JPS592033A - Rear projection screen - Google Patents

Abstract

PURPOSE:To obtain an image having good luminance and contrast by forming a rear projection screen consisting of renticular lenses which have a prescribed width and are placed to face to each other, and emitting only the light projected from the renticular lenses on the incident side from the renticular lenses on the exit side. CONSTITUTION:Renticular lenses 8, 8' and 3 are provided respectively on the incident side and exit side of a rear projection screen 1. The projection light 4 by two different two-dimensional images is made incident to the lens 8 on the incident side and the other lens 8'. The width of each outlet side lens 3 is set at 2 times of the width of the incident lenses 8, 8', and the lenses are disposed to face to each other. The light 4 from the lens 8 is the exit light 6 directing from the lens 3 toward the left eye direction and the projection light 5 from the other lens 8' is the exit light 7 directing to the right eye direction. The full energy of the projection light which is made incident to the lenses 8, 8' is emitted from the lens 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear projection screen suitable for a projection stereoscopic television apparatus.

2. Description of the Related Art Conventionally, a technique is known in which a television image is projected onto a screen and displayed in three dimensions to obtain an enlarged three-dimensional television image.

Such technology simultaneously captures images of a subject from different positions,
Different two-dimensional television images are projected onto a television receiver using the respective video signals obtained, and the television images are projected onto a screen and enlarged for display, so that one television image can be viewed with one eye. Then, a stereoscopic image is displayed so that the other television image can be observed with the other eye.

By the way, the screen used in such a projection type stereoscopic television device is provided with a lenticular lens on its surface, and the television image projected on the screen can be viewed with one eye and the other eye. The image is separated into two images. As such a screen, there is a rear projection screen through which the projection light of the projected television image is transmitted and the screen can be observed from the side opposite to the receiver side.

FIG. 1 is a partial sectional view showing an example of a conventional rear projection screen, in which 1 is a rear projection screen, 2 is a diffuser plate, 3.3' and 5'' are lenticular lenses, and 4 and 5 are projection screens, respectively. Lights 6 and 7 are emitted lights.

In the figure, projection light 4 (hereinafter referred to as left projection light) is an image projected on a television receiver (not shown) that is to be observed with the left eye, and projection light 4 is an image that is to be observed with the right eye. 5 (hereinafter referred to as right-side projection light) enters different positions of the diffusion plate 2 of the rear projection screen 1 and is diffused by °C.

A part of each of the diffused projection lights 4 and 5 is emitted from the same lenticular lens 3 as emitted lights 6 and 7. The emitted light 6 is emitted toward the left eye, and the emitted light 7 is emitted toward the right eye. Therefore, the viewer can observe the stereoscopic television image by capturing the emitted light beams 6 and 7 with the left and right eyes, respectively.

By the way, the diffuser plate 2 is provided to direct the projection lights 4 and 5 in the direction of the same lenticular lens 3 and to make the emitted light 6.7 exit in different directions, but at the same time, This also causes the projection lights 4 and 5 to be diffused, causing light to be directed in undesired directions. For this purpose, the projection light 4 that originally has to be emitted through the lenticular lens 3
, 5 should not be ejected from the adjacent lenticilla lens 5.
The amount of light emitted from t and 3'' is also partially emitted, and the amount of light from 7 is reduced, resulting in a reduction in brightness and contrast and undesirable light in the displayed 3D television image. contamination, etc., resulting in deterioration of image quality.

An object of the present invention is to provide a rear projection screen that eliminates the drawbacks of the prior art described above, prevents the emission of undesired light from the lenticular lens, and improves the image quality of displayed stereoscopic television images. is to provide.

In order to achieve this object, the present invention comprises a plurality of lenticular lenses, and projects light from one different two-dimensional image (where LE is an integer greater than or equal to 2) into a plurality of lenticular lenses. a first means for making the light incident on the lenticular lens; and a first means for emitting the projection light in different directions for each of the two-dimensional images, the first means being composed of a plurality of lenticular lenses having a width twice that of the lenticular lens of the first means. 2
and a means for emitting only the projection light from the different lenticular lenses of the first means for each lenticular lens of the second means.

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

FIG. 2 is a partial sectional view showing an embodiment of the rear projection screen according to the present invention, in which 8 and 8' are lenticular lenses, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, lenticular lenses are provided on the entrance side and exit side of the rear projection screen 10, respectively. In this embodiment, a case will be explained in which a three-dimensional image is displayed using two different two-dimensional images (n=2), and the projection light 4 from one two-dimensional image is incident on the incident side lenticular lens 8, and the other The projection light 5 from the two-dimensional image is incident on the adjacent lenticular lens 8'. In this way, the projection light from each two-dimensional image is incident on the lenticular lenses at different intervals.

On the other hand, the width of the lenticular lens on the exit side is set to be the entire width of two adjacent lenticular lenses on the input side, that is, twice the width of the lenticular lens on the input side,
Furthermore, the center of the surface is arranged to face the center of the surface formed by the two lenticular lenses on the incident side. Therefore, the lenticular lens 5 on the exit side is arranged opposite to the lenticular lenses 8, 8' of the enclosure.

Therefore, the projection light 4 that has entered the lenticular lens 8 is
The light is once converged within the rear projection screen 1, and then diverges and exits from the lenticilla lens 3, becoming an emitted light 6 directed toward the left eye. On the other hand, the projection light 5 that has entered the lenticular lens 8' is once converged within the rear projection screen, and then diverges and exits from the lenticular lens 5 to become an output light 7 directed toward the right eye.

The lenticular lenses 8 and 8' are formed so that the positions of their focusing parts approach each other, and the lenticular lenses 3 cover the expanding range of the projection light diverging from these focusing parts. The arrangement of the Keira lens 3 is set.

Therefore, all of the energy of the projection light that has entered the lenticilla lenses 8 and 8' is emitted from the lenticilla lens 3, improving the brightness and contrast of the displayed stereoscopic image, and preventing unnecessary light from entering. image quality is greatly improved.

FIG. 3 is a partial sectional view showing another embodiment of the rear projection screen according to the present invention, in which 9 is a diffusion layer, and parts corresponding to those in FIG. 2 are given the same reference numerals.

In the figure, the diffusion layer 9 has a small diffusion angle and is arranged on a surface including the position where the light projected by the lenticular lens on the incident side is focused.

Lenticular lens 8.8'l? : Incident projection light 4.
The light beams 5 are focused on the diffusion layer 9, are slightly diffused and diverged by the diffusion layer 9, and are emitted as output lights 6 and 7 from the lenticular lens 3, respectively, as described above. The diffusion layer 9 also diffuses the projection light in the direction perpendicular to the plane of the paper, and therefore the field of view can also be expanded in the direction perpendicular to the image.

In this embodiment, the diffusion layer 9 also diffuses the projection light in a direction parallel to the plane of the paper, but the width of the irradiation area of the projection light on the diffusion layer 9 in the direction parallel to the plane of the paper is compared with the width of the lenticular lens 3. Since the projection angle is sufficiently small and the diffusion angle is also small, the projection light 8, 8' diffused by the diffusion layer 9 will not leak to the adjacent lenticular lenses 3', 3''.

FIG. 4 is a partial cross-sectional view showing still another embodiment of the rear projection screen according to the present invention, in which 10 is a light absorption section;
Reference numeral 1 denotes a projection light, and parts corresponding to those in FIG. 3 are given the same reference numerals, and some explanations will be omitted.

In this embodiment, four two-dimensional images obtained by imaging a subject (not shown) at four different locations are projected, and a three-dimensional image is displayed using the projection light from these images.

In FIG. 4, projection light 11 from four two-dimensional images is transmitted through different lenticular lenses 8, 8', 8, respectively.
"Ban", is focused and diffused by the diffusion layer 9, and exits from the lenticular lens 5.Lenticular lens 3
The width of the lenticular lens is 8.8', 8”,
As described above, the projection light incident on the lenticular lenses 8.8', 8'', and 8'' is emitted in different directions.

The diffusion layer 9 includes lenticular lenses 8.8', 8''.

A light absorbing section 10 is provided except for the portion irradiated with the focused projection light from 8#, and absorbs unnecessary incident light.

Therefore, the contrast of the displayed stereoscopic image is further improved, and the image quality is further improved.

FIG. 5 is a perspective view showing the rear projection screen in the embodiment shown in FIGS. 3 and 4, and corresponding parts are given the same reference numerals.

FIGS. 6(a) and 6(to) are block diagrams showing an example of a projection type stereoscopic television apparatus using the rear projection screen (FIG. 6) according to the present invention, where 12 is the subject% 13.14
is a television camera, 15 is a video mixing circuit, 16 is a pulse generator, 17 is a transmitter, 18 is a receiver, 19 is a cathode ray tube, 20 is a main lens, and 21 is a Fresnel lens, corresponding to Fig. 3. Parts are given the same reference numerals and some explanations are omitted.

First, in FIG. 6 (/4), the subject 12 is imaged by two television cameras 15.14 from different positions, and the television cameras 13.14 each output video signals representing different two-dimensional images. Obtained video mixing circuit 1
5. On the other hand, a pulse is generated from the pulse generator 16, and this pulse is supplied to the video mixing circuit 15.

The video mixing circuit 15 alternately outputs the video signals from the four television cameras 13 and 14 according to the supplied pulses.
A time-division multiplexed point-sequential video signal is obtained. This video signal is transmitted by the transmitter 17, received by the injured device 1B, and supplied to the cathode ray tube 19.

The two two-dimensional images mentioned above are displayed on the cathode ray tube 19, and each two-dimensional image is made up of every other picture element. That is, one two-dimensional image consists of discrete picture elements every other picture element, and the other two-dimensional image consists of discrete picture elements between the picture elements of the one two-dimensional image. Therefore, the projection positions of picture elements of each two-dimensional image on the cathode ray tube 19 are shifted.

Next, in Fig. 6 β), Brown c#
The two-dimensional images projected on the main lens 19 are enlarged by the main lens 20, and the Fresnel lens 14 is irradiated with projection light from these two-dimensional images. The Fresnel lens 21 converts the projected projection light into parallel light, and makes each projection light enter a separate lenticular lens of the rear projection screen 1 for each picture element on the cathode ray tube 19. For example, the projected light 4 from a given pixel in one two-dimensional image and the projected light 5 from a pixel in the other two-dimensional image horizontally adjacent to the image of the pixel are as follows:
The Fresnel lens 21 converts the light into parallel light, which is incident on the adjacent lenticular lenses 8 of the rear projection screen 1, respectively. Therefore, as mentioned above, a stereoscopic image is displayed on the rear projection screen 1.

As explained above, according to the present invention, it is possible to increase the amount of light emitted from each lenticular lens on the exit side and to prevent the mixing of undesired surface light, thereby improving brightness and contrast. The quality of the displayed stereoscopic image is greatly improved, and a rear projection screen with excellent functionality can be provided without the drawbacks of the prior art described above.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an example of a conventional rear projection screen, FIG. 2 is a partial sectional view showing an embodiment of a rear projection screen according to the present invention, and FIG. 3 is a partial sectional view showing an example of a rear projection screen according to the present invention. FIG. 4 is a partial sectional view showing still another embodiment of the rear projection screen according to the present invention, and FIG. 5 shows the entire rear projection screen shown in FIGS. 5 and 4. FIG. 6 is a perspective view showing an example of a projection type stereoscopic television display device using a rear projection screen according to the present invention. 1... Rear projection screen 3, 3', 5"... Lenticular lens 4.5...
・Projection light 6, 7... Output light 8.8', 8"
But...Lenticular lens 9...Diffusion layer
10...Light absorption part 1st circle - Figure 2 Figure 3 Figure 9 Figure 4 Ground 5

Claims (1)

[Claims] (1) Projecting a number of different two-dimensional images (wherein is an integer of 2 or more) obtained by imaging a subject from different positions, so that an enlarged three-dimensional image of the subject can be obtained. in the rear projection screen, a first means for projecting light from the plurality of two-dimensional images (from a plurality of lenticular lenses) into every other lenticular lens, which is different for each of the two-dimensional images; a second means for emitting the projection light in different directions for each of the two-dimensional images; The image quality of the three-dimensional image can be improved by emitting only the projection light from each lenticular lens having a different first means for each lenticular lens. Rear projection screen.