Display device and driving method thereof

Abstract

A display device and a driving method thereof are provided. In a display device, a display panel has a plurality of pixels. The scan driver provides a plurality of scan signals to the plurality of pixels. In the scanning period, the scanning driver scans the scanned pixel according to the scanning signal, and the source driver provides a source driving signal to the scanned pixel according to the display gray scale degree of the scanned pixel. The source driver sets the voltage peak value of the source driving signal according to the display gray scale degree of the scanned pixel, and the display gray scale degree of the scanned pixel is in negative correlation with the voltage peak value of the source driving signal. Or, the source driver sets the duration time of the source driving signal according to the display gray scale degree of the scanned pixel, and the display gray scale degree of the scanned pixel is in negative correlation with the duration time of the source driving signal.

Description

Technical Field

[0001] The present invention relates to a driving technology, and particularly to a display device and a driving method thereof. Background Art

[0002] In existing cholesteric liquid crystal displays (ChLCDs), cholesteric liquid crystals generally can include a planar state, a focal conic state, and a homeotropic state. Generally, existing cholesteric liquid crystal displays usually present a bright display image in the planar state and a dark display image in the focal conic state.

[0003] However, since the focal conic state of cholesteric liquid crystals is a non-complete transparent state but a scattering state with scattering, and in the driving mode of the focal conic state, there is backscattering when the display shows a dark display image, which affects the contrast of the display image.

[0004] In view of this, how to effectively improve the contrast of the display image of a cholesteric liquid crystal display and thereby improve the display quality of the display image will be an important issue for those skilled in the relevant art. Summary of the Invention

[0005] The present invention provides a display device and a driving method thereof, which can effectively improve the contrast of the display image and thereby improve the display quality of the display device.

[0006] The display device of the present invention includes a display panel, a scan driver, and a source driver. The display panel has a plurality of pixels. The scan driver is coupled to the display panel and provides a plurality of scan signals to the pixels. The source driver is coupled to the display panel. During the scan period of the display time interval, the scan driver scans at least one scanned pixel among the pixels according to the scan signals, and the source driver provides at least one source driving signal to at least one scanned pixel according to the display gray scale level of at least one scanned pixel. Wherein the source driver sets the voltage peak value of the source driving signal according to the display gray scale level of at least one scanned pixel, and the display gray scale level of at least one scanned pixel is negatively correlated with the voltage peak value of the source driving signal, or the source driver sets the duration of the source driving signal according to the display gray scale level of at least one scanned pixel, and the display gray scale level of at least one scanned pixel is negatively correlated with the duration of the source driving signal.

[0007] A driving method for a display device according to the present invention includes: providing a display panel having a plurality of pixels; providing a scan driver to cause the scan driver to provide a plurality of scan signals to the pixels, and causing the scan driver to scan at least one scanned pixel among the pixels according to the scan signals during a scan period of a display time interval; providing a source driver to cause the source driver to provide at least one source driving signal to at least one scanned pixel according to the display gray level degree of at least one scanned pixel during the scan period; and causing the source driver to set the voltage peak value of the source driving signal according to the display gray level degree of at least one scanned pixel, wherein the display gray level degree of at least one scanned pixel is negatively correlated with the voltage peak value of the source driving signal; or causing the source driver to set the duration of the source driving signal according to the display gray level degree of at least one scanned pixel, wherein the display gray level degree of at least one scanned pixel is negatively correlated with the duration of the source driving signal.

[0008] Based on the above, the display device and its driving method according to the embodiments of the present invention can use a driving method of PAM or PWM through the source driver, so that the liquid crystal in the pixels of the display panel can present a dark-state display image in a vertically arranged manner based on a relatively large pixel voltage difference. In this way, compared with the existing cholesteric liquid crystal display, the display device of the present invention will not be affected by backscattering in the dark-state picture performance, thereby improving the contrast of the display panel and improving the display quality of the display image. Description of the Drawings

[0009] Figure 1 is a schematic diagram of a display device according to an embodiment of the present invention.

[0010] Figure 2 is according to the present invention Figure 1 is a timing diagram of the display device in the first driving mode.

[0011] Figure 3 is according to the present invention Figure 1 is a waveform schematic diagram of the pixel voltage difference of each pixel in the embodiment of the present invention in the first driving mode.

[0012] Figure 4 is according to the present invention Figure 1 is a timing diagram of the display device in the second driving mode.

[0013] Figure 5 is according to the present invention Figure 1 is a waveform schematic diagram of the pixel voltage difference of each pixel in the embodiment of the present invention in the second driving mode.

[0014] Figure 6 is a flowchart of a driving method for a display device according to an embodiment of the present invention.

[0015] Figure 7 It is a flowchart of a driving method for a display device according to another embodiment of the present invention.

