Force detector and acceleration detector and method of manufacturing the same

• US 20040255697A1
• Filed: 07/12/2004
• Published: 12/23/2004
• Est. Priority Date: 10/12/1990
• Status: Active Grant

• Current Assignee: Kazuhiro Okada
• Original Assignee: Kazuhiro Okada
• Inventors: Okada, Kazuhiro
• Granted Patent: US 7,152,485 B2
• Time in Patent Office: Days
• US Class Current: 73/862.043
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: G01L 1/144 with associated circuitry G01L1/146 and G01L1/148 take precedence
• CPC Class Codes: G01L 5/165 using variations in capacitance
• CPC Class Codes: G01L 5/167 using piezoelectric means
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type
• CPC Class Codes: G01P 15/105 by magnetically sensitive devices
• 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

Abstract

An electrode layer is formed on the upper surface of a first substrate, and a processing for partially removing the substrate is carried out in order to allow the substrate to have flexibility. To the lower surface of the first substrate, a second substrate is connected. Then, by cutting the second substrate, a working body and a pedestal are formed. On the other hand, a groove is formed on a third substrate. An electrode layer is formed on the bottom surface of the groove. The third substrate is connected to the first substrate so that both the electrodes face to each other with a predetermined spacing therebetween. Finally, the first, second and third substrates are cut off every respective unit regions to form independent sensors, respectively. When an acceleration is exerted on the working body, the first substrate bends. As a result, the distance between both the electrodes changes. Thus, an acceleration exerted is detected by changes in an electrostatic capacitance between both the electrodes.

Claims

1. An acceleration detector detecting an acceleration component along a detection axis, said detector comprising a first capacitance element, a second capacitance element and a displacement body displaced by said acceleration component which is detected based on a difference between a capacitance value of said first capacitance element and a capacitance value of said second capacitance element.

2. The acceleration detector as set forth in claim 1, wherein said capacitance elements are located so that an electrode distance in one capacitance element increases and an electrode distance in the other capacitance element decreases when the displacement body is displaced along the detection axis.

3. An acceleration detector detecting an acceleration component along a detection axis, said detector comprising:

a fixed body and a displacement body, said displacement body being resiliently supported by said fixed body,

a first capacitance element including a first fixed electrode fixed to said fixed body and a first displacement electrode fixed to said displacement body,

a second capacitance element including a second fixed electrode fixed to said fixed body and a second displacement electrode fixed to said displacement body, and

an output unit for outputting information indicating an acceleration component along said detection axis based on a difference between a capacitance value of said first capacitance element and a capacitance value of said second capacitance element.

4. The acceleration detector as set forth in claim 3, wherein the first capacitance element and the second capacitance element are located so that a distance of electrodes in one capacitance element increases and a distance of electrodes in the other capacitance element decreases when the displacement body is displaced by applying an acceleration along the detection axis.

5. The acceleration detector as set forth in claim 3, wherein the first capacitance element and the second capacitance element are located on the detection axis.

6. An acceleration detector detecting an acceleration component along an axis, said detector comprising:

a fixed substrate and a displacement substrate, said displacement substrate being resiliently supported by said fixed substrate,

a first capacitance element including a first fixed electrode and a first displacement electrode, said first fixed electrode being supported by said fixed substrate and said first displacement electrode being supported by said displacement substrate so that said first displacement electrode is displaced with respect to said first fixed electrode when said displacement substrate is displaced with respect to said fixed substrate,

a second capacitance element including a second fixed electrode and a second displacement electrode, said second fixed electrode being supported by said fixed substrate and said second displacement electrode being supported by said displacement substrate so that said second displacement electrode is displaced with respect to said second fixed electrode when said displacement substrate is displaced with respect to said fixed substrate, and

an output unit for outputting information indicating an acceleration component along a detection axis which is perpendicular to an upper surface of said fixed substrate based on a difference between a capacitance value of said first capacitance element and a capacitance value of said second capacitance element.

7. The acceleration detector as set forth in claim 6, wherein the first capacitance element and the second capacitance element are located so that a distance of electrodes in one capacitance element increases and a distance of electrodes in the other capacitance element decreases when the displacement substrate is displaced by applying an acceleration along the detection axis.

8. The acceleration detector as set forth in claim 6, wherein the first capacitance element and the second capacitance element are located on the detection axis.