Acceleration sensor

Claim 2

The acceleration sensor according to claim 1, wherein said signal processing means comprises impedance converting means (22) electrically connected to the piezoelectric element (21) and for converting the impedance of the signal outputted from the piezoelectric element (21), filtering means (23) electrically connected to the impedance converting means (22) and for removing an unnecessary signal component, and amplifying means (24) electrically connected to said filtering means (23) and for amplifying a signal applied from the filtering means (23).

Claim 3

The acceleration sensor according to claim 1, wherein at least a part of said signal processing means (22-24) is constituted by a single electronic component (54) having a flat upper surface, said piezoelectric element (21) being fixed to said upper surface of said electronic component (54) in a cantilevered shape.

Claim 4

The acceleration sensor according to claim 1, which further comprises a temperature compensating capacitor (72) arranged in close proximity to said piezoelectric element (21) and connected in parallel to the piezoelectric element (21).

Claim 5

The acceleration sensor according to claim 1, wherein at least a part of said signal processing means (22-24) is constituted by a single electronic component (54), and which further comprises a base plate (52) for supporting said electronic component (54), a cushioning member for absorbing a thermal shock produced between the base plate and said electronic component due to the difference in coefficient of thermal expansion or modulus of elasticity being arranged between the base plate (52) and the electronic component (54).

Claim 6

An acceleration sensor comprising: an acceleration detecting portion (32) comprising a piezoelectric element (31) having electrodes (31a-31b) on both its surfaces and outputting a signal corresponding to acceleration applied and a supporting base for supporting said piezoelectric element (31), said acceleration detecting portion (32) being provided with a pair of detecting portions (34a, 34b) arranged so as to be brought into contact with said piezoelectric element (31) and spaced apart from each other by a predetermined distance; signal processing means (36) electrically connected to one of the electrodes (31b) of said piezoelectric (31) element and for processing the electric signal outputted from the piezoelectric element (31); and signal outputting means (35) electrically connected to one (34a) of said pair of detecting portions (34a,34b) so as to cause a predetermined current to flow between said detecting portions and connected to said signal processing means (36) so as to output to the signal processing means (36) a state signal representing the state of the acceleration detecting portion (32), said signal outputting means (35) outputting said state signal in conformity with the variation of the current flowing between the detecting portions (34a,34b).

Claim 7

The acceleration sensor according to claim 6, wherein said pair of detecting portions (34a,34b) is provided between said piezoelectric element (31) and the supporting base (32).

Claim 8

The acceleration sensor according to claim 7, wherein said supporting base is constituted by a pair of supporting members (33a,33b) arranged spaced apart from each other by a predetermined distance, an electrode constituting said pair of detecting portions 34a,34b) being formed on the upper surface of said pair of supporting members (33a,33b).

Claim 9

The acceleration sensor according to claim 8, wherein said pair of supporting members (33a,33b) is arranged so as to support the piezoelectric element (31) in both ends of the piezoelectric element (31) or in the vicinity thereof.

Claim 10

The acceleration sensor according to claim 7, wherein said supporting base (33) is arranged so as to support the piezoelectric element (31) in one end of the piezoelectric element (31) or in the vicinity thereof, a pair of electrodes constituting said pair of detecting portions (34a,34b) arranged spaced apart from each other by a predetermined distance being formed on the upper surface of said supporting base (33).

Claim 11

The acceleration sensor according to claim 6, wherein said signal processing means (36) comprises impedance converting means (37) electrically connected to the piezoelectric element (31) and for converting the impedance of the signal outputted from the piezoelectric element (31), filtering means (38) electrically connected to the impedance converting means (37) and for removing an unnecessary signal component, and amplifying means (39) electrically connected to said filtering means (38) and for amplifying a signal applied from the filtering means (38).

Claim 12

The acceleration sensor according to claim 6, wherein at least a part of said signal processing means (36) is constituted by a single electronic component (54) having a flat upper surface, said piezoelectric element (31) being fixed to said upper surface of said electronic component (54) in a cantilevered shape.

Claim 13

The acceleration sensor according to claim 6, which further comprises a temperature compensating capacitor (72) arranged in close proximity to said piezoelectric element (31) and connected in parallel to the piezoelectric element (31).

Claim 14

The acceleration sensor according to claim 6, wherein at least a part of said signal processing means (36)is constituted by a single electronic component (54), and which further comprises a base plate (52) for supporting said electronic component (54), a cushioning member for absorbing a thermal shock produced between the base plate (52) and said electronic component (54) due to the difference in coefficient of thermal expansion or modulus of elasticity being arranged between the base plate (52) and the electronic component (54).

Claim 15

An acceleration sensor comprising: a piezoelectric element (21,31) outputting an electric signal corresponding to acceleration applied; and signal processing means (22-24;36) electrically connected to said piezoelectric element (21;31) and for processing the output signal of the piezoelectric element (21; 31), an electronic component (54) constituting at least a part of said signal processing means having a flat upper surface, said piezoelectric element (21;31) being fixed to the upper surface in a cantilevered shape.

Claim 16

The acceleration sensor according to claim 15, which further comprises a package structure for containing said electronic component (54) and the piezoelectric element (21;31), said package structure comprising a base plate (52) and a cap (53) secured to the base plate (52), said electronic component (54) being secured on said base plate (52).

Claim 17

The acceleration sensor according to claim 15, wherein said electronic component (54) has an electrode (54e) electrically connected to the piezoelectric element (21;31) on its upper surface, said piezoelectric element (21;31) being secured to the upper surface of said electronic component (54) and is electrically connected to said electrode (54e).

Claim 18

The acceleration sensor according to claim 15, which further comprises a temperature compensating capacitor arranged in close proximity to said piezoelectric element and connected in parallel to the piezoelectric element.

Claim 19

The acceleration sensor according to claim 15, wherein at least a part of said signal processing means is constituted by a single electronic component (54), and which further comprises a base plate (52) for supporting said electronic component (54), a cushioning member for absorbing a thermal shock produced between the base plate (52) and said electronic component (54) due to the difference in coefficient of thermal expansion or modulus of elasticity being arranged between the base plate (52) and the electronic component (54).