# US 2012/0073940 A1 · Actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0073940 A1 - Document ID: US20120073940A1 - Status: Published application - Kind: A1 - Application number: 13/070,250 - Filed: 2011-03-23 - Published: 2012-03-29 - Earliest claimed: 2010-09-24 - Assignees: Kabushiki Kaisha Toshiba - Inventors: Kei MASUNISHI; Tamio Ikehashi; Yasushi Tomizawa; Akihiro Koga - Web page: https://patentgrep.com/patent/US20120073940A1 ## CPC - H01H 59/0009: {making use of micromechanics} - H01G 5/18: due to change in inclination, e.g. by flexing, by spiral wrapping - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10) ## Abstract According to one embodiment, an actuator includes a substrate, a lower electrode disposed on the substrate, an upper electrode, a support and a driving unit. The upper electrode is opposed to the lower electrode. The support supports the upper electrode. The driving unit is connected between the lower electrode and the upper electrode and feeds a driving voltage. The driving voltage at which the lower and upper electrodes start to come into contact with each other is defined as a pull-in voltage. A capacitance between the lower and upper electrodes is defined as a pull-in capacitance. There exist a first region and a second region. In the second region, a change rate of a capacitance ratio changes more slowly than in the first region, when the absolute value of the potential difference is further increased. The driving unit feeds the driving voltage in the second region. ## Claims ### Claim 1 An actuator comprising: a substrate; a lower electrode disposed on the substrate; an upper electrode opposed to the lower electrode, a distance between the lower electrode and the upper electrode being variable; a support having one end fixed to the substrate and one other end connected to the upper electrode and supporting the upper electrode, the support having a higher creep resistance than the upper electrode; and a driving unit connected between the lower electrode and the upper electrode and feeding a driving voltage applied between the lower electrode and the upper electrode, the driving voltage at which the lower electrode and the upper electrode start to come into contact with each other when an absolute value of a potential difference between the lower electrode and the upper electrode is increased being defined as a pull-in voltage, a capacitance between the lower electrode and the upper electrode when the pull-in voltage is applied being defined as a pull-in capacitance, there existing a first region where a change rate of a capacitance ratio relative to the pull-in capacitance rapidly changes when the absolute value of the potential difference is increased to the pull-in voltage or larger and a second region where the change rate changes more slowly than in the first region, when the absolute value of the potential difference is further increased, and the driving unit feeding the driving voltage in the second region. ### Claim 2 (depends on 1) The actuator according to claim 1, wherein the support has ductility lower than the upper electrode. ### Claim 3 (depends on 1) The actuator according to claim 1, wherein the change rate in the second region is 0.4 (1/volt) or less. ### Claim 4 (depends on 1) The actuator according to claim 1, wherein the change rate in the second region is 0.2 (1/volt) or less. ### Claim 5 (depends on 1) The actuator according to claim 1, wherein the change rate in the second region is 0.6 (1/volt) or less. ### Claim 6 (depends on 1) The actuator according to claim 1, wherein the support includes at least one of oxide, nitride and oxynitride. ### Claim 7 (depends on 1) The actuator according to claim 1, wherein the support includes at least one of silicon dioxide, silicon nitride and silicon oxynitride. ### Claim 8 (depends on 1) The actuator according to claim 1, wherein the support includes at least one of polysilicon, silicon, tungsten and titanium aluminum. ### Claim 9 (depends on 1) The actuator according to claim 1, further comprising an RF electrode disposed opposed to the lower electrode. ### Claim 10 (depends on 1) The actuator according to claim 1, further comprising an RF electrode disposed parallel to the lower electrode. ### Claim 11 An actuator comprising: a substrate; a lower electrode disposed on the substrate; an upper electrode opposed to the lower electrode, a distance between the lower electrode and the upper electrode being variable; a support having one end fixed to the substrate and one other end connected to the upper electrode and supporting the upper electrode, the support having a higher creep resistance than the upper electrode; and a driving unit connected between the lower electrode and the upper electrode and feeding a driving voltage applied between the lower electrode and the upper electrode, the driving voltage at which the lower electrode and the upper electrode start to come into contact with each other when an absolute value of a potential difference between the lower electrode and the upper electrode is increased being defined as a pull-in voltage, and the driving unit feeding a first driving voltage having the absolute value of the potential difference that is the pull-in voltage or larger, and then feeding a second driving voltage having the absolute value of the potential difference that is smaller than the first driving voltage. ### Claim 12 (depends on 11) The actuator according to claim 11, wherein the support has ductility lower than the upper electrode. ### Claim 13 (depends on 11) The actuator according to claim 11, wherein the support includes at least one of oxide, nitride and oxynitride. ### Claim 14 (depends on 11) The actuator according to claim 11, wherein the support includes at least one of silicon dioxide, silicon nitride and silicon oxynitride. ### Claim 15 (depends on 11) The actuator according to claim 11, wherein the support includes at least one of polysilicon, silicon, tungsten and titanium aluminum. ### Claim 16 (depends on 11) The actuator according to claim 11, further comprising an RF electrode disposed opposed to the lower electrode. ### Claim 17 (depends on 11) The actuator according to claim 11, further comprising an RF electrode disposed parallel to the lower electrode. ### Claim 18 (depends on 11) The actuator according to claim 11, wherein the second driving voltage is the pull-in voltage or higher. ### Claim 19 (depends on 11) The actuator according to claim 11, wherein the second driving voltage is the pull-in voltage or lower. ### Claim 20 (depends on 11) The actuator according to claim 11, wherein the upper electrode includes at least one of aluminum, aluminum alloy and gold.