Source output voltage compensation for display noise

Patent metadata

Field	Value
Publication number	US-11467694-B2
Application number	US-202117243192-A
Country	US
Kind code	B2
Filing date	Apr 28, 2021
Priority date	Dec 14, 2020
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

An input-display device includes a display screen disposed on a display substrate, the display screen including a multitude of display pixels. The input-display device further includes a multitude of capacitive sensing electrodes for capacitive sensing in a sensing region of the display screen. The input-display device also includes a source driver circuit configured to generate a data voltage for driving a pixel circuit associated with one display pixel of the multitude of display pixels and determine a timing for a compensatory modulation of the data voltage. The timing is determined using a sensing waveform of the capacitive sensing. The source driver circuit is also configured to determine an amplitude of the compensatory modulation, generate a modulated data voltage by applying the compensatory modulation to the data voltage, and drive the pixel circuit using the modulated data voltage.

First claim

What is claimed is:

1. An input-display device, comprising:
a display screen disposed on a display substrate, the display screen comprising a plurality of display pixels;
a plurality of capacitive sensing electrodes for capacitive sensing in a sensing region of the display screen; and
a source driver circuit configured to:
generate a data voltage for driving a pixel circuit associated with one display pixel of the plurality of display pixels;
determine a timing for a compensatory modulation of the data voltage,
wherein the timing is determined using a sensing waveform of the capacitive sensing;

determine an amplitude of the compensatory modulation, wherein the amplitude of the compensatory modulation is based at least in part on measured capacitances in the input display device and the sensing waveform, wherein different amplitudes of the compensatory modulation are used depending on the sensing waveform;
generate a modulated data voltage by applying the compensatory modulation to the data voltage; and
drive the pixel circuit using the modulated data voltage.

2. The input-display device of claim 1 , further comprising:
a touch and display driver integration (TDDI) circuit comprising:
the source driver circuit, wherein the source driver circuit is configured to generate the data voltage based on a processed image signal, and
an analog frontend for the capacitive sensing, the analog frontend interfacing with the plurality of capacitive sensing electrodes to obtain a plurality of touch signals, wherein the analog frontend generates the sensing waveform.

3. The input-display device of claim 2 ,
wherein the TDDI circuit further comprises:
an image processing circuit configured to generate the processed image signal based on a received image signal obtained from a host application processor, and
a touch processing circuit configured to generate a touch output signal by processing the plurality of touch signals.

4. The input-display device of claim 2 , wherein determining the timing for the compensatory modulation comprises:
obtaining, the timing from the analog frontend.

5. The input-display device of claim 1 , wherein the amplitude of the compensatory modulation is selected to, at least partially, compensate for an artifact on the data voltage at the pixel circuit, the artifact associated with the sensing waveform coupled onto the data voltage via a parasitic capacitance.

6. The input-display device of claim 1 ,
wherein applying the compensatory modulation to the data voltage comprises:
additively superimposing the compensatory modulation on the data voltage.

7. The input-display device of claim 1 ,
wherein the source driver is further configured to perform a gamma transformation to obtain the data voltage from a gray level specified by input image data, and
wherein performing the gamma transformation comprises applying the compensatory modulation as an amplitude increment to the data voltage.

8. The input-display device of claim 1 , wherein the display screen is an OLED display screen.

9. The input-display device of claim 1 ,
wherein the display screen comprises a display cathode, and
wherein the display cathode is one of the plurality of capacitive sensing electrodes.

10. A touch and display driver integration (TDDI) circuit, the TDDI circuit comprising:
a source driver circuit configured to:
generate a data voltage for driving a pixel circuit associated with a pixel of a display screen, based on a processed image signal;
determine a timing for a compensatory modulation of the data voltage,
wherein the timing is determined using a sensing waveform of a capacitive sensing;

determine an amplitude of the compensatory modulation, wherein the amplitude of the compensatory modulation is based at least in part on measured capacitances in the input display device and the sensing waveform, wherein different amplitudes of the compensatory modulation are used depending on the sensing waveform;
generate a modulated data voltage by applying the compensatory modulation to the data voltage; and
drive the pixel circuit using the modulated data voltage.

11. The TDDI circuit of claim 10 , further comprising:
an analog frontend for the capacitive sensing, the analog frontend interfacing with a plurality of capacitive sensing electrodes to obtain a plurality of touch signals, wherein the analog frontend generates the sensing waveform.

12. The TDDI circuit of claim 11 , further comprising:
an image processing circuit configured to generate the processed image signal based on a received image signal obtained from a host application processor;
a touch processing circuit configured to generate a touch output signal by processing the plurality of touch signals.

13. The TDDI circuit of claim 11 , wherein determining the timing for the compensatory modulation comprises:
obtaining, the timing from the analog frontend.

14. The TDDI circuit of claim 10 , wherein the amplitude of the compensatory modulation is selected to, at least partially, compensate for an artifact on the data voltage at the pixel circuit, the artifact associated with the sensing waveform coupled onto the data voltage via a parasitic capacitance.

15. The TDDI circuit of claim 10 ,
wherein applying the compensatory modulation to the data voltage comprises:
additively superimposing the compensatory modulation on the data voltage.

16. The TDDI circuit of claim 10 ,
wherein the source driver is further configured to perform a gamma transformation to obtain the data voltage from a gray level specified by input image data, and
wherein performing the gamma transformation comprises applying the compensatory modulation as an amplitude increment to the data voltage.

17. A method for driving a display of an input-display device, the method comprising:
generating a data voltage for driving a pixel circuit of the display;
determining a timing for a compensatory modulation of the data voltage,
wherein the timing is determined using a sensing waveform of a capacitive sensing;

determining an amplitude of the compensatory modulation, wherein the amplitude of the compensatory modulation is based at least in part on measured capacitances and the sensing waveform, wherein different amplitudes of the compensatory modulation are used depending on the amplitude of the sensing waveform;
generating a modulated data voltage by applying the compensatory modulation to the data voltage; and
driving the pixel circuit using the modulated data voltage.

18. The method of claim 17 , wherein determining the timing for the compensatory modulation comprises:
obtaining, the timing from an analog frontend for proximity sensing, the analog frontend configured to generate the sensing waveform.

19. The method of claim 17 , wherein applying the compensatory modulation to the data voltage comprises:
additively superimposing the compensatory modulation on the data voltage.

20. The method if claim 17 , further comprising:
performing a gamma transformation to obtain the data voltage from a gray level specified by input image data, and
wherein performing the gamma transformation comprises applying the compensatory modulation as an increment to the data voltage.

Assignees

• Synaptics Inc

Inventors

• Ito Daisuke
• Losh Jonathan

Classifications

• G09G2310/027

  Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title

• G06F3/04166

  Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving (Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184) · CPC title

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title

• G06F3/044

  by capacitive means · CPC title