JPH10304284A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow effective use of a light from a light source, and to simultaneously project two systems of pictures by separating the light from the light source to S polarization and P polarization, reflecting the S polarization and the P polarization to first and second liquid crystal panels arranged at each destination, synthesizing the reflected light fluxes on a common optical path, and projecting it through a projection optical system. SOLUTION: A light from a light source 11 is separated into P polarization and S polarization by a polarization beam splitter 13. The P polarization and the S polarization are reflected through cross dichroic mirrors 14 and 19 by liquid crystal panels 15-17 and 20-22 for R, B, G, and transmitted to a polarization beam splitter. Then, S polarization components and P polarization components in the reflected lights from the mirrors 14 and 19 form a projected picture through the polarization beam splitter 13 and a projection optical system 24 on a screen. Thus, the projected picture for right and left eyes are formed of the P and S polarization components on the screen, and a stereoscopic picture can be viewed with spectacles for stereoscopic vision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector using a reflection type liquid crystal panel, and more particularly to a liquid crystal projector capable of simultaneously projecting two systems of images based on at least one light source.

[0002]

2. Description of the Related Art Conventionally, there has been known a reflection type liquid crystal projector which irradiates a liquid crystal panel with light from a light source and projects reflected light from the liquid crystal panel onto a screen. FIG. 9 is a diagram showing this type of liquid crystal projector. In FIG. 9, a polarizing beam splitter 83 is arranged in an irradiation direction of a light source 81 via an illumination optical system 82. A cross dichroic mirror 83a is arranged in the reflection direction of the polarization beam splitter 83.

In the cross dichroic mirror 83a, an R liquid crystal panel 84 is arranged in the reflection direction of the red component (R), and a B liquid crystal panel 85 is arranged in the reflection direction of the blue component (B). In addition, a G liquid crystal panel 86 is arranged in the transmission direction of the green component (G) in the cross dichroic mirror 83a. A drive voltage is applied to the electrodes of these liquid crystal panels 84 to 86 via a liquid crystal drive section 87.

On the other hand, reflected light beams generated by the liquid crystal panels 84 to 86 are combined into three colors via a cross dichroic mirror 83 a, and then emitted toward a polarization beam splitter 83. A projection optical system 8 is provided on an extension of this emission direction.
8 are arranged. In the conventional example having such a configuration, the light source 8
The light from No. 1 is split into S-polarized light and P-polarized light via the polarizing beam splitter 83. The branched S-polarized light enters the cross dichroic mirror 83a.

In the cross dichroic mirror 83a,
The S-polarized light is color-separated into light components of RGB, and is applied to panel surfaces of the liquid crystal panels 84 to 86, respectively. In each of the pixel sections on each of the liquid crystal panels 84 to 86, the arrangement of the liquid crystal molecules changes between a random state and an aligned state according to a voltage application state from the liquid crystal driving section 87.

In the random state, incident light is diffusely reflected by the axes of liquid crystal molecules being randomly oriented. At this time, since the depth and direction in which the incident light is reflected are not constant depending on the microscopic incident position, the wavefronts of the diffused light are complicatedly mixed and become in a non-polarized state. On the other hand, in the aligned state, S-polarized light is transmitted as it is because the axis of the liquid crystal molecules is oriented perpendicular to the panel surface. The S-polarized light transmitted in this manner is uniformly mirror-reflected on the back surface side of each of the liquid crystal panels 84 to 86, and thus becomes a reflected light maintaining the S-polarized state.

[0007] The reflected light beams of three colors generated in the liquid crystal panels 84 to 86 pass through the cross dichroic mirror 83 a to be combined into three colors, and then travel to the polarization beam splitter 83. In the polarization beam splitter 83, only the P-polarized component of the reflected light beam passes and reaches the projection optical system 88.

[0008] Therefore, in the pixel where the liquid crystal molecules are aligned, the reflected S-polarized light does not pass, and the corresponding color component light is lost. On the other hand, for a pixel in which liquid crystal molecules are in a random state, almost half of the P-polarized light component passes through the polarizing beam splitter 83 to generate diffused light in a non-polarized state. The P-polarized light component of the diffused light that has passed in this way is projected through the projection optical system 88 to form a projected image.

[0009]

By the way, in such a conventional example, of the irradiation light generated by the light source 81, the straight light (P-polarized light) passing through the polarizing beam splitter 83 is discarded. Therefore, there is a problem that not only the lighting power of the light source 81 is wastefully consumed, but also the temperature inside the device increases due to the discarded light.

In order to solve the above-mentioned problems, the invention according to claim 1 provides a liquid crystal projector capable of simultaneously projecting two systems of images while effectively utilizing light from a light source. The purpose is to: An object of the present invention is to provide a liquid crystal projector capable of projecting a stereoscopic image (so-called 3D image) using parallax between the left and right eyes, in addition to the object of the first embodiment. I do.

A third object of the present invention is to provide a liquid crystal projector capable of projecting a higher-resolution image, in addition to the object of the first embodiment. An object of the fourth aspect is to provide a liquid crystal projector capable of simultaneously projecting two systems of images while effectively utilizing light from a light source, as in the first aspect.

According to the fifth and sixth aspects of the present invention, the fourth aspect is provided.
It is another object of the present invention to provide a liquid crystal projector that facilitates an adjustment operation for two projection optical systems (described later). A seventh object of the present invention is to provide a liquid crystal projector capable of projecting a color image with high color reproducibility, in addition to the object of the first embodiment.

