Projection type image display apparatus
View Patent ↗According to the present invention, a projection type image display apparatus enables control of a large amount of light masking through a light-masking unit while maintaining a uniform illumination distribution in an area to be illuminated by the illumination light. The apparatus uses two array lenses on which lens cells are arranged in matrix form, where light-masking unit masks the array lens installed on the light source side in their particular area. The light-masking unit adjusts the amount of light emitted from the light source. The light-masking area of lens cells adjacent to lens cells closest to an optical axis is made smaller than the light-masking area of other cells.
1. A projection type image display apparatus, comprising;
a light source which emits light;
an optical system which includes a first array lens and a second array lens and a superimposing lens;
a light valve which receives light passed through said optical system;
a projection lens which projects the light from said light valve; and
a light-masking unit to adjust a light masking amount by masking light beams between said first array lens and said second array lens,
wherein:
said first array lens has a plurality of lens cells arranged in a first direction and a second direction, including:
1) at least one center lens cell contacting an optical axis of the light emitted from said light source,
2) at least one first adjacent lens cell adjacent to said at least one center lens cell in said first direction away from said optical axis, and
3) at least one second adjacent lens cell adjacent to said at least one center lens cell in said second direction away from said optical axis,
in one light-masking condition, said light-masking unit masks light beams between said first array lens and said second array lens so that not less than 80% of the amount of light which is emitted from said light source and reaches said light valve is masked; both a light beam through said at least one center lens cell and a light beam through said at least one first adjacent lens cell are partially light-masked; a light beam through said at least one second adjacent lens cell is entirely light-masked; and a light masking amount of said light beam through said at least one first adjacent lens cell is less than one half of an amount of light beam through said at least one first adjacent lens cell.
2. The projection type image display apparatus as defined in claim 1 , wherein
said light-masking unit turns or moves a plurality of light masks to adjust a light masking amount in the direction parallel to said second direction.
3. The projection type image display apparatus as defined in claim 1 , wherein
in said light-masking condition, a light-masking area for said at least one first adjacent lens cell is smaller than a light-masking area for said at least one center lens cell.
4. A projection type image display apparatus, comprising:
a light source which emits light;
a first array lens and a second array lens which have a plurality of lens cells arranged in a first direction and a second direction;
a light valve which receives light passed through said first array lens and second array lens;
a projection lens which projects the light from said light valve; and
a light-masking unit to adjust a light masking amount by masking light beams between said first array lens and said second array lens,
wherein:
one of said two array lenses has:
1) at least one center lens cell positioned at the center of said plurality of lens cells,
2) at least one first adjacent lens cell adjacent to said at least one center lens cell in said first direction away from the center of said plurality of lens cells, and
3) at least one second adjacent lens cell adjacent to said at least one center lens cell in said second direction away from the center of said plurality of lens cells,
in one light-masking condition, said light-masking unit masks light beams between said first array lens and said second array lens so that not less than 80% of the amount of light which is emitted from said light source and reaches said light valve is masked; both a light beam through said at least one center lens cell and a light beam through said at least one first adjacent lens cell are partially light-masked; a light beam through said at least one second adjacent lens cell is entirely light-masked; and a light masking amount of said light beam through said at least one first adjacent lens cell is less than one half of an amount of light beam through said at least one first adjacent lens cell.
5. The projection type image display apparatus as defined in claim 4 , wherein
said light-masking unit changes a light masking area for said light beams in the direction parallel to said second direction by turning or moving a plurality of light masks.
6. The projection type image display apparatus as defined in claim 5 , wherein
in said light-masking condition, a light-masking area for said at least one first adjacent lens cell is smaller than a light-masking area for said at least one center lens cell.