[0016] Explanation of reference numerals:

[0017] 100: Display device

[0018] 110: Display panel

[0019] 120: Scan driver

[0020] 130: Source driver

[0021] CLC: Liquid crystal capacitance

[0022] CONT: Continuation period

[0023] DL1, DL2: Source lines

[0024] DATA1, DATA2: Source driving signals

[0025] DSP1, DSP2: Display time intervals

[0026] GL1, GL2: Scan lines

[0027] GS1, GS2: Scan signals

[0028] L0, L64, L128, L255: Waveforms

[0029] N1 to N4, SCAN2: Negative polarity sub-periods

[0030] PX11, PX12, PX21, PX22: Pixels

[0031] P1 to P4, SCAN1: Positive polarity sub-periods

[0032] RESETA, RESETB: Reset periods

[0033] SCANA, SCANB: Scan periods

[0034] S610 to S640, S710 to S740: Steps

[0035] T: Transistor

[0036] VCOM: Common voltage Detailed implementation manners

[0037] The term "coupled (or connected)" used throughout this disclosure (including claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be indirectly connected to the second device through other devices or some connection means. In addition, wherever possible, elements / components / steps with the same numbers in the drawings and embodiments represent the same or similar parts. Elements / components / steps with the same numbers or the same terms in different embodiments can refer to the relevant descriptions of each other.

[0038] Figure 1 is a schematic diagram of a display device 100 according to an embodiment of the present invention. Figure 1 The display device 100 includes a display panel 110, a scan driver 120 and a source driver 130. In this embodiment, the display panel 110 includes a plurality of pixels. For the convenience of description and the clarity of the drawings, Figure 1 The pixels PX11, PX12, PX21 and PX22 are used as examples. Figure 1 The number of pixels, source lines, and scan lines shown may be determined according to the design requirements of the display panel 110, and the present invention is not limited to Figure 1 The number of pixels, source lines, and scan lines shown.

[0039] For example, the pixels PX11 , PX12 , PX21 , and PX22 in the display panel 110 may be arranged in a matrix and disposed at intersections of the plurality of source lines DL1 ˜ DL2 and the plurality of scan lines GL1 ˜ GL2 .

[0040] Regarding the circuit configuration in each pixel PX11, PX12, PX21 and PX22, the pixel PX11 is used as an example for explanation, and the circuit configuration in the remaining pixels PX12, PX21 and PX22 can be deduced accordingly. For example, the pixel PX11 may include a transistor T and a liquid crystal capacitor CLC. Among them, the control end (e.g., gate end) of the transistor T is coupled to the scan line GL1, the first end (e.g., source end) of the transistor T is coupled to the first end of the liquid crystal capacitor CLC, and the second end (e.g., drain end) of the transistor T is coupled to the data line DL1. The first end of the liquid crystal capacitor CLC is coupled to the first end of the transistor T, and the second end of the liquid crystal capacitor CLC is coupled to the common voltage VCOM.

[0041] It is worth mentioning that, for the sake of convenience in description, in the display panel 110 of this embodiment, the display gray scale level of pixel PX11 can be set to gray scale value 0, for example, the display gray scale level of pixel PX12 can be set to gray scale value 64, for example, the display gray scale level of pixel PX21 can be set to gray scale value 128, and the display gray scale level of pixel PX22 can be set to gray scale value 255, for example. Among them, the lower the gray scale value of a pixel, the darker the brightness displayed by the pixel, and the higher the gray scale value of a pixel, the brighter the brightness displayed by the pixel. Therefore, in this embodiment, pixel PX11 can be used to represent a pixel with a display brightness presenting a dark state, and pixel PX22 can be used to represent a pixel with a display brightness presenting a bright state.

[0042] It should be noted that Figure 1 The display gray scale levels of the respective pixels shown can be determined according to the design requirements of the display panel 110, and the present invention is not limited to the above setting method. In this embodiment, the display panel 110 can be, for example, a cholesteric liquid crystal panel.

[0043] On the other hand, the scan driver 120 is coupled to the scan lines GL1, GL2 of the display panel 110. The scan driver 120 can respectively provide scan signals GS1, GS2 to the display panel 110 through the scan lines GL1, GL2 to respectively perform scan operations on pixels PX11, PX12 and PX21, PX22.

[0044] The source driver 130 is coupled to the source lines DL1, DL2 of the display panel 110. The source driver 130 can respectively provide source drive signals DATA1, DATA2 to the display panel 110 through the source lines DL1, DL2.

[0045] Figure 2 is the timing diagram of the display device 100 according to the present invention Figure 1 in the first driving mode. Please refer to Figure 2 , in Figure 2 the embodiment shown, a display time interval DSP1 of the display device 100 can be divided into a reset period RESETA and a scan period SCANA. The display device 100 can operate in the reset period RESETA and the scan period SCANA in sequence, and the reset period RESETA and the scan period SCANA do not overlap with each other. Among them, the scan period SCANA can include a plurality of positive sub-periods P1 to P4 and a plurality of negative sub-periods N1 to N4.

[0046] It is especially mentioned that in Figure 2 the timing diagram, Figure 2 the horizontal axis of Figure 2The vertical axis represents the voltage values (V) of the scan signals GS1, GS2, the source drive signals DATA1, DATA2, and the common voltage VCOM.

[0047] On the other hand, Figure 3 is in accordance with the present invention Figure 1 is a waveform diagram of the pixel voltage difference of each pixel in the first driving method according to an embodiment of the present invention. Please refer to Figure 3 , in Figure 3 In the shown waveform diagram, the waveforms L0, L64, L128, and L255 can respectively represent the change states of the pixel voltage differences of the pixel PX11 (i.e., gray scale value 0), pixel PX12 (i.e., gray scale value 64), pixel PX21 (i.e., gray scale value 128), and pixel PX22 (i.e., gray scale value 255) of the display panel 110 in the display time interval DSP1. Among them, in Figure 3 In the shown waveform diagram, the waveforms L0, L64, L128, and L255 are respectively illustrated by different types of line segment representation methods.

[0048] For example, the waveform L0 can represent the voltage difference between the second end (e.g., drain end) of the pixel PX11 and both ends of the common voltage VCOM (i.e., pixel voltage difference △V11); the waveform L64 can represent the voltage difference between the second end (e.g., drain end) of the pixel PX12 and both ends of the common voltage VCOM (i.e., pixel voltage difference △V12); the waveform L128 can represent the voltage difference between the second end (e.g., drain end) of the pixel PX21 and both ends of the common voltage VCOM (i.e., pixel voltage difference △V21); the waveform L255 can represent the voltage difference between the second end (e.g., drain end) of the pixel PX22 and both ends of the common voltage VCOM (i.e., pixel voltage difference △V22).

[0049] It should be particularly mentioned that in Figure 3 the waveform diagram of Figure 3 the horizontal axis represents the operation time (T) of the display device 100, and Figure 3 the vertical axis represents the voltage values (V) of the pixel voltage differences △V11, pixel voltage difference △V12, pixel voltage difference △V21, and pixel voltage difference △V22.

[0050] Regarding Figure 1 the implementation details of the display device 100 shown in Figures 1 to 3, Specifically, when the display device 100 operates during the reset period RESETA of the display time interval DSP1, the scan driver 120 can generate enabled (e.g., high voltage level) scan signals GS1, GS2 to the pixels PX11, PX12 and PX21, PX22 of the display panel 110. And, the source driver 130 can generate source drive signals DATA1, DATA2 with a voltage value of 24V to the second ends of the pixels PX11, PX12, PX21 and PX22 corresponding to the enabled scan signals GS1, GS2 during the first polarity (i.e., positive polarity) of the reset period RESETA.

[0051] In addition, during the first polarity of the reset period RESETA, the display device 100 can set the voltage value of the common voltage VCOM to -24V.

[0052] In this case, as Figure 3 shown, when the display device 100 operates during the first polarity of the reset period RESETA, the voltage values of the pixel voltage differences (i.e., △V11, △V12, △V21 and △V22) of the respective pixels PX11, PX12, PX21 and PX22 in the display panel 110 are all adjusted to 48V.

[0053] Next, as Figure 2 shown, the source driver 130 can generate source drive signals DATA1, DATA2 with a voltage value of -24V to the second ends of the pixels PX11, PX12, PX21 and PX22 corresponding to the enabled scan signals GS1, GS2 during the second polarity (i.e., negative polarity) of the reset period RESETA.

[0054] In addition, during the second polarity of the reset period RESETA, the display device 100 can set the voltage value of the common voltage VCOM to 24V.

[0055] In this case, as Figure 3 shown, when the display device 100 operates during the second polarity of the reset period RESETA, the voltage values of the pixel voltage differences (i.e., △V11, △V12, △V21 and △V22) of the respective pixels PX11, PX12, PX21 and PX22 in the display panel 110 are all adjusted to -48V.

[0056] In other words, when the display device 100 operates at the first polarity or the second polarity during the reset period RESETA, the source driver 130 can reset the absolute values of the pixel voltage differences ΔV11, ΔV12, ΔV21, and ΔV22 of the respective pixels PX11, PX12, PX21, and PX22 to the maximum voltage difference value (i.e., the voltage value is 48V) by adjusting the voltage magnitudes of the source drive signals DATA1, DATA2, and the common voltage VCOM. Under this set condition, based on the driving technology of cholesterol liquid crystal, the display device 100 can display an image with the liquid crystal in the planar spiral state arrangement in these pixels PX11, PX12, PX21, and PX22 during the reset period RESETA.

[0057] On the other hand, after completing the relevant reset actions during the reset period RESETA, the display device 100 can continue to perform the scanning operation during the scanning period SCANA of the display time interval DSP1. Specifically, when the display device 100 operates during the scanning period SCANA of the display time interval DSP1, the scan driver 120 can generate sequentially enabled scan signals GS1, GS2 to the pixels PX11, PX12, and PX21, PX22 of the display panel 110 to scan the pixels PX11, PX12, and PX21, PX22.

[0058] Next, during the scanning period SCANA, the source driver 130 can set the voltage peak value of the source drive signal corresponding to the scanned pixel according to the display gray scale level (or the gray scale value of the display gray scale) of at least one scanned pixel among these pixels PX11, PX12, and PX21, PX22.

[0059] For the convenience of description, the following will take the pixels PX11 and PX22 as examples of scanned pixels to conduct relevant descriptions. And the embodiments taking the pixels PX12 and PX21 as scanned pixels can be deduced by analogy.

[0060] Please refer to Figures 1 to 3 , for example, assuming that the display device 100 takes the pixel PX11 as the scanned pixel, during the positive sub-period P1 of the scanning period SCANA, the transistor T of the scanned pixel PX11 can be turned on according to the enabled scan signal GS1. Then, the source driver 130 can set the voltage peak value of the corresponding source drive signal DATA1 to 20V according to the display gray scale level of the scanned pixel PX11 (i.e., the gray scale value 0).

[0061] In addition, during the positive sub-period P1 of the scanning period SCANA, the display device 100 can set the voltage value of the common voltage VCOM to -20V.

[0062] In this case, as Figure 3 shown by waveform L0, when the display device 100 operates in the positive sub-period P1 of the scanning period SCANA, the voltage value of the pixel voltage difference ΔV11 of the scanned pixel PX11 is adjusted to 40V (i.e., waveform L0).

[0063] In contrast, as Figure 2 shown, during the negative sub-period N1 of the scanning period SCANA, the transistor T of the scanned pixel PX11 can be turned on according to the enabled scanning signal GS1. Then, the source driver 130 can set the voltage peak value of the corresponding source driving signal DATA1 to -20V according to the display gray level of the scanned pixel PX11 (i.e., gray level value 0).

[0064] In addition, during the negative sub-period N1 of the scanning period SCANA, the display device 100 can set the voltage value of the common voltage VCOM to 20V.

[0065] In this case, as Figure 3 shown by waveform L0, when the display device 100 operates in the negative sub-period N1 of the scanning period SCANA, the voltage value of the pixel voltage difference ΔV11 of the scanned pixel PX11 is adjusted to -40V (i.e., waveform L0).

[0066] On the other hand, assuming that the display device 100 takes the pixel PX22 as the scanned pixel, during the positive sub-period P1 of the scanning period SCANA, the transistor T of the scanned pixel PX22 can be turned on according to the enabled scanning signal GS2. Then, the source driver 130 can set the voltage peak value of the corresponding source driving signal DATA2 to -20V according to the display gray level of the scanned pixel PX22 (i.e., gray level value 255).

[0067] In addition, during the positive sub-period P1 of the scanning period SCANA, the display device 100 can set the voltage value of the common voltage VCOM to -20V.

[0068] In this case, as Figure 3 shown by waveform L255, when the display device 100 operates in the positive sub-period P1 of the scanning period SCANA, the voltage value of the pixel voltage difference ΔV22 of the scanned pixel PX22 is adjusted to 0V (i.e., waveform L255).

[0069] In contrast, as Figure 2As shown, during the negative sub-period N1 of SCANA in the scanning period, the transistor T of the scanned pixel PX22 can be turned on according to the enabled scanning signal GS2. Subsequently, the source driver 130 can set the voltage peak of the corresponding source driving signal DATA2 to 20V according to the display gray scale level of the scanned pixel PX22 (i.e., the gray scale value 255).

[0070] In addition, during the negative sub-period N1 of SCANA in the scanning period, the display device 100 can set the voltage value of the common voltage VCOM to 20V.

[0071] In this case, as Figure 3 shown by the waveform L255, when the display device 100 operates during the negative sub-period N1 of the scanning period SCANA, the voltage value of the pixel voltage difference △V22 of the scanned pixel PX22 is adjusted to 0V (i.e., the waveform L255).

[0072] It should be noted that for the implementation details of the scanned pixels PX11 and PX22 operating during the positive sub-periods P2 - P4 and negative sub-periods N2 - N4 of the scanning period SCANA, reference can be made to the relevant descriptions mentioned above for the scanned pixels PX11 and PX22 operating during the positive sub-period P1 and negative sub-period N1 of the scanning period SCANA for analogy, so they will not be elaborated here.

[0073] In addition, for the changing states of the pixel voltage differences △V12 and △V21 corresponding to the pixels PX12 and PX21 respectively during the scanning period SCANA, reference can be made to the relevant descriptions mentioned above for the pixel voltage differences △V11 and △V22 corresponding to the pixels PX11 and PX22 respectively during the scanning period SCANA for analogy, so they will not be elaborated here.

[0074] In other words, in Figures 1 to 3 this embodiment, when the display device 100 operates during the scanning period SCANA, the display gray scale level (or the gray scale value of the display gray scale) of the scanned pixels in the display panel 110 is negatively correlated with the voltage peak of the corresponding source driving signal.

[0075] According to the above description, it can be known that the source driver 130 of this embodiment can use the PAM driving method to set the voltage peak of the corresponding source driving signal according to the display gray scale level of the scanned pixel. Therefore, the display gray scale of each pixel in the display panel 110 can be driven by the corresponding driving voltage.

[0076] In addition, in this embodiment, since the source driver 130 can apply a pixel voltage difference ΔV11 with a voltage value of 40V to the pixel PX11 according to the display gray scale level of the pixel PX11 (i.e., the gray scale value 0) during the scan period SCANA, the liquid crystal in the pixel PX11 can present a dark display screen in a vertically aligned arrangement according to the relatively large pixel voltage difference ΔV11.

[0077] In this way, compared with the existing cholesterol liquid crystal display that presents a dark display screen in a vertically helical state, the liquid crystal molecules of the pixels in the display device 100 of this embodiment can present a dark display screen in a vertically aligned arrangement. Therefore, the display performance of the display panel 110 in the dark state will not be affected by backscattering, thereby improving the contrast of the display panel 110 and enhancing the display quality of the display screen.

[0078] Figure 4 is the display device 100 according to the present invention Figure 1 under the second driving method. Please refer to Figure 4 , in Figure 4 In the illustrated embodiment, a display time interval DSP2 of the display device 100 can be divided into a reset period RESETB, a scan period SCANB, and a continuation period CONT. The display device 100 can operate in sequence in the reset period RESETB, the scan period SCANB, and the continuation period CONT, and the reset period RESETB, the scan period SCANB, and the continuation period CONT do not overlap with each other.

[0079] In Figure 4 In the illustrated timing diagram, the scan period SCANB can include a plurality of positive sub-periods SCAN1 and a plurality of negative sub-periods SCAN2. It should be particularly noted that Figure 4 the horizontal axis of Figure 4 represents the operating time (T) of the display device 100, and

[0080] On the other hand, Figure 5 is the display device 100 according to the present invention Figure 1 under the second driving method. Please refer to Figure 5 , in Figure 5 In the illustrated waveform diagram, the pixel voltage differences ΔV11, ΔV12, ΔV21, and ΔV22 of the pixels PX11, PX12, PX21, and PX22 of the display panel 110 respectively represent the change states in the display time interval DSP2.

[0081] In particular, Figure 5 the horizontal axis of Figure 5 represents the operation time (T) of the display device 100, while

[0082] Regarding Figure 1 the implementation details of the display device 100 shown in the second driving method (for example, the driving method of Pulse-width modulation (PWM)), please also refer to Figure 1 , Figure 4 and Figure 5 . Among them, for the implementation details of the reset period RESETB when the display device 100 operates in the display time interval DSP2, it can be analogized with reference to the relevant description of the reset period RESETA when the display device 100 operates in the display time interval DSP1 mentioned in Figures 1 to 3 , so it will not be elaborated here.

[0083] Next, after finishing the relevant reset actions of the reset period RESETB, the display device 100 can continue to perform the scanning operation of the scanning period SCANB in the display time interval DSP2.

[0084] It should be particularly mentioned here that different from Figures 1 to 3 In the embodiment of Figure 4 , the source driver 130 uses the PAM driving method during the scanning period SCANA to set the voltage peak value of the corresponding source driving signal according to the display gray level of the scanned pixel. In this embodiment, as

[0085] shown in Figure 4 , the source driver 130 can provide the source driving signals DATA1 and DATA2 with a fixed voltage value (i.e., 10V or -10V) to the pixels PX11, PX12, PX21, and PX22 during the scanning period SCANB. Figure 4 shown in

[0086] For ease of explanation, the following will use the pixels PX11 and PX22 as examples of the pixels to be scanned for relevant description. The examples with pixels PX12 and PX21 as the pixels to be scanned can be inferred by analogy.

[0087] Please refer to Figure 1 , Figure 4 and Figure 5 For example, assuming that the display device 100 uses the pixel PX11 as the pixel to be scanned, during the positive sub-period SCAN1 or the negative sub-period SCAN2 of the scanning period SCANB, the transistor T of the pixel PX11 to be scanned can be turned on according to the enabled scanning signal GS1. Then, the source driver 130 can provide a source driving signal DATA1 with a fixed voltage value (i.e., 10V or -10V) to the pixel PX11 to be scanned according to the enabled scanning signal GS1.

[0088] In this case, as shown in the waveform diagram of Figure 5 , when the display device 100 operates during the positive sub-period SCAN1 or the negative sub-period SCAN2 of the scanning period SCANB, the voltage peak of the pixel voltage difference △V11 of the pixel PX11 to be scanned can be adjusted to 20V or -20V.

[0089] In addition, in the embodiments of Figure 4 and Figure 5 , during the scanning period SCANB, the source driver 130 can set the time length of the duration TC of the corresponding source driving signal DATA1 according to the display gray level of the pixel PX11 to be scanned (i.e., gray level value 0).

[0090] Furthermore, the source driver 130 can adjust the time length of the duration TC of the source driving signal DATA1 according to the display gray level of the pixel PX11 to be scanned (i.e., gray level value 0), so that the time length of the duration TC during which the pixel voltage difference △V11 of the pixel PX11 to be scanned maintains at the voltage peak (i.e., 20V or -20V) can be lengthened.

[0091] On the other hand, assuming that the display device 100 uses the pixel PX22 as the pixel to be scanned, during the positive sub-period SCAN1 or the negative sub-period SCAN2 of the scanning period SCANB, the transistor T of the pixel PX22 to be scanned can be turned on according to the enabled scanning signal GS2. Then, the source driver 130 can provide a source driving signal DATA2 with a fixed voltage value (i.e., 10V or -10V) to the pixel PX22 to be scanned according to the enabled scanning signal GS2.

[0092] In this case, as shown in Figure 5As shown in the waveform diagram, when the display device 100 operates in the positive sub-period SCAN1 or the negative sub-period SCAN2 of the scan period SCANB, the voltage peak of the pixel voltage difference ΔV22 of the scanned pixel PX22 can be adjusted to 0V.

[0093] In addition, in Figure 4 and Figure 5 In the embodiment, during the scan period SCANB, the source driver 130 can set the duration TC of the corresponding source drive signal DATA2 according to the display gray level (i.e., gray level value 255) of the scanned pixel PX22.

[0094] For example, the source driver 130 can adjust the duration TC of the source drive signal DATA2 according to the display gray level (i.e., gray level value 255) of the scanned pixel PX22, so that the duration TC of the pixel voltage difference ΔV22 of the scanned pixel PX22 maintaining at the voltage peak can be zero.

[0095] In other words, in Figure 1 、 Figure 4 and Figure 5 In the embodiment, when the display device 100 operates in the scan period SCANB, the display gray level (or gray level value of the display gray level) of the scanned pixel in the display panel 110 is negatively correlated with the duration of the corresponding source drive signal (or pixel voltage difference).

[0096] Therefore, in this embodiment, the source driver 130 of this embodiment can use the PWM driving method to adjust the duration of the corresponding source drive signal (or pixel voltage difference) according to the display gray level of the scanned pixel. Therefore, the display gray level of each pixel in the display panel 110 can be driven by the corresponding driving voltage and duration.

[0097] On the other hand, after completing the relevant scanning operation of the scan period SCANB, the display device 100 can continue to perform the operation of the continuation period CONT of the display time interval DSP2.

[0098] Specifically, in Figure 4 and Figure 5 In the embodiment, when the display gray level (or gray level value of the display gray level) of the scanned pixel in the display panel 110 is lower than a preset gray level threshold, the source driver 130 of this embodiment can continuously provide a source drive signal for pulse width modulation to the scanned pixel during the continuation period CONT.

[0099] Among them, the above grayscale threshold can be set according to the design requirements of the display panel 110. In this embodiment, when the display grayscale level of the scanned pixel is lower than the grayscale threshold, it indicates that the scanned pixel can operate in a low grayscale state (e.g., dark state).

[0100] For example, as Figure 4 shown, assuming that when the display device 100 takes the pixel PX11 as the scanned pixel, based on the display grayscale level of the scanned pixel PX11 of the display panel 110 (i.e., grayscale value 0) being lower than the grayscale threshold, the source driver 130 can, according to the display grayscale level of the scanned pixel PX11, continuously provide the pulse-width modulated source drive signal DATA1 to the scanned pixel PX11 during the continuation period CONT.

[0101] In this case, as Figure 5 shown, during the continuation period CONT, the voltage state of the pixel voltage difference △V11 of the scanned pixel PX11 can continue the voltage state during the scan period SCANB to maintain switching between 20V and -20V.

[0102] On the other hand, as Figure 4 shown, assuming that when the display device 100 takes the pixel PX22 as the scanned pixel, based on the display grayscale level of the scanned pixel PX22 of the display panel 110 (i.e., grayscale value 255) not being lower than the grayscale threshold, the source driver 130 can, according to the display grayscale level of the scanned pixel PX22, make the source drive signal DATA2 a fixed reference voltage during the continuation period CONT.

[0103] In this case, as Figure 5 shown, during the continuation period CONT, the voltage state of the pixel voltage difference △V22 of the scanned pixel PX22 can continue the voltage state during the scan period SCANB to maintain at 0V. That is, the source driver 130 can continuously apply the pixel voltage difference △V22 with a voltage value of 0V to the scanned pixel PX22 during the continuation period CONT.

