Sensor element and particle sensor
First Claim
1. A sensor element for detecting a solid particle in a fluid, comprising:
- a substrate comprising (i) a main body having a closed-bottom recess formed in an upper surface thereof, and (ii) a thin-walled vibrating portion covering said recess so as to form a closed cavity; and
a detecting unit formed on a surface of said thin-walled vibrating portion outside said closed cavity, said detecting unit comprising a piezoelectric film, a first electrode coated on at least a portion of the outer surface of said piezoelectric film, and a second electrode coated on at least a portion of the inner surface of said piezoelectric film;
wherein said detecting unit and said thin-walled vibrating portion have sufficiently low mass such that solid particles in the fluid strike said detecting unit causing said detecting unit and said thin-walled vibrating portion to vibrate, and said piezoelectric film converts the vibration into an electric signal.
3 Assignments
0 Petitions
Accused Products
Abstract
A sensor element for detecting solid particles in a fluid includes: a detecting unit including a piezoelectric film consisting essentially of a ceramic material, a first electrode coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion so that the second electrode is coated onto at least a portion of the vibrating portion; and a fixing portion for fixing the may vibrate portion so that the vibrating portion vibrates. At least one of the detecting unit and the vibrating portion contacts-with a solid particle in the fluid so that the piezoelectric film converts the vibration into an electric signal. A particle sensor includes the sensor element. The sensor element and the particle sensor are excellent in particle detection precision and durability at low cost.
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Citations
7 Claims
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1. A sensor element for detecting a solid particle in a fluid, comprising:
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a substrate comprising (i) a main body having a closed-bottom recess formed in an upper surface thereof, and (ii) a thin-walled vibrating portion covering said recess so as to form a closed cavity; and a detecting unit formed on a surface of said thin-walled vibrating portion outside said closed cavity, said detecting unit comprising a piezoelectric film, a first electrode coated on at least a portion of the outer surface of said piezoelectric film, and a second electrode coated on at least a portion of the inner surface of said piezoelectric film; wherein said detecting unit and said thin-walled vibrating portion have sufficiently low mass such that solid particles in the fluid strike said detecting unit causing said detecting unit and said thin-walled vibrating portion to vibrate, and said piezoelectric film converts the vibration into an electric signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification