Patent Application
20240054968
The disclosure relates to an electronic device, and more particularly, to a display driving device and a display control device and an operation method thereof.
Display panels such as liquid crystal display (LCD) panels have been widely used in current display devices. Inevitably, there is a leakage phenomenon in each pixel circuit of the display panel. The smaller the frame rate, the greater the leakage power of the pixel circuit. In the case where the time lengths of each frame are the same, that is, when the frame rate is fixed, for a certain same pixel circuit, its leakage power in different frame periods is approximately the same, so the leakage phenomenon of the pixel circuit is not significant enough to cause flicker or color cast (or a slight flicker or color cast caused by the leakage phenomenon may be tolerable).
When the display panel operates in a variable refresh rate (VRR) mode, the time lengths of each frame may vary from each other. In the case where the time lengths of each frame are different from each other, that is, when the frame rate changes dynamically, because the leakage power of the same pixel circuit in different frame periods is different from each other, the leakage phenomenon causes intolerable flicker or color cast, which affects the picture quality of the display panel. How to improve the flicker or color cast caused by the leakage phenomenon of the pixel circuit is one of the many technical issues in the technical field.
The disclosure provides a display driving device and a display control device and an operation method thereof. The display control device is configured to control a driving operation of a source driver to drive a display panel, so as to improve the flicker or color cast caused by the leakage phenomenon of a pixel circuit.
In an embodiment of the disclosure, the above-mentioned display control device includes a data analyzing circuit and a data compensation circuit. The data analyzing circuit is configured to perform arithmetic operation on multiple sub-pixel data output by a target driving channel of a source driver in a current frame to obtain a resultant value corresponding to the target driving channel. The data compensation circuit is coupled to the data analyzing circuit to receive the resultant value. The data compensation circuit is configured to determine at least one compensation grayscale value corresponding to the resultant value, the compensation grayscale value is to be displayed by the target driving channel in a vertical blank period of a frame period, and the current frame is displayed in the frame period. The target driving channel of the source driver outputs at least one compensation voltage corresponding to the at least one compensation grayscale value in the vertical blank period of the frame period.
In an embodiment of the disclosure, the above-mentioned operation method includes: arithmetic operation is performed on multiple sub-pixel data output by a target driving channel of a source driver in a current frame by a data analysis circuit of the display control device to obtain a resultant value corresponding to the target driving channel; and at least one compensation grayscale value corresponding to the resultant value is determined by a data compensation circuit of the display control device. The compensation grayscale value is to be displayed by the target driving channel in a vertical blank period of a frame period in which the current frame is displayed. The target driving channel of the source driver outputs at least one compensation voltage corresponding to the at least one compensation grayscale value in the vertical blank period of the frame period.
In an embodiment of the disclosure, the above-mentioned display driving device includes a source driver and a display control device. The display control device is coupled to the source driver for controlling a driving operation of the source driver. The display control device performs arithmetic operation on multiple sub-pixel data output by a target driving channel of the source driver in a current frame to obtain a resultant value corresponding to the target driving channel. The display control device determines at least one compensation grayscale value corresponding to the resultant value. The compensation grayscale value is to be displayed by the target driving channel in a vertical blank period of a frame period in which the current frame is displayed. The target driving channel of the source driver outputs at least one compensation voltage corresponding to the at least one compensation grayscale value in the vertical blank period of the frame period.
Based on the above, the display control device according to the embodiments of the disclosure may perform arithmetic operation on multiple sub-pixel data output by a certain target driving channel in the current frame to determine the compensation grayscale value corresponding to the target driving channel. During a vertical blank period of a frame period in which the current frame is displayed, the target driving channel may output the compensation voltage corresponding to the compensation grayscale value to the display panel, so as to reduce the leakage power of the sub-pixel circuit of the display panel as much as possible. Therefore, the display control device may improve the flicker or color cast caused by the leakage phenomenon of the sub-pixel circuit.
In order to make the aforementioned features and advantages of the disclosure comprehensible, embodiments accompanied with drawings are described in detail as follows.
The term “coupled (or connected)” used in the specification (including the claims) may refer to any direct or indirect means of connection. For example, if that a first device is coupled (or connected) to a second device is described in the specification, the description should be construed that the first device may be directly connected to the second device, or the first device may be indirectly connected to the second device through other devices or some kind of connection means. The terms “first,” “second” and the like mentioned in the specification (including the claims) are used to name the elements or to distinguish different embodiments or scopes and are not intended to limit the upper or lower limit of the number of the elements, nor are the terms intended to limit the order of the elements. In addition, wherever possible, elements/components/steps with the same reference numerals in the drawings and embodiments represent the same or similar parts. Elements/components/steps with the same reference numerals or with the same terminology in different embodiments may refer to relative descriptions of each other.
In the embodiment shown in
In general, the source driver 120 has multiple driving channels. Each of the driving channels is coupled to at least one corresponding data line of the display panel 10. For the convenience of description, one of the driving channels of the source driver 120 (hereinafter referred to as the target driving channel) is used as an example for description below. For the other driving channels of the source driver 120, a reference may be made to the relevant description of the target driving channel and inferences may be drawn accordingly, and thus the description is not repeated here.
The display control device 110 may perform arithmetic operation on multiple sub-pixel data output by a certain target driving channel of the source driver 120 in a current frame to obtain a resultant value corresponding to the target driving channel. For example, it is assumed that the corresponding sub-pixel data output by the target driving channel in the current frame has 2160 sub-pixel data, based on the display panel having 4K resolution (3840*2160 pixels). In some embodiments, the display control device 110 may perform one of an average operation, a median operation, and a root mean square operation on the 2160 sub-pixel data output by the target driving channel in the current frame as the arithmetic operation to obtain an average value, a median, or a root mean square value as the resultant value. Alternatively, the display control device 110 may select the maximum value (or the minimum value) as the resultant value from the 2160 sub-pixel data output by the target driving channel in the current frame.
The display control device 110 may determine at least one compensation grayscale value corresponding to the resultant value. The display control device 110 may output the at least one compensation grayscale value to the source driver 120 during a vertical blank period of a frame period in which the current frame is displayed. The at least one compensation grayscale value is to be displayed by the target driving channel in the vertical blank period during the frame period. The target driving channel of the source driver 120 may output at least one compensation voltage corresponding to the at least one compensation grayscale value to the display panel 10 during the vertical blank period.
According to different design requirements, the implementation manner of the above-mentioned display control device 110 may be hardware, firmware, software, or a combination of more than one of the aforementioned three implementations. In terms of hardware, the display control device 110 may be implemented as a logic circuit on an integrated circuit. The relevant functions of the display control device 110 may be implemented as hardware using hardware description languages (e.g., Verilog HDL or VHDL) or other suitable programming languages. For example, the relevant functions of the display control device 110 may be implemented in one or more controllers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), digital signal processors (DSPs), field programmable gate arrays (FPGAs), and/or various logic blocks, modules, and circuits in other processing units.
In terms of software and/or firmware, the relevant functions of the display control device 110 may be implemented as programming codes. For example, the display control device 110 is implemented using general programming languages (e.g., C, C++, or assembly languages) or other suitable programming languages. The programming code may be recorded/stored in a “non-transitory readable medium”. In some embodiments, the non-transitory readable medium includes, for example, a semiconductor memory, a programmable logic circuit, and/or a storage device. A central processing unit (CPU), a controller, a microcontroller, or a microprocessor may read and execute the programming code from the non-transitory readable medium, so as to implement the relevant functions of the display control device 110.
The data compensation circuit 112 is coupled to the data analyzing circuit 111 to receive the resultant value. In step S320, the data compensation circuit 112 may determine at least one compensation grayscale value corresponding to the resultant value. The at least one compensation grayscale value is to be displayed by the target driving channel of the source driver 120 in a vertical blank period of a frame period in which the current frame is displayed. In step S330, the target driving channel of the source driver 120 outputs at least one compensation voltage corresponding to the at least one compensation grayscale value to the display panel 10 in the vertical blank period of the frame period.
