Acceleration sensor
First Claim
1. An acceleration sensor comprising:
- a first substrate formed of a silicon material which is used as a conductive material;
a second substrate provided on the lower side of said first substrate and electrically insulated from the first substrate;
said first substrate including;
a support beam having a mass portion forming capacitive electrodes for displacement in a parallel direction to a surface of said second substrate according to the degree of acceleration, a fixed portion for fixing said support beam to said second substrate and a support portion for intermediately supporting said mass portion to said fixed portion,an insulating groove extending through a thickness of said first substrate around the entire periphery of said support beam, and stationary blocks forming capacitive electrodes defined by said insulating groove on the outer sides of said support beam separately across said insulating groove and fixed to said second substrate;
gap means forming a gap space in order to space said mass portion and said support portion from a surface of said second substrate; and
said second substrate being separated from said first substrate by an insulating layer which is at least provided on the lower side of said fixed portion and stationary blocks.
1 Assignment
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Accused Products
Abstract
An acceleration sensor having movable and stationary electrodes electrically insulated from each other in a reliable manner to improve the accuracy and sensitivity in the detection of acceleration. The acceleration sensor includes an upper substrate (1) of a low resistivity silicon material, a lower substrate (2) of an insulating material provided under the upper substrate (1), and an insulating groove (5) perforating the upper substrate (1) completely from the upper to lower side thereof and around the entire periphery of a support beam (4) in the upper substrate (1). By using the upper substrate (1), stationary blocks (6) are formed separately on the opposite sides of the support beam (4) in confronting relation therewith. As a result, the support beam (4) and the stationary blocks (6), each being formed of the same low resistance material, are electrically insulated from each other by the insulating groove (5). An acceleration signal is produced on the basis of a variation in electrostatic capacitance across movable and stationary electrodes, which are constituted by a mass portion (4C) of the support beam (4) and each of the stationary blocks (6).
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Citations
20 Claims
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1. An acceleration sensor comprising:
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a first substrate formed of a silicon material which is used as a conductive material; a second substrate provided on the lower side of said first substrate and electrically insulated from the first substrate; said first substrate including; a support beam having a mass portion forming capacitive electrodes for displacement in a parallel direction to a surface of said second substrate according to the degree of acceleration, a fixed portion for fixing said support beam to said second substrate and a support portion for intermediately supporting said mass portion to said fixed portion, an insulating groove extending through a thickness of said first substrate around the entire periphery of said support beam, and stationary blocks forming capacitive electrodes defined by said insulating groove on the outer sides of said support beam separately across said insulating groove and fixed to said second substrate; gap means forming a gap space in order to space said mass portion and said support portion from a surface of said second substrate; and said second substrate being separated from said first substrate by an insulating layer which is at least provided on the lower side of said fixed portion and stationary blocks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An acceleration sensor comprising:
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a substrate which is selected from the group consisting of an insulating material and oxidized semiconductor material; a support beam which includes a mass portion forming a predetermined mass and first capacitive electrodes on side surfaces of said mass portion, a fixed portion for fixing said support beam to said substrate and a thin support portion for intermediately connecting between said mass portion and said fixed portion; a pair of stationary blocks arranged on both sides of said support beam separately across an air gap and fixed to said substrate, said stationary blocks provided with second capacitive electrodes on the opposite sides of first capacitive electrodes of said mass portion; gap means forming a gap space in order to space said mass portion and thin support portion from a surface of said substrate; and said mass portion being displaced in a parallel direction to the surface of said substrate according to the degree of acceleration and said support beam and stationary blocks formed of a silicon material which is used as a conductive material and electrically insulated from said substrate. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification