element 2 and the switching FLC element 3, the same effect as above can be obtained.

In the above embodiment, the phase compensation medium 100 or
Although the case where 110 is arranged in front of or behind the FLC element 3 is shown, for example, the case where the phase compensation films are arranged before and after the FLC element 3 at the same time will be described.

As the phase compensation film, the optical axis of each polycarbonate film arranged before and after the FLC element 3 was maintained, and the sum of the phase differences of these films was made substantially the same as the phase difference of the FLC element. Here, the gap is 2.1 μm
Further, a polycarbonate film having a phase difference of 100 nm and 160 nm was used by using the FLC element.

As a result, it was confirmed that the resolution was increased to 450 to 480 TV lines, which was the same as when one phase compensation film was used.

Liquid crystal display elements, especially STN (Super
Twisted Nematic) The phase compensation method used in liquid crystal display devices can also be applied. This is the P. of “Liquid Crystal Display Manufacturing Technology Handbook” (supervised by Takashi Shimada, published by Science Forum Co., Ltd.). As described in 36-37, a STN liquid crystal panel sandwiched between glass substrates is overlaid with a phase compensator, and sandwiched by polarizing plates from both sides to eliminate the screen coloring, which is a drawback of the STN method. It has been resolved. It is more accurate to stack several phase compensating plates with the directions of the optical axes changed, so that a large number of phase compensating plates may be used.

Further, regarding the stacking of the plurality of sheets, P.1 of the above-mentioned "Liquid Crystal Display Manufacturing Technology Handbook" (supervised by Takashi Shimada, published by Science Forum Co., Ltd.)
As described in 84-185, the birefringence (Δn) of the retardation film generally depends on the wavelength λ as shown in the following formula. Δn (λ) = A + B / (λ ² −λ _O ² ) (A and B are constants, λ _O is absorption edge)

Since this wavelength dispersion varies depending on the material of the film, a large number of materials are bonded by combining different materials (for example, polycarbonate and polypropylene, or polycarbonate and polyvinyl alcohol) and adjusting the bonding angle of the slow axis. It is possible to control the wavelength dispersion characteristics of the phase compensation film. This is the phase compensation technique used in the conventional STN.

By applying such a technique to the phase compensation medium in the wobbling element according to the present invention,
It is possible to match the wavelength dispersion characteristic of the birefringence of the phase compensation film with the wavelength dispersion characteristic of the birefringence of the liquid crystal material used for the wobbling element, thereby reducing the crosstalk of the wobbling element.

In the above example, the case where the display element has polarized light is described, but the present invention is also applicable to the case of a non-polarized display element.

That is, in the case of a plasma display, an LED display, etc. (that is, when the degree of polarization of the light from the display pixel is small), a polarizing plate is provided in the optical path connecting the display element and the pixel shifting element for polarization. Just insert. The optical arrangement conditions are the same as in the case of the liquid crystal display element.

Next, the liquid crystal optical device incorporating the above phase compensation medium will be described more specifically.

Driving method in the case of phase compensation As the driving waveform, the driving waveform shown in FIG. 39 can be applied.
The drive waveform shown in FIG. In the wobbling cell, a polyimide alignment film JALS-1524 manufactured by Japan Synthetic Rubber Co., Ltd. was used as the alignment film.

As the method for forming this polyimide alignment film, a polyimide solution was applied by a spin casting method or a gravure printing method, and after firing, an alignment film having a thickness of 80 nm was obtained. The rubbing direction is different from the case without phase compensation, as shown below.

That is, in FIG. 67, the upper surface is on the polyimide alignment film side, but the alignment treatment direction shown by the arrow is the pixel shift direction when the pixel shift is performed in the horizontal or vertical direction with respect to the screen as shown in FIG. 68. Parallel to or perpendicular to.
In addition, in the case of oblique shifting, it is preferable that the screen is parallel to the diagonal direction of the screen.

Further, the cell set is arranged such that the orientation film side is parallel or anti-parallel to the orientation film side, and a gap of about 2 μm is used by using a sealing material in which spacers are dispersed.
And FIG. 68A shows a state in which the upper and lower substrates are joined to assemble a cell, and FIG. 68B shows the relationship between the alignment treatment direction and the pixel shift direction on the upper and lower substrates. Here, the orientation directions after cell assembly are parallel, but they may be antiparallel.

Then, in a cell in which both substrates are opposed to each other in parallel, the pixel shift direction is vertical and the examination is advanced. A phase compensation film manufactured by Nitto Denko Corporation so that it is perpendicular to the switch state of the ferroelectric liquid crystal director on the upper surface of this cell.
The extraordinary optical axes (with a phase difference of 260 nm at a wavelength of 632.5 nm) were aligned and attached with an adhesive material.

Further, this cell was combined with a TN liquid crystal display element 2 as shown in FIG. 69, and confirmation of higher resolution was made. An example of the case of diagonal displacement is also shown in the figure.

Next, an example of the drive waveform used is shown in FIG. This drive waveform is a ferroelectric liquid crystal device,
This is effective when making a twist. In particular, it is effective when the memory characteristics of FLC are weak, or when a sufficient polarization plane rotation effect cannot be obtained due to the twist of the liquid crystal alignment during memory.

That is, this drive waveform repeats at least two positive pulse applications and at least two subsequent negative pulse applications, and the first pulse among the pulses of the same polarity in these pulse applications. The absolute value of
Since the absolute value of the pulse is larger than the absolute value of the pulse, the speed of the first pulse can be increased, and the apparent cone angle can be adjusted by the second pulse. Stability can be improved and deterioration over time can be prevented. Moreover, since the apparent cone angle can be adjusted to 45 ° ± 5 ° by the second pulse, it is possible to suppress the deterioration of the wobbling effect.

In the above-mentioned 5-division FLC element, a high resolution was examined in consideration of the drive conditions, the optical arrangement, and the pixel shift amount. As a result, a panel for an active matrix TN liquid crystal display of 0.7 inch and 103,000 pixels was obtained. The resolution was increased from 240 TV lines to 450 TV lines or more over the entire surface, and the black matrix, which is a non-display area, became inconspicuous and a high resolution and smooth screen was realized.

71 to 74 show various examples of the arrangement of the phase compensation wobbling element and the attachment position of the phase compensation film 100.

In FIG. 71, the bonding position of the phase compensation film 100 with the adhesive material 120 is the ferroelectric liquid crystal element 3 and the crystal plate 4.
72, and FIG. 72 shows a case where the attachment position is between the ferroelectric liquid crystal element 3 and the display element 2. As described above, the attachment position of the phase compensation film 100 is effective regardless of whether it is attached to the front or the rear of the electro-optical element (for example, the FLC element 3) of the smectic liquid crystal.

Regarding the attachment position of the phase compensation film 100, in general, in an electro-optical element of a smectic liquid crystal, since alignment disorder is likely to occur at the time of attaching the phase compensation film, instead of attaching it to the FLC element side, as shown in FIG. Also, as shown in FIG. 74, it may be directly attached to the birefringent medium such as the crystal plate 4 or the display element 2. In this case, the performance and the yield can be improved without causing the disorder of the liquid crystal alignment. It can also be attached to the upper surface of the polarizing plate of the TN liquid crystal display element.

Further, in order to improve the transmittance of the wobbling element, as shown in FIG. 75, between the birefringent medium (quartz plate 4) and the electro-optical element 3, the refractive index of the birefringent medium 4 and the glass substrate is set. It can be attached with an optical adhesive 121 having a refractive index close to. With this structure, the reflection at the air / quartz plate interface was reduced and the transmittance was improved.

Other Structural Improvements: In the above example, the chiral smectic liquid crystal element 3 was manufactured using a transparent glass substrate. However, in order to further reduce the cost, volume and weight, this transparent substrate is used as shown in FIG. Can be integrated with the chiral smectic liquid crystal element 3 by substituting the quartz plate 4 with a transparent electrode and an alignment film, and at the same time, reflection can be suppressed by matching the refractive index and the light transmittance can be improved. .

FIG. 77 is the same as FIG. 76 except that the transparent substrate is the quartz plate 4.
In addition to the above, an example in which the phase compensation medium 100 is attached to the polarizing plate on the TN liquid crystal display element 2 side will be shown.

The above-mentioned high resolution technology can be used in any form such as a direct view type as shown in FIG. 69 and a projection type as shown in FIGS. 78 to 82. Here, FIGS. 78 to 82 are respectively described in FIGS.
47, which corresponds to FIG. 47 and has a phase compensation medium at a predetermined position.
The difference is that 100 is provided, but the operating principle is basically the same.

Application to Imaging Device This phase compensation effect can be applied to the above-mentioned application to the imager. The FLC element used here was one in which the electrodes were not divided. This is because the imaging is performed at the same time, so that it is not necessary to shift in time. Further, here, when a polycarbonate film is used as the phase compensation medium, the optical axis shift can be surely performed in a wide range of wavelength regions, so that the effect of high resolution is improved.

Specific implementation examples 171 are shown in FIGS. 83 to 88, respectively. In either case, high resolution was obtained by effective pixel shifting. Also, Sony Handycam T
An example of mounting on R1 is also shown in FIG. These respective drawings correspond to the described FIGS. 53 to 59, respectively, and are different in that a phase compensation medium 100 is provided at a predetermined position, but the principle of operation is basically the same. .

In the imager of the above-mentioned example, the birefringence anisotropy Δn = n _e −n of the low-pass filter using the quartz plate.
_{Using o} = 0.0091, the moire fringes and color false signals of the CCD image sensor are removed. However, when the light incident on the low-pass filter is linearly polarized light, the effect of the low-pass filter is reduced.

Therefore, as shown in FIG. 89, the quarter-wave plate 130 is provided between the optical axis shifting birefringent medium 4 and the low-pass filter.
To place. This is because if the 1/4 wave plate is arranged with the slow axis at an angle of about 45 degrees for each polarized light from the birefringent medium,
This is because the linearly polarized light becomes circularly polarized light and the effect of the low-pass filter sufficiently functions.

For example, in the case of FIG. 89 (A), the polarized light 12 emitted from the birefringent medium 4 for optical axis shift and parallel to the Y axis passes through the 1/4 wavelength plate 130, and the direction of the slow axis thereof. It becomes a left-handed circularly polarized light that rotates to and enters the quartz crystal low-pass filter. Meanwhile, the figure
In the case of 89 (B), the polarized light 12 emitted from the birefringent medium for optical axis shift and parallel to the X axis is right circularly polarized light that rotates in the direction of the slow axis when passing through the quarter wavelength plate 130. And enters the crystal low-pass filter. As a result, since the crystal low-pass filter is not affected by the polarization, the optical low-pass filter effect can be effectively performed, and as a result, it is possible to capture an image with high resolution and reduced moire fringes, color false signals, and the like. .

Although the embodiments of the present invention have been described above, the above embodiments can be further modified based on the technical idea of the present invention.

For example, the structure, material and shape of each component, the assembling method, and the like, including the above-mentioned liquid crystal element, may be variously changed. The substrate is not limited to the glass plate and may be any other optically transparent material. Various liquid crystals can be adopted.

The object to which the present invention is applied naturally includes not only the optical system such as the above-mentioned display device and image pickup device but also a wobbling element which can be incorporated in the system.

[0286]

As described above, the present invention provides at least one liquid crystal selected from a ferroelectric liquid crystal (FLC), an antiferroelectric liquid crystal (AFLC) and a smectic liquid crystal (SmA) exhibiting an electroclinic effect. Since the optical device is a combination of a phase-modulating optical element injected into the gap between the substrates and an optically transparent birefringent medium, the phase of the light is changed by the phase-modulating optical element. Since the plane of polarization is shifted and the incident light is selectively refracted by the birefringent medium, wobbling can be effectively performed on discrete pixels, the resolution can be improved, and the image quality can be improved. it can.

In any of the liquid crystals such as the ferroelectric liquid crystal used for the phase modulation optical element, the direction of the liquid crystal director is easily changed by the action of the electric field, and the response speed is very fast. Can be sufficiently driven.

[Brief description of drawings]

FIG. 1 is a schematic view of a display device in a state 1 according to an embodiment of the present invention.

FIG. 2 is a schematic view of the same display device in a second state.

FIG. 3 is an explanatory diagram of a cone angle of a ferroelectric liquid crystal (FLC) used in the display device.

FIG. 4 is a graph showing the temperature dependence of the cone angle.

FIG. 5 is a graph showing temperature dependence of the same cone angle in other liquid crystals.

FIG. 6 is a schematic view similar to FIG. 2 for explaining the deviation of the abnormal optical axis of FLC of the display device.

FIG. 7 is a diagram illustrating crosstalk between fields at the time of wobbling (pixel shifting).

FIG. 8 is a schematic diagram of a system for measuring the degree of polarization during wobbling.

FIG. 9 is a graph showing a change in transmission spectrum of liquid crystal.

10 is a graph similar to FIG. 9.

FIG. 11 is a graph showing changes in the transmittance.

FIG. 12 is a diagram for explaining a preferable cone angle of liquid crystal.

FIG. 13 is an explanatory diagram of an improved liquid crystal director direction.

FIG. 14 is a schematic view similar to FIG. 2 in a state 2 of the liquid crystal director.

FIG. 15 is a schematic view similar to FIG. 1 in a state 1 of the liquid crystal director.

FIG. 16 is a transmission spectrum diagram of an RGB filter used in the display device.

FIG. 17 is a schematic view of a specific example of the display device in each switch state.

FIG. 18 is a schematic diagram of a case where a normally white TN liquid crystal display element is used in the display device.

FIG. 19 is a schematic diagram of a case where a normally black TN liquid crystal display element is used in the display device.

FIG. 20 is a schematic diagram of a display device using a display element having a small degree of polarization.

FIG. 21 is a cross-sectional view of a liquid crystal cell as a phase modulation element using a FLC liquid crystal element.

FIG. 22 is a graph showing a change in retardation due to a cell gap of the liquid crystal cell.

FIG. 23 is a waveform diagram showing various driving methods of the same phase modulation element.

FIG. 24 is an explanatory diagram of an optical axis shift due to a birefringent medium.

FIG. 25 is a schematic perspective view of a wedge-shaped cell that serves as a birefringent medium.

FIG. 26 is a schematic diagram illustrating an optical property of the wedge-shaped cell.

FIG. 27 is a schematic diagram illustrating the optical properties of another wedge-shaped cell.

28A and 28B are a plan view and a perspective view showing a molding die of still another birefringent medium and the same medium.

[Fig. 29] Fig. 29 is a schematic diagram showing the shift amount during wobbling (pixel shifting) in each case.

FIG. 30 is an explanatory diagram of a wobbling state.

FIG. 31 is an explanatory diagram of another wobbling state.

FIG. 32 is an explanatory diagram of still another wobbling state.

FIG. 33 is an explanatory diagram of a wobbling state of an RGB in-line array display element.

FIG. 34 is an explanatory diagram of a wobbling state of an RGB delta array display element.

FIG. 35 is a schematic perspective view showing divided electrodes in the phase modulation element.

FIG. 36 is an explanatory diagram of an interlaced scanning method.

[Fig. 37] Fig. 37 is a waveform diagram of a synchronization signal in each field of the television.

[Fig. 38] Fig. 38 is a block diagram showing a connection relationship between respective elements of the display device.

FIG. 39 is a drive waveform diagram of the electrode-divided phase modulation element.

FIG. 40 is a schematic view of a display device using the same element.

FIG. 41 is a schematic view of another display device using the same element.

42 is a cross-sectional view of a structural example of the display device. FIG.

FIG. 43 is a cross-sectional view of another example of the structure.

FIG. 44 is a sectional view of still another example of the structure.

FIG. 45 is a cross-sectional view of a display to which the display device is applied.

FIG. 46 is a cross-sectional view of another application example to a display.

FIG. 47 is a cross-sectional view of still another application example of the display.

[Fig. 48] Fig. 48 is a schematic diagram of a state 1 of an imaging device according to another embodiment of the present invention.

[Fig. 49] Fig. 49 is a schematic diagram of the imaging device in state 2.

50 is a schematic view similar to FIG. 49 for explaining the deviation of the abnormal optical axis of the FLC of the imaging device.

FIG. 51 is a view of the improved liquid crystal director in state 2;
FIG. 50 is a schematic view similar to 49.

52 is a schematic view similar to FIG. 48 in the first state of the liquid crystal director. FIG.

[Fig. 53] Fig. 53 is a schematic diagram of a specific example of the imaging apparatus.

FIG. 54 is a cross-sectional view of a structural example of the imaging device.

FIG. 55 is a schematic diagram of a mounted state of a crystal optical low-pass filter.

[Fig. 56] Fig. 56 is a principle diagram illustrating blurring caused by three crystal filters of the same.

FIG. 57 is a cross-sectional view of a mounting example of the imaging device.

FIG. 58 is a cross-sectional view of another mounting example.

FIG. 59 is a cross-sectional view of still another mounting example.

FIG. 60 is a schematic diagram of a specific example of a display device according to another embodiment of the present invention in each switch state.

