Touch sensor back plane ground connection

• US 8,573,984 B2
• Filed: 12/19/2012
• Issued: 11/05/2013
• Est. Priority Date: 07/26/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Miller, Thayne M.
• Primary Examiner(s): Johnson, Amy Cohen
• Assistant Examiner(s): Imas, Vladimir
• Application Number:
  US13/720,455
• Publication Number:
  US 20130133947A1
• Time in Patent Office: 321 Days
• Field of Search: 439/67, 439/65, 178 1801- 1811, 345173-178
• US Class Current: 439/67
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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: H01R 4/06 Riveted connections by explosion H01R4/08

Abstract

Touch sensor panels can use touch sensors to detect the presence and location of a touch event. In order for the touch sensors to function reliably, the back plane of the touch sensor panel should be grounded. Supplying this ground connection can provide a uniform electrical reference point from which changes in voltage and capacitance due to a touch event can be measured. Without this ground connection, touch sensors may misrepresent the touch event. Various embodiments of the present disclosure provide different means for providing a ground connection for the back plane of a touch sensor panel. These embodiments are designed to provide a reliable ground connection even in the presence of various failure conditions.

Claims

1. A flexible tail of a back plane of a touch sensor panel, wherein the flexible tail has a conductive side and a non-conductive side, comprising:

a non-critical bend at an end of the flexible tail, wherein the non-conductive side of the flexible tail is on an inner surface of the non-critical bend, wherein a screw through the non-critical bend electrically connects the flexible tail to a ground connection.

2. The flexible tail of claim 1, wherein the flexible tail is positioned to maintain electrical connectivity between the back plane and the ground connection if a crack occurs along the non-critical bend.

3. The flexible tail of claim 1, wherein the flexible tail is connected to the back plane at a first edge of the touch sensor panel, wherein the end of the flexible tail is connected to the ground connection at a second edge of the touch sensor panel and wherein the first edge is adjacent to the second edge.

4. The flexible tail of claim 3, wherein the flexible tail comprises a first critical bend at the first edge of the touch sensor panel.

5. The flexible tail of claim 4, wherein the flexible tail comprises a second critical bend between the first critical bend and the non-critical bend.

6. The flexible tail of claim 1, wherein the conductive side is on an outer surface of the non-critical bend and wherein the conductive side is in contact with a head of the screw and in contact with the ground connection.

7. The flexible tail of claim 1, wherein the screw passes through two holes in the flexible tail.

8. The flexible tail of claim 1, wherein the ground connection comprises a device chassis.

9. The flexible tail of claim 1, wherein a washer is inserted between a head of the screw and the flexible tail.

10. A method for electrically connecting a flexible tail of a touch sensor panel, comprising:

forming a flexible tail having a conductive side and a non-conductive side, wherein a first end of the flexible tail, is connected to a back plane of the touch sensor panel;

folding a second end of the flexible tail to form a non-critical bend, wherein the non-conductive side is on an inner surface of the non-critical bend; and

inserting a screw through the non-critical bend to electrically connect the flexible tail to a ground connection.

11. The method of claim 10, wherein inserting the screw through the non-critical bend comprises inserting the screw through the non-critical bend to electrically connect the flexible fail to a device chassis.

12. The method of claim 10, wherein folding the second end of the flexible tail to form a non-critical bend comprises folding the second end such that the conductive side on the second end of the flexible tail is positioned against a head of the screw.

13. The method of claim 10, wherein folding the second end of the flexible tail to form a non-critical bend comprises folding the second end such that the conductive side on the second end of the flexible tail is positioned against the device chassis.

14. The method of claim 10, further comprising folding the flexible tail to form a first critical bend at the first edge of the touch sensor panel.

15. The method of claim 10, further comprising folding the flexible tail to form a second critical bend between the first critical bend and the non-critical bend.

16. A flexible tail configured to electrically connect a first component of a touch sensor panel to a second component of the touch sensor panel, the flexible tail comprising:

a non-conductive side;

a conductive side; and

a non-critical bend, wherein the conductive side is on an outer surface of the non-critical bend, wherein the flexible tail is configured to be fastened to the second component by inserting a screw through two holes in the flexible tail at the non-critical bend, wherein the conductive side is in electrical contact with the second component and the screw.

17. The flexible tail of claim 16, wherein the flexible tail is configured to maintain electrical connectivity between the first component and the second component through the screw if corrosion forms between the flexible tail and the second component.

18. The flexible tail of claim 16, wherein the flexible tail is positioned to maintain electrical connectivity between the first component and the second component if corrosion forms between the flexible tail and a head of the screw.

19. The flexible tail of claim 16, wherein the conductive side is made from aluminum or copper and the non-conductive side is made from PET or plastic.

20. The flexible tail of claim 16, wherein the second component provides a ground for the touch sensor panel.