JPH07234380A - Projection display system for stereoscopic vision - Google Patents

Abstract

PURPOSE:To provide a polarization glasses system projection display system for stereoscopic vision capable of being used in a bright room and causing no cross-talk of two sets of videos provided with parallax even though provided with a reflection mirror in its optical path. CONSTITUTION:A polarizing plate 3 is arranged on a video projection optical unit 1 for left eye so that a plane of polarization becomes perpendicular to the incident surface of the reflection mirror 7, and the polarizing plate 4 is arranged on the video projection optical unit 2 for right eye so that the plane of polarization becomes parallel. Since a video beam 5 for left eye is made incident in the polarization direction perpendicular to the incident surface of the mirror 7, no polarization state of the reflected beam 8 is changed. Similarly, since the video beam 6 for right eye is made incident in the polarization direction parallel to the incident surface of the mirror 7, polarization state of the reflected beam 9 is not changed. The reflected beams 8, 9 arrive at a transmission type screen 10, and an observer separation observes the videos with parallax of the beams 8, 9 by the polarizing plates 12, 13 attached to glasses 11, and the observer recognizes a stereoscopic video without cross-talk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic projection display system capable of easily obtaining a large-screen stereoscopic image.

[0002]

2. Description of the Related Art Conventionally, various display systems capable of stereoscopic viewing have been proposed, and FIG. 7 is a block diagram of a conventional front type projection display system for stereoscopic viewing. In the figure, reference numerals 1 and 2 denote optical units including an image source and a projection lens, and polarizing plates 3 and 4 having polarization directions orthogonal to each other are attached to each projection lens. The image projected at this time is a different image with an arbitrary parallax, and the optical unit 1 corresponds to the left eye and 2 corresponds to the right eye. The observer observes the image projected on the reflective screen 14 using the polarized glasses 11. Left eye 1 of polarized glasses 11
2 has the same polarization direction as the optical unit 1 for the left eye, and 1 for the right eye.
A polarizing plate having the same polarization direction as that of the optical unit 2 for the right eye is attached to 3. Therefore, there is a parallax of 2
The two images are completely separated and observed, enabling stereoscopic viewing.

FIG. 8 is a block diagram of a conventional rear-type projection display system for stereoscopic vision. The left-eye optical unit 1 has a polarizing plate 3 and the right-eye optical unit 2 has a polarizing plate 4 for a left-eye image. The light 5 and the right-eye image light 6 are attached so as to be incident on the incident surface of the reflection mirror 7 in polarization directions of ± 45 degrees orthogonal to each other. The image lights 5 and 6 are reflected by the reflection mirror 7 and then projected on the transmissive screen 10. The observer can separate the left and right images using stereoscopic vision by using the polarizing glasses 11 to which the polarizing plates 12 and 13 are attached so as to correspond to the polarized light of ± 45 degrees orthogonal to each other.

[0004]

The conventional front projection display system for stereoscopic vision is constructed as described above, and although it is easy to obtain a large screen, the contrast is lowered in a bright room so that it cannot be viewed. There is a problem that there is no.

Further, when the conventional projection display system for stereoscopic vision is used as a rear projection type having a reflection mirror, the following problems occur.

As shown in FIG. 9, a reflection mirror 15 is generally used.
When linearly polarized light 17 that forms an angle X16 with respect to the incident surface
s19), the component Rp21 parallel to the incident surface of the reflected light 20, the component Rs22 perpendicular to the incident surface, the angle Y formed by the incident surface, and the phase difference D are expressed by the following equations. tan (X) = As / Ap (1) Rp = rp × Ap × exp (idp) (2) Rs = rs × As × exp (ids) (3) tan (Y) = (rs / rp) × exp (-iD) × tan (X) (4) D = dp-ds (5) where rp: absolute value of reflectance of a component parallel to the incident surface rs: reflection of a component perpendicular to the incident surface Absolute value of the ratio dp: Phase change after reflection of the component parallel to the incident surface ds: Phase change after reflection of the component perpendicular to the incident surface The reflected light 20 generally has the phase difference D shown in Expression (5). Therefore, the incident linearly polarized light 17 changes to elliptically polarized light after being reflected, for example, as shown in FIG. 10, depending on the value of D.

