# US 2004/0001263 A1 · MEMS structure with mechanical overdeflection limiter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2004/0001263 A1 - Document ID: US20040001263A1 - Status: Published application - Kind: A1 - Application number: 10/625,883 - Filed: 2003-07-22 - Published: 2004-01-01 - Earliest claimed: 2002-06-28 - Assignees: Glimmerglass Networks, Inc. - Inventors: Bryan P. Staker; James P. Spallas; Lawrence P. Muray; Andres Femandez - Web page: https://patentgrep.com/patent/US20040001263A1 ## CPC - B81B 3/0051: {For defining the movement, i.e. structures that guide or limit the movement of an element (mechanical arrangements for preventing or damping vibration or shock H01H3/60)} - G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means} - B81B 2201/042: Micromirrors, not used as optical switches - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A MEMS device having a fixed element and a movable element wherein one or the other of the fixed element and the movable element has at least one radially-extended stop or overdeflection limiter. A fixed overlayer plate forms an aperture. The aperture is sized to minimize vignetting and may be beveled on the margin. Overdeflection limitation occurs during deflection before the movable element can impinge on an underlying electrode. The overdeflection limiter may be conveniently placed adjacent a gimbaled hinge. ## Claims ### Claim 1 A double-gimbaled micromachined mirror structure for parallel-plate electrostatic operation, said mirror structure comprising: a frame; a mirror; a gimbal around said mirror; a plurality of hinge structures at four positions on said gimbal, a first pair of said hinge structures connecting said mirror to said gimbal and a second pair of said hinge structures connecting said frame to said gimbal, said hinge structures permitting motion substantially only normal to said mirror and wherein adjacent each element of said second pair is a tab extension from said mirror for serving as rotational displacement limitation; and overhanging structure adjacent each of said four positions and disposed to confront each said tab extension to limit rotational displacement of said mirror. ### Claim 2 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure and said mirror are maintained in sufficient differential in potential to permit detection of contact of said overhanging structure and said mirror through detection of voltage change. ### Claim 3 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure and said mirror are maintained in sufficient differential in potential to permit detection of contact of said overhanging structure and said mirror through detection of current change. ### Claim 4 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure and said mirror are maintained in equipotential. ### Claim 5 (depends on 1) The apparatus according to claim 1 wherein said detectable differential is sufficiently small to inhibit arcing upon contact between said overhanging structure and said mirror or gimbal. ### Claim 6 (depends on 1) The apparatus according to claim 1 wherein each of said first pair of hinge structures includes a gimbal wraparound for serving as rotational displacement limitation in confrontation with said overhanging structure. ### Claim 7 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure is disposed to provide a clear aperture at all design viewing angles of said mirror. ### Claim 8 (depends on 1) The apparatus according to claim 1 wherein said detectable differential is sufficiently small to inhibit arcing upon contact between said overhanging structure and said mirror or gimbal. ### Claim 9 A double-gimbaled micromachined mirror structure for parallel-plate electrostatic operation, said mirror structure comprising: a frame; a mirror; a gimbal around said mirror; a plurality of hinge structures at four positions on said gimbal, a first pair of said hinge structures connecting said mirror to said gimbal and a second pair of said hinge structures connecting said frame to said gimbal, said hinge structures permitting motion substantially only normal to said mirror and wherein adjacent each element of said first pair is a gimbal wraparound for serving as rotational displacement limitation; and overhanging structure adjacent each of said four positions and disposed to confront each said gimbal wraparound to limit rotational displacement of said mirror. ### Claim 10 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure and said mirror are maintained in sufficient differential in potential to permit detection of contact of said substrate and said mirror through detection of voltage change. ### Claim 11 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure and said mirror are maintained in sufficient differential in potential to permit detection of contact of said substrate and said mirror through detection of current change. ### Claim 12 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure and said mirror are maintained in equipotential. ### Claim 13 (depends on 9) The apparatus according to claim 9 wherein said detectable differential is sufficiently small to inhibit arcing upon contact between said mirror and said overhang. ### Claim 14 (depends on 9) The apparatus according to claim 9 wherein near each element of said second pair is a tab extension from said overhanging structure for serving as rotational displacement limitation on said mirror. ### Claim 15 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure is disposed to provide a clear aperture at all design viewing angles of said mirror. ### Claim 16 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure is disposed to provide a clear aperture at all design viewing angles of said mirror. ### Claim 17 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure is disposed over said mirror and mounted on a flipped SOI handle structure. ### Claim 18 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure is disposed over said mirror and mounted on a flipped SOI handle structure. ### Claim 19 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure is disposed over said mirror and formed in a bevel etched by potassium hydroxide. ### Claim 20 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure is disposed over said mirror and formed in a bevel etched by potassium hydroxide. ### Claim 21 (depends on 1) The apparatus according to claim 1 wherein said overhanging structure is disposed over said mirror and formed of a thinned silicon wafer. ### Claim 22 (depends on 9) The apparatus according to claim 9 wherein said overhanging structure is disposed over said mirror and formed of a thinned silicon wafer. ### Claim 23 (depends on 1) The apparatus according to claim 1 wherein said hinge structures are folded longitudinal gimbal hinge structures. ### Claim 24 (depends on 9) The apparatus according to claim 9 wherein said hinge structures are folded longitudinal gimbal hinge structures. ### Claim 25 (depends on 1) The apparatus according to claim 1 wherein said folded longitudinal gimbal hinge structures attached to the gimbal are recessed into the mirror. ### Claim 26 (depends on 1) The apparatus according to claim 1 wherein said mirror is round.