Display device and driving method thereof

Abstract

The invention provides a display device and a driving method of the display device, the display device comprises a time sequence control module and a source electrode driving circuit, and the driving method comprises the following steps: the working time sequence of the source electrode driving circuit comprises a plurality of effective display time periods and a plurality of vertical interval time periods which are arranged at intervals; the vertical interval time period comprises a plurality of rows of invalid display time periods; the time sequence control module controls the pre-charging state of the source electrode driving circuit on the source electrode line according to the gray scale voltage value of the first row of pixels of the display device in the vertical interval time period. According to the invention, the transient impact current in the source line corresponding to the first row of pixels can be greatly reduced, and the EMI problem of the source drive circuit caused by the charging unsaturation problem of the first row of source lines and the overlarge transient current value of the power supply is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of display devices, and particularly to a display device and a driving method thereof. Background Art

[0002] With the development of display technology, the new generation of display screens tend to be large-sized and high-resolution. This type of display screen requires a considerable amount of power consumption to charge its source lines, especially when displaying heavy-load images or when the power supply capacity of the power module is limited. For high-resolution and high-frame-rate display screens, the charging time provided to the source line is short, and this charging time may not allow the source line to reach the target level.

[0003] As Figure 1 shown, it is a schematic diagram of the existing charging situation. The working timing of the display driving circuit in the display device includes an active display period (Active period) and a vertical blanking period (Vertical porch period / V porch period). The existing source line generally starts charging at the beginning of the Active period. Since it takes a certain time for charging to reach saturation, this way of starting charging at the beginning of the Active period often results in unsaturated charging of the source lines S1 / S3 / S5 when the first-row pixels are displayed. As Figure 1 shown, the solid-line rising segments corresponding to S1 / S3 / S5 do not reach saturation throughout the time period of the first row. Moreover, in order to reduce the impact of unsaturated charging of the source line when the first-row pixels are displayed, in the prior art, the source line when the first-row pixels are displayed is usually quickly charged to saturation within a very short time of the first row. However, due to the short time, on the one hand, it cannot ensure charging to saturation; on the other hand, the rapid rise of the voltage of the source line in a short time will also cause too much sudden drop in the power supply voltage of the power module, as shown by the AVDD line in Figure 1 , and at the same time, it will also bring a sudden increase in the transient current, as shown by I_AVDD in Figure 1 . And this abnormal spike in the power supply current will cause interference to the surrounding circuits and bring serious EMI (Electromagnetic Interference) damage to the surrounding circuits. Summary of the Invention

[0004] The object of the present invention is to provide a display device and a driving method thereof to solve the problem of unsaturated charging of the source line when the first-row pixels are displayed, the problem of poor power supply stability caused by too much drop in the power supply voltage value due to the need to quickly charge the source line to saturation when the first-row pixels are displayed, and the EMI problem introduced by too large a transient current value of the power supply.

[0005] To solve the above problems, the present invention is implemented through the following technical solutions:

[0006] A driving method for a display device, the display device includes a timing control module and a source driver circuit, the working timing of the source driver circuit includes a plurality of effective display periods and a plurality of vertical blanking periods arranged at intervals, and the vertical blanking periods include a plurality of row blanking periods. The timing control module controls the source driver circuit to pre-charge the source lines according to the gray-scale voltage value of the first-row pixels of the display device during the vertical blanking periods.

[0007] Optionally, according to the magnitude of the gray-scale voltage value of the first-row pixels, the timing control module adjusts the number of rows of the blanking periods for pre-charging the source driver circuit to turn on during the vertical blanking periods.

[0008] Optionally, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row in advance during the blanking periods during the vertical blanking periods.

[0009] Optionally, the timing control module controls the source driver circuit to charge the source lines of the display device two rows in advance during the blanking periods during the vertical blanking periods.

[0010] Optionally, the timing control module also adjusts the pre-charging time of the source line corresponding to the first-row pixels according to the magnitude of the load capacitance of the source line. If the capacitance value of the load capacitance is large, the pre-charging time is relatively long; if the capacitance value of the load capacitance is small, the pre-charging time is relatively short.

[0011] Optionally, the voltage value of the pre-charging is adjustable.

[0012] Optionally, one vertical blanking period includes: a post-blanking shoulder period and a pre-blanking shoulder period. The post-blanking shoulder period includes a plurality of row blanking periods; the pre-blanking shoulder period includes a plurality of row blanking periods.

[0013] Optionally, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row in advance during the post-blanking shoulder period and then enter the effective display period adjacent to the vertical blanking period.

