JPH0954375A - Liquid crystal projection device for stereoscopic vision - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stereoscopic video display by using a pair of liquid crystal projectors in the same specification. SOLUTION: The videos for a left eye and a right eye subjected to image pickup with binocular parallax are projected with the same polarized light from a pair of left and right liquid crystal projectors 12L and 12R, and either projected video is reflected by a reflecting mirror 13 to switch a polarization direction, and superposed on the other projected video and projected on the screen 14, so that stereoscopic vision is realized by polarizing spectacles 15 whose polarization direction is different between the left eye and the right eye. By combining two projectors 12L and 12R which are far compacter than a color projection tube with reflecting mirror 13, the liquid crystal projection device for stereoscopic vision is provided at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic liquid crystal projection apparatus that enables stereoscopic viewing of images projected by a pair of liquid crystal projectors with polarizing glasses having different left and right polarization directions.

[0002]

2. Description of the Related Art A three-dimensional display device for displaying a stereoscopic image is a stereoscopic image system in which image information for the two left and right eyes is independently applied to both eyes to express the depth, and an arbitrary viewpoint within a limited range. Can be divided into a three-dimensional image method that expresses the depth by allowing observation. The stereoscopic image system is also called a twin-lens system, and the stereoscopic projection tube device 1 shown in FIG. 5 has a polarization direction on the front surfaces of two color projection tubes 2L and 2R prepared for the left eye and the right eye. A pair of linearly polarizing plates 3L and 3R orthogonal to each other are provided, and left and right video signals imaged with binocular parallax are projected from the color projection tubes 2L and 2R onto the screen 5 via the half mirror 4. The left-eye image projected from the left-eye color projection tube 2L is directly transmitted through the half mirror 4 and projected onto the screen 5, and the right-eye image projected from the right-eye color projection tube 2R is The optical path is deflected at a right angle by the half mirror 4 and projected on the screen 5. The image projected on the screen 5 can be viewed stereoscopically with binocular parallax by wearing the polarizing glasses 6 made of linear polarizing plates whose polarization directions are orthogonal to each other for the left eye and the right eye. .

In general, the projected images of the color projection tubes 2L and 2R are light waves that are not polarized in a specific direction and vibrate in any direction within a plane perpendicular to the traveling direction of light. Therefore, as it is, it cannot be separated right and left by the polarizing glasses 6, and it is necessary to make the polarization directions different by the polarizing plates 3L and 3R whose polarization directions are orthogonal to each other. Therefore, in the case of this example, the linear polarization plate 3L is provided with the linear polarization plate 3L so that vertical polarization and horizontal polarization whose polarization directions do not change due to transmission or reflection of the half mirror 4 can be obtained.
A vertical polarizing plate that outputs polarized light whose vibration direction is perpendicular to the optical axis, and a horizontal polarizing plate whose vibration direction is horizontal to the optical axis are used for the linear polarizing plate 3R. As a result, the left-eye image transmitted through the half mirror 4 is projected as vertical polarization, and the right-eye image reflected by the half mirror 4 is projected as horizontal polarization on the screen 5 for stereoscopic viewing through the polarizing glasses 6. To be done.

[0004]

In the conventional stereoscopic projection tube apparatus 1 described above, the image projected by the color projection tubes 2L and 2R is provided on the front surface of the projection lens, and a pair of polarizing plates 3L whose polarization directions are orthogonal to each other. , 3R to guide to the half mirror 4, the left-eye image and the right-eye image are superimposed on the same optical axis and projected on the screen 5, and a pair of polarizing plates 3L having polarization directions orthogonal to each other. The 3R and the half mirror 4 are indispensable optical components. However, half mirror 4
Is expensive, and the incident optical axis of the color projection tube 2L for the left eye on the half mirror 4 and the incident optical axis of the color projection tube 2R for the right eye on the half mirror 4 are orthogonal to each other, and the emission optical axis is The optical axis adjustment for aligning and projecting vertically on the screen 5 is also complicated, and the three-tube type color projection tubes 2L, 2
Since the R is not only heavy but also large in size, it has problems such as being difficult to introduce to general households, except for households blessed with a place where a large viewing space can be secured.

On the other hand, a liquid crystal projector which is superior to the color projection tubes 2L and 2R in terms of space saving is used.
Attempts have also been made to arrange the stands side by side and adjust the projection directions so that the respective projection centers coincide with the center point of the screen so that stereoscopic images can be viewed by wearing polarized glasses. However, the image projected from the liquid crystal projector is
Originally, polarized light is applied in a specific direction, so it is not possible to add a polarizing plate in front of the projection lens to arbitrarily change the polarization direction of the projected image. It has to be composed of two types of projectors whose polarization directions are orthogonal to each other, such as a projection type or a horizontal polarization projection type. In other words, it is necessary to make different the configuration of the optical system inside the liquid crystal projector for the left eye and the right eye, and the device configuration is complicated compared to the case where two liquid crystal projectors with the same polarization direction are aligned, and the manufacturing cost is low. There were issues such as high cost.

The present invention changes the polarization direction by reflecting one projection image of a pair of left and right liquid crystal projectors that are polarized in the same direction in the same direction by a reflecting mirror.
By combining with the other projected image on the screen,
An object of the present invention is to enable stereoscopic viewing by separately viewing left and right images captured with binocular parallax through polarizing glasses having different left and right polarization directions.

[0007]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems, and a left-eye image and a right-eye image captured with binocular parallax are polarized with the same polarization direction when reflected. A pair of left and right liquid crystal projectors, a reflecting mirror that reflects one projection image of the pair of liquid crystal projectors, and switches the polarization direction at that time, a projection image reflected by the reflecting mirror, and the pair of liquid crystal projectors. A screen for projecting and synthesizing the other projected image of
Polarization glasses for the left eye and the right eye have different polarization directions, and the left eye and the right eye are stereoscopically viewed on the screen, and polarizing glasses are provided.

According to the present invention, the pair of liquid crystal projectors are 45 ° linear polarization projection type liquid crystal projectors that project a linearly polarized image having a polarization direction of 45 ° with respect to a horizontal or vertical polarization direction. Alternatively, it is a linear polarization projection type liquid crystal projector for projecting a linearly polarized image, and is characterized in that it is provided with a quarter wavelength plate for converting linearly polarized light into circularly polarized light on the front surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram showing an embodiment of a stereoscopic liquid crystal projection device of the present invention, FIG. 2 is a diagram for explaining the relationship between the reflecting mirror shown in FIG. 1 and linearly polarized light, and FIG. It is explanatory drawing which shows that 45 degree linearly polarized light bends 90 degrees with a reflecting mirror.

The stereoscopic liquid crystal projection device 11 shown in FIG.
A left-eye video signal and a right-eye video signal having the same polarization direction are projected from the pair of liquid crystal projectors 12L and 12R, and one projection image is reflected by the reflecting mirror 13 to switch the polarization direction,
The projected image reflected by the reflecting mirror 13 and the other projected image are combined on the screen 14, and the left and right images are separated and visually recognized by the polarizing glasses 15 having different polarization directions for the left eye and the right eye, thereby providing a stereoscopic view. It is configured to do.

The liquid crystal projector 12 for the left eye shown in the embodiment
Both L and the liquid crystal projector 12R for the right eye have a polarization direction of 45 ° with respect to the optical axis along the projection direction.
It projects a linearly polarized image, and since the models are the same, their polarization directions are completely the same. Further, in the embodiment, the liquid crystal projector 12L for the left eye is connected to the screen 1
4, the liquid crystal projector 12R for the right eye is arranged so that the mirror image by the reflecting mirror 13 (shown by the one-dot chain line in FIG. 1) almost directly faces the screen 14. However, the mirror images of the liquid crystal projector 12L for the left eye and the liquid crystal projector 12R for the right eye by the reflecting mirror 13 are arranged side by side with a predetermined distance from each other so as to form a common angle of view on the screen 14. Center of the projection optical axis of the screen 14
It is adjusted to match at the center point of.

