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US 2006/0130581 A1Published application
Acceleration sensor
AssigneeOki Electric Industry Co., Ltd.
InventorHironari Mori
Life of this patent
Estimating the term…
Abstract
The piezo-resistance type triaxial acceleration sensor includes a frame section, a mass section disposed in the frame section, beam elements which flexibly support the mass section, and piezo-resistors for the X, Y and Z axes formed on the beam elements. The length of the Z-axis piezo-resistors is longer than the length of the X-axis piezo-resistors and the Y-axis piezo-resistors, so as to decrease the sensitivity.
Claims14
An acceleration sensor, comprising:
- a frame section having an X axis, a Y axis and a Z axis of three-dimensional coordinate;
- a mass section disposed inside the frame section;
- a beam section including a plurality of X-direction beam elements extending in an X axis direction and a plurality of Y-direction beam elements extending in a Y axis direction, for flexibly connecting the mass section to the frame section by the plurality of X-direction beam elements and the plurality of Y-direction beam elements;
- a plurality of X-axis piezo-resistor pairs associated with the plurality of X-direction beam elements, respectively, each said X-axis piezo-resistor pair including a first X-axis piezo-resistor with a first length disposed in contact with one end of the associated X-direction beam element, and a second X-axis piezo-resistor with the first length disposed in contact with the other end of the associated X-direction beam element;
- a plurality of Y-axis piezo-resistor pairs associated with the plurality of Y-direction beam elements, respectively, each said Y-axis piezo-resistor pair including a first Y-axis piezo-resistor with the first length disposed in contact with one end of the associated Y-direction beam element, and a second Y-axis piezo-resistor with the first length disposed in contact with the other end of the associated Y-direction beam element;
- and
- a plurality of Z-axis piezo-resistor pairs associated with the plurality of X-axis piezo-resistor pairs, respectively, each said Z-axis piezo-resistor pair including a first Z-axis piezo-resistor with a second length disposed in the vicinity of the first X-axis piezo-resistor of the associated X-axis piezo-resistor pair, and a second Z-axis piezo-resistor with the second length disposed in the vicinity of the second X-axis piezo-resistor of the associated X-axis piezo-resistor pair, the second length being greater than the first length.
4 more elements
An acceleration sensor, comprising:
- a frame section having an X axis, a Y axis and a Z axis of three-dimensional coordinate;
- a mass section disposed inside the frame section;
- a beam section including a plurality of X-direction beam elements extending in an X axis direction and a plurality of Y-direction beam elements extending in a Y axis direction, for flexibly connecting the mass section to the frame section by the plurality of X-direction beam elements and the plurality of Y-direction beam elements;
- a plurality of X-axis piezo-resistor pairs associated with the plurality of X-direction beam elements, respectively, each said X-axis piezo-resistor pair including a first X-axis piezo-resistor with a first length disposed in contact with one end of the associated X-direction beam element, and a second X-axis piezo-resistor with the first length disposed in contact with the other end of the associated X-direction beam element;
- a plurality of Y-axis piezo-resistor pairs associated with the plurality of Y-direction beam elements, respectively, each said Y-axis piezo-resistor pair including a first Y-axis piezo-resistor with the first length disposed in contact with one end of the associated Y-direction beam element and a second Y-axis piezo-resistor with the first length disposed in contact with the other end of the associated Y-direction beam element;
- and
- a plurality of Z-axis piezo-resistor pairs associated with the plurality of X-axis piezo-resistor pairs, respectively, each said Z-axis piezo-resistor pair including a first Z-axis piezo-resistor with a second length disposed in the vicinity of the first X-axis piezo-resistor of the associated X-axis piezo-resistor pair, and a second Z-axis piezo-resistor with the second length disposed in the vicinity of the second X-axis piezo-resistor of the associated X-axis piezo-resistor pair, wherein
- said first Z-axis piezo-resistor of each said Z-axis piezo-resistor pair extends in exactly the same area as the first X-axis piezo-resistor of the associated X-axis piezo-resistor pair, and also extends in an area of smaller distortion so that the first Z-axis piezo-resistor is longer than the first X-axis piezo-resistor, and the second Z-axis piezo-resistor of each said Z-axis piezo-resistor pair extends in exactly the same area as the second X-axis piezo-resistor of the associated X-axis piezo-resistor pair and also extends in an area of smaller distortion so that the second Z-axis piezo-resistor is longer than the second X-axis piezo-resistor.
5 more elements
Dependencies are inferred from the claim text.