Thin flexible sensor

1. A sensor ( 100 , 300 , 400 ) comprising:

a thin and substantially flat flexible substrate ( 102 , 406 );

one or more sensor arrays ( 104 , 302 ) fabricated on the flexible substrate ( 102 , 406 ) that measure acceleration, force or pressure, wherein each sensor array includes at least a pressure sensor comprising a bridge structure having a central plate suspended over a pit by at least two bridge arms and one or more piezoresistors disposed on at least one of the bridge arms;

an output interface ( 108 , 418 ) disposed on the flexible substrate ( 102 , 406 );

a processor or an analog circuit ( 304 ) disposed on the flexible substrate ( 102 , 406 ) and connected to the one or more sensor arrays ( 104 , 302 ) and the output interface ( 108 , 418 );

a power source ( 106 , 416 ) disposed on the flexible substrate ( 102 , 406 ) and connected to the one or more sensor arrays ( 104 , 302 ), the output interface ( 108 , 418 ), and the processor or the analog circuit ( 304 ); and

the flexible substrate ( 102 , 406 ), the one or more sensor arrays ( 104 , 302 ), the output interface ( 108 , 418 ), the processor or an analog circuit ( 304 ) and the power source ( 106 , 416 ) form a flexible integrated circuit that can be stretched, wrinkled or flexed without degradation of the flexible integrated circuit.

2. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein:

the flexible substrate ( 102 , 406 ) comprises a polymer or a metal film; and

the one or more sensor arrays ( 104 , 302 ) measure depth, force, frequency or acceleration of compressions.

3. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , further comprising a protective layer covering the sensor array(s) ( 104 , 302 ), the processor or the analog circuit ( 304 ), and the output interface ( 108 , 418 ).

4. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the sensor array(s) ( 104 , 302 ) comprise:

one or more accelerometers ( 200 ); and

one or more pressure sensors ( 202 ) positioned around the accelerometer(s) ( 200 ).

5. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein:

the processor or the analog circuit ( 304 ) determines whether one or more operational parameters are within one or more guidelines and provides a feedback regarding whether the operational parameters are within the guidelines via the output interface ( 108 , 418 ); and

the one or more operational parameters comprise an applied pressure, an acceleration, a shearing force, a compressive force or a combination thereof.

6. The sensor ( 100 , 300 , 400 ) as recited in claim 5 , further comprising a data storage ( 310 ) connected to the processor or the analog circuit ( 304 ) that stores the one or more parameters, the feedback, a status of the sensor, diagnostic information or a combination thereof.

7. The sensor ( 100 , 300 , 400 ) as recited in claim 6 , wherein the data storage ( 310 ) comprises a RFID tag, a magnetic strip, a memory or a combination thereof.

8. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the substrate ( 102 , 406 ) is rigid or semi-flexible instead of flexible.

9. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the sensor array(s) ( 104 , 302 ) further measure one or more operational parameters.

10. The sensor ( 100 , 300 , 400 ) as recited in claim 9 , wherein the one or more operational parameters comprise a physical contact with an object or a recipient, a temperature of the object or the recipient, an electrical activity of the object or the recipient, or a combination thereof.

11. The sensor ( 100 , 300 , 400 ) as recited in claim 10 , wherein:

the recipient is a human or an animal; and

the object is a machine, a structure, a composition, a vehicle, a plant or a natural object.

12. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the output interface ( 108 , 418 ) comprises a visual display, a speaker, a multi-tone generator, a communications interface ( 306 ) or a combination thereof.

13. The sensor ( 100 , 300 , 400 ) as recited in claim 12 , wherein the visual display comprises a set of light emitting diodes, a liquid crystal display or combination thereof that provide a feedback to a user.

14. The sensor ( 100 , 300 , 400 ) as recited in claim 12 , wherein the communications interface ( 306 ) comprises an optical communications interface, an infrared communications interface, a wireless communications transceiver, a physical communications port or a combination thereof.

15. The sensor ( 100 , 300 , 400 ) as recited in claim 14 , wherein the wireless transceiver comprises an active radio frequency identification tag, a passive radio frequency identification tag, a cellular phone, an Internet connection or a personal data assistant.

16. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , further comprising:

a geographic locator ( 208 ) that is disposed on the flexible substrate ( 102 , 406 ) and connected to the processor or the analog circuit ( 304 ); and

a communications interface ( 306 ) disposed on the flexible substrate ( 102 , 406 ), connected to the processor or the analog circuit ( 304 ), wherein the processor or the analog circuit ( 304 ) periodically transmits a status of the sensor, a location of the sensor as determined by the geographic locator ( 208 ), diagnostic information, a status of the recipient or object, or a combination thereof to another location via the communications interface ( 306 ).

17. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the sensor ( 100 , 300 , 400 ) is integrated in or attached to a recipient, an object, a device, a personal item, a clothing or a thin portable user device.

18. The sensor ( 100 , 300 , 400 ) as recited in claim 17 , wherein the device comprises a phone, a mobile communications device, a cellular phone, an audio and/or video device or a personal data assistant.

19. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the power source ( 106 , 416 ) comprises a battery, a solar panel, a layer of piezoelectric film ( 408 ) for voltage generation, an electromagnetic voltage generator, an energy harvesting device or a combination thereof.

20. The sensor ( 100 , 300 , 400 ) as recited in claim 19 , wherein the battery is replaceable or rechargeable.

21. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , wherein the power source ( 106 , 416 ) comprises:

a battery;

layer of piezoelectric film ( 408 ) or other energy harvesting methods for voltage generation; and

a power controller to manage power consumption and storage in the battery and the layer of piezoelectric film.

22. The sensor ( 100 , 300 , 400 ) as recited in claim 1 , further comprising a magnetic strip, a RFID tag, a wireless communications device or other information bearing device disposed on the exterior or interior of the sensor.

23. A sensor ( 100 , 300 , 400 ) comprising:

an upper protective layer ( 402 );

a lower protective layer ( 404 ); and

a thin and substantially flat flexible polymer or thin metal substrate ( 102 , 406 ) disposed between the upper protective layer ( 402 ) and the lower protective layer ( 404 );

one or more sensor arrays ( 104 , 302 ) fabricated on the substrate that measure acceleration, force or pressure, wherein each sensor array includes at least a pressure sensor comprising a bridge structure having a central plate suspended over a pit by at least two bridge arms and one or more piezoresistors disposed on at least one of the bridge arms;

an output interface ( 108 , 418 ) disposed on the substrate ( 102 , 406 );

a processor or an analog circuit ( 304 ) disposed on the substrate ( 102 , 406 ) and connected to the sensor array(s) ( 104 , 302 ) and the output interface ( 108 , 418 );

a power source ( 106 , 416 ) disposed on the substrate ( 102 , 406 ) and connected to the processor or the analog circuit ( 304 ); and

the upper protective layer ( 402 ), the lower protective layer ( 404 ), the flexible substrate ( 102 , 406 ), the one or more sensor arrays ( 104 , 302 ), the output interface ( 108 , 418 ), the processor or an analog circuit ( 304 ) and the power source ( 106 , 416 ) form a flexible integrated circuit that can be stretched, wrinkled or flexed without degradation of the flexible integrated circuit.

24. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein the upper protective layer ( 402 ) and the lower protective layer ( 404 ) encapsulate the substrate ( 102 , 406 ).

25. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , further comprising an energy producing layer ( 408 ) disposed between the lower protective layer ( 404 ) and the substrate ( 102 , 406 ).

26. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein the sensor array(s) ( 104 , 302 ) comprise:

one or more accelerometers ( 200 ) ; and

one or more pressure sensors ( 202 ) positioned around the accelerometer(s) ( 200 ).

27. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein:

the processor or the analog circuit ( 304 ) determines whether one or more operational parameters are within one or more guidelines and provides a feedback regarding whether the operational parameters are within the guidelines via the output interface ( 108 , 418 ); and

the one or more operational parameters comprise an applied pressure, an acceleration, a shearing force, a compressive force or a combination thereof.

28. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein the substrate ( 102 , 406 ) is rigid or semi-flexible instead of flexible.

29. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein the output interface ( 108 , 418 ) comprises a visual display, a speaker, a multi-tone generator, a communications interface or a combination thereof.

30. The sensor ( 100 , 300 , 400 ) as recited in claim 24 , further comprising:

a geographic locator ( 208 ) that is disposed on the flexible substrate ( 102 , 406 ) and connected to the processor or the analog circuit ( 304 ); and

a communications interface ( 306 ) disposed on the flexible substrate ( 102 , 406 ), connected to the processor or the analog circuit ( 304 ), wherein the processor or the analog circuit ( 304 ) periodically transmits a status of the sensor, a location of the sensor as determined by the geographic locator ( 208 ), diagnostic information, a status of a recipient or object, or a combination thereof to another location via the communications interface ( 306 ).

31. The sensor ( 100 , 300 , 400 ) as recited in claim 23 , wherein the power source ( 106 , 416 ) comprises a battery, a solar panel, a layer of piezoelectric film ( 408 ) for voltage generation, an electromagnetic voltage generator, an energy harvesting device or a combination thereof.

32. A method or manufacturing a sensor comprising the steps of:

passivating a silicon wafer;

adding a polyimide layer to the wafer;

creating one or more sensor arrays ( 104 , 302 ) on the polyimide layer using a Micro-Electro-Mechanical Systems (MEMS) process wherein the sensor array(s) ( 104 , 302 ) measure acceleration, force or pressure, wherein each sensor array includes at least a pressure sensor comprising a bridge structure having a central plate suspended over a pit by at least two bridge arms and one or more piezoresistors disposed on at least one of the bridge arms;

dicing the wafer to extract the individual dies/sensors;

printing a circuit on a flexible substrate ( 102 , 406 );

applying a paste or epoxy to the flexible substrate ( 102 , 406 ) to receive and secure the individual dies/sensors;

placing the individual dies/sensors on the flexible substrate ( 102 , 406 );

placing the flexible substrate ( 102 , 406 ) on a lower protective layer ( 404 ) containing electrical interconnects and an output interface ( 108 , 418 ) a processor or an analog circuit ( 304 ), and a power source ( 106 , 416 );

securing the flexible substrate ( 102 , 406 ) to the lower protective layer ( 404 );

placing and securing a upper protective layer ( 402 ) to the flexible substrate ( 102 , 406 ) and the lower protective layer ( 404 ) to complete assembly of the sensor; and

wherein the foregoing steps form a flexible integrated circuit that can be stretched, wrinkled or flexed without degradation of the flexible integrated circuit.

33. The method as recited in claim 32 , further comprising the step of testing the sensor ( 100 , 300 , 400 ).

34. The method as recited in claim 32 , wherein the one or more sensor arrays ( 104 , 302 ) comprises a pressure sensor and the step of creating the one or more sensor arrays ( 104 , 302 ) on the polyimide layer comprises the steps of:

depositing a layer of Si 3 N 4 on top of the polyimide layer;

patterning the layer of Si 3 N 4 using a mask to from the bridge structure;

depositing a polysilicon layer on top of the layer of Si 3 N 4 ;

patterning the polysilicon layer using a mask to form the one or more piezoresistors;

depositing a metallic layer on top of the polysilicon layer; and

patterning the metallic layer to form conductive leads for the pressure sensor.

35. The method as recited in claim 32 , wherein the polyimide layer comprises a first polyimide layer, and the step of creating the one or more sensor arrays ( 104 , 302 ) on the first polyimide layer comprises the steps of:

depositing a first layer of Si 3 N 4 on top of the first polyimide layer;

depositing a second layer of polyimide on the layer Si 3 N 4 ;

depositing a second layer of Si 3 N 4 on top of the second polyimide layer;

patterning the second layer of Si 3 N 4 using a mask to from the bridge structure;

depositing a polysilicon layer on top of the layer of Si 3 N 4 ;

patterning the polysilicon layer using a mask to form the one or more piezoresistors;

depositing a metallic layer on top of the polysilicon layer;

patterning the metallic layer to form conductive leads for the pressure sensor; and

underetching the second polyimide layer.

36. The method as recited in claim 32 , wherein the one or more sensor arrays ( 104 , 302 ) further includes an accelerometer, the polyimide layer comprises a first polyimide layer, and the step of creating the one or more sensor arrays ( 104 , 302 ) on the first polyimide layer comprises the steps of:

depositing a first layer of Si 3 N 4 on top of the first polyimide layer;

depositing a metallic layer on top of the first layer of Si 3 N 4 ;

patterning the metallic layer to form conductive leads for the accelerometer;

depositing a second layer of polyimide on the patterned metallic layer;

patterning the second layer of polyimide using a first mask to from one or more anchors;

depositing a second layer of Si 3 N 4 on top of the second polyimide layer;

patterning the second layer of Si 3 N 4 using a second mask to form the accelerometer; and

underetching the second polyimide layer.

37. The method as recited in claim 32 , further comprising wherein the one or more sensor arrays ( 104 , 302 ) further includes an accelerometer, the polyimide layer comprises a first polyimide layer, and the step of creating the one or more sensor arrays ( 104 , 302 ) on the first polyimide layer comprises the steps of:

depositing a first layer of Si 3 N 4 on top of the first polyimide layer;

depositing a metallic layer on top of the first layer of Si 3 N 4 ;

patterning the metallic layer to form conductive leads for the accelerometer;

depositing a second layer of polyimide on the patterned metallic layer;

patterning the second layer of polyimide using a first mask to from one or more anchors;

depositing a second layer of Si 3 N 4 on top of the second polyimide layer;

patterning the second layer of Si 3 N 4 using a second mask to form the accelerometer;

depositing a third layer of polyimide on the patterned second layer of Si 3 N 4 ;

patterning the third layer of polyimide using a third mask;

depositing an encapsulant material on the patterned third layer of polyimide;

patterning the encapsulant material using a fourth mask; and

underetching the second polyimide layer and the third polyimide layer.

38. The sensor as recited in claim 1 , wherein the sensor has a thickness less than or equal to 1.25 mm.

39. The sensor as recited in claim 23 , wherein the sensor has a thickness less than or equal to 1.25 mm.

40. The method as recited in claim 32 , wherein the sensor has a thickness less than or equal to 1.25 mm.

41. The sensor as recited in claim 1 , wherein the central shuttle plate comprises Si 3 N 4 and the pit comprises an undercut etched pit.

42. The sensor as recited in claim 23 , wherein the central shuttle plate comprises Si 3 N 4 and the pit comprises an undercut etched pit.