The present application is a National Phase of International Application Number PCT/CN2017/112475, filed Nov. 23, 2017, and claims the priority of China Application No. 201710949708.5, filed Oct. 11, 2017.
The disclosure relates to an organic light emitting diode display technical field, and more particularly to a temperature compensation circuit and method for a display panel and a display panel.
Compared with liquid crystal displays (LCDs), organic light emitting diode (OLED) devices have the advantages such as fast response, light weight, no limitation of viewing angle, high contrast ratio and so on, and the organic light emitting diode (OLEO) devices are considered as the main research focuses of the display panel in recent years. According to the driving method of the organic light emitting diode, it can be roughly divided into a passive organic light emitting diode (PMOLED) panel and an active organic light emitting diode (AMOLED) panel. Wherein AMOLED panel for high-resolution and large size display panel. The pixel brightness of AMOLED panel is proportional to the conduction current of the organic light-emitting diode, and the amount of the conduction current is determined by the transistor. In the practice process, the temperature of the AMOLED panel increases, the threshold voltage of the transistor will gradually reduce, and the driving current of the transistor for driving the organic light-emitting diode is increased, so that the conduction current flowing through the organic light-emitting diode is increased. However, the AMOLED panel contains a large amount of organic materials to deteriorate the AMOLED panel under high temperature and high current conditions easily, thereby shortening the service life of the AMOLED panel.
In order to solve the above technical problem, the prior art approach is to set a temperature sensor on the AMOLED panel. The temperature sensor detects the working temperature of the AMOLED panel and feedback to the control circuit, the control circuit reduces the conduction current through the organic light-emitting diode by reducing the driving current of the transistor uniformly to achieve the purpose for extending the service life of the AMOLED panel by the temperature compensation for the AMOLED panel.
However, an additional temperature sensor needs to be added for the temperature compensation in the prior art, so the production cost of the display panel will be increased.
A technical problem to be solved by the disclosure is to provide a temperature compensation circuit and method for a display panel and a display panel, so the temperature compensation of the display panel can be realized without an additional temperature sensor so as to extend the service life of the display panel.
To achieve the above object, according to one aspect, the embodiment of the disclosure provides a temperature compensation circuit for a display panel, including:
To achieve the above object, according to another aspect, the embodiment of the disclosure provides a display panel, including:
The beneficial effects of the disclosure are as follows, a temperature compensation circuit and method for a display panel and a display panel provided by the disclosure obtain a current threshold voltage of a transistor of the pixel circuit, further obtain a current voltage difference between the current threshold voltage and an initial threshold voltage, then obtain a current compensation gain matching the current voltage difference according to a predetermined related data of a voltage difference and a compensation gain, and controls the driving circuit to drive the pixel circuit by using the current compensation gain. By practice of the disclosure, the temperature compensation for a display panel could be achieved without the additional temperature sensor, so the service life of the display panel could be extended.
Certain terms are used throughout the following descriptions and claims to refer to particular system components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. The disclosure is described in detail below with references to the accompanying drawings and specific embodiments,
The control circuit 111, the driving circuit 112 and the pixel circuit 13 are sequentially electrically coupled, the detection circuit 112 respectively electrically couple to the control circuit 111 and the pixel circuit 13.
Specifically, please refer to
Wherein, a gate of the first transistor T1 electrically connects to a first control signal line WR, a source of the first transistor electrically connects to a data signal line Vdata, a drain of the first transistor electrically connects to a first node A1; a gate of the second transistor T2 electrically connects to the first node A1, a source of the second transistor T2 electrically connects to a second node A2, a drain of the second transistor T2 connects to a positive voltage of a power source VDD; a gate of the third transistor T3 electrically connects to a second control signal line RD, a source of the third transistor T3 electrically connects to the second node A2, a drain of the third transistor T3 electrically connects to a detection signal line Monitor; an end of the storage capacitor C electrically connects to the first node A1, another end of the storage capacitor C electrically connects to the second node A2; an anode of the organic light emitting diode D electrically connects to the second node A2, a cathode of the organic light emitting diode D electrically connects to a negative voltage of the power source Vss.
Wherein, the first control signal line WR, the data signal line Vdata and the second signal line RD respectively electrically connect to the driving circuit 12, the detection signal line Monitor and the detection circuit 112.
