JP2007121693A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of reducing nonuniform color and nonuniform illuminance, which result from color aberration, and accordingly realizing high contrast. <P>SOLUTION: While a field lens 55r for red and a field lens 55g for green are disposed in equivalent positions, the refractive power of the field lens 55r for red is made lower than that of the field lens 55g for green. Thereby, an image on a liquid crystal panel 42a is accurately imaged onto both a liquid crystal panel 72r for red and a liquid crystal panel 72g for green with the same magnification. In this case, the field lenses 55r and 55g for red and green respectively are used to make the imaging magnifications identical. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a projector including a liquid crystal panel for adjusting luminance separately from a liquid crystal panel for image formation in order to improve the contrast of an image.

As a conventional projector, the transmittance of each color liquid crystal panel arranged on the RGB three-color optical path is modulated, and the transmittance of the high-definition liquid crystal panel provided on the optical path after combining the dispersed light is adjusted. When modulating and displaying a color image, there is one that makes the light transmittance of each component emitted from a high-precision liquid crystal panel proportional to the inverse γ correction values of R, G, and B (see Patent Document 1).

As a similar projector, there is one that includes an illuminance display liquid crystal panel arranged in the front stage and a video display liquid crystal panel for each color arranged in the rear stage (see Patent Document 2).

As another projector, there is a projector in which a light modulator for spatially dividing the illumination light and adjusting the amount of illumination light is provided between the RGB color liquid crystal panels and the light source for illuminating them. (See Patent Document 3).
JP-A-6-167690 FIG. 2 of JP-A-9-116840 Japanese Patent Laid-Open No. 2001-1000068

However, in the former two types of projectors in which the liquid crystal panels are arranged in two stages, it is necessary to accurately project the image of each color liquid crystal panel onto the high-definition liquid crystal panel without aberration, or the image of the illuminance display liquid crystal panel However, it is not easy to accurately correct chromatic aberration while suppressing various aberrations such as distortion.

In the latter type of projector provided with a light modulator for adjusting the amount of illumination light,
For example, since the screen is divided into four areas and brightness adjustment is performed in units of each area, there is a limit in improving the contrast, and it is not easy to make the boundaries between the areas inconspicuous.

Therefore, the present invention can reduce the occurrence of color unevenness and illuminance unevenness due to chromatic aberration,
An object is to provide a projector capable of realizing a high contrast.

In order to solve the above-described problems, a projector according to the present invention includes (a) a luminance modulation light valve for luminance-modulating light from an illuminating device, and (b) light that has been luminance-modulated by the luminance modulation light valve. A color separation optical system for separating the first to third color lights, and (c) first to third color modulations of the first to third color lights that are luminance-modulated by the luminance modulation light valve and separated by the color separation optical system, respectively. Three color modulation light valves, and (d) the first and second color light beams, which are modulated by the luminance modulation light valve and separated by the color separation optical system, to the first and second color modulation light valves, respectively. A projector including a shared relay lens system for forming an image, wherein (e) the length of an optical path from the luminance modulation light valve to the first color modulation light valve, and the second color modulation from the luminance modulation light valve The length of the optical path to the light valve is equal, and (f) the first and second color lights by the shared relay lens system are included in at least one of the optical paths of the first and second color lights separated by the color separation optical system. Is provided with chromatic aberration correction means for matching the image forming magnification.

In the projector described above, the luminance modulation light valve and the color modulation light valves are installed in two stages via a common relay lens system or the like, so that two-stage modulation is possible, and a high-contrast image can be projected. it can. In the projector, the first and second
Since the chromatic aberration correction means arranged in at least one of the optical paths of the chromatic lights matches the imaging magnifications of the first and second chromatic lights by the shared relay lens system, the chromatic aberration remaining in the shared relay lens system is compensated. An image becomes possible. That is, since the luminance modulation images of the same size can be made incident on the first and second color modulation light valves, each pixel of the first and second color modulation light valves and the luminance projected onto them. The image of each pixel of the modulation light valve can be made to substantially coincide. Therefore, each pixel can be projected without loss by reducing the light loss caused by the positional deviation between the pixels constituting the corresponding front and rear light valves.
Irradiance unevenness and color unevenness can be prevented from occurring in the projected image.

In a specific aspect of the present invention, in the projector, the sub-relay lens that forms an image on the third color modulation light valve with the third color light that has been luminance-modulated by the luminance modulation light valve and separated by the color separation optical system. A system is further provided. In this case, the sub-relay lens system enables the same image formation as the first and second color modulation light valves to the third color modulation light valve.

In another aspect of the present invention, in the projector, the shared relay lens system once forms an image of the third color light that has been luminance-modulated by the light-modulating light valve and separated by the color separation optical system, and once forms the image. And a transfer optical system for re-imaging the third color light on the third color modulation light valve. In this case, the common relay lens system and the transfer optical system enable the same image formation as the first and second color modulation light valves to the third color modulation light valve.

In yet another aspect of the present invention, the chromatic aberration correcting means forms an image of a black matrix provided on the luminance modulation light valve on a black matrix provided on at least one of the first and second color modulation light valves. The imaging magnification is corrected as described above. In this case, the black matrices of the first and second color modulation light valves and the black matrix image of the luminance modulation light valve projected onto them can be made substantially coincident. Therefore, it is possible to reduce the light amount loss caused by the positional deviation of the corresponding front and rear light valves, that is, the black matrix, and to project each pixel without loss.

In yet another aspect of the present invention, the chromatic aberration correcting means includes first and second optical elements respectively disposed on the optical paths of the first and second color lights separated by the color separation optical system. The first and second optical elements have different light collecting characteristics. In this case, it is possible to make the image of the luminance-modulated light of the same size enter the first and second color modulation light valves by using the difference between the condensing characteristics of the first and second optical elements.

In still another aspect of the present invention, the first to third condenser lenses disposed to face the first to third color modulation light valves are provided, and the first to third condenser lenses are provided. Among these, the first and second condenser lenses correspond to the first and second optical elements, and the curvature radii of the corresponding lens surfaces of the first and second condenser lenses are different from each other. In this case, the chromatic aberration can be corrected using the difference in the radius of curvature between the two condenser lenses.

In yet another aspect of the present invention, the chromatic aberration correcting means includes first and second optical elements respectively disposed on the optical paths of the first and second color lights separated by the color separation optical system. To first to third condenser lenses arranged to face the third color modulation light valve,
Among the first to third condenser lenses, the first and second condenser lenses correspond to the first and second optical elements, and the first and second condenser lenses are the first and second condenser lenses. The distances to the two color modulation light valves are different from each other. In this case, chromatic aberration can be corrected using the difference between the positions of the two condenser lenses.

In still another aspect of the present invention, the first to third condenser lenses disposed to face the first to third color modulation light valves are provided, and the first to third condenser lenses are provided. Among these, the first and second condenser lenses correspond to the first and second optical elements and have different refractive indexes. In this case, chromatic aberration can be corrected using the difference in refractive index between the two condenser lenses.

In yet another aspect of the present invention, a light combining optical system that combines image light that has been color-modulated by the first to third color modulation light valves and a combined light that is combined by the light combining optical system are projected as image light. And a projection optical system. In this case, the image light that has been color-modulated via the first to third color modulation light valves illuminated without chromatic aberration by the luminance-modulated image light is projected onto the screen by the projection optical system while being synthesized by the light combining optical system. can do.

[First Embodiment]
FIG. 1 is a schematic diagram showing an optical system of a projector 10 according to the first embodiment of the present invention.
The projector 10 is an optical device for modulating a light beam emitted from a light source in accordance with image information to form an optical image and enlarging and projecting the optical image on a screen. The optical system 30 includes a first light modulation unit 40, a color separation / projection device 50, a second light modulation unit 70, a cross dichroic prism 80, and a projection optical system 90.

The light source lamp unit 20 is a light source for collecting and emitting light beams emitted from the light source lamp 21 to the surroundings and illuminating the first light modulation unit 40 via the uniform illumination optical system 30, and a light source that is a light emitting tube. The lamp 21 and the elliptical concave mirror 2 that reflects the light source light emitted from the light source lamp 21
2 and a concave lens 23 for collimating the light source light reflected by the concave mirror 22. In the light source lamp unit 20, the light source light emitted from the light source lamp 21 passes through the concave mirror 22 and the concave lens 23 and is emitted to the uniform illumination optical system 30 side as a parallel light flux. Note that various concave mirrors such as a paraboloid can be used instead of the elliptical concave mirror 22 described above, and when the parabolic mirror is used, the above-described concave lens 23 is not necessary.

The uniform illumination optical system 30 divides the light beam emitted from the light source lamp unit 20 into a plurality of partial light beams, and makes the plurality of light beams overlap and enter the target illumination region, and the in-plane illuminance of the illumination region is increased. It is an optical system for making uniform, and functions as an illumination device for generating uniform illumination light in cooperation with the light source lamp unit 20. The uniform illumination optical system 30 includes a first lens array 31, a second lens array 32, a polarization conversion member 34, and a condenser lens 35.

The first lens array 31 has a function as a light beam splitting optical element that splits the light beam from the light source lamp unit 20 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the system optical axis OA. It is configured with a small lens. The contour shape of each small lens is set so as to be almost similar to the shape of the image forming area (effective area) of the liquid crystal panel 42a constituting the first light modulator 40 described later. The second lens array 32 is an optical element that collects a plurality of partial light beams divided by the first lens array 31 described above, and in the same manner as the first lens array 31, a matrix is formed in a plane orthogonal to the system optical axis OA. However, it is not necessary that the contour shape of each small lens corresponds to the shape of the image forming area of the liquid crystal panel 42a.

