KR101731120B1 - Organic Light Emitting Diode Display And Driving Method Thereof - Google Patents

Abstract

A method of driving an organic light emitting diode display according to the present invention includes compensating a deterioration of an organic light emitting diode; Comparing the first panel current flowing in the display panel after compensating for the deterioration with a second panel current flowing in the display panel before compensating for the deterioration, thereby obtaining a panel current increment; And lowering the overall luminance of the display panel based on the panel current increment.

Description

[0001] The present invention relates to an organic light emitting diode (OLED) display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode display device and a driving method thereof, which are related to deterioration compensation of an organic light emitting diode.

2. Description of the Related Art In recent years, an organic light emitting diode display device that has been spotlighted as a display device has advantages of high response speed, high luminous efficiency, high brightness, and a wide viewing angle by using a self-luminous element that emits light by itself.

The organic light emitting diode display device has an organic light emitting diode (OLED) that emits self-light as shown in FIG. The OLED has organic compound layers (HIL, HTL, EML, ETL, EIL) formed between the anode electrode and the cathode electrode.

The organic compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer EIL). When a driving voltage is applied to the anode electrode and the cathode electrode, holes passing through the HTL and electrons passing through the ETL are transferred to the EML to form excitons, Thereby generating visible light.

The organic light emitting diode display device arranges the pixels including the OLED in a matrix form and controls the brightness of the pixels selected by the gate pulse according to the gradation of the video data.

The non-uniformity of the luminance between the pixels in the organic light emitting diode display device is caused by various causes, for example, electric characteristic deviation of the driving TFT, deviation of the high-potential driving voltage according to the display position, and deterioration of the OLED. Particularly, the deterioration of the OLED occurs because the deterioration rate of the OLED varies depending on the pixels for a long period of time. When this deteriorates, an image sticking phenomenon occurs, resulting in deterioration of image quality.

Various degradation compensation methods have been proposed to compensate for the deterioration of the OLED. The deterioration compensation method detects the deterioration degree of the pixel through a compensation circuit or an external compensation circuit in the pixel and increases the luminance of the pixel in consideration of the detected deterioration degree to realize the original intended luminance. When the pixel deteriorates, the efficiency of light emission of the OLED is lowered, so that the degraded pixel has luminance lower than the target luminance with respect to the same power supply amount. Accordingly, compensating for the deterioration means that the driving power applied to the deteriorated pixel is increased as shown in FIG. 2, thereby realizing the desired luminance in the deteriorated pixel.

In this deterioration compensation, since the power supply amount increases as the degree of deterioration of the pixels increases, deterioration compensation is a serious disadvantage for a mobile application product in which power consumption is very important.

Also, as shown in FIG. 3, as the deterioration progresses, the driving current applied to the pixel increases to realize the target luminance, so that the deterioration acceleration phenomenon that increases the deterioration occurs. The organic light emitting diode display device that performs deterioration compensation on the average has a shorter lifetime characteristic than the organic light emitting diode display device that does not compensate for deterioration, and has a large power consumption and over current risk.

Accordingly, it is an object of the present invention to provide an organic light emitting diode display device and a driving method thereof, which can mitigate the phenomenon of accelerated deterioration due to deterioration compensation, and reduce power consumption and overcurrent risk.

According to an aspect of the present invention, there is provided a method of driving an organic light emitting diode display, including: compensating for deterioration of an organic light emitting diode; Comparing the first panel current flowing in the display panel after compensating for the deterioration with a second panel current flowing in the display panel before compensating for the deterioration, thereby obtaining a panel current increment; And lowering the overall luminance of the display panel based on the panel current increment.

In the step of lowering the total luminance of the display panel, the driving current applied to each pixel is lowered by a value obtained by dividing the panel current increment by the total number of pixels of the display panel.

Wherein the step of lowering the total luminance of the display panel reads the luminance adjustment value from the look-up table using the panel current increment as a read address, and based on the luminance adjustment value, .

Wherein the step of lowering the total luminance of the display panel reads the luminance adjustment value from the lookup table using the panel current increment as a read address and adjusts a reference voltage applied to the pixels of the display panel based on the luminance adjustment value do.

Wherein the step of lowering the total luminance of the display panel reads the luminance adjustment value from the lookup table using the panel current increment as a read address and determines a scan pulse applied to the pixels of the display panel based on the luminance adjustment value, The time required for the light emission period during one frame period is reduced.

Wherein the step of lowering the total luminance of the display panel reads the luminance adjustment value from the lookup table using the panel current increment as a read address and downsizes the video data to be applied to the pixels of the display panel based on the luminance adjustment value Modulate.

An OLED display according to an exemplary embodiment of the present invention includes a display panel having a plurality of pixels each having an organic light emitting diode; A deterioration compensation circuit for compensating deterioration of the organic light emitting diode; And comparing the first panel current flowing in the display panel after compensating for the deterioration with a second panel current flowing in the display panel before compensating for the deterioration to obtain a panel current increment, And a luminance control circuit for lowering the total luminance of the display panel.

The organic light emitting diode display device and the driving method thereof according to the present invention can lower the total luminance of the display panel by an amount corresponding to the increase of the panel current by the deterioration compensation so that the power consumption increased by the deterioration compensation can be reduced to the level before the deterioration compensation. Accordingly, the present invention can alleviate the phenomenon of acceleration of deterioration due to the deterioration compensation, and further reduce the power consumption and the risk of the overcurrent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an emission principle of an OLED; FIG.
Fig. 2 is a view showing a power supply amount applied to a pixel before and after deterioration compensation; Fig.
FIG. 3 is a view showing that deterioration of a pixel is accelerated rather by a conventional deterioration compensation method. FIG.
4 is a view illustrating a driving method of an organic light emitting diode display according to an embodiment of the present invention.
5 illustrates a portion of OLED degradation compensation;
6A to 6D show examples of lowering the total luminance of the display panel by a panel current increment.
7 is a diagram showing an example of adjustment of a scan pulse and an emission pulse.
8 is a view showing a comparison between the power consumption after deterioration compensation and the power consumption after luminance control.
9 is a schematic view illustrating an organic light emitting diode display device according to an embodiment of the present invention.
10 is a view showing an equivalent circuit of the pixel shown in Fig.
11 is a view showing driving waveforms of a scan pulse, a sensing pulse and an emission pulse for driving a pixel.
Figs. 12-15 illustrate various embodiments of a luminance control circuit. Fig.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 4 to 15. FIG.

4 to 7 illustrate a method of driving an organic light emitting diode display according to an embodiment of the present invention.

Referring to FIG. 4, the driving method according to the present invention performs OLED deterioration compensation. (S10) OLED deterioration compensation is performed by using the OLED threshold voltage Vth_OLED) is compared with the initial OLED threshold voltage before deterioration to calculate the threshold voltage shift amount DELTA Vth and a luminance reduction amount DELTA L corresponding to the threshold voltage shift amount DELTA Vth is derived using a lookup table or the like. Then, the modulation data is generated by adding the compensation value for compensating the luminance reduction amount? L to the input video data, and then the modulated data is applied to the pixel P.

After the OLED deterioration compensation, the driving method according to the present invention detects the panel current flowing in the display panel using a current sensor or the like and stores the detected panel current in a RAM (Random Access Memory). (S20) (Stored in the ROM (Read Only Memory) immediately after the drive power supply is applied) flowing in the display panel (S30)

The driving method according to the present invention determines whether the panel current is increased after OLED deterioration compensation compared with before OLED deterioration compensation (S40)

In the driving method according to the present invention, if it is determined in step S40 that the panel current is increased (Yes in step S40), the overall brightness of the display panel is decreased based on the panel current increase. (S50) The driving current applied to each pixel can be lowered by a value obtained by dividing the panel current increment by the total number of pixels of the display panel. The pixels whose driving current is low include not only deteriorated pixels which cause the panel current increase but also pixels which are not deteriorated.

For example, assuming that one pixel out of all 100 pixels is degraded and the deterioration of the pixel is compensated (the driving current is further increased so as to exhibit the original luminance) and the increment of the panel current is earlier than before the compensation, The driving current applied to each of the 100 pixels is decreased by 0.01 A by the panel current increment of the panel current. As a result, driving currents smaller by 0.01 A than the original driving current are applied to the 99 pixels which are not deteriorated, and driving currents larger by 0.99 A than the original driving current are supplied to one deteriorated pixel A driving current smaller than the current value 1A by 0.01 A) is applied. This has the advantage that the increase of the panel current due to deterioration compensation can be effectively suppressed. Of course, although the total luminance of the display panel is slightly lowered, since the amount of luminance drop is distributed to all the pixels, the luminance lifetime according to the present invention does not violate the normal luminance lifetime specification required by the display device.

Meanwhile, the driving method according to the present invention may reduce the total luminance of the display panel to be smaller or larger than the panel current increase by adjusting the stored value of the lookup table. In the following description, however, the overall luminance of the display panel is reduced by the amount of the panel current increase. The method of lowering the total luminance of the display panel by the panel current increment can be implemented by various methods as shown in Figs. 6A to 6D.

As a first example, the driving method according to the present invention compares the panel current (panel current after deterioration compensation) detected by the current sensor with the initial panel current (panel current before deterioration compensation) as shown in FIG. 6A, +)? Ipanel). The luminance adjustment value is read out from the look-up table with the panel current increment ((+) Ipanel) as the read address. Based on this luminance adjustment value, the high potential driving voltage Vdd_EL) to reduce the panel current Ipanel flowing in the display panel by the panel current increment ((+) Ipanel).

As a second example, the driving method according to the present invention compares the panel current (panel current after deterioration compensation) detected by the current sensor with the initial panel current (panel current before deterioration compensation) as shown in FIG. 6B, +)? Ipanel). Then, the luminance adjustment value is read from the lookup table using the panel current increment ((+) Ipanel) as the read address, and the reference voltage Vref applied to the pixels P as shown in FIG. 10, Thereby decreasing the panel current Ipanel flowing in the display panel by the panel current increment ((+) Ipanel). The current flowing in the OLED in the pixel P shown in FIG. 10 is proportional to the square of the data voltage minus the reference voltage Vref, so that the panel current Ipanel decreases as the reference voltage Vref increases.

As a third example, the driving method according to the present invention compares the panel current (panel current after deterioration compensation) detected by the current sensor with the initial panel current (panel current before deterioration compensation) as shown in FIG. +)? Ipanel). Then, the luminance adjustment value is read out from the look-up table using the panel current increment ((+) Ipanel) as the read address. Based on the luminance adjustment value, the scan pulse SCAN applied to the pixels P, And the emission pulse EM as shown in FIG. 7, thereby reducing the panel current Ipanel flowing in the display panel by the panel current increment ((+) Ipanel).

In FIG. 7, 'T1' indicates a programming period for determining the gate-source voltage of the driving TFT DT included in the pixel P shown in FIG. 10, 'T2' indicates a light emission Indicate the period. The programming operation is performed in the pixel P by the scan pulse SCAN held at the turn-on level in the programming period T1 and the emission pulse EM is maintained at the turn-off level in this period T1 Thereby blocking current conduction to the OLED. In the light emission period T2, the scan pulse SCAN is maintained at the turn-off level, and the emission pulse EM is maintained at the turn-on level so that current flows in the OLED. If the programming period T1 is increased and the light emission period T2 is decreased based on the luminance adjustment value within one frame period 1F, the time for which the OLED is turned on is shortened and the panel current Ipanel is reduced.

As a fourth example, the driving method according to the present invention compares the panel current (panel current after deterioration compensation) detected by the current sensor with the initial panel current (panel current before deterioration compensation) as shown in FIG. 6D, +)? Ipanel). By reading the luminance adjustment value from the lookup table using the panel current increment ((+) Ipanel) as the read address and lowering the video data to be applied to the pixels P as shown in FIG. 10 based on the luminance adjustment value (Ipanel) flowing in the display panel by the panel current increment ((+) Ipanel).

The driving method according to the present invention drives the display panel in a state where the total luminance of the display panel is lowered. (S60) In the driving method according to the present invention, if it is determined in S40 that the panel current is not increased , The display panel is driven without adjusting the overall luminance of the display panel. (S60)

Fig. 8 shows a comparison between the power consumption after degradation compensation and the power consumption after luminance control.

8, the driving method according to the present invention effectively suppresses the increase of the panel current due to the deterioration compensation, thereby reducing the power consumption ((X +?) MW) increased by the deterioration compensation to the level ) mW). As a result, the driving method according to the present invention can mitigate the deterioration acceleration phenomenon due to the deterioration compensation, and can further reduce the power consumption and the risk of the overcurrent.

9 to 11 show an organic light emitting diode display device according to an embodiment of the present invention.

9, an OLED display according to an exemplary embodiment of the present invention includes a display panel 10, a data driving circuit 12 for driving the data lines 14, gate lines 15, A timing controller 11 for controlling the operation timings of the data driving circuit 12 and the gate driving circuit 13 and a power supply circuit 16. The timing controller 11 controls the operation timing of the data driving circuit 12 and the gate driving circuit 13,

In the display panel 10, a plurality of data lines 14 and a plurality of gate lines 15 cross each other, and the pixels P are arranged in a matrix form for each of the intersection regions. Each of the gate lines 15 includes a scan line 15a for supplying a scan pulse, an emission line 15b for supplying an emission pulse, and a sensing line 15c for supplying a sensing pulse. Each pixel P is connected to the data driving circuit 12 through the data line 14 and to the gate driving circuit 13 through the gate line 15. [ Each pixel P includes an organic light emitting diode, a driving TFT, a plurality of switch TFTs, and a storage capacitor. The configuration of the pixel P can be variously changed depending on the compensation scheme.

The timing controller 11 is based on timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock signal DCLK, and a data enable signal DE input from a system board (not shown) A data control signal DDC for controlling the operation timing of the data driving circuit 12 and a gate control signal GDC for controlling the operation timing of the gate driving circuit 13. [

The timing controller 11 compares the OLED threshold voltage sensed in the pixel P with the first OLED threshold voltage before deterioration to compute the threshold voltage shift amount and compares the threshold voltage shift amount Lt; RTI ID = 0.0 > a < / RTI > Then, the modulation data is generated by adding the compensation value for compensating the luminance reduction amount to the input video data, and then the modulation data is supplied to the data driving circuit 12. [

The data driving circuit 12 converts the modulated data into analog data voltages under the control of the timing controller 11 and supplies them to the data lines 14. [ The data driving circuit 12 applies a sensing voltage to the pixels P and sequentially samples the OLED threshold voltages sensed by the pixels P and supplies the sensing voltage to the timing controller 11 Supply. The components of the data drive circuit 12 for degradation compensation are described in detail in Application No. 10-2009-0113979, filed by the present applicant. The deterioration compensating circuit described in the claims of the present invention includes, in addition to the data driving circuit 12, a part of the timing controller, a pixel circuit, and the like.

The gate drive circuit 13 generates a scan pulse SCAN, a sensing pulse SEN and an emission pulse EM under the control of the timing controller 11. [ Then, the scan pulse SCAN is applied to the scan lines 15a in a line-sequential manner, the emission pulse EM is applied to the emission lines 15b in a line-sequential manner, and the sensing pulse SEN is applied To the sensing lines 15c in a line sequential manner. The shift register array constituting the gate drive circuit 13 can be formed directly on the display panel 10 by a GIP (Gate In Panel) method.

The power supply circuit 16 generates and applies a high potential driving voltage Vdd_EL, a low potential driving voltage Vss and a reference voltage Vref to the pixels P of the display panel 10. The pixels P are commonly supplied with these voltages Vdd_EL, Vss, and Vref.

FIG. 10 shows an example of the pixel P shown in FIG. 11 shows driving waveforms of a scan pulse SCAN, a sensing pulse SEN and an emission pulse EM for driving the pixel P. In FIG.

10, the pixel P includes an OLED, a driving TFT DT, a plurality of switch TFTs ST1 to ST5, and a storage capacitor Cst. The driving TFT DT and the switch TFTs ST1 to ST5 may be implemented as a P-type MOSFET.

The OLED is connected between the third node N3 and the input terminal of the low potential voltage Vss and emits light by a current flowing between the input terminal of the high potential voltage Vdd_EL and the input terminal of the low potential voltage Vss.

The driving TFT DT is connected between the input terminal of the high potential voltage Vdd_EL and the third node N3 and is connected between the input terminal of the source node and the gate of the high potential voltage Vdd_EL, The amount of current flowing through the OLED is controlled according to the voltage applied between the OLEDs.

The first switch TFT ST1 is connected between the first node N1 and the drive TFT DT and is switched in response to a scan pulse SCAN from the scan line 15a. The second switch TFT ST2 is connected between the data line 14 and the second node N2 and is switched in response to the scan pulse SCAN from the scan line 15a. The third switch TFT ST3 is connected between the input terminal of the reference voltage Vref and the second node N2 and is switched in response to the emission pulse EM from the emission line 15b. The fourth switch TFT (ST4) is connected between the driver TFT (DT) and the third node (N3) and is switched in response to the emission pulse EM from the emission line (15b). The fifth switch TFT ST5 is connected between the data line 14 and the third node N3 and is switched in response to the sensing pulse SEN from the sensing line 15c.

The storage capacitor Cst is connected between the first node N1 and the second node N2.

Referring to FIG. 11, the operation of the pixel P in the state where the deterioration compensation is performed will be described below. The sensing pulse SEN is maintained at the turn-on level during some intervals for the deterioration compensation. However, when the deterioration compensation is completed, the sensing pulse SEN is always maintained at the turn-off level as shown in FIG. 11, so that the fifth switch TFT ST5 is continuously turned off . The pixel P operation in the deterioration compensation process is clearly described in the above-referenced patent.

During the programming period T1, the scan pulse SCAN is generated at the turn-on level L to turn on the first and second switch TFTs ST1 and ST2 of the pixel P, and the emission pulse EM Off level (H) to turn off the third and fourth switch TFTs (ST3, ST4) of the pixel (P). As a result, the data voltage Vdata reflecting the OLED deterioration compensation is applied to the second node N2 of the pixel P. [ In the pixel P, the intermediate compensation value is applied to the first node N1 by the diode connection of the drive TFT DT (the gate electrode and the drain electrode of the drive TFT DT are short-circuited). The intermediate compensation value is determined by subtracting the threshold voltage of the driving TFT DT from the high-potential driving voltage Vdd_EL. The storage capacitor Cst maintains the potential of the first node N1 at the intermediate compensation value and the potential at the second node N2 at the data voltage Vdata.

During the light emission period T2, the scan pulse SCAN is inverted to the turn-off level H to turn off the first and second switch TFTs ST1 and ST2 of the pixel P, On level L so that the third and fourth switch TFTs ST3 and ST4 of the pixel P are turned on. As a result, the reference voltage Vref is applied to the second node N2 of the pixel P and the potential of the second node N2 changes from the data voltage Vdata to the reference voltage Vref. Since the first node N1 is connected to the second node N2 with the storage capacitor Cst interposed therebetween, the potential change amount Vdata-Vref of the second node is maintained at the first node N1 ). Accordingly, the potential of the first node N1 is changed to the final compensation value obtained by subtracting the potential change amount (Vdata-Vref) of the second node from the intermediate compensation value. The final compensation value is for compensating the threshold voltage deterioration of the driving TFT DT.

At this time, the current flowing in the OLED is proportional to the square of (Vdata-Vref) ² obtained by subtracting the reference voltage Vref from the data voltage Vdata. That is, the current flowing through the OLED is independent of the threshold voltage of the driving TFT DT.

In such an organic light emitting diode display device, the panel current increases due to the OLED deterioration compensation during the pixel driving as described above. Therefore, the organic light emitting diode display device according to the present invention requires a luminance control circuit to lower the overall luminance of the display panel based on the panel current increase. The luminance control circuit can lower the driving current applied to each pixel by a value obtained by dividing the panel current increment by the total number of pixels of the display panel in order to lower the overall luminance of the display panel. The pixels whose driving current is low include not only deteriorated pixels which cause the panel current increase but also pixels which are not deteriorated. Meanwhile, the luminance control circuit according to the present invention may reduce the total luminance of the display panel to be smaller or larger than the panel current increase by adjusting the stored value of the lookup table. In the following description, however, the overall luminance of the display panel is reduced by the amount of the panel current increase. Hereinafter, various embodiments of the luminance control circuit will be described.