Based on the above, the display control device 110 shown in
In the embodiment shown in
The frame rate detection circuit 113 may provide the detection result, i.e., the frame rate, to the data compensation circuit 115. The data compensation circuit 115 may determine the at least one compensation grayscale value as a single compensation grayscale value or multiple compensation grayscale values according to the frame rate (as the detection result of the frame rate detection circuit 113). When the data compensation circuit 115 outputs the single compensation grayscale value to the source driver 120, the target driving channel of the source driver 120 outputs a grayscale voltage corresponding to the single compensation grayscale value to the display panel 10 during the blank period of the frame period. Alternatively, when the data compensation circuit 115 outputs the compensation grayscale values to the source driver 120, the target driving channel of the source driver 120 outputs multiple compensation grayscale voltages corresponding to the compensation grayscale values to the display panel 10 at different time points in the vertical blank period of the frame period, which may be defined by different numbers of line periods passing from the end of the active data period (or the vertical blank period start time).
Please refer to
Similarly, assuming that the frame period F2 is the current frame, the data analyzing circuit 114 may perform arithmetic operation on multiple sub-pixel data output by a target driving channel of the source driver 120 in the active data period A2 of the frame period F2 to obtain a resultant value corresponding to the target driving channel in the active data period A2. Based on the resultant value corresponding to the active data period A2, the data compensation circuit 115 may determine a compensation grayscale value Gb1 corresponding to the resultant value of the active data period A2, and provide the compensation grayscale value Gb1 to the source driver 120. After the active data period A2 ends, based on the compensation grayscale value Gb1 provided by the data compensation circuit 115, the target driving channel of the source driver 120 may output a compensation voltage corresponding to the compensation grayscale value Gb1 to the display panel 10 during the vertical blank period VB2 of the frame period F2.
The frame rate detection circuit 113 may provide positions of multiple reconfigured time points such as t21-t24 in the vertical blank period VB2 to the data compensation circuit 115. When the time reaches a time point t21 in the vertical blank period VB2, the data compensation circuit 115 may generate a compensation grayscale value Gb2 and provide the compensation grayscale value Gb2 to the source driver 120, so that the target driving channel of the source driver 120 may output a compensation voltage corresponding to the compensation grayscale value Gb2 to the display panel 10 after the time point t21. When the time reaches a time point t22 in the vertical blank period VB2, the data compensation circuit 115 may generate a compensation grayscale value Gb3 and provide the compensation grayscale value Gb3 to the source driver 120, so that the target driving channel of the source driver 120 may output a compensation voltage corresponding to the compensation grayscale value Gb3 to the display panel 10 after the time point t22. When the time reaches a time point t23 in the vertical blank period VB2, the data compensation circuit 115 may generate a compensation grayscale value Gb4 and provide the compensation grayscale value Gb4 to the source driver 120 when the time reaches a time point t23 in the vertical blank period VB2, so that the target driving channel of the source driver 120 may output a compensation voltage corresponding to the compensation grayscale value Gb4 to the display panel 10 after the time point t23. When the time reaches a time point t24 in the vertical blank period VB2, the data compensation circuit 115 may generate a compensation grayscale value Gb5 and provide the compensation grayscale value Gb5 to the source driver 120, so that the target driving channel of the source driver 120 may output a compensation voltage corresponding to the compensation grayscale value Gb5 to the display panel 10 after the time point t24 until the vertical blank period VB2 ends. The longer the vertical blank period in a frame period is, the more compensation steps realized by more compensation grayscale values the display control device may provide.
The embodiment does not limit the manner in which the data compensation circuit 115 generates the compensation grayscale value. For example, in some embodiments, the data compensation circuit 115 may multiply the compensation grayscale value Gb1 by a certain coefficient g to generate the compensation grayscale value Gb2, that is, Gb2=Gb1*g. The coefficient g may be a real number determined according to the actual design. By inference, the compensation grayscale value Gb3 may be the product of the compensation grayscale value Gb2 multiplied by the coefficient g, the compensation grayscale value Gb4 may be the product of the compensation grayscale value Gb3 multiplied by the coefficient g, and the compensation grayscale value Gb5 may be the product of the compensation grayscale value Gb4 multiplied by the coefficient g. In another embodiments, each of the compensation grayscale values Gb2-Gb4 may be the product of the compensation grayscale value Gb1 and a respective coefficient.
In other embodiments, the data compensation circuit 115 may subtract (or add) a certain real number d from (or to) the compensation grayscale value Gb1 to generate the compensation grayscale value Gb2. The real number d may be determined according to the actual design. By inference, the compensation grayscale value Gb3 may be the difference between the compensation grayscale value Gb2 minus the real number d (or the sum of the compensation grayscale value Gb2 plus the real number d), and the compensation grayscale value Gb4 may be the difference between the compensation grayscale value Gb3 minus the real number d (or the sum of the compensation grayscale value Gb3 plus the real number d), and the compensation grayscale value Gb5 may be the difference between the compensation grayscale value Gb4 minus the real number d (or the sum of the compensation grayscale value Gb4 plus the real number d).
In still other embodiments, the data compensation circuit 115 may look up the corresponding difference values from a lookup table according to the position of the preconfigured time points in the vertical blank period. For example, the contents of the lookup table may include different difference values for different time points. These difference values of the lookup table may be multiple real numbers determined according to the actual design. Taking the vertical blank period VB2 as an example, when the current point falls between the time point t21 and the time point t22, the data compensation circuit 115 may obtain a difference value D1 from the lookup table. The data compensation circuit 115 may subtract (or add) the difference value D1 from (or to) the compensation grayscale value Gb1 to generate the compensation grayscale value Gb2. When the current point falls between the time point t22 and the time point t23, the data compensation circuit 115 may obtain a difference value D2 from the lookup table. The compensation grayscale value Gb3 may be the difference between the compensation grayscale value Gb1 minus the difference value D2 (or the sum of the compensation grayscale value Gb1 plus the difference value D2). When the current point falls between the time point t23 and the time point t24, the data compensation circuit 115 may obtain a difference value D3 from the lookup table. The compensation grayscale value Gb4 may be the difference between the compensation grayscale value Gb1 minus the difference value D3 (or the sum of the compensation grayscale value Gb1 plus the difference value D3). When the current point falls between the time point t24 and the time point t25, the data compensation circuit 115 may obtain a difference value D4 from the lookup table. The compensation grayscale value Gb5 may be the difference between the compensation grayscale value Gb1 minus the difference value D4 (or the sum of the compensation grayscale value Gb1 plus the difference value D4).
In some further embodiments, different periods in the vertical blank period may have the same compensation grayscale value. Taking the vertical blank period VB2 as an example, the compensation grayscale values Gb1, Gb2, Gb3, Gb4, and Gb5 may be the same as each other.
In summary, the display control device 110 according to the above-mentioned embodiments may perform arithmetic operation on multiple sub-pixel data output by a certain target driving channel of the source driver 120 in the current frame, so as to determine one (or more) compensation grayscale values corresponding to the target driving channel. During the vertical period of the current frame, the target driving channel of the source driver 120 may output one (or more) compensation voltages corresponding to the compensation grayscale values to the display panel 10, so as to reduce the leakage power of the sub-pixel circuit of the display panel 10 as much as possible. Therefore, the display control device 110 may improve the flicker or color cast caused by the leakage phenomenon of the sub-pixel circuit of the display panel 10.
Although the disclosure has been described with reference to the above embodiments, the described embodiments are not intended to limit the disclosure. People of ordinary skill in the art may make some changes and modifications without departing from the spirit and the scope of the disclosure. Thus, the scope of the disclosure shall be subject to those defined by the attached claims.
