Touch screen driver including out-of-phase driving signals simultaneously supplied to adjacent TX lines for reducing noise from a display panel, and method for driving the same

• US 9,619,073 B2
• Filed: 09/25/2012
• Issued: 04/11/2017
• Est. Priority Date: 09/27/2011
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Cho, Jiho, Bae, Jungtae, Shin, Myungho
• Primary Examiner(s): Haley, Joseph
• Assistant Examiner(s): Kiyabu, Karin
• Application Number:
  US13/626,287
• Publication Number:
  US 20130076675A1
• Time in Patent Office: 1,659 Days
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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 touch screen driver and method for driving the same are disclosed. The touch screen driver includes a Tx driving circuit which sequentially supplies a pair of out-of-phase composed of a first driving signal and a second driving signal which has a phase difference of 180° with respect to the first driving signal and the second driving signal driving signals to Tx lines, wherein the first signal and the second signal are simultaneously supplied to the adjacent Tx lines, respectively; and an Rx driving circuit which samples a charge of the touch sensor received through the Rx lines coupled with the Tx lines and converts the sampled charge into digital data.

Claims

1. A touch screen driver, comprising:

a touch screen including;

transmission (Tx) lines,

reception (Rx) lines crossing the Tx lines, and

touch sensors between the Tx lines and the Rx lines;

a Tx driving circuit configured to sequentially supply a pair of out-of-phase driving signals including a first driving signal and a second driving signal, which has a phase difference of 180°

with respect to the first driving signal, to the Tx lines, the first driving signal and the second driving signal being simultaneously respectively supplied to only a first and a second Tx line adjacent to each other, the first driving signal and the second driving signal subsequently being simultaneously respectively supplied to only the second and a third Tx line, the third Tx line being different from the first Tx line, the first driving signal and the second driving signal having a same frequency; and

an Rx driving circuit configured to;

sample a charge of the touch sensor received through the Rx lines coupled with the Tx lines;

convert the sampled charge into digital data;

output initial digital data obtained as an initial scanning result of the touch screen; and

output digital data obtained as a scanning result of the touch screen as normal data when a touch input of the touch screen is generated.

2. The touch screen driver of claim 1, wherein the Tx driving circuit is configured to generate the second driving signal by shifting a phase of the first driving signal as much as 180°

.

3. The touch screen driver of claim 1, further comprising:

a data compensator configured to generate final touch raw data based on the normal data and reference data including the initial digital data and dummy data having a predetermined digital value; and

a touch controller configured to;

control operation timings of the Tx driving circuit and the Rx driving circuit;

analyze the final touch raw data using a previously set touch recognition algorithm; and

estimate a coordinate value of a touch input location.

4. The touch screen driver of claim 3, wherein the data compensator is configured to:

produce compensation data with values obtained by subtracting the reference data from the normal data; and

add a value of the compensation data to an integration result of the compensation data to generate the final touch raw data.

5. The touch screen driver of claim 4, wherein the data compensator is configured to:

calculate a difference between vertically adjacent first and second compensation data in the compensation data, which is vertically arranged along a Y-axis direction of the touch screen, as a first integration result;

subtract the first integration result from third compensation data to calculate a second integration result; and

accumulate a difference between the adjacent compensation data.

6. The touch screen driver of claim 5, wherein the predetermined digital value of each dummy data is set to zero.

7. The touch screen driver of claim 6, wherein:

the compensation value is independently determined in each Rx line;

the same i^th compensation value is added to integration results arranged along an i^th Rx line, where “

i”

is a natural number; and

when the i^th compensation value is added to each of the integration results arranged along the i^th Rx line, a minimum value of the integration results arranged along the i^th Rx line is changed to zero.

8. The touch screen driver of claim 1, wherein, after the first driving signal and the second driving signal are supplied to only the second and the third Tx line, the first driving signal and the second driving signal are subsequently supplied to only the third and a fourth Tx line, the fourth Tx line being different from the first and second Tx lines.

9. A method for driving a touch screen driver including a touch screen including transmission (Tx) lines, reception (Rx) lines crossing the Tx lines, and touch sensors formed between the Tx lines and the Rx lines, the method comprising:

sequentially supplying a pair of out-of-phase driving signals including a first driving signal and a second driving signal, which has a phase difference of 180°

with respect to the first driving signal, to the Tx lines, the first driving signal and the second driving signal being simultaneously respectively supplied to only a first and a second Tx line adjacent to each other, the first driving signal and the second driving signal subsequently being simultaneously respectively supplied to only the second and a third Tx line, the third Tx line being different from the first Tx line, the first driving signal and the second driving signal having a same frequency;

sampling a charge of the touch sensor received through the Rx lines coupled with the Tx lines; and

converting the sampled charge into digital data,

wherein the converting of the sampled charge into the digital data includes;

generating initial digital data obtained as an initial scanning result of the touch screen; and

generating digital data obtained as a scanning result of the touch screen as normal data when a touch input of the touch screen is generated.

10. The method of claim 9, further comprising:

generating final touch raw data based on the normal data and reference data including the initial digital data and dummy data having a predetermined digital value;

analyzing the final touch raw data using a previously set touch recognition algorithm; and

estimating a coordinate value of a touch input location.

11. The method of claim 10, wherein the generating of the final touch raw data includes:

generating compensation data with values obtained by subtracting the reference data from the normal data; and

adding the value of the compensation data to an integration result of the compensation data to generate the final touch raw data.

12. The method of claim 11, wherein the adding of the compensation value to the integration result of the compensation data to generate the final touch raw data includes:

calculating a difference between vertically adjacent first and second compensation data in the compensation data, which is vertically arranged along a Y-axis direction of the touch screen, as a first integration result;

subtracting the first integration result from third compensation data to calculate a second integration result; and

accumulating a difference between the adjacent compensation data.

13. The method of claim 12, wherein the predetermined digital value of each dummy data is set to zero.

14. The method of claim 13, wherein:

the compensation value is independently determined in each Rx line;

the same i^th compensation value is added to integration results arranged along an i^th Rx line, where “

i”

is a natural number; and

when the i^th compensation value is added to each of the integration results arranged along the i^th Rx line, a minimum value of the integration results arranged along the i^th Rx line is changed to zero.

15. The method of claim 9, further comprising, after the first driving signal and the second driving signal are supplied to only the second and the third Tx line, the first driving signal and the second driving signal are subsequently supplied to only the third and a fourth Tx line, the fourth Tx line being different from the first and second Tx lines.