JPS59119341A - Rear screen - Google Patents

Abstract

PURPOSE:To obtain a rear screen whose moire and a reflected image are prevented from being generated without spoiling its resolution by using in combination a lenticular lens and a Fresnel lens which as a specific hairline-shaped flaw on its non-lens surface. CONSTITUTION:A Fresnel lens sheet A which has a circular Fresnel lens 1 on the incidence side and hairline-shaped flaws 2 over the entire surface on the projection side horizontally (at right angles to the lenticular lens) and a lenticular lens sheet B (which may be provided with a light shielding layer 4 at the non- convergent part of the projection-side lens) which has a vertical lenticular lens 3 on the incidence side are used in combination to form the rear screen. The lenticular lens sheet B has diffusion characteristics horizontally, but, for example, a diffusing material 5 is kneaded to provide a slight vertical diffusion characteristic.

Description

[Detailed Description of the Invention] Rear screens used in TV projectors etc. are characterized by brightness and uniformity of the screen, width of horizontal observation range,
Various methods have been proposed to meet performance requirements such as low vertical optical loss, but the one with the best performance is a lens sheet consisting of two lenses: a 7-lens lens sheet and a lenticular lens sheet with black stripes. Many things are used.

However, the rear screen made of the above combination of Fresnel lens sheet and lenticular lens sheet has several drawbacks.

Among these, especially the moiré pattern that occurs due to the pitch relationship between both lens sheets and the anti-1i pattern that occurs on both surfaces of the Fresnel lens sheet.
−◆ is a big problem. As a solution to these problems, for example, a method of sandwiching a matte film, a lens sheet, and a film between the single lens sheet mentioned above has been considered. In addition, there are disadvantages such as poor adhesion between the three lens sheets (the image may be distorted or partially blurred).

It was found that the above disadvantages caused by using a matte film could be improved by making the surface of the Fresnel lens sheet matte, but if the degree of matteness was made too strong, an image would be formed on the Fresnel lens sheet. This overlaps with the image on the lenticular sheet to form a single image, which is unfavorable in terms of resolution, and it is desired to eliminate moiré and reflected images without further lowering resolution.

There are two ways to use a Fresnel lens sheet: one with the lens surface facing the light source, and one with the non-lens surface facing the light source.According to research by the present inventor, in either case, the non-lens surface Diffusion characteristics on the surface range from ±2° to 100° (//, 2
In terms of gain, when the maximum brightness on the optical axis is l, the angle range where the brightness is t / 2 or more is 1°)
- Providing a leaf S-defuser (surface diffusion layer) is effective in erasing reflected images generated on both surfaces of the Fresnel lens sheet, and with this level of diffusion layer properties, resolution is practically negligible. It was found that there was no decrease in

The present invention has been made based on the above facts, that is, the present invention combines two lens sheets, a Fresnel lens sheet and a lenticular lens sheet, and furthermore, the non-lens surface of the Fresnel lens sheet The gist of the lenticular lens sheet is a lenticular screen, which is characterized by having hairline-shaped scratches on the entire surface in a direction perpendicular to the lenticular lens.

Hereinafter, the present invention will be explained with reference to Examples and drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention, in which a Fresnel lens sheet A and a lenticular lens sheet B are combined. A hairline-shaped scratch λ is formed horizontally on the entire surface. Furthermore, a lenticular lens 3 is formed on the incident light side of the lenticular lens sheet B. A light-shielding layer 4t (usually referred to as a black stripe) may be provided on the exit side of the lenticular lens sheet B to treat the non-light-condensing part of the lenticular lens.Providing the light-shielding layer blocks stray light and blocks external light on the exit side. It has the effect of reducing reflection.

The lenticular lens sheet B has diffusion properties in the horizontal direction, but in order to further provide diffusion properties in the vertical direction, a second
Even if the diffusing material S is mixed in as shown in the figure, a diffusing material layer 6 may be provided on the output side as shown in FIG. 3, or the output part may be in a random matte state 7 as shown in FIG. q. , these may be used together. In order to provide the lenticular lens sheath) B with a diffusion characteristic in the vertical direction, it is easy to manufacture and highly efficient to provide the uniform diffusion characteristic without any directional characteristics as described above.

As mentioned in Section 2, it is preferable for the lenticular lens sheet BK to have uniform diffusion properties in terms of manufacturing, but for the Fresnel lens sheet BK, it is better to give diffusion properties only in the vertical direction. In order to improve the brightness of the resulting screen compared to the case where the Fresnel lens sheet A is provided with a 100% vertical diffusion characteristic, it is preferable to provide horizontal hairline scratches on the non-lens surface of the Fresnel lens sheet A that provide only vertical diffusion characteristics. This hairline-like scratch has a vertical diffusion characteristic (αV) of ±, 2° to ±lI0.
It is best to form it so that it is of a certain degree.

In addition, the horizontal diffusion characteristics of lenticular lens sea) B (
αH) is preferably ±330 to ±Sθ°, and the vertical diffusion characteristic (αV) is preferably ±30 to ±10°.

In order to provide the above-mentioned hairline scratches on the Fresnel lens sheet, for example, during the molding process of the Fresnel lens sheet, a transparent resin, such as This can be done by sandwiching acrylic, resin, etc. and subjecting it to hot pressure processing. Especially when considering the vertical diffusion characteristics (αV), 2° to ±4”K
To control, commercially available abrasive paper /161I00 (1100
This can be achieved by polishing the metal plate in one direction when manufacturing the above-mentioned flat metal mold using mesh) ~ /l61OθO (lθoo mesh). Alternatively, a similar mesh of abrasive grains may be sprayed in one direction.

In addition, in order to control the horizontal diffusion property (αH) of the lenticular lens sheet to ±330 to ±soo, the shape of the lenticular lens should be a circle, an ellipse, a paraboloid, etc. at the bottom of the valley of the lens. It is necessary to design so that the tangent line is between 600 and gθ0, and in order to control the vertical diffusion characteristics (aV) of the lenticular lens sheet within ±30 to ±100, the amount of the diffusing agent added and the surface light diffusing layer must be adjusted. For example, when an acrylic resin is used as the substrate, the diffusing agent has a particle size of 0. /~tio
A surface diffusion layer is provided by adding 2 to 5% μ of silica powder, alumina powder, glass powder, etc., or by pre-matting the surface of the kanaya and transferring the matte shape to the sheet to be formed during molding. method is used.

According to the present invention as described above, it is possible to regulate the diffusion characteristics not only in the horizontal direction but also in the vertical direction and provide a screen.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the lenticular lens sheet of the present invention, and FIGS. / 11111111111111@111111@Nlenel Lens Co., 11@1111...Hairline J *ee@e*s...e...Lenticular lens da......Light blocking
Layer patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Atsushi Ko Nishi Mizai 1

Claims (1)

[Claims] (11) A Fresnel lens sheet and a lenticular lens sheet are combined, and the non-lens surface of the Fresnel lens sheet has a direction perpendicular to the lenticular lens of the lenticular lens sheet. Reya screen is characterized by having hairline-like scratches on the entire surface. (2) Lenticular lens sheets have lenticular lenses on the Fresnel lens sheet side, and lenticular lenses on the opposite side of the Fresnel lens sheet. A lenticular lens sheet according to claim 1, characterized in that a light shielding layer is provided in a non-light condensing part of the lens. (3) The lenticular lens sheet has a light diffusing agent kneaded inside. Certain claims (1) or (2)
The glue screen mentioned in the section. (4) The lenticular lens sheet has a light-diffusing layer on its surface.