INTERLEAVED ELECTRODES FOR TOUCH SENSING

• US 20110063251A1
• Filed: 11/23/2010
• Published: 03/17/2011
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Hagermoser, Edward S., Badaye, Massoud S., Geaghan, Bernard O.
• Granted Patent: US 8,004,499 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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 3/0443 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

Abstract

A capacitive touch sensing system includes a touch surface and sets of substantially parallel electrodes arranged in relation to the touch surface. Each electrode set includes a primary electrode electrically connected to at least two sub-electrodes. The primary electrode is capable of producing greater capacitive coupling to a touch in proximity with the touch surface in relation to capacitive coupling of the at least two sub-electrodes. The sub-electrodes of the electrode sets are arranged in an interleaved pattern configured to increase an effective area of capacitive coupling associated with each electrode set.

Claims

1. A capacitive touch sensing system, comprising:

a touch surface; and

sets of electrically connected and substantially parallel electrodes arranged in relation to the touch surface, each set of electrodes including a primary electrode and at least two sub-electrodes disposed on either side of the primary electrode and having a smaller surface area than the primary electrode, wherein the sub-electrodes of the electrode sets are interleaved.

2. The touch sensing system of claim 1, wherein a width of each primary electrode varies along a longitudinal axis of the primary electrode.

3. The touch sensing system of claim 1, wherein a width of each sub-electrode varies along a longitudinal axis of the sub-electrode.

4. The touch sensing system of claim 1, wherein the electrode sets are disposed on two layers, wherein electrodes on a first layer include geometric elements and electrodes on a second layer include geometric elements complementary with the geometric elements of the first layer electrodes, the complementary geometric elements of the first and second layer electrodes configured to enhance capacitive coupling of the second layer electrodes.

5. The touch sensing system of claim 1, wherein:

the primary electrode of each electrode set comprises a first number of adjacent electrode elements having substantially equal width; and

the at least two sub-electrodes of each electrode set comprises a second number of adjacent electrode elements having substantially equal width.

6. A method for making a touch sensor comprising disposing sets of electrodes on a substrate in accordance with an interleaved pattern configured to increase an effective area of capacitive coupling associated with each set of electrodes, each set of electrodes comprising a primary electrode capable of producing greater capacitive coupling to a touch in relation to capacitive coupling of sub-electrodes electrically connected and substantially parallel to the primary electrode, the primary electrode disposed between at least two of the sub-electrodes.

7. The method of claim 6, wherein the interleaved pattern is configured to shape touch response profiles associated with the electrode sets, each touch response profile representative of a relationship between touch signal amplitude and touch position relative to a particular electrode set.

8. The method of claim 6, wherein disposing the electrode sets on the substrate in accordance with the interleaved pattern comprises disposing the electrode sets in a single layer.

9. The method of claim 6, wherein disposing the electrode sets on the substrate in accordance with the interleaved pattern comprises disposing a first portion of the electrode sets in a first layer and a second portion of the electrode sets in a second layer.

10. The method of claim 6, wherein the primary electrode of each electrode set has a larger surface area than the sub-electrodes of each electrode set.

11. The method of claim 6, further comprising electrically connecting the primary electrode and sub-electrodes of each electrode set at one end of the primary electrode.

12. The method of claim 6, further comprising electrically connecting the primary electrode and sub-electrodes of each electrode set at both ends of the primary electrode.

13. The method of claim 6, wherein disposing the electrode sets on the substrate comprises disposing a plurality of substantially equally spaced and substantially equal width electrode elements on the substrate, wherein the primary electrode of each electrode set includes a first number of adjacent electrode elements and the sub-electrodes of each electrode set include a second number of adjacent electrode elements.