CN103280188B - OLED compensation of ageing system and method - Google Patents

Abstract

The present invention relates to the technology of the display panel. The present invention solves the problem in the existing OLED device aging compensation system that requires a processor to perform calculations to perform aging compensation, and provides an OLED device aging compensation system and method, and its technical solution can be summarized as: OLED device aging compensation system, consisting of The input terminals of the first power supply, the second power supply and the reference power supply are respectively connected to the OLED pixel circuit, the analog-to-digital converter is connected to the OLED pixel circuit, the controller is connected to the analog-to-digital converter, the memory is connected to the controller, and the GAMMA correction module is connected to the memory The image signal input end is connected to the GAMMA correction module, the source drive module is connected to the GAMMA correction module, and the source drive module is connected to the OLED pixel circuit. The beneficial effect of the invention is that it does not occupy processor resources and is suitable for aging compensation of OLED devices.

Description

OLED device aging compensation system and method

technical field

The invention relates to the technology of the display panel, in particular to the technology of aging compensation of the OLED device in the AMOLED display panel.

Background technique

At present, TFT-LCD is the mainstream product in the field of flat panel display, but compared with LCD display, AMOLED display has lower power consumption, faster refresh rate, larger viewing angle, good low temperature resistance, light and thin screen body and does not require Advantages such as backlight source, so AMOLED displays have the most development potential in new flat panel displays.

Generally, an AMOLED display needs to use a display driver chip to convert digital display information sent by a processor or an external interface into an analog signal to control the pixel circuit on the panel to display images. The non-linear photoelectric characteristics of OLED will have a negative impact on the display effect, so the driver chip is integrated with a GAMMA voltage generation module to generate corrected GAMMA voltage, so as to eliminate the influence of OLED non-linear photoelectric characteristics and make the actual image as possible as possible. Show it for real.

The brightness of OLED increases with the increase of the current density flowing through it. At present, the main technology used is to control the current passing through the OLED device by encoding the voltage of the drive tube in the pixel drive circuit composed of thin film transistors in the AMOLED display panel to control the sub- The display brightness of the pixel point, but even if the same magnitude of current flows through the OLED device after aging, the brightness of the OLED light will decrease compared with the new pixel, so the curve response of the OLED corresponding to the pixel driving circuit will change after aging.

Therefore, in addition to compensation for display unevenness caused by TFT mismatch and deterioration of display effect caused by TFT aging on the display panel, it is also necessary to compensate for the aging of the OLED device itself.

In the prior art, the aging compensation system for the OLED device itself generally adopts detection parameters, caches the detection parameters and calculates the corresponding aging compensation parameters through the processor, and then performs aging of the OLED device according to the calculated aging compensation parameters. Compensation, but it is relatively troublesome to calculate the aging compensation parameters through the processor, and because the detection parameters are calculated through the processor every time, it takes up processor resources extremely.

Contents of the invention

The purpose of the present invention is to overcome the disadvantage that the current OLED device aging compensation system requires a processor to perform calculations to perform aging compensation, and to provide an OLED device aging compensation system and method.

The present invention solves the technical problem. The technical solution adopted is that the OLED device aging compensation system includes a reference power input terminal, an OLED pixel circuit, a first power supply and a second power supply, and the first power supply, the second power supply and the reference power supply input The terminals are respectively connected to the OLED pixel circuit. The OLED pixel circuit includes an OLED device, and is characterized in that it also includes an analog-to-digital converter, a controller, a memory, a GAMMA correction module, an image signal input terminal, and a source driver module. The converter is connected to the OLED pixel circuit, the controller is connected to the analog-to-digital converter, the memory is connected to the controller, the GAMMA correction module is connected to the memory, the image signal input terminal is connected to the GAMMA correction module, the source driver module is connected to the GAMMA correction module, The source drive module is connected to the OLED pixel circuit;

The analog-to-digital converter is used to convert the detected second node voltage into a digital code and then transmit it to the controller, and the second node voltage is the anode voltage of the OLED device when the reference power input terminal provides current during the detection phase;

The controller is used to control the reading of data in the memory to the GAMMA correction module according to the digital code of the second node voltage transmitted by the analog-to-digital converter;

The information of each reference voltage point of the GAMMA curve under different aging degrees is stored in the memory, and the corresponding reference voltage point information is selected according to the control of the controller to be output to the GAMMA correction module;

The image signal input terminal is used to input an image signal to the GAMMA correction module;

The GAMMA correction module is used to generate a number of grayscale voltages corresponding to the input image signal as image data information converted into analog signals according to different reference voltage point information transmitted from the memory, and transmit them to the source driver module;

The source driver module pushes the image data information of the analog signal transmitted by the GAMMA correction module to the OLED pixel circuit, and then drives the OLED device to emit light.

Specifically, the OLED pixel circuit includes a first thin film transistor, a second thin film transistor, a third thin film transistor, a fourth thin film transistor, a fifth thin film transistor, a sixth thin film transistor, an OLED device, a capacitor, and a first control signal input terminal , the second control signal input end, the third control signal input end, the fourth control signal input end and the fifth control signal input end, the gate of the first thin film transistor is connected to the first control signal input end, and the source is connected to the first control signal input end. The source driver module is connected, the drain is connected to the drain of the second thin film transistor through a capacitor, and is connected to the gate of the third thin film transistor, the gate of the second thin film transistor is connected to the second control signal input terminal, and the second thin film The source of the transistor is connected to the drain of the third thin film transistor, the source of the third thin film transistor is connected to the first power supply, the gate of the fourth thin film transistor is connected to the third control signal input terminal, and its source is connected to the third thin film transistor The drain of the transistor is connected, the drain is connected to the anode of the OLED device, the gate of the fifth thin film transistor is connected to the fifth control signal input terminal, its source is connected to the anode of the OLED device, and the drain is connected to the analog-to-digital converter, The gate of the sixth thin film transistor is connected to the input terminal of the fourth control signal, the source thereof is connected to the input terminal of the reference power supply, the drain thereof is connected to the anode of the OLED device, and the cathode of the OLED device is connected to the second power supply.

Still further, the memory stores the information of each reference voltage point of the GAMMA curve under different aging degrees, and the information of each reference voltage point of the GAMMA curve includes the highest reference voltage of GAMMA.

OLED device aging compensation method, is characterized in that, comprises the steps:

Step 1, storing in the memory the information of the reference voltage point of the GAMMA curve adapted to different aging degrees;

Step 2, detecting the anode voltage of the OLED device when the current is supplied from the input terminal of the reference power supply, and converting the detected voltage into a digital code and transmitting it to the controller;

Step 3, the controller controls the data in the memory, selects the corresponding GAMMA curve reference voltage point information in the memory and reads it out to the GAMMA correction module;

Step 4, the GAMMA correction module adjusts the GAMMA curve so that the gray scale of the signal voltage adapts to the brightness change of the aged OLED device.

Specifically, in step 1, the acquisition method of the reference voltage point information of the GAMMA curve adapted to the different aging degrees is as follows:

Step 101, the screen manufacturer provides voltages and luminances corresponding to different aging degrees of OLED devices under constant current conditions;

Step 102, by calculating the ratio of the current density to the luminance, and calculating the corresponding values of each reference voltage point according to the ratio.

The beneficial effect of the present invention is that, in the solution of the present invention, through the above-mentioned OLED device aging compensation system and method, the aging compensation of the OLED device can be realized without connecting the system to the processor, no longer occupying processor resources, and improving the performance of the overall system. operating efficiency.

Description of drawings

Fig. 1 is a system block diagram of the OLED device aging compensation system of the present invention.

Fig. 2 is a time sequence diagram of one cycle of sub-pixels in the OLED device aging compensation system according to the embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of the OLED device aging compensation system of the present invention at the stage T1 in FIG. 2 .

