Apparatus for detecting a physical quantity acting as an external force and method for testing and manufacturing this apparatus

• US 6,894,482 B2
• Filed: 04/01/2004
• Issued: 05/17/2005
• Est. Priority Date: 12/28/1989
• Status: Expired due to Fees

• Current Assignee: Wacoh Company
• Original Assignee: Kazuhiro Okada
• Inventors: Okada, Kazuhiro
• Primary Examiner(s): Zarneke, David
• Assistant Examiner(s): Nguyen, Jimmy
• Application Number:
  US10/816,548
• Publication Number:
  US 20040189340A1
• Time in Patent Office: 411 Days
• Field of Search: 324/158.1, 324/117.R, 324/117.H, 324/73.1, 324/765, 324/754, 73/1.D, 73/13.7, 735/17.R, 735/17.B, 73/1.C, 73/1.B, 73/4.R, 738/620.63, 738/626.8, 738/629.3, 735/17.D
• US Class Current: 324/750.22
• CPC Class Codes: G01L 1/148 using semiconductive material, e.g. silicon
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 25/00 Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
• CPC Class Codes: G01L 5/162 of piezoresistors
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• 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 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

A sensor comprises a semiconductor pellet (10) including a working portion (11) adapted to undergo action of a force, a fixed portion (13) fixed on the sensor body, and a flexible portion (13) having flexibility formed therebetween, a working body (20) for transmitting an exterted force to the working portion, and detector means (60-63) for transforming a mechanical deformation produced in the semiconductor pellet to an electric signal to thereby detect a force exerted on the working body as an electric signal. A signal processing circuit is applied to the sensor. This circuit uses analog multipliers (101-109) and analog adders/subtracters (111-113), and has a function to cancel interference produced in different directions. Within the sensor, two portions (E3, E4-E8) located at positions opposite to each other and producing a displacement therebetween by action of a force are determined. By exerting a coulomb force between both the portions, the test of the sensor is carried out. Further, a pedestal (21, 22) is provided around the working body (20). The working body and the pedestal are located with a predetermined gap or spacing therebetween. A displacement of the working body is caused to limitatively fall within a predetermined range corresponding to the spacing. The working body and the pedestal are provided by cutting a same common substrate (350, 350′).

Claims

1. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along a XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force,

said method comprising the steps of;

providing a deviation electrode and a fixed electrode, said deviation electrode being located at a position which deviates along with said working body and said fixed electrode being fixed to said substrate so as to face said deviation electrode;

applying a voltage between said deviation electrode and said fixed electrode so that Coulomb force is produced which causes spatial deviation of said working body in an X-axis direction of said XYZ three-dimensional coordinate system;

detecting an electric signal transformed by said transducer while said spatial deviation is caused by applying said voltage; and

testing an operation of said acceleration sensor with respect to said X-axis direction based on a relationship between said applied voltage and said detected electric signal.

2. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along an XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force,

said method comprising the steps of;

providing a deviation electrode and a fixed electrode, said deviation electrode being located at a position which deviates along with said working body and said fixed electrode being fixed to said substrate so as to face said deviation electrode;

applying a voltage between said deviation electrode and said fixed electrode so that Coulomb force is produced which causes spatial deviation of said working body in a Z-axis direction of said XYZ three-dimensional coordinate system;

detecting an electric signal transformed by said transducer while said spatial deviation is caused by applying said voltage; and

testing an operation of said acceleration sensor with respect to said Z-axis direction based on a relationship between said applied voltage and said detected electric signal.

3. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along an XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force,

said method comprising the steps of;

providing a deviation electrode and a fixed electrode, said deviation electrode being located at a position which deviates along with said working body and said fixed electrode being fixed to said substrate so as to face said deviation electrode;

applying a first voltage between said deviation electrode and said fixed electrode so that Coulomb force is produced which causes first spatial deviation of said working body in an X-axis direction of said XYZ three-dimensional coordinate system;

detecting a first electric signal transformed by said transducer while said first spatial deviation is caused by applying said first voltage;

testing a first operation of said acceleration sensor with respect to said X-axis direction based on a relationship between said applied first voltage and said detected first electric signal;

applying a second voltage between said deviation electrode and said fixed electrode so that Coulomb force is produced which causes second spatial deviation of said working body in a Z-axis direction of said XYZ three-dimensional coordinate system;

detecting a second electric signal transformed by said transducer while said second spatial deviation is caused by applying said second voltage; and

testing a second operation of said acceleration sensor with respect to said Z-axis direction based on a relationship between said applied second voltage and said detected second electric signal.

4. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along an XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force;

said method comprising the steps of;

providing a first deviation electrode and a first fixed electrode, said first deviation electrode being located at a position which deviates along with said working body and said first fixed electrode being fixed to said substrate so as to face said first deviation electrode;

providing a second deviation electrode and a second fixed electrode, said second deviation electrode being located at a position which deviates along with said working body and said second fixed electrode being fixed to said substrate so as to face said second deviation electrode;

applying a first voltage between said first deviation electrode and said first fixed electrode so that Coulomb force is produced which causes first spatial deviation of said working body in an X-axis direction of said XYZ three-dimensional coordinate system;

detecting a first electric signal transformed by said transducer while said first spatial deviation is caused by applying said first voltage;

testing a first operation of said acceleration sensor with respect to said X-axis direction based on a relationship between said applied first voltage and said detected first electric signal;

applying a second voltage between said second deviation electrode and said second fixed electrode so that Coulomb force is produced which causes second spatial deviation of said working body in a Y-axis direction of said XYZ three-dimensional coordinate system;

detecting a second electric signal transformed by said transducer while said second spatial deviation is caused by applying said second voltage; and

testing a second operation of said acceleration sensor with respect to said Y-axis direction based on a relationship between said applied second voltage and said detected second electric signal.

5. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along an XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force;

said method comprising the steps of;

providing a first deviation electrode and a first fixed electrode, said first deviation electrode being located at a position which deviates along with said working body and said first fixed electrode being fixed to said substrate so as to face said first deviation electrode;

providing a second deviation electrode and a second fixed electrode, said second deviation electrode being located at a position which deviates along with said working body and said second fixed electrode being fixed to said substrate so as to face said second deviation electrode;

applying a first voltage between said first deviation electrode and said first fixed electrode so that Coulomb force is produced which causes first spatial deviation of said working body in an X-axis direction of said XYZ three-dimensional coordinate system;

detecting a first electric signal transformed by said transducer while said first spatial deviation is caused by applying said first voltage;

testing a first operation of said acceleration sensor with respect to said X-axis direction based on a relationship between said applied first voltage and said detected first electric signal;

applying a second voltage between said second deviation electrode and said second fixed electrode so that Coulomb force is produced which causes second spatial deviation of said working body in a Y-axis direction of said XYZ three-dimensional coordinate system;

detecting a second electric signal transformed by said transducer while said second spatial deviation is caused by applying said second voltage;

testing a second operation of said acceleration sensor with respect to said Y-axis direction based on a relationship between said applied second voltage and said detected second electric signal;

applying a third voltage between said first deviation electrode and said first fixed electrode so that Coulomb force is produced which causes third spatial deviation of said working body in a Z-axis direction of said XYZ three-dimensional coordinate system;

detecting a third electric signal transformed by said transducer while said third spatial deviation is caused by applying said third voltage; and

testing a third operation of said acceleration sensor with respect to said Z-axis direction based on a relationship between said applied third voltage and said detected third electric signal.

6. A method of testing an acceleration sensor,

said acceleration sensor comprising:

a substrate arranged along an XY-plane of an XYZ three-dimensional coordinate system;

a working body receiving a force and located adjacent to said substrate with a predetermined distance;

a flexible member made of silicon supporting said working body at a periphery thereof so that said working body is suspended and spatial deviation of said working body is produced by applying said force thereto;

a fixing member fixing said flexible member to said substrate; and

a transducer for transforming said spatial deviation into an electric signal that indicates a direction and a magnitude of said force;

said method comprising the steps of;

providing a first deviation electrode and a first fixed electrode, said first deviation electrode being located at a position which deviates along with said working body and said first fixed electrode being fixed to said substrate so as to face said first deviation electrode;

providing a second deviation electrode and a second fixed electrode, said second deviation electrode being located at a position which deviates along with said working body and said second fixed electrode being fixed to said substrate so as to face said second deviation electrode;

applying a first voltage between said first deviation electrode and said first fixed electrode so that Coulomb force is produced which causes first spatial deviation of said working body in an X-axis direction of said XYZ three-dimensional coordinate system;

detecting a first electric signal transformed by said transducer while said first spatial deviation is caused by applying said first voltage;

testing a first operation of said acceleration sensor with respect to said X-axis direction based on a relationship between said applied first voltage and said detected first electric signal;

applying a second voltage between said second deviation electrode and said second fixed electrode so that Coulomb force is produced which causes second spatial deviation of said working body in a Y-axis direction of said XYZ three-dimensional coordinate system;

detecting a second electric signal transformed by said transducer while said second spatial deviation is caused by applying said second voltage;

testing a second operation of said acceleration sensor with respect to said Y-axis direction based on a relationship between said applied second voltage and said detected second electric signal;

applying a third voltage between said first deviation electrode and said first fixed electrode and between said second deviation electrode and said second fixed electrode so that Coulomb force is produced which causes third spatial deviation of said working body in a Z-axis direction of said XYZ three-dimensional coordinate system;

detecting a third electric signal transformed by said transducer while said third spatial deviation is caused by applying said third voltage; and

testing a third operation of said acceleration sensor with respect to said Z-axis direction based on a relationship between said applied third voltage and said detected third electric signal.