The polarization conversion member 34 is formed of a PBS array and a phase difference plate, and has a role of aligning the polarization direction of each partial light beam divided by the first lens array 31 with one direction of linearly polarized light.
Although the detailed illustration of the PBS array of the polarization conversion member 34 is omitted, the system optical axis O
A configuration in which polarization separation films and reflection mirrors that are inclined with respect to A are alternately arranged.
The former polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The reflected other polarized light beam is bent by the latter reflecting mirror, and is emitted in the emission direction of the one polarized light beam, that is, the direction along the system optical axis OA. The polarization direction of any of the emitted polarized light beams is converted by a phase difference plate provided in a stripe shape on the light beam exit surface of the polarization conversion member 34, and the polarization directions of all the polarized light beams are made uniform. By using such a polarization conversion member 34, the light source lamp 2
Since the light beam emitted from 1 can be aligned with a polarized light beam in one direction, the first light modulation unit 4
The utilization factor of the light source light used at 0 can be improved.

The condenser lens 35 condenses a plurality of partial light beams that have passed through the first lens array 31, the second lens array 32, and the polarization conversion member 34, and is provided in the first light modulation unit 40.
This is a superimposing optical element for making the light incident on the image forming area (effective area). In other words, the partial light beams divided by the first lens array 31 can be incident on the liquid crystal panel 42a without being shifted by the condenser lens 35, and the liquid crystal panel 42a can be illuminated uniformly.

The first light modulation unit 40 converts the illumination light uniformized through the uniform illumination optical system 30 to the system optical axis O.
This is for spatially modulating the luminance in a plane perpendicular to A. The first light modulation unit 40 includes an incident lens 41, a liquid crystal panel (liquid crystal display panel) 42a, polarization filters 43b and 43b, and an emission lens 44, and functions as a first light modulation device. Here, the liquid crystal panel 42a and the pair of polarizing filters 43b and 43b sandwiching the liquid crystal panel 42a constitute a luminance modulation light valve for two-dimensionally modulating the illumination light based on image information.

In the first light modulator 40, the illumination light incident from the uniform illumination optical system 30 side illuminates the image forming region in the liquid crystal panel 42 a for luminance modulation via the incident lens 41. The liquid crystal panel 42a is obtained by hermetically sealing a liquid crystal, which is an electro-optical material, between a pair of transparent glass substrates. For example, a given image signal (for example, a luminance signal or a correction to the luminance signal is corrected using a polysilicon TFT as a switching element). The polarization direction of the incident polarized light beam is modulated in accordance with the signal). That is, the liquid crystal panel 42a is a non-light-emitting and transmissive light modulation device for changing the spatial distribution of the polarization direction of the incident illumination light. The illumination light incident on the liquid crystal panel 42a is applied to the liquid crystal panel 42a. The polarization state is adjusted for each pixel in accordance with the drive signal or control signal input as an electrical signal. At that time, the polarization filters 43b and 43b adjust the polarization direction of the illumination light incident on the liquid crystal panel 42a, and extract modulated light having a predetermined polarization direction from the light emitted from the liquid crystal panel 42a. That is, the first light modulation unit 40 attenuates uniform illumination light in units of pixels, and luminance modulation is achieved with a two-dimensional distribution corresponding to image information.

The incident lens 41 is for adjusting the angle at which the partial light beam from the uniform illumination optical system 30 is incident on the liquid crystal panel 42a, and the exit lens 44 is for adjusting the exit angle of the modulated light from the liquid crystal panel 42a and the like. It is for adjustment.

The color separation / projection device 50 is for separating the image light whose luminance has been modulated through the first light modulation unit 40 into each color light and projecting it onto the second light modulation unit 70, and the first and second dichroic mirrors. 5
1a, 51b, reflecting mirrors 53a, 53b, 53c, 53d, double-sided mirror 54, field lenses (optical elements) 55r, 55b, 55g, and relay lenses 61, 62.

Among these, the color separation optical system including the first and second dichroic mirrors 51a and 51b converts the image light whose luminance is modulated by the first light modulation unit 40 into blue (B) color light, green (
G) Separated into three image lights of color light and red (R) color light. Each dichroic mirror 51a,
Reference numeral 51b denotes an optical element obtained by forming a dielectric multilayer film having a wavelength selection function of reflecting a light beam in a predetermined wavelength region and transmitting a light beam in another wavelength region on a transparent substrate, and the system optical axis They are arranged in a state of being inclined with respect to OA. First dichroic mirror 51a
Reflects and branches the blue light LB, which is a blue component, from the monochrome image light, and transmits the remaining green light LG and red light LR. The second dichroic mirror 51b reflects the green light LG that is the green component of the image light that has passed through the first dichroic mirror 51a and passed through the reflection mirror 53a and the relay lens 61, and the red light LR that is the red component. Make it transparent.

In this color separation / projection apparatus 50, the luminance-modulated image light incident from the uniform illumination optical system 30 via the first light modulation section 40 first enters the first dichroic mirror 51a. Of the image light, the red light LR is to be guided to the first optical path OP1, passes through the first dichroic mirror 51a, passes through the reflection mirror 53a and the relay lens 61, passes through the second dichroic mirror 51b, and is reflected by the reflection mirror. The light then enters the final stage condensing lens, that is, the field lens 55r via 53b. Further, the green light LG of the image light is to be guided to the second optical path OP2, passes through the first dichroic mirror 51a, is reflected by the second dichroic mirror 51b through the reflection mirror 53a and the relay lens 61, The light passes through the double-sided mirror 54 and enters the final stage condensing lens, that is, the field lens 55g. Furthermore, the blue light L of the image light
B is to be guided to the third optical path OP3, is reflected by the first dichroic mirror 51a, passes through the double-sided mirror 54, the relay lens 62, and the reflecting mirrors 53c and 53d, and is the final stage condensing lens, that is, the field lens 55b. Is incident on. In the above description, the relay lens 62, the field lens 55b, and the like constitute a secondary relay lens system.

Here, the first optical path OP1 for red, the second optical path OP2 for green, and the third optical path O for blue.
P3 is an equivalent system in which the effective lengths of the optical paths are equal to each other. More specifically, the red component of the image light whose luminance is modulated by the first light modulation unit 40 is used for image information modulation provided in the second light modulation unit 70 described later by the relay lens 61 in the first optical path OP1. LCD panel 7
The image is projected to the image forming area in 2r at the same magnification. Similarly, the green component of the image light whose luminance is modulated by the first light modulation unit 40 is a liquid crystal panel 72g for image information modulation provided in the second light modulation unit 70 by the relay lens 61 in the second optical path OP2. The image is projected to the image forming area at the same magnification. In addition, the blue component of the image light whose luminance is modulated by the first light modulation unit 40 is the third optical path OP3.
The image is projected at the same magnification on the image forming area in the liquid crystal panel 72b for image information modulation provided in the second light modulator 70 by the relay lens 62.

The relay lenses 61 and 62 shown in the figure are composed of a single lens for convenience of explanation, but are actually a projection optical system composed of a large number of lenses, and distortion and other distortions and various aberrations are greatly reduced. It is a highly accurate optical system. The relay lenses 61 and 62 are telecentric on both sides as a relay lens system including the emission lens 44 and the field lenses 55r, 55b, and 55g. As a result, the liquid crystal panel 42a and the liquid crystal panels 72r, 72g, and 72b are allowed to be displaced in the system optical axis OA direction, and the image of the liquid crystal panel 42a is placed on the liquid crystal panels 72r, 72g, and 72b. Each can be accurately projected at the same magnification.

The second light modulator 70 includes three liquid crystal panels 72r, 72g, and 72b on which the three color image lights LB, LG, and LR are incident, and three sets arranged so as to sandwich the liquid crystal panels 72r, 72g, and 72b. Polarization filters 73r, 73g, and 73b, and functions as a second light modulation device. Here, a liquid crystal panel 72r for red light LR and a pair of polarizing filters 73r sandwiching the liquid crystal panel 72r.
, 73r constitute a color modulation light valve for two-dimensionally modulating the intensity of the red light LR of the image light after luminance modulation based on image information. Similarly, the liquid crystal panel 7 for green light LG
2g and the corresponding polarizing filters 73g and 73g also constitute a green color modulation light valve,
The liquid crystal panel 72b for the blue light LB and the polarizing filters 73b and 73b also constitute a blue color modulation light valve.

Each of the liquid crystal panels 72r, 72g, 72b is a liquid crystal which is an electro-optical material sealed between a pair of transparent glass substrates. For example, each of the liquid crystal panels 72r, 72g, 72b is a polysilicon TFT as a switching element, The polarization direction of the polarized light beam incident on the light is modulated. That is, each of the liquid crystal panels 72r, 72g, and 72b is a non-light-emitting and transmissive light modulation device for changing the spatial distribution of the polarization direction of the incident light beam, and each of the liquid crystal panels 72r, 72g.
, 72b, the respective color lights LB, LG, LR respectively enter the liquid crystal panels 72r, 72g,
The polarization state is adjusted in units of pixels in accordance with the drive signal or control signal input as an electrical signal to 72b. At that time, the polarization direction of the luminance-modulated image light incident on the liquid crystal panels 72r, 72g, and 72b is adjusted by the polarization filters 73r, 73g, and 73b, and the light is emitted from the liquid crystal panels 72r, 72g, and 72b. Modulated light having a predetermined polarization direction is extracted from the light.

Note that the contours of the image forming regions (effective regions) of the liquid crystal panels 72r, 72g, 72b are congruent with the contours of the image forming regions (effective regions) of the liquid crystal panel 42a provided in the first light modulator 40. The image light formed by the luminance modulation liquid crystal panel 42a is projected at the same magnification onto the image information modulation liquid crystal panels 72r, 72g, 72b with the same image size.

As is apparent from the above description, the second light modulation unit 70 performs light modulation again on the monochrome image light whose luminance is modulated by the first light modulation unit 40 based on the display image data. That is, the image light of each color that has passed through the second light modulator 70 has extremely high contrast due to two-stage modulation.

The cross dichroic prism 80 is a light combining optical system that forms a color image by combining optical images modulated for each color light emitted from the polarizing filters 73r, 73g, and 73b. This cross dichroic prism 80 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a pair of dielectric multilayer films 81 and 82 intersecting in an X shape are formed at the interface where the right angle prisms are bonded together. Is formed. One first dielectric multilayer film 81 reflects blue light, and the other second dielectric multilayer film 82 reflects red light. The cross dichroic prism 80 reflects the red light LR from the liquid crystal panel 72r by the second dielectric multilayer film 82, and emits the green light LG from the liquid crystal panel 72g to the first and second dielectrics. Multilayer film 81
, 82, and the blue light LB from the liquid crystal panel 72b is reflected by the first dielectric multilayer film 81 and emitted to the right in the traveling direction.