[0014] Optionally, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row in advance during the pre-blanking shoulder period and then enter the effective display period adjacent to the vertical blanking period.

[0015] Optionally, the grayscale voltage value range is set with the midpoint grayscale voltage value as the boundary, including a first grayscale voltage value range with multiple grayscale voltage values less than the midpoint grayscale voltage value and a second grayscale voltage value range with multiple grayscale voltage values greater than or equal to the midpoint grayscale voltage value.

[0016] Optionally, when the grayscale voltage value of the first row of pixels is in the first grayscale voltage value range, the timing control module controls the source driver circuit to charge the source line of the display device at least one row earlier than the invalid display period during the blanking back porch period of the vertical blanking period and then enter the effective display period adjacent to the vertical blanking period.

[0017] When the saturation grayscale voltage value required by the first row of pixels is in the second grayscale voltage value range, the timing control module controls the source driver circuit to charge the source line of the display device at least one row earlier than the invalid display period during the front porch period of the vertical blanking period and then enter the effective display period adjacent to the vertical blanking period.

[0018] Optionally, the voltage value reached after pre-charging is less than the grayscale voltage of the first row of pixels.

[0019] On the other hand, the present invention also provides a display device, including a source driver circuit and a timing control module, and the source driver circuit and the timing control module apply the driving method as described above to drive the display device to display an image.

[0020] The present invention has at least one of the following technical effects:

[0021] By pre-charging the source line during the vertical blanking period, a pre-charge voltage is obtained, so that the voltage in the source line corresponding to the first row of pixels is charged from the pre-charge voltage and reaches the saturation voltage at the beginning of the effective display period. This can not only solve the problem of unsaturated charging in the source line corresponding to the first row of pixels, improve the image display effect of the display device, but also reduce the decrease in the power supply voltage value, improve the power supply stability, and further improve the image display effect of the display device; it can also greatly reduce the power supply transient current value, solve the EMI problem caused by too large a power supply transient current value, avoid electromagnetic interference to other chips or circuits in the circuit, and enhance the stability of the system operation.

[0022] The present invention sets and adjusts the number of rows of the invalid display period for pre-charging the source driver circuit to be turned on during the vertical blanking period according to the magnitude of the grayscale voltage value of the first row of pixels. Thus, the present invention can balance power consumption by controlling the pre-charging start time, solve the problem of unsaturated charging in the source line corresponding to the first row of pixels, improve the power supply stability, and reduce the power supply transient current value.

[0023] By adjusting the voltage value of pre-charging, the present invention can balance power consumption, solve the problem of insufficient charging in the source line corresponding to the first-row pixels, improve power supply stability, and reduce the power supply transient current value.

[0024] The present invention adjusts the pre-charging start time according to the grayscale voltage value range, thereby better solving the problem of insufficient charging in the source line corresponding to the first-row pixels, improving power supply stability, and reducing the power supply transient current value.

[0025] The source line corresponding to the first-row pixels of the present invention is only turned on when pre-charging is required in advance, which can save power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a charging situation diagram of the source line of the driving method of the existing display device.

[0027] Figure 2 It is a comparison diagram of the charging situation of the source line of the driving method of the display device provided by an embodiment of the present invention and the existing charging situation;

[0028] Figure 3 It is a charging timing diagram of the source line of the driving method of the display device provided by another embodiment of the present invention;

[0029] Figure 4 It is a schematic structural diagram of the display device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following further describes in detail a display device and a driving method of the display device proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and all use non-precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features, and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions of the implementation of the present invention. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0031] Combined Figure 2 and Figure 3 As shown, a driving method of a display device provided in this embodiment is as Figure 4As shown, the display device 10 includes a timing control module 130 and a source driver circuit 110. The operating timing of the source driver circuit includes a plurality of active display periods Active and a plurality of vertical blanking periods V porch arranged at intervals. The vertical blanking period V porch includes a plurality of line blanking periods, such as Figure 2 As shown, the labels BP1 to BPn and FP1 to FPm represent the start of a line blanking period. For example, from the start of BP1 to before the start of the active display period Active is a line blanking period. The timing control module controls the pre-charging state of the source lines of the source driver circuit according to the gray-scale voltage value corresponding to the display of the first row of pixels of the display device during the vertical blanking period V porch.

[0032] In a preferred embodiment, the timing control module controls the pre-charging start time of the source lines of the source driver circuit according to the gray-scale voltage value of the first row of pixels of the display device during the vertical blanking period. As Figure 2 Shown is a comparison diagram of the charging of the source lines in the driving method of the display device provided by an embodiment of the present invention and the existing charging situation; the dotted line represents the difference between this embodiment and the prior art effect. In this embodiment, by pre-charging the source lines during the vertical blanking period, a pre-charge voltage is obtained, as Figure 2 shown by the dotted curve D1 in the figure. Thus, at the start of the active display period Active, the source lines corresponding to the display of the first row of pixels can be charged on the basis of the pre-charged position, thereby ensuring that the source lines corresponding to the first row of pixels are charged to saturation within the first row display period, solving the problem of unsaturated charging of the source lines during the display of the first row of pixels, and improving the image display effect of the display device.

[0033] In addition, from the comparison relationship shown in the appendix Figure 2 it can be seen that compared with the prior art in which the charging of the source lines is only started at the start of the active display period, by pre-charging the source lines during the vertical blanking period in this embodiment, not only can it be ensured that the source lines corresponding to the display of the first row of pixels are charged to saturation, but also the abnormalities of the power supply voltage and power supply current can be reduced, thereby reducing the power supply requirements and the cost of the display device.

[0034] Please continue to refer to Figure 2 as shown, Figure 2 the dotted line in the figure represents the difference of this embodiment compared with the prior art. Figure 2 The deeply concave solid line in the figure represents the sudden drop in the power supply voltage caused by not performing the pre-charging described in the present invention. Figure 2 The highly convex solid line in the figure represents the sudden increase in the power supply transient current caused by not performing the pre-charging described in the present invention. Figure 2The dashed curve D2 in [the figure] is the curve of the power supply voltage AVDD of the external power supply of the display device after pre-charging the source line during the vertical interval period. From the change trend of the dashed curve D2 and the comparison with the solid line, it can be seen that by pre-charging during the vertical interval period, the peak value of the change and fluctuation of the power supply voltage AVDD during the pre-charging and effective display periods is greatly reduced, improving the power supply stability and further enhancing the image display effect of the display device.

[0035] Figure 2 The dashed curve D3 in [the figure] is the curve of the power supply current I_AVDD of the external power supply of the display device after pre-charging the source line during the vertical interval period. From the change trend of the dashed curve D3 and the comparison with the solid line, it can be seen that by pre-charging during the vertical interval period, the peak value of the change and fluctuation of the power supply current I_AVDD during the pre-charging and effective display periods is greatly reduced. Solving the EMI problem introduced due to the excessive transient current value of the power supply, and it will not generate electromagnetic interference to other chips or circuits in the peripheral circuit, enhancing the stability of the system operation.

[0036] In a preferred embodiment, as Figure 3 shown, according to the magnitude of the gray-scale voltage value of the first-row pixel, set the number of rows of the invalid display period for pre-charging by the timing adjustment source driver circuit of the timing control module during the vertical interval period.

[0037] Thus, in this embodiment, by controlling the pre-charging start time, the source line can be better pre-charged, thereby better solving the problem of incomplete charging of the first-row source line and improving the image display effect of the display device. And reducing the transient current value of the power supply to solve the problem of electromagnetic interference existing in the display driver circuit.

[0038] In some other embodiments, the timing control module controls the source driver circuit to charge the source line of the display device at least one row in advance during the invalid display period of the vertical interval period.

[0039] Preferably, in this embodiment or in some other embodiments, as Figure 2 and Figure 3 shown, the timing control module controls the source driver circuit to charge the source line of the display device two or three rows in advance during the invalid display period of the vertical interval period. The change of the source line voltage after pre-charging the source line of the display device three rows in advance during the invalid display period can be referred to as shown in the source line voltage curve D1.

[0040] Preferably, in this embodiment or in some other embodiments, please continue to refer to Figure 3As shown, it shows the change of the source line voltage curve X2 that charges the source line of the display device during the invalid display period described two lines in advance. From this, it can be known that reducing the pre-charge time can improve the display efficiency of the display device.

[0041] Preferably, in this embodiment or in some other embodiments, please continue to refer to Figure 3 As shown, it shows the change of the source line voltage curve X1 that charges the source line of the display device during the invalid display period described five lines in advance. Increasing the pre-charge time can make the source line voltage of the source line charging more fully saturated, improve the display effect of the display device, and make the power supply voltage value more stable.

[0042] In this embodiment, the timing control module also adjusts the pre-charge time of the source line corresponding to the first row of pixels according to the load capacitance of the source line. If the capacitance value of the load capacitance is large, the pre-charge time is relatively long; if the capacitance value of the load capacitance is small, the pre-charge time is relatively short.

