JPH0926555A - Stereoscopic image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stereoscopic image display device having well balanced luminance. SOLUTION: In a stereoscopic image display device provided with an image projection part, a screen on which an image from the image projection part is formed and an optical means arranged on the observer's side of the screen and mutually separating left and right images, the image projection part is provided with a liquid crystal unit 12 forming a left-eye image, a liquid crystal unit 11 forming a right-eye image, a polarizing beam splitter 4 for splitting light from a light source 1 into projecting light for left eye and projecting light for right eye and a relay lens 15 arranged on the side of a longer optical path of optical paths introducing the projecting light beams separated by the polarizing beam splitter 4 to the liquid crystal units for left eye and right eye 11, 12, the projecting light beams separated by the polarizing beam splitter 4 are made incident on the liquid crystal units for left eye and right eye 11, 12 with the same light quantity and projected on the screen by means of projection lenses 13, 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic image display device, and more particularly, to a projection type stereoscopic image display device that allows stereoscopic images to be observed without glasses.

[Prior art]

As a projection type stereoscopic image display device without glasses which has been conventionally known, there is a double lenticular type projection stereoscopic image display device in which lenticular plates are arranged on both sides of a diffusion plate which constitutes a screen. FIG. 2 shows the configuration of a projection type stereoscopic image display device using this double lenticular method.

The apparatus shown in FIG. 2 comprises a liquid crystal projector 20L dedicated to the left-eye image and a liquid crystal projector 2 dedicated to the right-eye image.
With 0R. The two liquid crystal projectors 20L and 20R are arranged at positions where the distance between the optical axes of the two liquid crystal projectors is 65 × (2n + 1) mm (n is an integer). The respective images projected from the liquid crystal projectors 20L and 20R are incident on the lenticular plate 30 arranged on the projector side, and then converged by the lenticular plate 30 to be alternately left and right on the diffusion plate 31 with the black portion interposed therebetween. The images L and R of the image are formed in stripes. Then, the left and right images are separated by the lenticular 32 plate provided on the observer side of the diffusion plate 31, the right eye image R is observed by the observer's right eye, and the left eye image L is observed by the left eye, It enables stereoscopic viewing.

In the above-mentioned conventional apparatus, since two liquid crystal projectors are used, two lamps, two reflectors and two lamp power sources as expensive light sources are required, which causes a problem of high cost.

Therefore, a device capable of displaying a stereoscopic image with one light source has been proposed (see Japanese Patent Application No. 6-207025). A configuration example of this device is shown in FIG.

As shown in FIG. 3, this device uses a polarization beam splitter 4 as an optical means for separating the light source light into a left-eye projection light and a right-eye projection light in the image projection unit,
The light from one light source unit 1 is split into left-eye projection light and right-eye projection light for use. That is, the polarization beam splitter 4 polarizes and separates the light source light by reflecting S-polarized light and transmitting P-polarized light of the incident light source light from the light source unit 1.

As shown in FIG. 3, in the image projection unit, the light emitted from the light source unit 1 including the lamp 2 and the reflector 3 is given to the polarization beam splitter 4.
With this polarization beam splitter 4, as described above,
Light source light from the light source unit 1 is polarized and separated into left eye projection light and right eye projection light.

Then, the reflected S-polarized light is rotated 90 degrees by the retardation film 5 and is polarized into P-polarized light, and then, for example, the liquid crystal unit 1 for forming an image for the right eye.
Given to one. Further, the transmitted P-polarized light is reflected by the reflection mirror 6 and given to, for example, the liquid crystal unit 12 that forms an image for the left eye. This liquid crystal unit 11, 1
Reference numeral 2 is a liquid crystal panel 11b, 12b, an incident side polarization plate 11
a, 12a, emission side polarization plates 11c, 12c and the like.

Liquid crystal units 11 and 12 for the right and left eyes
The lights respectively incident on the light pass through the images formed on the liquid crystal panels 11b and 12b of the liquid crystal units 11 and 12, become image lights, and are projected on the screen portion (not shown) via the projection lenses 13 and 14. It These projection lenses 13 and 14 are arranged at positions where the distance between the optical axes of the projection lenses 13 and 14 is 65 × (2n + 1) mm (n is an integer), as in the case shown in FIG.

Although not shown, the screen portion of this device has a lenticular plate on the image projection side of the diffuser plate for the right eye, similar to that shown in FIG. A configuration is used in which the images for the left eye are respectively converged, and further, a lenticular plate for separating left and right images is provided on the viewer side of the diffusion plate.

As described above, the images projected from the projection lenses 13 and 14 are separated into the left-eye image and the right-eye image, and the right-eye image R of the observer's right eye is the left-eye image. Then, the image L for the left eye is observed, and stereoscopic vision can be performed.

[0012]

It is generally known that the amount of light is inversely proportional to the square of the distance. In the device shown in FIG. 3, the projection lens 14 is 65 × (2n + 1) mm away from the projection lens 13. Since the light source light separated by the polarization beam splitter 4 is guided, the respective optical path lengths (distances) are different and the amounts of light incident on the projection lenses 13 and 14 are also different. That is, the S-polarized light reflected by the polarization beam splitter 4 is transmitted through the polarization beam splitter 4 as compared with the distance (optical path length) until the S-polarized light is converted into P-polarized light by the retardation film 5 and enters the liquid crystal panel 11b. There is a problem that the P-polarized light is once reflected by the reflection mirror 6 and the distance (optical path length) until it enters the liquid crystal panel 12b becomes long, the amount of light decreases, and the left and right images are unbalanced.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a stereoscopic image device having a good luminance balance.

[0014]

SUMMARY OF THE INVENTION According to the present invention, an image projecting section, a screen section on which an image from the image projecting section is formed, and left and right images arranged on the observer side of the screen section are separated. In the stereoscopic image display device, the image projection unit includes a liquid crystal panel for forming an image for the left eye, a liquid crystal panel for forming an image for the right eye, and a light source for projecting light for the left eye. And a polarization beam splitter for splitting into the projection light for the right eye, and a relay lens arranged on the side of a long optical path for guiding the projection light split by the polarization beam splitter to the liquid crystal panel for the right eye and the liquid crystal panel for the left eye, respectively. ,
The projection light separated by the polarization beam splitter is incident on the right-eye liquid crystal panel and the left-eye liquid crystal panel with the same light amount, and is projected on the screen portion by the projection lens.

Further, the relay lens is composed of three lenses, and each lens may be coated with an antireflection coating.

As described above, the system which has a long optical path until it is separated by the polarization beam splitter and reaches the liquid crystal panel, for example, the system in which the P-polarized light transmitted through the polarization beam splitter enters the liquid crystal panel, is emitted from the polarization beam splitter. Focal length (f ・ ・ ・ f / 2 ・
..Incorporate a relay lens consisting of f).

In this relay lens, the incident light is relayed, and the principal ray does not deviate from the lens system. Therefore, the ray is transmitted without being repelled, is emitted from the polarization beam splitter, and is transmitted to the first lens. You can keep the amount of light entering.

Therefore, in a system having a long optical path, for example, a system in which P-polarized light transmitted through a polarization beam splitter enters a liquid crystal panel, a relay lens having a focal length (f ... f / 2 ... f) is provided. By incorporating it, the amount of light at the time of emission from the polarization beam splitter can be maintained. Therefore, a system having a short optical path length, for example, S-polarized light reflected by the polarization beam splitter is reflected by the phase difference film to P
The amount of light that is converted into polarized light and enters the liquid crystal panel is approximately the same as the amount of light that enters the liquid crystal panel, and a stereoscopic image with a well-balanced brightness of the left and right images is obtained.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a liquid crystal projector (image projection unit) used in the present invention. The same parts as those in the conventional example are designated by the same reference numerals.

As shown in FIG. 1, the liquid crystal projector (image projection unit) of the present invention includes a lamp 2 and a reflector 3.
The light emitted from the light source unit 1 composed of is given to the polarization beam splitter 4. As described above, the polarization beam splitter 4 causes S
The polarized light is reflected, the P-polarized light is transmitted, and is polarized and separated into the left-eye projection light and the right-eye projection light. S reflected
Polarized light is converted to 9 by the retardation film (1/2 wavelength plate) 5.
The 0-degree polarized light is rotated to become P-polarized light, which is given to the liquid crystal unit 11 for the right eye in this embodiment. The liquid crystal unit 11 includes an incident side polarization plate 11a and a liquid crystal panel 11
b, the polarizing plate 11c on the exit side, and the P-polarized light from the retardation film 5 passes through the polarizing plate 11a on the entrance side and then the liquid crystal panel 11
It is incident on b and is further given to the projection lens 13 via the exit side polarization plate 11c. Then, the projection lens 13 projects an image on the screen.

