Method for driving display panel, driving chip and display device

A method for driving a display panel, a driving chip and a display device are provided to ameliorate image retention and improve the display performance. The method includes: monitoring a static pattern in a first display image and defining an area where the static pattern is located as a first area when a display brightness value of the area and a display brightness value of an area where a background pattern thereof is located satisfy a first preset condition; and controlling the static pattern to move during displaying of the first display image, or adjusting grayscale values of sub-pixels in a second area during displaying of a second display image, to which the first display image jumps, the second area being an area, corresponding to the first area in the second display image and having a display brightness value lower than a display brightness value of the first area.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Chinese Patent Application No. 201811404215.4, filed on Nov. 23, 2018, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of display technologies, and in particular, to a method for driving a display panel, a driving chip and a display device.

BACKGROUND

With the development of display technologies, an organic light-emitting diode (OLED) display panel has been more and more widely used due to its excellent characteristics such as self-illumination, high brightness, wide visual angle and fast response.

A pixel circuit of the OLED display panel includes a driving transistor and a plurality of switch transistors. For the existing pixel circuit, a threshold voltage shift of the driving transistor can be caused by manufacturing factors and aging of the transistor, although the uneven display problem resulted from the threshold voltage shift can be ameliorated by internal compensation, hysteresis effect of the driving transistor may cause image retention when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value, which then influences the display performance.

SUMMARY

In view of this, the present disclosure provides a method for driving a display panel, a driving chip and a display device, so as to effectively ameliorate image retention and improve the display performance.

In an aspect, the present disclosure provides a method for driving a display panel, including: monitoring a static pattern in a first display image, and defining an area where the static pattern is located as a first area when a display brightness value of the area and a display brightness value of an area where a background pattern of the static pattern is located satisfy a first preset condition; and controlling the static pattern to move during displaying of the first display image; or adjusting grayscale values of sub-pixels in a second area during displaying of a second display image after the first display image jumps to the second display image, wherein the second area is an area, corresponding to the first area in the second display image and has a display brightness value lower than a display brightness value of the first area.

In another aspect, the present disclosure provides a driving chip, including: a first area positioning module configured to monitor a static pattern in a first display image, and to define an area where the static pattern is located as a first area when a display brightness value of the area and a display brightness value of an area where a background pattern of the static pattern is located satisfy a first preset condition; and a driving module electrically connected to the first area positioning module, and configured to control the static pattern to move during displaying of the first display image, or to adjust grayscale values of sub-pixels in a second area during displaying of a second display image after the first display image jumps to the second display image, wherein the second area is an area, corresponding to the first area in the second display image and has a display brightness value lower than a display brightness value of the first area.

In still another aspect, the present disclosure provides a display device including a display panel; and the driving chip described above. The driving chip is electrically connected to the display panel.

DESCRIPTION OF EMBODIMENTS

For better illustrating technical solutions of the present disclosure, embodiments of the present disclosure will be described in detail as follows with reference to the accompanying drawings.

It should be noted that, the described embodiments are merely part of the embodiments of the present disclosure, but not all of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art without creative efforts according to those described embodiments of the present disclosure are within the scope of the present disclosure.

The terms used in the embodiments of the present disclosure are merely for the purpose of describing particular embodiments but not intended to limit the present disclosure. Unless otherwise noted in the context, objects defined by the singular form expressions “a”, “an”, “the” and “said” used in the embodiments and appended claims of the present disclosure are also intended to include plural form expressions thereof

It should be understood that the term “and/or” used herein is merely an association relationship describing associated objects, indicating that there may be three relationships, for example, A and/or B may indicate three cases, i.e., only A exists, both A and B exists, and only B exists. In addition, the character “/” herein generally indicates that the related objects before and after the character have an “or” relationship.

It should be understood that although the display image may be described using the terms “first”, “second”, etc., in the embodiments of the present disclosure, the display image will not be limited to these terms. These terms are merely used to distinguish display images from one another. For example, without departing from the scope of the embodiments of the present disclosure, a first display image may also be referred to as a second display image, similarly, a second display image may also be referred to as a first display image.

Embodiments of the present disclosure provide a method for driving a display panel.FIG. 1is a schematic diagram of a first display image and a second display image according to an embodiment of the present disclosure, andFIG. 2is a flowchart of a method for driving a display panel according to an embodiment of the present disclosure. The method includes following steps.

Step S1: a static pattern in the first display image1is monitored, and an area where the static pattern1is located is defined as a first area2when a display brightness of the area where the static pattern is located and a display brightness of an area where a background pattern of the static pattern is located satisfy a first preset condition.

In the first display image1, the display brightness of the area where the static pattern is located is relatively high and the display brightness of the area where the background pattern is located is relatively low. For example, with further reference toFIG. 1, the static pattern in the first display image1refers to a pattern “2” having a relatively high brightness in the image, and the background pattern refers to a pattern having a relatively low brightness around the periphery of the pattern “2”.

Step S2: the static pattern is controlled to move during displaying of the first display image1; or, grayscale values of the sub-pixels located in a second area4are adjusted during displaying of the second display image3after the first display image1jumps to the second display image3, herein the second area4is an area, corresponding to the first area2, in the second display image3and has a display brightness lower than the display brightness of the first area2.

After the first display image1jumps to the second display image3, an area, located at the same position as the first area2, in the second display image3is defined as a second area4when this area has a display brightness lower than the previous display brightness of the first area2. For example, again referring toFIG. 1, a part of the area displaying a pattern “8” in the second display image3is the second area4.

During displaying of the first display image1, since the display brightness of the area where the static pattern is located is relatively high, the driving transistor of the sub-pixel located in the first area2will keep receiving a fixed bias voltage for a long time if the location of the static pattern stays unchanged. As a result, after the image jumps, the display brightness of the second area4is relatively low, and the driving transistor in the second area4cannot be quickly switched to a next bias voltage. In this case, significant delay occurs, which leads to retention of the static pattern in the second area4before the image jumps, that is, the image retention occurs. However, in the method for driving the display panel according to this embodiment of the present disclosure, during displaying of the first display image1, the bias voltage received by the driving transistor in the first area2can be constantly switched between a positive bias voltage and a negative bias voltage by controlling location of the static pattern to control movement thereof. In this way, it can be avoided that a certain bias voltage is kept received for a long time. Therefore, when the image jumps, the driving transistor in the first area2can be quickly switched to the next bias voltage, so that the display brightness of the second area4can approximate to desired standard display brightness. In this way, retention of the static pattern in the second area4can be avoided, thereby effectively ameliorating the image retention.

Alternatively, after the first display image1jumps to the second display image3, the display brightness of the second area4is lower than the display brightness of the first area2during displaying of the second display image3; and by adjusting grayscale values of the sub-pixels located in the second area4, for example, by increasing grayscale values of some sub-pixels and thus increasing the brightness of these sub-pixels, a brightness difference between these sub-pixels in the first display image1and these sub-pixels in the second display image3can be reduced. In this way, when the area where these sub-pixels are located is switched between an image having high grayscale value and an image having low grayscale value, the resulted image retention can be effectively ameliorated.

It can be seen that, with the method for driving the display panel according to this embodiment of the present disclosure, the image retention occurring when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value can be effectively ameliorated by controlling the static pattern in the first area2to move, or by adjusting the grayscale values of the sub-pixels in the second area4. Therefore, the display performance can be improved.

In an embodiment, the display brightness value of the area where the static pattern is located is L1, the display brightness value of the area where the background pattern is located is L2, and the first preset condition is that L1/L2>2000.

It should be understood that the display brightness values of different areas in one display image are different, that is, for two adjacent areas, the display brightness of one area of the two adjacent areas is generally larger than the display brightness of the other area of the two adjacent areas. By using the first preset condition to define the ratio of L1 to L2, the area where the static pattern is located will be identified as the first area2only when L1/L2 is larger than or equal to 2000. In this way, identification errors can be avoided.

FIG. 3is a schematic diagram of movement of a static pattern according to an embodiment of the present disclosure. Referring toFIG. 3, a process of controlling the static pattern to move includes: controlling the static pattern to move through M1sub-pixels along a direction x, herein 2≤M1≤16.

It should be noted that the direction x may refer to any direction, that is, the static pattern can move through M1sub-pixels along any direction.

By controlling the static pattern to move through 2 to 16 sub-pixels, on the one hand, it can be avoided that the driving transistor of the sub-pixel located in the first area2keeps receiving a fixed bias voltage for a long time, thereby reducing the delay when switching the image, and on the other hand, it can ensure that the static pattern moves only around the periphery of the first area2, thereby reducing the visibility of the movement of the static pattern to the human eyes, and thus improving the display effect.

In order to further shorten the time for the driving transistor of the first area2to maintain at a certain fixed bias voltage and further reduce the delay, in an embodiment, the movement of the static pattern is controlled to last for a time period of N1, where 2s≤N1≤10s. That is, during displaying of the first display image1, the image is controlled to jump to the second display image3after controlling the static pattern to move for a time period of N1.

During this period of time, the static pattern at an original position can move back and forth along the direction x. For example, the static pattern moves downward from the original position by a distance of M1sub-pixels, then moves upward back to the original position, and then moves upward further by a distance of M1sub-pixels . . . , et cetera.

FIG. 4is a schematic diagram showing a second area in which grayscale values of sub-pixels have been adjusted according to an embodiment of the present disclosure. Referring toFIG. 4, the process of adjusting grayscale values of sub-pixels in the second area4includes: adjusting grayscale values of Kg1green sub-pixels5in the second area4, so that the grayscale values of Kg2green sub-pixels5are each Gg, and the grayscale values of (Kg1-Kg2) green sub-pixels5are each 0 (for easy distinguishing, inFIG. 4, the green sub-pixel5having the grayscale value of Ggis denoted by reference number51, and the green sub-pixel5having the grayscale value of 0 is denoted by reference number52). A standard grayscale value of the green sub-pixel5in the second area4when the second display image3is normally displayed is Ggn, and Gg>Ggn.

For example, during displaying of the second display image3, 100 green sub-pixels5are arranged in the second area4and the corresponding standard grayscale value is 50. Among the 100 green sub-pixels5, the grayscale values of 20 green sub-pixels5are each adjusted to 94, and the grayscale values of the remaining 80 green sub-pixels5are each adjusted to 0.

It should be noted that, the specific numerical values of Kg2and Gg, and the specific arrangement manner of the Kg2green sub-pixels5having a grayscale value of Ggand the (Kg1-Kg2) green sub-pixels5having a grayscale value of 0 are not limited in the embodiments of the present disclosure, and can be set according to actual needs.

After the grayscale values of the green sub-pixels5in the second area4are adjusted, for the Kg2green sub-pixels5whose grayscale values are increased to Gg, increasing the grayscale values of these green sub-pixels5increases the luminous brightness thereof, thereby reducing a difference between a brightness of an area where these green sub-pixels are located in the first display image1and a brightness of the area in the second display image3, and thus effectively ameliorating the image retention occurring in the area after the image jumps; for the (Kg1-Kg2) green sub-pixels5whose grayscale values are reduced to 0, an area where these green sub-pixels5are located are in a black state, and therefore the image retention will not occur in this area when the image jumps. It can be seen that by adjusting the grayscale values of the green sub-pixels5in the second area4, the image retention of the area where the green sub-pixels5are located in the second area4can be effectively ameliorated.

In addition, by adjusting the grayscale values of some green sub-pixels5to be higher than the standard grayscale value Ggnand adjusting the grayscale values of the remaining green sub-pixel5to be 0, a difference between a total brightness of all the green sub-pixels5in the second area4and a desired standard total brightness, thereby improving the display effect.

In addition, it should be noted that, compared with a red image and a blue image, a green image has the most serious image retention when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value. Therefore, by adjusting the grayscale values of the green sub-pixels5in the second area4, the image retention in the second area4can be ameliorated to a greater extent.

Further, the (Kg1-Kg2) green sub-pixels5whose grayscale values are adjusted to 0 are in a black state and the luminous brightness thereof is 0, therefore, in order to ensure that the total brightness of all the green sub-pixels5in the second area4after the grayscale value adjustment is the same as the desired standard total brightness so as to improve the display effect, the Kg2and Ggcan be set such that the total brightness value of the Kg2green sub-pixels5having a grayscale value of Ggis equal to the total brightness value of the Kg1green sub-pixels5having a grayscale value of Ggn.

