This application claims the priority of Chinese Patent Application No. 202310545136.X, filed on May 15, 2023, the disclosure of which is incorporated herein by reference in its entirety.
The present application relates to the field of display technology, and specifically relates to a compensation method for a pixel circuit, and a display panel.
External compensation pixel circuits usually need to compensate the data signal to obtain the desired display brightness. However, the existing compensation process needs to be implemented based on more compensation data, which in turn requires more storage resources.
This application provides a compensation method for a pixel circuit and a display panel to alleviate the technical problem that storage resources are excessively occupied due to large amounts of compensation data.
In a first aspect, a compensation method for a pixel circuit is disclosed, compensation method comprises steps of: obtaining a nonlinear function of the pixel circuit, wherein the nonlinear function is a relationship curve between a voltage transmission loss ratio and a voltage of a data signal, the voltage transmission loss ratio is a ratio of a second gate-source voltage difference of a driving transistor in the pixel circuit in a light-emitting phase to a first gate-source voltage difference of the driving transistor in a writing phase; converting the nonlinear function into a corresponding linear function which is a relationship curve between the first gate-source voltage difference and the second gate-source voltage difference; obtaining a compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference.
In some embodiments, the step of converting the nonlinear function into the corresponding linear function which is the relationship curve between the first gate-source voltage difference and the second gate-source voltage difference comprises steps of: setting the voltage transmission loss ratio, the first gate-source voltage difference and the second gate-source voltage difference as Efficiency, Vgs@write and Vgs@emission, respectively; converting the nonlinear function into a following intermediate relationship:
In some embodiments, the step of converting the nonlinear function into the corresponding linear function which is the relationship curve between the first gate-source voltage difference and the second gate-source voltage difference further comprises steps of: converting the intermediate relationship into the linear function as follows:
In some embodiments, the step of obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference comprises steps of: storing k, b; obtaining the compensated first gate-source voltage difference according to k, b, the redetermined second gate-source voltage difference and the linear function.
In some embodiments, the step of converting the nonlinear function into the corresponding linear function which is the relationship curve between the first gate-source voltage difference and the second gate-source voltage difference comprises steps of: dividing the data signal into multiple grayscale ranges according to a voltage magnitude of the data signal; converting the nonlinear function into the multiple linear functions in different grayscale ranges.
In some embodiments, the step of converting the nonlinear function into a corresponding linear function which is the relationship curve between the first gate-source voltage difference and the second gate-source voltage difference further comprises steps of: constructing the multiple grayscale ranges including a low grayscale range and a high grayscale range; converting the nonlinear function into a first linear function in the low grayscale range and a second linear function in the high grayscale range.
In some embodiments, the step of converting the nonlinear function into the corresponding linear function which is the relationship curve between the first gate-source voltage difference and the second gate-source voltage difference further comprises steps of: determining the first linear function as Vgs@emission=k1*Vgs@write+b1, where k1 and b1 are constants; determining the second linear function as Vgs@emission=k2*Vgs@write+b2, where k2 and b2 are all constants.
In some embodiments, the step of obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference comprises steps of: obtaining the compensated first gate-source voltage difference in the low grayscale range according to k1, b1, the redetermined second gate-source voltage difference and the linear function; obtaining the compensated first gate-source voltage difference in the high grayscale range according to k2, b2, the redetermined second gate-source voltage difference and the linear function;
In some embodiments, after the step of obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference, the compensation method comprises steps of: determining the compensated data signal according to the compensated first gate-source voltage difference; charging the pixel circuit according to the voltage of the compensated data signal.
In a second aspect, the present application provides a display panel that performs the compensation method in at least one embodiment.
The pixel circuit compensation method and display panel provided by this application firstly obtain the nonlinear function of the pixel circuit, then convert the nonlinear function into the corresponding linear function, and then obtain the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference. Since nonlinear functions require more compensation data and have larger errors than linear functions, using the converted linear function for compensation can reduce the required storage resources and improve the accuracy of compensation.
In order to more clearly illustrate the technical solution in the embodiment of the present disclosure, the following will be a brief introduction to the drawings required in the description of the embodiment. Obviously, the drawings described below are only some embodiments of the present disclosure, for those skilled in the art, without the premise of creative labor, may also obtain other drawings according to these drawings.
To help a person skilled in the art better understand the solutions of the present disclosure, the following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present disclosure.
In addition, the term “first”, “second” are for illustrative purposes only and are not to be construed as indicating or imposing a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature that limited by “first”, “second” may expressly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of “plural” is two or more, unless otherwise specifically defined.
Then, the gate-source voltage difference (Vg-Vs) of the driving transistor T1 during the writing phase is Vgs@write (Vdata-Vref) as shown in
Ideally, Vgs@write should be equal to Vgs@emission, but due to the unequal parasitic capacitances of the gate and source, the gate potential (Vg) of the driving transistor T1 is not raised as shown by the dotted line in
Wherein, in
Wherein, the data line is configured to transmit the data signal (data). The scan line is configured to transmit the scan signal (WR).
The pixel circuit may further include a storage capacitor Cst. One end of the storage capacitor Cst is connected to the gate of the driving transistor T1, and the other end of the storage capacitor Cst is connected to the source of the driving transistor T1.
The pixel circuit may further include a light-emitting device, the anode of the light-emitting device is connected to the source of the driving transistor T1, and the cathode of the light-emitting device is connected to the negative power line.
Wherein, the negative power line is configured to transmit the negative power signal VSS.
The pixel circuit may further include a sensing transistor T3. One of the source or drain of the sensing transistor T3 is connected to the source of the driving transistor T1, and the other of the source or drain of the sensing transistor T3 is connected to the sensing line. The gate of the sensing transistor T3 is connected to the readout control line. The readout control line is configured to transmit the scan signal RD.
The pixel circuit may further include a first switch T5. A first end of the first switch T5 is connected to the sensing line, a second end of the first switch T5 is connected to the reference voltage line, and a control end of the first switch T5 is connected to the sensing control line. Wherein, the reference voltage line is configured to transmit the reference signal Vref. The sensing control line is configured to transmit the sensing control signal SEN-PRE.
The pixel circuit may further include a second switch T4. A first end of the second switch T4 is connected to the sensing line, a second end of the second switch T4 is connected to the input end of the analog-to-digital converter ADC, and the control end of the second switch T4 is connected to the sampling control line. The sampling control line is configured to transmit the sampling control signal SAMP.
Wherein, when the first switch T5 and the sensing transistor T3 are in a conductive state at the same time, the reference signal Vref can reset the source potential of the driving transistor T1. When the second switch T4 and the sensing transistor T3 are in the conductive state at the same time, the analog-to-digital converter ADC can output the obtained source potential of the driving transistor T1 to the data driver, and then the data driver can provide the corresponding data signal (data) to data wire.
Wherein, the light-emitting device can be an organic light-emitting diode, a quantum dot light-emitting diode, a mini light-emitting diode or a micro-light emitting diode.
In order to alleviate the brightness shift caused by the voltage transmission loss of the data signal data, the related technology uses the relationship curve between the voltage transmission loss ratio (Efficiency) and the voltage of the data signal data as shown in
In view of the technical problem mentioned above that storage resources are excessively occupied due to large amounts of compensation data, this embodiment provides a compensation method for a pixel circuit, as shown in
It can be understood that the compensation method and display panel provided by this embodiment obtain the nonlinear function of the pixel circuit first, then convert the nonlinear function into the corresponding linear function, and then obtain compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference. Since the nonlinear function requires more compensation data and has a larger error than the linear function, therefore, using the converted linear function for compensation can reduce the required storage resources and improve accuracy of compensation.
Wherein, the nonlinear function is the relationship curve between the voltage transmission loss ratio and the voltage of the data signal. The voltage transmission loss ratio is a ratio of the second gate-source voltage difference of the driving transistor in the pixel circuit in the light-emitting stage to the first gate-source voltage difference of the driving transistor in the writing stage.
As shown in
It should be noted that the above-mentioned nonlinear function is shown in
In one embodiment, the step of converting the nonlinear function into the corresponding linear function which is a relationship curve between the first gate-source voltage difference and the second gate-source voltage difference comprisings: setting the voltage transmission loss ratio, the first gate-source voltage difference and the second gate-source voltage difference are Efficiency, Vgs@write and Vgs@emission respectively, the nonlinear function is converted into the following intermediate relationship:
It should be noted that the steps of converting the nonlinear function into the corresponding linear function are specifically as follows: converting the nonlinear function in
Specifically, the voltage (i.e., Vdata) of the data signal (data) is known. That is to say, the gate potential of the driving transistor during the writing phase is Vdata. During the writing phase, the source potential (i.e., Vs) of the driving transistor T1 is the potential (Vref) of reference signal (Vref).