In the conventional rear-type projection display system for stereoscopic vision, polarizing plates are arranged so that the polarization directions of two orthogonal linearly polarized lights are ± 45 degrees with respect to the ground at the observer's place. . At this time, the polarization angle 16 to the reflection mirror is ± 45 degrees. Two orthogonal linearly polarized lights having a polarization angle of ± 45 degrees are reflected by a reflecting mirror, and then change to elliptically polarized light when a slight orthogonal polarization component is generated in addition to the original linearly polarized light. After that, when the left and right images are separated by the polarized glasses, there is a polarization component corresponding to the opposite eye in the elliptically polarized light, so that the component causes crosstalk and stereoscopic vision is disturbed.

The present invention has been made to solve the above-mentioned problems, and it can be used in a bright room, and has a pair of parallax images while having a reflecting mirror in its optical path. An object of the present invention is to obtain a stereoscopic projection type display system for polarized glasses which does not cause crosstalk.

[0009]

In a stereoscopic projection display system according to claim 1 of the present invention, the polarization directions of polarizing plates which are orthogonal to each other are made to enter parallel or perpendicularly to the incident surface of a reflection mirror. It was placed in.

A projection display system for stereoscopic vision according to claim 2 of the present invention has the same structure as that of claim 1, and uses a surface mirror having a small difference in reflectance between parallel polarized light and vertical polarized light as a reflection mirror. It was what I had.

A projection display system for stereoscopic vision according to a third aspect of the present invention is the brightness of two sets of image lights orthogonal to each other on a screen surface caused by a difference in reflectance between parallel polarized light and vertical polarized light in a reflecting mirror. By adjusting the brightness of the two image sources, the brightness observed by the left and right eyes is equally compensated.

A projection display system for stereoscopic vision according to a fourth aspect of the present invention uses a back mirror as a reflection mirror,
By adjusting the brightness of two sets of image sources, the difference in brightness of two sets of image lights orthogonal to each other on the screen surface caused by the difference in reflectance between parallel polarized light and vertical polarized light on the rear-view mirror is adjusted. It is designed to compensate for the brightness observed at.

A projection display system for stereoscopic vision according to a fifth aspect of the present invention has a retardation plate disposed near the screen.

According to a sixth aspect of the present invention, a projection display system for stereoscopic vision has a retardation plate arranged at an exit of a projection lens equipped with a polarizing plate for projected images.

[0015]

In the projection display system for stereoscopic vision according to the first and second aspects of the present invention, the incident polarization planes of the two sets of image light whose polarization planes are orthogonal to each other to the reflection mirror are perpendicular to the incidence planes. Alternatively, since the two sets of image light are parallel, the two sets of image light reach the polarized glasses without the linearly polarized light being broken by the reflection by the reflecting mirror. Therefore, it is possible to prevent the crosstalk between the two sets of images.

In the projection display system for stereoscopic vision according to claim 2 of the present invention, since the surface mirror having a small difference in reflectance between the vertically polarized light and the parallel polarized light is used as the reflection mirror, the brightness of two sets of images is Difference can be reduced.

In the projection display system for stereoscopic vision according to claims 3 and 4 of the present invention, the brightness of the two image sources is compensated for the difference in reflectance between the vertically polarized light and the parallel polarized light at the reflection mirror. The brightness of the two sets of image light can be made equal because the brightness is adjusted to.

In the projection display system for stereoscopic vision according to the fourth aspect of the present invention, since the rear surface mirror with less phase difference generation is used for the reflection mirror, the crosstalk between two sets of images can be reduced.

In the projection display system for stereoscopic vision according to claim 5 of the present invention, elliptically polarized light generated by two sets of linearly polarized light whose polarization planes are orthogonal to each other is reflected by the reflecting mirror, and the elliptically polarized light is reflected behind the reflecting mirror. Since the elliptically polarized light is returned to the linearly polarized light by being compensated by the phase difference plate disposed in the above, it is possible to prevent the crosstalk between the two sets of images.

In the projection display system for stereoscopic vision according to claim 6 of the present invention, the projection image polarization plate is arranged so that the two sets of image light are reflected by the reflection mirrors and then changed into linearly polarized lights orthogonal to each other. Since the retardation film is selected and arranged on the front surface of the reflection mirror further behind, it is possible to prevent the occurrence of crosstalk between two sets of images.

