JP2000035616A - Screen sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen sheet by which high brightness and high contrast are realized by suppressing the reflection of external light without lowering the efficiency of light. SOLUTION: A light shielding layer 4 which is obtained by forming aperture parts 41 at an emitting surface side and which does not suppress the efficiency of the light optically made incident from some fixed direction is arranged at a microlens layer 3 obtained by arranging optically random convex lenses 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen sheet for displaying images used in a liquid crystal rear projection television, a CRT rear projection television, or the like.

[0002]

2. Description of the Related Art A screen generally used in a rear projection television is a lenticular screen type with a black stripe.

An optical system of a conventional liquid crystal rear projection television will be described with reference to FIG. Light having a certain angle is emitted from the projection lens 81 and is changed from a certain angle into parallel light by the Fresnel sheet 82. The light converted into parallel light is diffused by the lenticular sheet 83, and the light L having a certain viewing angle becomes an image and is projected on the eyes E of the user. The surface of the lenticular sheet 83 facing the user forms a black stripe (light-shielding portion) 84, which suppresses the reflection of external light, thereby increasing the contrast in the image.

Here, the conventional lenticular sheet 83 will be described more specifically with reference to FIG. The shape of the lenticular sheet 83 is such that a bi-convex lens 85 in the shape of a cylinder has a stripe shape in the vertical direction with respect to the user's eyes, and a black stripe 84 on the user's eye side.
Are formed.

The lenticular sheet 83 is viewed from the top in FIG.
An optical point will be described with reference to FIG. As shown in the figure, a parallel light composed of a transparent oil / fat layer 91, a resin layer 92 containing a diffusing agent, and a black stripe 84 is obtained through a Fresnel sheet 82 and is incident light IL.
As a result, the light enters the convex lens 85 of the lenticular sheet 83, is focused in the lenticular sheet 83, and is diffused as the outgoing light OL by the diffusing agent-containing resin layer 92 constituting the outgoing-side convex lens 85.

In the biconvex lens shape shown in FIG. 10, the convex lens on the incident side has a larger shape than the convex lens on the output side. This is because a black stripe 84 for suppressing external light reflection is formed on the output side. At the same time, the structure does not deteriorate the light efficiency. Further, the biconvex kamaboko lens shape controls the horizontal viewing angle characteristic, and the vertical viewing angle characteristic is controlled by the resin layer 92 containing the diffusing agent.

As described above, in the conventional lenticular sheet, the biconvex kamaboko lens shape is formed in the vertical direction (stripe shape) as viewed from the user side, and the lens pitch is physically or manufacturingly reduced. There are limitations,
The effect of moiré in response to the increase in the number of pixels (higher resolution) is large, and the viewing angle characteristics are particularly narrow in the vertical direction because the viewing angle is controlled by the diffusion agent alone. In addition, the black stripe shape has poor light efficiency and high reflectance (high contrast) due to external light.

[0008]

In the above-mentioned conventional lenticular sheet, the lens pitch has a limit in miniaturization physically or in terms of manufacturing, and the effect of moire is large in response to the increase in the number of pixels (high resolution). In particular, the vertical direction was narrow because the viewing angle was controlled by the use of a diffusing agent, and the black stripe shape had poor light efficiency and high reflectance (high contrast) due to external light.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a screen sheet capable of realizing high brightness and high contrast by suppressing reflection of external light without reducing light efficiency.

[0010]

In order to solve the above-mentioned problems, a screen sheet according to the present invention has a layer in which lenses having optically random convex shapes are arranged or elliptical or spherical lenses are arranged. A microlens array sheet array is formed, and a light-shielding layer that does not suppress the efficiency of incident light optically incident from a certain direction is formed on an emission surface.

According to the above-mentioned means, it is possible to display a wide viewing angle, high brightness, high contrast, and high resolution moireless image as a screen of a liquid crystal rear projection television and a CRT rear projection television.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram for explaining the first embodiment of the present invention. In FIG. 1, light having a certain angle is emitted from a projection lens 1, converted from a certain angle into parallel light by a Fresnel sheet 2, and irradiated to a microlens layer 3. In the microlens layer 3, light is diffused, and light L having a certain viewing angle becomes an image and is projected on the user's eyes E. A light-shielding portion 4 is formed in the microlens layer 3 facing the user to suppress the reflection of external light, thereby increasing the contrast in an image.

The microlens layer 3 and the light shielding portion 4 will be further described with reference to the perspective views of FIG. 2 viewed from the emission side and FIG. 3 viewed from the incidence side. The microlens layer 3 includes a randomly convex lens 31 and a lens layer 32 from the incident side.
The light shielding portion 4 has a random opening 41 for emitting the incident light.

The optical relationship between one convex lens out of the random convex lens 31 and the random opening 41 and the opening will be described with reference to FIG. That is, when parallel light is incident on the microlens layer 3 as shown in the drawing, the convex lens of the lens 31 first focuses on the opening 41, and the diffused light is used as the outgoing light OL as a certain field of view. Light (image) having angular characteristics (horizontal / vertical) reaches the user's eyes E. The lens layer 32 has a wide divergence angle, and the viewing angle characteristics are widened by using materials having different refractive indexes between the lens 31 and the lens layer 32. Here, the shape of the lens 31 is an elliptical convex lens shape as means for providing a difference between the horizontal and vertical viewing angles.

By randomly forming such a sheet having an optical relationship between one lens and an opening, the area of the opening can be made smaller and the area of the light-shielding portion can be made larger, and the sheet can be formed at a fine pitch. This makes it possible to realize a microlens array sheet having a wide viewing angle, high efficiency, high contrast (low external light reflection characteristics), and high resolution moireless.

