Acceleration sensor

• US 20020029637A1
• Filed: 05/25/2001
• Published: 03/14/2002
• Est. Priority Date: 12/27/1993
• Status: Active Grant

• Current Assignee: Masahiro Matsumoto, Masayuki Miki, Seikou Suzuki
• Original Assignee: Masahiro Matsumoto, Masayuki Miki, Seikou Suzuki
• Inventors: Miki, Masayuki, Suzuki, Seikou, Matsumoto, Masahiro
• Granted Patent: US 6,463,804 B2
• Time in Patent Office: Days
• US Class Current: 73/504.01
• 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 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

An acceleration sensor is disclosed which includes a capacitance-type acceleration detection element mounted on a ceramic base plate. The element comprises a movable electrode mounted between a pair of fixed electrodes. Acceleration of the sensor in a measurement direction causes the movable electrode to move relative to the fixed electrodes and the element has opposite ends in a direction perpendicular to the measurement direction. The acceleration detection element is mounted on the base at a first one of the opposite ends. Accordingly, the mounting surface of the acceleration sensor is parallel to the direction of acceleration to be detected. Thus the acceleration sensor can be surface-mounted on a printed board, and more be easily mounted in an automobile air bag control system or the like.

Claims

1. An acceleration sensor including:

a base; and

an acceleration detection element of capacitance type mounted on said base, said acceleration detection element having a movable electrode mounted adjacent a fixed electrode such that acceleration of the sensor in a measurement direction causes said movable electrode to move relative to said fixed electrode, said acceleration detection element further having opposite ends in a direction perpendicular to said measurement direction;

wherein said acceleration detection element is mounted on said base at a first one of said opposite ends.

2. An acceleration sensor according to claim 1 wherein said movable electrode is supported by a flexible beam which extends from said movable electrode towards the other one of said opposite ends.

3. An acceleration sensor according to claim 1 wherein said acceleration detection element includes at least one electrical connection terminal located at the other one of said opposite ends.

4. An acceleration sensor according to claim 1 wherein said acceleration detection element has at least one end face which is substantially parallel to the direction of acceleration detectable by motion of said movable electrode, and

wherein said acceleration detection element is mounted on said base such that said end face lies on said base.

5. An acceleration sensor according to claim 1 wherein said movable electrode is supported by a flexible beam,

said acceleration detection element having a pair of said end faces which are each substantially parallel to the direction of acceleration detectable by motion of said movable electrode, a first one of said pair of end faces being the most remote from said beam,

said element being mounted on said base such that said first end face lies on said base.

6. An acceleration sensor according to claim 1 wherein said acceleration detection element is attached to said base by elastomeric adhesive.

7. An acceleration sensor according to claim 1 wherein said base is a ceramic base and said sensor further includes signal processing means mounted on said base,

said signal processing means being electrically connected by electrical connection means to said acceleration detection element, and

said signal processing means being adapted to convert electrical information output from said acceleration detection element into an electrical signal related to acceleration detected by said acceleration detection element.

8. An acceleration sensor according to claim 7 wherein said ceramic base includes electrical tracks being part of said electrical connection means.

9. An acceleration sensor according to claim 8 wherein said electrical connection means connect said signal processing means to said movable electrode and said fixed electrode.

10. An acceleration sensor according to claim 9 wherein said acceleration detection element includes at least first and second electrical connection terminals for electrical connection to said movable electrode and said fixed electrode respectively, and said terminals are connected using solder directly to said electrical connection means on said base plate.

13. An acceleration sensor according to claim 1 wherein said movable electrode comprises a first semiconductor layer which is mounted between first and second insulating layers, there being a pair of said fixed electrodes provided respectively on faces of said first and second insulating layers adjacent said movable electrode,

said acceleration sensor further including second and third semiconductor layers each respectively mounted on a face of said first and second insulating layers remote from said movable electrode, each of said fixed electrodes being connected to a different one of said second and third semiconductor layers.

11. Electrical apparatus including an acceleration sensor, said acceleration sensor including:

a base; and

an acceleration detection element of capacitance type mounted on said base, said acceleration detection element having a movable electrode mounted adjacent a fixed electrode such that acceleration of the sensor in a measurement direction causes said movable electrode to move relative to said fixed electrode, said acceleration detection element further having opposite ends in a direction perpendicular to said measurement direction;

wherein said acceleration detection element is mounted on said base at a first one of said opposite ends;

said apparatus further including a circuit board and said acceleration sensor being mounted on said circuit board using mounting means, wherein said mounting means also provide electrical connection between said circuit board and said acceleration sensor.

12. Electrical apparatus according to claim 11 wherein said acceleration sensor is mounted on said circuit board such that said base is substantially perpendicular to said circuit board.

15. An acceleration sensor according to claim 14 wherein said acceleration detection element comprises a movable electrode mounted adjacent a fixed electrode, and said electrical connection means connect said signal processing means to said movable electrode and said fixed electrode.

16. An acceleration sensor according to claim 15 wherein said element includes first and second electrical connection terminals for electrical connection to said movable electrode and said fixed electrode respectively, and said terminals are connected using solder directly to said electrical connection means on said base.

18. Electrical apparatus according to claim 17 wherein said acceleration sensor is mounted on said circuit board such that said base is substantially perpendicular to said circuit board.

20. An air bag control system according to claim 19 including a circuit board, wherein said base is mounted on said circuit board using mounting means, said mounting means also providing electrical connection between said circuit board and said acceleration sensor.

21. An air bag control system according to claim 20 wherein said acceleration sensor is mounted on said circuit board such that said base is substantially perpendicular to said circuit board.

14. An acceleration sensor including an acceleration detection element mounted on a ceramic base, and signal processing means mounted on said base and electrically connected by electrical connection means to said acceleration detection element,

said base including electrical tracks being part of said electrical connection means,

said signal processing means being adapted to convert electrical information output from said acceleration detection element to an electrical signal related to acceleration detected by said acceleration detection element.

17. Electrical apparatus including an acceleration sensor, said acceleration sensor including an acceleration detection element mounted on a ceramic base, and signal processing means mounted on said base and electrically connected by electrical connection means to said acceleration detection element,

said base including electrical tracks being part of said electrical connection means,

said signal processing means being adapted to convert electrical information output from said acceleration detection element to an electrical signal related to acceleration detected by said acceleration detection element;

said acceleration sensor being mounted on a circuit board using mounting means, wherein said mounting means also provide electrical connection between said circuit board and said acceleration sensor.

19. An automobile air bag control system comprising an acceleration sensor including

a base, and

an acceleration detection element of capacitance type mounted on said base, said acceleration detection element having a movable electrode mounted adjacent a fixed electrode such that acceleration of the sensor in a measurement direction causes said movable electrode to move relative to said fixed electrode, said acceleration detection element further having opposite ends in a direction perpendicular to said measurement direction;

wherein said acceleration detection element is mounted on said base at a first one of said opposite ends,

said acceleration sensor further including signal processing means mounted on said base and electrically connected by electrical connection means to said acceleration detection element, said signal processing means being adapted to convert electrical information output from said acceleration detection element to an electrical signal related to acceleration detected by said acceleration detection element.

22. An acceleration sensor including a capacitance-type acceleration detection element mounted on a ceramic base plate by elastomeric adhesive,

said acceleration detection element comprising a movable electrode mounted between a pair of fixed electrodes, wherein said movable electrode is supported between the pair of fixed electrodes by a flexible beam, and the acceleration detection element has a pair of end faces which are each substantially parallel to the direction of acceleration detectable by motion of the movable electrode, a first one of said pair of end faces being the most remote from the beam,

said acceleration detection element being mounted on the base plate such that said first end face lies on the plate,

the sensor further including first, second and third electrical connection terminals for electrical connection to said movable electrode and each of said fixed electrodes respectively,

said electrical connection terminals being located on the one of said pair of end faces which does not lie on the base plate,

said sensor further including signal processing means mounted on said base plate and electrically connected by electrical connection means to said acceleration detection element, said plate including electrical tracks being part of said electrical connection means, and

said signal processing means being adapted to convert electrical information output from said acceleration detection element to an electrical signal related to acceleration detected by said acceleration detection element.