Optical: systems and elements – Projection screen – Unitary sheet comprising plural refracting areas
Reexamination Certificate
2008-01-08
2008-01-08
Lee, Diane I. (Department: 2851)
Optical: systems and elements
Projection screen
Unitary sheet comprising plural refracting areas
C359S453000, C359S460000
Reexamination Certificate
active
07317572
ABSTRACT:
There is provided a Fresnel lens sheet for converging light rays fallen thereon from oblique directions, and capable of reducing the reflection of external light, of enabling displaying images in satisfactory contrast, of suppressing the occurrence of moiré and of being easily manufactured. The Fresnel lens sheet10includes: a flat base part11;a plurality of prisms12formed on the entrance surface of the base part11,a plurality of V grooves13formed in the exit surface of the base part11,and a plurality of wedge-shaped light absorbing parts14embedded in the V grooves13,respectively. Each prism12has a refraction facet12athat refracts light rays fallen thereon and a total-reflection facet12bthat totally reflects light rays fallen thereon. The prisms12refract and reflect light rays L1incident thereon at large incident angles to deflect the light rays L1for travel in a direction substantially perpendicular to the base part11.The light absorbing parts14have a refractive index lower than that of the base part11.The inclined surfaces15a, contiguous with the base part11,of the light absorbing parts14embedded in the grooves13of the base part11reflect the light rays L1traveling through the base part11.
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Goto Masahiro
Sekiguchi Hiroshi
Cruz Magda
Dai Nippon Printing Co. Ltd.
Lee Diane I.
Oliff & Berridg,e PLC
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