Electronic circuit having display driving function, touch sensing function and fingerprint sensing function

Patent metadata

Field	Value
Publication number	US-11270095-B2
Application number	US-202016921921-A
Country	US
Kind code	B2
Filing date	Jul 6, 2020
Priority date	Aug 21, 2019
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

An electronic circuit for driving a panel including touch sensors and fingerprint sensors is provided. The electronic circuit includes a touch sensing circuit, a fingerprint sensing circuit and a display driving circuit. The touch sensing circuit senses a touch of a finger and determines a first area corresponding to the touch on the panel. The fingerprint sensing circuit senses a fingerprint image of the finger corresponding to the first area of the panel. The display driving circuit drives pixels over the panel with respective first gray levels during a first phase, and drives pixels of the first area with respective second gray levels and pixels of a second area outside the first area with respective third gray levels during a second phase. The respective second gray levels are higher than the respective first gray levels, and the respective third gray levels are lower than the respective second gray levels.

First claim

What is claimed is:

1. An electronic circuit adapted to drive a display panel comprising touch sensors and fingerprint sensors, the electronic circuit comprising:
a touch sensing circuit, configured to sense a touch of a finger and determine a first area corresponding to the touch on the display panel;
a fingerprint sensing circuit, configured to sense a fingerprint image of the finger corresponding to the first area of the display panel; and
a display driving circuit, configured to drive pixels over the display panel with respective first gray levels during a first phase, and drive pixels of the first area with respective second gray levels and pixels of a second area outside the first area with respective third gray levels during a second phase, wherein the second phase comes later than the first phase,
wherein the respective second gray levels are higher than the respective first gray levels, and the respective third gray levels are lower than the respective second gray levels,
wherein the display driving circuit generates first gamma voltages corresponding to the respective second gray levels according to a first gamma curve, and the display driving circuit generates second gamma voltages corresponding to the respective third gray levels according to a second gamma curve,
wherein the first gamma curve and the second gamma curve are applied in a same mode.

2. The electronic circuit of claim 1 , wherein the respective third gray levels are substantially the same as the respective first gray levels.

3. The electronic circuit of claim 1 , further comprising:
a first interface circuit, wherein the touch sensing circuit, via the first interface circuit, controls the fingerprint sensing circuit to initiate a fingerprint scanning for the first area and sense the fingerprint image of the finger from the first area when the touch is recognized to be valid.

4. The electronic circuit of claim 3 , wherein the touch is recognized valid when a detected touch area is larger than a predetermined threshold area.

5. The electronic circuit of claim 3 , wherein
the fingerprint sensing circuit works in a power saving mode during the first phase, and
the touch sensing circuit, via the first interface circuit, wakes up the fingerprint sensing circuit from the power saving mode to a normal power mode during the second phase.

6. The electronic circuit of claim 1 , further comprising:
a second interface circuit, wherein the touch sensing circuit, via the second interface circuit, controls the display driving circuit to drive the pixels of the first area with the respective second gray levels and the pixels of the second area with the respective third gray levels during the second phase.

7. The electronic circuit of claim 6 , wherein the touch sensing circuit, via the second interface circuit, controls the display driving circuit to drive the pixels of the first area with a display pattern indicating a fingerprint input region.

8. The electronic circuit of claim 6 , wherein the touch sensing circuit, via the second interface circuit, controls the display driving circuit to adjust a backlight by a pulse width modulation (PWM) signal.

9. The electronic circuit of claim 8 , wherein the display driving circuit adjusts a brightness of the backlight by adjusting a duty ratio of the PWM signal.

10. The electronic circuit of claim 8 , wherein the display driving circuit adjusts the backlight by adjusting a frequency of the PWM signal.

11. The electronic circuit of claim 1 , wherein an absolute value of one of the first gamma voltages is larger than an absolute value of a corresponding one of the second gamma voltages for a specified pixel data.

12. The electronic circuit of claim 1 , wherein the display driving circuit generates third gamma voltages corresponding to the respective first gray levels according to the first gamma curve.

13. The electronic circuit of claim 1 , wherein a brightness of a backlight in the second phase is larger than that in the first phase.

14. The electronic circuit of claim 1 , wherein the fingerprint sensing circuit transmits the fingerprint image to an application processor for a fingerprint identification operation performed by the application processor.

15. The electronic circuit of claim 1 , wherein the first area is a local region of the display panel.

16. The electronic circuit of claim 1 , wherein the electronic circuit is implemented in a single semiconductor chip.

17. The electronic circuit of claim 1 , wherein the electronic circuit is implemented in at least two semiconductor chips comprising a first semiconductor chip and a second semiconductor chip, wherein the first semiconductor chip comprises the touch sensing circuit and the display driving circuit, and the second semiconductor chip comprises the fingerprint sensing circuit.

18. An electronic circuit adapted to drive a display panel comprising touch sensors and fingerprint sensors, the electronic circuit comprising:
a touch sensing circuit, configured to sense a touch of a finger and determine a first area corresponding to the touch on the display panel;
a fingerprint sensing circuit, configured to sense a fingerprint image of the finger corresponding to the first area of the display panel; and
a display driving circuit, configured to drive pixels over the display panel with respective first gray levels during a first phase, and drive pixels of the first area with respective second gray levels and pixels of a second area outside the first area with respective third gray levels during a second phase, wherein the second phase comes later than the first phase,
wherein the respective second gray levels are higher than the respective first gray levels, and the respective third gray levels are lower than the respective second gray levels,
wherein the display driving circuit generates the respective third gray levels for the second area during the second phase by modifying respective fourth gray levels according to a data processing curve, and the display driving circuit generates gamma voltages corresponding to the respective second gray levels and the respective third gray levels according to the same gamma curve.

19. An electronic circuit adapted to drive a display panel comprising touch sensors and fingerprint sensors, wherein the electronic circuit co-operates with the display panel and an application processor for a fingerprint identification operation, the electronic circuit comprising:
a touch sensing circuit, configured to sense a touch of a finger and determine a first area corresponding to the touch on the display panel;
a display driving circuit, configured to drive pixels of the first area of the display panel with a display pattern indicating a fingerprint input region;
a fingerprint sensing circuit, configured to sense a fingerprint image of the finger corresponding to the first area of the display panel;
a first interface circuit, wherein the touch sensing circuit, via the first interface circuit, controls the fingerprint sensing circuit to initiate a fingerprint scanning for the first area and sense the fingerprint image of the finger from the first area when the touch is recognized to be valid,
wherein the fingerprint sensing circuit transmits the fingerprint image to the application processor for the fingerprint identification operation performed by the application processor; and
a second interface circuit, wherein the touch sensing circuit, via the second interface circuit, controls the display driving circuit to drive the pixels of the first

Assignees

• Novatek Microelectronics Corp

Inventors

• Shih Wei-Lun
• Hsieh Tzu-Wen
• Cheng Huan-Teng
• Tang Huang-Chin
• Mai Yueh-Teng
• Huang Shi-Hao
• Lee Jung-Chung

Classifications

• G09G3/20

  for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} · CPC title

• G09G2320/0626

  for control of overall brightness · CPC title

• G06V40/1318 Primary

  using electro-optical elements or layers, e.g. electroluminescent sensing · CPC title

• G09G2320/0653

  Controlling or limiting the speed of brightness adjustment of the illumination source · CPC title

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title