[0013]

FIG. 1 is a diagram for explaining the invention according to the first to third aspects of the present invention. According to the first aspect of the present invention, a light source 1, a polarization splitting unit 2 for splitting light from the light source 1 into S-polarized light and P-polarized light, and a destination of the S-polarized light split by the polarization splitting unit 2 are arranged. A first liquid crystal panel 3 that modulates and reflects the polarization state of the S-polarized light in accordance with a first image signal given from the outside, A second liquid crystal panel 4 that modulates and reflects the polarization state of the P-polarized light in accordance with a second image signal given by the first and second liquid crystal panels 3 and 4 And a projection optical system 5 that is arranged on an optical path that passes commonly after passing through and that projects incident light.

According to a second aspect of the present invention, in the liquid crystal projector according to the first aspect, the first liquid crystal panel 3 comprises:
The S-polarized light is modulated into an S-polarized state and a non-polarized state in accordance with an externally applied right (or left) eye image signal and reflected. (Or right) The P-polarized light is modulated into a P-polarized state and a non-polarized state according to an image signal for the eye and reflected, and the projection optical system 5 forms an image of incident light on a screen surface. It is characterized by.

According to a third aspect of the present invention, in the liquid crystal projector according to the first aspect, the first liquid crystal panel 3 and the second liquid crystal panel 4 are arranged such that the pixel arrangement on the panels is spatially shifted from each other. It is characterized by becoming. According to the fourth aspect of the present invention, the light source 1 and the light from the light source 1
Polarization splitting means 2 for splitting the light into polarized light; and a polarization splitting means 2 disposed at a destination of the S-polarized light split by the polarization splitting means 2 and modulating the polarization state of the S-polarized light in accordance with a first image signal supplied from outside. The first liquid crystal panel 3 that reflects light and the P-polarized light branched by the polarization splitting means 2 are arranged at the destination, and the polarization state of the P-polarized light is modulated and reflected according to a second image signal supplied from the outside. A second liquid crystal panel 4, a first projection optical system disposed on the reflected light path of the first liquid crystal panel 3, and extracting and projecting a P-polarized component from the reflected light beam; It is arranged on the reflected light path, and S
A second projection optical system for extracting and projecting a polarized light component.

According to a fifth aspect of the present invention, in the liquid crystal projector according to the fourth aspect, the first projection optical system and the second
And the projection optical system of (1) is provided with an angle-of-view interlocking mechanism for interlocking both angle-of-view changes. According to a sixth aspect of the present invention, in the liquid crystal projector according to the fourth aspect, the first projection optical system and the second projection optical system
It is characterized by having a focus interlocking mechanism for interlocking both focus movements.

According to a seventh aspect of the present invention, in the liquid crystal projector according to any one of the first to sixth aspects,
The first and second liquid crystal panels 3 and 4 are provided with polarization splitting means 2.
And a reflection type liquid crystal panel arranged for each of the colored light beams color-separated by the color separation optical means.

(Function) In the liquid crystal projector of the first aspect, the polarization splitting means 2 converts the irradiation light from the light source 1 into S-polarized light and P-polarized light.
Split into polarized light. The branched S-polarized light is applied to the first liquid crystal panel 3, and the branched P-polarized light is applied to the second liquid crystal panel 4. At this time, in the first liquid crystal panel 3,
The incident light is reflected while being modulated in accordance with the polarization state of the first image signal. At this time, for the S-polarized component of the reflected light,
The light travels backward along the incident path of the polarization splitting means 2 and returns to the light source 1 side.
On the other hand, for the P-polarized component of the reflected light,
Through a specific direction other than the light source 1.

On the other hand, the second liquid crystal panel 4 reflects while modulating the incident polarization state in accordance with the second image signal.
Of the reflected light generated by the second liquid crystal panel 4 as described above, P
With respect to the polarized light component, the light travels backward through the incident path of the polarization splitting means 2 and returns to the light source 1 side. On the other hand, the S-polarized light component is emitted in a specific direction other than the light source 1 via the polarization splitting means 2.

As described above, the “first liquid crystal panel 3
P-polarized light component of reflected light generated by the second liquid crystal panel 4 "
The S-polarized light component of the reflected light generated in step (1) passes through the polarization splitting means 2 and is combined into one. The projection optical system 5 projects the combined light to form a projection image. According to the above-described operation, the liquid crystal projector according to the first aspect simultaneously projects images based on two types of image signals (a first image signal and a second image signal).

In the liquid crystal projector according to the second aspect, the first liquid crystal panel 3 is provided with a right (or left) externally supplied.
The arrangement of the liquid crystal molecules is changed in pixel units according to the image signal for eyes. Here, when the axes of the liquid crystal molecules are oriented perpendicular to the panel surface, the reflected light is reflected while maintaining the S-polarized state. On the other hand, when the axes of the liquid crystal molecules are randomly aligned, the reflected light becomes unpolarized diffused light.

On the other hand, also in the second liquid crystal panel 4, the arrangement of liquid crystal molecules is changed in pixel units according to an externally applied left (or right) image signal. here,
When the axes of the liquid crystal molecules are oriented perpendicular to the panel surface, the reflected light is reflected while maintaining the P-polarized state. On the other hand, when the axes of the liquid crystal molecules are randomly aligned, the reflected light becomes unpolarized diffused light.

Accordingly, the projection optical system 5 includes both the “P-polarized light component of the diffused light generated in the first liquid crystal panel 3” and the “S-polarized light component of the diffused light generated in the second liquid crystal panel 4”. Incident on. The projection optical system 5 forms an image of the diffused light to form a projection image on a screen surface.

By such an operation, a projected image for the right (or left) eye is formed on the screen surface by the P-polarized component, and a projected image for the left (or right) eye is formed by the S-polarized component. You. Here, when the above-described multiple images are viewed with stereoscopic glasses using a polarizing plate as shown in FIG. 3, a stereoscopic image based on parallax between the left and right eyes is reproduced.

In the liquid crystal projector according to the second aspect, since the stereoscopic image is observed through the glasses for stereoscopic vision, the brightness of the image perceived by the observer is reduced to about half of the brightness on the screen. Therefore, in the stereoscopic image, in order to ensure “the same brightness and contrast as a normal projected image”, it is necessary to pass one projection optical system 5 through about twice the amount of light.

When the light amount is increased for such a reason, since the left and right projection light passes through the inside of the projection optical system 5, the inside of the barrel of the projection optical system 5 becomes extremely hot. Will cause a problem. However, in the liquid crystal projector according to the second aspect, all of the light passing through the projection optical system 5 is diffused light, and problems such as a rise in temperature are unlikely to occur. Therefore, in projecting a bright stereoscopic image, the liquid crystal projector according to claim 2 has a preferable configuration.

In the liquid crystal projector of the third aspect, the pixel arrangement of the first liquid crystal panel 3 and the pixel arrangement of the second liquid crystal panel 4 are arranged in a state where they are mutually shifted by spatial pixels. Normally, when the phases of the pixel arrays are aligned in the first and second liquid crystal panels 3 and 4, the resolution of the projected image is the same as that of the conventional liquid crystal panel alone. However, when the spatial pixel shift is performed as described above, the light spot on the screen projected by one pixel is
The light spots projected by the other pixels are shifted and overlap. At this time, the luminance distribution within a single pixel is subdivided by the number of overlapping patterns of light spots, so that the display resolution or gradation of the projected image is improved.

Conventionally, when a transparent electrode or the like is arranged at a boundary between pixels on a liquid crystal panel, a boundary line between pixels of a projected image may be conspicuous. However, when the spatial pixel shift is performed as described above, the boundary generated between the pixels overlaps with the other pixel and becomes inconspicuous. As a result, the image quality of the projected image is also improved. In the liquid crystal projector according to the fourth aspect, the polarization splitting means 2 splits the light from the light source 1 into S-polarized light and P-polarized light.

The S-polarized light thus branched reaches the first liquid crystal panel 3 and is reflected. At this time, the first liquid crystal panel 3 modulates the polarization state of the reflected light according to the first image signal. The first projection optical system extracts the P-polarized component of the reflected light modulated as described above and projects it to the outside.

On the other hand, the branched P-polarized light reaches the second liquid crystal panel 4 and is reflected. At this time, the second liquid crystal panel 4 modulates the polarization state of the reflected light according to the second image signal. The second projection optical system extracts the S-polarized component of the reflected light modulated as described above, and projects the extracted S-polarized component to the outside. According to the above-described operation, the liquid crystal projector according to the fourth aspect can simultaneously project two types of projection images based on at least one light source 1.

In such a configuration, by aligning the projection directions of the two projection optical systems, images of two systems can be displayed in an overlapping manner. Further, by shifting the projection directions of the two projection optical systems, it is also possible to display two images in parallel. Further, by individually setting the angles of view of the two projection optical systems, it is possible to individually change the sizes of the two systems of images.

The liquid crystal projector according to the fifth aspect has an angle-of-view interlocking mechanism that changes the angle of view of the first projection optical system and the angle of view of the second projection optical system in an interlocking manner. The liquid crystal projector according to the sixth aspect has a focus interlocking mechanism that changes the focus state of the first projection optical system and the focus state of the second projection optical system in an interlocked manner. In the liquid crystal projector according to claim 7,
After splitting the irradiation light in the polarization splitting means 2, two color separation optical means for performing color separation are arranged. A reflection type liquid crystal panel is arranged for each of the colored luminous fluxes color-separated by these color separation optical means.

In such an arrangement of the optical system, light incident on each color separation optical means is limited to linearly polarized light. Therefore, it is not necessary to consider the difference in the color separation characteristics between the S-polarized light and the P-polarized light in each color separation optical unit. Therefore, each color separation optical unit can obtain good color separation characteristics specialized for linearly polarized light.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 2 is a diagram showing a first embodiment (corresponding to claims 1, 2, and 7). In FIG. 2, an illumination optical system 12
, The polarization beam splitter 13 is disposed. A cross dichroic mirror 14 is arranged in the transmission direction of the polarization beam splitter 13.

In the direction of reflection of the red component (R) on the cross dichroic mirror 14, the R liquid crystal panel 1
5, and a liquid crystal panel 16 for B is arranged in the reflection direction of the blue component (B). Further, in the transmission direction of the green component (G) in the cross dichroic mirror 14,
Liquid crystal panel 17 is arranged. These liquid crystal panels 1
A drive voltage is applied to the electrodes 5 to 17 via the liquid crystal drive unit 18.

On the other hand, a cross dichroic mirror 19 is arranged in the reflection direction of the polarization beam splitter 13. An R liquid crystal panel 20 is arranged in the direction of reflection of the red component (R) on the cross dichroic mirror 19, and a B liquid crystal panel 21 is arranged in the direction of reflection of the blue component (B). In addition, a G liquid crystal panel 22 is arranged in the transmission direction of the green component (G) in the cross dichroic mirror 19.

A drive voltage is applied to the electrodes of the liquid crystal panels 20 to 22 via a liquid crystal drive unit 23. The reflected light fluxes from these liquid crystal panels 20 to 22 are synthesized through the cross dichroic mirror 19 into three colors,
The light is emitted toward the polarization beam splitter 13. The projection optical system 24 is disposed on an extension of the emission direction.

As to the correspondence between the first and second embodiments of the present invention, the light source 1 corresponds to the light source 11, the polarization splitter 2 corresponds to the polarization beam splitter 13, and The liquid crystal panel 3 includes a cross dichroic mirror 19, liquid crystal panels 20 to 22, and a liquid crystal driving unit 23.
, The second liquid crystal panel 4 includes a cross dichroic mirror 14, liquid crystal panels 15 to 17, and a liquid crystal driving unit 1.
8, and the projection optical system 5 corresponds to the projection optical system 24.

In the correspondence between the invention described in claim 7 and the first embodiment, the color separation optical means corresponds to the cross dichroic mirrors 14 and 19, and the reflection type liquid crystal panel is the liquid crystal panels 15 to 17 and the liquid crystal panel. Corresponds to panels 20-22. Hereinafter, the operation of the first embodiment will be described. First, light from the light source 11 is split into S-polarized light and P-polarized light via the polarization beam splitter 13. The branched S-polarized light enters the cross dichroic mirror 19. On the other hand, the P-polarized light after splitting is cross-dichroic mirror 1
4 is incident.

The cross dichroic mirror 19 separates the incident S-polarized light into light of RGB and irradiates the liquid crystal panels 20 to 22 respectively. The liquid crystal drive unit 23
The voltage application state of each of the liquid crystal panels 20 to 22 is changed for each pixel section according to the image signal for the right eye. For example, in a pixel in which alignment of liquid crystal molecules is in a random state, incident light is diffusely reflected. At this time, since the depth and direction in which the incident light is reflected are not constant depending on the microscopic incident position, the wavefronts of the diffused light are complicatedly mixed and become in a non-polarized state.

In a pixel in which liquid crystal molecules are aligned, reflected light is maintained while maintaining the S-polarized state. In this way, reflected light beams of three colors are generated in each of the liquid crystal panels 20 to 22. The reflected light beams of these three colors are combined via the cross dichroic mirror 19 and then travel to the polarization beam splitter 13.

At this time, in the polarization beam splitter 13, only the P-polarized light component of the reflected light beam passes. Therefore, for the pixels in which the liquid crystal molecules are aligned in the liquid crystal panels 20 to 22, the reflected S-polarized light is blocked by the polarization beam splitter 13, and the corresponding color component light is lost.

In a pixel in which liquid crystal molecules are in a random state, almost half of the P-polarized light component passes through the polarizing beam splitter 13 because diffused light in a non-polarized state is generated. The P-polarized component of the diffused light that has passed in this way is imaged via the projection optical system 24 and
A projected image composed of P-polarized light is formed on a screen disposed at a position optically conjugate with the light-emitting elements 22 to 22.

On the other hand, the P-polarized light that has entered the cross dichroic mirror 14 is color-separated into light of RGB, and is applied to each of the liquid crystal panels 15 to 17. The liquid crystal driving section 18 controls each liquid crystal panel 1 according to the image signal for the left eye.
The voltage application states of 5 to 17 are changed for each pixel section.
As a result, the arrangement of the liquid crystal molecules is in a random state or an aligned state for each pixel section.

In the random state, since the axes of the liquid crystal molecules are randomly oriented, the non-polarized state diffused light is reflected. On the other hand, in the aligned state, the incident P-polarized light is reflected as it is because the axes of the liquid crystal molecules are oriented perpendicular to the panel surface. The three color reflected light beams generated in each of the liquid crystal panels 15 to 17 are transmitted to the cross dichroic mirror 1.
4, the polarization beam splitter 13
Head for.

At this time, the polarization beam splitter 13 reflects only the S-polarized light component of the reflected light beam. Therefore, for the pixels in which the liquid crystal molecules are aligned in the liquid crystal panels 15 to 17, the reflected P-polarized light is not reflected by the polarization beam splitter 13, and the corresponding color component light is lost.

On the other hand, for a pixel in which liquid crystal molecules are in a random state, almost half of the S-polarized component is reflected via the polarizing beam splitter 13 because diffused light in a non-polarized state is generated. The S-polarized component of the diffused light reflected in this way forms an image via the projection optical system 24, and the liquid crystal panel 1
A projection image composed of S-polarized light is formed on a screen arranged at a position optically conjugate with 5 to 17.

According to the above-described operation, in the first embodiment, a projection image for the right eye is formed on the screen surface by the P polarization component, and a projection image for the left eye is formed by the S polarization component. Here, a stereoscopic image based on binocular parallax can be viewed by wearing stereoscopic glasses using a polarizing plate as shown in FIG. 3 and observing the multiple images as described above.

Furthermore, in the first embodiment, unlike the conventional example (FIG. 9), almost half of the light from the light source is not wasted. Therefore, the lighting power of the light source can be more effectively used. In addition, problems such as an increase in the temperature inside the device due to uselessly discarded light can be solved. As a result, the size of the cooling mechanism such as the blower fan can be reduced, and the power required for the cooling mechanism can be reduced.

Further, in the first embodiment, since the diffused light is imaged in the projection optical system 24, unlike in the case of the Schlieren optical system, one point of light is not concentrated inside the optical system. Therefore, problems such as a local rise in the temperature on the optical path do not occur. In the first embodiment described above, the image for the right eye is formed by P-polarized light, and the image for the left eye is formed by S-polarized light.
The polarization directions of both images may be reversed. Generally, it is sufficient that the polarization directions of the left and right images are set in accordance with the left and right of the polarizing plate in the stereoscopic glasses.

Next, another embodiment will be described. (Second Embodiment) FIG. 4 shows a second embodiment (Claim 3).
FIG. Referring to FIG.
A polarization beam splitter 33 is arranged via an illumination optical system 32 in the irradiation direction. A liquid crystal panel 34b is arranged in the transmission direction of the polarization beam splitter 33, and a liquid crystal panel 34a is arranged in the reflection direction. These liquid crystal panels 34a and 34b are arranged at mirror positions with the optical thin film in the polarizing beam splitter 33 being symmetrical. At this time, the corresponding pixel sections of the liquid crystal panels 34a and 34b are arranged so as to be shifted by a half pixel in the oblique direction as shown in FIG.

Further, the polarization beam splitter 33 is inserted in the middle, and the projection optical system 3 is disposed on the side facing the liquid crystal panel 34a.
5 are arranged. The drive electrode of the liquid crystal panel 34a is connected to the sample section 37a via the liquid crystal drive section 36a. The sample unit 37a is connected to the frame memory 3 via the data bus 38.
9 is connected.

The drive electrode of the liquid crystal panel 34b is connected to the half-pixel shift sample section 37b via the liquid crystal drive section 36b. The half-pixel shift sample section 37b is connected to the data bus 38.
Is connected to the frame memory 39 via the. Image signals are sequentially written into the frame memory 39 via the image processing unit 40.

The light source 1 shown in FIG. 1 corresponds to the light source 31, and the polarization splitter 2 corresponds to the polarization beam splitter 33 in the third embodiment and the second embodiment. The first liquid crystal panel 3 is a liquid crystal panel 34a.
, The second liquid crystal panel 4 corresponds to the liquid crystal panel 34b, and the projection optical system 5 corresponds to the projection optical system 35.

The operation of the second embodiment will be described below.
First, the image processing unit 40 sequentially captures an image signal of high resolution (double the vertical and horizontal resolution of the liquid crystal panel 34 a) from the outside, performs A / D conversion, inverse γ conversion, and the like, and then sequentially stores the image signal in the frame memory 39. Write. The sample section 37a and the half-pixel shift sample section 37b alternately access the frame memory 39 via the data bus 38.

The sampling section 37a averages the image signal in the frame memory 39 for each (2 × 2) pixel section (hereinafter, such a pixel operation is referred to as “re-sampling”). By such resampling, an image signal that matches the resolution of the liquid crystal panel 34a is obtained. The liquid crystal driving unit 36a responds to the image signal resampled in this way and
A drive voltage is applied to a.

The half-pixel shift sample section 37b selects a (2 × 2) pixel section which is obliquely shifted by a half phase with respect to the sampling phase of the sample section 37a, and resamples the image signal in the frame memory 39. Perform the conversion. By such resampling, an image signal that matches the resolution of the liquid crystal panel 34b is
It is obtained in a state shifted by half a pixel from the liquid crystal panel 34a side. The liquid crystal driver 36b applies a drive voltage to the liquid crystal panel 34b according to the image signal resampled in this way.

These liquid crystal panels 34a and 34b include:
Light from the light source 31 is irradiated via the polarizing beam splitter 33. The liquid crystal panels 34a and 34b respectively modulate the reflected light according to the drive voltage. The reflected light modulated in this way is combined when returning from the polarization beam splitter 33, and reaches the projection optical system 35. Projection optical system 35
Project this combined light onto a screen.

FIG. 6B is an example of a projected image modulated on the liquid crystal panel 34a. On the other hand, FIG.
Is an example of a projection image modulated on the liquid crystal panel 34b. These projection images are superimposed on the screen to display a projection image as shown in FIG.

As described above, by overlapping the two systems of projected images with a shift of half a pixel, pixel sections showing the same luminance (the same color) are subdivided, and the display resolution or gradation of the projected images is improved. As a result, as shown in FIG. 6D, the edge portion of the image can be displayed more smoothly.

Further, in a flat portion of the image, the brightness of the projected image is doubled by overlapping the two types of projected images, and a brighter projected image can be displayed. Furthermore, the boundary between the pixels of the liquid crystal panels 34a and 34b overlaps the other pixel and becomes inconspicuous, so that a higher quality projected image can be displayed. In the above-described second embodiment, the spatial pixels are shifted obliquely, but the present invention is not limited to this. For example, spatial pixels may be shifted in the vertical or horizontal direction.

