The invention relates to a display apparatus and more particularly to a display panel driving circuit and a method for capturing error information thereof.
Many display apparatuses are equipped with light-emitting diode (LED) display panels, such as organic light-emitting diode (OLED) display panels. After the OLED has been used for a period of time, a phenomenon of decay occurs, and as a result, a relation between a voltage and a current of two terminals of the OLED appears to drift along with time. The phenomenon of decay would cause an issue of uneven panel brightness. In order to compensate the issue of uneven panel brightness caused by the LED decay, a possible compensation method may be electrical compensation. According to the principle of electrical compensation, a given current is supplied from a source driving circuit to an OLED of a pixel circuit, and then a voltage of the OLED is detected by the source driving circuit, or alternatively, the given current is supplied from the source driving circuit to the OLED of a pixel circuit, and then a current of the OLED is detected by the source driving circuit. According to the difference between a reference voltage-current relation between a current voltage-current relation of the OLED, a control circuit (for example, a timing controller) may compensate pixel data.
However, in either the scenario that “the current is supplied to the OLED, and then the voltage of the OLED is detected”, or the scenario that “the voltage is supplied by the OLED, and then the current of the OLED is detected”, a part of the supply or the detection is certainly performed in a form of current. Due to errors in a transistor manufacturing process, a current error that cannot be ignored exists in each source driving circuit. The current-voltage relation of the OLED caused by the current errors of the source driving circuit cannot be accurately obtained. Namely, in the presence of the current errors of the source driving circuit, the electrical compensation cannot be performed accurately on the OLED.
The disclosure provides a display panel driving circuit and a method for capturing error information thereof to obtain driving circuit error information.
According to an embodiment of the invention, a method for capturing driving circuit error information indicating errors caused by a source driving circuit for driving a light-emitting diode (LED) display panel is provided. The method includes: obtaining LED error information indicating errors caused by an LED of a pixel circuit; driving the LED display panel by the source driving circuit to obtain LED and driving circuit error information indicating errors caused by the LED and a sensing current or a driving current of the source driving circuit; and obtaining source driving circuit error information according to the LED error information and the LED and driving circuit error information, wherein the driving circuit error information indicates errors caused by the sensing current or the driving current of the source driving circuit.
According to an embodiment of the invention, a driving circuit for driving a LED display panel is provided. The LED display panel includes at least one pixel circuit, and the pixel circuit includes at least one field-effect transistor and an LED. The pixel circuit is connected to a data line and a sensing line of the LED display panel. The driving circuit includes a timing controller circuit. The timing controller circuit is configured to control a source driving circuit to drive the data line of the LED display panel and sense the sensing line of the LED display panel. In a detection operation period, the timing controller circuit is configured to obtain errors caused by a driving current or a sensing current of the source driving circuit (which is driving circuit error information). The timing controller circuit obtains original LED sensing data from the source driving circuit in the detection operation period. Based on the source driving circuit error information, the timing controller circuit compensates the original LED sensing data to generate LED error information indicating errors caused by the LED of the pixel circuit.
According to an embodiment of the invention, a driving circuit for driving a light-emitting diode (LED) display panel is provided. The LED display panel includes at least one pixel circuit, and the pixel circuit includes at least one field-effect transistor and an LED. The pixel circuit is connected to a data line and a sensing line of the LED display panel. The driving circuit includes a timing controller circuit. The timing controller circuit is configured to control a source driving circuit to drive the data line of the LED display panel and sense the sensing line of the LED display panel. In a normal operation period, the timing controller circuit is configured to obtain first LED error information indicating errors caused by the LED of the pixel circuit. In a detection operation period before the normal operation period, the timing controller circuit generates and stores or updates the first LED error information. The timing controller circuit obtains original pixel data in the normal operation period and compensates the original pixel data by using the first LED error information to generate compensated pixel data. The timing controller circuit provides the compensate pixel data to the source driving circuit in the normal operation period, such that the source driving circuit drives the LED display panel according to the compensated pixel data.
To sum up, the display panel and the method for capturing the error information thereof provided by the embodiments of the invention can obtain the errors caused by the LED of the pixel circuit (which is the LED error information) and obtain the errors caused by the LED and the sensing current (or the driving current) of the driving circuit (which is the LED and driving circuit error information). According to the LED error information and the LED and driving circuit error information, the driving circuit of the display panel can obtain the errors caused by the sensing current (or the driving current) of the driving circuit (which is the driving circuit error information).
To make the above features and advantages of the invention more comprehensible, embodiments accompanied with drawings are described in detail below.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
The term “couple (or connect)” herein (including the claims) are used broadly and encompass direct and indirect connection or coupling means. For example, if the disclosure describes a first apparatus being coupled (or connected) to a second apparatus, then it should be interpreted that the first apparatus can be directly connected to the second apparatus, or the first apparatus can be indirectly connected to the second apparatus through other devices or by a certain coupling means. Moreover, elements/components/steps with same reference numerals represent same or similar parts in the drawings and embodiments. Elements/components/notations with the same reference numerals in different embodiments may be referenced to the related description.
The TCON circuit 101 sends control signals (for example, control signals SDC_1, . . . and SDC_i illustrated in
In the embodiment illustrated in
A first terminal (e.g., a source) of the sensing FET 202 can be coupled to the sensing line 205. A second terminal (e.g., a drain) of the sensing FET 202 can be coupled to the LED 203. A control terminal (e.g., a gate) of the sensing FET 202 is coupled to another scanning line (a gate line, not shown) to receive a control signal VG2. When the sensing FET 202 is turned on, the source driving circuit 207 may sense electrical characteristics (e.g., the driving current I_LED and/or the driving voltage V_LED) of the LED 203.
To be detailed, in step 501, the TCON circuit 101 controls the source driving circuit 207, so as to drive the pixel circuit 200. By driving the pixel circuit 200, the TCON circuit 101 may obtain FET error information. The FET error information indicates errors caused by the at least FET (for example, the FETs 201, 202 and/or 206 illustrated in
For instance, based on the control of the TCON circuit 101, the source driving circuit 207 may control the LED 203 in the pixel circuit 200 not to emit light, namely, control the driving voltage V_LED to be less than a threshold voltage LED 203. In the premise that the LED 203 is controlled not to emit light, the TCON circuit 101 controls the source driving circuit 207 to sense the at least one FET in the pixel circuit 200 so as to obtain the FET error information. For example, the source driving circuit 207 provides a certain test voltage through the data line 204 to drive the pixel circuit 200 and measures a corresponding voltage through the sensing line 205. The test voltage may be determined based on a design requirement. Based on a relation between the test voltage and the corresponding voltage, the TCON circuit 101 may obtain the electrical error information (i.e., the FET error information) of the FETs 201, 202 and 206. In addition, the TCON circuit 101 may turn on the sensing FET 202 and turn off the switching FET 201 to sense the FETs in the pixel circuit 200, so as to obtain the FET error information. The TCON circuit 101 may record the electrical error information (i.e., the FET error information) of the FETs 201, 202 and 206 in an electrical compensation look-up table. The electrical compensation look-up table may be placed in an FET compensation circuit 610 of a timing controller circuit 101 illustrated in
The TCON circuit 101, in step 502, may further compensate the original pixel data by using the FET error information to generate the compensated pixel data. There are at least two factors that can cause the issue of uneven panel brightness, one refers to errors caused by the FETs in the pixel circuit, and the other one refers to the errors caused by the LED in the pixel circuit. After the original test data is compensated by using the FET error information, in step 502, the errors caused by the LED may be captured by using an optical instrument. When the compensation for the FETs by using the FET error information is completed, in step 502, based on the control of the TCON circuit 101, the source driving circuit 207 may drive the pixel circuit 200 by using the compensated test data, so as to control the LED 203 to emit light. Namely, the source driving circuit 207 may provide a compensated test voltage corresponding to the compensated test data through the data line 204 to drive the pixel circuit 200. In this circumstance, the optical instrument (not shown) may measure the LED display panel to generate optical test data of the LED 203. Based on the optical test data, the TCON circuit 101 may obtain the LED error information indicating errors caused by the LED 203. For example, an actual brightness (i.e., an actual grayscale value) of the LED 203 may be measured by the optical instrument. The compensated test data corresponds to an ideal brightness (i.e., an ideal grayscale value). By comparing the actual brightness (i.e., the actual grayscale value) with the ideal brightness (i.e., the ideal grayscale value), the TCON circuit 101 (or a test platform) may calculate optical error information (i.e., the LED error information) of the LED 203 in the pixel circuit 200. Thus, the TCON circuit 101 may control the source driving circuit 207 based on the compensated test data to drive the LED display panel while an optical measurement may be performed to sense the LED to obtain the LED error information.
