JPH03284741A - Reflection type screen - Google Patents

Abstract

PURPOSE:To lighten an entire screen by forming embossing in a state where groove-shaped cuts, whose inner surface is a curved surface, are juxtaposed in a light reflecting layer and making a diffusing angle from the focal point of each cut to the cut larger than the projecting angle of a light source. CONSTITUTION:The embossing 4 is formed in the light reflecting layer 2 in the state where the groove-shaped cuts 3, whose inner surface is a curved surface, are juxtaposed. The diffusing angle theta2 from the center (f) of the curvature of the cut 3 to the end of cut from a position(the center of the cut) corresponding to the center (f) is set larger than the light projecting degree of the light source 5. Thus, the radius of curvature R becomes small and the surface of each cut 3 right angle to the light source side becomes large at its right and left parts. Therefore, reflection from the horizontal direction of the reflection type screen 1 to the central part becomes much and the entire screen is uniformly lightened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reflective screen used for viewing projected images such as OHP or projection television.

[Conventional technology]

For example, OHP (overhead projector) is an image projection device used in schools and businesses.When projecting an image using OHP, it is usually projected onto a white wall or a screen with a white surface is used. It is being When an image is projected onto a white wall from a device such as an OHP, the surface of the white wall is white and matte (fine unevenness), so the projected light will be diffusely reflected on the white wall surface, making it difficult for the viewer to see. The projected image can be seen anywhere in front of the white wall.

In addition, when projecting onto a white wall, there is a problem that the image is dark, so with the white screen mentioned above, the white surface is embossed to give the reflected light a certain degree of directionality, so that the brightness of the image can be adjusted. It is designed to improve However, with the current white screen, this is not a noticeable improvement.

In order to further improve the brightness of the image, a reflective screen was developed that had beads lined up all over its surface. This reflective screen has a structure in which a reflective layer is provided on a base cloth, and transparent beads with light converging properties are arranged uniformly over the entire surface, or a reflective layer is provided in place of the white layer. There is also a reflective screen that is provided with a light reflective layer made of a material such as rabbit and has embossments formed on this light reflective layer.The light reflective layer is constructed by matting an aluminum matte surface or an aluminum vapor deposited surface. There is. As shown in FIG. 4, there is also a reflective screen 1 which has a configuration in which the light reflective layer 2 is further provided with cuts in the shape of a cylindrical outer peripheral surface and embossing 4 through which the cuts 3 extend vertically. Since a screen constructed using the transparent beads is expensive, the above-mentioned screen with a matte finish on the aluminum matte surface or aluminum evaporated surface, or a screen with embossing made by arranging cylindrical cuts in parallel is available. It was often used to widen the horizontal viewing angle.

[Problem to be solved by the invention]

By the way, in the above-mentioned reflective screen provided with an embossing formed by arranging cylindrical cuts in parallel, the central portion is bright and the peripheral portion is dark due to the reflection characteristics of the light reflective layer. For example, as shown in FIG.
When projecting by , the light is projected with the projection angle from the light source corresponding position to the side portion being θ (=9.5”), and the light enters at the angle θ at the periphery of the screen 1. This is because there is more light returning in the central part of screen 1 (there are many surfaces facing the light source in each cut to return the light to the light source side) (Figure 6 also shows the screen gain), and the screen area increases. In the surrounding area, the incident light is 19° (9,5°X2=1
This is because the number of surfaces that face each other to return the light to the light source decreases in each cut) at an angle of 9 degrees (in the direction where there is no observer) (in Figure 7, the screen (Gain is also shown).

As a solution to this problem, it is possible to greatly increase the light diffusion on the left and right sides in order to make the overall brightness uniform, that is, to make the embossed shapes finer and to promote matting, but the brightness of the screen as a whole is uniform. However, since the degree of diffusion increases, the overall brightness decreases, which is an inconvenience.

Therefore, an object of the present invention is to make it difficult for outward reflection to occur around the periphery (left and right) of the screen in a reflective screen in which the light reflective layer is embossed with groove-shaped cuts with curved inner surfaces. The purpose is to make the entire screen uniform and brighter.

[Means to solve the problem]

The present invention has been made in consideration of the above-mentioned problems, and provides a reflective screen in which embossing is formed in a state in which groove-shaped cuts with curved inner surfaces are arranged in parallel on a light-reflecting layer.
The above-mentioned problem is solved by providing a reflective screen characterized in that the diffusion angle from the center of curvature of each cut to the cut end is made larger than the projection angle of the light source.

[For production]

In conventional reflective screens, embossing is provided on the light reflective layer so as to pass through the screen in the vertical direction. In this conventional reflective screen, the radius of curvature R of the embossed cuts is large, and each cut in the center of the screen has many surfaces that are perpendicular to the light source, but as mentioned above, cuts in the left and right parts are not perpendicular to the light source. As a result, reflection toward the center was reduced on the left and right sides.

Therefore, focusing on the fact that the large radius of curvature reduces the number of surfaces facing the light source on the left and right sides, in the present invention, the diffusion angle from the center of curvature in the cut to the cut end is made larger than the projection angle. As a result, the radius of curvature of the cut becomes smaller, and more surfaces are perpendicular to the light source on the left and right sides.

〔Example〕

Next, the present invention will be explained in detail based on the embodiments shown in FIGS. 1 to 3.

That is, in the present invention, as shown in FIG. 1, from the center f of the curvature of the cut 3, the position (
The diffusion angle θ2 from the center of the cut to the end of the cut is set to be larger than the projection angle θ, 4 of the light source 4. As a result, even if the cut pitch P is the same as before, since θ2>θ1, the radius of curvature R becomes small, and in each cut 3, there are many surfaces on the left and right sides that are perpendicular to the light source side. Become. Therefore, there is more reflection from the lateral direction to the center of the screen 1, making the whole screen uniform and brighter.

In the above-mentioned embodiments, the light-reflecting layer is formed by aluminum vapor deposition, but the material of this light-reflecting layer is not limited, and various inks such as burl ink and silver ink can be used. Also, as the shape of the cut that becomes the reflective surface (not just the curvature surface of the outer circumferential surface of the cylinder)
As shown in FIG. 2, the inner surface may have an elliptical curved shape, or as shown in FIG. 3, the inner surface may have a parabolic curved shape.

〔Effect of the invention〕

As explained above, according to the present invention, the reflective screen is formed by forming embossments on the light reflective layer with cleaning cuts with curved inner surfaces arranged side by side, and each cut is adjusted according to the projection angle of the light source. Since the diffusion angle from the focal point to the cut is increased, each cut of the emboss has many surfaces facing at right angles to the light source side on the left and right sides of the screen. Therefore, there is less reflection outward from the periphery (left and right) of the screen, and more reflection toward the center, making the entire screen uniform and brighter, making it difficult to compare with expensive screens made using transparent beads. It has excellent practical effects, such as the ability to obtain similar effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a cross section of an embodiment of a reflective screen according to the present invention, FIG. 2 is an explanatory diagram showing an embodiment in which the cut inner surface has an elliptical curved shape, and FIG. 3 is an explanatory diagram showing an embodiment in which the cut inner surface is parabolic. An explanatory diagram showing an embodiment exhibiting a curved surface shape, FIG. 4 is an explanatory diagram showing a cross section of the conventional example, FIG. 5 is an explanatory diagram showing a projection state with respect to the conventional example, and FIG. 6 is a central part of the conventional example FIG. 7 is an explanatory diagram showing a state in which the reflection toward the outside of the peripheral portion is large in a conventional example. 1... Reflective screen 2... Light reflective layer 3... Cut 4... Emboss 5... Light source θ,...・・Projection angle θ2・・・・・・Diffusion angle

Claims (4)

[Claims] (1) In a reflective screen in which embossments are formed on a light reflective layer with groove-shaped cuts having curved inner surfaces arranged side by side, each of the cuts is determined according to the projection angle of the light source.
A reflective screen characterized by a large diffusion angle from the center of curvature to the cut end. (2) The reflective screen according to claim 1, wherein the inner surface of the cut is provided in the shape of a cylindrical outer peripheral surface. (3) The reflective screen according to claim 1, wherein the inner surface of the cut is provided in the shape of an elliptical curved surface. (4) The reflective screen according to claim 1, wherein the inner surface of the cut is provided in a parabolic curved shape.