The arrangement of the liquid crystal projector 12R for the right eye is such that the mirror image of the liquid crystal projector 12R for the right eye is upside down with respect to the liquid crystal projector 12L for the left eye.
Although it is fixed appropriately, this is fixed to both the left and right sides by the liquid crystal projectors 12L and 12R which are optically designed so that the projection center line is incident on the screen 14 with a driving angle θ of 5 to 10 ° without causing vertical trapezoidal distortion. This is because, when the same video signal is input, the image shift due to the upper and lower trapezoidal distortion does not occur, and the optimum arrangement is for matching the two video images for the left eye and the right eye on the screen 14. .

The left-eye video signal and the right-eye video signal are assumed to be imaged with binocular parallax, and here, as the left-eye video signal source 16L or the right-eye video signal source 16R, A video signal transmitting device such as a video tape recorder (VTR) or a laser disk player (LDP), a high-definition signal transmitting device or a video signal transmitting device of computer graphics is used. Further, in order to synchronize the left and right projected images, a sync signal generator 17 is commonly connected to the left and right video signal sources 16L and 16R, and the video signal source is generated based on the sync signal generated by the sync signal generator 17. 16L and 16R are driven synchronously.

As is well known, there are two types of polarized light, linearly polarized light and circularly polarized light. When linearly polarized light is reflected by the reflecting mirror 13, longitudinally polarized light and horizontally polarized light are polarized in the polarization direction. No change is seen, but it is also known that the 90 ° polarization direction changes for oblique 45 ° polarization. Therefore, the oblique 45 ° polarized light projected from the right-eye liquid crystal projector 12R and incident on the reflecting mirror 13 is changed to the reverse oblique 45 ° polarized light by reflection. More specifically, for example, as shown in FIG. 2, a normal line t is set at the point of incidence of linearly polarized light on the reflecting mirror 13, and a plane including the normal line t is the reflecting mirror 13.
Let y be the line that intersects with the reflection surface of, and the reflection surface 1 orthogonal to the line y
If the straight line in 3 is x, then t and x, and x and t and y
Are orthogonal to each other, but generally, a wave vibrating in a plane containing ,, t, y is called a p-wave, and a wave vibrating in a plane containing ,, x is called an s-wave. However, as shown in FIG. 3, the light entering the reflecting mirror 13 while vibrating in the directions of 45 ° in x and y, which is neither p-wave nor s-wave, is bent by 90 ° in the vibration direction. Become.

That is, as in the embodiment, the projection image for the left eye which is not reflected by the reflecting mirror 13 is linearly polarized at 45 °, whereas the projection image for the right eye which is reflected by the reflecting mirror 13 is at an oblique angle of 45 °. It becomes linearly polarized light, and the left-eye image and the right-eye image projected on the screen 14 have polarization directions orthogonal to each other. Moreover, since the polarized glasses 15 for stereoscopic vision are constructed by assembling the right-eye and left-eye polarized linear polarizers having polarization directions of 45 °, which are orthogonal to each other, the right and left projected on the screen 14. The projected image can be clearly separated and viewed as a left-eye image and a right-eye image by the polarized glasses 15.

As described above, the stereoscopic liquid crystal projection device 1 is used.
According to the first aspect, it is sufficient to prepare two liquid crystal projectors 12L and 12R having the same specifications for projecting images having the same polarization direction, and the liquid crystal projectors 12L and 12R which are much more compact than the color projection tube can be used for one liquid crystal projector. The mirror image of the reflection mirror 13 of 12R and the liquid crystal projector 12L of the other side may be installed in a state that they have the same driving angle θ with respect to the screen 14, and the reflection mirror 13 can kick the projection image of the other liquid crystal projector 12L. Since it is sufficient to dispose the device so that it is not used for household use, the device can be widely used in general households because the device is prevented from having an excessive size and weight. In addition, in a home where one liquid crystal projector 12L has already been purchased, it is possible to build a stereoscopic image system by purchasing a set of the same type of liquid crystal projector 12R and the reflecting mirror 13, and by the reflection by the reflecting mirror 13. Regarding the amount of light that attenuates,
For example, since the light amount adjustment button attached to the liquid crystal projector 12R can be used for adjustment, the left and right images can be displayed on the screen 14 with the same brightness.
Can be projected on.

In the above embodiment, a pair of liquid crystal projectors 12L, 1L that output a projection image of 45 ° linearly polarized light.
2R is used as an example, the left-eye liquid crystal projector 12L and the right-eye liquid crystal projector 12R are both circular-deflection projection types that project images having circularly polarized light that rotates in the same direction. You can also In this case, for example, the left-eye liquid crystal projector 12L is directly connected to the screen 14
When the projection image of the liquid crystal projector 12R for the right eye is reflected once by the reflecting mirror 13 and projected on the screen 14, the circularly polarized light is reflected by the reflecting mirror 13 as shown in FIG. The circularly polarized left-eye image that is directly projected and the reflecting mirror 1 have the property that the turning direction is the reverse turning.
The image for the right eye, which is reflected by 3 and turned in the opposite direction, can be viewed separately through the polarizing glasses incorporating the corresponding circularly polarizing plate. That is, stereoscopic viewing is possible as in the case of using a 45 ° linear polarization projection type liquid crystal projector.

Further, the liquid crystal projectors 12L and 12R of the linear polarization projection type can be used as they are without using the circular polarization projection type, and stereoscopic viewing by the circular polarization type deflection glasses can be made possible. That is, as shown in the stereoscopic liquid crystal projector 21 shown in FIG. 5, linearly polarized light is generated by arranging the quarter-wave plate 22 at an angle of 45 ° with the polarization axis in front of the projection lens. It can be changed to circularly polarized light. In this case, the projected images of the liquid crystal projectors 12L and 12R can be converted into circularly polarized light by using the quarter-wave plate 22, but since the polarization direction of one projected image is reversed by the reflecting mirror 13, stereoscopic viewing is possible. Become. Liquid crystal projection device 21 for stereoscopic viewing
Can use a pair of linearly polarized light projection type liquid crystal projectors 12L and 12R having the same polarization direction, and the left and right quarter-wave plates 22 that switch the linearly polarized light to circularly polarized light can also use the same standard. Therefore, it can be manufactured at low cost without increasing the types of parts used.

In each of the above embodiments, the projection image of the right-eye liquid crystal projector 12R is reflected by the reflecting mirror 13. However, the projection image of the left-eye liquid crystal projector 12L is reflected by the reflecting mirror, and the right image is projected. LCD projector for eye 12R
It is also possible to have a configuration in which the projection image of is directly projected on the screen 14.

[0020]

As described above, according to the present invention,
The left-eye image and the right-eye image captured with binocular parallax are projected from the pair of left and right liquid crystal projectors with the same polarization, and one projection image is reflected by the reflecting mirror to switch the polarization direction, and the other Since it is configured so that the left eye and the right eye can stereoscopically view with polarizing glasses having different polarization directions by projecting on the screen on the projected image, the liquid crystal projector of the same specification that projects the image having the same polarization direction is used.
It is sufficient to prepare a stand, and a liquid crystal projector that is much more compact than a color projection tube is installed with the mirror image by the reflecting mirror of one liquid crystal projector and the other liquid crystal projector having the same driving angle with respect to the screen. It is sufficient to dispose the reflector so that it does not block the projected image of the other liquid crystal projector, and it is released from the excessive size and weight of the device that hinders its widespread use in homes. In addition, in a home where one LCD projector has already been purchased, it is possible to build a stereoscopic image system by purchasing a set of LCD projector and reflector, and it is attenuated by reflection by the reflector. The light intensity can also be adjusted with the light intensity adjustment button attached to the LCD projector, so the left and right images are displayed on the screen with the same brightness. An excellent effect such as can be projected.

