# US 8,570,633 B2 · MEMS mirror, mirror scanner, optical scanning unit and image forming apparatus including the optical scanning unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,633 B2 - Document ID: US8570633B2 - Status: Granted - Kind: B2 - Application number: 12/511,688 - Filed: 2009-07-29 - Published: 2010-02-25 - Granted: 2013-10-29 - Earliest claimed: 2008-08-21 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Hee-Moon Jeong; Jin-Ho Lee; Jun-O Kim; Jong-Chul Choi - Inventors: Hee-Moon Jeong; Jin-Ho Lee; Jun-O Kim; Jong-Chul Choi - Web page: https://patentgrep.com/patent/US8570633B2 ## CPC - G02B 26/085: {the reflecting means being moved or deformed by electromagnetic means} - G02B 26/105: {with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence)} - H04N 1/1135: {for the main-scan only} - H04N 1/12: using the sheet-feed movement {or the medium-advance or the drum-rotation movement} as the slow scanning component, {e.g. arrangements for the main-scanning}({sheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; } using multi-element arrays H04N1/19) - H04N 2201/0082: Image hardcopy reproducer (H04N2201/0091 - H04N2201/0094 take precedence) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Disclosed are several embodiments of a micro-electro-mechanical systems (MEMS) mirror and a mirror scanner employing the same. An optical scanning unit employing such mirror scanner and an image forming apparatus including the optical scanning unit are also disclosed. The MEMS mirror may include a movable unit, which may in turn include a mirror portion and a magnet frame portion. The mirror portion may have mirror surfaces on the face surface(s) thereof. The magnet frame portion may include an opening into which a magnet is received. The MEMS mirror may also include a first fixing end and a second fixing end, to which the moving unit may be elastically supported by one or more elastic members that allows oscillating or pivoting movement of the moving unit. ## Claims ### Claim 1 A micro-electro-mechanical systems (MEMS) mirror, comprising: a movable unit including a mirror portion and a magnet frame portion, the mirror portion comprising a plurality of unit mirrors, each of which having at least two non-co-planar face surfaces each face surface including thereon one or more mirror surfaces, the magnet frame portion being configured to support therein a magnet: a first fixing end and a second fixing end spaced apart from each other and from the movable unit; and a first elastic member and a second elastic member, the first elastic member elastically supporting the movable unit to the first fixing end, the second elastic member elastically supporting the movable unit to the second fixing end, wherein the magnet frame portion comprises a face surface substantially parallel to at least one face surface of at least one unit mirror, and wherein at least one unit mirror is disposed at a first end of the face surface of the magnet frame portion and at least one unit mirror is disposed at a second end of the face surface of the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into and removed from the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into the magnet frame portion at an insertion depth at which a rotational axis of the movable unit coincides with rotating center axes of the first and second elastic members. ### Claim 2 (depends on 1) The MEMS mirror of claim 1, wherein the magnet frame portion is located between at least two adjacent ones of the plurality of unit mirrors. ### Claim 3 (depends on 1) The MEMS mirror of claim 1, wherein the mirror portion includes a first unit mirror and a second unit mirror, each of which includes one or more mirror surfaces on each of the at least two face surfaces of the mirror portion. ### Claim 4 (depends on 3) The MEMS mirror of claim 3, wherein the magnet frame portion is located between the first and second unit mirrors. ### Claim 5 (depends on 1) The MEMS mirror of claim 1, wherein the magnet frame portion is located between the mirror portion and one of the first and second elastic members. ### Claim 6 (depends on 1) The MEMS mirror of claim 1, wherein the magnet frame portion includes a first magnet frame located between the mirror portion and the first elastic member, and a second magnet frame located between the mirror portion and the second elastic member. ### Claim 7 (depends on 6) The MEMS mirror of claim 6, further comprising: a third elastic member located between the mirror portion and the first magnet frame; and a fourth elastic member located between the mirror portion and the second magnet frame. ### Claim 8 (depends on 7) The MEMS mirror of claim 7, wherein a first resonance frequency of the magnet frame portion and the first and second elastic members is greater than a second resonance frequency of the mirror portion and the third and fourth elastic members. ### Claim 9 (depends on 1) The MEMS mirror of claim 1, further comprising: a reinforcing rib formed on at least one of the at least two face surfaces of the mirror portion. ### Claim 10 (depends on 9) The MEMS mirror of claim 9, wherein the movable unit is configured to pivot about a rotational axis, the reinforcing rib extending in a direction perpendicular to the rotational axis of the movable unit. ### Claim 11 (depends on 9) The MEMS mirror of claim 9, wherein the reinforcing rib is formed on at least one of the at least two face surfaces at a location adjacent a boundary of at least one of the one or more mirror surfaces. ### Claim 12 (depends on 11) The MEMS mirror of claim 11, wherein the reinforcing rib comprises at least two reinforcing ribs each disposed on respective one of the at least two face surfaces at locations adjacent boundaries of the one or more mirror surfaces, the movable unit being configured to pivot about a rotational axis, the at least two reinforcing ribs each extending in a direction perpendicular to the rotational axis of the movable unit. ### Claim 13 (depends on 1) The MEMS mirror of claim 1, wherein the movable unit, the first and second fixing ends and the first and second elastic members are formed from a double-layered wafer including a first silicon layer and a second silicon layer. ### Claim 14 (depends on 13) The MEMS mirror of claim 13, wherein the double-layered wafer is a silicon-on-insulator (SOI) wafer. ### Claim 15 (depends on 13) The MEMS mirror of claim 13, wherein the mirror portion and the first and second elastic members are formed of the first silicon layer, the magnet frame portion and the first and second fixing ends being formed of the first and second silicon layers. ### Claim 16 (depends on 15) The MEMS mirror of claim 15, further comprising: a reinforcing rib formed of the second silicon layer on at least one of the at least two face surfaces of the mirror portion. ### Claim 17 (depends on 1) The MEMS mirror of claim 1, wherein the magnet frame portion includes an opening in which to receive the magnet, the movable unit being configured to pivot about a rotational axis, an insertion depth of the magnet being determined such that the rotational axis of the movable unit coincides with rotating center axes of the first and second elastic members. ### Claim 18 (depends on 1) The MEMS mirror of claim 1, wherein the first and second elastic members are formed in zigzag shapes. ### Claim 19 A mirror scanner, comprising: a micro-electro-mechanical systems (MEMS) mirror including: a movable unit including a mirror portion and a magnet frame portion, the mirror portion comprising a plurality of unit mirrors, each of which having at least two non-co-planar face surfaces each face surface including thereon one or more mirror surfaces, the magnet frame portion being coupled to the mirror portion, the magnet frame, portion supporting therein a permanent magnet; a first fixing end and a second fixing end spaced apart from each other and from the movable unit; and a first elastic member and a second elastic member, the first elastic member elastically supporting the movable unit to the first fixing end, the second elastic member elastically supporting the movable unit to the second fixing end; and an electromagnet portion including a yoke and a coil surrounding the yoke, the yoke having end portions spaced apart from, and facing, each other, the end portions being arranged adjacent the permanent magnet to thereby provide an electromagnetic driving force to the MEMS mirror, wherein the magnet frame portion comprises a face surface substantially parallel to at least one face surface of at least one unit mirror, and wherein at least one unit mirror is disposed at a first end of the face surface of the magnet frame portion and at least one unit mirror is disposed at a second end of the face surface of the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into and removed from the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into the magnet frame portion at an insertion depth at which a rotational axis of the movable unit coincides with rotating center axes of the first and second elastic members. ### Claim 20 (depends on 19) The mirror scanner of claim 19, wherein a magnetic pole direction of the permanent magnet is perpendicular to the mirror surface, the end portions of the yoke facing one of magnetic poles of the permanent magnet. ### Claim 21 (depends on 19) The mirror scanner of claim 19, wherein the magnetic pole direction of the permanent magnet is parallel to the one or more mirror surfaces and perpendicular to a rotational axis about which the movable unit rotates, the end portions of the yoke facing one of magnetic poles of the permanent magnet. ### Claim 22 (depends on 19) The mirror scanner of claim 19, wherein the mirror portion includes a first unit mirror and a second unit mirror, each of which includes one or more mirror surfaces on both of two face surfaces of the mirror portion. ### Claim 23 (depends on 22) The mirror scanner of claim 22, wherein the magnet frame portion is located between the first and second unit mirrors. ### Claim 24 (depends on 23) The mirror scanner of claim 23, wherein a thickness of the electromagnet portion along a direction parallel to the one or more mirror surface is less than a distance between the first and second unit mirrors. ### Claim 25 (depends on 23) The mirror scanner of claim 23, wherein the electromagnet portion is disposed at a space between a first light beam reflected off the first unit mirror and a second light beam reflected off the second unit mirror. ### Claim 26 (depends on 19) The mirror scanner of claim 19, wherein the magnet frame portion is located between the mirror portion and one of the first and second elastic members. ### Claim 27 (depends on 26) The mirror scanner of claim 26, wherein the electromagnet portion is positioned away from optical paths of light beams that are incident on the mirror portion, the yoke extending from the end portions to the coil at an incline. ### Claim 28 (depends on 19) The mirror scanner of claim 19, wherein the magnet frame portion includes a first magnet frame that is located between the mirror portion and the first elastic member and a second magnet frame that is located between the mirror portion and the second elastic member, the electromagnet portion including a first electromagnet corresponding to the first magnet frame and a second electromagnet corresponding to the second magnet frame. ### Claim 29 (depends on 28) The mirror scanner of claim 28, further comprising: a third elastic member and a fourth elastic member, the third elastic member being located between the mirror portion and the first magnet frame, the fourth elastic member being located between the mirror portion and the second magnet frame. ### Claim 30 (depends on 29) The mirror scanner of claim 29, wherein a first resonance frequency of the magnet frame portion, the first elastic member and the second elastic member is greater than a second resonance frequency of the mirror portion, third elastic member and the fourth elastic member, and wherein the electromagnet portion drives the magnet frame portion at the second resonance frequency. ### Claim 31 (depends on 19) The mirror scanner of claim 19, further comprising: a reinforcing rib formed on at least one of surfaces of the mirror portion. ### Claim 32 An optical scanning unit, comprising: a plurality of light sources; and a mirror scanner configured to receive a plurality of light beams from the plurality of light sources, and to deflect the received plurality of light beams toward one or more surfaces to be scanned, wherein the mirror scanner includes: a micro-electro-mechanical systems (MEMS) mirror that comprises: a movable unit including a mirror portion and a magnet frame portion, the mirror portion comprising a plurality of unit mirrors, each of which having at least two non-co-planar face surfaces each face surface including thereon one or more mirror surfaces, a magnet frame portion being coupled to the mirror portion, the magnet frame portion supporting therein a permanent magnet; a first fixing end and a second fixing end spaced apart from each other and from the movable unit; and a first elastic member and a second elastic member, the first elastic member elastically supporting the movable unit to the first fixing end, the second elastic member elastically supporting the movable unit to the second fixing end; and an electromagnet portion including a yoke and a coil surrounding the yoke, the yoke having end portions spaced apart from, and facing, each other, the end portions being arranged adjacent the permanent magnet to thereby provide an electromagnetic driving force to the MEMS mirror, wherein the magnet frame portion comprises a face surface substantially parallel to at least one face surface of at least one unit mirror, and wherein at least one unit mirror is disposed at a first end of the face surface of the magnet frame portion and at least one unit mirror is disposed at a second end of the face surface of the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into and removed from the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into the magnet frame portion at an insertion depth at which a rotational axis of the movable unit coincides with rotating center axes of the first and second elastic members. ### Claim 33 (depends on 32) The optical scanning unit of claim 32, farther comprising: a focusing optics configured to focus the plurality of defected light beams deflected by the mirror scanner onto the one or more surfaces to be scanned. ### Claim 34 (depends on 33) The optical scanning unit of claim 33, wherein the focusing optics comprises a arcsinusoidal compensation lens that applies an arcsinusoidal function to the plurality of deflected light beams so that the light beams deflected by the mirror scanner are scanned at a uniform velocity. ### Claim 35 (depends on 32) The optical scanning unit of claim 32, wherein the mirror portion includes a first unit mirror and a second unit mirror, each of which including a mirror surface on each of two faces of the mirror portion. ### Claim 36 (depends on 35) The optical scanning unit of claim 35, wherein at least two of the plurality of light beams, which are incident upon a first mirror surface corresponding to at least one of the first and second unit mirrors, are parallel to each other. ### Claim 37 (depends on 32) The optical scanning unit of claim 32, wherein at least one of the plurality of light beams incident upon the mirror surface on one of the two faces of the unit mirror has an oblique incident angle. ### Claim 38 An image forming apparatus, comprising: a plurality of photosensitive media; an optical scanning unit including a plurality of light sources and a mirror scanner, the mirror scanner receiving a plurality of light beams from the plurality of light sources, and deflecting each of the received plurality of light beams toward the corresponding respective one of plurality of photosensitive media to thereby form electrostatic latent images on the plurality of photosensitive media: and a developing unit configured to supply toner to develop the electrostatic latent images formed on the photosensitive media, wherein the mirror scanner comprises: a micro-electro-mechanical systems (MEMS) mirror that comprises: a movable unit including a mirror portion and a magnet frame portion, the mirror portion comprising a plurality of unit mirrors, each of which having at least two non-co-planar face surfaces each face surface including thereon one or more mirror surfaces, a magnet frame portion being coupled to the mirror portion, the magnet frame portion supporting therein a permanent magnet; a first fixing end and a second fixing end spaced apart from each other and from the movable unit; and a first elastic member and a second elastic member, the first elastic member elastically supporting the movable unit to the first fixing end, the second elastic member elastically supporting the movable unit to the second fixing end; and an electromagnet portion including a yoke and a coil surrounding the yoke, the yoke having end portions spaced apart from, and facing, each other, the end portions being arranged adjacent the permanent magnet to thereby provide an electromagnetic driving force to the MEMS mirror, wherein the magnet frame portion comprises a face surface substantially parallel to at least one face surface of at least one unit mirror, and wherein at least one unit mirror is disposed at a first end of the face surface of the magnet frame portion and at least one unit mirror is disposed at a second end of the face surface of the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into and removed from the magnet frame portion, and wherein the magnet frame portion includes a grip structure extending into the opening for supporting the magnet in place such that the magnet may be inserted into the magnet frame portion at an insertion depth at which a rotational axis of the movable unit coincides with rotating center axes of the first and second elastic members. ### Claim 39 (depends on 38) The image forming apparatus of claim 38, wherein the mirror portion includes a first unit mirror and a second unit mirror, each of which includes one or more mirror surfaces on each of two face surfaces of the mirror portion, at least two of the plurality of light beams incident upon one of the one or more mirror surfaces being parallel to each other. ### Claim 40 (depends on 38) The image forming apparatus of claim 38, wherein at least one of the plurality of light beams incident upon the mirror surface on one of the two faces of at least one unit mirror having an oblique incident angle.