Conductive stiffener, method of making a conductive stiffener, and conductive adhesive and encapsulation layers

• US 10,653,332 B2
• Filed: 07/12/2016
• Issued: 05/19/2020
• Est. Priority Date: 07/17/2015
• Status: Active Grant

• Current Assignee: Medidata Solutions Incorporated (Dassault Systemes SA)
• Original Assignee: MC10, Inc.
• Inventors: McGrane, Bryan, Raj, Milan, Wei, PingHung, Morey, Briana, Ghaffari, Roozbeh, Lin, Monica, Model, Jeffrey, Wang, Xianyan, Keen, Bryan, Lee, Stephen
• Primary Examiner(s): Milakovich, Nathan
• Application Number:
  US15/208,444
• Publication Number:
  US 20170019988A1
• Time in Patent Office: 1,407 Days
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 2562/166 the sensor is mounted on a specially adapted printed circuit board
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/296 for electromyography [EMG]
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/398 Electrooculography [EOG], e.g. detecting nystagmus; Electroretinography [ERG]
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: H05K 1/0209 External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/0969 Apertured conductors
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 2201/10401 Eyelets, i.e. rings inserted into a hole through a circuit board
• CPC Class Codes: H05K 2201/2009 Reinforced areas, e.g. for a specific part of a flexible printed circuit
• CPC Class Codes: H05K 2203/1327 : Moulding over PCB locally or completely applying non-metallic protective coatings for encapsulating mounted components H05K3/284

Abstract

A device includes a flexible printed circuit board and one or more conductive stiffeners. The conductive stiffeners include a conductive surface that can be electrically connected to contact pads on the flexible printed circuit board. The wearable device can further include an adhesive layer or an encapsulation layer. The adhesive layer and the encapsulation layer can include conductive portions surrounded by non-conductive portions. The conductive portions can be aligned with the conductive stiffeners and together transmit electrical energy to the contact pads of the flexible printed circuit board.

Claims

1. A device comprising:

a flexible printed circuit board having a plurality of discrete operative devices electrically interconnected and one or more contact pads on a backside of the flexible printed circuit board; and

a plurality of conductive stiffeners affixed to the backside of the flexible printed circuit board, each conductive stiffener electrically connecting at least one contact pad of the flexible printed circuit board to a bottom surface of the conductive stiffener and comprising;

a non-conductive substrate sheet;

a hole through the non-conductive substrate sheet; and

a conductive material forming a pad on a bottom surface of the non-conductive substrate sheet and lining the hole, wherein the pad of conductive material is electrically connected to a top surface of the non-conductive substrate sheet through the conductive material lining the hole,

wherein the conductive material forms a pad on the top surface of the non-conductive substrate sheet, and the pad of conductive material on the top surface comprises a thermal relief pattern in the conductive material surrounding the hole.

2. The device of claim 1, further comprising an encapsulation layer encapsulating the flexible printed circuit board and the plurality of conductive stiffeners.

3. The device of claim 2, wherein the encapsulation layer comprises non-conductive areas surrounding conductive areas, and the conductive areas are aligned with the bottom surfaces of the conductive stiffeners.

4. The device of claim 2, wherein a bottom surface of each conductive stiffener includes one or more indentations that interface with the encapsulation layer to mechanically couple the encapsulation layer to the plurality of conductive stiffeners.

5. The device of claim 4, wherein the one or more indentations are vertical interconnects accesses.

6. The device of claim 2, wherein a bottom surface of the flexible printed circuit board includes one or more indentations that interface with the encapsulation layer to mechanically couple the encapsulation layer to the flexible printed circuit board.

7. The device of claim 2, wherein at least one end of the flexible printed circuit board is folded creating a pocket, and the pocket is filled with encapsulation material forming the encapsulation layer to mechanically couple the encapsulation layer to the flexible printed circuit board.

