Dichroic prism and projection display apparatus

Inactive Publication Date: 2005-06-07
SEIKO EPSON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0009]In view of the above problems, an object of the present invention is to provide a dichroic prism that can reduce displacements of projection pixels of colors caused by chromatic aberration of magnification. Another object of the present invention is to provide a projection display apparatus in which the dichroic prism is incorporated.

Problems solved by technology

There has been a tendency to reduce the area of each pixel with this increase of definition, which lowers the permitted limit of the above-described pixel displacement d1 and decreases the tolerance for chromatic aberration of magnification.

Method used

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  • Dichroic prism and projection display apparatus
  • Dichroic prism and projection display apparatus
  • Dichroic prism and projection display apparatus

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second embodiment

[0062]FIG. 10 shows a dichroic prism having another structure to which the present invention is applied. A dichroic prism 10A of this embodiment is different from the dichroic prism 10 of the first embodiment in that the first and second rectangular prisms 11 and 12 of the four rectangular prisms 11-14 are replaced with triangular prisms 11A and 12A in each of which a vertical angle near the center of the junction of the prisms is obtuse.

[0063]In this embodiment, the first triangular prism 11A and a fourth rectangular prism 14 are joined to each other while adjusting the thickness of an adhesive layer 118 so that rectangular sides 112 and 141 provided with blue reflecting films 114 and 143 thereon form a flat plane, thereby forming a compound prism. Furthermore, the second triangular prism 12A and a rectangular prism 13 are joined to each other while adjusting the thickness of the adhesive layer 118 so that rectangular sides 121 and 132 form a flat plane, thereby forming a compound ...

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Abstract

The invention provides a dichroic prism capable of reducing displacements of projection pixels of colors caused by chromatic aberration of magnification. A dichroic prism is formed in the shape of a quadrangular prism as a whole by joining four rectangular prisms together. A red reflecting dichroic plane and a blue reflecting dichroic plane intersect to form substantially an X shape along junction surfaces of the prisms. The red reflecting dichroic plane is convex-shaped by partly changing the thickness of an adhesive layer for connecting the rectangular prisms together. Accordingly, since a red beam can be guided to a projection optical system while being enlarged, it is possible to reduce a projection image of the red beam to be projected onto a projection plane via the projection optical system. This makes it possible to reduce relative displacements of projection pixels of color beams caused by chromatic aberration of magnification.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of Invention[0002]The present invention relates to a projection display apparatus that separates light emitted from a light source into color beams of at least two colors, modulates these color beams via light valves formed of liquid crystal panels according to image information, synthesizes the modulated color beams again, and projects and displays the synthesized beams onto a projection plane via a projection optical system. More particularly, the present invention relates to a dichroic prism capable of correcting relative displacements of projection pixels of the colors caused by chromatic aberration of magnification.[0003]2. Description of Related Art[0004]A well-known type of projection display apparatus includes a light source, a color separation device that separates a light beam emitted from the light source into color beams of three colors, three light valves for modulating the separated color beams according to image information, a...

Claims

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Application Information

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IPC IPC(8): G02B27/14H04N9/07G02B5/04G02B27/12G02B27/18G02F1/13G02F1/1335G03B33/12H04N9/31
CPCG02B5/04G02B27/1026G02B27/1046G02B27/1073G02B27/145G02B27/149H04N9/3105
Inventor HASHIZUME, TOSHIAKIYAJIMA, AKITAKA
Owner SEIKO EPSON CORP
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