Method of sensing characteristic value of circuit element and display device using it

Patent metadata

Field	Value
Publication number	US-10818240-B2
Application number	US-201916689905-A
Country	US
Kind code	B2
Filing date	Nov 20, 2019
Priority date	Nov 20, 2018
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A present disclosure relates to a method of sensing characteristic value of circuit element and display using it. The display device is able to accurately sense deterioration of the organic light-emitting diode disposed in each subpixel of a display panel and compensate for the deterioration. The method of sensing characteristic value of circuit element is able to save a sensing time for an entire display panel and improve a driving speed of the display device by efficiently performing a deterioration sensing process of the organic light-emitting diode.

First claim

The invention claimed is:

1. A display device, comprising:
a display panel including a plurality of gate lines, a plurality of data lines, and a plurality of subpixels formed adjacent to overlapping locations of the gate lines and the data lines;
a gate driver circuit for driving the plurality of gate lines;
a data driver circuit for driving the plurality of data lines;
a deterioration sensing circuit electrically connected to the plurality of the subpixels for sensing deterioration of a first organic light-emitting diode in a first subpixel of the plurality of subpixels and a second organic light-emitting diode in a second subpixel of the plurality of subpixels, wherein the first organic light-emitting diode is connected to a first gate line of the plurality of gate lines and the second organic light-emitting diode is connected to a second gate line of the plurality of gate lines; and
a timing controller for controlling signals applied to the gate driver circuit and the data driver circuit,
wherein the timing controller controls the gate driver circuit to progress a first deterioration sensing process including an initializing period, a boosting period, and a sampling period with respect to the first organic light-emitting diode in the first subpixel connected to the first gate line, and to begin another initializing period of a second deterioration sensing process during the boosting period of the first deterioration sensing process with respect to the second organic light-emitting diode in the second subpixel connected to a second gate line.

2. The display device according to claim 1 , wherein the subpixel of the plurality of subpixels comprises:
an organic light-emitting diode;
a driving transistor driving the organic light-emitting diode and receiving a driving voltage-for-sensing deterioration, the driving transistor including a source node, a gate node, and a drain node;
a switching transistor electrically connected between the gate node of the driving transistor and a data line among the plurality of data lines; and
a sensing transistor electrically connected between either the source node or the drain node of the driving transistor and a reference voltage line.

3. The display device according to claim 1 , wherein the deterioration sensing circuit comprises:
an amplifier in which a non-inverting input terminal receives a reference voltage-for-sensing and an inverting input terminal is connected to a reference voltage line;
a feedback capacitor electrically connected between the inverting input terminal and an output terminal of the amplifier;
a reset switch connected to the feedback capacitor in parallel; and
a sampling switch connected to the output terminal of the amplifier.

4. The display device according to claim 1 , wherein the deterioration sensing process with respect to the first organic light-emitting diode comprises:
an initializing period in which a high level scan signal is supplied to the first gate line to charge a voltage for the deterioration sensing the first organic light-emitting diode;
a boosting period in which a parasitic capacitor of the first organic light-emitting diode is charged by a current flowing through the first organic light-emitting diode after the voltage charging for the deterioration sensing of the first organic light-emitting diode is completed; and
a sampling period in which a capacitance charged in the parasitic capacitor of the first organic light-emitting diode is detected.

5. The display device according to claim 4 , wherein the deterioration sensing process with respect to the first organic light-emitting diode further comprises a reset period for resetting the deterioration sensing circuit after the sampling period.

6. The display device according to claim 5 , wherein a time interval between the first deterioration sensing process and the second deterioration sensing process is larger than a time duration of the reset period of the deterioration sensing circuit.

7. A method of sensing a characteristic value of a circuit element in a display device comprising:
charging a voltage of a first organic light-emitting diode connected to a first gate line at a first initializing period;
charging a parasitic capacitor connected parallel to the first organic light-emitting diode at a first boosting period, wherein the first boosting period starts after the first initializing period;
detecting a parasitic capacitance of the parasitic capacitor at a first sampling period after the first boosting period; and
charging a voltage of a second organic light-emitting diode connected to a second gate line at a second initializing period during the first boosting period of the first organic light-emitting diode.

8. The method according to claim 7 , further comprising:
forming a subpixel, wherein forming the subpixel includes:
forming an organic light-emitting diode;
forming a driving transistor driving the organic light-emitting diode that is configured to receive a driving voltage-for-sensing deterioration;
forming a switching transistor electrically connected between a gate node of the driving transistor and a data line among a plurality of data lines; and
forming a sensing transistor electrically connected between a source node or a drain node of the driving transistor and a reference voltage line.

9. The method according to claim 8 , further comprising:
forming a deterioration sensing circuit, wherein forming the deterioration sensing circuit includes:
forming an amplifier in which a non-inverting input terminal receives a reference voltage-for-sensing and an inverting input terminal is connected to a reference voltage line;
forming a feedback capacitor electrically connected between the inverting input terminal and an output terminal of the amplifier;
forming a reset switch connected to the feedback capacitor in parallel; and
forming a sampling switch connected to the output terminal of the amplifier.

10. The method according to claim 9 , further comprising:
resetting the deterioration sensing circuit after the sampling period during a reset period.

11. The method according to claim 10 , wherein a time interval between the first initializing period and the second initializing period is larger than a time duration of the reset period of the deterioration sensing circuit.

12. The method according to claim 7 , wherein charging a voltage of a first organic light-emitting diode connected to a first gate line at a first initializing period includes:
supplying a high level scan signal to the first gate line to charge a voltage for the first organic light-emitting diode.

13. The method according to claim 7 , wherein charging a parasitic capacitor connected parallel to the first organic light-emitting diode at a first boosting period includes:
charging the parasitic capacitor of the first organic light-emitting diode by a current flowing through the first organic light-emitting diode after the voltage charging for the first organic light-emitting diode is completed.

14. The method according to claim 7 , wherein detecting a parasitic capacitance of the parasitic capacitor at a first sampling period after the first boosting period includes:
detecting the parasitic capacitance charged in the parasitic capacitor of the first organic light-emitting diode.

Assignees

• Lg Display Co Ltd

Inventors

• Park Kwangmo

Classifications

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title

• G09G3/3266 Primary

  Details of drivers for scan electrodes · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title