Pixel circuit and control method

Abstract

One aspect of this disclosure provides a control method for enabling a pixel circuit to perform photosensing. The control method includes controlling a drive circuit of the pixel circuit to prevent the light-emitting diode (LED) of the pixel circuit from emitting light. The control method also includes controlling a first thin-film transistor of a readout circuit of the pixel circuit to conduct, enabling the LED to perform photosensing and outputting a first photosensing signal. The control method also includes controlling the drive circuit to enable the LED to emit light. The control method also includes controlling the first thin-film transistor to de-conduct, enabling the first thin-film transistor to perform photosensing and outputting a second photosensing signal.

Claims

1. A pixel circuit, comprising: One driving circuit; A readout circuit includes a first thin-film transistor, a first terminal of which is coupled to the driving circuit. A light-emitting diode (LED) has a first terminal coupled to the first terminal of the first thin-film transistor of the driving circuit and the reading circuit; a control circuit is coupled to a control terminal of the first thin-film transistor of the driving circuit and the reading circuit, wherein when the pixel circuit performs photosensing, the control circuit controls the driving circuit to prevent the LED from emitting light, so that the LED performs photosensing, and controls the first thin-film transistor of the reading circuit to conduct to output a first photosensitizing signal; or the control circuit controls the driving circuit to make the LED emit light, and controls the first thin-film transistor of the reading circuit to deconduct, so that the first thin-film transistor performs photosensing to output a second photosensitizing signal.

2. The pixel circuit as claimed in claim 1, wherein the driving circuit comprises: The first transistor; A second transistor, a control terminal of which is coupled to a first terminal of the first transistor, and a first terminal of the second transistor is coupled to a first power supply; a third transistor, a first terminal of which is coupled to a second terminal of the second transistor, a second terminal of which is coupled to the first terminal of the light-emitting diode, and a control terminal of which is coupled to the control circuit, wherein a second terminal of the light-emitting diode is coupled to a second power supply, wherein the control circuit controls the driving circuit to make the light-emitting diode light up or not light up by controlling the conduction or non-conduction of the third transistor.

3. The pixel circuit as described in claim 1, wherein, During a frame of the pixel circuit, the first period during which the control circuit controls the light-emitting diode to perform photosensing and the second period during which the first thin-film transistor performs photosensing each account for 50%.

4. The pixel circuit as described in claim 1, wherein, During a frame of the pixel circuit, the first period during which the control circuit controls the light-emitting diode to perform light sensing accounts for less than 50%, while the second period during which the first thin-film transistor performs light sensing accounts for more than 50%.

5. The pixel circuit as described in claim 1, wherein, During a frame of the pixel circuit, a first period in which the control circuit controls the light-emitting diode to perform light sensing accounts for more than 50%, while a second period in which the first thin-film transistor performs light sensing accounts for less than 50%.

6. The pixel circuit as described in claim 1, wherein, During a frame of the pixel circuit, the control circuit controls the light-emitting diode to perform a first period of light sensing and the first thin-film transistor to perform light sensing in a plurality of alternating complementary switching.

7. The pixel circuit of claim 1, wherein the readout circuit further includes a second thin-film transistor, a first terminal of the second thin-film transistor being coupled to a second terminal of the first thin-film transistor, and a control terminal of the second thin-film transistor being coupled to the control circuit.

8. The pixel circuit as described in claim 7, wherein, When the pixel circuit performs photosensing, the control circuit controls the driving circuit to de-emphasize the light-emitting diode, enabling the light-emitting diode to perform photosensing, and controls the first and second thin-film transistors of the readout circuit to conduct to output the first photosensitizing signal; or the control circuit controls the driving circuit to de-emphasize the light-emitting diode, de-conduct the first thin-film transistor of the readout circuit, and conduct the second thin-film transistor, enabling the first thin-film transistor to perform photosensing and output the second photosensitizing signal; or the control circuit... The circuit controls the driving circuit to prevent the light-emitting diode from emitting light, controls the first thin-film transistor of the reading circuit to be turned on, and controls the second thin-film transistor to be turned off, so that the second thin-film transistor performs photosensing and outputs a third photosensing signal; or the control circuit controls the driving circuit to prevent the light-emitting diode from emitting light, controls the first thin-film transistor of the reading circuit to be turned off, and controls the second thin-film transistor to be turned off, so that the first thin-film transistor and the second thin-film transistor perform photosensing simultaneously and output a fourth photosensing signal.

9. A control method for enabling a pixel circuit to perform light sensing, comprising: A driving circuit controls the pixel circuit to prevent a light-emitting diode of the pixel circuit from emitting light; a first thin-film transistor of a reading circuit of the pixel circuit is turned on to enable the light-emitting diode to perform photosensing and output a first photosensing signal; the driving circuit is controlled to enable the light-emitting diode to emit light; and the first thin-film transistor is controlled to be turned off to enable the first thin-film transistor to perform photosensing and output a second photosensing signal.

10. The control method as described in claim 9, wherein, During one frame of the pixel circuit, the first period for controlling the light-emitting diode to perform photosensing and the second period for controlling the first thin-film transistor to perform photosensing each account for 50%.

11. The control method as described in claim 9, wherein, During a frame of the pixel circuit, a first period in which the light-emitting diode is controlled to perform light sensing accounts for less than 50%, while a second period in which the first thin-film transistor is controlled to perform light sensing accounts for more than 50%.

12. The control method as described in claim 9, wherein, During a frame of the pixel circuit, a first period in which the light-emitting diode is controlled to perform light sensing accounts for more than 50%, while a second period in which the first thin-film transistor is controlled to perform light sensing accounts for less than 50%.

13. The control method as described in claim 9, wherein, During a frame of the pixel circuit, a first period for controlling the light-emitting diode to perform light sensing and a second period for controlling the first thin-film transistor to perform light sensing are alternately and complementaryly switched multiple times.

14. The control method as claimed in claim 9, wherein the read circuit further includes a second thin-film transistor coupled to the first thin-film transistor.

15. The control method as described in claim 14, wherein the control method further comprises: The driving circuit is controlled to prevent the light-emitting diode from emitting light, so that the light-emitting diode can perform light sensing. And control the first thin-film transistor and the second thin-film transistor to conduct so as to output the first photosensitive signal.

16. The control method as described in claim 14, wherein the control method further comprises: The driving circuit is controlled to prevent the light-emitting diode from emitting light. The first thin-film transistor controlling the read circuit is not conducting; And control the second thin-film transistor to conduct so that the first thin-film transistor performs photosensing and outputs the second photosensitized signal.

17. The control method as described in claim 14, wherein the control method further comprises: The driving circuit is controlled to prevent the light-emitting diode from emitting light. The first thin-film transistor controlling the readout circuit is turned on; And control the second thin-film transistor to be de-conductive, so that the second thin-film transistor performs photosensing and outputs a third photosensitizing signal.

18. The control method as described in claim 14, wherein the control method further comprises: The driving circuit is controlled to prevent the light-emitting diode from emitting light. The first thin-film transistor controlling the read circuit is not conducting; And control the second thin-film transistor to be de-conductive, so that the first thin-film transistor and the second thin-film transistor can simultaneously perform photosensing to output a fourth photosensitizing signal.

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