Technique for reducing wasted material on a printed circuit board panel

• US 7,690,104 B2
• Filed: 04/04/2008
• Issued: 04/06/2010
• Est. Priority Date: 02/20/2008
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Salehi, Amir, Rosenblatt, Michael N.
• Primary Examiner(s): Tugbang; A. Dexter
• Assistant Examiner(s): ANGWIN, DAVID PATRICK
• Application Number:
  US12/062,855
• Publication Number:
  US 20090205200A1
• Time in Patent Office: 732 Days
• Field of Search: 298/29, 298/30, 298/34, 298/40, 174/254, 174/255, 439 65- 69, 349/150, 2281801-18022
• US Class Current: 29/830
• 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 2201/058 Direct connection between two or more FPCs or between flexible parts of rigid PCBs
• CPC Class Codes: H05K 2201/10393 Clamping a component by an element or a set of elements
• CPC Class Codes: H05K 2203/0152 Temporary metallic carrier, e.g. for transferring material affixing a prefabricated conductor pattern formed by electroplating or electroforming on a metallic carrier H05K3/205
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/007 Manufacture or processing of a substrate for a printed circuit board supported by a temporary or sacrificial carrier H05K1/187, H05K3/20 and H05K3/4682 take precedence
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/341 Surface mounted components
• CPC Class Codes: H05K 3/3494 Heating methods for reflowing of solder using integral heating means H05K1/0212
• CPC Class Codes: H05K 3/361 Assembling flexible printed circuits with other printed circuits
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49133 with component orienting
• CPC Class Codes: Y10T 29/49144 by metal fusion
• CPC Class Codes: Y10T 29/5313 Means to assemble electrical device
• CPC Class Codes: Y10T 29/53174 Means to fasten electrical component to wiring board, base, or substrate
• CPC Class Codes: Y10T 29/53265 with work-holder for assembly

Abstract

A process for assembling a rigid-flex printed circuit board (PCB) is presented. During operation, the process receives rigid-flex PCBs that are to be coupled together, wherein a rigid-flex PCB includes flexible PCBs coupled to rigid PCBs. The process then places the PCBs onto a carrier which is configured to: align the PCBs so that bond regions located on the flexible PCBs overlap with bond regions located on corresponding flexible PCBs, and apply pressure to the overlapped bond regions. The process then sends the carrier through a reflow oven which reflows solder on the PCBs so that the components become mechanically and electrically coupled to the PCBs. The temperature profile generated by the reflow oven and the pressure applied by the carrier cures and sets an anisotropic conductive film located in the bond regions so that the overlapped flexible PCBs become mechanically and electrically coupled together.

Claims

1. A method for assembling a rigid-flex printed circuit board (PCB), comprising:

receiving at least two rigid-flex PCBs that are to be coupled together, wherein each of the rigid-flex PCBs includes at least one flexible PCB coupled to at least one rigid PCB;

placing the at least two rigid-flex PCBs onto a carrier which is configured to;

align the at least two rigid-flex PCBs so that bond regions located on the flexible PCBs of each of the at least two rigid-flex PCBs overlap, and

apply pressure to the overlapped bond regions;

placing components at specified locations on the at least two rigid-flex PCBs; and

sending the carrier through a reflow oven which is configured to generate a temperature profile that reflows solder on the at least two rigid-flex PCBs so that the components become mechanically and electrically coupled to the at least two rigid-flex PCBs;

wherein the temperature profile generated by the reflow oven and the pressure applied by the carrier cures and sets an anisotropic conductive film (ACF) located in the bond regions so that the overlapped flexible PCBs become mechanically and electrically coupled together.

2. The method of claim 1, wherein prior to placing the components, the method further comprises depositing solder on conductive pads at the specified locations on the at least two rigid-flex PCBs.

3. The method of claim 2, wherein placing components at the specified locations involves placing the components on the deposited solder.

4. The method of claim 1, wherein the pressure applied by the carrier is constant.

5. The method of claim 1, wherein the pressure applied by the carrier is a specified function of the temperature.

6. The method of claim 5,

wherein as the temperature rises, the pressure applied by the carrier increases;

wherein as the temperature decreases, the pressure applied by the carrier remains constant until the temperature decreases below a specified temperature; and

wherein after the temperature decreases to a specified temperature, the pressure applied by the carrier decreases.

7. The method of claim 1, wherein the carrier includes a pressure applying mechanism which includes one or more of:

a screw;

a wing nut;

a latch; and

a clamp.