Therefore, it can be obtained that the first gate-source voltage difference (Vgs@write) is Vdata-Vref. The voltage transmission loss ratio (Efficiency) can be determined in advance through relevant technologies or experimental methods. Based on the above intermediate relationship, the second value in the light-emitting stage can be obtained. The gate-source voltage difference is Vgs@emission, and then the above-mentioned intermediate relationship can be obtained based on some point values of Vgs@write and Vgs@emission.
In one embodiment, the step of converting the nonlinear function into the corresponding linear function which is a relationship curve between the first gate-source voltage difference and the second gate-source voltage difference further comprises: converting the intermediate relationship equation into linear function as follows:
It should be noted that by obtaining some corresponding point values from the curve of the above-mentioned intermediate relationship, a linear function as shown in
In one embodiment, the step of obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference comprises: storing k, b; obtaining the compensated first gate-source voltage difference in the low grayscale ranges according to k1, b1, the redetermined second gate-source voltage difference and the first linear function.
It should be noted that each pixel circuit corresponds to a set of k and b. That is to say, during the compensation process, only a set of k and b for each pixel circuit needs to be stored to achieve the voltage transmission loss of the data signal data. Compared with storing fixed parameters in nonlinear functions, this number is smaller, so corresponding storage resources can be saved.
After the step of obtaining the compensated first gate-source voltage difference, since the source potential (i.e., Vs) of the driving transistor T1 remains unchanged during the writing stage, therefore the voltage of the compensated data signal can be determined according to the compensated first gate-source voltage difference, and then the pixel circuit is charged according to the voltage of the compensated data signal. In this way, the light-emitting device can display the desired brightness during the light-emitting stage, and is also beneficial to reducing the brightness difference between different pixel circuits.
In one embodiment, the step of converting the nonlinear function into the corresponding linear function which is a relationship curve between the first gate-source voltage difference and the second gate-source voltage difference comprises steps of: dividing the data signal into multiple grayscale ranges according to a voltage magnitude of the data signal; converting the nonlinear function into the multiple linear functions in different grayscale ranges.
It should be noted that during the fitting process of the above linear function, since the curve shown in
In one embodiment, as shown in
It should be noted that, for the Vgs@emission-Vgs@write linear equation shown in
Wherein, the step of dividing value between low gray level and high gray level can be determined by comparing the deviation trend between the fitting value and the actual value.
In one embodiment, the step of converting the nonlinear function into the first linear function in the low grayscale range H1 and the second linear function in the high grayscale range H2 comprises steps of: determining the first linear function as Vgs@emission=k1*Vgs@write+b1, where k1 and b1 are both constants; determining the second linear function as Vgs@emission=k2*Vgs@write+b2, where k2 and b2 are both constants.
In one embodiment, the step of obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference comprises steps of: obtaining the compensated first gate-source voltage difference in the low grayscale range H1 according to k1, b1, the redetermined second gate-source voltage difference and the first linear function; obtaining the compensated first gate-source voltage difference in the high grayscale range H2 according to k2, b2, the redetermined second gate-source voltage difference and the second linear function.
It should be noted that the specific process of this embodiment can be carried out with reference to the detailed process shown in
In one embodiment, this embodiment provides a display panel that performs the compensation method in at least one of the above embodiments.
It can be understood that, since the display panel provided by this embodiment implements the compensation method in at least one of the above embodiments, it can also be obtained by obtaining the nonlinear function of the pixel circuit firstly, and then converting the nonlinear function into the corresponding linear function, and then obtaining the compensated first gate-source voltage difference according to the linear function and the second gate-source voltage difference. Since nonlinear functions require more compensation data and have larger errors than linear functions, using converted linear functions for compensation can reduce the required storage resources and improve the accuracy of compensation.
In the above embodiments, each embodiment is described with its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.
The compensation method of the pixel circuit and the display panel provided by the embodiments of the present application have been introduced in detail. To sum up, although the present disclosure has been disclosed as above with the preferred embodiment, the above preferred embodiment is not configured to limit the present disclosure, and those skilled in the art can make various changes and embellishments without departing from the spirit and scope of the present disclosure, so the scope of protection of the present disclosure is subject to the scope defined by the claims.
Number | Date | Country | Kind |
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202310545136.X | May 2023 | CN | national |