Inertia force sensor and composite sensor for detecting inertia force

• US 8,117,914 B2
• Filed: 02/19/2008
• Issued: 02/21/2012
• Est. Priority Date: 02/20/2007
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ohuchi, Satoshi, Aizawa, Hiroyuki
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): WILLIAMS, HEZRON
• Application Number:
  US12/527,141
• Publication Number:
  US 20100071468A1
• Time in Patent Office: 1,463 Days
• Field of Search: 735/041.2, 735/143.2
• 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 15/0802 Details
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0817 for pivoting movement of the mass, e.g. in-plane pendulum
• CPC Class Codes: G01P 2015/0842 the mass being of clover leaf shape

Abstract

An inertia force sensor includes a detection element having an acceleration detection section (1). This detection element (1) has: two orthogonal arms obtained by connecting first arms (8) to second arms (10) so as to be orthogonal to each other, a support section (12) for supporting one ends of the two first arm (8), a fixation section (4) connected to the other ends of the two first arms (8), and weight sections (2) fixed to tip ends of the second arms (10). The first arm (8) has a thickness thinner than thicknesses of the second arm (10) and weight section (2) to thereby provide an increased detection sensitivity.

Claims

1. An inertia force sensor comprising a detection element having an acceleration detection section, the detection element has a fixation section having a weight section via a connecting section, an opposed substrate opposed to the weight section, and opposed electrodes formed at the respective opposed face of the weight section and the opposed substrate, the acceleration detection section is structured so that a status change caused by movability of the weight section due to distortion of the connecting section is detected by the opposed electrode to thereby detect an inertia force,

wherein:

the connecting section has a thickness thinner than a thickness of the weight section, and

the detection element has two orthogonal arm sections obtained by connecting first arm sections to second arm sections so that the first arm sections are orthogonal to the second arm sections and a support section supporting the two first arm sections, a tip end of the second arm section has the weight section, the connecting section is configured by the first arm section, and the first arm section has a thickness thinner than a thickness of the second arm section.

2. The inertia force sensor according to claim 1, wherein:

the second arm section is bent so that the tip end thereof is opposed to the second arm section.

3. The inertia force sensor according to claim 1, wherein:

the weight section and the fixation section have therebetween a frame section including therein the weight section, the frame section is connected to the weight section via the first connecting section, the fixation section is connected to the frame section and the second connecting section so as to include therein the weight section, and the first connecting section and the second connecting section have thicknesses thinner than a thickness of the weight section.

4. The inertia force sensor according to claim 3, wherein:

the first connecting section and the second connecting section are provided so as to be orthogonal to each other.

5. The inertia force sensor according to claim 1, wherein:

the fixation section has a square-like shape including therein the weight section, the connecting section is connected to a side section of the square-shaped fixation section, and the side section is fixed to a mounting substrate.

6. The inertia force sensor according to claim 1, wherein:

the detection element has a symmetrical shape.

7. An inertia force sensor including a detection element having an acceleration detection section and an angular velocity detection section, the detection element has two orthogonal arm sections obtained by connecting first arm sections to second arm sections so that the first arm sections are orthogonal to the second arm sections, a support section supporting the two first arm sections, weight sections connected to tip ends of the second arm sections, fixation sections connected to the first arm sections, an opposed substrate opposed to the weight sections, opposed electrodes formed at the respective opposed face of the weight sections and the opposed substrate, a driving electrode formed in the second arm section for outputting a driving signal for vibrating the second arm section, and a sensing electrode formed in the second arm section for sensing distortion of the second arm section to output a sensing signal, the inertia force detection section is structured so that a status change caused by movability of the weight sections due to distortion of the first arm is detected by the opposed electrodes to detect an inertia force, and the angular velocity detection section is structured so that a status change due to a Coriolis force of the weight section is detected by the sensing electrode to thereby detect an angular velocity,

wherein:

the first arm section has a thickness thinner than a thickness of the second arm section.

8. The composite inertia force sensor according to claim 7, wherein:

the second arm section is bent so that the tip end thereof is opposed to the second arm section.

9. The composite inertia force sensor according to claim 7, wherein:

the weight section and the fixation section have therebetween a frame section including therein the weight section, the frame section is connected to the second arm section via a first connecting section configured by the first arm section, the fixation section is connected to the frame section by a second connecting section, the first connecting section and the second connecting section have thicknesses thinner than a thickness of the weight section.

10. The composite inertia force sensor according to claim 9, wherein:

the first connecting section and the second connecting section are provided so as to be orthogonal to each other.

11. The composite inertia force sensor according to claim 7, wherein:

the fixation section has a square-like shape including therein the weight section, the first arm section is connected to a side section of the square-shaped fixation section, and the side section is fixed to a mounting substrate.

12. The composite inertia force sensor according to claim 7, wherein:

the detection element has a symmetrical shape.