Physical quantity sensor

• US 8,250,917 B2
• Filed: 02/02/2009
• Issued: 08/28/2012
• Est. Priority Date: 02/06/2008
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Naruse, Hideto, Kikuchi, Takayuki
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Redmann, Gregory J
• Application Number:
  US12/364,074
• Publication Number:
  US 20090205421A1
• Time in Patent Office: 1,303 Days
• Field of Search: 735/041.2
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719

Abstract

A physical quantity sensor includes a vibration element having drive arm sections and a detection arm section, a driving circuit generating a driving signal for driving the drive arm sections with a first driving line and a second driving line, and a detection circuit detecting a detected signal from the detection arm section with a first detection line and a second detection line. At least one of the first driving line and the second driving line is wired so that a static coupling is generated with respect to the first detection line and the second detection line.

Claims

1. A physical quantity sensor, comprising:

a vibrating element having a drive arm section and a detection arm section;

a driving circuit generating a driving signal for driving the drive arm section with a first driving line and a second driving line; and

a detection circuit detecting a detected signal from the detection arm section with a first detection line and a second detection line,

wherein at least one of the first driving line and the second driving line is wired so that a static coupling is generated between a portion of wiring of at least one of the first and second driving lines disposed adjacent to a portion of wiring of at least one of the first and second detection lines,

wherein the driving signal carried by the at least one of the first and the second driving lines is transmitted to the at least one of the first and second detection lines via the static coupling, and

wherein the detection circuit performs a testing operation of the physical quantity sensor based upon the driving signal transmitted to the at least one of the first and second detection lines via the static coupling.

2. The physical quantity sensor according to claim 1, wherein one of the first driving line and the second driving line is wired so that different static couplings are generated with respect to the first detection line and the second detection line.

3. The physical quantity sensor according to claim 1, wherein:

a first inverter and a second inverter are coupled in series with one of the first driving line and the second driving line; and

a wiring line coupling the driving circuit and the first inverter, and another wiring line coupling the first inverter and the second inverter are wired so that static couplings are generated with respect to the first detection line and the second detection line.

4. The physical quantity sensor according to claim 1, wherein a wiring path of at least one of the first driving line and the second driving line is switched so that the static coupling is not generated in a normal operation state.

5. The physical quantity sensor according to claim 2, wherein a wiring path of at least one of the first driving line and the second driving line is switched so that the static coupling is not generated in a normal operation state.

6. The physical quantity sensor according to claim 3, wherein a wiring path of at least one of the first driving line and the second driving line is switched so that the static coupling is not generated in a normal operation state.

7. The physical quantity sensor according to claim 1, wherein at least one of the first driving line and the second driving line is wired by an indirect route with respect to the first detection line and the second detection line so that the static coupling is generated between the portion of wiring of at least one of the first and second driving lines disposed adjacent to the portion of wiring of at least one of the first and second detection lines.