Noise reduction method and system of capacitive multi-touch panel

• US 20140132556A1
• Filed: 10/30/2013
• Published: 05/15/2014
• Est. Priority Date: 11/09/2012
• Status: Active Grant

• Current Assignee: FocalTech Systems Co.,Ltd
• Original Assignee: Orise Technology Co., Ltd (FocalTech Systems Co.,Ltd)
• Inventors: HUANG, Hsin-Mao, KUNG, Chih-Hung, WANG, Hsin-Hao
• Granted Patent: US 9,170,681 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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 noise reduction system includes a driving device, a sensing device, a first switch, a second switch, and a controller. The driving device has a plurality of drivers for generating touch driving signals. The sensing device has a plurality of sensors for detecting whether there is an external object approached and generating touch sensing signals. The first switch is provided for electrically connecting the plurality of drivers and the plurality of sensors to the capacitive touch panel. The second switch is provided for electrically connecting the plurality of drivers and the plurality of sensors to the capacitive touch panel. The controller configures the first switch and the second switch to perform a first direction driving and second direction sensing, and configuring the first switch and the second switch to perform a second direction driving and first direction sensing.

Claims

1. A noise reduction system for a capacitive touch panel, the capacitive touch panel including M first conductor lines and N second conductor lines arranged along a first direction and a second direction, respectively, where M and N are integer greater than 1 respectively, the noise reduction system comprising:

a driving device, having a plurality of drivers, for generating touch driving signals in touch sensing operation;

a sensing device, having a plurality of sensors, for detecting whether there is an external object approached according to the touch driving signals, and generating touch sensing signals;

a first switch, connected to the driving device, the sensing device, and the capacitive touch panel, for electrically connecting the plurality of drivers of the driving device and the plurality of sensors of the sensing device to the capacitive touch panel;

a second switch, connected to the driving device, the sensing device, and the capacitive touch panel, for electrically connecting the plurality of drivers of the driving device and the plurality of sensors of the sensing device to the capacitive touch panel; and

a controller, connected to the driving device, the sensing device, the first switch, and the second switch, for configuring the first switch and the second switch to perform a first direction driving and second direction sensing, and configuring the first switch and the second switch to perform a second direction driving and first direction sensing.

2. The noise reduction system as claimed in claim 1, wherein during a first time interval, the controller configures the first switch for electrically connecting the plurality of drivers of the driving device to the M first conductor lines of the capacitive touch panel, and configures the second switch for electrically connecting the plurality of sensors of the sensing device to the N second conductor lines of the capacitive touch panel, thereby proceeding with the first direction driving and second direction sensing and generating a first sensing image data.

3. The noise reduction system as claimed in claim 2, wherein during a second time interval, the controller configures the first switch for electrically connecting the plurality of drivers of the driving device to the N second conductor lines of the capacitive touch panel, and configures the second switch for electrically connecting the plurality of sensors of the sensing device to the M first conductor lines of the capacitive touch panel, thereby proceeding with the second direction driving and first direction sensing and generating a second sensing image data.

4. The noise reduction system as claimed in claim 1, wherein the first direction is vertical with the second direction.

5. The noise reduction system as claimed in claim 3, wherein the controller has a register unit, which includes a,first storage block, a second storage block and a third storage block.

6. The noise reduction system as claimed in claim 5, wherein the first storage block stores an initialization sensing image data during the capacitive touch panel initialized, the second storage block stores the first sensing image data during the first time interval, and the third storage block stores the first sensing image data during the second time interval.

7. The noise reduction system as claimed in claim 6, wherein each of the initialization sensing image data, the first sensing image data and the second sensing image data has M*N data respectively.

8. The noise reduction system as claimed in claim 3, wherein the controller performs a transpose operation to the data obtained from proceeding with the second direction driving and first direction sensing during the second time interval, so as to obtain the second sensing image data.

9. The noise reduction system as claimed in claim 6, wherein the controller determines sensing image data of the capacitive touch panel based on the initialization sensing image data, the first sensing image data and the second sensing image data.

10. The noise reduction system as claimed in claim 9, wherein when an absolute value of difference between the first sensing image data and the initialization sensing image data at corresponding position is smaller than or equal to an absolute value of difference between the second sensing image data at the corresponding position and the initialization sensing image data at the corresponding position, the controller configures the sensing image data at the corresponding position of the capacitive touch panel as the first sensing image data and, otherwise the controller configures the sensing image data at the corresponding position of the capacitive touch panel as the second sensing image data.

11. The noise reduction system as claimed in claim 10, wherein the controller determines the sensing image data of the capacitive touch panel based on the following equation:

12. A noise reduction method for a capacitive touch panel, the capacitive touch panel having M first conductor lines and N second conductor lines arranged along a first direction and a second direction, respectively, where M and N are each an integer greater than 1, the noise reduction method comprising the steps of:

(A) capturing an initialization sensing image data from the capacitive touch panel;

(B) during a first time interval, a controller configuring a first switch and a second switch to perform a first direction driving and second direction sensing thereby obtaining a first sensing image data;

(C) during a second time interval, the controller configuring the first switch and the second switch to perform a second direction driving and first direction sensing thereby obtaining a second sensing image data; and

(D) the controller determining sensing image data from the capacitive touch panel based on the initialization sensing image data, the first sensing image data and the second sensing image data.

13. The noise reduction method as claimed in claim 12, wherein in step (B), the controller configures the first switch for electrically connecting a plurality of drivers of a driving device to the M first conductor lines from the capacitive touch panel, and configuring the second switch for electrically connecting a plurality from sensors of a sensing device to the N second conductor lines of the capacitive touch panel, so as to perform the first direction driving and second direction sensing

14. The noise reduction method as claimed in claim 13, wherein in step (C), the controller configures the first switch for electrically connecting the plurality of drivers of the driving device to the N second conductor lines from the capacitive touch panel, and configures the second switch for electrically connecting the plurality of sensors of the sensing device to the M first conductor lines from the capacitive touch panel, so as to perform the second direction driving and first direction sensing.

15. The noise reduction method as claimed in claim 12, wherein the initialization sensing image data, the first sensing image data and the second sensing image data have M×

N data respectively.

16. The noise reduction method as claimed in claim 14, wherein when an absolute value of difference between the first sensing image data and the initialization sensing image data at corresponding point is smaller than or equal to an absolute value of difference between the second sensing image data at the corresponding position and the initialization sensing image data at the corresponding position, the controller configures the sensing image data at corresponding position of the capacitive touch panel as the first sensing image data and, otherwise the controller configures sensing image data at the corresponding position of the capacitive touch panel as the second sensing image data.

17. The noise reduction method as claimed in claim 15, wherein the controller determines the sensing image data of the capacitive touch panel based on the following equation: