Touch Screen Sensor

• US 20100123670A1
• Filed: 04/10/2009
• Published: 05/20/2010
• Est. Priority Date: 11/15/2008
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Philipp, Harald
• Granted Patent: US 9,244,568 B2
• Time in Patent Office: Days
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

A two-dimensional touch sensor comprising a plurality of electrodes arranged in a mesh pattern on a substrate. Each electrode is formed by interconnected metal traces, the metal being intrinsically opaque, but the metal traces being sufficiently narrow to be practically invisible. The metal traces have a width less than or equal to 10 μm and occupy less than or equal to 5% of the area of each electrode. The electrodes can be deposited additively via a printing process, for example using copper as the metal. The narrow width of the tracks allows the film to be highly transparent, since the electric field used in capacitive touch screens can be made to propagate with very low metal densities.

Claims

1. A two-dimensional touch sensor comprising a plurality of electrodes arranged in a pattern on a substrate, each electrode being formed of an interconnected mesh of metal traces, the metal being intrinsically opaque, but the metal traces being sufficiently narrow to be practically invisible.

2. The two-dimensional sensor of claim 1, wherein the metal traces have a width less than or equal to 10 μ

m.

3. The two-dimensional sensor of claim 1, wherein the metal traces occupy less than or equal to 5% of the area of each electrode.

4. The two-dimensional sensor of claims 1, wherein the electrodes are arranged in a single layer.

5. The two-dimensional sensor of claims 1, wherein the electrodes are arranged in two layers separated by a dielectric.

6. The two-dimensional touch sensor of claim 1, wherein adjacent electrodes are spaced apart by a plurality of islands also made of interconnected metal traces, the metal traces of the islands being visually and electrically similar to the metal traces of the electrodes.

7. The two-dimensional touch sensor of claim 1, wherein each electrode is subdivided into upper and lower parts, in that the metal traces from the upper and lower parts are connected only at a distal end of the electrode, there being no connection between metal traces in the upper and lower parts from the distal end to first and second proximal ends of the electrode.

8. The two-dimensional touch sensor of claim 7, further comprising first and second electrical connections for each electrode connected to respective first and second proximal ends thereof.

9. The two-dimensional touch sensor of claim 8, wherein the electrodes comprise a plurality of X electrodes spaced apart by a plurality of Y electrodes;

wherein the second proximal end of each X electrode is electrically connected to the first proximal end of the adjacent X electrode via a resistive element; and

wherein the second proximal end of each Y electrode is electrically connected to the first proximal end of the adjacent Y electrode.

10. A method of manufacturing a capacitive touch sensor, the method comprising the steps of:

providing a substrate; and

depositing a plurality of electrodes on at least one side of the substrate, each electrode being formed of an interconnected mesh of metal traces, the metal being intrinsically opaque, but the metal traces being sufficiently narrow to be practically invisible.

11. The method of claim 10, wherein the metal traces have a width less than or equal to 10 μ

m.

12. The method of claim 11, wherein the metal traces occupy less than or equal to 5% of the area of each electrode.

13. The method of claim 10, wherein each electrode is subdivided into upper and lower parts, in that the metal traces from the upper and lower parts are connected only at a distal end of the electrode, there being no connection between metal traces in the upper and lower parts from the distal end to first and second proximal ends of the electrode.

14. A method of testing a capacitive touch sensor manufactured according to claim 13, comprising:

applying a first voltage to the first proximal end of one of the plurality of electrodes while connecting the proximal ends of all other electrodes to ground and measuring a second voltage at the second proximal end of the one electrode;

repeating the previous step for all other electrodes; and

failing the sensor if the second voltage is anomalously low compared to the first voltage for any of the electrodes, and passing the sensor otherwise.