Load cell
First Claim
1. A semiconductor mechano-electrical converter comprising:
- a semiconductor diaphragm having first and second principal surfaces, one of said first and second principal surfaces being substantially flat, said semiconductor diaphragm including a first thick portion, a thin portion disposed at least partially around an outer periphery of said first thick portion and having at least two piezo-resistors formed therein to constitute at least part of a bridge circuit, and a second thick portion disposed around an outer pheriphery of said thin portion; and
load applying means for applying a load selectively across one of said first and second principal surfaces at said first thick portion and across the other of said first and second principal surfaces at said second thick portion, said load applying means including a first block secured to said first thick portion and a second block secured to said second thick portion, said first and second blocks being formed of one material selected from a group consisting of boro-silicate glass and silicon, and said semiconductor diaphragm being formed of an n-type silicon wafer incorporating said piezo-resistors of a p-conductivity type.
1 Assignment
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Accused Products
Abstract
A load cell comprises a semiconductor diaphragm which includes an outer flange portion, a central rigid portion having a smaller thickness than the outer flange portion and a thin resilient portion provided between the outer flange portion and the central rigid portion. At least two piezo-resistors constituting at least part of a bridge circuit are formed in the resilient portion. The load cell further comprises a first glass block secured to the central rigid portion, and a second glass block for securing the outer flange portion. A load is applied to the semiconductor diaphragm through the first glass block, wherein measurement of the applied load is effected by detecting variation in resistance of the resistor bridge circuit.
105 Citations
15 Claims
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1. A semiconductor mechano-electrical converter comprising:
- a semiconductor diaphragm having first and second principal surfaces, one of said first and second principal surfaces being substantially flat, said semiconductor diaphragm including a first thick portion, a thin portion disposed at least partially around an outer periphery of said first thick portion and having at least two piezo-resistors formed therein to constitute at least part of a bridge circuit, and a second thick portion disposed around an outer pheriphery of said thin portion; and
load applying means for applying a load selectively across one of said first and second principal surfaces at said first thick portion and across the other of said first and second principal surfaces at said second thick portion, said load applying means including a first block secured to said first thick portion and a second block secured to said second thick portion, said first and second blocks being formed of one material selected from a group consisting of boro-silicate glass and silicon, and said semiconductor diaphragm being formed of an n-type silicon wafer incorporating said piezo-resistors of a p-conductivity type. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a semiconductor diaphragm having first and second principal surfaces, one of said first and second principal surfaces being substantially flat, said semiconductor diaphragm including a first thick portion, a thin portion disposed at least partially around an outer periphery of said first thick portion and having at least two piezo-resistors formed therein to constitute at least part of a bridge circuit, and a second thick portion disposed around an outer pheriphery of said thin portion; and
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13. A load cell comprising:
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an n-type silicon wafer semiconductor diaphragm including a thick central portion having a first flat surface, a second thick flange portion disposed to enclose said central portion and having a second flat surface at the side opposite to said first flat surface, and a thin resilient portion for connecting said central portion and said flange portion to each other and having p-conductivity type piezo-resistor elements formed therein; a first rigid body secured to said first surface of said central portion; a second rigid body secured to said second surface of said flange portion, said first and second rigid bodies being formed of one material selected from the group consisting of boro-silicate glass and silicon; and a case accommodating said semiconductor diaphragm, and said first and second rigid bodies in such a manner that a relative movement is allowed between said first and second rigid bodies. - View Dependent Claims (14, 15)
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Specification