JPH05323307A - Direct view type display and projection type display - Google Patents

Abstract

PURPOSE:To improve the light utilization rate of a display using an electrooptical modulating element and to provided the direct view type display which is small in power consumption and compact and a projection type display which is simple in structure and low in power consumption. CONSTITUTION:Spectral color filters 12 of a direct view type display using the electrooptical modulating element consist of an optical element 11 which has plural coloring matters at every picture element, and spectrally diffracts passing light at every picture element in coloring matter units. The optical element 11 is composed of a dichroic film or prism. The optical element 11 can be equipped with a lens array 20 which is positioned and arranged at every picture element. Further, the electrooptical modulating element can be placed in transmission-scattering type mode. The optical element 11 is equipped with a light guide 18 which is linearly arranged and expands light in two dimensions. Further, the light can be projected on a screen from a projection lens through the optical element 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct view type display and a floodlight type display. The direct-view display of the present invention is, for example, a liquid crystal or a transparent ceramic (PLZT) which is an electro-optical modulator.
Composed of. In the present specification, the "electro-optical modulation element" means an element that modulates by transmitting-absorbing or transmitting-scattering light by applying a voltage.

[0002]

2. Description of the Related Art FIG. 11 is a diagram for explaining a conventional color liquid crystal display. In FIG.
The color liquid crystal display includes a lower glass substrate 111 having a transparent electrode 117 formed for each pixel, and three primary color filters of red (R), green (G), and blue (B) formed for each pixel. 114 and the color filter 114
Liquid crystal layer existing in a space formed by the upper glass substrate 112 having the protective film 116 of FIG. 118, a polarizing plate 119 provided on the opposite side of the upper glass substrate 112 from the liquid crystal layer 118, and the liquid crystal layer 11 of the lower glass substrate 111.
8, a polarizing plate 1110 provided on the opposite side to the polarizing plate 119 and oriented in a direction orthogonal to the polarizing plate 119, a fluorescent tube 1112, and a fluorescent tube 1.
And a backlight including a diffusion plate 1111 for diffusing the light of 112.

The operation of the color liquid crystal display having the above structure will be described. In a state where no voltage is applied to the transparent electrodes 115 and 117, the light emitted from the fluorescent tube 1112 is diffused by the diffusion plate 1111 and then the polarization direction of the light is aligned by the polarizing plate 1110. The liquid crystal layer 118 rotates the plane of polarization of the light whose vibration directions are uniform, and then passes through the polarizing plate 119. On the other hand, the transparent electrode 11
When a voltage is applied to 5 and 117, the applied voltage changes the alignment direction of the liquid crystal molecules and the polarization plane does not rotate, so that light cannot pass through the polarizing plate 119. This phenomenon is well known as twisted nematic. However, it is known that the transmittance of the liquid crystal layer is controlled by applying an electric field to the liquid crystal layer by another principle.

In order to perform color display, as shown in FIG. 11, a color filter 114 of R, G and B is arranged for each pixel. The light transmission of the R, G, and B color filters 114 is independently controlled by the liquid crystal layer 118. Then, the light transmitted through the color filter 114 is an additive color mixture and an arbitrary color is transmitted through the polarizing plate 119.
That is, a color image is reproduced on the polarizing plate 119 of the color liquid crystal display.

FIG. 12 is a diagram for explaining a conventional floodlight type color display. In FIG.
The light source 1221 is reflected by the reflection plate 1222 and the like, and after passing through the lens 1223, the spectral filters 1224, 1
225 separates into three primary colors of R, G, and B. The separated light beams of the respective colors are used for the liquid crystal display devices LC1 to L.
After passing through C3, the spectral filters 1226, 1227,
1228. Then, the combined light beam is projected onto the screen SC by the light projecting lens 1229. At this time, the liquid crystal display devices LC1 to LC3
A desired color image is projected onto the screen SC by controlling the.

[0006]

In the above-mentioned color liquid crystal display, the color filter 114 needs to narrow the spectral band to produce a beautiful color. However, since the color filter 114 is an absorption type and undesired bands other than the narrow band are absorbed, there is a problem that light is attenuated and the display surface becomes dark. In order to solve this problem, the conventional color liquid crystal display has a fluorescent tube 1112 and a diffusion plate 1 as shown in FIG.
A backlight composed of 111 is provided. The backlight is brightened by increasing the power. That is, in the conventional color liquid crystal display, in order to make the color display beautiful, the power of the backlight must be increased accordingly. The liquid crystal display has a problem that its merit is diminished although it is characterized by low power consumption. In addition, the consumption of the electric power causes heat generation, which causes a new problem of heat dissipation. For example,
A color liquid crystal display used in a personal computer or the like has a required brightness (about 50 to 1) at around 10W.
It is earning 00ftl).

Further, the liquid crystal display devices LC1 to LC3 in the floodlight type display shown in FIG. 12 do not use the color filter as shown in FIG. for that reason,
There is little attenuation due to the absorption of light in the liquid crystal display devices LC1 to LC3. However, the floodlight type display requires a long light path from the light source 1221 to the floodlight lens 1229. The light in this long path is scattered and attenuated on the way. Therefore, even in the floodlight type display, in order to secure the brightness on the screen, there is a problem that the high brightness light source must be used while being cooled. Further, the floodlight type display has a drawback that the display becomes large because the optical system including a plurality of spectral filters, a liquid crystal display device, a lens and the like is complicatedly configured.

As described above, both the direct-view color liquid crystal display provided with the absorption type color filter and the floodlight type display using three liquid crystal display devices have poor light utilization rate and display brightness on the display. Low.
In addition, each of the above displays has problems in terms of heat generation, size, and weight.

The present invention has been made to solve the above problems. In a display using an electro-optical modulator, the light utilization rate is improved and a low power consumption characteristic of the electro-optical modulator is provided. It is intended to provide a compact and direct view display. Another object of the present invention is to provide a low power projection type display having a simple structure.

[0010]

[Means for Solving the Problems]

(First Invention) In order to achieve the above-mentioned object, a direct-view display using the electro-optical modulator of the present invention has a plurality of dyes for each pixel unit, and the light passing through the pixel unit is transferred for each dye. It is equipped with a spectral color filter composed of an optical element (11 in FIG. 1 to FIG. 3) for spectrally splitting.

(Second Invention) The optical element (11) in the direct-view display of the present invention is a dichroic film (see FIG. 4).
42 to 44) are formed.

(Third Invention) The optical element (11) in the direct-view display of the present invention is composed of a spectral color filter composed of prisms (51 and 61 in FIGS. 5 and 6).

(Fourth Invention) The optical element (11) in the direct-view type display of the present invention is a lens array (20 in FIGS. 1 to 4, 6, and 10) arranged in alignment with each pixel. ).

(Fifth Invention) Electro-optical modulator in the direct-view display of the present invention (26 in FIGS. 2 and 3)
Is a transmission-scattering mode (FIG. 9).

(Sixth Invention) The optical element (11) in the direct-view display of the present invention is one-dimensionally arranged, and a light guide for two-dimensionally magnifying the light dispersed by the one-dimensional optical element (11). (18 in FIGS. 1 to 3).

(Seventh Invention) The projection display of the present invention projects light from the projection lens (73 in FIG. 7) to the screen (SC in FIG. 7) via the optical element (11 in FIG. 7). Configured to glow.

[0017]

[Work]

(First Invention) An electro-optical modulation element is an element that undergoes modulation such as transmission-absorption or transmission-scattering of light when a voltage is applied, and has, for example, a liquid crystal device or a crystal structure made of an inorganic material. Transparent ceramics (PLZT)
Etc. A direct-view display using an electro-optical modulator has a plurality of pigments for each pixel unit. For example, in the case of full color, a filter for separating the three primary colors is required, and in the case of multicolor, filters for that number of colors are required. The light passing through each pixel unit is dispersed by the optical element for each color. That is, since the optical element serving as a color filter is a spectral type that takes out a difference in optical refractive index instead of an absorption type, it is a narrow band color filter having high energy intensity. Further, since the optical element has a polarization characteristic and a polarizing plate is unnecessary, the size of the display can be reduced.

(Second Invention) A dichroic film is formed on the spectral surface of the optical element to be a color filter. In the dichroic film, a film having a large refraction and a film having a small refraction are alternately formed, and light can be split into, for example, three primary colors of R, G, and B depending on how the films are provided. The dichroic film-formed optical element disperses light only due to the difference in the refractive index of the film, and therefore does not absorb light and does not attenuate the transmitted light energy.

(Third Invention) The optical element to be the color filter is composed of a prism. The light incident on the prism has a different refractive index depending on its color, so that the light can be split into three primary colors of R, G, and B, for example. Since an optical element using a prism disperses light only by the difference in its refractive index, it does not absorb light and does not attenuate the transmitted light energy.

(Fourth Invention) Since the optical element is provided with the lens array that is aligned with each pixel, there is no light scattering and the light utilization rate is high.

(Fifth Invention) The electro-optical modulator can be applied to a direct-view display of transmission-scattering type instead of transmission-absorption type as in a liquid crystal device. Examples of the transmission-scattering type electro-optical modulation element include transparent ceramics (PLZT). In the transmission-scattering type electro-optical modulation element, even if there is some attenuation, since the above-mentioned optical element serving as a color filter is used, brightness can be obtained as a display.

(Sixth Invention) The light dispersed from the one-dimensionally arranged optical elements is two-dimensionally expanded by a light guide. Therefore, since the optical element does not have a two-dimensional structure, the display can be downsized.

(Seventh Invention) In the color filter of the floodlight type display, since the above-mentioned optical elements are arranged in the optical path, for example, three R, G, and B are formed by one optical element.
Can disperse into primary colors. Therefore, the floodlight type display using the optical element becomes a small and simple device, and an image of bright brightness is projected on the screen without light attenuation.

[0024]

EXAMPLE FIG. 1A shows a plan view of an optical element which is an example of the present invention. 1 (b) is shown in FIG. 1 (a).
FIG. In FIGS. 1A and 1B, the optical element 11 is composed of, for example, a spectroscopic type micro filter 12 which will be described later and is composed of three primary colors. The optical element 11 is arranged two-dimensionally, for example, a filter row (R) 13 that transmits red, a filter row (G) 14 that transmits green, and a filter row (B) 15 that transmits blue.
The desired numbers are arranged so that and correspond to one pixel. Further, in the optical element 11, each of the spectral micro filters 12 is fixed by a frame 16.

As shown in FIG. 1B, the light passes through a fluorescent tube 17, a light guide 18, and a lens array 20 made up of two-dimensional microlenses 19 for each R,
The three primary colors G and B are each pixel-based
The light is focused on the filter 12. Note that FIG. 1A shows the optical element 11 in a plan view. The filter rows 13 to 15 for the three primary colors of R, G, and B, and the lens array 20 are formed in an elongated stripe shape or a matrix array shape. Further, the lens array 20 can be omitted depending on the nature of light incident on the filter rows 13 to 15. Further, the lens array 20 is
It can be integrally formed with the filter rows 13 to 15.

FIG. 2 is a diagram for explaining one embodiment of the direct-view color liquid crystal display according to the present invention. Figure 2
In FIG. 1, the optical element 11, the fluorescent tube 17, the light guide 18, and the lens array 20 shown in FIG. 1 are arranged below the lower glass substrate 21. A transparent electrode 22 corresponding to a pixel is formed on the other surface of the lower glass substrate 21. A transparent electrode 23 common to each pixel is formed below the upper glass substrate 24. A liquid crystal layer 26 exists between the lower glass substrate 21 and the upper glass substrate 24 and is sealed by a sealing material 25. The optical element 11 shown in FIG. 2 is formed outside the lower glass substrate 21 and is adjacent to the lens array 20. Therefore, the optical element 11 can be formed integrally with the lens array 20. Further, the lens array 20 can be omitted if the light from the light source has a strong directivity.