FIG. 61 is an explanatory diagram showing a relationship between optical axes of the FLC element and the phase compensation (phase adjustment) film in each state in the same display device.

[Fig. 62] Fig. 62 is an explanatory diagram showing an optical arrangement when there is no phase compensation in the display device.

FIG. 63 is a transmittance spectrum diagram in each state in the same optical arrangement.

64 is an explanatory diagram showing an optical arrangement when phase compensation is performed in the display device. FIG.

FIG. 65 is a transmittance spectrum diagram in each state in the same optical arrangement.

FIG. 66 is a schematic view of a specific example of a display device according to another embodiment of the present invention in each switch state.

67 is each schematic plan view of the substrate showing various alignment treatment directions in the display device. FIG.

[Fig. 68] Fig. 68 is a schematic plan view illustrating a situation when assembling the liquid crystal cell in the display device.

[Fig. 69] Fig. 69 is a schematic diagram showing a method of increasing the resolution in the vertical and / or horizontal directions.

FIG. 70 is a drive waveform diagram illustrating a liquid crystal element drive method.

71 is a cross-sectional view of a structural example of the display device. FIG.

[Fig. 72] Fig. 72 is a cross-sectional view of another structural example.

FIG. 73 is a cross-sectional view of another example of the structure.

FIG. 74 is a cross-sectional view of another structural example of the display device.

FIG. 75 is a cross-sectional view of another structural example of the display device.

FIG. 76 is a cross-sectional view of another structural example of the display device.

[Fig. 77] Fig. 77 is a cross-sectional view of still another structural example of the display device.

FIG. 78 is a cross-sectional view of a display to which the display device is applied.

[Fig. 79] Fig. 79 is a cross-sectional view of another example of application to a display.

[Fig. 80] Fig. 80 is a cross-sectional view of another example of application to a display.

[Fig. 81] Fig. 81 is a cross-sectional view of another example of application to a display.

FIG. 82 is a cross-sectional view of still another application example of the display.

[Fig. 83] Fig. 83 is a schematic diagram of a specific example of an imaging device according to another embodiment of the present invention.

[Fig. 84] Fig. 84 is a cross-sectional view of a structural example of the imaging device.

[Fig. 85] Fig. 85 is a cross-sectional view of another structural example of the imaging device.

[Fig. 86] Fig. 86 is a cross-sectional view of still another example of the structure of the imaging device.

[Fig. 87] Fig. 87 is a cross-sectional view of a mounting example of the imaging device.

FIG. 88 is a cross-sectional view of another mounting example.

FIG. 89 is a schematic diagram of a specific example of an image pickup apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 1, 101 ... (liquid crystal optical) display device 2 ... (liquid crystal) display element 3 ... ferroelectric liquid crystal element 4 ... birefringent medium 5 ... display pixel 7, 107 ... wobbling Element (picture element shifting element) 8, 10 ... Extraordinary optical axis 9 ... Polarization direction 13, 14 ... Transparent electrode 15 ... Liquid crystal 17 ... Light source 18, 19 ... Polarizer 20, 21 ... Transparent substrate 22, 23 ... Alignment film 50 ... Subject 53 ... CCD element 61 ... Infrared cut filter 64 ... Optical low-pass filter 71,171 ... Imaging device 100, 110 ・ ・ ・ Phase compensation (phase adjustment) medium 108, 118 ・ ・ ・ Slow axis

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidehiko Takanashi 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Eriko Matsui 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Yang Eiho 6-735 Kitashinagawa Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Hidefumi Asahi 6-35 Kitashinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (38)

