Flexible touchpad circuit with mounted circuit board

• US 6,002,594 A
• Filed: 12/19/1997
• Issued: 12/14/1999
• Est. Priority Date: 12/20/1996
• Status: Expired due to Term

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Logitech, Inc. (Logitech International SA)
• Inventors: Kasser, Bernard, Bisset, Stephen J., Ledin, Marc
• Primary Examiner(s): SPARKS, DONALD ALAN
• Application Number:
  US08/999,908
• Time in Patent Office: 725 Days
• Field of Search: 178/17 A, 178/17 B, 178/17 C, 178/18, 178/19, 178/20, 178/110, 200/512, 200/513, 200/515, 200/520, 361/749, 361/784, 361/781, 361/789, 361/790, 361/803
• US Class Current: 361/803
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H01H 2207/008 Adhesive means; Conductive adhesive
• CPC Class Codes: H01H 2239/01 combined with other elements on the same substrate
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• 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 2201/10053 Switch
• 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

Abstract

An improved flexible substrate for a touchpad, with the flexible substrate having conductive ink for forming a sensor array. A printed circuit board is also used, but only for the components which need to connect to the array, and not the array, thus giving a smaller printed circuit board. The printed circuit board can have the components compactly mounted on it taking advantage of the close spacing available in PC board technology. The PC board itself has wider spacing on its contacts at its outer edges, allowing it to be attached by conductive glue to the flexible substrate.

Claims

1. A touchpad for providing an input to a computer display, comprising:

an array of touchpad traces formed with conductive ink on a flexible substrate;

a plurality of connecting conductive traces for connecting said array of traces to other components;

a circuit board having contacts bonded to said connecting conductive traces, said contacts being bonded using a conductive adhesive, said contacts being sufficiently spaced to allow conductive adhesive to bond said contacts to said connecting conductive traces without contacting an adjacent trace;

a plurality of components mounted on said circuit board and connected to lines on said circuit board which are connected to said contacts, at least a plurality of said lines being connected to at least one of said components with a spacing closer than a spacing of said contacts.

2. The touchpad of claim 1 further comprising:

a ground plane deposited on a surface of said circuit board opposite said components.

3. The touchpad of claim 1 wherein said flexible substrate is polyester.

4. The touchpad of claim 1 wherein said components are mounted with a spacing closer than a spacing which would be possible if said components were mounted directly on said flexible substrate.

5. A touchpad for providing an input to a computer display, comprising:

an array of touchpad traces formed with conductive ink on a flexible substrate;

a plurality of connecting conductive traces for connecting said array of traces to other components;

a circuit board having contacts bonded to said connecting conductive traces, said contacts being bonded using a conductive adhesive, said contacts being sufficiently spaced to allow conductive adhesive to bond said contacts to said connecting conductive traces without contacting an adjacent trace;

a plurality of components mounted on said circuit board and connected to lines on said circuit board which are connected to said contacts, at least a plurality of said lines being connected to at least one of said components with a spacing closer than a spacing of said contacts; and

a ground plane deposited on a surface of said circuit board opposite said components;

wherein said components are mounted with a spacing closer than a spacing which would be possible if said components were mounted directly on said flexible substrate.