Systems and methods of moisture detection and false touch rejection on touch screen devices

Patent metadata

Field	Value
Publication number	US-9310934-B2
Application number	US-201414540940-A
Country	US
Kind code	B2
Filing date	Nov 13, 2014
Priority date	Feb 21, 2014
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

The presence of moisture on a touch screen device can mimic a user's touch causing false input detection and recognition. Disclosed are systems and methods for detecting the presence of moisture on a touch screen device.

First claim

What is claimed is:

1. A touch screen apparatus, comprising:
a touch screen having a plurality of sensing nodes, each sensing node being configured to sense a screen touch event and produce a corresponding touch signal;
a sensing circuit configured to receive touch signals from the plurality of sensing nodes and to produce a screen signal comprising each location of each sensing node and a corresponding value representative of the received touch signal at each location of each sensing node;
a memory component in communication with the sensing circuit, the memory component configured to store screen signal information; and
a processor in communication with the memory component, the processor configured to:
retrieve screen signal information from the memory component,
determine if the screen signal information includes one or more sensing node locations with corresponding values indicative of a first local maximum value having a value less than a first threshold value and greater than a second threshold value,
determine if the screen signal information includes a first sensing node location within a defined proximity to the one or more sensing node locations with corresponding values indicative of a first local maximum, the first sensing node location being in a region of sensing node locations, wherein each value of each sensing node location in the region is less than a third threshold value that is less than or equal to the second threshold value, and each sensing node location in the region is adjacent to another sensing node location in the region, and
determine that moisture is in contact with the touch screen at the one or more sensing node locations with corresponding values indicative of a first local maximum based on at least the inclusion of the first sensing node location.

2. The apparatus of claim 1 , wherein the defined proximity is based on at least a distance threshold.

3. The apparatus of claim 1 , wherein the processor is further configured to determine that moisture is in contact with the touch screen at sensing node locations associated with the region based on at least the inclusion of the first sensing node location.

4. The apparatus of claim 1 , wherein the first threshold is less than a lowest value associated with a finger touch for the screen signal information.

5. The apparatus of claim 1 , wherein the second threshold signal value is greater than a highest value associated with noise for the screen signal information.

6. The apparatus of claim 1 , wherein the processor is further configured to determine if the screen signal information includes one or more sensing node locations with corresponding values indicative of a second local maximum value, the second local maximum value being less than the first threshold value and greater than the second threshold value.

7. The apparatus of claim 6 , wherein the processor is further configured to determine if the screen signal information includes a second sensing node location within the defined proximity to the one or more sensing node locations with corresponding values indicative of a second local maximum, the second sensing node location being in the region.

8. The apparatus of claim 7 , wherein the determination that moisture is in contact with the touch screen at the one or more sensing node locations with corresponding values indicative of a first local maximum is further based on at least the inclusion of the second sensing node location.

9. A moisture detection method, comprising:
receiving touch signals from a plurality of sensing nodes of a touch screen, each sensing node being configured to sense a screen touch event and produce a corresponding touch signal;
producing screen signal information comprising each location of each sensing node and a corresponding value representative of the received touch signal at each location of each sensing node;
determining if the screen signal information includes one or more sensing node locations with corresponding values indicative of a first local maximum value having a value less than a first threshold value and greater than a second threshold value;
determining if the screen signal information includes a first sensing node location within a defined proximity to the one or more sensing node locations with corresponding values indicative of a first local maximum, the first sensing node location being in a region of sensing node locations, wherein each value of each sensing node location in the region is less than a third threshold value that is less than or equal to the second threshold value, and each sensing node location in the region is adjacent to another sensing node location in the region; and
determining that moisture is in contact with the touch screen at the one or more sensing node locations with corresponding values indicative of a first local maximum based on at least the inclusion of the first sensing node location.

10. The method of claim 9 , wherein the defined proximity is based on at least a distance threshold.

11. The method of claim 9 , further comprising determining that moisture is in contact with the touch screen at sensing node locations associated with the region based on at least the inclusion of the first sensing node location.

12. The method of claim 9 , wherein the first threshold is less than a lowest value associated with a finger touch for the screen signal information.

13. The method of claim 9 , wherein the second threshold signal value is greater than a highest value associated with noise for the screen signal information.

14. The method of claim 9 , further comprising determining if the screen signal information includes one or more sensing node locations with corresponding values indicative of a second local maximum value, the second local maximum value being less than the first threshold value and greater than the second threshold value.

15. The method of claim 14 , further comprising determining if the screen signal information includes a second sensing node location within the defined proximity to the one or more sensing node locations with corresponding values indicative of a second local maximum, the second sensing node location being in the region.

16. The method of claim 15 , wherein determining that moisture is in contact with the touch screen at the one or more sensing node locations with corresponding values indicative of a first local maximum is further based on at least the inclusion of the second sensing node location.

17. A touch screen apparatus, comprising:
means for receiving touch signals from a plurality of sensing nodes of a touch screen, each sensing node being configured to sense a screen touch event and produce a corresponding touch signal;
means for producing screen signal information comprising each location of each sensing node and a corresponding value representative of the received touch signal at each location of each sensing node;
means for determining if the screen signal information includes one or more sensing node locations with corresponding values indicative of a first local maximum value having a value less than a first threshold value and greater than a second threshold value;
means for determining if the screen signal information includes a first sensing node location within a defined proximity to the one or more sensing node locations with corresponding values indicative of a first local maximum, the first sensing node location being in a region of sensing node locations, wherein each value of each sensing node location in the region is less than a third threshold value that is

Assignees

• Qualcomm Inc

Inventors

• Ng Teresa Ka Ki
• Huang William Yee-Ming
• Gao Qiang
• Wong Hsun Wei David
• Law Carol King Mui
• Tilak Raghukul
• Wang Rex
• Jalil Suhail
• Ahmed Mohamed Imtiaz

Classifications

• G06F2203/04101

  2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup · CPC title

• G06F3/0418 Primary

  for error correction or compensation, e.g. based on parallax, calibration or alignment · CPC title

• G06F3/044

  by capacitive means · CPC title

• G06F3/04186 Primary

  Touch location disambiguation · CPC title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title