Projection lens and projector
AssigneeCasio Computer Co., Ltd.
InventorMakoto Sato
Life of this patent
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Abstract
There is provided a projection lens for a projector which utilizes a reflection type display device, comprising a movable aperture 70 which is movable as a movable lens components moves, wherein an opening 75 in the movable aperture 70 is formed into a circular shape which is centered at the center of an optical axis 69 of the projection lens and has a swollen portion 73 on part of the opening 75 in such a manner as to project from a circumferential portion in a direction of the center of a beam of stray light into the interior of the opening 75.
Claims15
A projection lens, which is a projection zoom lens for use in a projector utilizing a micromirror display device as a display device, the projection lens comprising a movable aperture adapted to move in an optical axis direction as a movable lens component moves,
- wherein an opening of the movable aperture is formed into a circular shape which is centered at an optical axis of the projection lens,
- wherein the movable aperture has a swollen portion formed on part of a circumferential edge of the opening in such a manner as to project into an inside of the opening in a curvilinear fashion, and
- wherein the swollen portion projects towards the opening from a circumferential edge portion which is in a direction of a center of a beam of stray light relative to a position of the optical axis of the projection lens.
A projector comprising:
- a light source unit,
- a light source side optical system,
- an illumination side optical system,
- a micromirror display device,
- a projection side optical system having a zooming function,
- a power supply circuit, and
- a projector control unit,
- wherein the projection side optical system comprises a movable aperture adapted to move in an optical axis direction as a movable lens component moves in the optical axis direction, and
- wherein the movable aperture includes a circular opening centered at a position of an optical axis of the projection side optical system, and has a swollen portion, formed on a circumferential edge portion that is in a direction of a center of a beam of stray light relative to the center of the opening, in such a manner as to project in a direction of the center of the opening.
Dependencies are inferred from the claim text.