Optical: systems and elements – Single channel simultaneously to or from plural channels – By surface composed of lenticular elements
Patent
1999-05-17
2000-11-07
Epps, Georgia
Optical: systems and elements
Single channel simultaneously to or from plural channels
By surface composed of lenticular elements
620455, G02B 2710, G03B 2160
Patent
active
061444960
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lenticular lens sheet used for televisions of rear projection type, a manufacturing method of the lenticular lens sheet and a transmission screen.
2. Description of the related art
There are two types of lenticular lens sheets. One type is a two-side lenticular lens sheet, and the other type is a one-side lenticular lens sheet.
The two-side lenticular lens sheet comprises: an incident side lenticular lens provided on the incident side into which the light comes, for diffusing the light in the horizontal direction; and an output side lenticular lens provided on the output side out of which the light is emitted, for calibrating the optical axis. The light absorbing layers (black stripes) are formed on the surface of the output side, at non-output portions (non-transmissive portions) for the light condensed by the incident side lenticular lenses, for enhancing the contrast. In the case of using the two-side lenticular lens sheet, diffusion of the light in the vertical direction is controlled by mixing a diffusing material into the sheet, or by providing lenticular lenses of vertical diffusion type on the incident side of the Fresnel lens arranged on the incident side (light source side) with respect to the two-side lenticular sheet.
On the other hand, contrast of the one-side lenticular lens sheet is enhanced by coloring the sheet.
However, the two-side lenticular lens sheet has a difficulty in achieving a fine lens pitch for the following reasons.
First, the thickness of the sheet becomes thinner if the lens pitch is made smaller, because the output portion has to be provided near the focuses of the incident side lenticular lenses in order to increase the area of the light absorbing layer.
Second, it is difficult to position the incident side lenticular lenses and the output side lenticular lenses to coincide with each other.
Third, the reproduction of the lens shape is not good with the extrusion method.
Furthermore, the two-side lenticular lens sheet tends to be damaged while it is transported or used, because its output side has a minute shape.
On the other hand, it is difficult to sufficiently enhance the contrast of the one-side lenticular lens sheet, even if the sheet is colored.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a lenticular lens sheet that can achieve fine lens pitch and enhanced contrast, a manufacturing method for the lenticular lens sheet and a transmission screen.
To achieve the above object, this invention provides a lenticular lens sheet comprising; a lenticular lens portion having a plurality of lenticular lenses on an incident side of the sheet, wherein a top portion of each of the lenticular lenses has a slit-shaped light absorbing portion formed in a longitudinal direction of the lenticular lens.
Preferably, the depth of the light absorbing portion is 0.1 to 1.5 times as great as the height of the lens of the lenticular lens portion, and the maximum width of the light absorbing portion is 3 .mu.m to 100 .mu.m. Preferably, the light absorbing portion is formed of an black ink. In addition, a flat portion is preferably formed between two neighboring lenticular lenses in order to make up with a quantity of light absorbed by the light absorbing portion.
Preferably, the surface of the output side of the sheet is substantially planar. Furthermore, the lenticular lens is formed in such a manner that a surface portion of the lens forms an angle not less than 40 degrees with a major plane of a screen. The surface of the output side of the sheet is preferably provided with a surface-coating layer which includes at least one of a hard-coating layer, a reflection-preventing-coating layer, a polarizing-film layer and a rewritable-coating layer.
The lenticular lens portion is preferably made of an ionizing radiation curable resin, such as an ultraviolet ray curable resin or an electron beam curable resin.
Another feature of this invention is that the lenticular lens sheet com
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Microfilm of the specification and drawings annexed to the request of Japanese Utility Model Application No. 39963/1981 (Laid Open No. 153334/1981) (Sony Corp), Sep. 27, 1982 pp. 5 to 9.
Dai Nippon Printing Co. Ltd.
Epps Georgia
Seyrafi Saeed
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