The image light combined by the cross dichroic prism 80 in this manner is projected as a color image on a screen (not shown) at an appropriate magnification through a projection optical system 90 as a magnification projection lens.

FIG. 2 shows two field lenses 55r and 55g provided on the emission side of the color separation projector 50.
It is an enlarged view explaining the shape of this. In the first optical path OP1 for red, the field lens 55r is disposed so as to face and follow the light incident side surface ISr of the liquid crystal panel 72r, that is, one polarizing filter 73r. The liquid crystal panel 72r is disposed so as to face the side surface 80a of the cross dichroic prism 80 and to follow the side surface 80a. In the second optical path OP2 for green, the field lens 55g is disposed so as to face and follow the light incident side surface ISg of the liquid crystal panel 72g, that is, one polarization filter 73g.
The liquid crystal panel 72g is disposed so as to face the side surface 80b of the cross dichroic prism 80 and to follow it.

The incident surface SR1 of the red field lens 55r and the green field lens 55g
Is a convex lens surface, and the exit surface SR of the former field lens 55r.
2 and the exit surface SG2 of the latter field lens 55g are both flat lens surfaces.
Here, the radius of curvature of the incident surface SR1 of the red field lens 55r is, for example, larger than the radius of curvature of the incident surface SG1 of the green field lens 55g. The radius of curvature of the exit surface SR2 of the red field lens 55r is equal to the green field lens 5.
For example, it is equal to the radius of curvature of the 5 g exit surface SG2. That is, the red field lens 55r has different optical characteristics from the field lens 55g, and the red field lens 55r has a smaller refractive power than the green field lens 55g. On the other hand, if the relay lens 61 is slightly excessively color corrected, if the field lens 55r is exactly the same as the field lens 55g, the liquid crystal panel 4
The image 2a is projected at a relatively small magnification on the red liquid crystal panel 72r and is projected at a relatively large magnification on the green liquid crystal panel 72g. In other words, the field lens 55r
Is exactly the same as the field lens 55g, the imaging magnification of the red light LR passing through the relay lens 61 and the field lens 55r is larger than the imaging magnification of the green light LG passing through the relay lens 61 and the field lens 55g. When the alignment with respect to the relay lens 61 is performed with the green light LG as a reference, when the image of the liquid crystal panel 42a is projected onto both the liquid crystal panels 72r and 72g without blur, the image of the liquid crystal panel 42a becomes the liquid crystal panel 72.
There is a possibility that the imaging magnification is lowered by being formed before r. Therefore, the red field lens 55r and the green field lens 55g are disposed at equivalent positions, but the refractive power of the red field lens 55r is smaller than the refractive power of the green field lens 55g. By doing so, the image of the liquid crystal panel 42a is formed on both the red liquid crystal panel 72r and the green liquid crystal panel 72g accurately at the same magnification. This means that each pixel constituting the liquid crystal panel 42a is accurately transferred to each pixel constituting the liquid crystal panels 72r and 72g for both colors, and a black matrix for partitioning each pixel constituting the liquid crystal panel 42a. Means that it is accurately projected onto the black matrix partitioning each pixel constituting the liquid crystal panels 72r and 72g for both colors. Here, the red field lens 55r and the green field lens 55g function as chromatic aberration correction means for matching the imaging magnification.
Note that the black matrix is a light shielding portion that blocks light to a wiring portion or a transistor portion provided around each pixel of the liquid crystal panel.

FIG. 3 is a diagram illustrating a configuration example of the relay lens 61. The common relay lens system LLS including the relay lens 61 and the like has an imaging magnification β at the e-line wavelength (green) when the red field lens 55r is the same as the green field lens 55g. = 1
. Although it is 0000, the imaging magnification β is 0.9965 at the c-line wavelength (red).

For this reason, in this embodiment, adjustment is performed to slightly increase the radius of curvature of the red field lens 55r with reference to the green field lens 55g. Specifically,
The data of the green field lens 55g includes an incident-side radius of curvature r1 = 50.0 mm, an exit-side radius of curvature r2 = ∞, a lens thickness t = 6.0 mm, and a glass material BK7 (nd = 1.516).
8). On the other hand, the data of the red field lens 55r is the incident side curvature radius r1 =
51.68 mm, exit side radius of curvature r2 = ∞, lens thickness t = 6.0 mm, glass material BK
7. As a result, in this shared relay lens system LLS, the projection magnifications of the e-line (green) and the c-line (red), that is, the imaging magnification are both 1.0000.

In the above description, if the field lens 55r is exactly the same as the field lens 55g, the imaging magnification of the red light LR that has passed through the relay lens 61 and the field lens 55r is the same as that of the relay lens 61 and the field lens 55g. Although it is assumed that the image forming magnification of the green light LG that has passed is smaller than the imaging magnification, the reverse case may also occur. In this case, the radius of curvature of the red field lens 55r may be reduced to make its refractive power larger than that of the green field lens 55g.

