Rip stop on flex and rigid flex circuits

• US 10,015,880 B1
• Filed: 12/09/2014
• Issued: 07/03/2018
• Est. Priority Date: 12/09/2013
• Status: Active Grant

• Current Assignee: Multek Technologies Limited
• Original Assignee: Multek Technologies Limited
• Inventors: Bergman, Mark, Vrtis, Joan K.
• Primary Examiner(s): Mayo, III, William H
• Assistant Examiner(s): Gonzalez, Hiram E
• Application Number:
  US14/565,227
• Time in Patent Office: 1,302 Days
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/0278 Rigid circuit boards or rigid supports of circuit boards locally made bendable, e.g. by removal or replacement of material
• CPC Class Codes: H05K 1/028 Bending or folding regions of flexible printed circuits H05K1/0283 takes precedence
• CPC Class Codes: H05K 1/0281 Reinforcement details thereof
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/038 Textiles used as reinforcing materials for organic insulating substrates H05K1/0366
• CPC Class Codes: H05K 1/0386 Paper sheets used as reinforcing materials for organic insulating substrates H05K1/0366
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 1/148 Arrangements of two or more hingeably connected rigid printed circuit boards, i.e. connected by flexible means
• CPC Class Codes: H05K 2201/0137 Materials
• CPC Class Codes: H05K 2201/05 Flexible printed circuits [FPCs]
• CPC Class Codes: H05K 2201/058 Direct connection between two or more FPCs or between flexible parts of rigid PCBs
• CPC Class Codes: H05K 2201/09945 Universal aspects, e.g. universal inner layers or via grid, or anisotropic interposer
• CPC Class Codes: H05K 2201/0999 Circuit printed on or in housing, e.g. housing as PCB; Circuit printed on the case of a component; PCB affixed to housing
• CPC Class Codes: H05K 2201/2009 Reinforced areas, e.g. for a specific part of a flexible printed circuit
• CPC Class Codes: H05K 3/22 Secondary treatment of printed circuits H05K3/1283 takes precedence; embedding circuits in grooves by pressure H05K3/107
• CPC Class Codes: H05K 3/4691 Rigid-flexible multilayer circuits comprising rigid and flexible layers, e.g. having in the bending regions only flexible layers

Abstract

A rip stop material is attached at a stress area of a flexible circuit board in order to strengthen the flexible circuit board and minimize ripping and cracking in the polyimide and/or the copper conductors of the circuit. A rip stop transition layer is formed and deposited at a location on the flexible circuit in order to minimize, reduce, if not preventing cracking and ripping of the circuit as it is bent and flexed. The rip stop transition layer can be placed at different locations on and within the flexible circuit in order to minimize cracking and ripping as the flexible circuit is bent, flexed and twisted.

Claims

1. A deformable electronic device comprising:

a. a deformable electronic device body comprising a center pre-preg section and a flexible base with coverlays coupled to the flexible base; and

b. a plurality of rip stop material layers deposited at boundary portions of the pre-preg section and the coverlays but not along entire surfaces of the coverlays, and at inside locations and along a length of the body, wherein at least two of the plurality rip stop material layers are positioned along the same plane within the body.

2. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers is deposited at a high stress location of the deformable electronic device.

3. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers comprises an open weave interlocking fabric.

4. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers is attached to one of a rigid, a rigid-flex, a stretch, a rigid-stretch, and a mechanism housing of the deformable electronic device.

5. The deformable electronic device of claim 1, wherein the deformable electronic device comprises a flexible circuit board.

6. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers is attached to the outsides of the deformable electronic device.

7. The deformable electronic device of claim 1, wherein at least two of the rip stop material layers are laminated along the same plane and on top of one of the coverlays.

8. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers is laminated on top of the flexible base before the coverlays are laminated.

9. The deformable electronic device of claim 1, wherein at least one of the rip stop material layers is deposited at a high twist area of the deformable electronic device.

10. The deformable electronic device of claim 1, wherein each of the coverlays includes a pre-preg area, wherein all pre-preg areas are vertically aligned within the body to form the pre-preg section, wherein the pre-preg section is coupled with a cap at each end of the pre-preg section.

11. The deformable electronic device of claim 10, wherein at least one of plurality of rip stop material layers is in contact with at least a portion of a surface of the pre-preg area of the each of the coverlays, wherein the pre-preg area of the each of the coverlays is centrally located in the each of the coverlays.

12. A method of strengthening a deformable electronic device including a flexible base, coverlays, and a center pre-preg section, that together form a body, the method comprising:

a. forming a plurality of rip stop material layers; and

b. depositing the plurality of rip stop material layers at inside locations and along a length of the body of the deformable electronic device, and also at boundary potions of the pre-preg section and the coverlays but not along the entire surfaces of the coverlays, wherein at least two of the plurality rip stop material layers are disjointedly positioned along the same horizontal plane within the body.

13. The method of claim 12, wherein at least one of the rip stop material layers is deposited at a high stress location of the deformable electronic device.

14. The method of claim 12, wherein at least one of the rip stop material layers comprises an open weave interlocking fabric.

15. The method of claim 12, wherein at least one of the rip stop material layers is attached to one of a rigid, a rigid-flex, a stretch, a rigid-stretch, and a mechanism housing of the deformable electronic device.

16. The method of claim 12, wherein the deformable electronic device comprises a flexible circuit board.

17. The method of claim 12, wherein at least one of the rip stop material layers is attached to the outsides of the deformable electronic device.

18. The method of claim 12, wherein at least two of the rip stop material layers are laminated along the same plane and on top of one of the coverlays.

19. The method of claim 12, wherein at least one of the rip stop material layer is laminated on top of the flexible base before the coverlays are laminated.

20. The method of claim 12, wherein at least one of the rip stop material layer is deposited at a high twist area of the deformable electronic device.