Touch sensitive devices with composite electrodes

• US 8,279,187 B2
• Filed: 07/29/2009
• Issued: 10/02/2012
• Est. Priority Date: 08/01/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Geaghan, Bernard O.
• Primary Examiner(s): Sitta, Grant
• Assistant Examiner(s): Siddiqui, Saiful A
• Application Number:
  US12/511,487
• Publication Number:
  US 20100026664A1
• Time in Patent Office: 1,161 Days
• Field of Search: 345156-179, 178 1801- 1805
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• 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 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A matrix touch panel having upper and lower electrodes, the upper electrodes being composite electrodes made of a plurality of spaced micro-wires, and allowing, for example, an electric field from lower electrodes to pass between the micro-wires and thereby capacitively couple with a touching object, such as a finger.

Claims

1. A multi-layer touch panel, comprising:

a first layer comprising a transparent touch surface;

an upper electrode layer comprising a plurality of composite electrodes comprised of a plurality of metal or metal alloy micro-wire conductors having a cross-sectional dimension of less than 10 microns;

a lower electrode layer comprising a plurality of indium oxide-based electrodes, the upper electrodes and lower electrodes defining an electrode matrix having nodes where the upper and lower electrodes cross over, and wherein the upper electrode layer is disposed between the first layer and the lower electrode layer; and

a dielectric layer disposed between the upper electrode layer and the lower electrode layer.

2. The multi-layer touch panel of claim 1, wherein the composite electrodes are configured to be pervious to an electric field from the electrodes in the lower electrode layer, allowing the electric field from electrodes in the lower electrode layer to pass through spaces between the micro-wire conductors that comprise composite electrodes in the upper electrode layer.

3. The multi-layer touch panel of claim 1, wherein the micro-wires have a cross-sectional dimension of less than 9 microns.

4. The multi-layer touch panel of claim 1, wherein the micro-wires have a cross-sectional dimension of less than 3 microns.

5. The multi-layer touch panel of claim 1, wherein the micro-wires have a cross-sectional dimension of less than 5 microns.

6. The multi-layer touch panel of claim 1, wherein the micro-wires have a cross-sectional dimension of between 1 and 4 microns.

7. The multi-layer touch panel of claim 1, wherein the micro-wires of the composite electrodes cover two percent or less of the surface area of the upper electrode layer.

8. The multi-layer touch panel of claim 1, further comprising one or more additional layers disposed between, above, or below any of the mentioned layers.

9. The multi-layer touch panel of claim 1, wherein the electrodes of the upper electrode layer are orthogonal to electrodes of the lower electrode layer.

10. The multi-layer touch panel of claim 1, wherein the micro-wire conductors that comprise the composite conductors are substantially uniformly spaced on the upper electrode layer.

11. The multi-layer touch panel of claim 1, wherein the center-to-center spacing of the micro-wire conductors that comprise at least one of the composite conductors is less than 4 mm.

12. The multi-layer touch panel of claim 11, wherein the micro-wire conductors that comprise at least one composite electrode include conductor bridges.

13. The multi-layer touch panel of claim 1, wherein the number of micro-wire conductors that comprise at least one of the composite conductors is between the range of 2 and 10, inclusive.

14. The multi-layer touch panel of claim 1, further comprising:

a drive circuit configured to electrically drive at least one of the lower electrodes; and

,

a receive circuit configured to sense signals indicative of capacitance between an electrode in the upper electrode layer and an electrode in the lower electrode layer.

15. The multi-layer touch panel of claim 1, further comprising:

a drive circuit configured to electrically drive at least one electrode in upper electrode layer; and

,

a receive circuit configured to sense signals indicative of capacitance between the at least one electrode in the lower electrode layer and a ground reference voltage.

16. A method for identifying locations of touches or near-touches on a touch sensitive apparatus, comprising:

sensing, with an electronic controller, a value indicative of the change of mutual capacitance between an overlapping upper electrode and a lower electrode disposed in a matrix-type touch sensor, the change in mutual capacitance induced by the presence of an object proximate to the touch sensor, wherein the upper electrode is a composite metal or metal alloy electrode comprised of a plurality of micro-wire conductors having an average cross-sectional dimension of less than 10 microns and wherein the lower electrode is comprised of an indium oxide-based material.

17. The method of claim 16, wherein the composite electrode is pervious to an electric field from the lower electrode, thus allowing the electric field from the lower electrode to pass through spaces between the micro-wire conductors that comprise composite conductors in the upper electrode layer.

18. The method of claim 16, wherein the micro-wire conductors have an average cross-sectional dimension of less than 5 microns.

19. The method of claim 16, wherein the center-to-center spacing of the micro-wire conductors that comprise the composite conductor is less than 4 mm.

20. The method of claim 16, wherein the number of micro-wire conductors that comprise the composite conductor is between 2 and 10.