[0021]

【Example】

Example 1. FIG. 1 is a block diagram of a stereoscopic projection display system according to claim 1 of the present invention. In the figure,
1 is a left-eye image projection optical unit, 2 is a right-eye image projection optical unit, 3 is a left-eye image polarization plate, 4 is a left-eye image polarization plate, 5 is a left-eye image light, 6 is a right-eye image light, and 7 is Reflecting mirror, 8 reflected light of image light for left eye, 9 reflected light of image light for right eye, 10 transmissive screen, 11 polarized glasses, 12 polarized glasses for left eye image observation, 13 polarized light for right eye image observation They are glasses.

The left-eye image projection optical unit 1 is provided with a polarizing plate 3 so that the plane of polarization is perpendicular to the plane of incidence of the reflection mirror 7, and the right-eye image projection optical unit 2 is provided with a plane of polarization parallel to it. A polarizing plate 4 is arranged on the. Since the left-eye image light 5 is incident in the polarization direction perpendicular to the incident surface of 7, even if the reflection mirror produces the phase difference D represented by the formula (5) with respect to the vertical polarization and the parallel polarization. Its reflected light 8
The polarization state of does not change. Similarly, the right-eye image light 6 is incident in the polarization direction parallel to the incident surface of 7, so that the polarization state of the reflected light 9 does not change. As a result, 8 and 9 reach the transmissive screen 10 while preserving the linearly polarized light and maintaining the polarization angles orthogonal to each other. The observer views the images with parallax of 8 and 9 on the polarizing plates 12 and 13 attached to the glasses 11.
Although it is separated and observed at, the stereoscopic image can be recognized by the image without crosstalk. By using such a combination of polarization directions, good stereoscopic vision can be realized even if an arbitrary mirror that generates a large phase difference is used.

Example 2. Usually, the reflection mirror has different reflectances for parallel polarized light and vertical polarized light. In the stereoscopic projection display system according to the first embodiment, the mutually orthogonal linearly polarized lights are incident on the reflection mirror in parallel and perpendicular planes of polarization, so that crosstalk between two sets of image light is suppressed. However, there may be a problem that the brightness balance of the two sets of image light is lost. The projection display system for stereoscopic vision according to claim 2 of the present invention has the same configuration as that of the above-described first embodiment, and uses a surface mirror having a small reflectance difference between parallel polarized light and vertical polarized light as the reflection mirror 7 in FIG. As shown in FIG. 2, for example, a surface mirror in which aluminum 24 is vapor-deposited on a glass substrate 23 and further overcoated with a polymer material 25 has a phase difference between parallel polarized light and vertical polarized light. Since the difference in reflectance is small, the difference in brightness between the reflected light 8 of the left-eye image light and the reflected light 9 of the right-eye image light is small, and a stereoscopic image in which the difference in brightness between the left and right images is small can be realized.

Example 3. FIG. 3 is a configuration diagram of a stereoscopic projection display system according to claim 3 of the present invention.
Generally, except for the surface mirror of the second embodiment, since the difference in reflectance between the parallel polarized light and the vertical polarized light with respect to the incident surface is large, the polarization angles of the two sets of orthogonal image lights 5 and 6 are other than ± 45 degrees. When, the balance of the brightness of the reflected light 8 and 9 is lost. Therefore, in FIG. 3, when the polarization direction of the image light 5 for the left eye is perpendicular to the incident surface of the reflection mirror and the polarization direction of the image light 6 for the right eye is parallel, the reflectance of the vertically polarized light is rs, and the reflection of the parallel polarized light is If the ratio is rp, if the left eye image source and the right eye image source are adjusted in advance so that the brightness of the image light 5 becomes (rp / rs) times the brightness of the image light 6, The reflected light 8 of the image light and the reflected light 9 of the image light for the right eye have almost the same brightness, and a stereoscopic image in which the brightness of the left and right images is equal can be realized.

In this embodiment, the polarization directions of the two sets of the orthogonal image lights 5 and 6 are not limited to the vertical and parallel directions, but may be other angles. Even in that case, the brightness of the two sets of image sources may be adjusted so that the brightness of the two sets of reflected image light 8 and 9 becomes equal. The brightness can be adjusted by adjusting the amount of drive current when the image source is a CRT, or by adjusting the brightness of the backlight when using a liquid crystal panel. The amount of emitted light may be adjusted with an ND filter or the like.

Example 4. FIG. 4 is a configuration diagram of a rear surface mirror in a stereoscopic projection display system according to claim 4 of the present invention. The back surface mirror (FIG. 4) that reflects light on the back surface of the mirror has a large difference in reflectance between parallel polarized light and vertical polarized light, but a small phase difference is generated. Therefore, even if the polarization direction of the incident image light is not parallel or perpendicular, a stereoscopic image with less crosstalk can be realized. The left and right brightness unbalance caused by the reflectance difference may be adjusted by the same method as in the third embodiment.

Example 5. FIG. 5 is a block diagram of a stereoscopic projection display system according to claim 5 of the present invention.
A retardation plate 26 is arranged on the front surface of the screen 10.
The retardation plate 26 is selected so as to compensate for the retardation D represented by the equation (5). The reflected lights 8 and 9 of the left-eye and right-eye image lights 5 and 6, which are set to be linearly polarized light orthogonal to each other, are changed to elliptically polarized light by reflection. However, by passing through the phase difference plate 26 installed on the front surface of the screen, the linearly polarized lights which are mutually orthogonal are returned. The observer can separate the left and right images without crosstalk by the polarizing glasses 11 having the polarizing plates 12 and 13 attached in the directions corresponding to the left and right image lights.

In this embodiment, the position of the retardation plate 26 is on the observer side of the reflection mirror and the polarizing plate 1 for image observation is used.
It may be before 2 and 13. For example, the polarizing glasses 11 may be attached in front of the polarizing plates 12 and 13.

Example 6. FIG. 6 is a block diagram of a stereoscopic projection display system according to claim 6 of the present invention.
A retardation plate 27 for the left eye is arranged behind the polarizing plate 3 for the left eye, and a retardation plate 28 for the right eye is arranged behind the polarizing plate 4 for the right eye. The left-eye image light 5 and the right-eye image light 6 are elliptically polarized by the phase difference plates 27 and 28 and are reflected by the reflection mirror 7. However, since the phase difference plates 27 and 28 are selected and arranged so that the image lights 5 and 6 are subjected to the phase difference generating action by the reflection mirror and are changed into the linearly polarized lights which are orthogonal to each other after being reflected, the screen 10 has a 2 phase difference. A set of orthogonal linearly polarized light arrives. The observer uses the polarizing plate 1 in the direction corresponding to the left and right image lights.
The polarized glasses 11 to which 2 and 13 are attached can separate left and right images without crosstalk.

In this embodiment, the phase difference plate 27,
The position of 28 may be anywhere behind the polarizing plates 3 and 4 and before the reflection mirror 7.

[0031]

As described above, according to the projection display system for stereoscopic vision according to the first and second aspects of the present invention, the polarization directions of two sets of image lights which are orthogonal to each other are perpendicular or parallel to the reflection mirror. Since the light is set to be incident on, the linearly polarized light is preserved even after being reflected by the mirror. Therefore, two sets of images can be separated with polarized glasses without crosstalk,
It can realize clear 3D images.

According to the projection display system for stereoscopic vision according to claim 2 of the present invention, since the surface mirror is used as the reflecting mirror, the difference in reflectance between the vertically polarized light and the parallel polarized light in the reflecting mirror is small, and two sets are provided. It is possible to realize a stereoscopic image with a small difference in brightness of the image.

According to the projection display system for stereoscopic vision according to claims 3 and 4 of the present invention, the brightness of the two sets of image light sources is adjusted so that the two sets of image lights have almost the same brightness after being reflected by the mirrors. Since the setting is made, it is possible to realize a stereoscopic image in which the difference in brightness between the two sets of images is small.

According to the projection display system for stereoscopic vision according to the fourth aspect of the present invention, since two rear surface mirrors are used, which generate a small phase difference between the parallel polarized light and the vertical polarized light at the time of reflection, two sets of orthogonal mirrors are used. Even if the polarization plane of the image light is not parallel or vertical, a stereoscopic image with less crosstalk can be realized.

According to the projection display system for stereoscopic vision according to the fifth aspect of the present invention, the elliptically polarized light generated after the reflection by the mirror is returned to the linearly polarized light by the phase difference plate installed between the rear surface of the reflecting mirror and the screen surface. Therefore, regardless of the polarization directions of the two sets of orthogonal image light, the two sets of images can be separated by the polarized glasses without crosstalk, and a clear stereoscopic image can be realized.

According to the projection display system for stereoscopic vision according to the sixth aspect of the present invention, the two sets of the orthogonal image lights are subjected to the phase difference generating action by the reflection mirror, and after being reflected, are changed into the linearly polarized lights which are orthogonal to each other. Since the retardation plate is placed in front of the reflection mirror, regardless of the polarization directions of the two sets of orthogonal image light, the two pairs of images can be separated with polarizing glasses without crosstalk, and a clear stereoscopic image is realized. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a stereoscopic projection display system according to claims 1 and 2 of the present invention.

FIG. 2 is a diagram illustrating a configuration of a front surface mirror according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a stereoscopic projection display system according to claim 3 of the present invention.

FIG. 4 is a configuration diagram of a rear surface mirror in the stereoscopic projection display system according to claim 4 of the present invention.

FIG. 5 is a configuration diagram of a stereoscopic projection display system according to claim 5 of the present invention.

FIG. 6 is a configuration diagram of a stereoscopic projection display system according to claim 6 of the present invention.

FIG. 7 is a configuration diagram of a conventional front-type stereoscopic projection display system.

FIG. 8 is a configuration diagram of a conventional rear-type stereoscopic projection display system.

FIG. 9 is a diagram illustrating a change in polarization state due to reflection.

FIG. 10 is a diagram illustrating a change from linearly polarized light to elliptically polarized light due to reflection.

[Explanation of symbols]

 1 Left-eye image projection optical unit 2 Right-eye image projection optical unit 3 Left-eye image polarizing plate 4 Right-eye image polarizing plate 5 Left-eye image light 6 Right-eye image light 7 Reflection mirror 8 Left-eye image reflection light 9 Right-eye image reflection Light 10 Transmissive screen 11 Polarizing glasses 12 Polarizing plate for left eye image observation 13 Polarizing plate for right eye image observation

Claims (6)

[Claims] 1. An image source, at least two sets of optical units having an optical system for magnifying and projecting an image, and at least one reflection mirror, each optical unit enabling stereoscopic viewing. In a stereoscopic projection display system that projects different images with polarized light fluxes orthogonal to each other, projects them on a transmissive screen through reflection by a reflection mirror, and recognizes stereoscopic images with polarizing glasses whose polarization directions are orthogonal to each other, A projection display system for stereoscopic viewing, characterized in that the polarization directions of polarizing plates orthogonal to each other are arranged so as to enter parallel or perpendicular to the entrance surface of a reflecting mirror. 2. The projection display system for stereoscopic vision according to claim 1, wherein a surface mirror that reflects light in the vicinity of the mirror surface is used as the reflection mirror. 3. An image source, at least two sets of optical units having an optical system for magnifying and projecting an image, and at least one reflection mirror, each optical unit enabling stereoscopic vision. In a stereoscopic projection display system that projects different images with polarized light fluxes orthogonal to each other, projects them on a transmissive screen through reflection by a reflection mirror, and recognizes stereoscopic images with polarizing glasses whose polarization directions are orthogonal to each other, A solid body having means for adjusting the brightness of two sets of image sources so as to compensate for the difference in brightness of the two sets of image light caused by the difference in reflectance between parallel polarized light and vertical polarized light in the reflecting mirror. Visual projection display system. 4. The projection display system for stereoscopic vision according to claim 3, wherein a rear surface mirror that reflects light in the vicinity of the rear surface of the mirror is used as the reflection mirror. 5. An optical source and an optical system for enlarging and projecting an image, at least two sets of optical units, and at least one reflection mirror, each optical unit being different for enabling stereoscopic vision. In a projection display system for stereoscopic vision, an image is projected as polarized light fluxes orthogonal to each other, projected on a transmissive screen through reflection by a reflection mirror, and a stereoscopic projection display system for recognizing stereoscopic images with polarizing glasses whose polarization directions are orthogonal to each other. A projection display system for stereoscopic vision, which is characterized in that a retardation plate is arranged in the vicinity. 6. An image source and at least two optical units having an optical system for magnifying and projecting an image, and at least one reflecting mirror, each optical unit being different for enabling stereoscopic vision. Projection in a stereoscopic projection display system in which an image is projected as polarized light beams orthogonal to each other, projected on a transmissive screen through reflection by a reflection mirror, and stereoscopic images are recognized by polarizing glasses whose polarization directions are orthogonal to each other. A projection display system for stereoscopic vision, which is characterized in that a phase difference plate is arranged at a lens exit.