Wherein, the control circuit 111, the detection circuit 112 and the driving circuit 12 are circuit modules in an existing timing controller (TCON). Those skilled in the art can understand that the timing controller is mainly composed of a timing generator, a display memory, a management circuit and a control circuit, and the temperature compensation function is realized by using the existing timing controller without adding extra hardware cost.
The detection circuit 112 is configured to obtain a current threshold voltage Vth of the transistor of the pixel circuit 13. Specifically, the detection circuit 112 obtains the current threshold voltage Vth of the driving transistor, i.e. the second transistor T2 of each of the sub-pixel driving circuits 131 through the detection signal line Monitor.
Specifically, When the first transistor T1 and the third transistor T3 are turned on at the same time, the data voltage signal applied to the data signal line Vdata and the reference voltage signal applied to the detection signal line Monitor are written into both ends of the storage capacitor C respectively. At this moment, the second transistor T2 turns on. Then, the reference voltage signal is disconnected, and the current charges the parasitic capacitance of the detection signal line Monitor through the third transistor T3 until the voltage difference across the storage capacitor C is the current threshold voltage Vth, the second transistor T2 is turned off. In this moment, the detection circuit 112 reads the voltage on the detection signal line Monitor as the current threshold voltage Vth of the driving transistor.
The control circuit 111 obtains a current voltage difference ΔVth between the current threshold voltage Vth and an initial threshold voltage Vth0, obtains a current compensation gain G matching the current voltage difference ΔVth according to a predetermined related data of a voltage difference ΔVth and a compensation gain G, and controls the driving circuit 12 to drive the pixel circuit 13 by using the current compensation gain G to compensate an impact of temperature variation on the pixel circuit 13.
Selectively, the related data of predetermined voltage difference and compensation gain is obtained by the following steps, including: obtaining a relation between a threshold voltage of the transistor of the pixel circuit 13 and a temperature, and a relation between a mobility of the transistor of the pixel circuit 13 and the temperature by experiment, establishing the predetermined related data of the temperature, the voltage difference and the compensation gain, wherein the compensation gain is obtained through a combination of the threshold voltage, the mobility and the temperature.
Please refer to
As shown in
Please refer to
As shown in FIG, 4, with the increase of temperature T, the mobility μFE of Sample A, Sample B and Sample C is increasing.
Wherein, the variation of the threshold voltage of the transistor under different operating temperatures can be estimated, i.e. a predetermined related data of a voltage difference and a compensation gain to form a look-up table by experimentally measuring the threshold voltage and the temperature of the transistor in the pixel circuit and the relationship between the mobility and the temperature.
Selectively, after the control circuit 111 obtained the current voltage difference ΔVth between the current threshold voltage Vth and the initial threshold voltage Vth0, further determines whether the current voltage difference ΔVth is less than zero, if and only if the current voltage difference ΔVth is less than zero, obtains the current compensation gain G matching the current voltage difference ΔVth according to the predetermined related data of the voltage difference ΔVth and the compensation gain G.
Those skilled in the art can understand that when the current voltage difference ΔVth is less than zero, it indicates that the temperature of the transistor in the pixel circuit 13 is increasing, that is, temperature compensation is needed. On the other hand, when the current voltage difference ΔVth is greater than or equal to zero, the temperature of the transistor in the pixel circuit 13 is decreased or remains unchanged, that is, no temperature compensation is required at this time.
Step S101: obtaining a current threshold voltage of a transistor of a pixel circuit.
In step S101, the pixel circuit includes a plurality of sub-pixel driving circuits arranged in matrix, wherein each of the sub-pixel driving circuits is configured to drive corresponding organic light emitting diode in the display panel, each of the sub-pixel driving circuits includes a transistor configured to drive corresponding organic light emitting diode.
Wherein, obtaining the current threshold voltage of the transistor in the pixel circuit of the display panel is also obtaining the current threshold voltage of the transistor driving each organic light emitting diode in the display panel respectively.
Step S102: obtaining a current voltage difference between the current threshold voltage and an initial threshold voltage, and determining whether the current voltage difference is less than zero, if yes, step S103 is executed; otherwise, step S101 is executed.