The LED error information may be stored in an optical compensation look-up table. The optical compensation look-up table may be implemented in an LED compensation circuit 620 of the timing controller circuit illustrated in
In step 503, the LED display panel is driven by the source driving circuit 207 to obtain “LED and driving circuit error information”. The LED and driving circuit error information may indicate errors caused by the LED 203 and the sensing current (or the driving current) of the source driving circuit 207. For instance, the TCON circuit 101 may control the source driving circuit 207 to drive the LED display panel and turn on all the FETs (e.g., the sensing FET 202) of the LED display panel. The source driving circuit 207 provides the driving current I_LED to drive the LED 203 through the sensing line 205. In this circumstance, the optical measurement may be performed to sense the brightness (i.e., the grayscale) of the LED 203 in step 503, so as to obtain the LED and driving circuit error information. For instance, the optical instrument (not shown) may, in step 503, measure the LED display panel to generate optical data. Based on the optical data, the TCON circuit 101 (or the test platform) may obtain the LED and driving circuit error information. The LED and driving circuit error information may be stored in a look-up table. The look-up table may be placed in a look-up table 640 of the TCON circuit 101 illustrated in
In other embodiments, the TCON circuit 101, in step 503, may control the source driving circuit 207 to sense the LED 203, so as to obtain the LED and driving circuit error information, wherein all of the FETs in the pixel circuit 200 are turned on. For instance, the source driving circuit 207 may, in step 503, provide a voltage to the data line 204 to drive the LED 203. Then, the source driving circuit 207 may measure the sensing current through the sensing line 205 and converts the sensing current into the optical data. Based on the optical data, the TCON circuit 101 may, in step 503, obtain the LED and driving circuit error information.
The TCON circuit 101 may perform step 504 to obtain driving circuit error information indicating errors caused by the sensing current (or the driving current) of the source driving circuit 207. In step 504, the TCON circuit 101 may obtain the driving circuit error information according to the LED and driving circuit error information obtained in step S503 and the LED error information obtained in step S502. For instance, the TCON circuit 101 may remove an LED error component indicted by the LED error information from the LED and driving circuit error information, so as to obtain the driving circuit error information. After obtaining the driving circuit error information, the driving circuit error information may be recorded in the look-up table 640 of the TCON circuit 101 illustrated in
In step 505, the TCON circuit 101 may, by using the driving circuit error information related to the source driving circuit 207 obtained in step 504, compensate the electrical information of the LED 203 in the pixel circuit 200 which is currently detected by the source driving circuit 207. The compensated electrical information may be recorded in the electrical compensation look-up table of an LED compensation circuit 630 of the TCON circuit 101 illustrated in
In a detection operation period, the TCON circuit 101 may obtain the driving circuit error information (step 504) and obtain original LED sensing data SD1 from the source driving circuit 207. In the detection operation period, the TCON circuit 101 may compensate the original LED sensing data SD1 based on the driving circuit error information to generate the LED error information. The LED error information indicates errors caused by the LED 203 of the pixel circuit 200.
