# US 10,371,939 B2 · Apparatus providing over-travel protection for actuators > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,939 B2 - Document ID: US10371939B2 - Status: Granted - Kind: B2 - Application number: 15/836,536 - Filed: 2017-12-08 - Published: 2019-06-13 - Granted: 2019-08-06 - Earliest claimed: 2017-12-08 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: William Craig McDonald; James Norman Hall; Adam Joseph Fruehling - Web page: https://patentgrep.com/patent/US10371939B2 ## CPC - G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract One or more apparatus providing over-travel protection for actuators are disclosed. An example apparatus includes a mirror; a first plate coupled to the mirror; and a support post coupled the first plate, the support post structured to prevent the mirror from moving within a threshold distance to a second plate. ## Claims ### Claim 1 An apparatus in a pixel of a spatial light modulator, the apparatus comprising: a mirror; a first plate coupled to the mirror; a flexural beam coupled to the first plate; a second plate; and a support post coupled to the first plate via the flexural beam, the support post structured to prevent the mirror against moving within a threshold distance from the second plate, the flexural beam, the support post, and the first plate integrally formed of a same conductive material. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the threshold distance corresponds to a collapsing point. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the threshold distance corresponds to one third of a displacement distance between the first plate and the second plate. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein, when a voltage is applied to the second plate, the first plate moves toward the second plate. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first plate and the second plate are electrodes. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein a top of the support post is between the mirror and the second plate and the mirror is partially overlapping the support post. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the support post is to prevent the first plate against moving within the threshold distance from the second plate by preventing the mirror from moving past the support post. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the threshold distance corresponds to (A) a first distance between the mirror and the first plate and (B) a second distance between the first plate and the second plate in a neutral position, the neutral position corresponding to when zero volts are applied to the second plate. ### Claim 9 (depends on 1) The apparatus of claim 1, further including a structural plate to house the mirror, the structural plate being coupled to the first plate via attachments. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the support post is grounded to ground the first plate. ### Claim 11 An apparatus in a pixel of a spatial light modulator, the apparatus comprising: a mirror attached to a first plate; a support post coupled to the first plate, the support post including a ledge that extends outward from a top of the support post that is between a second plate and the mirror, the mirror partially overlapping the ledge; and a processor configured to apply an overdrive voltage to the second plate to pull the first plate from a first position to a second position lower than the top of the support post, wherein the pulling of the first plate to the second position causes the ledge of the support post to flex toward the second plate, the ledge to prevent the first plate from touching the second plate. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the support post is structured to prevent the mirror against moving within a threshold distance from the second plate. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the ledge corresponds to a spring constant. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the processor is further configured to apply a voltage to the second plate to pull the first plate from the first position to a third position, wherein the third position corresponds to the mirror resting on the ledge at a height even with the top of the support post, the voltage causing an electrostatic force pulling the first plate toward the second plate. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the first plate is closer to the second plate in the second position than in the third position. ### Claim 16 (depends on 14) The apparatus of claim 14, wherein the processor is further configured to apply the overdrive voltage followed by a low voltage to push the first plate further away from the second plate to a fourth position, the fourth position corresponding to the first plate being above the top of the support post. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the first position corresponds to a position of the first plate when zero volts are applied to the second plate. ### Claim 18 (depends on 14) The apparatus of claim 14, wherein the ledge applies a force opposite the electrostatic force to prevent the first plate from collapsing at the second position. ### Claim 19 (depends on 16) The apparatus of claim 16, wherein: the ledge corresponds to a spring constant that applies a force opposite the electrostatic force to prevent the first plate from collapsing at the second position; and when the processor applies the low voltage after the overdrive voltage, the spring constant of the ledge provides upward force to push the first plate away from the second plate to the fourth position.