Physical quantity sensor and electronic apparatus

• US 9,817,020 B2
• Filed: 09/04/2015
• Issued: 11/14/2017
• Est. Priority Date: 08/17/2011
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yoda, Mitsuhiro
• Primary Examiner(s): West, Paul
• Assistant Examiner(s): ZHONG, XIN Y
• Application Number:
  US14/846,463
• Publication Number:
  US 20150377919A1
• Time in Patent Office: 802 Days
• Field of Search: 7351432, 7351436, 7351437, 7351438
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

An acceleration sensor includes a base substrate provided with a first recess part, and a sensor part located on the first recess part and swingably supported in a depth direction of the first recess part by a support part, wherein the sensor part is sectioned into a first part and a second part by the support part, includes a movable electrode part in the first part and the second part, a through hole is provided at least at an end side in the second part larger in mass than the first part, and the base substrate includes a fixed electrode part in a position opposed to the movable electrode part in the first recessed part, and a second recess part deeper than the first recess part is provided in a position opposed to the end side of the sensor part.

Claims

1. A physical quantity sensor comprising:

a base substrate provided with a first recess having a first bottom surface, a second recess having a second bottom surface, and a base ledge surrounding the first and second recesses, the second bottom surface being deeper than the first bottom surface, the base substrate being made of an insulating material;

first and second fixed electrodes that are provided in the first recess;

a conducting part that is provided in the second recess; and

a sensor substrate that is made of a low-resistance conductive semiconductor material and that is configured with;

a sensor that is located above the base substrate by way of the first and second recesses;

a frame that is provided on the base ledge, the frame being spaced apart from the sensor via a gap; and

a support extending in a first direction, the support physically connecting the sensor to the frame, the sensor being movably supported by the support so that the sensor moves in a depth direction of the first recess,

wherein the sensor is sectioned into a first part and a second part by the support, a first overlapped area in the first part overlapped between the first part and the first fixed electrode in a plan view corresponds to a first movable electrode, a second overlapped area in the second part overlapped between the second part and the second fixed electrode in the plan view corresponds to a second movable electrode, the second part being larger in mass than the first part so that the second part having an additional mass area at an edge of the second part, the additional mass area having three sides, and a through hole is provided at least in one of the first part and the second part,

the second recess is overlapped with the additional mass area of the sensor in the plan view,

the additional mass area is laterally shifted from the second fixed electrode in the plan view,

the conducting part is electrically connected to the first and second movable electrodes and the frame, and the conducting part outwardly extends away from the three sides of the additional mass area in the plan view,

electrostatic capacitances between the sensor and the first and second fixed electrodes are detected by only the first and second fixed electrodes, and

the frame and the base ledge are bonded by anodic bonding.

2. The physical quantity sensor according to claim 1, wherein

a plurality of through holes are provided along the first direction of the support, and

each of the plurality of through holes is in a strip shape in the plan view.

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

a third bottom surface is provided in the first bottom surface of the first recess, the third bottom surface is deeper than the first bottom surface, the third bottom surface is located closer to an edge of the first part of the sensor than the support, and the first and third bottom surfaces are continuously provided via a first step.

4. The physical quantity sensor according to claim 2, wherein

a third bottom surface is provided in the first bottom surface of the first recess, the third bottom surface is deeper than the first bottom surface, the third bottom surface is located closer to an edge of the first part of the sensor than the support, and the first and third bottom surfaces are continuously provided via a first step.

5. An electronic apparatus comprising the physical quantity sensor according to claim 1.