12 shows a first embodiment of the luminance control circuit.

Referring to Fig. 12, the luminance control circuit according to the first embodiment includes a power supply circuit 16, a current sensor 21, and a first look-up table 22.

The current sensor 21 detects the panel current flowing through the display panel 10 by sensing the power wiring that supplies the high potential driving voltage Vdd_EL to the pixels of the display panel 10 in common.

The power supply circuit 16 applies the high potential driving voltage Vdd_EL to the power wiring. The power supply circuit 16 receives the panel current (panel current after deterioration compensation) detected from the current sensor 21 and receives the panel current after deterioration (panel current after deterioration compensation) and the pre-stored initial panel current Panel current) to calculate the panel current increment. By reading the luminance adjustment value from the first look-up table 22 using the panel current increment as a read address and lowering the high potential drive voltage Vdd_EL applied to the pixels based on the luminance adjustment value, The panel current flowing through the display panel 10 is reduced.

13 shows a second embodiment of the luminance control circuit.

13, the luminance control circuit according to the second embodiment includes a power supply circuit 16, a current sensor 21, and a first look-up table 22. As shown in Fig.

The current sensor 21 detects the panel current flowing through the display panel 10 by sensing the power wiring that supplies the high potential driving voltage Vdd_EL to the pixels of the display panel 10 in common.

The power supply circuit 16 applies the high potential driving voltage Vdd_EL to the power wiring. The power supply circuit 16 receives the panel current (panel current after deterioration compensation) detected from the current sensor 21 and receives the panel current after deterioration (panel current after deterioration compensation) and the pre-stored initial panel current Panel current) to calculate the panel current increment. By reading the luminance adjustment value from the first lookup table 22 with the panel current increment as a read address and increasing the reference voltage Vref applied to the pixels based on the luminance adjustment value, Thereby reducing the panel current (Ipanel) flowing in the panel.

14 shows a third embodiment of the luminance control circuit.

14, the luminance control circuit according to the third embodiment includes a timing controller 11, a gate driving circuit 13, a power supply circuit 16, a current sensor 21 and a second lookup table 23 Respectively.

The power supply circuit 16 commonly supplies the high potential driving voltage Vdd_EL to the pixels of the display panel 10 through the power wiring.

The current sensor 21 senses the power wiring to which the high potential driving voltage Vdd_EL is applied to detect the panel current flowing through the display panel 10. [

The timing controller 11 compares the panel current (panel current after deterioration compensation) detected from the current sensor 21 with a previously stored initial panel current (panel current before deterioration compensation) to calculate the panel current increment. The luminance adjustment value is read from the first lookup table 22 with the panel current increment as a read address and the gate drive circuit 13 is controlled on the basis of the luminance adjustment value, The panel current flowing through the display panel 10 is reduced by an amount corresponding to the increase in panel current. The gate drive circuit 13 reduces the light emission period in one frame by adjusting the scan pulse and the emission pulse SCAN 'and EM' under the control of the timing controller 11.

Fig. 15 shows a fourth embodiment of the luminance control circuit.

Referring to Fig. 15, the luminance control circuit according to the fourth embodiment includes a timing controller 11, a power supply circuit 16, a current sensor 21, and a third lookup table 24. Fig.

The power supply circuit 16 commonly supplies the high potential driving voltage Vdd_EL to the pixels of the display panel 10 through the power wiring.

The current sensor 21 senses the power wiring to which the high potential driving voltage Vdd_EL is applied to detect the panel current flowing through the display panel 10. [

The timing controller 11 compares the panel current (panel current after deterioration compensation) detected from the current sensor 21 with a previously stored initial panel current (panel current before deterioration compensation) to calculate the panel current increment. The luminance adjustment value is read from the first lookup table 22 with the panel current increment as a read address and the video data to be applied to the pixels of the display panel 10 is lowered based on the luminance adjustment value (DATA ' ) To reduce the panel current flowing in the display panel 10 by the amount of the panel current increase.

As described above, the organic light emitting diode display device and the driving method thereof according to the present invention reduce the total luminance of the display panel by the increase of the panel current by the deterioration compensation, so that the power consumption, which is increased by the deterioration compensation, . Accordingly, the present invention can alleviate the phenomenon of acceleration of deterioration due to the deterioration compensation, and further reduce the power consumption and the risk of the overcurrent.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. For example, in the embodiment of the present invention, the configuration in which the entire luminance of the display panel is lowered by the amount of the panel current increase is described. However, the technical idea of the present invention includes a configuration in which the total luminance of the display panel is lowered do. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

10: Display panel 11: Timing controller
12: data driving circuit 13: gate driving circuit
14: Data line 15: Gate line
16: power supply circuit 21: current sensor
22,23,24: Lookup table

Claims (12)

Compensating the deterioration of the organic light emitting diode;
Comparing the first panel current flowing in the display panel after compensating for the deterioration with a second panel current flowing in the display panel before compensating for the deterioration, thereby obtaining a panel current increment; And
And lowering the total luminance of the display panel based on the panel current increment,
Wherein the driving current applied to each pixel is lowered by a value obtained by dividing the panel current increment by the total number of pixels of the display panel in lowering the total luminance of the display panel. delete The method according to claim 1,
In the step of lowering the total luminance of the display panel,
Reads the luminance adjustment value from the lookup table using the panel current increment as a read address and lowers the high potential driving voltage applied to the pixels of the display panel based on the luminance adjustment value, . The method according to claim 1,
In the step of lowering the total luminance of the display panel,
Reads the luminance adjustment value from the look-up table with the panel current increment as a read address, and adjusts the reference voltage applied to the pixels of the display panel based on the luminance adjustment value. Driving method. The method according to claim 1,
In the step of lowering the total luminance of the display panel,
The luminance adjustment value is read from the lookup table using the panel current increment as a read address and the scan pulse and the emission pulse applied to the pixels of the display panel are adjusted based on the luminance adjustment value, And the time required for the organic light emitting diode display is reduced. The method according to claim 1,
In the step of lowering the total luminance of the display panel,
Modulates the video data to be applied to the pixels of the display panel based on the luminance adjustment value, reading the luminance adjustment value from the lookup table using the panel current increment as a read address, . A display panel in which a plurality of pixels each having an organic light emitting diode are arranged;
A deterioration compensation circuit for compensating deterioration of the organic light emitting diode; And
Comparing the first panel current flowing in the display panel with the second panel current flowing in the display panel before compensating for the deterioration to obtain the panel current increment, And a luminance control circuit for lowering the total luminance of the display panel by lowering a driving current applied to each pixel by a value divided by the total number of pixels. delete 8. The method of claim 7,
Wherein the brightness control circuit comprises:
A current sensor for detecting the first panel current; And
The panel current increment is calculated by comparing the first panel current and the second panel current stored in advance, and the luminance adjustment value is read out from the lookup table using the panel current increment as a read address. Based on the luminance adjustment value And a power supply circuit for lowering a high potential driving voltage applied to the pixels of the display panel. 8. The method of claim 7,
Wherein the brightness control circuit comprises:
A current sensor for detecting the first panel current; And
The panel current increment is calculated by comparing the first panel current and the second panel current stored in advance, and the luminance adjustment value is read out from the lookup table using the panel current increment as a read address. Based on the luminance adjustment value And a power supply circuit for adjusting a reference voltage applied to the pixels of the display panel. 8. The method of claim 7,
Wherein the brightness control circuit comprises:
A current sensor for detecting the first panel current;
A gate driving circuit for applying a scan pulse and an emission pulse to the pixels of the display panel; And
The panel current increment is calculated by comparing the first panel current and the second panel current stored in advance, and the luminance adjustment value is read out from the lookup table using the panel current increment as a read address. Based on the luminance adjustment value And a timing controller for adjusting the scan pulse and the emission pulse through the control of one of the gate driving circuits to reduce a time occupied by the light emitting period during one frame period. 8. The method of claim 7,
Wherein the brightness control circuit comprises:
A current sensor for detecting the first panel current; And
The panel current increment is calculated by comparing the first panel current and the second panel current stored in advance, and the luminance adjustment value is read out from the lookup table using the panel current increment as a read address. Based on the luminance adjustment value And a timing controller for down-modulating video data to be applied to the pixels of the display panel.

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