Actuator for oscillator

• US 6,497,147 B2
• Filed: 03/16/2001
• Issued: 12/24/2002
• Est. Priority Date: 03/17/2000
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Kato, Manabu, Kurachi, Hideya
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/809,223
• Publication Number:
  US 20010022106A1
• Time in Patent Office: 648 Days
• Field of Search: 735/041.2, 735/040.2, 735/040.4, 735/041.3, 735/041.4, 735/041.5, 735/041.6
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

An actuator for an oscillator which is capable of minimizing the fluctuation of the detection error of the oscillation condition of an electrostatic driven oscillator and shortening rise time of the oscillation amplitude of the electrostatic driven oscillator during starting. An actuator oscillates a drive frame and a detecting frame in the X-direction by outputting the drive signal to an electrode and detects the displacement of the drive frame in the X-direction as the displacement signal. The actuator generates a direct-current voltage component of the drive signal controlled to be increased or decreased based on the detected displacement signal and an alternating voltage component of the drive signal having a constant amplitude to maintain the constancy of the oscillation amplitude of the drive frame based on the detected displacement signal. During starting, the actuator generates an alternating voltage component of the drive signal having a larger amplitude compared to at normal operation condition.

Claims

1. An actuator for an oscillator comprising:

an electrostatic driven oscillator;

an oscillator driving means for oscillating the electrostatic driven oscillator by outputting a drive signal thereto;

a displacement detecting means for detecting a displacement according to an oscillation of the electrostatic driven oscillator as a displacement signal;

an amplitude adjusting means for controlling the generation of the drive signal outputted from the oscillator driving means based on the detected displacement signal;

the amplitude adjusting means including an alternating voltage component generating means for generating an alternating voltage component of the drive signal having a first amplitude during normal operation and for generating the alternating voltage component of the drive signal having a second amplitude which is larger than the first amplitude during a starting operation and a direct-current voltage component generating means for generating a direct current voltage component of the drive signal controlled to be increased or decreased based on the detected displacement signal;

wherein an oscillation amplitude of the electrostatic driven oscillator is adjusted to be constant by controlling an oscillation force of the electrostatic driven oscillator based on an incorporated signal consisting of a direct-current voltage component and an alternating voltage component having a first amplitude at the normal operation; and

the oscillation amplitude of the electrostatic driven oscillator is increased by driving a larger oscillation drive force to the electrostatic driven oscillator based on the incorporated signal consisting of the direct-current voltage component and the alternating voltage component having a second amplitude at the starting operation.

2. The actuator for oscillator according to claim 1, wherein the alternating voltage component generating means is comprised of an alternating voltage component generating portion for generating the alternating voltage component of a predetermined amplitude and an amplifying portion for generating the alternating voltage component of the drive signal having the first amplitude and the alternating voltage component of the drive signal having the second amplitude by amplifying the alternating voltage component of the predetermined amplitude by a different amplification ratio in accordance with the distinction between the normal operation and the starting operation.

3. The actuator for oscillator according to claim 1, wherein the alternating voltage component generating means is comprised of a first signal route for generating the alternating voltage component of the drive signal having the first amplitude, a second signal route for generating the alternating voltage component of the drive signal having the second amplitude, and a switching portion for switching the first signal route and the second signal route in accordance with the distinction of the normal operation and the starting operation.

5. The actuator for oscillator according to claim 1, wherein the normal operation and the starting operation are distinguished by the passage of time after starting.

6. The actuator for oscillator according to claim 1, wherein the normal operation and the starting operation are distinguished by the comparison between a predetermined amplitude during starting and the oscillation amplitude of the electrostatic driven oscillator detected based on the displacement signal.

7. The actuator for oscillator according to claim 1, wherein the normal operation and the starting operation are distinguished by the voltage of the direct-current voltage component.

8. The actuator for oscillator according to claim 1, wherein the normal operation and the starting operation are distinguished by the comparison between the direct-current voltage component and a predetermined voltage at the starting operation.

9. The actuator for oscillator according to claim 1, wherein the direct-current voltage component of the drive signal is controlled to be increased or decreased to be proportional to differences between a predetermined amplitude and the oscillation amplitude of the electrostatic driven oscillator detected based on the displacement signal.

10. The actuator for oscillator according to claim 1, wherein the direct-current voltage component of the drive signal is controlled to be increased or decreased to be proportional to a value performing time integration of differences between a predetermined amplitude and the oscillation amplitude of the electrostatic driven oscillator detected based on the displacement signal.

11. The actuator for oscillator according to claim 1, wherein the direct-current voltage component of the drive signal is controlled to be increased or decreased to be proportional to an addition of a value proportional to differences between a predetermined amplitude and the oscillation amplitude and a value performing time integration to differences between the predetermined amplitude and the oscillation amplitude of the electrostatic driven oscillator detected based on the displacement signal.

12. The actuator for oscillator according to claim 1, wherein the alternating voltage component of the drive signal is generated having a phase-contrast by approximately 90 degrees relative to the displacement signal.

4. An actuator for oscillator comprising:

an oscillator driving means for oscillating an electrostatic driven oscillator by outputting a drive signal thereto;

a displacement detecting means for detecting a displacement according to an oscillation of the electrostatic driven oscillator as a displacement signal; and

an amplitude adjusting means for controlling the generation of the drive signal outputted from the oscillator driving means based on the detected displacement signal;

the amplitude adjusting means including an alternating voltage component generating means for generating an alternating voltage component of the drive signal having a constant amplitude by phase-shifting and amplifying the displacement signal by a first amplification ratio during a normal operation and for generating the alternating voltage component of the drive signal by amplifying the displacement signal by a second amplification ratio which is larger than the first amplification ratio during a starting operation and including a direct-current voltage component generating means for generating a direct-current voltage component of the drive signal controlled to be increased or decreased based on the detected displacement signal;

wherein an oscillation amplitude of the electrostatic driven oscillator is adjusted to be constant by controlling an oscillation drive force of the electrostatic driven oscillator based on an incorporated signal consisting of the direct-current voltage component and the alternating voltage component having a constant amplitude amplified by the first amplification ratio at the normal operation; and

wherein the oscillation amplitude of the electrostatic driven oscillator is increased by supplying a larger oscillation drive force relative to the electrostatic driven oscillator based on an incorporated drive signal consisting of the direct-current voltage component and the alternating voltage component amplified by the second amplification ratio during the starting operation.