FIG. 5is another schematic diagram showing a second area in which grayscale values of sub-pixels have been adjusted according to an embodiment of the present disclosure. Referring toFIG. 5, adjusting the grayscale values of the sub-pixels in the second area4may further include: adjusting grayscale values of Kr1red sub-pixels6in the second area4, so that grayscale values of Kr2red sub-pixels6are each Gr, and grayscale values of (Kr1-Kr2) red sub-pixels6are each 0 (for easy distinguishing, inFIG. 5, the red sub-pixel6having the grayscale value of Gris denoted by reference number61, and the red sub-pixel6having the grayscale value of 0 is denoted by reference number62), where Gr>Grn, and Grnis a standard grayscale value of the red sub-pixel6in the second area4when the second display image3is normally displayed; and/or, adjusting grayscale values of Kb1blue sub-pixels7in the second area4, so that grayscale values of Kb2blue sub-pixels7are each Gb, and grayscale values of (Kb1-Kb2) blue sub-pixels7are each 0 (for easy distinguishing, inFIG. 5, the blue sub-pixel7having the grayscale value of Gbis denoted by reference number71, and the blue sub-pixel7having the grayscale value of 0 is denoted by reference number72), where Gb>Gbn, and Gbnis a standard grayscale value of the blue sub-pixel7in the second area4when the second display image3is normally displayed.

Similar to the green sub-pixels5, the image retention in the area where the red sub-pixels6are located in the second area4can be effectively ameliorated by adjusting the grayscale values of the red sub-pixels6in the second area4, and the image retention in the area where the blue sub-pixels7are located in the second area4can be effectively ameliorated by adjusting the grayscale values of the blue sub-pixels6in the second area4. A detailed illustration can refer to the illustration of the green sub-pixels5, and are not further described herein.

Further, in order to ensure that a total luminous brightness of all the red sub-pixels6in the second area4after the grayscale value adjustment is the same as a desired standard total luminous brightness, the Kr2and Grcan be set such that a total brightness value of the Kr2red sub-pixels6having a grayscale value of Gris equal to a total brightness value of the Kr1red sub-pixels6having a grayscale value of Grn. Similarly, in order to ensure that a total luminous brightness of all the blue sub-pixels7in the second area4after the grayscale value adjustment is the same as a desired standard total luminous brightness, the Kb2and Gbcan be set such that a total brightness value of the Kb2blue sub-pixels7having a grayscale value of Gbis equal to a total brightness value of the Kb1blue sub-pixels7having a grayscale value of Gbn.

In an embodiment, in order to further effectively ameliorate the image retention, adjusting the grayscale values of the sub-pixels lasts for a time period of N2, where 2s≤N2≤10s. That is, during displaying of the second display image3, the image is controlled to jump to a subsequent image after adjusting the grayscale values of the sub-pixels lasts for a time period of N2.

In addition, after adjusting the grayscale values of the sub-pixels, the method for driving the display panel may further include: controlling the pattern displayed in the second area4to move, thereby avoiding that the sub-pixels in the second area4keep emitting light for a long time, thereby improving the service life.

Further, in order to ensure that the pattern only moves around the periphery of the second area4so as to reduce the visibility of the movement of the pattern to the human eye, a process of controlling the pattern displayed in the second area4to move may include: controlling the pattern displayed in the second area4to move through M2sub-pixels along a direction x, where 2≤M2≤16.

An embodiment of the present disclosure further provides a driving chip.FIG. 6is a schematic structural diagram of a driving chip according to an embodiment of the present disclosure. Referring toFIG. 6in combination withFIG. 1, the driving chip includes a first area positioning module11and a driving module12. The first area positioning module11is configured to monitor a static pattern in a first display image1. When a display brightness value of an area where the static pattern is located and a display brightness value of an area where a background pattern of the static pattern is located satisfy a first preset condition, the area where the static pattern is located is defined as a first area2. The driving module12is electrically connected to the first area positioning module11and is configured to control the static pattern to move during displaying of the first display image1, or to adjust the grayscale values of the sub-pixels in a second area4during displaying of a second display image after the first display image1jumps to the second display image, the second area4being an area, corresponding to the first area2in the second display image3and having a display brightness lower than the display brightness of the first area2.

With the driving chip according to this embodiment of the present disclosure, during displaying of the first display image1, the bias voltage received by the driving transistor in the first area2can be constantly switched between a positive bias voltage and a negative bias voltage by controlling, by the driving module12, the static pattern to move. In this way, it can be avoided that a certain bias voltage is kept received for an excessively long time. Therefore, when the image jumps, the driving transistor in the first area2can be quickly switched to a next bias voltage, so that the display brightness of the second area4can approximate to desired standard display brightness. In this way, retention of the static pattern in the second area4can be avoided, thereby effectively ameliorating the image retention. Alternatively, after the first display image1jumps to the second display image3, grayscale values of the sub-pixels in the second area4are adjusted through the driving module12, for example, grayscale values of some sub-pixels are increased and thus the brightness of these sub-pixels are increased, then a luminous brightness difference between these sub-pixel in the first display image1and these sub-pixel in the second display image3can be reduced. In this way, when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value, image retention of an area where these sub-pixels are located can be effectively ameliorated. It can be seen that, with the driving chip according to this embodiment of the present disclosure, the image retention occuring when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value can be effectively ameliorated. Therefore, the display performance can be improved.

FIG. 7is another schematic structural diagram of a driving chip according to an embodiment of the present disclosure. Referring toFIG. 7in combination withFIG. 3, when the driving module is configured to control the static pattern to move during displaying of the first display image1, the driving module12may include a first movement control unit121. The first movement control unit121is electrically connected to the first area positioning module11and is configured to control the static pattern to move through M1sub-pixels along the direction x, where 2≤M1≤16.

The static pattern is controlled by the first movement control unit121to move through 2 to 16 sub-pixels. On the one hand, it can be avoided that the driving transistor of the sub-pixel in the first area2keeps receiving a fixed bias voltage for a long time, thereby reducing the delay when the image jumps, and on the other hand, it can ensure that the static pattern moves only around the periphery of the first area2, thereby reducing the visibility of the movement of the static pattern to the human eyes, and thus improving the display effect.

In order to further shorten the time for the driving transistor of the first area2to maintain at a certain fixed bias voltage and further reduce the delay, again referring toFIG. 7, the driving module may further include a moving time control unit122. The moving time control unit122is electrically connected to the first movement control unit to drive the first movement control unit, so that the first movement control unit can control the movement of the static pattern to last for a time period of N1, where 2s≤N1≤10s.

FIG. 8is still another schematic structural diagram of a driving chip according to an embodiment of the present disclosure. Referring toFIG. 8in combination withFIG. 4, when the driving module12is configured to adjust the grayscale values of the sub-pixels in the second area4during displaying of the second display image3, the driving module12may include a second area positioning unit123and a green sub-pixel grayscale adjusting unit124.

The second area positioning unit123is electrically connected to the first area positioning module11, and is configured to define an area, corresponding to the first area2, in the second display image3and having a display brightness value lower than the display brightness value of the first area2as a second area4during displaying of the second display image3. The green sub-pixel grayscale adjusting unit124is electrically connected to the second area positioning unit123and is configured to adjust grayscale values of Kg1green sub-pixels5in the second area4, so that grayscale values of Kg2green sub-pixels5are each Gg, and grayscale values of (Kg1-Kg2) green sub-pixels5are each 0, where Gg>Ggn, Ggnis a standard grayscale value of the green sub-pixels5in the second area4when the second display image3is normally displayed, and the Kg2and Ggsatisfy that a total brightness value of the Kg2green sub-pixels5having a grayscale value of Ggis equal to a total brightness value of the Kg1green sub-pixels5having a grayscale value of Ggn.

The grayscale values of the Kg1green sub-pixels5in the second area4are adjusted by the green sub-pixel grayscale adjusting unit124. For the Kg2green sub-pixels5whose grayscale values are increased to Gg, increasing the grayscale values of these green sub-pixels5can increase the luminous brightness thereof, thereby reducing a brightness difference of an area where these green sub-pixels5are located between the first display image1and the second display image3, and thus effectively ameliorating the image retention occurring in this area after the image jumps; for the (Kg1-Kg2) green sub-pixels5whose grayscale values are reduced to 0, the area where these green sub-pixels5are located are in a black state, and therefore the image retention will not occur in this area when the image jumps. It can be seen that by adjusting the grayscale values of the green sub-pixels5in the second area4, the image retention in the area where the green sub-pixels5are located in the second area4can be effectively ameliorated.