In step S102, if the current voltage difference ΔVth is less than zero, it indicates that the temperature of the transistor driving the organic light emitting diode is increasing, that is, temperature compensation is needed. On the other hand, when the current voltage difference ΔVth is greater than or equal to zero, the temperature of the transistor driving the organic light emitting diode is decreased or remains unchanged, that is, no temperature compensation is required at this time.
Those skilled in the art can understand that since the pixel circuit includes a plurality of sub-pixel driving circuits arranged in matrix, three different situations will occur: the current voltage differences of the transistors in all the sub-pixel driving circuits in the pixel circuit are all less than zero, or the current voltage differences of the transistors in all the sub-pixel driving circuits in the pixel circuit are all greater than or equal to zero, or the current voltage difference of the transistors in the partial sub-pixel driving circuits in the pixel circuit is less than zero and the current voltage difference of the transistors in the remaining sub-pixel driving circuit is greater than or equal to zero.
In other words, there are three different situations when temperature compensation is performed: temperature compensation is performed on all the transistors driving the organic light emitting diodes in the display panel, or temperature compensation of the transistors driving the organic light emitting diodes in the display panel is not required, or temperature compensation is performed on the partial transistors driving the organic light emitting diodes in the display panel and the remaining transistors the organic light emitting diodes do not need temperature compensation.
Step S103: obtaining a current compensation gain matching the current voltage difference according to a predetermined related data of a voltage difference and a compensation gain.
In step S103, the related data of predetermined voltage difference and compensation gain is obtained by the following steps, including: obtaining a relation between a threshold voltage of the transistor of the pixel circuit and a temperature, and a relation between a mobility of the transistor of the pixel circuit and the temperature by experiment, establishing the predetermined related data of the temperature, the voltage difference and the compensation gain, wherein the compensation gain is obtained through a combination of the threshold voltage, the mobility and the temperature.
Step S104: controlling the driving circuit to drive the pixel circuit by using the current compensation gain to compensate an impact of temperature variation on the pixel circuit.
In step S104, since the driving current of driving the sub-pixel is related to the data signal voltage, so this feature can be used to adjust the amount of the driving current to achieve the technical effect of compensating for the impact of the temperature variation on the pixel circuit.
Take the circuit diagram shown in
The beneficial effects of the disclosure are as follows, a temperature compensation circuit and method for a display panel and a display panel provided by the disclosure obtain a current threshold voltage of a transistor of the pixel circuit, further obtain a current voltage difference between the current threshold voltage and an initial threshold voltage, then obtain a current compensation gain matching the current voltage difference according to a predetermined related data of a voltage difference and a compensation gain, and controls the driving circuit to drive the pixel circuit by using the current compensation gain. By practice of the disclosure, the temperature compensation for a display panel could be achieved without the additional temperature sensor, so the service life of the display panel could be extended. In addition, the disclosure can realize the temperature compensation for the single transistor for driving the organic light-emitting diodes in the display panel respectively, so as to improve the precision of the temperature compensation, and the compensation effect is better.
The foregoing contents are detailed description of the disclosure in conjunction with specific preferred embodiments and concrete embodiments of the disclosure are not limited to these descriptions. For the person skilled in the art of the disclosure, without departing from the concept of the disclosure, simple deductions or substitutions can be made and should be included in the protection scope of the application.
Number | Date | Country | Kind |
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2017 1 0949708 | Oct 2017 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2017/112475 | 11/23/2017 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/071735 | 4/18/2019 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
20130083000 | Toyomura et al. | Apr 2013 | A1 |
20140168041 | Chen et al. | Jun 2014 | A1 |
20140176400 | Park et al. | Jun 2014 | A1 |
20150154908 | Nam et al. | Jun 2015 | A1 |
20160125811 | Park et al. | May 2016 | A1 |
Number | Date | Country |
---|---|---|
102654973 | Sep 2012 | CN |
106409231 | Feb 2017 | CN |
106935192 | Jul 2017 | CN |
106991969 | Jul 2017 | CN |
2000294154 | Oct 2010 | JP |
20010039316 | May 2001 | KR |
Number | Date | Country | |
---|---|---|---|
20190108792 A1 | Apr 2019 | US |