Contrast improving sheet and rear projection screen provided with the same
First Claim
1. A contrast improving sheet to be used in combination with a display, said contrast improving sheet comprising an optical element adapted to emit image light rays substantially perpendicularly incident on an entrance surface thereof in a direction substantially perpendicular to an exit surface thereof regardless of incidence position on the entrance surface and to absorb stray light rays obliquely incident on the entrance surface and external light fallen on the exit surface.
1 Assignment
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Accused Products
Abstract
A contrast improving sheet to be disposed on the viewing side of a display, such as a rear projection display or a liquid crystal display, to display images in high contrast and in excellent directivity, and a rear projection screen provided with the contrast improving sheet are provided. A contrast improving sheet 11 includes a first optical functional element 1 and a second optical functional element 2 disposed on the viewing side of the first optical functional element 1. The first optical functional element 1 is provided with a plurality of protrusions 3 arranged in a direction or distributed in a plane. Each of the protrusions 3 has a pair of opposite total-reflection facets 5 for totally reflecting image light rays substantially perpendicularly incident on the entrance surface and a flat facet 6 extending between the front edges, on the side of the exit surface, of the pair of opposite total-reflection facets 5. Light absorbing layers 7 are formed in V-grooves between the adjacent protrusions 3. The second optical functional element 2 is provided with a light path correcting layer 9 for correcting light paths followed by the image light rays totally reflected by the total-reflection facets 5 of the protrusions 3 such that the image light rays are emitted through the exit surface substantially perpendicularly to the exit surface. The light path correcting layer 9 has a plurality of inclined planes 8 inclined in opposite directions, respectively, and the inclined planes 8 inclined in opposite directions are arranged alternately.
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Citations
12 Claims
- 1. A contrast improving sheet to be used in combination with a display, said contrast improving sheet comprising an optical element adapted to emit image light rays substantially perpendicularly incident on an entrance surface thereof in a direction substantially perpendicular to an exit surface thereof regardless of incidence position on the entrance surface and to absorb stray light rays obliquely incident on the entrance surface and external light fallen on the exit surface.
Specification