FIG. 3 is a view for explaining another embodiment of the direct-view type color liquid crystal display according to the present invention. In FIG. 3, the optical element 11 is separated from the lens array 20 and formed on the upper glass substrate 24. With such a configuration, since the optical element 11 is adjacent to the liquid crystal layer 26, color shift due to parallax can be prevented. On the other hand, the lens array 20 is arranged adjacent to the light guide 18 or integrally molded.

FIG. 4 is a diagram for explaining an embodiment of the optical element according to the present invention. In FIG. 4, the lens array 20 includes microlenses 41, 4 corresponding to respective pixels.
1 ', 41 ", ..., And the optical elements 11, 11', 11", ... Correspond to the respective microlenses 41, 41 ', 41 ",. Next, the configuration of the optical element 11 will be described.
In No. 1, a micro prism-shaped triangular structure is formed on the light incident side. On the inclined surface of the micro prism, for example, dichroic films 42 to 44 corresponding to the three primary colors are provided.
Is formed. Also, each optical element 11, 11 ', 11 "
Are provided with the microlenses 41, 41 ', 41 ", respectively.

The light passing through the microlens 41 of the lens array 20 is separated by the dichroic films 42 to 43 of the prism. That is, the dichroic film 42 discriminates the green (G) light and the dichroic film 43.
Discriminates the red (R) light, and the dichroic film 44
Discriminate blue (B) light. The separation layer 45 improves the separation of the three primary colors of R, G, and B so that the display on the display can be seen clearly. For example, the separation layer 45 may be a black plate provided on the light emitting surface of the optical element 11 or a partition plate inserted between the three primary color beams of R, G, and B.

As a molding example of the optical element 11, the outer shape is completed by using a plastic molding process. After that, the dichroic films 42 to 44 are formed by forming an interference film into a multilayer for each color by mask vapor deposition or sputtering. If the directivity of the light incident on the optical element 11 is strong, the lens array 20 is unnecessary. The advantage of this method is that if the dichroic films 42 to 44 positively utilize the ability to deflect, it is possible to omit the deflecting plate as shown in the conventional example.

The simplest manufacturing method of the lens array 20 is as follows.
The lens shape can be made by pressing or injecting a plastic plate. Further, when it is desired to improve the light utilization efficiency and the color separation accuracy of the filter, it is possible to improve the refractive index distribution by diffusing impurities in the glass plate in order to improve the dimensional accuracy of the lens array 20 and the lens performance. ..

FIG. 5 is a view for explaining another embodiment of the optical element according to the present invention. In FIG. 5, the optical elements 11, 11 ′ and 11 ″ are examples in which prisms 51, 51 ′ and 51 ″ are used for the beam discrimination method of the three primary colors of R, G and B. The light incident on the optical element 11 is reflected by the prism 5
By passing 1, the light is refracted depending on the wavelength due to the refractive index difference between the prism 51 and the medium 52 such as air,
Take advantage of the different arrival points. The short blue light (B)
Turn well. Red light (R) having a long wavelength is not bent so much and is discriminated as shown in FIG. In order to make the separation of light of different wavelengths clearer, a separation layer 45 is used as shown in FIG. The simplest manufacturing method of the prism 51 is formed by using a transparent plastic such as acrylic and forming an array with a mold. Of course, it can be realized with glass. 4 and 5, the three primary colors R, G, and B appear to be separated for each block, but they are actually connected.

FIG. 6 is a view for explaining still another embodiment of the optical element according to the present invention. In FIG. 6, prisms 61, 61 ′, 61 ″ are used for the optical elements 11, 11 ′, 11 ″ as in the embodiment shown in FIG. 5, and they are combined with the lens array 20. For example, the prism 61 is composed of two members 62 and 63. After the members 62 and 63 are pasted together, a necessary number of the three primary colors of R, G, and B are aligned in units of pixels, and the prism surfaces are arranged in the light incident direction. , Polish to be slanted. In this way, the orthorhombic optical element 11 is obtained. As described above, the optical element 11 shown in the embodiment shown in FIGS. 4 to 5 can be used for the direct-view type display shown in FIGS. 2 and 3.
It can also be applied to floodlit displays.

FIG. 7 is a diagram for explaining an embodiment of the floodlight type display according to the present invention. In FIG.
The light emitted from the light source 71 is reflected by the reflecting plate 72 and then projected onto the screen 74 by the light projecting lens 73 via the optical element 11 shown in FIGS. Since the optical element 11 of the present embodiment has replaced the conventional light absorption type filter with the spectral type filter, the light utilization efficiency is improved three times or more. In this embodiment, since the complicated optical system as in the conventional example shown in FIG. 12 can be avoided, the structure of the entire projection type display can be simplified, and the size, weight and cost of the display can be greatly improved. Further, in the floodlight type display of this embodiment, since the optical path length from the light source 71 is shortened, unnecessary light scattering is avoided and the brightness can be doubled or more.

FIG. 8 is a diagram showing a spectrum of light dispersed by the optical element of this embodiment. As shown in FIG. 8, R, G, and B peaks are emphasized in the spectral characteristics after being spectrally separated by the optical element of the present example, and high color rendering properties are obtained. Conventionally, such a light source has been used, but in the present embodiment, the usable selection range is widened as compared with the conventional high color rendering light source. That is, according to the present invention, in order to improve the light utilization rate, it is possible to select either the spectral characteristic that is dispersed by the optical element or the light source. On the other hand, conventionally, for example, in the color filter 114 of FIG. 11, the wavelength characteristic is broad and it is difficult to improve it. Therefore, the light source had to emphasize the color rendering property. However, the spectral characteristics of the optical element of the present embodiment can be freely designed by controlling the film thickness or the number of layers when forming a dichroic film, for example. Therefore, it is possible to select a spectrum that gives a light utilization rate and a clear color.

FIG. 9 is a diagram for explaining one embodiment of the present invention in which the electro-optical modulator adopts the transmission-scattering mode. If the transmission-scattering mode as shown in FIG. 9 is adopted as the field effect element in order to improve the light utilization efficiency and the display brightness, which is the object of the present invention, the effect is doubled. The transmission-scattering mode is, for example, a mode called a polymer dispersion type, and as shown in FIG. 9 (A), molecules in dispersed particles take a random orientation in a state where no electric field is applied. For this reason, the light incident on the electro-optical modulator is scattered on the surface of the particle and the amount of transmitted light decreases. On the other hand, the above electricity
When an electric field is applied to the optical modulation element, as shown in FIG. 9B, the molecules in the particles are oriented in the same direction, and light is transmitted without being scattered. Since this mode does not require the deflector plate as shown in FIG. 11, the light utilization rate is high.

However, in this mode, the effect is halved unless the directivity of light is increased in a scattering state where no electric field is applied. When this mode is combined with the present embodiment, first, there is an effect that the light utilization rate is doubled. At the same time, the optical element of the present embodiment can emit light having a strong directivity, and thus the display effect (for example, the contrast is increased due to the increased scattering effect) is improved. For example, the combination of this mode and this embodiment improved the brightness up to 6 times. At the same time, in this mode using the conventional filter, the contrast was limited to 30: 1, but by combining with this embodiment, it was possible to improve it to 100: 1.

FIG. 10A is a sectional view for explaining another embodiment of the present invention, and FIG. 10B is the same plan view. Figure 1
At 0, the light from the light source 17 is incident from the side of the display device through the optical element 100 via the cylindrical condenser lens or the lens array 20. Optical element 1 of this embodiment
00 is one-dimensional. With the optical element 100, R, G,
The light separated into the three primary colors B is spread in a plane by the light guides 101 corresponding to R, G, and B, and is emitted to, for example, a liquid crystal display device arranged above. In this case, the basic structure of the optical element 100 is the same as that of the example shown in FIGS. 4 to 6, but the optical element is small and the cost can be easily reduced because the planar expansion is not required.

Although this embodiment has been described in detail above, it is not limited to this embodiment. Various design changes can be made without departing from the invention described in the claims. For example, although the present embodiment has been described with the three primary colors of R, G and B, it is also possible to use a multi-color that uses a plurality of colors. In addition, it goes without saying that well-known or known techniques such as plastic or glass molding techniques can be used for manufacturing the optical elements and the lens arrays in this embodiment.

[0040]

According to the present invention, since the spectral type optical element which does not absorb light is used as the color filter, it is possible to realize a direct-view type display having a light utilization efficiency at least three times higher than that of the conventional one. Further, if the transmission-scattering mode is adopted as the electro-optical modulation element of the direct-view display, the light utilization rate can be further improved by a factor of 2 and the display effect can be improved. Further, by adopting the optical element of the present invention in the floodlight type display, a bright and compact device can be easily obtained.

[Brief description of drawings]

FIG. 1A is a plan view of an optical element that is an embodiment of the present invention. FIG. 1B shows a cross-sectional view of FIG.

FIG. 2 is a diagram for explaining one embodiment of a direct-view color liquid crystal display according to the present invention.

FIG. 3 is a diagram for explaining another embodiment of the direct-view color liquid crystal display according to the present invention.

FIG. 4 is a diagram for explaining an example of an optical element according to the present invention.

FIG. 5 is a diagram for explaining another embodiment of the optical element according to the present invention.

FIG. 6 is a diagram for explaining still another embodiment of the optical element according to the present invention.

FIG. 7 is a diagram for explaining an embodiment of a floodlighted display according to the present invention.

FIG. 8 is a diagram showing a spectrum of light dispersed by the optical element of the present embodiment.

FIG. 9 is a diagram for explaining one embodiment of the present invention in which the electro-optical modulator adopts a transmission-scattering mode.

10A is a sectional view for explaining another embodiment of the present invention, and FIG. 10B is the same plan view.

FIG. 11 is a diagram for explaining a color liquid crystal display in a conventional example.

FIG. 12 is a diagram for explaining a floodlight type color display in a conventional example.

[Explanation of symbols]

 11 ... Optical element 12 ... Spectral type micro filter 13, 14, 15 ... Filter row 16 ... Frame 17 ... Fluorescent tube 18 ... Optical guide 19 ... Micro lens 20. ..Lens array 21 ... Lower glass substrate 22, 23 ... Transparent electrode 24 ... Upper glass substrate 25 ... Sealing material 26 ... Liquid crystal layer 41, 41 ', 41 "... Microlens 42, 43, 44 ... Dichroic film 45 ... Separation layer 51, 51 ', 51 "... Prism 61, 61', 61" ... Prism 71 ... Light source 72 ... Reflector 73 ... Projecting lens 74 ... Screen 100 ... Optical element

Claims (7)

[Claims] 1. A direct-viewing type display using an electro-optical modulator, comprising a plurality of pigments for each pixel unit, and a spectral color filter comprising an optical element for dispersing light of the passing pixel unit for each pigment. A direct-view display characterized by having. 2. The direct-view display according to claim 1, wherein the optical element comprises a spectral color filter having a dichroic film formed thereon. 3. The direct-view display according to claim 1, wherein the optical element comprises a spectral color filter composed of a prism. 4. The direct-view type display according to claim 1, wherein the optical element comprises a spectral color filter provided with a lens array arranged in alignment with each pixel. .. 5. The direct-view display according to claim 1, wherein the electro-optical modulator is a transmission-scattering mode. 6. The optical element according to claim 1, further comprising a light guide which is arranged in one dimension and which magnifies light dispersed by the one-dimensional optical element in two dimensions. Direct-view display as described. 7. A projection type display characterized in that light is projected onto a screen from a projection lens via the optical element according to claim 1 or 4.