SENSOR

• US 20080264167A1
• Filed: 04/16/2008
• Published: 10/30/2008
• Est. Priority Date: 04/27/2007
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Kandori, Atsushi, Nagae, Kenichi, Majima, Masao
• Granted Patent: US 8,393,211 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 15/097 by vibratory elements

Abstract

A sensor includes a detecting oscillator supported in such a manner that the detecting oscillator is allowed to oscillate; first and second electrodes; a detecting electrode facing the first and second electrodes; and signal supplying units configured to supply first and second AC signals respectively to the first and second electrodes. Either the first and second electrodes or the detecting electrode is provided on the detecting oscillator. The first and second AC signals respectively supplied to the first and second electrodes by the signal supplying units cause the detecting oscillator to be maintained at a neutral position for detection without being displaced when no physical quantity is input. When the detecting oscillator is displaced, an input physical quantity is detected on the basis of a signal corresponding to charges induced at the detecting electrode by the first and second AC signals supplied respectively to the first and second electrodes.

Claims

1. A sensor comprising:

a detecting oscillator supported in such a manner that the detecting oscillator is allowed to oscillate;

first and second electrodes configured to receive application of alternating-current signals;

a detecting electrode facing the first and second electrodes; and

a signal supplying unit configured to supply first and second alternating-current signals respectively to the first and second electrodes,

wherein either the first and second electrodes or the detecting electrode is provided on the detecting oscillator, and wherein the first and second alternating-current signals respectively supplied to the first and second electrodes cause the detecting oscillator to be maintained at a neutral position for detection without being displaced when no physical quantity is input, and when the detecting oscillator is displaced, an input physical quantity is detected on the basis of a signal corresponding to charges induced at the detecting electrode by the first and second alternating-current signals supplied respectively to the first and second electrodes.

2. The sensor according to claim 1, further comprising an amount-of-charges measurement unit configured to assign a reference potential to the detecting electrode and to detect the physical quantity on the basis of the signal corresponding to the induced charges, wherein the first and second alternating-current signals are alternating-current signals that alternate with reference to the reference potential and that have a same frequency and mutually opposite phases.

3. The sensor according to claim 1, further comprising a reference oscillator and a reference oscillation generator configured to cause oscillation of the reference oscillator with reference to a reference neutral position, wherein the reference oscillator supports the detecting oscillator in such a manner that the detecting oscillator is allowed to oscillate.

4. The sensor according to claim 3, wherein the detecting oscillator is supported in such a manner that the detecting oscillator is allowed to oscillate rotationally about a first rotation axis, the reference oscillation generator causes the reference oscillator to oscillate rotationally about a second rotation axis, and an angular velocity is detected as the physical quantity using oscillation of the detecting oscillator caused by a Coriolis force generated in relation to the angular velocity.

5. The sensor according to claim 3, wherein the first and second electrodes and the detecting electrode are all provided on the detecting oscillator or the reference oscillator.

6. The sensor according to claim 1, wherein the detecting electrode is formed of segments individually corresponding to the first and second electrodes.

7. The sensor according to claim 1, wherein the first and second electrodes or the detecting electrode is formed within a portion of the detecting oscillator, the portion of the detecting oscillator being insulated by an insulator from an other portion of the detecting oscillator.

8. The sensor according to claim 1, further comprising an electrostatic shield provided between the first and second electrodes.

9. The sensor according to claim 1, further comprising third and fourth electrodes and a second detecting electrode facing the third and fourth electrode, wherein the first and third electrodes are disposed plane-symmetrically with respect to the detecting oscillator and the second and fourth electrodes are disposed plane-symmetrically with respect to the detecting oscillator, the signal supplying unit further supplies the second alternating-current signal to the third electrode and the first alternating-current signal to the fourth electrode, and when the detecting oscillator is displaced, the physical quantity is detected on the basis of the signal corresponding to the charges induced at the detecting electrode by the first and second alternating-current signals supplied respectively to the first and second electrodes and on the basis of a signal corresponding to charges induced at the second detecting electrode by the first and second alternating-current signals supplied respectively to the fourth and third electrodes.