In the above-described second embodiment, each of the liquid crystal panels 34a and 34b is formed of a single plate, but is not limited to this structure. Each of the liquid crystal panels 34a and 34b may be replaced with a “block composed of a dichroic mirror and a multi-panel liquid crystal panel”. In this case, each color component light (for example, RG
As for B), spatial pixel shift can be performed together, so that higher resolution can be achieved.

Further, in the above-described second embodiment, an image signal to be supplied to the liquid crystal panels 34a and 34b is newly generated based on an image signal having twice the vertical and horizontal resolution. However, the present invention is not limited to this. Not something. For example, an image signal taken in from the outside may be displayed on the liquid crystal panel 34a as it is, and an "image signal shifted by half a pixel" obtained by pixel interpolation of the image signal may be displayed on the liquid crystal panel 34b. Even with such a display operation, it is possible to smoothly display an edge portion or the like of an image.

Next, another embodiment will be described. (Third Embodiment) FIG. 7 shows a third embodiment (Claim 4).
7 (corresponding to ７7). In FIG. 7, a polarizing beam splitter 53a is arranged in the irradiation direction of the light source 51 via an illumination optical system 52. Further, a cross dichroic mirror 54 is disposed in the transmission direction of the polarization beam splitter 53a via the polarization beam splitter 53b.

The direction of reflection of the red component (R) on the cross dichroic mirror 54 is
5, and a B liquid crystal panel 56 is arranged in the reflection direction of the blue component (B). Further, in the transmission direction of the green component (G) in the cross dichroic mirror 54, G
Liquid crystal panel 57 is arranged. These liquid crystal panels 5
A drive voltage is applied to the electrodes 5 to 57 via the liquid crystal drive unit 58.

The reflected light fluxes from the liquid crystal panels 55 to 57 are combined by the cross dichroic mirror 54 into three colors, and then reflected by the polarization beam splitter 53b. On the extension of the reflection direction, the projection optical system 6
4b is arranged. On the other hand, the polarization beam splitter 53a
A cross dichroic mirror 59 is disposed in the reflection direction of.

The direction of reflection of the red component (R) on the cross dichroic mirror 59 corresponds to the R liquid crystal panel 6.
0 is arranged, and the B liquid crystal panel 61 is arranged in the reflection direction of the blue component (B). Further, in the transmission direction of the green component (G) in the cross dichroic mirror 59, G
Liquid crystal panel 62 is arranged.

A drive voltage is applied to the electrodes of these liquid crystal panels 60 to 62 via a liquid crystal drive section 63. The reflected light fluxes from these liquid crystal panels 60 to 62 are combined through the cross dichroic mirror 59 into three colors, and then combined.
The light is emitted toward the polarization beam splitter 53a. A projection optical system 64a is arranged on the extension of the emission direction.

The same rotational drive is transmitted via the interlocking mechanism 65 between the extension cam (not shown) of the projection optical system 64a and the extension cam (not shown) of the projection optical system 64b. . As a result, the lens group for adjusting the angle of view in the projection optical system 64a and the lens group for adjusting the angle of view in the projection optical system 64b move back and forth together. Further, the projection optical system 6
The lens group for focus adjustment in 4a and the lens group for focus adjustment in the projection optical system 64b move back and forth together.

The interlocking mechanism 65 is provided with a clutch structure or the like at a part of the transmission path of the rotational drive.
By the pressing operation a, the transmission of the rotational drive is temporarily released. The polarization beam splitter 53a and the cross dichroic mirror 59 are fixed on a base 52b, and the base 52b slides on the tilt rail 52a.

Further, the polarization beam splitter 53b and the cross dichroic mirror 54 are fixed on a base 52d, and the base 52d slides on a tilt rail 52c. As for the correspondence between the invention described in claim 4 and the third embodiment, the light source 1 corresponds to the light source 51, the polarization splitting means 2 corresponds to the polarization beam splitter 53a, and the first liquid crystal panel 3 Corresponds to the cross dichroic mirror 59 and the liquid crystal panels 60 to 62, the second liquid crystal panel 4 corresponds to the cross dichroic mirror 54 and the liquid crystal panels 55 to 57, and the first projection optical system includes the polarization beam splitter 53a and the projection optical system. The second projection optical system corresponds to the polarization beam splitter 53b and the projection optical system 64b.

As for the correspondence between the invention described in claim 5 and the third embodiment, the view angle interlocking mechanism corresponds to the interlocking mechanism 65. Regarding the correspondence between the invention described in claim 6 and the third embodiment, the focus interlocking mechanism corresponds to the interlocking mechanism 65. Regarding the correspondence between the invention described in claim 7 and the third embodiment, the color separation optical means corresponds to the cross dichroic mirrors 54 and 59, and the reflection type liquid crystal panels are the liquid crystal panels 55 to 57 and the liquid crystal panels 60 to 60. 62.

The operation of the third embodiment will be described below.
The irradiation light from the light source 51 is split into S-polarized light and P-polarized light by the polarization beam splitter 53a. The branched S-polarized light is applied to the liquid crystal panels 60 to 62 via the cross dichroic mirror 59. These liquid crystal panels 60 to
The reflected light generated at 62 arrives at the polarization beam splitter 53a by following the incident path in reverse. In the polarization beam splitter 53a, only the P-polarized light component of the reflected light goes straight. The projection optical system 64a projects the P-polarized light and displays a projection image composed of the P-polarized light component on a screen.

On the other hand, the P-polarized light component of the light emitted from the light source 51 is
The beam goes straight through the polarization beam splitter 53a and the polarization beam splitter 53b. The P-polarized component is applied to the liquid crystal panels 55 to 57 via the cross dichroic mirror 54. The reflected light generated by these liquid crystal panels 55 to 57 reverses the incident path and travels through the polarization beam splitter 53.
reaches b. The polarization beam splitter 53b reflects only the S-polarized light component of the reflected light. Projection optical system 64b
Projects the S-polarized light and displays a projected image composed of the S-polarized component on a screen.

With such an operation, two systems of projected images are displayed on the screen using the two-lens projection optical systems 64a and 64b. Here, as shown in FIG.
By making the display positions of the two systems of projected images substantially coincide with each other, a projected image for stereoscopic vision can be displayed as in the first embodiment. At this time, by operating the interlocking mechanism 65, the angle of view of the projection optical systems 64a and 64b can be adjusted at a time. Further, by operating the interlocking mechanism 65, the focus adjustment of the projection optical systems 64a and 64b can be performed at once.

Also, as shown in FIG. 8C, two types of projected images can be displayed in parallel by shifting the display positions of the two systems of projected images. In such a side-by-side display, the bases 52b and 52d are connected to the tilting rails 52a,
It can be realized by shifting to the left and right along 52c. At this time, the projection optical systems 64a and 64b can be individually adjusted by pressing the linkage release button 65a to release the linkage of the linkage mechanism 65.

In the first to third embodiments described above,
The liquid crystal panel is binary-modulated between a random state and an aligned state, but is not limited to this. For example,
By applying an intermediate voltage to the electrodes of the liquid crystal panel, an intermediate state in which the random state and the aligned state are mixed may be provided. By such multi-level modulation, it is possible to increase the gradation of the projected image and increase the number of display colors.

The duty ratio may be changed according to the image signal while repeating the above-mentioned binary modulation at a high speed. By such PWM modulation (pulse width modulation),
It is possible to increase the gradation of the projected image and increase the number of display colors.

[0080]

As described above, according to the first aspect of the present invention, the first and second liquid crystal panels are irradiated with the light from the light source via the polarization splitting means. The reflected light generated in each of these liquid crystal panels is recombined via a polarization splitting unit, and then projected via a projection optical system.

Therefore, two systems of projected images can be simultaneously projected using at least one light source. As a result, the light of the light source is not wasted, and the lighting power of the light source can be effectively used. Further, problems such as an increase in the temperature inside the device due to uselessly discarded light can be improved.

According to the second aspect of the present invention, the projection image for the right (or left) eye is formed by the P-polarized light component, and the projection image for the left (or right) eye is formed by the S-polarized light component. Therefore, a stereoscopic image based on binocular parallax can be displayed for an observer wearing stereoscopic glasses. By the way, in order to compensate for the multiple of exposure of the stereoscopic glasses, it is necessary to pass about twice the amount of light through the projection optical system. In this case, since the left and right projection light intensively pass through one projection optical system, a problem such as a temperature rise occurs. In particular, when a schlieren optical system or the like is employed as the projection optical system, all the projection lights are concentrated at one point on the optical path, and a local and extreme temperature rise occurs.

However, in the liquid crystal projector according to the second aspect, all of the light passing through the projection optical system is diffused light, so that problems such as a rise in temperature are unlikely to occur. Therefore, in projecting a bright stereoscopic image, the liquid crystal projector according to claim 2 has a particularly preferable configuration. According to the third aspect of the present invention, the pixel arrangement of the first liquid crystal panel and the pixel arrangement of the second liquid crystal panel are arranged so as to be shifted from each other by spatial pixels. Therefore, it is possible to increase the resolution or gradation of the projected image by subdividing the pixel sections having the same luminance. In particular, it is possible to smoothly and naturally display an edge portion and the like of the projection image.

Further, in a flat portion of the image, the brightness of the projected image is doubled by overlapping the two types of projected images, and a bright projected image can be displayed. Furthermore, the boundary line displayed between the pixels also overlaps with the other pixel and becomes inconspicuous, so that a more natural projected image can be displayed.

According to the fourth aspect of the present invention, at least one
Two systems of images are simultaneously projected based on two light sources. As a result, the light of the light source is not wasted, and the lighting power of the light source can be effectively used. Further, problems such as an increase in the temperature inside the device due to uselessly discarded light can be improved.

In particular, in such a configuration, two systems of images can be displayed in parallel by shifting the projection directions of the two projection optical systems. In the invention according to claim 5,
The angle of view of the first projection optical system and the angle of view of the second projection optical system are linked. Therefore, the angle of view of the two projection optical systems can be adjusted at once, and the operability of the liquid crystal projector can be further improved.

In the invention according to claim 6, the focus state of the first projection optical system and the focus state of the second projection optical system are linked. Therefore, the focus of the two projection optical systems can be adjusted at once, and the operability of the liquid crystal projector can be further improved. According to the seventh aspect of the present invention, since the light incident on each color separation optical means is limited to linearly polarized light, a difference in color separation characteristics due to a difference in polarization plane can be ignored.

Therefore, in each color separation means,
Good color separation characteristics can be obtained by specializing the incident linearly polarized light. Therefore, in the liquid crystal projector having such a configuration, color separation and color synthesis of light are executed more accurately, and a color image with good color reproducibility can be displayed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the invention according to claims 1 to 3;

FIG. 2 is a diagram showing a first embodiment (corresponding to claims 1, 2, and 7);

FIG. 3 is a perspective view showing stereoscopic glasses.

FIG. 4 is a diagram showing a second embodiment (corresponding to claim 3);

FIG. 5 is a diagram for explaining spatial pixel shifting of a liquid crystal panel.

FIG. 6 is a diagram illustrating a display example according to the second embodiment in combination with a halftone image on a screen.

FIG. 7 is a diagram showing a third embodiment (corresponding to claims 4 to 7);

FIG. 8 is a diagram illustrating a use state of the third embodiment.

FIG. 9 is a diagram showing a conventional reflection type liquid crystal projector.

[Explanation of symbols]

 Reference Signs List 1 light source 2 polarization splitting means 3 first liquid crystal panel 4 second liquid crystal panel 5 projection optical system 11 light source 12 illumination optical system 13 polarization beam splitter 14 cross dichroic mirror 15 R liquid crystal panel 16 B liquid crystal panel 17 G liquid crystal Panel 18 Liquid crystal driving unit 19 Cross dichroic mirror 20 Liquid crystal panel for R 21 Liquid crystal panel for B 22 Liquid crystal panel for G 23 Liquid crystal driving unit 24 Projection optical system 31 Light source 32 Illumination optical system 33 Polarizing beam splitter 34a Liquid crystal panel 34b Liquid crystal panel 35 Projection Optical system 36a Liquid crystal drive unit 36b Liquid crystal drive unit 37a Sample unit 37b Half pixel shift sample unit 38 Data bus 39 Frame memory 40 Image processing unit 51 Light source 52 Illumination optical system 52a Rail for tilting 52b Base 52c Rail for tilting 52d Base 53a Polarizing beam splitter 53b Polarizing beam splitter 54 Cross dichroic mirror 55 Liquid crystal panel for R 56 Liquid crystal panel for B 57 Liquid crystal panel for G 58 Liquid crystal driving unit 59 Cross dichroic mirror 60 Liquid crystal panel for R 61 Liquid crystal panel for B 62 Liquid crystal panel for G 63 LCD drive unit 64a Projection optical system 64b Projection optical system 65 Interlocking mechanism 65a Interlock release button 81 Light source 82 Illumination optical system 83 Polarization beam splitter 83a Cross dichroic mirror 84 Liquid crystal panel for R 85 Liquid crystal panel for B 86 Liquid crystal panel for G 87 Liquid crystal drive Part 88 Projection optical system

Claims (7)

[Claims] A light source; a polarization splitting unit that splits light from the light source into S-polarized light and P-polarized light; A first liquid crystal panel that modulates and reflects the polarization state of the S-polarized light in accordance with the first image signal; and a second image that is disposed at the destination of the P-polarized light branched by the polarization branching unit and that is externally provided. A second liquid crystal panel that modulates and reflects the polarization state of the P-polarized light according to a signal; and an optical path through which reflected light beams from the first and second liquid crystal panels pass in common via the polarization splitting unit. A liquid crystal projector, comprising: a projection optical system arranged to project incident light. 2. The liquid crystal projector according to claim 1, wherein the first liquid crystal panel changes the S-polarized light into an S-polarized state according to an externally applied right (or left) eye image signal. The second liquid crystal panel modulates the P-polarized light into a P-polarized state and a non-polarized state according to an externally applied left (or right) eye image signal. And a projection optical system that forms an image of incident light on a screen surface. 3. The liquid crystal projector according to claim 1, wherein the first liquid crystal panel and the second liquid crystal panel are arranged such that pixel arrangements on the panels are mutually shifted by spatial pixels. LCD projector. 4. A light source; a polarization splitting unit that splits light from the light source into S-polarized light and P-polarized light; A first liquid crystal panel that modulates and reflects the polarization state of the S-polarized light in accordance with the image signal of the first, and a second liquid crystal panel that is disposed at the destination of the P-polarized light branched by the polarization branching means and provided from outside A second liquid crystal panel that modulates and reflects the polarization state of the P-polarized light in accordance with an image signal; and is disposed on a reflected light path of the first liquid crystal panel, and extracts and projects a P-polarized component from the reflected light flux. A first projection optical system, and a second projection optical system disposed on a reflection optical path of the second liquid crystal panel, for extracting and projecting an S-polarized component from the reflected light flux. LCD projector. 5. The liquid crystal projector according to claim 4, wherein the first projection optical system and the second projection optical system each include an angle-of-view interlocking mechanism that interlocks both angle-of-view changes. Characteristic liquid crystal projector. 6. The liquid crystal projector according to claim 4, further comprising a focus interlocking mechanism for interlocking the movement of the focal points of the first projection optical system and the second projection optical system. Liquid crystal projector. 7. The liquid crystal projector according to claim 1, wherein the first and second liquid crystal panels include a color separation optical unit that performs color separation of incident light from the polarization splitting unit. And a reflection type liquid crystal panel arranged for each of the colored light beams separated by the color separation optical means.