# US 7,607,785 B2 · Projection lens and projector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,785 B2 - Document ID: US7607785B2 - Status: Granted - Kind: B2 - Application number: 11/809,861 - Filed: 2007-06-01 - Published: 2007-12-06 - Granted: 2009-10-27 - Earliest claimed: 2006-06-05 - Assignees: Casio Computer Co., Ltd. - Inventors: Makoto Sato - Web page: https://patentgrep.com/patent/US7607785B2 ## CPC - H04N 9/3114: {by using a sequential colour filter producing one colour at a time} - G02B 13/16: for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV} - G03B 21/005: {Projectors using an electronic spatial light modulator but not peculiar thereto} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The projection lens as set forth in claim 1, wherein the movable aperture is disposed in an airspace between a first lens component and a second lens component such that a distance between a first lens element lying ahead of and a second lens element lying behind the movable aperture is changeable. ### Claim 3 (depends on 1) The projection lens as set forth in claim 1, wherein the movable aperture is fixed to an aperture supporting barrel which is supported via an elastic material on a movable lens barrel in which a given movable lens component is fixed. ### Claim 4 (depends on 1) The projection lens as set forth in claim 1, wherein the movable aperture is fixed to a supporting barrel which is independent from a movable lens barrel in which a given movable lens component is fixed. ### Claim 5 (depends on 1) The projection lens as set forth in claim 1, wherein the swollen portion projects into the inside of the circular opening in an arc-like shape. ### Claim 6 (depends on 5) The projection lens as set forth in claim 5, wherein a center of curvature of the arc-like shape is a position of the center of the beam of stray light. ### Claim 7 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. ### Claim 8 (depends on 7) The projector as set forth in claim 7, wherein the movable aperture is disposed in an airspace between a first lens component and a second lens component such that a distance between a first lens element lying ahead of and a second lens element lying behind the movable aperture is changeable. ### Claim 9 (depends on 7) The projector as set forth in claim 7, wherein the movable aperture is fixed to an aperture supporting barrel which is supported via an elastic material on a movable lens barrel in which a given movable lens component is fixed. ### Claim 10 (depends on 7) The projector as set forth in claim 7, wherein the movable aperture is fixed to a supporting barrel which is independent from a movable lens barrel in which a given movable lens component is fixed. ### Claim 11 (depends on 7) The projector as set forth in claim 7, wherein a DMD is used as the micromirror display device, and wherein the swollen portion projects from the circumferential edge portion towards the opening in an arc-like shape. ### Claim 12 (depends on 2) The projection lens as set forth in claim 2, wherein the movable aperture is fixed to an aperture supporting barrel which is supported via an elastic material on a movable lens barrel in which a given movable lens component is fixed. ### Claim 13 (depends on 2) The projection lens as set forth in claim 2, wherein the movable aperture is fixed to a supporting barrel which is independent from a movable lens barrel in which a given movable lens component is fixed. ### Claim 14 (depends on 8) The projector as set forth in claim 8, wherein the movable aperture is fixed to an aperture supporting barrel which is supported via an elastic material on a movable lens barrel in which a given movable lens component is fixed. ### Claim 15 (depends on 8) The projector as set forth in claim 8, wherein the movable aperture is fixed to a supporting barrel which is independent from a movable lens barrel in which a given movable lens component is fixed.