METHOD OF REDUCING COMPUTATION OF WATER TOLERANCE BY PROJECTING TOUCH DATA

• US 20130278543A1
• Filed: 04/23/2012
• Published: 10/24/2013
• Est. Priority Date: 04/23/2012
• Status: Active Grant

• Current Assignee: Silicon Integrated Systems Corporation (Silicon Integrated Systems Corporation Taiwan)
• Original Assignee: Silicon Integrated Systems Corporation (Silicon Integrated Systems Corporation Taiwan)
• Inventors: Hsu, Jih-Ming, Kuo, Chin-Hua
• Granted Patent: US 8,976,146 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means
• 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 method of reducing computation of water tolerance by projecting touch data is disclosed, targeting the handheld devices. The method targets first at obtaining a difference array, followed by extracting minimum values of rows and columns of the difference array to obtain a row projection list and a column projection list respectively. By repeated implementing of mutual capacitance detection, ghost water blocks can be wiped out from the multiple water blocks. Once integrating with a local spatial boundary detection algorithm, the sensed signals of intended input located within a rectangular water block yet beyond a real water block are consequently detected. The computational algorithm of the water tolerance of this invention is successfully built into the touch panel controller due to its substantially reduced computation.

Claims

1. A method of reducing computation of water tolerance by projecting touch data, the method comprising steps of:

obtaining capacitance raw data of a sensing array having row sensing lines and column sensing lines;

comparing the capacitance raw data with reference raw data to obtain a difference array;

obtaining a row projection list by extracting minimum values of rows the difference array; and

obtaining a column project list by extracting minimum values of columns of the difference array.

2. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, wherein the current raw data of the sensing array are obtained by measuring self-capacitances of the respective row sensing lines and the respective column sensing lines.

3. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, wherein the current raw data of the sensing array are obtained by measuring mutual capacitances between the row sensing lines and the column sensing lines.

4. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, wherein the reference raw data comprises a capacitance matrix computed by a statistic model under a condition that no touch or water block event occurs on the sensing array.

5. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 4, wherein the reference raw data is computed by using a static calibration procedure.

6. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 4, wherein the reference raw data is computed by using a dynamic calibration procedure.

7. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, further comprising a step of determining at least one rectangular water block by the row projection list and the column projection list.

8. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 7, wherein the step of determining at least one rectangular water block by the row projection list and the column projection list is to compare the row projection list with a first water threshold and compare the column projection list with a second water threshold respectively to form a row water mask and a column water mask to determine an extent of the water block.

9. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 8, wherein the corresponding row water mask or column water mask equals to 1 if a sensed signal of a sensing line in the water block lowers than the water threshold;

otherwise, the corresponding row water mask or column water mask equals to 0 if a sensed signal of a sensing line in the water block exceeds the water threshold.

10. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 9, wherein if the number of the adjoined row sensing lines in the water block is greater than a row-threshold and the number of the adjoined column sensing lines in the water block is greater than a column-threshold, the sensed signals generated in the water block are filtered out or neglected.

11. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 9, wherein the number of the adjoined row sensing lines in the water block multiplied by the number of the adjoined column sensing lines in the water block is greater than an area-threshold, the sensed signals generated in the water block are filtered out or neglected.

12. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, further comprising a step of filtering out ghost water blocks from the rectangular water blocks one after the other, which is accomplished by filtering out ghost water blocks from the plurality of water blocks by means of mutual capacitance detection.

13. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, further comprising a step of preventing dynamic calibration on the real water blocks, which prevents the real water blocks from being mistaken for sensed signals or palm blocks when the water is dry.

14. The method of reducing computation of water tolerance by projecting touch data as claimed in claim 1, further comprising:

detecting the sensed signals fallen within the rectangular water blocks yet beyond real water blocks by means of combining a local spatial boundary detection algorithm.