In a normal operation period, the TCON circuit 101 may obtain first LED error information. The first LED error information indicates errors caused by the LED 203 of the pixel circuit 200. In the detection operation period before the normal operation period, the TCON circuit 101 may generate and store (or update) the first LED error information. In the normal operation period, the TCON circuit 101 may obtain original pixel data PD1. The TCON circuit 101, in the normal operation period, may compensate the original pixel data PD1 by using the first LED error information to generate compensated pixel data PD2. The TCON circuit 101 may provide the compensate pixel data PD2 to the source driving circuit 207 in the normal operation period, such that the source driving circuit 207 may drive the LED display panel 100 according to the compensated pixel data PD2.
The TCON circuit 101 illustrated in
Before the detection operation period (e.g., in the production line), steps 501 to 504 illustrated in
In the detection operation period, the source driving circuit 207 may detect the current electrical information (e.g., information related to the driving current I_LED and/or a driving voltage V_LED) in the LED 203 in the pixel circuit 200 through the sensing line 205, and then returns the original LED sensing data SD1 containing the electrical information to the adjustment circuit 650 of the TCON circuit 101. The adjustment circuit 650 may refer the look-up table 640 recording the driving circuit error information, so as to capture the driving circuit error information related to the source driving circuit 207 from the look-up table 640. In the detection operation period, the adjustment circuit 650 may compensate the original LED sensing data SD1 based on the driving circuit error information, so as to generate compensated LED sensing data SD2 (i.e., the first LED error information). In the detection operation period, the adjustment circuit 650 of the TCON circuit 101 may update the electrical compensation look-up table in the LED compensation circuit 630, so as to record the compensated LED sensing data SD2 (i.e., the first LED error information) in the electrical compensation look-up table having the original LED error information. After the detection operation period ends, the TCON circuit 101 enters the normal operation mode.
In the normal operation period, the FET compensation circuit 610 may compensate the original pixel data PD1 according to the FET error information obtained in step 501 described above to generate first compensated data. An input terminal of the LED compensation circuit 620 is coupled to an output terminal of the FET compensation circuit 610 to receive the first compensated data. In the normal operation period, the LED compensation circuit 620 may compensate the first compensated data according to the LED error information (i.e., second LED error information) obtained in step 502 described above to generate second compensated data. A compensation algorithm of the FET compensation circuit 610 and the LED compensation circuit 620 is not limited in the present embodiment. For instance, the FET compensation circuit 610 and/or the LED compensation circuit 620 may perform a conventional compensation algorithm or other algorithms.
An input terminal of the LED compensation circuit 630 can be coupled to an output terminal of the LED compensation circuit 620 to receive the second compensated data. In the normal operation period, according to the compensated LED sensing data SD2 (i.e., the first LED error information) recorded in the electrical compensation look-up table in the LED compensation circuit 630, the LED compensation circuit 630 may compensate the second compensated data to generate the compensated pixel data PD2 to the source driving circuit 207. A compensation algorithm of the LED compensation circuit 630 is not limited in the present embodiment. For instance, the LED compensation circuit 630 may perform a conventional compensation algorithm or other algorithms. Thus, based on the LED error information, the LED and driving circuit error information, the FET error information and/or the driving circuit error information, the TCON circuit 101 may compensate the original pixel data PD1 in the normal operation period, so as to generate the compensated pixel data PD2 to the source driving circuit 207.
Based on the above, the display panel driving circuit and the method for capturing error information thereof provided by the embodiments of the invention can obtain the errors caused by the LED of the pixel circuit (which is the LED error information) and obtain the errors caused by LED and the sensing current (or the driving current) of the source driving circuit (which is the LED and driving circuit error information). According to the LED error information and the LED and driving circuit error information, the display panel driving circuit can obtain the errors caused by the sensing current (or the driving current) of the source driving circuit (which is the driving circuit error information). By applying the captured error information to the compensation algorithm of the display panel, the timing controller circuit can solve an issue of display abnormality resulting from the decay of the LED in the LED display panel along with time. Moreover, the capturing method can be built in the existing LED panel manufacturing process without purchasing additionally any equipment, which can reduce difficulty of introduction and provide applicability in mass production.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
This application claims the priority benefit of U.S. provisional application Ser. No. 62/582,955, filed on Nov. 8, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
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