Transmission type projector screen utilizing parallel optical sheets and prism lenses
First Claim
1. A transmission type projection screen comprising:
- a plurality of parallel optical sheets arranged perpendicularly to an optical axis, said optical sheets including a front sheet having a front surface exposed directly to an observation side and a rearmost sheet having a surface facing a light source which emits light that passes substantially along said optical axis through said rearmost sheet and then through said front sheet to said observation side, said front sheet having a rear surface opposite to said front surface; and
a plurality of prism lenses formed on said rear surface of said front sheet and including unit triangular prisms extending in a first direction along said rear surface and disposed in a succeeding arrangement, wherein each of the unit triangular prisms has a first inclined surface and a second inclined surface, and wherein the angle between said second inclined surface and said rear surface is less than the angle between said first inclined surface and said rear surface, said first inclined surface being so inclined as to internally reflect an outside light coming from the observation side into each unit triangular prism, to a direction inclined to said optical axis to remove said outside light out of viewer'"'"'s sight.
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Accused Products
Abstract
A transmission type projection screen comprises a plurality of sheets. The front sheet nearest to the front observation side is an ambient light attenuating front sheet which is provided on its surface facing the rear side with first prism lenses formed by successively and horizontally arranging unit triangular prisms. Each unit triangular prism has a sharply inclined surface inclined at an angle of about 90° to the surface of the front sheet, and a gently inclined surface inclined at an angle in the range of 5° to 40° to the surface of the front sheet. The first prism lenses are disposed with the gently inclined surfaces of the unit triangular prisms thereof facing upward. Second prism lenses may be provided on its surface facing the front observation side, each of the second prism lenses also having a sharply inclined surface and a gently inclined surface.
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Citations
13 Claims
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1. A transmission type projection screen comprising:
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a plurality of parallel optical sheets arranged perpendicularly to an optical axis, said optical sheets including a front sheet having a front surface exposed directly to an observation side and a rearmost sheet having a surface facing a light source which emits light that passes substantially along said optical axis through said rearmost sheet and then through said front sheet to said observation side, said front sheet having a rear surface opposite to said front surface; and a plurality of prism lenses formed on said rear surface of said front sheet and including unit triangular prisms extending in a first direction along said rear surface and disposed in a succeeding arrangement, wherein each of the unit triangular prisms has a first inclined surface and a second inclined surface, and wherein the angle between said second inclined surface and said rear surface is less than the angle between said first inclined surface and said rear surface, said first inclined surface being so inclined as to internally reflect an outside light coming from the observation side into each unit triangular prism, to a direction inclined to said optical axis to remove said outside light out of viewer'"'"'s sight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification