Connection for flex circuit and rigid circuit board

• US 7,448,923 B2
• Filed: 11/22/2006
• Issued: 11/11/2008
• Est. Priority Date: 09/14/2006
• Status: Expired due to Fees

• Current Assignee: Harshad K. Uka
• Original Assignee: Harshad K. Uka
• Inventors: Uka, Harshad K
• Primary Examiner(s): Luebke; Renee S
• Assistant Examiner(s): Patel; Harshad C
• Application Number:
  US11/562,905
• Publication Number:
  US 20080139011A1
• Time in Patent Office: 720 Days
• Field of Search: 439/67, 439/83, 439/74, 439/64, 439/876, 439/721, 439/904, 439/75, 361/742, 361/804, 361/758, 174/88.R
• US Class Current: 439/876
• CPC Class Codes: H01R 12/62 connecting to rigid printed circuits or like structures
• CPC Class Codes: H01R 4/024 comprising preapplied solder
• CPC Class Codes: H01R 43/0235 for applying solder H01R43/0228 takes precedence
• CPC Class Codes: H01R 43/0249 for simultaneous welding or soldering of a plurality of wires to contact elements
• CPC Class Codes: H01R 43/0256 for soldering or welding connectors to a printed circuit board
• CPC Class Codes: H05K 2201/09036 Recesses or grooves in insulating substrate
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/10666 Plated through-hole for surface mounting on PCB
• CPC Class Codes: H05K 2201/2036 Permanent spacer or stand-off in a printed circuit or printed circuit assembly
• CPC Class Codes: H05K 2203/063 of preperforated insulating layer
• CPC Class Codes: H05K 2203/1178 Means for venting or for letting gases escape
• CPC Class Codes: H05K 3/363 by soldering

Abstract

Conductive pads of a flex circuit may be electrically connected to conductive pads of a rigid circuit board. The conductive pads of the flex circuit may be sized, configured and alignable to the conductive pads of the rigid circuit board. A spacer with a plurality of apertures may be sized, configured and aligned to the conductive pads of the flex circuit and the rigid circuit board. Solder paste may be disposed between respective conductive pads of the flex circuit and the rigid circuit board within the apertures of the spacer. When the flex circuit, rigid circuit board and the spacer are assembled, the solder paste is displaced through relief vents formed through the conductive pads of the flex circuit, rigid circuit board or both the flex circuit or rigid circuit board. The solder paste is reflowed and forms a rivet structure attaching the flex circuit to the rigid circuit board as well as providing an electrical connection between the conductive pads of the flex circuit and the rigid circuit board.

Claims

1. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad, a relief vent formed through the first circuit conductive pad extending between the first and second surfaces of the first circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture alignable to the relief vent of the first circuit;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit, the relief vent of the second circuit being alignable to the aperture of the spacer;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vents of the first and second circuits;

wherein the first circuit is a flex circuit and the second circuit is a rigid circuit board.

2. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad, a relief vent formed through the first circuit conductive pad extending between the first and second surfaces of the first circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture alignable to the relief vent of the first circuit;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit, the relief vent of the second circuit being alignable to the aperture of the spacer;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vents of the first and second circuits;

wherein the first and second circuits are flex circuits.

3. The interconnection of claim 2 wherein the first circuit is an upper circuit, and the second circuit is a lower circuit, and solder paste is displaced through the relief vents of the upper and lower circuits and disposed above the upper circuit and below the lower circuit.

4. The interconnection of claim 2 wherein the spacer and the first circuit are integrally formed of a unitary material.

5. The interconnection of claim 2 wherein the spacer and the second circuit are integrally formed of a unitary material.

6. The interconnection of claim 2 wherein the aperture of the spacer is larger than the relief vents of the first and second circuits, the solder paste is physically disposed between the second surface of the first circuit and the first surface of the second circuit.

7. The interconnection of claim 6 wherein an inner periphery of the spacer circumscribes an outer periphery of the conductive pad.

8. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture aligned to the relief vent of the second circuit;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vent of the second circuit;

wherein the first circuit is a flex circuit and the second circuit is a rigid circuit board.

9. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture aligned to the relief vent of the second circuit;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vent of the second circuit;

wherein the first and second circuits are flex circuits.

