Micromechanical electrostatic resonator

• US 7,215,061 B2
• Filed: 11/18/2004
• Issued: 05/08/2007
• Est. Priority Date: 12/04/2003
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Furuhata, Makoto, Kihara, Ryuji, Nakajima, Takuya
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US10/990,411
• Publication Number:
  US 20050151442A1
• Time in Patent Office: 901 Days
• Field of Search: 310/309
• US Class Current: 310/309
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 2009/02503 Breath-like, e.g. Lam? mode, wine-glass mode
• CPC Class Codes: H03H 2009/02519 Torsional
• CPC Class Codes: H03H 3/0072 of microelectro-mechanical resonators or networks micromembranes or microbeams B81B2203/01; manufacture of microstructural devices in general B81C
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/02433 Means for compensation or elimination of undesired effects
• CPC Class Codes: H03H 9/1057 for microelectro-mechanical devices
• CPC Class Codes: H03H 9/2431 Ring resonators
• CPC Class Codes: H03H 9/2436 Disk resonators
• CPC Class Codes: H03H 9/2457 Clamped-free beam resonators
• CPC Class Codes: H03H 9/2463 Clamped-clamped beam resonators

Abstract

Exemplary embodiments of the invention provide a micromechanical electrostatic resonator which designs high frequency, increases a ratio of output voltage to input voltage, and designs low drive voltage or reduced power consumption. A micromechanical electrostatic resonator of exemplary embodiments includes a plate-shaped vibration body, a pair of electrodes arranged oppositely to each other at both sides of the vibration body with a gap from an outer circumferential portion of the vibration body, a feeding device to apply in-phase alternating-current power to the pair of electrodes, and a detecting device to obtain an output corresponding to a change in capacitance between the vibration body and the electrodes. The planar shape of the vibration body takes a shape having a curved outline which comprises a neck portion.

Claims

1. A micromechanical electrostatic resonator, comprising:

a planar-shaped vibration body;

a pair of excitation electrodes arranged oppositely to each other at both sides of the vibration body with a gap from an outer circumferential portion of the vibration body;

a feeding device to apply in-phase alternating-current power to the pair of excitation electrodes; and

a detecting device to obtain an output corresponding to a change in capacitance between the vibration body and the excitation electrodes,

the planar shape of the vibration body taking a shape having a curved outline which includes neck portions,

the outline of the planar shape of the vibration body including circular arc portions and the neck portions, both ends of each of the neck portions being smoothly connected between the circular arc portions.

2. The micromechanical electrostatic resonator according to claim 1,

the vibration body being supported by a supporting portion formed on a substrate and being constructed in a shape which is stretched in the vicinity of the supporting portion.

3. The micromechanical electrostatic resonator according to claim 2, further comprising:

a wiring layer conductively connected to at least one of the vibration body and the excitation electrode,

a distance from the wiring layer to the substrate being larger than a distance from the at least one of vibration body and the excitation electrode to the substrate.

4. The micromechanical electrostatic resonator according to claim 2,

the substrate being a substrate made of an insulator.

5. The micromechanical electrostatic resonator according to claim 4,

the substrate being made of glass.

6. The micromechanical electrostatic resonator according to claim 1,

the vibration body being made of at least one of a silicon layer and a silicon compound layer which is constructed on a silicon substrate serving as the substrate.

7. A micromechanical electrostatic resonator, comprising:

a planar-shaped vibration body;

a pair of excitation electrodes arranged oppositely to each other at both sides of the vibration body with a gap from an outer circumferential portion of the vibration body;

a feeding device to apply in-phase alternating-current power to the pair of excitation electrodes; and

a detecting device to obtain an output corresponding to a change in capacitance between the vibration body and the excitation electrodes,

the planar shape of the vibration body taking a shape having a curved outline which includes neck portions

the vibration body being supported by a supporting portion formed on a substrate and being constructed in a shape which is stretched in the vicinity of the supporting portion,

a wiring layer conductively connected to at least one of the vibration body and the excitation electrode,

a distance from the wiring layer to the substrate being larger than a distance from the at least one of vibration body and the excitation electrode to the substrate,

the wiring layer being formed on an insulating layer which includes a surface spaced from the substrate, farther than a surface on which the at least one of vibration body and the excitation electrode is to be formed.

8. The micromechanical electrostatic resonator according to claim 7,

at least one of the vibration body and the excitation electrode being constructed on a surface of an insulator which is formed on the substrate and the insulating layer having a dielectric constant lower than the insulator.

9. The micromechanical electrostatic resonator according to claim 7,

the insulating layer being a porous film.

10. The micromechanical electrostatic resonator according to claim 7,

a space being provided between the wiring layer and the substrate.