Method and System for Processing Signals of Touch Panel

• US 20120206399A1
• Filed: 03/24/2011
• Published: 08/16/2012
• Est. Priority Date: 02/10/2011
• Status: Abandoned Application

• Current Assignee: Alcor Micro Corp.
• Original Assignee: Alcor Micro Corp.
• Inventors: Wang, Chuen-Heng, Wu, Chien-Hsien
• Application Number:
  US13/071,197
• Publication Number:
  US 20120206399A1
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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 and system for processing the signals of a touch panel are provided. Therein, the capacitive values of each sensor on the touch panel are successively taken during a period of time. Then, the average capacitive value of each sensor is calculated for computing estimated touch point coordinates. The distance between each two sets of such coordinates sensed respectively at two sensing time points is calculated. If a distance thus calculated is less than a predetermined distance, the two sets of estimated touch point coordinates corresponding to the distance are defined as valid touch point coordinates. If a series of estimated touch point coordinates are successively defined as valid touch point coordinates for a predetermined number of times, the touch point corresponding to each set of valid touch point coordinates in the series is defined as a valid touch point. Thus, the precision of touch point determination is enhanced.

Claims

1. A method for processing signals of a touch panel, wherein the touch panel comprises a plurality of sensors, the method comprising the steps of:

(a) taking capacitive values of each said sensor of the touch panel successively during a period of time;

(b) calculating an average capacitive value of each said sensor for the period of time, wherein, for each said sensor, the average capacitive value is calculated by removing at least one relatively large said capacitive value and at least one relatively small said capacitive value from the capacitive values taken and then taking average of remaining said capacitive values;

(c) reading the average capacitive value of each said sensor so as to calculate and generate at least one set of estimated touch point coordinates;

(d) repeating the steps (a) to (c) so as to obtain at least one set of said estimated touch point coordinates at each of two consecutive sensing time points, and calculating a distance between each two sets of said estimated touch point coordinates obtained respectively at the two sensing time points;

(e) determining whether each said distance is less than a predetermined distance, wherein if one said distance is greater than the predetermined distance, the two sets of estimated touch point coordinates corresponding to the distance are defined as invalid touch point coordinates;

wherein if one said distance is less than the predetermined distance, the two sets of estimated touch point coordinates corresponding to the distance are defined as valid touch point coordinates; and

(f) repeating the step (e), and if a series of said estimated touch point coordinates are defined as said valid touch point coordinates successively for a predetermined number of times, defining a touch point corresponding to each set of said valid touch point coordinates in the series as a valid touch point.

2. The method of claim 1, wherein the period of time in the step (a) includes four sampling cycles such that four said capacitive values are successively taken of each said sensor of the touch panel, and wherein the step (b) comprises removing one relatively large said capacitive value and one relatively small said capacitive value from the four capacitive values of each said sensor and then taking average of the remaining two capacitive values of each said sensor so as to produce the average capacitive value of each said sensor.

3. The method of claim 1, wherein the period of time in the step (a) includes eight sampling cycles such that eight said capacitive values are successively taken of each said sensor of the touch panel, and wherein the step (b) comprises removing two relatively large said capacitive values and two relatively small said capacitive values from the eight capacitive values of each said sensor and then taking average of the remaining four capacitive values of each said sensor so as to produce the average capacitive value of each said sensor.

4. The method of claim 1, wherein the predetermined distance is a distance across three said sensors of the touch panel.

5. The method of claim 1, wherein the predetermined number of times is four.

6. A system for processing signals of a touch panel, wherein the touch panel comprises a plurality of sensors, the system comprising:

a sampling module for taking capacitive values of each said sensor of the touch panel successively during a period of time;

a processing module for calculating an average capacitive value of each said sensor for the period of time, wherein, for each said sensor, the average capacitive value is calculated by removing at least one relatively large said capacitive value and at least one relatively small said capacitive value from the capacitive values taken and then taking average of remaining said capacitive values;

a conversion module for reading the average capacitive value of each said sensor and, by calculation, generating at least one set of estimated touch point coordinates;

a calculation module for reading at least one set of said estimated touch point coordinates at each of two sensing time points and calculating a distance between each two sets of said estimated touch point coordinates read respectively at the two sensing time points; and

a determination module for determining whether each said distance is greater than a predetermined distance, wherein if one said distance is greater than the predetermined distance, the two sets of estimated touch point coordinates corresponding to the distance are defined as invalid touch point coordinates;

if one said distance is less than the predetermined distance, the two sets of estimated touch point coordinates corresponding to the distance are defined as valid touch point coordinates; and

if a series of said estimated touch point coordinates are defined as said valid touch point coordinates successively for a predetermined number of times, a touch point corresponding to each set of said valid touch point coordinates in the series is defined as a valid touch point.

7. The system of claim 6, wherein the period of time includes four sampling cycles such that four said capacitive values are successively taken of each said sensor of the touch panel, and wherein the average capacitive value of each said sensor is calculated by removing one relatively large said capacitive value and one relatively small said capacitive value from the four capacitive values of each said sensor and then taking average of the remaining two capacitive values of each said sensor.

8. The system of claim 6, wherein the period of time includes eight sampling cycles such that eight said capacitive values are successively taken of each said sensor of the touch panel, and wherein the average capacitive value of each said sensor is calculated by removing two relatively large said capacitive values and two relatively small said capacitive values from the eight capacitive values of each said sensor and then taking average of the remaining four capacitive values of each said sensor.

9. The system of claim 6, wherein the predetermined distance is a distance across three said sensors of the touch panel.

10. The system of claim 6, wherein the predetermined number of times is four.