[Claims] 1. A plurality of optically transparent substrates provided with an optically transparent electrode and an alignment film in this order are arranged to face each other at a predetermined gap on the side of the electrode and the alignment film, A phase modulation optical element in which at least one liquid crystal selected from a ferroelectric liquid crystal, an antiferroelectric liquid crystal, and a smectic liquid crystal exhibiting an electroclinic effect is injected into the gap; and an optically transparent birefringence An optical device composed of a combination of a medium and; 2. A phase-modulating optical element and a birefringent medium are sequentially arranged in an optical path between a display element and an observation position which are to be made high in resolution, or an optical path between an object and an image pickup element, thereby forming a wobbling element. The optical device according to claim 1, wherein the optical device is configured so that the display element or the image sensor is wobbled in one dimension or two dimensions. 3. The birefringent medium is composed of a transparent substrate that shifts the optical axis depending on the polarization direction of incident light and is arranged so as to have an equivalent uniaxial extraordinary optical axis component in the wobbling direction. 3. The optical device according to claim 2, wherein the substrate facing surface through which light is transmitted is not parallel, and the apparent extraordinary optical axis is parallel or perpendicular to a plane perpendicular to both planes. 4. The optical device according to claim 2, wherein the wobbling element is driven at a video rate. 5. A birefringent medium for phase adjustment for rotating the polarization plane by about 90 degrees in a wide wavelength range to shift the optical axis is further arranged at the rear and / or front of the phase modulation optical element. The optical device according to any one of claims 1 to 4. 6. A birefringent medium for phase adjustment among an element made of a liquid crystal material containing a π electron system, an active liquid crystal element sandwiched between at least transparent electrodes, and a polymer film containing a π electron system. The optical device according to claim 5, wherein the optical device is configured by any one of them and reduces crosstalk as an integrated amount in a used wavelength range between fields at the time of wobbling as compared with a wobbling element in which phase adjustment is not performed. 7. A birefringent medium for phase adjustment is an optically transparent and uniformly aligned smectic liquid crystal (including chiral liquid crystal) element, a nematic liquid crystal element, a main chain type polymer liquid crystal, and a side surface. Chain polymer liquid crystal, aromatic polyester film, polycarbonate film, polystyrene or styrene resin film, methacrylic resin film, vinyl resin film, cellulose film, polyamide resin film, and polyphenylene -Based film, polyphenylene sulfide-based film,
Polysulfone-based film, an amorphous polyarate film, a polyether sulfone-based film, a polyetherimide-based film, a polyetherketone-based film, a polyamide-imide-based film, and a polyimide-based film The optical device according to claim 6, which is configured. 8. The optical device according to claim 7, wherein the phase adjusting film constituting the wobbling element for the display element is not directly attached to the phase modulation optical element made of chiral smectic liquid crystal. 9. The optical device according to claim 7, wherein the phase adjusting film and the polarizing plate forming the wobbling element for the image pickup element are not directly attached to the phase modulation optical element made of chiral smectic liquid crystal. 10. A polarization plane is rotated about 90 degrees in a wide wavelength range to minimize wobbling crosstalk,
Phase difference of phase-modulating optical element made of chiral smectic liquid crystal and phase difference of birefringent medium for phase adjustment, further, axis of incident polarization, slow axis of the phase-modulating optical element, birefringent medium for phase adjustment 6. The slow axis and the direction of the extraordinary optical axis of the birefringent medium for shifting the optical axis are adjusted, respectively.
10. The optical device according to any one of 9 to 10. 11. The optical device according to claim 10, wherein the orientation processing direction of the phase modulation optical element made of chiral smectic liquid crystal is parallel or perpendicular to the pixel shift direction. 12. The optical device according to claim 11, wherein the alignment treatment is performed by rubbing or vacuum deposition. 13. The optical device according to claim 10, wherein a phase modulation optical element made of a chiral smectic liquid crystal has a phase difference at 632.8 nm of 160 nm to 380 nm. 14. The birefringent medium for phase adjustment is 160 nm to 380 n.
11. The optical device according to claim 10, which exhibits a retardation of m 3 and has the same phase difference as that of a phase modulation optical element made of a chiral smectic liquid crystal at 632.8 nm. 15. A liquid crystal director 2 of a phase modulation optical element.
15. The optical device according to claim 5, wherein the slow axis of the birefringent medium for phase adjustment is substantially orthogonal to the slow axis of either one of the two switching states. . 16. The display device or the image pickup device to be increased in resolution is a liquid crystal display device composed of discrete pixels, a self-luminous display device, or a charge-coupled device. The optical device described in 1. 17. When the light from the display element or the object to be high-resolution is not polarized, an element that imparts polarization is arranged in the optical path between the wobbling element and the display element or the object. The optical device according to any one of claims 2 to 16. 18. The optical device according to claim 1, wherein the liquid crystal used is a bookshelf, a pseudo bookshelf, or a chiral smectic liquid crystal having a liquid crystal layer structure of a chevron structure. 19. The optical device according to claim 18, wherein the pretilt angle of the chiral smectic liquid crystal is 0 to 45 degrees. 20. The apparent cone angle θ of the liquid crystal used is
The optical device according to any one of claims 1 to 19, which is 26 to 64 degrees. 21. A liquid crystal used for a phase modulation optical element.
The angle δ formed by the bisector between the directors in the two switch states with the polarization plane (P1) of the light from the display element or the line (P2) orthogonal thereto is the phase adjustment (or compensation).
Otherwise, δ = 22.5 ± 10 degrees; or, in the phase modulation optical element with phase adjustment (or compensation), the absolute value of each switch state after phase compensation in two switch states of the liquid crystal. Slow biaxial birefringence axis and P1
Or the angle δ formed by the bisector between P2 and the plane of polarization (P1) of the light from the display element or the line (P2) orthogonal thereto.
21. The optical device according to claim 1, wherein 1 is δ1 = 22.5 ± 10 degrees. 22. When the liquid crystal display or the image pickup device as the display device to be made high resolution is a single plate having red, green and blue trio images as one picture element, measurement is performed using a 632.8 nm light source. 22. The optical device according to claim 2, wherein the retardation is in the range of 130 nm to 370 nm. 23. When the liquid crystal display or the image pickup device as the display device to be made high resolution is three plates, the upper limit of the wavelength range of the transmittance characteristic of each filter to be combined is set to λ _Max.
And the lower limit is λ _Min , the allowable phase difference is λ
It is in the range of _Max / 2 to λ _Min / 2, and the light source is red,
Green, in the case of using the light emission of the blue phosphor, when each of the effective phase difference range in which the center wavelength and λ _C (λ _C -10
The optical device according to any one of claims 2 to 21, which is in the range of 0) / 2 to (λ _C +100) / 2 (where the unit of each phase difference is nm). 24. The imaging wavelength includes infrared light (wavelength 700 to 12
00nm), the phase difference measured using a 632.8nm light source is
The optical device according to any one of claims 2 to 23, which has a range of 350 nm to 600 nm. 25. The optical device according to claim 1, wherein the phase modulation optical element is driven by using a bipolar applied voltage. 26. When wobbling, each response time of rising and falling of the driving voltage is 1/3 of the field time.
26. The ratio of the rising time and the falling time does not exceed twice each other.
The optical device according to any one of 1. 27. For the length component in the wobbling direction,
Pixel aperture (Pixel aperture for monochrome screen or 3 plates, 1 for red, green, blue for single plate)
Is L _A and the pixel pitch is L _P , the pixel shift amount L
_{Is, Min (L P -L A,} L A / 2) ≦ L ≦ Max (L A,
L _P -L _A / 2) (where, Min (x, y) and, Max (x, y), respectively, x, to a small value, a function that gives a larger value of the y.), Claims The optical device according to any one of 2 to 26. 28. A combination of a display element having the number of horizontal scanning lines N and a phase modulation optical element having drive electrodes divided into N to 1 in a screen vertical direction of the display element, in combination. The optical device according to any one of items. 29. The optical device according to claim 28, wherein the distance between the split electrodes is longer than the liquid crystal cell gap. 30. The drive of the display element and the drive of the phase modulation optical element are synchronized with the detected video vertical synchronization signal as a reference, the time of one field is divided by the required number of electrodes, and each channel of the phase modulation optical element is divided. A method for sequentially driving with a time delay within the field,
28. The optical device described in 28 or 29. 31. The driving of the image pickup device and the drive of the phase modulation optical device are synchronized with each other based on the synchronization signal, images are taken in each field, and data is transferred to form one frame. The optical device according to any one of 2 to 27. 32. A birefringent medium for shifting an optical axis and a phase modulation optical element are bonded together by an optical adhesive.
An optical device according to any one of claims 1 to 31. 33. A crystal plate as a birefringent medium is provided with a transparent electrode and an alignment film, which is integrated with a liquid crystal element.
The optical device according to any one of 1. 34. The optical device according to claim 1, which is configured as a direct-view type, reflective type, or projection type display device. 35. The optical device according to claim 1, which is used in a wavelength range of visible light. 36. The optical device according to claim 1, wherein the wobbling element is combined with a solid-state image pickup element to be configured as a visible light or infrared light image pickup apparatus. 37. The optical device according to claim 36, wherein a wobbling element, an optical low-pass filter, and a solid-state image sensor are combined. 38. The optical device according to claim 37, wherein a quarter-wave plate is arranged in the optical path between the wobbling element and the optical low-pass filter.