Flexible touchpad sensor grid for conforming to arcuate surfaces

• US 6,680,731 B2
• Filed: 01/11/2001
• Issued: 01/20/2004
• Est. Priority Date: 01/11/2000
• Status: Active Grant

• Current Assignee: Cirque Corporation
• Original Assignee: Cirque Corporation
• Inventors: Taylor, Brian, Woolley, Richard, Lee, Daniel, Gerpheide, George
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): Alphonse, Fritz
• Application Number:
  US09/759,609
• Publication Number:
  US 20010055004A1
• Time in Patent Office: 1,104 Days
• Field of Search: 345/173, 345/179, 345/174, 345/175, 345/156
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0213 Arrangements providing an integrated pointing device in a keyboard, e.g. trackball, mini-joystick for pointing devices integrated in a laptop computer G06F1/169; joysticks G05G9/047; constructional details of pointing devices G06F3/033
• 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: H05K 2201/0367 Metallic bump or raised conductor not used as solder bump solder materials or compositions and methods of application thereof H05K3/3457
• CPC Class Codes: H05K 3/305 Affixing by adhesive
• CPC Class Codes: H05K 3/365 by abutting, i.e. without alloying process

Abstract

A touchpad formed from the combination of a flexible and non-conductive material used for a touch-sensitive surface, and a PC board on which is mounted the touchpad circuitry, wherein touchpad sensing electrodes are disposed on the touch-sensitive surface by creating electrical traces formed from conductive ink, the touch-sensitive surface being capable of conforming to various arcuate surfaces, and being capable of sensing through a protective housing such that the touch-sensitive surface is protected, and does not come in direct contact with the pointing object.

Claims

1. A touchpad for providing data input to a computer system by tracking movement of an object in contact with the touchpad, and which includes a flexible touch-sensitive surface that conforms to arcuate surfaces such that the flexible touch-sensitive surface is non-planar, said touchpad comprising:

at least two flexible and non-conductive sheets having at least three touchpad sensing electrodes disposed thereon, wherein the at least two flexible and non-conductive sheets overlap such that the at least three touchpad sensing electrodes form a grid which defines a touch-sensitive area of the touchpad, and wherein the at least two flexible and non-conductive sheets can bend to thereby conform to an arcuate surface such that the flexible touch-sensitive surface is not in a single plane, wherein movement of an object is detected and followed across the arcuate surface;

a printed circuit board; and

touchpad control circuitry which is mounted on the printed circuit board, wherein the touchpad control circuitry is electrically coupled to the touchpad sensing electrodes so as to receive sensing information therefrom in order to detect contact of the object with the touchpad, track movement of the object across the touchpad, and removal of the object from the touchpad to thereby perform such a function as cursor control for the computer system, and wherein the touchpad control circuitry generates a plurality of signals that correspond to data input from the touchpad.

2. The touchpad as defined in claim 1 wherein the at least two flexible and non-conductive sheets are selected from the group of flexible and non-conductive sheets including plastic and mylar.

3. The touchpad as defined in claim 2 wherein the touchpad sensing electrodes are formed from conductive ink.

4. The touchpad as defined in claim 3 wherein the touchpad further comprises a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board, said connection system comprising:

a first non-conductive sheet secured to the printed circuit board;

a second non-conductive sheet partially secured to the printed circuit board, parallel to the first non-conductive sheet, and spaced apart therefrom to form a gap therebetween, wherein the second non-conductive sheet is not secured along the gap; and

a row of solder bumps disposed underneath the second non-conductive sheet where it is not secured to the printed circuit board, parallel to and near an edge of the gap, wherein the portion of the at least two flexible and non-conductive sheets is disposed between the second non-conductive sheet and the row of solder bumps, and wherein touchpad sensing electrodes are in contact with the row of solder bumps.

5. The touchpad as defined in claim 3 wherein the touchpad further comprises a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board, said connection system comprising:

at least two rows of solder bumps disposed on the printed circuit board, wherein the at least two rows of solder bumps are spaced apart to form a gap therebetween; and

a portion of the at least two flexible and non-conductive sheets disposed so as to cover the at least two rows of solder bumps, wherein the portion of the at least two flexible and non-conductive sheets that is disposed over the gap is secured to the printed circuit board so as to fill the gap, wherein the gap between the at least two solder bumps is sufficient to create tension on the portion of the at least two flexible and non-conductive sheets that is secured thereto.

6. The touchpad as defined in claim 5 wherein the touchpad further comprises an adhesive that is used to secure the portion of the at least two flexible and non-conductive sheets to the printed circuit board.

7. The touchpad as defined in claim 6 wherein the touchpad further comprises providing the at least two flexible and non-conductive sheets which have stiffness sufficient to create pressure to maintain electrical contact between touchpad sensing electrodes on the at least two flexible and non-conductive sheets, and the at least two rows of solder bumps.

8. The touchpad as defined in claim 7 wherein the touchpad further comprises staggering solder bumps within the at least two rows of solder bumps, such that a first row of solder bumps is offset from a second row of solder bumps, relative to the portion of the at least two flexible and non-conductive sheets.

9. A method for providing a touchpad having a flexible touch-sensitive surface that is coupled to arcuate surfaces, said method comprising the steps of:

(1) providing a flexible touch-sensitive surface that is non-planar and that conforms to arcuate surfaces formed from at least two flexible and non-conductive sheets coupled together and having touchpad sensing electrodes disposed thereon, a printed circuit board, and touchpad control circuitry which is mounted on the printed circuit board, wherein the touchpad control circuitry is electrically coupled to the touchpad sensing electrodes so as to receive sensing information therefrom, and wherein the touchpad control circuitry generates a plurality of signals that correspond to data input from the touchpad;

(2) disposing the flexible touch-sensitive surface against a mounting surface, wherein the mounting surface is sufficiently thin to thereby enable the flexible touch-sensitive surface to detect a pointing object on an opposite side thereof; and

(3) detecting and tracking the pointing object that touches and moves along the opposite side of the mounting surface by using the touchpad control circuitry to detect contact of the pointing object with the opposite side of the mounting surface, track movement of the pointing object, and removal of the pointing object to thereby perform such a function as cursor control for a computer system.

10. The method as defined in claim 9 wherein the method further comprises the step of securing the flexible touch-sensitive surface against the mounting surface using a non-conductive adhesive.

11. The method as defined in claim 10 wherein the method further comprises the step of selecting the at least two flexible and non-conductive sheets from the group of flexible and non-conductive sheets including plastic and mylar.

12. The method as defined in claim 11 wherein the method further comprises the step of forming the touchpad sensing electrodes from conductive ink.

13. The method as defined in claim 12 wherein the method further comprises the steps of:

(1) securing a first non-conductive sheet to the printed circuit board;

(2) partially securing a second non-conductive sheet to the printed circuit board, parallel to the first non-conductive sheet, and spaced apart therefrom to form a gap therebetween, wherein the second non-conductive sheet is not secured along the gap; and

(3) providing a row of solder bumps underneath the second non-conductive sheet where it is not secured to the printed circuit board, parallel to and near an edge of the gap, wherein the portion of the at least two flexible and non-conductive sheets is disposed between the second non-conductive sheet and the row of solder bumps, and wherein touchpad sensing electrodes are in contact with the row of solder bumps.

14. The method as defined in claim 12 wherein the method further comprises the step of providing a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board that does not rely upon a pressure connector.

15. The method as defined in claim 14 wherein the method further comprises the step of utilizing a non-conductive adhesive to secure the portion of the at least two flexible and non-conductive sheets to the printed circuit board.

16. The method as defined in claim 15 wherein the method further comprises the step of staggering solder bumps within the at least two rows of solder bumps, such that a first row of solder bumps is offset from a second row of solder bumps, relative to the portion of the at least two flexible and non-conductive sheets.

17. The method as defined in claim 14 wherein the method further comprises the steps of:

(1) providing at least two rows of solder bumps on the printed circuit board, wherein the at least two rows of solder bumps are spaced apart to form a gap therebetween, and

(2) securing a portion of the at least two flexible and non-conductive sheets so as to cover the at least two rows of solder bumps, wherein the portion of the at least two flexible and non-conductive sheets that is disposed over the gap is secured to the printed circuit board so as to fill the gap.