Further, again referring toFIG. 8, the driving module12may further include a red sub-pixel grayscale adjusting unit125and/or a blue sub-pixel grayscale adjusting unit126.

The red sub-pixel grayscale adjusting unit125is electrically connected to the second area positioning unit123and is configured to adjust grayscale values of Kr1red sub-pixels6in the second area4, so that grayscale values of Kr2red sub-pixels6are each Gr, and grayscale values of (Kr1-Kr2) red sub-pixels6are each 0, where Gr>Grn, Grnis a standard grayscale value of the red sub-pixels6in the second area4when the second display image3is normally displayed, and the Kr2and Grsatisfy that a total brightness value of the Kr2red sub-pixels6having a grayscale value of Gris equal to a total brightness value of the Kr1red sub-pixels6having a grayscale value of Grn.

The blue sub-pixel grayscale adjusting unit126is electrically connected to the second area positioning unit123and is configured to adjust grayscale values of Kb1blue sub-pixels7in the second area4, so that grayscale values of Kb2blue sub-pixels7are each Gb, and grayscale values of (Kb1-Kb2) blue sub-pixels7are each 0, where Gb>Gbn, Gbnis a standard grayscale value of the blue sub-pixels7in the second area4when the second display image3is normally displayed, and the Kb2and Gbsatisfy that a total brightness value of the Kb2blue sub-pixels7having a grayscale value of Gbis equal to a total brightness value of the Kb1blue sub-pixels7having a grayscale value of Gbn.

Similar to the green sub-pixels5, the image retention in the area where the red sub-pixels6are located in the second area4can be effectively ameliorated by adjusting the grayscale values of the red sub-pixels6in the second area4, and the image retention in the area where the blue sub-pixels7are located in the second area4can be effectively ameliorated by adjusting the grayscale values of the blue sub-pixels6in the second area4.

FIG. 9is yet another schematic structural diagram of a driving chip according to an embodiment of the present disclosure. In order to further effectively ameliorate the image retention, as shown inFIG. 9, the driving module12may further include an adjusting time control unit127. The adjusting time control unit127is electrically connected to the green sub-pixel grayscale adjusting unit124to drive the green sub-pixel grayscale adjusting unit124, so that the green sub-pixel grayscale adjusting unit124can keep adjusting grayscale values of the green sub-pixels for a time period of N2, where 2s≤N2≤10s.

Further, in order to ensure that the pattern moves only around the periphery of the second area4and reduce the visibility of movement of the pattern to the human eyes, again referring toFIG. 9, the driving module12may further include a second movement control unit128. The second movement control unit128is electrically connected to the second area positioning unit123and is configured to control the pattern displayed in the second area4to move through M2sub-pixels along the direction x, where 2≤M2≤16.

Embodiments of the present disclosure further provide a display device.FIG. 10is a schematic structural diagram of a display device according to an embodiment of the present disclosure. As shown inFIG. 10, the display device includes a display panel100and the above-mentioned driving chip200, and the driving chip200is electrically connected to the display panel100. The structure of the driving chip200has been described in detail in the above embodiments, and will not be further described herein. It should be noted that, the display device shown inFIG. 10is merely illustrative, and the display device may be any electronic device having a display function, such as a cellphone, a tablet computer, a notebook computer, an e-book, or a television.

The display device provided by the embodiments of the present disclosure includes the driving chip200described above. Therefore, with this display device, the image retention occurring when the display panel is switched between an image having a high grayscale value and an image having a low grayscale value can be effectively ameliorated by controlling the static pattern in the first area2to move, or by adjusting the grayscale values of the sub-pixel in the second area4. Therefore, the display performance can be improved

The above-described embodiments are merely illustrative and are not intended to limit the present disclosure. Any modifications, equivalent substitutions and improvements made within the principle of the present disclosure shall fall into the protection scope of the present disclosure.