Further, according to the present invention, the pair of liquid crystal projectors are 45 ° linear polarization projection type liquid crystal projectors which project a linearly polarized image having a polarization direction of 45 ° with respect to the horizontal or vertical polarization direction. Unlike polarized light or horizontal polarized light that does not change in the polarization direction when reflected by a reflecting mirror, the polarization direction changes by 90 ° when the projection image of obliquely 45 ° polarized light is reflected by the reflecting mirror, and reverse oblique 45 °. Since it switches to polarized light, by using this property and wearing polarized glasses having different left and right polarization directions, the left and right images captured with binocular parallax can be stereoscopically viewed.

Further, according to the present invention, the pair of liquid crystal projectors is a linear polarization projection type liquid crystal projector for projecting a linearly polarized image, and is provided with a quarter wavelength plate for converting linearly polarized light into circularly polarized light on the front surface. Therefore, by changing the linearly polarized light into circularly polarized light by arranging a quarter wave plate at the front of the two liquid crystal projectors that project an image of linearly polarized light at an angle of 45 ° with the polarization axis. , One of the projected images can be stereoscopically viewed by rotating the polarization direction in reverse with a reflecting mirror, and the same model of liquid crystal projector, that is, the same linearly polarized image can be projected, and the linearly polarized light is switched to circularly polarized light. As for the quarter-wave plate, the same standard can be used on the left and right sides.
There is an effect that it can be manufactured at low cost without increasing the types of parts used.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a stereoscopic liquid crystal projection device of the present invention.

FIG. 2 is a diagram for explaining the relationship between the reflecting mirror shown in FIG. 1 and linearly polarized light.

FIG. 3 is an explanatory diagram showing that 45 ° linearly polarized light is bent 90 ° by a reflecting mirror.

FIG. 4 is an explanatory diagram showing that circularly polarized light is reversely rotated by a reflecting mirror.

FIG. 5 is a schematic configuration diagram showing another embodiment of the stereoscopic liquid crystal projection device of the present invention.

FIG. 6 is a schematic configuration diagram showing an example of a conventional stereoscopic projection tube device.

[Explanation of symbols]

 11, 21 Stereoscopic liquid crystal projection device 12L, 12R Liquid crystal projector 13 Reflector 14 Screen 15 Polarizing glasses 16L, 16R Video signal source 17 Synchronization signal generator 22 Quarter wave plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 13/04 H04N 13/04

Claims (3)

[Claims] 1. A pair of left and right liquid crystal projectors that project a left-eye image and a right-eye image captured with binocular parallax with the same polarized light whose polarization direction changes upon reflection, and one of the pair of liquid crystal projectors. A reflection mirror for reflecting the projection image of the above and switching the polarization direction at that time, a screen for projecting and combining the projection image reflected by the reflection mirror and the other projection image of the pair of liquid crystal projectors, and a left eye 2. The stereoscopic liquid crystal projection device according to claim 1, further comprising polarizing glasses for stereoscopically viewing left-eye and right-eye images projected on the screen with different polarization directions for the right eye. 2. The three-dimensional liquid crystal projector is a 45 ° linear polarization projection type liquid crystal projector that projects a linearly polarized image having a polarization direction of 45 ° with respect to a horizontal or vertical polarization direction. Liquid crystal projection device for vision. 3. The pair of liquid crystal projectors are linearly polarized light projection type liquid crystal projectors that project an image of linearly polarized light, and are provided with a quarter wavelength plate for converting linearly polarized light into circularly polarized light on the front surface. The liquid crystal projection device for stereoscopic vision according to claim 1.