[0104] In addition, the implementation details of the pixel PX12 and the pixel PX21 during the continuation period CONT can be analogized with reference to the relevant description of the pixel PX22 during the continuation period CONT mentioned in Figures 4 to 5 and will not be elaborated here.

[0105] That is to say, in this embodiment, during the continuation period CONT, the source driver 130 only continuously provides a relatively large pixel voltage difference to the scanned pixels whose displayed gray level is lower than the preset gray level threshold (i.e., the pixels for displaying the dark state brightness), so that the pixel voltage difference of the scanned pixels can continuously maintain the voltage state during the scan period SCANB.

[0106] According to the above description, it can be known that in this embodiment, the liquid crystal in the scanned pixels (such as pixel PX11) whose displayed gray level is lower than the gray level threshold can present a dark state display screen in a vertically aligned arrangement according to the relatively large pixel voltage difference.

[0107] In this way, compared with the existing cholesteric liquid crystal display that presents a dark state display screen in a vertical helical state, the liquid crystal molecules of the pixels in the display device 100 of this embodiment can present a dark state display screen in a vertically aligned arrangement. Therefore, the display panel 110 will not be affected by backscattering in the dark state picture performance, thereby improving the contrast of the display panel 110 and improving the display quality of the display screen.

[0108] Figure 6 It is a flowchart of a driving method of the display device 100 according to an embodiment of the present invention. Please refer to Figure 1 and Figure 6 , in step S610, the display device provides a display panel having a plurality of pixels. In step S620, the display device provides a scan driver, so that the scan driver provides a plurality of scan signals to the plurality of pixels, and the scan driver scans at least one scanned pixel among the plurality of pixels according to the plurality of scan signals during the scan period of the display time interval.

[0109] In step S630, the display device provides a source driver, so that the source driver provides at least one source drive signal to at least one scanned pixel according to the displayed gray level of at least one scanned pixel during the scan period. In step S640, the display device enables the source driver to set the voltage peak value of the source drive signal according to the displayed gray level of at least one scanned pixel, where the displayed gray level of at least one scanned pixel is negatively correlated with the voltage peak value of the source drive signal.

[0110] Figure 7 It is a flowchart of a driving method of the display device 100 according to another embodiment of the present invention. Please refer to Figure 1 and Figure 7, in step S710, the display device provides a display panel having a plurality of pixels. In step S720, the display device provides a scan driver, causing the scan driver to provide a plurality of scan signals to the plurality of pixels, and causing the scan driver to scan at least one scanned pixel among the plurality of pixels according to the plurality of scan signals during the scan period of the display time interval.

[0111] In step S730, the display device provides a source driver, causing the source driver to provide at least one source drive signal to at least one scanned pixel according to the display gray scale level of at least one scanned pixel during the scan period. In step S740, the display device causes the source driver to set the duration of the source drive signal according to the display gray scale level of at least one scanned pixel, where the display gray scale level of at least one scanned pixel is negatively correlated with the duration of the source drive signal.

[0112] The implementation details of the above steps have been described in detail in the foregoing embodiments and implementation manners, and will not be elaborated herein.

[0113] In summary, the display device and its driving method according to the embodiments of the present invention can use the driving methods of PAM or PWM by the source driver, so that the liquid crystal in the pixels of the display panel can present a dark display screen in a vertically aligned arrangement manner based on a relatively large pixel voltage difference. In this way, compared with the existing cholesteric liquid crystal display, the display device of the present invention will not be affected by backscattering in the dark state picture performance, thereby improving the contrast of the display panel and improving the display quality of the display screen.

Claims

1. A display device, comprising: a display panel having a plurality of pixels; A scan driver, coupled to the display panel, providing a plurality of scan signals to the pixels; as well as a source driver coupled to the display panel, In a scanning period of a display time interval, the scan driver scans at least one scanned pixel among the pixels according to the scan signals, and the source driver provides at least one source driving signal to the at least one scanned pixel according to a display grayscale level of the at least one scanned pixel. wherein the source driver sets a voltage peak value of the source driving signal according to the display grayscale level of the at least one scanned pixel, and the display grayscale level of the at least one scanned pixel is negatively correlated with the voltage peak value of the source driving signal; or The source driver sets a duration of the source driving signal according to the displayed grayscale level of the at least one scanned pixel, and the displayed grayscale level of the at least one scanned pixel is negatively correlated with the duration of the source driving signal. 2 . The display device as claimed in claim 1 , wherein the display time interval further comprises a reset period, and the source driver makes the absolute value of the voltage difference between the two ends of each pixel a maximum voltage difference during the reset period.

3. The display device as claimed in claim 2, wherein in a first polarity during the reset period, the voltage difference between the two ends of each pixel is a positive value, and in a second polarity during the reset period, the voltage difference between the two ends of each pixel is a negative value.