FIG. 4 is an equivalent circuit diagram of the OLED device aging compensation system of the present invention at the stage T2 in FIG. 2 .

FIG. 5 is an equivalent circuit diagram of the OLED device aging compensation system of the present invention at stage T3 in FIG. 2 .

Among them, C is a capacitor, ELVDD is the first power supply, ELVSS is the second power supply, OLED is the OLED device, N1 is the first node, N2 is the second node, M1 is the first thin film transistor, M2 is the second thin film transistor, M3 is the third thin film transistor, M4 is the fourth thin film transistor, M5 is the fifth thin film transistor, M6 is the sixth thin film transistor, S1 is the first control signal input terminal, S2 is the second control signal input terminal, and S3 is the third control signal input terminal. Signal input terminals, S4 is the fourth control signal input terminal, and S5 is the fifth control signal input terminal.

Detailed ways

The technical solution of the present invention will be described in detail below in combination with the embodiments and the accompanying drawings.

The system block diagram of the OLED device aging compensation system of the present invention is shown in FIG. 1 . The OLED device aging compensation system of the present invention includes a reference power supply input terminal, an OLED pixel circuit, a first power supply ELVDD, a second power supply ELVSS, an analog-to-digital converter, a controller, a memory, a GAMMA correction module, an image signal input terminal and a source In the drive module, the first power supply ELVDD, the second power supply and the reference power supply input terminals are respectively connected to the OLED pixel circuit, the OLED pixel circuit includes an OLED device, the analog-to-digital converter is connected to the OLED pixel circuit, the controller is connected to the analog-to-digital converter, The memory is connected to the controller, the GAMMA correction module is connected to the memory, the image signal input terminal is connected to the GAMMA correction module, the source driver module is connected to the GAMMA correction module, and the source driver module is connected to the OLED pixel circuit, wherein the analog-to-digital converter is used for Convert the detected second node voltage into a digital code and then transmit it to the controller. The second node N2 voltage is the anode voltage of the OLED device when the current is supplied by the reference power input terminal during the detection phase; The transmitted digital code of the second node N2 voltage controls the data in the memory to be read to the GAMMA correction module; the memory stores the information of each reference voltage point of the GAMMA curve under different aging degrees, and selects the corresponding reference voltage point according to the control of the controller The information is output to the GAMMA correction module; the image signal input terminal is used to input the image signal to the GAMMA correction module; the GAMMA correction module is used to generate several grayscale voltages corresponding to the input image signal according to the information of different reference voltage points transmitted from the memory as conversion The image data information of the analog signal is transmitted to the source driver module; the source driver module pushes the image data information of the analog signal transmitted by the GAMMA correction module to the OLED pixel circuit, and then drives the OLED device to emit light.

In the OLED device aging compensation method of the present invention, at first store in memory the GAMMA curve reference voltage point information that adapts under different aging degrees, during detection, detect the anode voltage of OLED device when the current is provided by the reference power supply input terminal, and will detect The voltage is converted into digital codes and transmitted to the controller. The controller then controls the data in the memory, selects the corresponding GAMMA curve reference voltage point information in the memory, and reads it to the GAMMA correction module. Finally, the GAMMA correction module adjusts the GAMMA curve to make the signal voltage The gray scale is adapted to the brightness variation of the aged OLED device.

