Sensor assembly having an overload stop
A sensor assembly includes a sensor and an overload stop disposed on a surface of the sensor. The sensor has a resilient central region and an outer region surrounding the central region. The overload stop includes a center stop disposed on the central region and a peripheral stop disposed on the outer region.
1. A sensor assembly, comprising:
a sensor having a resilient central region and an outer region surrounding the central region; and
an overload stop disposed on a surface of the sensor, the overload stop includes a center stop disposed on the central region and a peripheral stop disposed on the outer region.
2. The sensor assembly of claim 1 , wherein the center stop and the peripheral stop both protrude from the surface of the sensor.
3. The sensor assembly of claim 2 , wherein the center stop protrudes a first distance from the surface of the sensor and the peripheral stop protrudes a second distance from the surface of the sensor, the first distance is greater than the second distance.
4. The sensor assembly of claim 3 , wherein a difference between the first distance and the second distance is less than or equal to a maximum deflection of the central region.
5. The sensor assembly of claim 1 , wherein the center stop and the peripheral stop each have a rigidity greater than a rigidity of the central region.
6. The sensor assembly of claim 1 , wherein the center stop is fixed on the surface of the sensor at a position of maximum deflection of the central region.
7. The sensor assembly of claim 1 , wherein the sensor is a piezoresistive force sensor die.
8. A sensor package, comprising:
a sensor assembly including a sensor and an overload stop disposed on a surface of the sensor, the sensor has a resilient central region, the overload stop includes a center stop disposed on the central region; and
an actuation element movable between a first position and a second position, the actuation element urges the center stop during movement between the first position and the second position deflecting the central region in a deflection direction.
9. The sensor package of claim 8 , wherein the sensor has an outer region surrounding the central region and the overload stop further includes a peripheral stop disposed on the outer region.
10. The sensor package of claim 9 , wherein the center stop protrudes a first distance from the surface of the sensor and the peripheral stop protrudes a second distance from the surface of the sensor, the first distance is greater than the second distance.
11. The sensor package of claim 10 , wherein the second position of the actuation element corresponds to a maximum deflection of the central region, the actuation element contacts the center stop and the peripheral stop in the second position.
12. The sensor package of claim 8 , further comprising a housing containing the sensor assembly and an elastomer disposed between the sensor assembly and the housing.
13. The sensor package of claim 12 , wherein the elastomer has a conductive portion and a non-conductive portion.
14. The sensor package of claim 13 , wherein the conductive portion and the non-conductive portion of the elastomer are each formed of a biocompatible material.
15. The sensor package of claim 14 , wherein the non-conductive portion of the elastomer is formed of a polydimethylsiloxane and the conductive portion of the elastomer is formed of the polydimethylsiloxane with a conductive composite dispersed within the polydimethylsiloxane.
16. The sensor package of claim 13 , wherein the conductive portion of the elastomer electrically connects an electrical pad of the sensor with an electrical contact disposed on the housing.
17. The sensor package of claim 12 , wherein the elastomer is disposed between the surface of the sensor and the housing and between a side of the sensor and the housing.
18. The sensor package of claim 17 , wherein the elastomer is disposed between a bottom of the sensor and the housing.
19. The sensor package of claim 12 , further comprising an integrated circuit disposed within the housing and electrically connected to the sensor.
20. A method of forming a sensor assembly, comprising:
providing a sensor having a central region adapted to resiliently deflect and an outer region surrounding the central region; and
depositing an overload stop on a surface of the sensor, the overload stop includes a center stop disposed on the central region and a peripheral stop disposed on the outer region.
21. The method of claim 20 , wherein the depositing step forms each of the center stop and the peripheral stop as a plurality of film layers on the surface of the sensor.
22. The method of claim 21 , wherein the center stop protrudes a first distance from the surface of the sensor and the peripheral stop protrudes a second distance from the surface of the sensor, the first distance is greater than the second distance.