Method and device for reducing poor linearity in location detection

• US 9,569,043 B2
• Filed: 12/26/2013
• Issued: 02/14/2017
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Yeh, Shang-Tai
• Primary Examiner(s): Giesy, Adam R
• Assistant Examiner(s): Kiyabu, Karin
• Application Number:
  US14/140,826
• Publication Number:
  US 20140184564A1
• Time in Patent Office: 1,146 Days
• US Class Current: 1/1
• 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

The changes of capacitances of a plurality of detecting locations on a touch screen are detected for determining a profile corresponding to each external object approaching or touching the touch screen. Then the location of each external object is generated separately by two or four values in the corresponding profile.

Claims

1. The method for location detection of a touch screen comprising:

detecting changes in capacitances of a plurality of detecting locations on the touch screen, wherein each change in capacitances corresponds to a coordinate; and

determining a profile corresponding to each external object based on the changes in capacitances of the detecting locations on the touch screen, and generating a coordinate data of each external object based on four values in the corresponding profile;

wherein, the coordinate data is as follows;

2. The method for location detection of claim 1, wherein C1 and C3 are values immediately preceding and following the largest value, respectively, and C2 and C4 are values immediately preceding and following the second largest value, respectively.

3. The method for location detection of claim 1, wherein C2 and C4 are values immediately preceding and following the largest value, respectively, and C1 and C3 are values immediately preceding and following the second largest value, respectively.

4. The method for location detection of claim 1, wherein generating the coordinate data includes:

calculating a first centroid coordinate based on a value immediately preceding the largest value and a value immediately following the largest value in the profile of each external object, and setting the first centroid coordinate as the coordinate corresponding to the largest value;

calculating a second centroid coordinate based on a value immediately preceding the second value and a value immediately following the second largest value in the profile of each external object, and setting the second centroid coordinate as the coordinate corresponding to the second largest value; and

calculating the coordinate data based on the largest value and the second largest value in the profile of each external object, wherein the coordinate data is calculated based on the first and the second centroid coordinates.

5. The method for location detection of claim 4, wherein the first centroid coordinate is (C1×

X1+C3×

X3)/(C1+C3), and the second centroid coordinate is (C2×

X2+C4×

X4)/(C2+C4), wherein X1, X2, X3 and X4 are the coordinates for C1, C2, C3 and C4, respectively, and C1, C2 and C3 correspond to the value immediately preceding the largest value, the largest value, and the value immediately following the largest value in the profile of each external object, respectively, and C2, C3 and C4 correspond to the value immediately preceding the second largest value, the second largest value, and the value immediately following the second largest value in the profile of each external object, respectively.

6. The method for location detection of claim 4, wherein the first centroid coordinate is (C2×

X2+C4×

X4)/(C2+C4), and the second centroid coordinate is (C1×

X1+C3×

X3)/(C1+C3), wherein X1, X2, X3 and X4 are the coordinates for C1, C2, C3 and C4, respectively, and C1, C2 and C3 correspond to the value immediately preceding the largest value, the largest value, and the value immediately following the largest value in the profile of each external object, respectively, and C2, C3 and C4 correspond to the value immediately preceding the second largest value, the second largest value, and the value immediately following the second largest value in the profile of each external object, respectively.

7. A device for location detection of a touch screen comprising:

a detecting unit for detecting changes in capacitances of a plurality of detecting locations on the touch screen, wherein each change in capacitances corresponds to a coordinate; and

a control unit for determining a profile corresponding to each external object based on the changes in capacitances of the detecting locations on the touch screen, and generating a coordinate data of each external object is based on four values in the corresponding profile;

wherein, the coordinate data is as follows;

8. The device for location detection of claim 7, wherein C1 and C3 are values immediately preceding and following the largest value, respectively, and C2 and C4 are values immediately preceding and following the second largest value, respectively.

9. The device for location detection of claim 7, wherein C2 and C4 are values immediately preceding and following the largest value, respectively, and C1 and C3 are values immediately preceding and following the second largest value, respectively.