Example

A system block diagram of an OLED device aging compensation system according to an embodiment of the present invention is shown in FIG. 1 . The OLED device aging compensation system of the present invention includes a reference power supply input terminal, an OLED pixel circuit, a first power supply ELVDD, a second power supply ELVSS, an analog-to-digital converter, a controller, a memory, a GAMMA correction module, an image signal input terminal and a source The drive module, the first power supply ELVDD, the second power supply ELVSS and the input terminals of the reference power supply are respectively connected to the OLED pixel circuit, the OLED pixel circuit includes OLED devices, the analog-to-digital converter is connected to the OLED pixel circuit, and the controller is connected to the analog-to-digital converter , the memory is connected to the controller, the GAMMA correction module is connected to the memory, the image signal input terminal is connected to the GAMMA correction module, the source driver module is connected to the GAMMA correction module, the source driver module is connected to the OLED pixel circuit, wherein the analog-to-digital converter is used After converting the detected voltage of the second node N2 into a digital code, it is transmitted to the controller, and the voltage of the second node N2 is the anode voltage of the OLED device when the current is supplied by the reference power input terminal during the detection phase; the controller is used to The digital code of the second node voltage transmitted by the converter controls the data in the memory to be read to the GAMMA correction module; the memory stores the information of each reference voltage point of the GAMMA curve under different aging degrees, and selects the corresponding reference voltage according to the control of the controller The point information is output to the GAMMA correction module, and the information of each reference voltage point of the GAMMA curve includes the highest reference voltage of GAMMA; the image signal input terminal is used to input the image signal to the GAMMA correction module; the GAMMA correction module is used for different reference voltage points transmitted from the memory The information generates a number of grayscale voltages corresponding to the input image signal as the image data information converted into an analog signal, and transmits it to the source driver module; the source driver module pushes the image data information of the analog signal transmitted by the GAMMA correction module to The OLED pixel circuit drives the OLED device to emit light.

In this example, the OLED pixel circuit includes a first thin film transistor M1, a second thin film transistor M2, a third thin film transistor M3, a fourth thin film transistor M4, a fifth thin film transistor M5, a sixth thin film transistor M6, an OLED device, a capacitor C, a A control signal input terminal S1, a second control signal input terminal S2, a third control signal input terminal S3, a fourth control signal input terminal S4, and a fifth control signal input terminal S5, the gate of the first thin film transistor M1 and The first control signal input terminal S1 is connected, the source is connected to the source driver module, the drain is connected to the drain of the second thin film transistor M2 through a capacitor C, and is connected to the gate of the third thin film transistor M3, and the second thin film transistor The gate of M2 is connected to the second control signal input terminal S2, the source of the second thin film transistor M2 is connected to the drain of the third thin film transistor M3, the source of the third thin film transistor M3 is connected to the first power supply ELVDD, and the fourth The gate of the thin film transistor M4 is connected to the third control signal input terminal S3, its source is connected to the drain of the third thin film transistor M3, the drain is connected to the anode of the OLED device, and the gate of the fifth thin film transistor M5 is connected to the fifth The control signal input terminal S5 is connected, its source is connected to the anode of the OLED device, its drain is connected to the analog-to-digital converter, the gate of the sixth thin film transistor M6 is connected to the fourth control signal input terminal S4, and its source is connected to the reference power supply The input end is connected, the drain is connected with the anode of the OLED device, and the cathode of the OLED device is connected with the second power supply ELVSS.

When in use, first store in the memory the information of the reference voltage points of the GAMMA curves adapted to different degrees of aging. The method of obtaining the information of the reference voltage points of the GAMMA curves adapted to the different degrees of aging is: The voltage and brightness corresponding to different aging degrees of OLED devices under the conditions, and then by calculating the ratio of current density to brightness, the corresponding value of each reference voltage point is calculated according to the ratio; during detection, when the current is supplied by the input terminal of the reference power supply The anode voltage of the OLED device, and convert the detected voltage into a digital code and transmit it to the controller. The controller then controls the data in the memory, selects the corresponding GAMMA curve reference voltage point information in the memory, and reads it to the GAMMA correction module. Finally, the GAMMA The correction module adjusts the GAMMA curve to adapt the grayscale of the signal voltage to the brightness variation of the aged OLED device.

The specific operation example is as follows: In this example, the timing diagram of one sub-pixel cycle in the OLED device aging compensation system is shown in Figure 2. In this example, one sub-pixel cycle is divided into three stages: T1, T2 and T3. The first stage is the compensation stage of the threshold value of the third thin film transistor in the OLED pixel circuit, and at the same time, the aging detection and compensation of the OLED device are performed; the second stage, the image signal is sent to the panel through the adjusted GAMMA curve to generate a signal analog signal voltage (OLED pixel circuit ), stored in the capacitor C; the third stage is the light-emitting display stage of the OLED device. The working conditions of the three-stage circuit will be introduced in detail below.