On the other hand, the P-polarized light which has passed through the polarization beam splitter 4 is given to the liquid crystal unit 12 while maintaining the light quantity thereof via the relay lens 15 having the focal length (f ... f / 2 ... f). In this embodiment, the optical path that passes through the polarization beam splitter 4, is reflected by the reflection mirror 6 and reaches the liquid crystal panel unit 12, is reflected by the polarization beam splitter 4, and reaches the liquid crystal panel unit 11 through the phase difference film 5. Greater distance. for that reason,
A relay lens 15 is arranged on the long optical path side leading to the liquid crystal panel 12 for the left eye.

The relay lens 15 is, for example, a first lens 15a having a focal length of 100 mm, a second lens 15b having a focal length of 50 mm, and a third lens 1 having a focal length of 100 mm.
5c.

The P-polarized light that has passed through the relay lens 15 maintains the quantity of light, and the incident side polarization plate 12 of the liquid crystal unit 12 is maintained.
The distance between the optical axes from the projection lens 13 via the liquid crystal panel 12a, the liquid crystal panel 12b, and the emission side polarization plate 12c is, for example, 195 mm,
That is, the projection lens 14 is provided (65 × 3 mm) apart, and the projection lens 14 projects an image on the screen.

In the case of this embodiment, the second lens 15b is arranged at a position 100 mm away from the first lens 15a, and the third lens 15c is further arranged at a position 100 mm apart, and all lenses are AP coated ( Anti-reflection coating) is applied.

Further, in the case of this embodiment, the second lens 1
The reflection mirror 6 is arranged between the 5b and the third lens 15c.

The relay lens 15 is generally composed of an ideal focal length (f ... f / 2 ... f). In consideration of the above, it is possible to make the focal length of the second lens 15b larger than f / 2, for example. The arrangement position in this case is the same as the above case.

As in the conventional example shown in FIG. 2, the screen has a structure in which lenticular plates are installed on the front and back sides via a diffusion layer, and the lenticular plate arranged on the projector side allows the screen to be striped once. The left and right images are separated again by the lenticular plate that is formed as an image and is placed on the observer side, the left eye image is observed by the observer side left eye, and the right eye image is observed by the right eye. You can see.

As the screen, the lenticular plate arranged on the projector side may be omitted, and a parallax barrier may be used instead of the lenticular plate for separating left and right images.

[0029]

As described above, according to the present invention, in a stereoscopic image display device having a one-lamp structure using a polarization beam splitter, the distance from the light source to the liquid crystal panel for the left eye image and the liquid crystal for the right eye image. It is possible to provide a stereoscopic image device in which the light amounts of the two are substantially equalized and the luminance balance is good without performing an optical arrangement such that the distances to the panels are equalized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a liquid crystal projector (image projection unit) used in the present invention.

FIG. 2 is a configuration diagram showing a conventional projection type stereoscopic image display device of a double lenticular system.

FIG. 3 is a configuration diagram showing an image projection unit using a conventional polarization beam splitter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source part 2 light source lamp 3 reflector 4 polarization beam splitter 5 retardation film 6 reflection mirror 11 liquid crystal unit 11a incident side polarization plate 11b liquid crystal panel 11c emission side polarization plate 12 liquid crystal unit 12a incident side polarization plate 12b liquid crystal panel 12c emission side polarization Plate 13 Projection lens 14 Projection lens 15 Relay lens 15a First lens 15b Second lens 15c Third lens

Claims (2)

[Claims] 1. An image projection unit, a screen unit on which an image from the image projection unit is formed, and optical means for separating left and right images arranged on the viewer side of the screen unit.
In the stereoscopic image display device including the above, the image projection unit includes a liquid crystal panel that forms an image for the left eye, a liquid crystal panel that forms an image for the right eye, and light source light that is projection light for the left eye and projection for the right eye. A polarizing beam splitter for splitting into light, and a relay lens arranged on the optical path side of a long optical path for guiding the projection light split by the polarizing beam splitter to the liquid crystal panels for the right eye and the left eye, respectively, A stereoscopic image display device characterized in that projection light beams separated by a polarization beam splitter are incident on the liquid crystal panel for the right eye and the liquid crystal panel for the left eye with the same light amount and projected on a screen portion by a projection lens. 2. The stereoscopic image display device according to claim 1, wherein the relay lens is composed of three lenses, and each lens is provided with an antireflection coating.