JPH052881Y2 - - Google Patents

Description

[Detailed explanation of the idea]

Purpose of invention

[Industrial application field]

The present invention relates to a diffusion filter that is used in combination with a single color or two or more color light emitting sources to form a matrix display.

[Conventional technology]

Single color or two or more color light sources (e.g. LED)
A device was invented in which a large number of these are arranged as one pixel, a light diffusion filter is placed in front of the pixel, and a display is created by blinking and/or changing the brightness of the light emitting source, and by changing the color for light emitting sources of two or more colors. It was done. Diffusion of light is necessary to spread the light from the light source and eliminate unevenness, but on the other hand, it causes a decrease in visibility due to blurring of the image outline, and in the case of multiple light sources, it also causes unevenness due to the position of the color. is added. Therefore, it has been proposed to use a diffusion filter in which a light-shielding material is applied to the surface of the filter so that a large number of pixels are formed in a matrix, as shown in FIG. Such filters are required to provide higher contrast and to be free of color bleeding.

[Problem that the invention attempts to solve]

An object of the present invention is to provide a diffusion filter provided with the above-mentioned light shielding material, which improves contrast, reduces image blurring, and provides a clear image. Structure of the idea

[Means to solve the problem]

The diffusion filter of the present invention is a diffusion filter 1 that constitutes a matrix display in combination with a light emitting source 2 as shown in FIG.
A light shielding material 12 is applied to form 1 in a matrix, W≧T・tanθ W: Pixel width T: Filter thickness θ: The transmittance of diffusely transmitted light is 1 of the transmittance of vertically transmitted light. It is characterized in that W, T, and θ are selected so that a diffusion angle relationship of /3 is established.

[Effect]

In a diffusion filter, the amount of light decreases as the diffusion angle, ie, the tilt from the vertically transmitted light, increases. Generally, in this type of display, if the difference in light intensity is three times or more, the contrast is good. According to the present invention, by setting the width W of the light shielding material that partitions adjacent pixels to T tan θ or more, the second
As shown in the figure, the intensity of the diffused light entering from adjacent pixels is reduced to less than 1/3, improving the contrast and clarity of the image.

[Embodiment]

If the width W of the light shielding material is too large, the pixel density will become coarse and the continuity of the pixels will be lost, and the entire display surface will become dark, so the pitch of the pixel arrangement cannot be made coarser than a certain level. Therefore,
There is a certain limit to the thickness T of the filter. On the other hand, if the filter is too thin, sufficient diffusion will not be achieved. There is also a certain favorable relationship between diffusion angle and transmittance. The specifications are determined in order to satisfy the above conditions, taking into consideration the mutual relationships among W, T, and θ as described above. Also, for example, if the thickness of the light shielding material is thick,
It is preferable that the thickness measured from the surface far from the light source 2 be T. Therefore, when the light shielding material is on the side of the light source, T does not include the thickness of the light shielding material, but when the light shielding material is on the opposite side of the light source 2, T includes the thickness of the light shielding material. The shape of the pixel, or in other words, the shape of the light-shielding material, is arbitrary, and is typically circular as shown in the figure, but may be shaped like a lattice. The light-shielding material may be placed on either the front or back surface of the filter, and may be formed by any method such as printing, injection molding, or pasting a die-cut sheet. In manufacturing the diffusion filter of the present invention, dyes and pigments are added to commonly used plastics, glass, ceramics, etc. as necessary to control light transmittance, and inorganic or organic light diffusing materials are added. A sheet that has been given light-diffusing properties by mixing particles, or by intentionally causing phase separation without using a light-diffusing material, or by applying lens processing or matte processing to the surface, is extruded or coated. It may be produced by means such as staining, pressing, melting, and sintering. Effects of the invention By applying the diffusion filter of the invention to a matrix display, contrast and image blurring are improved and clear images can be obtained. This filter is effective for both monochromatic light source displays and multicolor light source displays, but its significance lies in the fact that it sufficiently mixes colored light, reduces unevenness, and improves resolution and contrast. This is particularly large in multi-pixel displays where one pixel is a light source.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of the diffusion effector of the present invention. FIG. 2 is an enlarged sectional view illustrating the function of the diffusion filter of the present invention. 1... Diffusion filter, 11... Pixel, 12...
...shading material, 2... light source.

Claims (1)

[Claims for Utility Model Registration] (1) A diffusion filter 1 that constitutes a matrix display in combination with a light emitting source 2, in which a large number of pixels 11 are formed in a matrix on at least one surface of a light diffusion sheet. A light shielding material 12 is applied to the area, W≧T・tanθ W: Pixel width T: Filter thickness θ: Diffusion angle relationship such that the transmittance of diffusely transmitted light is 1/3 of the transmittance of vertically transmitted light A diffusion filter characterized in that W, T and θ are selected so that the following holds true. (2) The diffusion filter according to claim 1, wherein the light diffusion sheet is a plastic sheet in which a light diffusion material is dispersed. (3) The diffusion filter according to claim 1, which is used in a matrix display that mixes light from light sources of two or more colors.