In the case where the lens and the opening are formed without using a mold by, for example, applying or injecting fine particles,
Finer pitch is possible.

FIG. 5 is a top view of a microlens layer for explaining a second embodiment of the present invention.
In this embodiment, the plane of incidence of the parallel light obtained through the Fresnel sheet 2 has a flat shape.

That is, as shown in FIG. 5, the micro-lens layer 3 is formed by integrally forming a spherical or elliptical lens 35 between the lens layers 33 and 34. Light (image) having a certain viewing angle characteristic (horizontal / vertical) reaches the user's eyes by passing through the layer 33, the lens 35, and the lens layer 34 and focusing on the opening 4.
The lens layers 33 and 34 and the lens 35 are made of materials having different refractive indices so as to widen the viewing angle characteristics.

The lens layer 53 is formed of an elliptical sphere in order to provide a difference between the horizontal and vertical viewing angles. In this case, the lens layers 33 and 34 have the same material and the same refractive index, and only the lens 35 has a different refractive index.

FIG. 6 is a top view of a microlens layer for explaining a third embodiment of the present invention.
In this embodiment, a diffusion sheet 61 is attached to the end of the emission side in the microlens layer 3 and the light shielding portion 4. The incident light IL is emitted as the outgoing light OL through the opening 4 and the diffusion sheet 61. At this time, the viewing angle characteristics of the diffusion sheet 61 can be made wider.

FIG. 7 is a top view of a microlens layer for describing a fourth embodiment of the present invention.
The light shielding part 4 and the opening 41 are formed by using the micro lens layer 3.
First, a light-shielding sheet 71 is attached or applied to the exit surface side of the microlens layer 3 as shown in FIG. Next, as shown in (b), similarly to the incident light IL actually used, for example, light perpendicular to the microlens layer 3 is irradiated on the light-shielding sheet 71 with the irradiation light 7L, so that the light-shielding sheet 71 is irradiated. The opening 41 is formed by hollowing, a so-called manufacturing method called self-alignment. In this case, it is indispensable to have the same conditions as the incident light IO actually used and to configure the microlens layer 3 so as to focus on the exit surface.

In this embodiment, even if the lenses are formed randomly, an aperture can be formed as long as it is optically focused by the light-shielding layer, realizing high brightness and high contrast. Becomes possible.

[0023]

As described above, according to the screen sheet of the present invention, it is possible to provide a screen sheet for displaying an image with high brightness and high contrast by suppressing the reflection of external light without lowering the light efficiency. Become.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a first embodiment of the present invention.

FIG. 2 is a perspective view for explaining the microlens layer of FIG. 1 when viewed from an emission side.

FIG. 3 is a perspective view for explaining the microlens layer of FIG. 1 when viewed from an incident side.

FIG. 4 is a top view for describing the microlens layer of FIG. 1 in more detail;

FIG. 5 is a top view for explaining a second embodiment of the present invention.

FIG. 6 is a top view for explaining a third embodiment of the present invention.

FIG. 7 is a top view for explaining a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram for explaining an optical system of a conventional liquid crystal rear projection television.

FIG. 9 is a perspective view illustrating a lenticular sheet used in FIG. 8;

FIG. 10 is a cutaway top view of FIG. 9;

[Explanation of symbols]

3 ... micro lens layer, 31, 35 ... lens, 32,3
3, 34 ... lens layer, 4 ... light shielding part, 41 ... opening part, 61
... Diffusion sheet, 71 ... Light shielding sheet, IL ... Incident light, OL
... Outgoing light.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Saito 1-9-2 Hara-cho, Fukaya-shi, Saitama Prefecture Inside the Toshiba Fukaya Plant (72) Inventor Tsukasa Sakamoto 1-9-1-2 Harara-cho, Fukaya-shi, Saitama No. F-term in Toshiba Fukaya Plant (reference) 2H021 BA22 BA27 BA28

Claims (6)

[Claims] 1. A microlens array in which a layer in which optically random convex lenses are arrayed is formed, and the microlens array is adhered to the microlens array, and is optically incident from a certain direction formed on an exit surface side. A screen sheet comprising a light-shielding layer that does not suppress the efficiency of incident light. 2. A microlens array sheet formed by laminating a layer in which lenses having optically random convex shapes are arranged and a layer having a different refractive index; A screen sheet comprising: a light-shielding layer that does not suppress the efficiency of incident light incident from a direction. 3. A microlens array sheet in which spherical or elliptical spherical particles having different refractive indices are randomly arranged in a lens layer; and a microlens array sheet bonded to the microlens array sheet and formed on an exit surface side. A light-shielding layer that does not suppress the efficiency of incident light that is optically incident from a certain direction. 4. A microlens array sheet having lenses in which spherical or elliptical spherical particles having different refractive indexes are randomly arranged between lens layers having different refractive indexes on a light incident surface side, A screen sheet comprising: a light-shielding layer that is bonded to a microlens array sheet and that does not suppress the efficiency of incident light that is optically incident on a light exit surface from a certain direction. 5. The screen sheet according to claim 1, wherein a sheet that diffuses light is formed on the observation surface side of the microlens array sheet. 6. The microlens array sheet is formed by a self-alignment method in order to form a light-shielding layer on an exit surface in accordance with a microlens sheet that does not suppress the efficiency of incident light optically incident from a certain direction. The screen sheet according to any one of claims 1 to 4, wherein the screen sheet is formed by: