# US 2017/0285361 A1 · Stage apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285361 A1 - Document ID: US20170285361A1 - Status: Published application - Kind: A1 - Application number: 15/435,352 - Filed: 2017-02-17 - Published: 2017-10-05 - Earliest claimed: 2016-03-29 - Assignees: Ricoh Imaging Company, Ltd. - Applicants: Ricoh Imaging Company, Ltd. - Inventors: Eiichi ITO - Web page: https://patentgrep.com/patent/US20170285361A1 ## CPC - G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)} - G02B 7/04: with mechanism for focusing or varying magnification - G02B 7/28: Systems for automatic generation of focusing signals - H02K 41/02: Linear motors; Sectional motors - H02K 2201/18: Machines moving with multiple degrees of freedom - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A stage apparatus includes a movable member configured to move in a direction parallel to a predetermined plane, a base member configured to support the movable member to move relative to the base member, and a thrust generator including: a magnet provided on one the movable member and the base member, and a coil provided on the other of the movable member and the base member. The magnet and the coil generating a thrust to move the movable member in a direction parallel to the predetermined plane. A magnetic flux density of the magnet toward the coil changes along the thrust direction. ## Claims ### Claim 1 A stage apparatus comprising: a movable member configured to move in a direction parallel to a predetermined plane; a base member configured to support said movable member to move relative to said base member; and a thrust generator including: a magnet provided on one of said movable member and said base member, and a coil provided on the other of said movable member and said base member, said magnet and said coil generating a thrust to move said movable member in a direction parallel to said predetermined plane, wherein a magnetic flux density of said magnet toward said coil changes along the thrust direction. ### Claim 2 (depends on 1) The stage apparatus according to claim 1, wherein said movable member and said base member are each single members, wherein said magnet is provided on one of said movable member and said base member, and wherein said coil is provided on the other of said movable member and said base member at a position facing said magnet. ### Claim 3 (depends on 1) The stage apparatus according to claim 1, wherein a pair of said base members are provided which face each other, at either side of said movable member, in a direction that is orthogonal to said predetermined plane, wherein said magnets are respectively provided on said pair of said base members at positions, at either side of said movable member, so that said magnets face each other, and wherein said coil is provided on said movable member in between said magnets that face each other. ### Claim 4 (depends on 2) The stage apparatus according to claim 2, wherein said magnet has a recessed cross-sectional shape so that a thickness thereof in a direction that is orthogonal to said predetermined plane is relatively thick at either end of said magnet, with respect to said thrust direction, and a thickness thereof in the direction that is orthogonal to said predetermined plane is relatively thin at a central portion of said magnet, with respect to said thrust direction. ### Claim 5 (depends on 4) The stage apparatus according to claim 4, wherein a depth of a recess of said recessed cross-sectional shape of said magnet is ⅗ through ⅘ of the overall thickness of said magnet in said direction that is orthogonal to said predetermined plane. ### Claim 6 (depends on 2) The stage apparatus according to claim 2, wherein a magnetic flux density ratio at the central portion of said magnet is 15% through 30% less than that at either end of said magnet with respect to the thrust direction. ### Claim 7 (depends on 2) The stage apparatus according to claim 2, wherein a magnetizing force ratio at the central portion of said magnet is 15% through 30% less than that at either end of said magnet with respect to the thrust direction. ### Claim 8 (depends on 3) The stage apparatus according to claim 3, wherein each of said magnets has a recessed cross-sectional shape so that a thickness thereof in a direction that is orthogonal to said predetermined plane is relatively thick at either end of said magnet, with respect to said thrust direction, and a thickness thereof in the direction that is orthogonal to said predetermined plane is relatively thin at a central portion of said magnet, with respect to said thrust direction, wherein a depth of a recess of said recessed cross-sectional shape of said magnet is ¼ through ½ of the overall thickness of said magnet in said direction that is orthogonal to said predetermined plane. ### Claim 9 (depends on 3) The stage apparatus according to claim 3, wherein a magnetic flux density ratio at the central portion of said magnet is 20% through 50% less than that at either end of said magnet with respect to the thrust direction. ### Claim 10 (depends on 3) The stage apparatus according to claim 3, wherein a magnetizing force ratio at the central portion of said magnet is 20% through 50% less than that at either end of said magnet with respect to the thrust direction. ### Claim 11 (depends on 1) The stage apparatus according to claim 1, wherein a magnetizing force of said magnet is distributed in a concave form so that the magnetizing force is higher at either end of said magnet than the central portion of said magnet, with respect to the thrust direction. ### Claim 12 (depends on 1) The stage apparatus according to claim 1, wherein a magnetizing force of said magnet is distributed in a substantial trapezoidal form so that the magnetizing force is higher at either end of said magnet than the central portion of said magnet, with respect to the thrust direction. ### Claim 13 (depends on 1) The stage apparatus according to claim 1, wherein a magnetizing force of said magnet is distributed in a substantial rectangular form so that the magnetizing force is higher at either end of said magnet than the central portion of said magnet, with respect to the thrust direction. ### Claim 14 (depends on 1) The stage apparatus according to claim 1, wherein said magnet comprises: a non-magnetic material in a central portion thereof, with respect to the trust direction; and a pair of magnets on either side of said non-magnetic material. ### Claim 15 (depends on 1) The stage apparatus according to claim 1, wherein an image sensor is provided on said movable member. ### Claim 16 (depends on 1) The stage apparatus according to claim 1, wherein an optical member is provided on said movable member, said optical member constituting part of a photographing optical system. ### Claim 17 (depends on 1) A photographing apparatus provided with the stage apparatus according to claim 1, wherein an image sensor is provided on said movable member of said stage apparatus. ### Claim 18 (depends on 1) An optical instrument provided with the stage apparatus according to claim 1, wherein an optical member is provided on said movable member of said stage apparatus, said optical member constituting part of a photographing optical system. ### Claim 19 A stage apparatus for an image projector apparatus, comprising: a movable member configured to move in a direction parallel to a predetermined plane, said movable member provided with one of an image-forming element which forms an image and a projector optical system that is configured to project an image formed by an image-forming element; a base member configured to support said movable member to move relative to said base member; and a thrust generator including: a magnet provided on one said movable member and said base member, and a coil provided on the other of said movable member and said base member, said magnet and said coil generating a thrust to move said movable member in a direction parallel to said predetermined plane, wherein a magnetic flux density of said magnet toward said coil changes along the thrust direction.