Baseline update procedure for touch sensitive device

• US 8,339,286 B2
• Filed: 03/31/2010
• Issued: 12/25/2012
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Cordeiro, Craig A.
• Primary Examiner(s): YOUNG, BRIAN K
• Application Number:
  US12/750,924
• Publication Number:
  US 20110241907A1
• Time in Patent Office: 1,000 Days
• Field of Search: 345/172, 345/178, 341/20, 341/33
• US Class Current: 341/20
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• 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: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/94026 Automatic threshold calibration; e.g. threshold automatically adapts to ambient conditions or follows variation of input

Abstract

A touch sensitive device implementing a routine that controls the device'"'"'s baseline update procedure in certain circumstances, and associated methods.

Claims

1. A method of determining to update baseline values associated with nodes on a mutual capacitive type touch sensitive device, comprising:

receiving data streams associated with the capacitive coupling at a plurality of nodes on a touch sensor, over a plurality of measurement cycles;

determining, based on the data streams, if a sufficient portion of the plurality of nodes have been trending toward or away from touch for a sufficient period of time; and

updating baseline values associated with at least some of the nodes on the touch sensor if a sufficient portion of the plurality of nodes have been trending toward or away from touch for a sufficient period of time.

2. The method of claim 1, wherein the touch sensitive device has a sensor subcomponent that is substantially transparent.

3. The method of claim 1, wherein a sufficient portion comprises at least 55% of the nodes.

4. The method of claim 1, wherein a sufficient period of time is at least one second.

5. The method of claim 1, wherein updating baseline values associated with at least some portion of the nodes comprises all of the nodes.

6. The method of claim 1, wherein the baseline value is a threshold value, the threshold value being indicative of a touch condition.

7. A touch sensitive device comprising:

a touch matrix-type touch sensor having a plurality of nodes;

electronics communicatively coupled to the nodes and configured to measure the capacitive coupling at individual nodes of the touch sensor;

wherein the electronics are configured to;

receive data streams indicative of the capacitive coupling at a plurality of nodes on the touch sensor

determine, based on the data streams, if a sufficient portion of the plurality of nodes have been trending toward or away from touch for a sufficient period of time; and

,

update baseline values associated with at least some of the nodes on the touch sensor, when a sufficient portion of the plurality of nodes have been trending toward or away from touch for a sufficient period of time.

8. The touch sensitive device of claim 7, wherein the touch sensor is substantially transparent.

9. The touch sensitive device of claim 7, wherein a sufficient period of time is at least one second.

10. The touch sensitive device of claim 7, wherein a sufficient portion comprises at least 55% of the nodes.

11. The touch sensitive device of claim 7, wherein the baseline value is a threshold value, the threshold value being indicative of a touch condition.