4. The display device as described in claim 1, wherein during the scanning period, the source driver corresponds to a first display grayscale, so that a first scanned pixel has a voltage difference of a first voltage, and the source driver corresponds to a second display grayscale, so that a second scanned pixel has a voltage difference of a second voltage, wherein the first display grayscale is greater than the second display grayscale, and the first voltage is less than the second voltage.

5. A display device as described in claim 4, wherein the scanning period includes multiple positive polarity sub-periods and multiple negative polarity sub-periods, in each of the positive polarity sub-periods, the voltage at the first end of the first scanned pixel is greater than the voltage at the second end of the first scanned pixel, and in each of the negative polarity sub-periods, the voltage at the second end of the first scanned pixel is greater than the voltage at the first end of the first scanned pixel.

6. A display device as described in claim 1, wherein the scanning period includes multiple positive polarity sub-periods and multiple negative polarity sub-periods, and the source driver corresponds to a first display grayscale, so that the source drive signal has the duration in each of the positive polarity sub-period and the negative polarity sub-period, and the length of the duration is not longer than the time length of each of the positive polarity sub-period and the negative polarity sub-period. 7 . The display device as claimed in claim 6 , wherein during the duration, the source driving signal has a fixed voltage value.

8. The display device as claimed in claim 7, wherein the display time interval further includes a continuation period, and when the display grayscale level of the at least one scanned pixel is lower than a grayscale threshold, the source driver continues to provide the at least one source driving signal in pulse width modulation during the continuation period.

9. The display device as claimed in claim 8, wherein when the display grayscale level of the at least one scanned pixel is not lower than the grayscale threshold, the source driver makes the at least one source driving signal a fixed reference voltage during the extension period.

10. The display device as claimed in claim 1, wherein the display panel is a cholesteric liquid crystal panel.

11. A method for driving a display device, comprising: Providing a display panel having a plurality of pixels; A scan driver is provided, so that the scan driver provides a plurality of scan signals to the pixels, and the scan driver scans at least one scanned pixel among the pixels according to the scan signals during a scan period of a display time interval; Providing a source driver, so that the source driver provides at least one source driving signal to the at least one scanned pixel according to a display grayscale level of the at least one scanned pixel during the scanning period; as well as The source driver sets a voltage peak value of the source driving signal according to the display grayscale level of the at least one scanned pixel, wherein the display grayscale level of the at least one scanned pixel is negatively correlated with the voltage peak value of the source driving signal; or The source driver sets a duration of the source driving signal according to the displayed grayscale level of the at least one scanned pixel, wherein the displayed grayscale level of the at least one scanned pixel is negatively correlated with the duration of the source driving signal.

12. The driving method as claimed in claim 11, wherein the display time interval further includes a reset period, wherein the driving method further includes: During the reset period, the source driver makes the absolute value of the voltage difference between the two ends of each pixel a maximum voltage difference. 13 . The driving method as claimed in claim 12 , wherein in a first polarity during the reset period, the voltage difference between the two ends of each pixel is a positive value, and in a second polarity during the reset period, the voltage difference between the two ends of each pixel is a negative value.

14. The driving method according to claim 11, further comprising: The source driver causes a first scanned pixel to have a voltage difference of a first voltage corresponding to a first display gray scale during the scanning period; as well as The source driver causes a second scanned pixel to have a voltage difference of a second voltage corresponding to a second display gray scale during the scanning period. The first display grayscale is greater than the second display grayscale, and the first voltage is less than the second voltage.

15. The driving method according to claim 14, wherein the scanning period includes a plurality of positive polarity sub-periods and a plurality of negative polarity sub-periods, wherein the driving method further comprises: In each of the positive polarity sub-periods, the voltage on the first end of the first scanned pixel is made greater than the voltage on the second end of the first scanned pixel; as well as In each of the negative polarity sub-periods, the voltage at the second end of the first scanned pixel is made greater than the voltage at the first end of the first scanned pixel.

16. The driving method according to claim 11, wherein the scanning period includes a plurality of positive polarity sub-periods and a plurality of negative polarity sub-periods, wherein the driving method further comprises: The source driver corresponds to a first display gray scale, so that the source driving signal has the duration in each of the positive polarity sub-period and the negative polarity sub-period, wherein the duration is not longer than the duration of each of the positive polarity sub-period and the negative polarity sub-period. 17 . The driving method as claimed in claim 16 , wherein during the duration, the source driving signal has a fixed voltage value.

18. The driving method as claimed in claim 17, wherein the display time interval further includes a continuation period, and when the display grayscale level of the at least one scanned pixel is lower than a grayscale threshold, the source driver continues to provide the at least one source driving signal in pulse width modulation during the continuation period.

19. The driving method as claimed in claim 17, wherein when the display grayscale level of the at least one scanned pixel is not lower than the grayscale threshold, the source driver makes the at least one source driving signal a fixed reference voltage during the extended period.

20. The driving method as claimed in claim 11, wherein the display panel is a cholesteric liquid crystal panel.

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