Flex circuit with single sided routing and double sided attach

• US 8,456,851 B2
• Filed: 05/16/2008
• Issued: 06/04/2013
• Est. Priority Date: 05/16/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Grunthaner, Martin Paul
• Primary Examiner(s): Dinh, Tuan T
• Assistant Examiner(s): SAWYER, STEVEN T
• Application Number:
  US12/122,441
• Publication Number:
  US 20090283300A1
• Time in Patent Office: 1,845 Days
• Field of Search: 174/254, 361/751, 361/750, 361/810, 361/749, 178 1801- 1806, 349/150, 349/151, 349/158, 349/493
• US Class Current: 361/749
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: H05K 1/118 specially for flexible printed circuits, e.g. using folded portions
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 2201/053 Tails
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2203/1572 Processing both sides of a PCB by the same process; Providing a similar arrangement of components on both sides; Making interlayer connections from two sides
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/361 Assembling flexible printed circuits with other printed circuits
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A flex circuit having conductive traces formed on only one side of a base film for attaching to both sides of a DITO touch sensor panel is disclosed. By having conductive traces formed on only one side of the base film, the number of process steps and fabrication cost can be reduced because only a single etching step is needed. Furthermore, because the flex circuit is thinner, the resultant space savings can be utilized for other features in a device without enlarging the overall device package.

Claims

1. A flex circuit for connecting to both sides of a touch sensor panel, comprising:

a base film having first and second opposing surfaces, a width, and first and second ends terminating in first and second attachment areas, the first and second attachment areas widened as compared to the width of the base film, and

a layer of conductive traces formed on the first surface of the base film, the second surface formed free of conductive material, the conductive traces on the first surface terminating with conductors in the first and second attachment areas;

wherein the base film further includes a third end terminating in a tail, and wherein the conductors in the first and second attachment areas are routed to the tail;

wherein the base film and conductive traces form a flexible stackup capable of being folded for attachment to first and second opposing sides of the touch sensor panel; and

wherein the conductors in the first attachment area are located along a length of the first attachment area and the conductors in the second attachment area are located along a width of the second attachment area at one or more distal ends of the second attachment area for making electrical connections with the first and second opposing sides of the touch sensor panel in areas that do not directly oppose each other.

2. The flex circuit of claim 1, wherein the first and second attachment areas form first and second T-shaped areas at the first and second ends of the base film.

3. The flex circuit of claim 1, wherein the conductors in the first attachment area are located along a top of the first T-shaped area and the conductors in the second attachment area are located at one or both ends of the second T-shaped area.

4. The flex circuit of claim 2, wherein the second T-shaped are is wider than the first T-shaped area.