8. The device of claim 7, wherein the at least one end of the flexible printed circuit board includes one or more vertical interconnect accesses, and the encapsulation material fills the one or more vertical interconnect accesses from the pocket through the at least one end to mechanically couple the encapsulation layer to the flexible printed circuit board.

9. The device of claim 1, wherein each of the conductive stiffeners includes a vertical interconnect access (VIA) through which the conductive stiffeners attach to the corresponding discrete operative device.

10. The device of claim 1, wherein the non-conductive substrate sheet is comprised of at least two FR-4 glass-reinforced epoxy laminate sheets.

11. The device of claim 10, wherein each sheet of the at least two sheets is 0.002 inches thick.

12. The device of claim 10, wherein the at least two sheets are adhered together with an adhesive layer.

13. The device of claim 12, wherein the adhesive layer is 0.002 inches thick.

14. The device of claim 1, wherein the conductive material is selected from a group consisting of copper, tin, nickel, silver, and gold.

15. The device of claim 1, wherein the pad of conductive material on the bottom surface is 0.0014 inches thick.

16. The device of claim 1, wherein the pad of conductive material on the top surface is 0.0014 inches thick.

17. A device comprising:

a flexible printed circuit board having a plurality of discrete operative devices electrically interconnected and one or more contact pads on a backside of the flexible printed circuit board; and

a plurality of conductive stiffeners affixed to the backside of the flexible printed circuit board, each conductive stiffener electrically connecting at least one contact pad of the flexible printed circuit board to a bottom surface of the conductive stiffener and comprising;

a non-conductive substrate sheet;

a hole through the non-conductive substrate sheet; and

a conductive material forming a pad on a bottom surface of the non-conductive substrate sheet and lining the hole, wherein the pad of conductive material is electrically connected to a top surface of the non-conductive substrate sheet through the conductive material lining the hole,

wherein the conductive material forms a pad on the top surface of the non-conductive substrate sheet, and the pad of conductive material on the top surface is 0.0014 inches thick.

18. The device of claim 17, further comprising an encapsulation layer encapsulating the flexible printed circuit board and the plurality of conductive stiffeners.

19. The device of claim 18, wherein the encapsulation layer comprises non-conductive areas surrounding conductive areas, and the conductive areas are aligned with the bottom surfaces of the conductive stiffeners.

20. The device of claim 18, wherein a bottom surface of each conductive stiffener includes one or more indentations that interface with the encapsulation layer to mechanically couple the encapsulation layer to the plurality of conductive stiffeners.

21. The device of claim 20, wherein the one or more indentations are vertical interconnects accesses.

22. The device of claim 21, wherein a bottom surface of the flexible printed circuit board includes one or more indentations that interface with the encapsulation layer to mechanically couple the encapsulation layer to the flexible printed circuit board.

23. The device of claim 18, wherein at least one end of the flexible printed circuit board is folded creating a pocket, and the pocket is filled with encapsulation material forming the encapsulation layer to mechanically couple the encapsulation layer to the flexible printed circuit board.

24. The device of claim 23, wherein the at least one end of the flexible printed circuit board includes one or more vertical interconnect accesses, and the encapsulation material fills the one or more vertical interconnect accesses from the pocket through the at least one end to mechanically couple the encapsulation layer to the flexible printed circuit board.

25. The device of claim 17, wherein each of the conductive stiffeners includes a vertical interconnect access (VIA) through which the conductive stiffeners attach to the corresponding discrete operative device.

26. The device of claim 17, wherein the non-conductive substrate sheet is comprised of at least two FR-4 glass-reinforced epoxy laminate sheets.

27. The device of claim 26, wherein each sheet of the at least two sheets is 0.002 inches thick.

28. The device of claim 26, wherein the at least two sheets are adhered together with an adhesive layer.

29. The device of claim 28, wherein the adhesive layer is 0.002 inches thick.

30. The device of claim 17, wherein the conductive material is selected from a group consisting of copper, tin, nickel, silver, and gold.

31. The device of claim 17, wherein the pad of conductive material on the bottom surface is 0.0014 inches thick.