10. The interconnection of claim 9 wherein the first circuit is an upper circuit, the second circuit is a lower circuit, and solder paste is displaced through the relief vent of the lower circuit and disposed below the lower circuit.

11. The interconnection of claim 9 wherein the spacer and the first circuit are integrally formed of a unitary material.

12. The interconnection of claim 9 wherein the spacer and the second circuit are integrally formed of a unitary material.

13. An interconnection between circuits, the interconnection comprising:

a lower circuit defining a lower surface and an upper surface, the lower circuit having at least one conductive pad;

an upper circuit defining a lower surface and an upper surface, the upper circuit having at least one conductive pad, a relief vent formed through the upper circuit conductive pad extending between the upper and lower surfaces of the upper circuit;

a spacer defining upper and lower surfaces, the spacer having at least one aperture aligned to the relief vent of the upper circuit;

solder paste disposed within the aperture of the spacer and between the upper and lower circuits, the solder paste disposed within the relief vent of the upper circuit;

wherein the upper circuit is a flex circuit and the lower circuit is a rigid circuit board.

14. An interconnection between circuits, the interconnection comprising:

a lower circuit defining a lower surface and an upper surface, the lower circuit having at least one conductive pad;

an upper circuit defining a lower surface and an upper surface, the upper circuit having at least one conductive pad, a relief vent formed through the upper circuit conductive pad extending between the upper and lower surfaces of the upper circuit;

a spacer defining upper and lower surfaces, the spacer having at least one aperture aligned to the relief vent of the upper circuit;

solder paste disposed within the aperture of the spacer and between the upper and lower circuits, the solder paste disposed within the relief vent of the upper circuit;

wherein the upper and lower circuits are flex circuits.

15. The interconnection of claim 14 wherein solder paste is displaced through the relief vent of the upper circuit and disposed above the upper circuit.

16. The interconnection of claim 14 wherein the spacer and the upper circuit are integrally formed of a unitary material.

17. The interconnection of claim 14 wherein the spacer and the lower circuit are integrally formed of a unitary material.

18. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad, a relief vent formed through the first circuit conductive pad extending between the first and second surfaces of the first circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture alignable to the relief vent of the first circuit;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit, the relief vent of the second circuit being alignable to the aperture of the spacer;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vents of the first and second circuits;

wherein only the solder paste is disposed within the relief vents.

19. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad, a relief vent formed through the first circuit conductive pad extending between the first and second surfaces of the first circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture alignable to the relief vent of the first circuit;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit, the relief vent of the second circuit being alignable to the aperture of the spacer;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vents of the first and second circuits;

wherein the solder paste disposed above and below the first and second circuits form rivet heads.

20. An interconnection between circuits, the interconnection comprising:

a first circuit defining a first surface and a second surface, the first circuit having at least one conductive pad, a relief vent formed through the first circuit conductive pad extending between the first and second surfaces of the first circuit;

a spacer defining first and second surfaces, the spacer having at least one aperture alignable to the relief vent of the first circuit;

a second circuit defining a first surface and a second surface, the second circuit having at least one conductive pad, a relief vent formed through the second circuit conductive pad extending between the first and second surfaces of the second circuit, the relief vent of the second circuit being alignable to the aperture of the spacer;

solder paste disposed within the aperture of the spacer and between the first and second circuits, the solder paste disposed within the relief vents of the first and second circuits;

wherein the conductive pads of the first and second circuits are formed on end portions of the first and second circuits, the first and second circuits overlapping in contact with one another only at the end portions of the first and second circuits.

21. A method of interconnecting first and second circuits, the method comprising the steps of:

placing a spacer on a first circuit;

aligning a relief vent of a second circuit to an aperture of the spacer;

disposing solder paste within the aperture of the spacer;

stacking the second circuit on the spacer and the first circuit;

during the stacking step, displacing the solder paste through the relief vent and out of the relief vent external to the second circuit to form a rivet head.

22. The method of claim 21 wherein the displacing step includes pushing the solder paste out of the relief vent due to stacking the second circuit on the spacer and the first circuit.

23. The method of claim 21 further comprising the step of:

during the stacking step, displacing the solder paste through a relief vent formed in the first circuit and out of the relief vent external to the first circuit to form a rivet head.