FIG. 4A corresponds to a modification of FIG. 2 and is an enlarged view for explaining the arrangement and shape of a field lens 155r instead of the field lens 55r of FIG. In this case, the red field lens 155r is made of the same material as the green field lens 55g and has the same optical surface shape. However, the red field lens 155r is arranged at a position shifted from the position corresponding to the green field lens 55g.

The distance between the light emission side end surface of the red field lens 155r and the black matrix of the liquid crystal panel 72r is given by L1, and the distance between the light emission side end surface of the red field lens 155r and the side surface 80a is , L3. The distance between the light emission side end face of the green field lens 55g and the black matrix of the liquid crystal panel 72g is L
The distance between the light emitting side end face of the green field lens 55g and the side face 80b is given by L4. The red field lens 155r is provided on the liquid crystal panel 7.
The green field lens 55g is arranged relatively far from the liquid crystal panel 72g, and as a result, the relationship of L1 <L2 is established. Here, since the distance between the liquid crystal panel 72r and the side surface 80a of the cross dichroic prism 80 and the distance between the liquid crystal panel 72g and the side surface 80b of the cross dichroic prism 80 are equal, the relationship of L3 <L4 is similarly obtained. It holds. The distance L1 between the red field lens 155r and the liquid crystal panel 72r, and the green field lens 55g.
And the distance L2 between the liquid crystal panel 72g and the liquid crystal panel 72g is X = L2-L1, the image of the liquid crystal panel 42a is formed on the red liquid crystal panel 72r and the green liquid crystal panel 72g with exactly the same magnification. Is set to Here, the red field lens 155r and the green field lens 55g function as chromatic aberration correction means for matching the imaging magnification.

In a specific example, the data of the red field lens 155r is incident side radius of curvature r1 = 50.0 mm, exit side radius of curvature r2 = ∞, lens thickness t = 6.0 mm, glass material BK7, The data of the green field lens 55g is the incident side radius of curvature r1 = 50.
. 0 mm, exit radius of curvature r2 = ∞, lens thickness t = 6.0 mm, and glass material BK7. That is, both field lenses 155r and 55g are the same part. And the difference X is 0
. The field lens 155r for red and the field lens 5 for green are set to 385 mm.
The distance from the relay lens 61 is relatively large compared to 5 g. As a result, the relay lens 61 of FIG.
In the common relay lens system including the field lens 155r and the field lens 55g in FIG. 4A, the projection magnification, that is, the imaging magnification of the e-line (green) and the c-line (red) are both 1.
. 0000.

In the above description of FIG. 4A, the focal length of the red light LR of the relay lens 61 is relatively shorter than the focal length of the green light LG, but the reverse case may also occur.
In this case, the position of the red field lens 55r may be closer to the relay lens 61, that is, the liquid crystal panel 42a side than the position of the green field lens 55g.

FIG. 4B corresponds to a modification of FIG. 2 and is an enlarged view for explaining the arrangement and shape of a field lens 255r instead of the field lens 55r of FIG. In this case, the red field lens 255r has an optical surface having the same shape as the green field lens 55g, and is disposed at the same position. However, the red field lens 255r has a refractive index different from that of the green field lens 55g. In the specific example, the refractive index of the red field lens 255r is slightly smaller than the refractive index of the green field lens 55g. That is, the red field lens 255r is replaced with the green field lens 55g.
Less refractive power. As a result, the image of the liquid crystal panel 42a is formed on the red liquid crystal panel 72r and the green liquid crystal panel 72g accurately at the same magnification. Here, the red field lens 255r and the green field lens 55g function as chromatic aberration correction means for matching the imaging magnification.

In a specific example, the data of the red field lens 255r includes the incident-side radius of curvature r1 = 50.0 mm, the emission-side radius of curvature r2 = ∞, the lens thickness t = 6.0 mm, and the refractive index nd of the glass material. = 1.5000 (the Abbe number remains 64.2), and the data of the green field lens 55g are the incident-side curvature radius r1 = 50.0 mm, and the emission-side curvature radius r2 = ∞.
The lens thickness t is 6.0 mm, and the refractive index nd of the glass material is nd = 1.5168. As a result, in the common relay lens system including the relay lens 61 in FIG. 1, the field lens 255r in FIG. 4B, the field lens 55g, and the like, the projection magnifications of the e-line (green) and the c-line (red), that is, image formation. Both magnifications are 1.0000.

In the above description of FIG. 4B, the field lens 55r is assumed to be the field lens 5 temporarily.
If it is exactly the same as 5g, the relay lens 61 and the field lens 55r
The imaging magnification of the red light LR that has passed through is assumed to be smaller than the imaging magnification of the green light LG that has passed through the relay lens 61 and the field lens 55g, but the opposite may also occur. In this case, the refractive index of the red field lens 55r may be larger than the refractive index of the green field lens 55g.

In the above description based on FIGS. 1 to 4, the liquid crystal panel 42 is formed by the common relay lens 61.
Although the image a is projected onto the red and green liquid crystal panels 72r and 72g, the image of the liquid crystal panel 42a can be projected onto the green and blue liquid crystal panels 72g and 72b by the common relay lens 61. In this case, the projection magnifications for both colors can be matched by adjusting the differences in the radius of curvature, position, refractive index, etc. of the pair of field lenses 55g, 55b arranged in front of the liquid crystal panels 72g, 72b.

In a specific example, a lens similar to the relay lens 61 of FIG. 3 was used. The data of the green field lens 55g is incident side radius of curvature r1 = 50.0 mm, exit side radius of curvature r2 = ∞, lens thickness t = 6.0 mm, and glass material BK7 (nd = 1.5168). is there. On the other hand, the data of the field lens 55b for blue is incident side radius of curvature r1 = 49.6.
0 mm, exit radius of curvature r2 = ∞, lens thickness t = 6.0 mm, glass material BK7 (nd
= 1.5168). As a result, the blue projection magnification, that is, the imaging magnification is 1.0008.
From 367 to 1.000 can be matched with green.
Also, the data of the blue field lens 55b is matched with the green field lens 55g, and the blue field lens 155b is relatively closer to the relay lens 61 than the green field lens 55g. The blue projection magnification, that is, the imaging magnification can be set to 1.0008367 to 1.000 to match the green color.
Further, the refractive index of the blue field lens 55b is changed to the green field lens 55g.
By setting nd = 1.5210, which is larger than the refractive index (nd = 1.5168), the blue projection magnification, that is, the imaging magnification can be set to 1.0008367 to 1.000 to match the green color.

Furthermore, the image of the liquid crystal panel 42a can be projected onto the red and blue liquid crystal panels 72r and 72b by the common relay lens 61. In this case, the liquid crystal panels 72r and 72b
By adjusting the differences in the radius of curvature, position, refractive index, etc. of the pair of field lenses 55r and 55b arranged in the preceding stage, the projection magnifications for both colors can be matched.

[Second Embodiment]
Hereinafter, the projector according to the second embodiment will be described. Note that the projector according to the second embodiment is obtained by partially changing the projector according to the first embodiment, and the same portions are denoted by the same reference numerals and redundant description is omitted. In addition, parts that are not particularly described are the same as those in the first embodiment.

FIG. 5 is a plan view illustrating the projector 310 according to the second embodiment. This projector 310 is obtained by changing the color separation projection device 50 of the projector 10 shown in FIG. The color separation projection device 350 incorporated in the projector 310 of the present embodiment includes the second and third dichroic mirrors 51b and 351a, and the reflection mirrors 53a, 53b, 353e, and 35.
3f, field lenses 55r, 55g, and 55b, a relay lens 61, and transfer lens systems 356a to 356c. Of these, the second and third dichroic mirrors 51b
, 351a, the intensity-modulated image light is converted into blue light, green light,
And three luminous fluxes of red light. The second dichroic mirror 51b transmits the image light component of the red light LR among red, blue, and green, and reflects the image light components of the green light LG and the blue light LB. The third dichroic mirror 351a reflects the image light component of the green light LG out of the incident green light LG and blue light LB and transmits the blue light LB.

In this color separation / projection apparatus 350, the luminance-modulated image light incident from the uniform illumination optical system 30 via the first light modulation unit 40 enters the second dichroic mirror 51b via the reflection mirror 53a and the relay lens 61. The red component of the image light is the second dichroic mirror 51.
b passes through the reflecting mirror 53b and enters the final stage field lens 55r (first).
Optical path OP1). At this time, the red image light formed by the liquid crystal panel 42a is projected at the same magnification on each liquid crystal panel 72r for image information modulation so that the image sizes match. The green component of the image light is the second dichroic mirror 51b and the third dichroic mirror 351.
The light is reflected by a and enters the final stage field lens 55g (second optical path OP2). At this time, the green image light formed by the liquid crystal panel 42a is projected on each liquid crystal panel 72r for image information modulation at the same magnification as red. Further, the blue component of the image light is reflected by the second dichroic mirror 51b, passes through the third dichroic mirror 351a, and is reflected by the reflection mirror 3.
53e, 353f and transfer lens systems 356a to 356c, and then the final stage field lens 5
Incident to 5b. The transfer lens systems 356a to 356c are temporarily formed behind the third dichroic mirror 351a by the relay lens 61 as a transfer optical system.
The blue image light a is re-imaged on the liquid crystal panel 72r as an equal-size and erect image.

As a result, also in the projector 310 of the second embodiment, the image light of each color whose luminance is modulated by the first light modulation unit 40 is provided in the second light modulation unit 70 by the relay lens 61 and the transfer lens systems 356a to 356c. Further, the image is similarly projected on the liquid crystal panels 72r, 72g, 72b of the respective colors at the same magnification. At this time, as in the case of the first embodiment, the image of the liquid crystal panel 42a is projected onto the liquid crystal panels 72r and 72g for red and green by the common relay lens 61, but in front of the liquid crystal panels 72r and 72g. The radius of curvature of the pair of field lenses 55r and 55g to be disposed;
By adjusting the difference in position, refractive index, and the like, the projection magnifications for both colors can be made to exactly match.

In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can implement in a various aspect, For example, the following deformation | transformation is also possible.

That is, in the above embodiment, the two lens arrays 31 and 32 are used to divide the light from the light source lamp unit 20 into a plurality of partial light beams, but the present invention does not use such a lens array. It is also applicable to. Also, the lens arrays 31, 32
Can be replaced with a rod integrator. Furthermore, although the polarization conversion member 34 that converts the light from the light source lamp unit 20 into polarized light in a specific direction is used, the present invention is also applicable to a projector that does not use such a polarization conversion member 34.

In the second embodiment, the blue liquid crystal light valve 72b is connected to the relatively long third optical path O.
Although the transfer lens systems 356a to 356c are arranged in the third optical path OP3 while being arranged in P3, other red and green colors can be guided to the relatively long third optical path OP3.

Further, as the projector, there are a front projector that projects an image from the direction of observing the projection surface and a rear projector that projects an image from the side opposite to the direction of observing the projection surface. The projector 10 shown in FIG. , 310 can be applied to both.

It is a figure explaining the optical system of the projector which concerns on 1st Embodiment. It is an enlarged view explaining the shape of the field lens provided in the emission side of the color separation projector. It is a figure explaining the example of 1 composition of a relay lens. (A) shows the 1st modification regarding arrangement | positioning of a pair of field lens, (b) shows the 2nd modification regarding the refractive index of a pair of field lens. It is a figure explaining the optical system of the projector which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Projector, 20 ... Light source lamp unit, 30 ... Uniform illumination optical system, 31
, 32 ... Lens array, 34 ... Polarization conversion member, 35 ... Condenser lens, 40 ... First light modulation unit, 42a ... Liquid crystal panel, 43b, 43b ... Polarization filter, 50 ... Color separation and projection device, 51a, 51b ... Dichroic mirror 54 ... Double-sided mirror, 55r,
55b, 55g ... Field lens, 61, 62 ... Relay lens, 70 ... Second light modulator, 72r, 72g, 72b ... Liquid crystal panel, 73r, 73g, 73b ... Polarizing filter, 80 ... Cross dichroic prism, LB, LG, LR ... each color light, LLS ... common relay lens system, OA ... system optical axis

Claims (9)

A brightness modulation light valve that modulates the light from the lighting device;
A color separation optical system that separates the light whose luminance is modulated by the light valve for luminance modulation into first to third color light;
First to third color modulation light valves that respectively modulate the first to third color lights that have been luminance-modulated by the luminance modulation light valve and separated by the color separation optical system;
A common relay lens system that forms an image on the first and second color modulation light valves, respectively, with the first and second color lights modulated by the luminance modulation light valve and separated by the color separation optical system; A projector comprising:
The length of the optical path from the luminance modulation light valve to the first color modulation light valve is equal to the length of the optical path from the luminance modulation light valve to the second color modulation light valve,
Chromatic aberration correction for matching the imaging magnification of the first and second color lights by the shared relay lens system with at least one of the optical paths of the first and second color lights separated by the color separation optical system Projector with means. 2. The sub-relay lens system for forming an image on the third color modulation light valve with the third color light that has been luminance-modulated by the luminance modulation light valve and separated by the color separation optical system. projector The shared relay lens system temporarily forms an image of the third color light that has been subjected to luminance modulation by the luminance modulation light valve and separated by the color separation optical system,
The projector according to claim 1, further comprising a transfer optical system that re-images the third color light once imaged onto the third color modulation light valve. The chromatic aberration correcting means forms an image so that an image of a black matrix provided on the luminance modulation light valve is formed on a black matrix provided on at least one of the first and second color modulation light valves. The projector according to any one of claims 1 to 3, wherein the magnification is corrected. The chromatic aberration correcting means includes first and second optical elements respectively disposed on optical paths of the first and second color lights separated by the color separation optical system, and the first and second optical elements. The projector according to any one of claims 1 to 4, wherein the elements have different light collecting characteristics. First to third condenser lenses disposed opposite to the first to third color modulation light valves are provided, and the first and second condenser lenses among the first to third condenser lenses are provided. 6. The projector according to claim 5, wherein the optical lens corresponds to the first and second optical elements, and the curvature radii of the corresponding lens surfaces of the first and second condenser lenses are different from each other. The chromatic aberration correcting means includes first and second optical elements respectively disposed on optical paths of the first and second color lights separated by the color separation optical system,
First to third condenser lenses disposed opposite to the first to third color modulation light valves are provided, and the first and second condenser lenses among the first to third condenser lenses are provided. The optical lens corresponds to the first and second optical elements, and from the first and second condenser lenses to the first.
5. The projector according to claim 1, wherein the distances to the second color modulation light valve are different from each other. First to third condenser lenses disposed opposite to the first to third color modulation light valves are provided, and the first and second condenser lenses among the first to third condenser lenses are provided. The projector according to claim 5, wherein the optical lens corresponds to the first and second optical elements and has different refractive indexes. A light combining optical system that combines image light that is color-modulated by the first to third color modulation light valves; and a projection optical system that projects the combined light combined by the light combining optical system as image light. The projector according to any one of claims 1 to 8.

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