Projection type image display apparatus with light masking
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 polarization conversion element;
a light valve which receives light passed through the optical system;
a projection lens which projects the light from the light valve; and
a light-masking unit which has only two light-masking plates to be turned or moved so as to adjust a light masking amount by masking light beams between the first array lens and the second array lens,
wherein:
the 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 the light source,
2) at least one first adjacent lens cell adjacent to the at least one center lens cell in the first direction away from the optical axis, and
3) at least one second adjacent lens cell adjacent to the at least one center lens cell in the second direction away from the optical axis,
in one light-masking condition, the light-masking unit masks light beams between the first array lens and the second array lens so that not less than 80% of the amount of light which is emitted from the light source and reaches the light valve is masked by the two light-masking plates; each of the at least one center lens cell, the at least one first adjacent lens cell, and one lens cell or more lens cells arranged in the first direction from the at least one first adjacent lens cell is partially light-masked and partially open; the at least one second adjacent lens cell is entirely light-masked; and a light masking ratio of the at least one center lens cell is different from a light masking ratio of the at least one first adjacent lens cell.
2. The projection type image display apparatus as defined in claim 1 , wherein each of one lens cell or more lens cells arranged in the second direction from the at least one second adjacent lens cell is entirely light-masked.
3. The projection type image display apparatus as defined in claim 1 , wherein the light-masking unit turns or moves the two light-masking plates to adjust a light masking amount in the direction parallel to the second direction.
4. The projection type image display apparatus as defined in claim 1 , wherein the amount of light masked by the light-masking unit increases when the two light-masking plates are turned or moved close to each other by the light-masking unit.
5. The projection type image display apparatus as defined in claim 1 , wherein each of the two light-masking plates includes a flat surface to mask the light beams.
6. The projection type image display apparatus as defined in claim 1 , wherein each of the two light-masking plates has a partially straight-line edge.
7. The projection type image display apparatus as defined in claim 1 , wherein the optical system includes a superimposing lens.
8. The projection type image display apparatus as defined in claim 1 , wherein in the light-masking condition, a light-masking area for the at least one first adjacent lens cell is smaller than a light-masking area for the at least one center lens cell.
9. 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 polarization conversion element;
a light valve which receives light passed through the optical system;
a projection lens which projects the light from the light valve; and
a light-masking unit which has only two light-masking plates to be turned or moved so as to adjust a light masking amount by masking light beams between the first array lens and the second array lens,
wherein:
the 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 the light source,
2) at least one first adjacent lens cell adjacent to the at least one center lens cell in the first direction away from the optical axis, and
3) at least one second adjacent lens cell adjacent to the at least one center lens cell in the second direction away from the optical axis,
in one light-masking condition, the light-masking unit masks light beams between the first array lens and the second array lens so that not less than 80% of the amount of light which is emitted from the light source and reaches the light valve is masked by the two light-masking plates; each of the at least one center lens cell, the at least one first adjacent lens cell, and one lens cell or more lens cells arranged in the first direction from the at least one first adjacent lens cell is partially light-masked and partially open; the at least one second adjacent lens cell is entirely light-masked; and a shape of a light masking area for the at least one center lens cell is different from a shape of a light masking area for the at least one first adjacent lens cell.
10. The projection type image display apparatus as defined in claim 9 , wherein each of one lens cell or more lens cells arranged in the second direction from the at least one second adjacent lens cell is entirely light-masked.
11. The projection type image display apparatus as defined in claim 9 , wherein the light-masking unit turns or moves the two light-masking plates to adjust a light masking amount in the direction parallel to the second direction.
12. The projection type image display apparatus as defined in claim 9 , wherein the amount of light masked by the light-masking unit increases when the two light-masking plates are turned or moved close to each other by the light-masking unit.
13. The projection type image display apparatus as defined in claim 9 , wherein each of the two light-masking plates includes a flat surface to mask the light beams.
14. The projection type image display apparatus as defined in claim 9 , wherein each of the two light-masking plates has a partially straight-line edge.
15. The projection type image display apparatus as defined in claim 9 , wherein the optical system includes a superimposing lens.
16. The projection type image display apparatus as defined in claim 9 , wherein in the light-masking condition, a light-masking area for the at least one first adjacent lens cell is smaller than a light-masking area for the at least one center lens cell.
17. 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 polarization conversion element;
a light valve which receives light passed through the optical system;
a projection lens which projects the light from the light valve; and
a light-masking unit which has only two light-masking plates to be turned or moved so as to adjust a light masking amount by masking light beams between the first array lens and the second array lens, wherein each of the two light-masking plates includes a flat surface to mask the light beams,
wherein:
the 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 the light source,
2) at least one first adjacent lens cell adjacent to the at least one center lens cell in the first direction away from the optical axis, and
3) at least one second adjacent lens cell adjacent to the at least one center lens cell in the second direction away from the optical axis,
in one light-masking condition, the light-masking unit masks light beams between the first array lens and the second array lens so that not less than 80% of the amount of light which is emitted from the light source and reaches the light valve is masked by the two light-masking plates; both the at least one center lens cell and the at least one first adjacent lens cell are partially light-masked and partially open; the at least one second adjacent lens cell is entirely light-masked; and a light masking ratio of the at least one center lens cell is different from a light masking ratio of the at least one first adjacent lens cell.
18. The projection type image display apparatus as defined in claim 17 , wherein each of one lens cell or more lens cells arranged in the second direction from the at least one second adjacent lens cell is entirely light-masked.
19. The projection type image display apparatus as defined in claim 17 , wherein the light-masking unit turns or moves the two light-masking plates to adjust a light masking amount in the direction parallel to the second direction.
20. The projection type image display apparatus as defined in claim 17 , wherein the amount of light masked by the light-masking unit increases when the two light-masking plates are turned or moved close to each other by the light-masking unit.
21. The projection type image display apparatus as defined in claim 17 , wherein each of the two light-masking plates has a partially straight-line edge.
22. The projection type image display apparatus as defined in claim 17 , wherein the optical system includes a superimposing lens.
23. The projection type image display apparatus as defined in claim 17 , wherein in the light-masking condition, a light-masking area for the at least one first adjacent lens cell is smaller than a light-masking area for the at least one center lens cell.
24. 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 polarization conversion element;
a light valve which receives light passed through the optical system;
a projection lens which projects the light from the light valve; and
a light-masking unit which has only two light-masking plates to be turned or moved so as to adjust a light masking amount by masking light beams between the first array lens and the second array lens, wherein each of the two light-masking plates includes a flat surface to mask the light beams,
wherein:
the 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 the light source,
2) at least one first adjacent lens cell adjacent to the at least one center lens cell in the first direction away from the optical axis, and
3) at least one second adjacent lens cell adjacent to the at least one center lens cell in the second direction away from the optical axis,
in one light-masking condition, the light-masking unit masks light beams between the first array lens and the second array lens so that not less than 80% of the amount of light which is emitted from the light source and reaches the light valve is masked by the two light-masking plates; both the at least one center lens cell and the at least one first adjacent lens cell are partially light-masked and partially open; the at least one second adjacent lens cell is entirely light-masked; and a shape of a light masking area for the at least one center lens cell is different from a shape of a light masking area for the at least one first adjacent lens cell.
25. The projection type image display apparatus as defined in claim 24 , wherein each of one lens cell or more lens cells arranged in the second direction from the at least one second adjacent lens cell is entirely light-masked.
26. The projection type image display apparatus as defined in claim 24 , wherein the light-masking unit turns or moves the two light-masking plates to adjust a light masking amount in the direction parallel to the second direction.
27. The projection type image display apparatus as defined in claim 24 , wherein the amount of light masked by the light-masking unit increases when the two light-masking plates are turned or moved close to each other by the light-masking unit.
28. The projection type image display apparatus as defined in claim 24 , wherein each of the two light-masking plates has a partially straight-line edge.
29. The projection type image display apparatus as defined in claim 24 , wherein the optical system includes a superimposing lens.
30. The projection type image display apparatus as defined in claim 24 , wherein in the light-masking condition, a light-masking area for the at least one first adjacent lens cell is smaller than a light-masking area for the at least one center lens cell.