JPH0521073Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a rear projection screen used in a projection device.

[Conventional technology]

As a projection device such as a projector, an image is displayed using a display body such as a liquid crystal display panel or a cathode ray tube, and the displayed image of this display body is projected onto a translucent rear projection screen from the back side, and this screen projection image is created. There are some that allow you to observe from the front side of the screen.

FIG. 5 shows the principle of this type of rear projection type projector, and here shows one that uses a liquid crystal display panel as a display body. To explain the configuration of this rear projection type projector, in FIG. 5, 1 is a transmissive dot matrix liquid crystal display panel that displays images such as television images, and 2 is arranged behind the liquid crystal display panel 1. The light source 2 is composed of a light source lamp 3 and a reflector 4 that reflects the emitted light from the light source lamp 3 toward the liquid crystal display panel 1. Note that the reflector 4 is a parabolic mirror reflector that reflects the emitted light from the light source lamp 3 as parallel light. 5 is a projection lens arranged in front of the liquid crystal display panel 1, and 6 is a rear projection screen. This screen 6 is made of a transparent resin sheet such as acrylic resin.
The front surface (observation surface) is a light diffusing surface 6a.
The light diffusing surface 6a may be formed by, for example, making the front surface of the screen a lenticular lens surface for light diffusing in which a large number of finely wide lens surfaces are continuous, as shown in FIG. 6, or by covering the front surface of the screen with a light diffusing sheet or the like. It is formed by Also, 7 is the screen 6 above.
A Fresnel lens for light beam correction (circular Fresnel lens) is provided in parallel with the screen 6 so as to closely face the back side (light incident surface side) of the screen 6 .

This rear projection type projection device has a liquid crystal display panel 1
The display image of
The light that enters the liquid crystal display panel 1 and passes through the liquid crystal display panel 1 is projected onto the screen 6 side while spreading through the projection lens 5, and is converted into parallel light perpendicular to the screen 6 surface by the light beam correction Fresnel lens 7. Rear projection screen 6 after being corrected to
The light enters from the back side of the screen, passes through the screen 6, and is observed from the front side of the screen. The light diffusing surface 6a on the front of the screen is for diffusing the light that has passed through the screen 6.If the front of the screen is used as the light diffusing surface 6a, the light that has passed through the screen 6 will be diffused over a wide range in front of the screen. The viewing angle of the screen-projected image can be increased. The configuration of this rear projection type projector is similar to that using a cathode ray tube as a display body (however, the light source 2 is not provided).

By the way, the above-mentioned rear projection type projection apparatus includes one that uses a display body that displays a monochrome image (generally a black and white image) to project a monochrome image onto the screen 6, and one that uses a display body that displays a color image. There are devices that project a color image onto a screen 6, but conventionally, all of these projection devices have a rear projection system as shown in FIG. using a screen.

[Problem that the invention attempts to solve]

However, traditional rear projection screens
As mentioned above, since the incident light from the back side is directly transmitted to the front side, the screen projection image observed from the front side of the screen is an enlarged image of the display image on the display body. When this screen is used in a projection device for projecting color images, there is a problem in that the color images projected onto the screen end up being images with poor color reproducibility. This is because displays that display color images (such as liquid crystal display panels or cathode ray tubes) generally display pixels of the three primary colors of red, green, and blue arranged alternately, and the colors of the red, green, and blue pixels are mixed together. This is because a color image is displayed by creating color pixels using a 3D display, and when a color image displayed on this display is projected onto a conventional screen, the red pixels incident on the screen 6 as shown in FIG. The light R, the green pixel light G, and the blue pixel light B pass through the screen 6 as they are, and the screen projection image observed from the front of the screen also becomes an image in which red, green, and blue pixels are arranged alternately.
If the three primary colors of red, green, and blue are poorly mixed, the color image projected onto the screen will be an image with poor reproducibility.

This idea was made in view of the above-mentioned circumstances, and its purpose was to create a color image projected from the back side in which red, green, and blue pixels are arranged alternately, with good color mixing. It is an object of the present invention to provide a rear projection screen that can be observed from the front side as a highly reproducible image.

[Means to solve problems]

The rear projection screen of this invention includes a prism forming a first incident plane, a second incident plane, and a third incident plane on the incident side of the screen, and includes a prism for forming a red, green, and red color image projected onto the screen. , blue parallel pixel light is incident on the incident plane of each of the prisms, and adjacent red, green,
The pixel light on both sides of the blue pixel light is refracted toward the center pixel light, and the red, green, and blue pixel lights are superimposed on the projection surface of the screen.

[Effect]

In other words, the rear projection screen of this invention is
The red, green, and color images projected from the back side of the
The blue pixel light is superimposed through each prism surface of the light refracting surface, and if the red, green, and blue pixel lights are superimposed in this way,
Since the light transmitted to the front side of the screen becomes color pixel light in which red, green, and blue pixel lights are overlapped, according to this rear projection screen, the red, green, and blue pixels projected from the back side are Alternating color images can be observed from the front side as highly reproducible images with good color mixing.

〔Example〕

An embodiment of this invention will be described below with reference to FIG. In addition, Fig. 1 is an enlarged view of a part of the screen (corresponding to part A in Fig. 5), and 7 in the figure is a light beam correction device placed on the back side (light incident surface side) of the screen. It is a Fresnel lens for use.

This rear projection screen has a trapezoidal cross section with a flat surface 12a in the center and inclined rising surfaces 12b and 12c on both sides, on the back surface (light entrance surface) of a screen body 10 made of transparent resin such as acrylic resin. The prism surfaces 12, 12 form a continuous light refracting surface 11, and the screen body 1
A light diffusing layer 13 is formed on the front surface (observation surface) of the screen 0, and the light refractive surface 11 on the back surface is formed by molding the screen body 10 by hot pressing a transparent resin sheet, extruding a transparent resin, or injection molding. The light diffusion layer 13 on the front side is integrally formed on the back side of the screen body 10.
It is formed by adhering a light-diffusing transparent resin sheet to the front surface using a transparent adhesive. In addition, each prism surface 12, 12 of the light refractive surface 11 on the back of the screen
are the central flat surface 12a and the rising surfaces 12 on both sides.
The widths of b and 12c are respectively the color images displayed on a display body (not shown) such as a liquid crystal display panel or a cathode ray tube, and enlarged and projected onto a screen by a projection lens (not shown), such as a full color image of red, green, and blue. In addition to matching the widths of the pixel lights R, G, and B, the inclination angles of the rising surfaces 12b and 12c on both sides are adjusted so that the light incident on these rising surfaces 12b and 12c (the screen surface corrected by the Fresnel lens 7 for beam correction) The angle is such that parallel light (perpendicular to the center) is refracted so that it intersects with the light incident on the screen through the central flat surface 12a at the light diffusion layer 13 in front of the screen. That is, each of the prism surfaces 12, 12 of the light refractive surface 11 has an adjacent red color image projected on the screen,
Among the green and blue pixel lights R, G, and B, the central pixel light (green pixel light G in the figure) that is incident on the central flat surface 12a is allowed to proceed straight as it is, and is directed to the rising surfaces 12 on both sides.
The pixel lights on both sides (in the figure, red pixel light R and blue pixel light B) entering b and 12c are refracted toward the center pixel light side, and the red, green, and blue pixel lights R, G, and B are screened. The red, green, and blue pixel lights R, G, and B that intersect in the light diffusion layer 13 are overlapped in the front light diffusion layer 13, and are diffused in the light diffusion layer 13.
Red, green, and blue pixel lights R, G, and B are superimposed to form composite color pixel light RGB, which is emitted to the front side of the screen.

That is, the rear projection screen transmits the red, green, and blue pixel lights R, G, and B of the color image projected from the rear side of the screen through the prism surfaces 12 and 12 of the light refracting surface 11 formed on the rear surface of the screen. By superimposing the red, green, and blue pixel lights R, G, and B in this way, the light that passes through the front side of the screen becomes the red, green, and blue pixel lights. This rear projection screen produces a color image with alternating red, green, and blue pixels projected from the rear side, with high reproducibility and good color mixing. It can be observed as a pixel from the front side.

2 to 4 show other embodiments of this invention, and the embodiment shown in FIG. 2 is the rear projection screen of the embodiment shown in FIG.
In front of the light diffusion layer 13, each color pixel light
In this embodiment, black stripes 14, 14 are formed by printing light-absorbing paint to partition the output surfaces of RGB and RGB.
Since the external light can be absorbed by the screen, it is possible to prevent external light from being reflected on the front of the screen and making it difficult to see the screen projected image.In addition, the black stripe 14, 14, the screen projection image can be a clear color image without color shift or color bleeding.

Further, in the embodiment shown in FIG. 3, a lenticular lens surface 15 for light diffusion, in which a large number of fine width lens surfaces 15a, 15a are continuous, is formed on the front surface of the light diffusion layer 13 in front of the screen. According to the rear projection screen of this embodiment, the light emitted to the front side of the screen is directed to the lenticular lens surface 1.
5, it is possible to widen the viewing angle of the screen projected image by spreading the light over a wide range.

Furthermore, in the embodiment shown in FIG. 4, each color pixel light is
A lenticular lens surface where the parts corresponding to the RGB, RGB output surfaces are lens surfaces 15a, 15a, and the part between these lens surfaces is a flat surface, and a light-absorbing paint is printed on this flat surface to form a black stripe 14. 15, and the rear projection screen of this embodiment has the effects of both the embodiment of FIG. 2 and the embodiment of FIG. 3 described above.

[Effect of idea]

The rear projection screen of this invention refracts the pixel lights on both sides of the adjacent red, green, and blue pixel lights of the color image projected onto the screen to the central pixel light side, thereby refracting the red, green, and blue pixels. Since the light refracting surface is formed by a continuous number of prism surfaces that superimpose light, it is possible to create a color image with alternating red, green, and blue pixels projected from the back side, with high reproducibility and good color mixing. The image can be viewed from the front side.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a part of a rear projection screen showing one embodiment of this invention, FIGS. 2 to 4 are sectional views of a part of a rear projection screen showing other embodiments of this invention, and FIG. This figure is a principle diagram of a rear projection type projector, and FIG. 6 is an enlarged sectional view of section A in FIG. 5 showing a conventional rear projection screen. 10...Screen body, 11...Light refractive surface,
12... Prism surface, 12a... Flat surface, 12
b, 12c...Rising surface, 13...Light diffusion layer, 1
4... Black stripe, 15... Lenticular lens surface, 15a... Lens surface.

Claims (1)

[Scope of utility model registration request] A rear projection screen that allows a color image projected from the rear side and in which red, green, and blue pixels are arranged alternately to be observed from the front side, and has a first incidence plane, a second incidence plane, and a second incidence plane on the incidence side of the screen. 3, and the parallel pixel lights of red, green, and blue of the color image projected on the screen are incident on the incidence plane of each of the prisms,
refracting pixel lights on both sides of adjacent red, green, and blue pixel lights of the color image toward a central pixel light side, and superimposing the red, green, and blue pixel lights on the projection surface of the screen; A rear projection screen featuring