As shown in FIG. 3 is the equivalent circuit diagram of the T1 stage. In this stage, the voltage of the second node N2 is detected and the GAMMA curve is adjusted. At the same time, the OLED pixel circuit partially compensates the threshold value of the third thin film transistor M3. At this time, the second, fourth and fifth control signals are low level, the second M2, the fifth M5 and the sixth thin film transistor M6 are turned on; the first and third control signals are high level, the first M1 and The fourth thin film transistor M4 is cut off; therefore, no image signal is input to the GAMMA correction module in the T1 stage, the third thin film transistor M3 is turned on but the leakage current is zero, so the gate potential of the third thin film transistor M3 is the first power supply ELVDD minus the third Thin-film transistor M3 threshold (ELVDD-V _{th_M3} ); at the same time, the current provided by the input terminal of the reference power supply passes through the OLED device, and the analog-to-digital converter converts the detected voltage of the second node N2 into a binary digital code, outputs it to the controller, and then controls The device outputs address information, reads the information corresponding to the GAMMA reference voltage point under the detected aging condition from the memory, adjusts the GAMMA curve through the GAMMA correction module, and waits for the input of image data.

As shown in Figure 4 is the equivalent circuit diagram of the T2 stage, which is the stage of inputting the image signal voltage to the gate of the third thin film transistor M3, as can be seen from Figure 2, the first control signal is low level, and the first thin film transistor M1 conducts Through, the adjusted image signal voltage Vdata is input to the panel (OLED pixel circuit), so that the voltage of the capacitor C is ELVDD-V _{th_M3} -Vdata, and then Vdata becomes low level. Since the voltage of the capacitor C cannot be mutated, the first The potential of the gate of the three thin film transistors M3 becomes ELVDD-V _{th_M3} -Vdata; the second control signal, the third control signal, the fourth control signal and the fifth control signal are at high level, the second M2, the fourth M4, the The fifth M5 and the sixth thin film transistor M6 are cut off, no current flows through the OLED device, and the aging detection of the OLED device and the adjustment of the GAMMA curve have been completed in the T1 stage.

As shown in Figure 5, it is the T3 stage, which is the light-emitting stage of the OLED device. It can be seen from Figure 2 that the first, second, fourth and fifth control signals are at high level, and the first M1, the second M2, the The fifth M5 and the sixth thin film transistor M6 are turned off, the third control signal is at low level, and the fourth thin film transistor M4 is turned on. At this time, the capacitor C keeps the potential of the gate of the third thin film transistor M3 (that is, the first node N1) at ELVDD-V _{th_M3} -Vdata, the driving current generated by the third thin film transistor M3 passes through the OLED device, and the OLED device keeps emitting light.

The compensation method adopted in the present invention stores the GAMMA curve reference voltage point information corresponding to various degrees of aging of the OLED device in the memory, and adjusts the entire GAMMA curve after detection to compensate for the brightness deviation caused by the aging of the OLED device. This compensation method does not need to input the detected voltage information into the processor for calculation each time, which simplifies the compensation process.

Those skilled in the art will appreciate that the examples described here are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and examples. The above embodiments are only used to illustrate the technical solution of the present invention. Those of ordinary skill in the art should understand that the technical solutions in this direction can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions in this aspect, and all should be covered by the protection scope of the present invention.

