Display device and method for driving the same

• US 10,275,089 B2
• Filed: 12/28/2015
• Issued: 04/30/2019
• Est. Priority Date: 09/30/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Younggyu, Lee, Byounggwan, Jang, Yoonnara
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Gyawali, Bipin
• Application Number:
  US14/981,087
• Publication Number:
  US 20170090673A1
• Time in Patent Office: 1,219 Days
• Field of Search: None
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user

Abstract

A display device includes a deviation compensating circuit to receive a feedback touch driving signal from a sensor line connected to one of a plurality of touch sensor, receive a first feedback AC (alternating current) signal from a data line connected to one of a plurality of pixels, receive a second feedback AC signal from a gate line connected to the pixels, detect a phase deviation and an amplitude deviation between the feedback touch driving signal and the first and the second feedback AC signals, and generate a compensation touch driving signal, a first compensation AC signal, and a second compensation AC signal for compensating for the phase deviation and the amplitude deviation.

Claims

1. A display device comprising:

a display panel including a plurality of pixels for displaying an input image and a plurality of touch sensors for sensing a touch input;

a deviation compensating circuit to receive a feedback touch driving signal from a sensor line connected to one of the plurality of touch sensors, receive a first feedback alternating current (AC) signal from a data line connected to one of the plurality of pixels, receive a second feedback AC signal from a gate line connected to one of the plurality of pixels, and generate a compensation touch driving signal, a first compensation AC signal, and a second compensation AC signal for compensating;

a touch sensor driver to supply the compensation touch driving signal to the sensor line during a touch sensor driving period, in which the touch input is sensed; and

a display driver to supply the first compensation AC signal to the data line and supply the second compensation AC signal to the gate line during the touch sensor driving period,

wherein the deviation compensating circuit comprises;

a controller to detect a phase deviation and an amplitude deviation between the feedback touch driving signal and the first and the second feedback AC signals and output a first compensation control signal for compensating for the phase deviation and a second compensation control signal for compensating for the amplitude deviation;

a pulse width modulation (PWM) generator to output a first PWM signal, a second PWM signal, and a third PWM signal, each of which has a compensated phase in response to the first compensation control signal; and

a touch power integrated circuit (IC) to produce the compensation touch driving signal based on the first PWM signal, produce the first compensation AC signal based on the second PWM signal, produce the second compensation AC signal based on the third PWM signal, and adjust a maximum voltage of each of the compensation touch driving signal, the first compensation AC signal, and the second compensation AC signal in response to the second compensation control signal.

2. The display device of claim 1, wherein the deviation compensating circuit further comprises:

a phase detector to detect phases of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal;

an amplitude detector to detect amplitudes of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal.

3. The display device of claim 2, wherein the phase detector comprises:

a positive clamper to clamp each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal in a positive direction;

a voltage divider to downscale an amplitude of the clamped signal;

a digital-to-analog converter (DAC) to produce a low reference voltage and a high reference voltage for measuring a rising time;

a comparator to compare the low reference voltage and the high reference voltage with the downscaled signal and output a rising start time point and a rising end time point of the downscaled signal; and

a rising time detector to detect a period of time between the rising start time point and the rising end time point as a rising time.

4. The display device of claim 1, wherein only when a rising time of the feedback touch driving signal exceeds a previously set critical value, the controller produces the first compensation control signal for compensating for the phase deviation.

5. The display device of claim 4, wherein the first compensation control signal includes a first phase control value for compensating for a rising time deviation between the feedback touch driving signal and the first feedback AC signal and a second phase control value for compensating for a rising time deviation between the feedback touch driving signal and the second feedback AC signal.

6. The display device of claim 2, wherein the amplitude detector comprises:

a positive clamper to clamp each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal in a positive direction;

a voltage divider to downscale an amplitude of the clamped signal;

a half wave rectifier to convert the downscaled signal into an analog direct current (DC) voltage; and

an analog-to-digital converter (ADC) to convert the analog DC voltage into a digital DC voltage.

7. The display device of claim 6, wherein the controller compares the digital DC voltage of each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal with a reference value and outputs the second compensation control signal for compensating for the amplitude deviation.

8. A method for driving a display device including a display panel, including a plurality of pixels for displaying an input image and a plurality of touch sensors for sensing a touch input, the method comprising:

receiving a feedback touch driving signal from a sensor line connected to one of the plurality of touch sensors, receiving a first feedback alternating current (AC) signal from a data line connected to one of the plurality of pixels, receiving a second feedback AC signal from a gate line connected to one of the plurality of pixels;

generating a compensation touch driving signal, a first compensation AC signal, and a second compensation AC signal; and

supplying the compensation touch driving signal to the sensor line during a touch sensor driving period, in which the touch input is sensed, supplying the first compensation AC signal to the data line during the touch sensor driving period, and supplying the second compensation AC signal to the gate line during the touch sensor driving period,

wherein the generating of the compensation touch driving signal, the first compensation AC signal, and the second compensation AC signal comprises;

detecting a phase deviation and an amplitude deviation between the feedback touch driving signal and the first and the second feedback AC signals and outputting a first compensation control signal for compensating for the phase deviation and a second compensation control signal for compensating for the amplitude deviation;

outputting a first pulse width modulation (PWM) signal, a second PWM signal, and a third PWM signal, each of which has a compensated phase in response to the first compensation control signal; and

generating the compensation touch driving signal based on the first PWM signal, generating the first compensation AC signal based on the second PWM signal, generating the second compensation AC signal based on the third PWM signal, and adjusting a maximum voltage of each of the compensation touch driving signal, the first compensation AC signal, and the second compensation AC signal in response to the second compensation control signal.

9. The method of claim 8, wherein the generating of the compensation touch driving signal, the first compensation AC signal, and the second compensation AC signal further comprises:

detecting phases of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal;

detecting amplitudes of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal.

10. The method of claim 9, wherein the detecting of the phases of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal comprises:

clamping each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal in a positive direction;

downscaling an amplitude of the clamped signal;

producing a low reference voltage and a high reference voltage for measuring a rising time;

comparing the low reference voltage and the high reference voltage with the downscaled signal and outputting a rising start time point and a rising end time point of the downscaled signal; and

detecting a period of time between the rising start time point and the rising end time point as a rising time.

11. The method of claim 8, wherein only when a rising time of the feedback touch driving signal exceeds a previously set critical value, the first compensation control signal is output.

12. The method of claim 11, wherein the first compensation control signal includes a first phase control value for compensating for a rising time deviation between the feedback touch driving signal and the first feedback AC signal and a second phase control value for compensating for a rising time deviation between the feedback touch driving signal and the second feedback AC signal.

13. The method of claim 9, wherein the detecting of the amplitudes of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal comprises:

clamping each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal in a positive direction;

downscaling an amplitude of the clamped signal;

converting the downscaled signal into an analog direct current (DC) voltage; and

converting the analog DC voltage into a digital DC voltage.

14. The method of claim 13, wherein the detecting of the amplitudes of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal includes comparing the digital DC voltage of each of the feedback touch driving signal, the first feedback AC signal, and the second feedback AC signal with a reference value to output the second compensation control signal for compensating for the amplitude deviation.