[0043] In this embodiment or in some other embodiments, please continue to refer to Figure 3 As shown, the voltage value of the pre-charge is adjustable, such as Figure 3 the changes of the source line voltage curves X3, D1, and X4 in each. The pre-charge voltage value of the source line corresponding to the first row of pixels can be adjusted, so that the source line voltages of all the first row of pixels in the display device can easily reach the saturation voltage, improving the display effect of the display device and making the power supply voltage value more stable.

[0044] In this embodiment, the voltage value reached after the pre-charge (such as Figure 3 the source line voltage curves X1-X4 and D1 in the invalid display period in) is less than the gray scale voltage of the first row of pixels (such as Figure 3 the potentials of the source lines S1, S3, and S5 in the effective display period in).

[0045] Please continue to refer to Figure 3 As shown, the timing signals required by the display device when displaying an image include: a horizontal synchronization signal HSYNC and a vertical synchronization signal VSYNC.

[0046] The horizontal synchronization signal HSYNC is used to indicate the end of the transmission of one line of pixel data of the display screen / LCD screen. When one line of pixel data of the LCD screen is transmitted, the level of the horizontal synchronization signal HSYNC will change. For example, for a display screen with a resolution of 480RGBx800, the level of the HSYNC will change 800 times when transmitting one frame of image.

[0047] The vertical synchronization signal VSYNC is used to indicate the end of the transmission of one frame of pixel data of the display screen. Each time one frame of pixel data is transmitted, the level of the vertical synchronization signal VSYNC will jump. Here, "frame" is the unit of an image. An image is one frame. In a liquid crystal display, one frame refers to all the liquid crystal pixels of a complete screen.

[0048] One vertical interval period provided in this embodiment includes: a vertical backporch period VBP and a vertical front porch period VFP. The vertical backporch period VBP includes several rows of the invalid display periods (the interval periods shown by reference numerals BP1 to BPn in Figure 3 ); the vertical front porch period VFP includes several rows of the invalid display periods (the interval periods shown by reference numerals FP1 to FPm in Figure 3 ). In this embodiment or some other embodiments, during the vertical backporch period VBP, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row in advance of the invalid display period and then enter the valid display period adjacent to this vertical interval period.

[0049] In this embodiment or some other embodiments, during the vertical front porch period VFP, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row in advance of the invalid display period and then enter the valid display period adjacent to this vertical interval period.

[0050] In this embodiment, as shown in Figures 1 to 2 , the timing control module can input a drive enable signal EN_SOP to the source driver circuit, and when the drive enable signal jumps from the low level to the high level, the first row of source lines is turned on for pre-charging.

[0051] The source lines corresponding to the first row of pixels in this embodiment are turned on only when pre-charging in advance is required through the drive enable signal EN_SOP, thereby saving power consumption and improving the image display effect of the display device.

[0052] In this embodiment or some other embodiments, the range of the grayscale voltage values is set with the midpoint grayscale voltage value as the boundary, including a first grayscale voltage value range with multiple grayscale voltage values less than the midpoint grayscale voltage value and a second grayscale voltage value range with multiple grayscale voltage values greater than or equal to the midpoint grayscale voltage value.

[0053] When the gray-scale voltage value of the first row of pixels is within the first gray-scale voltage value range, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row earlier than the invalid display period during the blanking back porch period of the vertical blanking period, and then enters the effective display period adjacent to the vertical blanking period.

[0054] This ensures that all the source lines of the display device have sufficient time for pre-charging, which can make the source line voltage during source line charging more stable and improve the display effect of the display device.

[0055] When the gray-scale voltage value required by the first row of pixels is within the second gray-scale voltage value range, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row earlier than the invalid display period during the front porch period of the vertical blanking period, and then enters the effective display period adjacent to the vertical blanking period. This ensures that all the source lines of the display device have sufficient time for pre-charging, which can make the power supply voltage more stable and improve the display effect of the display device.

[0056] On the other hand, as Figure 4 shown, this embodiment also provides a display device 10, which includes a display driving circuit and a display screen 140; the display driving circuit includes: a gate driving circuit 120, a source driving circuit 110, and a timing control module 130. The gate driving circuit 120 and the source driving circuit 110 can respectively transmit a scanning signal and display data to the display screen 140. The display screen 140 includes a plurality of pixels arranged in a matrix. Each pixel includes three sub-pixels having three colors of red (R), green (G), and blue (B). The timing control module 130 can control the operations of the gate driving circuit 120 and the source driving circuit 110 to display an image on the display screen 140. As Figure 1 shown, through the control of the gate driving circuit 120 and the scanning lines, each sub-pixel can receive display data from the source driving circuit 110 through the source line. In the display device 10, most of the power consumption comes from the display screen 140. In each display cycle, display data with different voltage levels can charge or discharge the source line and requires a large amount of charge. Each source line is coupled to a column of sub-pixels. Therefore, there is a large amount of parasitic capacitance on the source line, especially for a large-size or high-resolution display screen 140.

[0057] Please continue to refer to Figure 2 shown, the source driving circuit 110 and the timing control module 130 provided in this embodiment apply the driving method as described above to drive the display device 10 to display an image.

[0058] It should be noted that, in this document, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device that includes a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the presence of additional identical elements in the process, method, article or device that includes the said element.

[0059] It should be noted that the devices and methods disclosed in the embodiments of this document can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to multiple embodiments of this document.

[0060] In addition, in each embodiment of this document, the various functional modules can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0061] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A driving method for a display device, the display device including a timing control module and a source driver circuit, characterized in that the operating timing of the source driver circuit includes a plurality of effective display periods and a plurality of vertical blanking periods arranged at intervals, and the vertical blanking periods include a plurality of row blanking periods; the timing control module controls the pre-charging state of the source lines of the source driver circuit according to the gray-scale voltage value of the first row of pixels of the display device during the vertical blanking period.

2. The driving method according to claim 1, wherein According to the magnitude of the gray-scale voltage value of the first row of pixels, set the number of rows of the blanking periods for pre-charging that the timing adjustment source driver circuit of the timing control module turns on during the vertical blanking period.

3. The driving method according to claim 1 or 2, characterized in that, The timing control module controls the source driver circuit to charge the source lines of the display device at least one row of the blanking periods in advance during the vertical blanking period.

4. The driving method according to claim 3, wherein The timing control module controls the source driver circuit to charge the source lines of the display device two rows of the blanking periods in advance during the vertical blanking period.

5. The driving method according to any one of claims 1 to 4, characterized in that The timing control module also adjusts the pre-charging time of the source line corresponding to the first row of pixels according to the load capacitance of the source line. If the capacitance value of the load capacitance is large, the pre-charging time is relatively long; if the capacitance value of the load capacitance is small, the pre-charging time is relatively short.

6. The driving method according to any one of claims 1 to 5, characterized in that, The voltage value of the pre-charging is adjustable.

7. The driving method according to any one of claims 1 to 3, characterized in that One vertical blanking period includes: a post-equalization shoulder period and a pre-equalization shoulder period. The post-equalization shoulder period includes a plurality of row blanking periods; the pre-equalization shoulder period includes a plurality of row blanking periods.

8. The driving method according to claim 7, wherein The timing control module controls the source driver circuit to charge the source lines of the display device at least one row of the blanking periods in advance during the post-equalization shoulder period and then enter the effective display period adjacent to this vertical blanking period.

9. The driving method according to claim 7, characterized in that, The timing control module controls the source driver circuit to charge the source lines of the display device at least one row of the blanking periods in advance during the pre-equalization shoulder period and then enter the effective display period adjacent to this vertical blanking period.

10. The driving method according to claim 1, characterized in that, The gray-scale voltage value range is set with the midpoint gray-scale voltage value as the boundary, including a first gray-scale voltage value range with a plurality of gray-scale voltage values less than the midpoint gray-scale voltage value, and a second gray-scale voltage value range with a plurality of gray-scale voltage values greater than or equal to the midpoint gray-scale voltage value.

11. The driving method according to claim 9, wherein When the gray-scale voltage value of the first row of pixels is in the first gray-scale voltage value range, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row of the blanking periods in advance during the post-equalization shoulder period of the vertical blanking period and then enter the effective display period adjacent to this vertical blanking period; When the saturation gray-scale voltage value required by the first row of pixels is in the second gray-scale voltage value range, the timing control module controls the source driver circuit to charge the source lines of the display device at least one row of the blanking periods in advance during the pre-equalization shoulder period of the vertical blanking period and then enter the effective display period adjacent to this vertical blanking period.

12. The driving method according to claim 1, wherein The voltage value reached after the pre-charging is less than the gray-scale voltage of the first row of pixels.

13. A display device includes a source driver circuit and a timing control module, characterized in that, The source driving circuit and the timing control module apply the driving method according to any one of claims 1 to 12 to drive the display device to display an image.

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