Claims (5)

1.OLED device aging bucking-out system, comprise reference power source input end, OLED pixel circuit, first power supply and second source, described first power supply, second source and reference power source input end are connected with OLED pixel circuit respectively, OLED pixel circuit comprises OLED, it is characterized in that, also comprise analog to digital converter, controller, storer, GAMMA correction module, picture signal input end and source drive module, described analog to digital converter is connected with OLED pixel circuit, controller is connected with analog to digital converter, storer is connected with controller, GAMMA correction module is connected with storer, picture signal input end is connected with GAMMA correction module, source drive module is connected with GAMMA correction module, source drive module is connected with OLED pixel circuit,

It is be transferred to controller after numerical code by the Section Point voltage transitions detected that described analog to digital converter is used for, and described Section Point voltage is the anode voltage of OLED when detection-phase provides electric current by reference power source input end;

Described controller is used for according to the data reading in the numerical code control store of the next Section Point voltage of analog to digital converter transmission to GAMMA correction module;

Store each reference voltage dot information of GAMMA curve under different degree of aging in described storer, select corresponding reference voltage dot information to export to GAMMA correction module according to the control of controller;

Described picture signal input end is used for GAMMA correction module received image signal;

The different reference voltage dot informations that described GAMMA correction module is used for coming according to memory transfer produce some grayscale voltages corresponding with received image signal as the image data information being converted to simulating signal, and are transferred to source drive module;

The image data information of the simulating signal that the transmission of GAMMA correction module comes is pushed to OLED pixel circuit by described source drive module, and then driving OLED device is luminous.

2. OLED compensation of ageing system as claimed in claim 1, it is characterized in that, described OLED pixel circuit comprises the first film transistor, second thin film transistor (TFT), 3rd thin film transistor (TFT), 4th thin film transistor (TFT), 5th thin film transistor (TFT), 6th thin film transistor (TFT), OLED, electric capacity, first control signal input end, second control signal input end, 3rd control signal input end, 4th control signal input end and the 5th control signal input end, the grid of described the first film transistor is connected with the first control signal input end, source electrode is connected with source drive module, drain electrode is connected by the drain electrode of electric capacity with the second thin film transistor (TFT), and be connected with the grid of the 3rd thin film transistor (TFT), the grid of the second thin film transistor (TFT) is connected with the second control signal input end, the source electrode of the second thin film transistor (TFT) is connected with the drain electrode of the 3rd thin film transistor (TFT), the source electrode of the 3rd thin film transistor (TFT) is connected with the first power supply, the grid of the 4th thin film transistor (TFT) is connected with the 3rd control signal input end, its source electrode is connected with the drain electrode of the 3rd thin film transistor (TFT), drain electrode is connected with the anode of OLED, the grid of the 5th thin film transistor (TFT) is connected with the 5th control signal input end, its source electrode is connected with the anode of OLED, drain electrode is connected with analog to digital converter, the grid of the 6th thin film transistor (TFT) is connected with the 4th control signal input end, its source electrode is connected with reference power source input end, drain electrode is connected with the anode of OLED, the negative electrode of OLED is connected with second source.

3. OLED compensation of ageing system as claimed in claim 1 or 2, it is characterized in that, store in described storer under different degree of aging in each reference voltage dot information of GAMMA curve, each reference voltage dot information of described GAMMA curve comprises the highest reference voltage of GAMMA.

The compensation method of 4.OLED device aging, is characterized in that, comprise the steps:

Step 1, store the GAMMA curve reference voltage dot information adapted under different degree of aging in memory;

Step 2, detect the anode voltage of OLED when providing electric current by reference power source input end, and be that numerical code is transferred to controller by the voltage transitions of detection;

Data in step 3, controller control store, GAMMA curve reference voltage dot information corresponding in selection memory reads to GAMMA correction module;

Step 4, GAMMA correction module adjustment GAMMA curve with make the gray scale of signal voltage adapt to aging after the brightness change of OLED.

5. OLED aging compensation approach as claimed in claim 4, it is characterized in that, in step 1, the acquisition methods of the GAMMA curve reference voltage dot information adapted under described different degree of aging is:

Step 101, screen production firm provide the different voltage corresponding to degree of aging of OLED under constant current conditions and brightness;

Step 102, by the ratio of calculating current density with brightness, obtain the value of corresponding each reference voltage point according to this ratio calculation.