TWI812027B - Display device - Google Patents

Abstract

A display device including a display panel, a source driver, and a gate driver is provided. The display panel includes M*N cholesteric liquid crystal pixels. The source driver is electrically connected to the cholesteric liquid crystal pixels located at M columns, respectively through M data lines. The gate driver is electrically connected to the cholesteric liquid crystal pixels located at N rows, respectively through N gate lines. An n-th gate line among the N gate lines is electrically connected to M cholesteric liquid crystal pixels located at an n-th row. The gate driver continuously generates N pulses to the n-th gate line during a scan duration. Moreover, the gate driver continuously generates K pulses to the n-th gate line during a stabilized duration after the scan duration.

Description

display device

The present invention relates to a display device, and in particular to a display device that passively controls a display panel having cholesteric liquid crystal pixels.

Figure 1A is a schematic diagram of a display panel with passive cholesteric liquid crystal pixels displaying a monochrome image under ideal conditions. Ideally, when the display panel 10a with passive cholesteric liquid crystal is used to display a monochrome image, the image 11 should exhibit uniform brightness. However, when a display device with a passive cholesteric liquid crystal panel using conventional technology displays a monochrome image, the brightness is uneven as shown in Figure 1B.

Figure 1B is a schematic diagram of a conventional display panel with passive cholesteric liquid crystal pixels displaying a monochrome image. In this figure, the monochrome image displayed by the display panel 10b has different brightness depending on the longitudinal position. As the brightness changes, the display panel 10b may present multiple bright lines with varying brightness. For example, the bright stripe 13a has the lowest brightness, the bright stripe 13b has the middle brightness, and the bright stripe 13c has the highest brightness.

Please also note that although the above description uses a display panel displaying a monochrome image as an example, the problem of uneven brightness in display panels with passive cholesteric liquid crystals is universal regardless of whether the displayed image is monochrome or color. . Therefore, there is still a need to improve the control method of conventional passive cholesteric liquid crystal display devices.

The present invention relates to a display device that passively controls a display panel having cholesteric liquid crystal pixels. By using multiple dummy cycles generated by the gate driver before the end of the frame period, rapid changes in the clamping pressure of the cholesteric liquid crystal pixels are reduced, thereby improving the brightness uniformity of the display panel.

According to one aspect of the present invention, a display device is provided. The display device includes: a display panel, a source driver and a gate driver. The display panel includes: M*N cholesteric liquid crystal pixels arranged in M rows and N columns. The source driver is electrically connected to the cholesteric liquid crystal pixels located in M rows via M data lines respectively. The gate driver is electrically connected to the cholesteric liquid crystal pixels located in N columns respectively through N gate lines. The n-th gate line among the N gate lines is electrically connected to the M cholesterol liquid crystal pixels located in the n-th column. The gate driver continuously generates N pulse waves to the n-th gate line during the scanning period, and continuously generates K pulse waves to the n-th gate line during the rest period after the scanning period. M, N, n, and K are positive integers, n is less than or equal to N, and K is less than N.

In order to have a better understanding of the above and other aspects of the present invention, examples are given below and are described in detail with reference to the accompanying drawings:

10a,10b,27:Display panel

11:Screen

13a,13b,13c: bright pattern

20:Display device

21: Timing controller

23: Source driver

25: Gate driver

Sctl_gate: gate control signal

Sctl_src: source control signal

DAT_1,DAT_m,DAT_M: data line (signal)

GAT_1,GAT_n,GAT_N,GAT_(n-1),GAT_(n+1):gate line (signal)

PL(1,1),PL(M,N),PL(m,n),PL(m,(n-1)),PL(m,(n+1)): cholesterol liquid crystal pixel

△V(m,(n-1)),△V(m,n),△V(m,(n+1)),△V(m,1),△V(m,N): Clamping pressure

nsPLS_pre: select the prepulse wave

nsPLS_post: Pulse wave after selection

selPLS: select pulse wave

Tscyc[n-1],Tscyc[n],Tscyc[n+1],Tscyc[1],Tscyc[N],Tscyc: scan period

Vsel: select voltage

Vns: No voltage selected

Trst: reset period

Twait: During the waiting period

Tscan: During scanning

Tframe: frame period

Tsm: during resting period

Tcyc_rst: reset cycle

Tcyc_sm: dummy cycle

t1~t9: time point

WF1, WF2, WF3: waveform

△RI_0,△RI_50,△RI_100: refractive index difference

Figure 1A is a schematic diagram of a display panel with passive cholesteric liquid crystal pixels displaying a monochrome image under ideal conditions; Figure 1B is a schematic diagram of a display panel with passive cholesteric liquid crystal pixels displaying a monochrome image under conventional technology; Figure 2, which is a block diagram of a display device with a passive cholesteric liquid crystal panel; Figure 3A, which is the data signal DAT_m and the gate signal GAT_(n-1) in the cholesteric liquid crystal The pixel PL(m,n-1) forms a pinching pressure △V(m,(n-1)), the data signal DAT_m and the gate signal GAT_n form a pinching pressure △V(m, n), and the schematic diagram of the data signal DAT_m and the gate signal GAT_(n+1) forming the pinch pressure ΔV(m,(n+1)) in the cholesterol liquid crystal pixel PL(m,(n+1)); 3B The figure shows that the cholesterol liquid crystal pixels PL(m,(n-1)), PL(m,n), PL(m,(n+1)) are clamped for a period of time before and after receiving the corresponding pixel data. Schematic diagram of the change process of △V(m,(n-1)), △V(m,n), △V(m,(n+1)); Figure 4, which is a display device based on the concept of this disclosure The waveform diagram corresponding to the signal control of the embodiment; and Figure 5, which compares the refractive index corresponding to the display panel of the conventional technology and the control method of the embodiment of this case, illustrates that the display panel using the embodiment of this case can be compared Schematic diagram of uniformly displaying monochrome images.

As mentioned above, conventional technology passively controls a display panel with cholesteric liquid crystal pixels to display a monochrome image. The brightness distribution will change according to the number of columns in which the cholesteric liquid crystal pixels are located. That is, the pixels in the upper rows of the screen are darker and the pixels in the lower rows of the screen are brighter, thus affecting the user's visual effect. To this end, the present disclosure provides a control method that can achieve a more even distribution of brightness for a passively controlled cholesteric liquid crystal pixel display panel. To simplify the terminology, the display panel referred to below refers to a display panel with cholesteric liquid crystal pixels that is passively controlled.

M，且n

N。 Please refer to Figure 2, which is a block diagram of a display device with a passive cholesteric liquid crystal panel. The display device 20 includes a timing controller 21, a source driver 23, a gate driver 25, and a display panel 27. The display panel 27 includes M*N cholesteric liquid crystal pixels PL(1,1)~PL(M,N), which are arranged in M rows and N columns. For ease of explanation, this article indicates the locations of cholesterol liquid crystal pixels in coordinate format. Among them, the variable M represents the total number of rows of cholesterol liquid crystal pixels; the variable m represents the row where the cholesterol liquid crystal pixels are located; the variable N represents the total number of rows of the cholesterol liquid crystal pixels; and the variable n represents the column where the cholesterol liquid crystal pixels are located. The variables m, n, M, and N are all positive integers, and the relationship between the variables m, n, M, and N is, m

M, and n

N.

For ease of explanation, the same symbols are used in this article to represent signal lines and signals transmitted using the signal lines. After receiving the source control signal Sctl_src from the timing controller 21, the source driver 23 generates data signals DAT_1~DAT_M with data voltages. Then, the data lines DAT_1~DAT_M are used to transmit the data signals to the cholesteric liquid crystal pixels located in rows 1~M. After receiving the gate control signal Sctl_gate from the timing controller 21 , the gate driver 25 generates N gate signals GAT_1 to GAT_N. Then, the gate lines GAT_1~GAT_N are used to transmit the gate signals to the cholesteric liquid crystal pixels located in the 1st to M columns. For a display panel with passively controlled cholesteric liquid crystal pixels, the gate signals GAT_1~GAT_N generated by the gate driver 25 have continuous pulse waves. As the operating period of the display panel changes, the voltages of these pulse waves also change.

Therefore, the cholesteric liquid crystal pixels located in the 1st to M rows are connected to the data lines DAT_1 to DAT_M respectively; and the cholesteric liquid crystal pixels located in the 1st to N columns are connected to the gate lines GAT_1 to GAT_N respectively. Taking the cholesteric liquid crystal pixel PL(m,n) as an example, it is located in the m-th row and n-th column of the display panel 27 and is connected to the data line DAT_m and the gate line GAT_n.

The brightness of a cholesteric liquid crystal pixel depends on its pinch voltage, that is, the voltage difference between the data and gate lines connected to it. Please refer to Figure 3A. The data signal DAT_m and the gate signal GAT_(n-1) form a clamping pressure △V(m,(n-1)) and the data signal in the cholesterol liquid crystal pixel PL(m,n-1). DAT_m and the gate signal GAT_n form a clamping pressure ΔV(m,n) in the cholesterol liquid crystal pixel PL(m,n), and the data signal DAT_m and the gate signal GAT_(n+1) form a clamping pressure ΔV(m,n) in the cholesterol liquid crystal pixel PL(m, (n+1)) forms a schematic diagram of the clamping pressure ΔV(m, (n+1)). The cholesteric liquid crystal pixels PL(m,(n-1)), PL(m,n), and PL(m,(n+1)) are all electrically connected to the data line DAT_m, and the cholesteric liquid crystal pixels PL(m,(n) -1)), PL(m,n), PL(m,(n+1)) are connected to the gate lines GAT_(n-1), GAT_n), and GAT_(n+1) respectively.

As shown in Figure 3A, the voltage difference between the data signal DAT_m and the gate signal GAT_(n-1) forms the clamping voltage ΔV(m,(n-1) of the cholesteric liquid crystal pixel PL(m,n-1) )). The voltage difference between the data signal DAT_m and the gate signal GAT_n) forms the clamping voltage ΔV(m,n) of the cholesteric liquid crystal pixel PL(m,n). The voltage difference between the data signal DAT_m and the gate signal GAT_(n+1) forms the clamping voltage ΔV(m,(n+1)) of the cholesteric liquid crystal pixel PL(m,n+1).

Please refer to Figure 3B, which shows the cholesteric liquid crystal pixels PL(m,(n-1)), PL(m,n), PL(m,(n+1)) receiving the corresponding pixel data. During this period, the schematic diagram shows the changing process of the clamping pressure △V(m,(n-1)), △V(m,n), and △V(m,(n+1)). The vertical axis of this graph is voltage and the horizontal axis is time. The waveform in this diagram represents the clamping pressure ΔV(m,(n-1)) of the cholesterol liquid crystal pixel PL(m,n-1) and the clamping pressure of the cholesterol liquid crystal pixel PL(m,n) from top to bottom. △V(m,n), and the clamping pressure △V(m,(n+1)) of the cholesterol liquid crystal pixel PL(m,(n+1)).

Please also note that since this article assumes that the display panel 27 displays a monochrome image, it means that all the cholesteric liquid crystal pixels on the display panel receive the same voltage of the data signal DAT_m from the data signal line DAT_m. Therefore, here only the changes in the gate signals GAT_(n-1), GAT_n), and GAT_(n+1) are considered here. , the influence of △V(m,(n+1)).

For the convenience of explanation, the thicker lines here represent the pulse waves received when the cholesterol liquid crystal pixel is selected (selected pulse wave selPLS), and the thinner lines represent the pulses received when the cholesterol liquid crystal pixels are not selected. Wave. Among them, according to different time points, the pulse wave received before the pixel is selected is represented as the pre-selection pulse wave nsPLS_pre, and the pulse wave received after the pixel is selected is represented as the post-selection pulse wave nsPLS_post. Table 1 lists the relationship between courage and courage in tabular form. Alcohol liquid crystal pixels PL(m,n-1), PL(m,n), PL(m,(n+1)) in different scanning periods Tscyc[n-1], Tscyc[n], Tscyc[n+ 1] Type of pulse wave received, and changes in clamping pressure V(m,(n-1)), △V(m,n), △V(m,(n+1)).

Before time point t2, the cholesterol liquid crystal pixel PL(m,n-1) continues to receive the selected front pulse wave nsPLS_pre from the gate signal GAT_(n-1); during the period from time point t2 to time point t3 (scan cycle Tscyc[n-1] ), receiving the selected pulse wave selPLS from the gate signal GAT_(n-1); and, after time point t3, continuing to receive the selected post-pulse wave nsPLS_post from the gate signal GAT_(n-1). Before time point t3, the cholesterol liquid crystal pixel PL(m,n) continuously receives and selects the pre-pulse wave nsPLS_pre from the gate signal GAT_n; during the period from time point t3 to time point t4 (scan period Tscyc[n]), it receives and selects the self-gate signal GAT_n. pulse wave selPLS; and, after time point t4, the self-gate signal GAT_n continues to receive the selected Get the post pulse wave nsPLS_post. In the same way, the cholesterol liquid crystal pixel PL(m,(n+1)) continues to receive the selected front pulse wave nsPLS_pre from the gate signal GAT_n before time point t4; during the period from time point t4 to time point t5 (scan period Tscyc[n+1] ), the selected pulse wave selPLS is received from the gate signal GAT_n; and, after time point t5, the post-selection pulse wave nsPLS_post is continuously received from the gate signal GAT_n.

Following the above, the scan periods Tscyc[1]~Tscyc[N] corresponding to each gate line GAT_1~GAT_N are generated in turn, and the periods of each scan period Tscyc[1]~Tscyc[N] are equal in length. When the gate line GAT_n transmits the selection pulse wave selPLS in the scan period Tscyc[n], the gate lines GAT_1~GAT_(n-1) have all been selected, but the gate lines GAT_(n+1)~GAT_N have not yet been selected. Therefore, during the scan period Tscyc[n], the gate lines GAT_1~GAT_(n-1) transmit the post-selection pulse wave nsPLS_post to the cholesterol liquid crystal pixel PL(1~M,1~(n-1)); GAT_n transmits the selection pulse wave selPLS to the cholesterol liquid crystal pixel PL(1~M,n); and, the gate lines GAT_(n+1)~GAT_N transmits the pre-selection pulse wave nsPLS_pre to the cholesterol liquid crystal pixel PL(1~M,(n +1)~N).

Further comparison of the pre-selected pulse wave nsPLS_pre, the selected pulse wave selPLS, and the selected post-pulse wave nsPLS_post can reveal the following relationship. The selected voltage Vsel corresponding to the selected pulse wave selPLS is higher than the unselected voltage Vns corresponding to the pre-selected pulse wave nsPLS_pre and the post-selected pulse wave nsPLS_post. That is, Vsel>Vns.

Please refer to FIG. 4 , which is a waveform diagram of signal control corresponding to an embodiment of a display device according to the concept of the present disclosure. The vertical axis of this diagram is voltage and the horizontal axis is time. Listed here are the clamping pressure ΔV(m,1) of the cholesterol liquid crystal pixel PL(m,1) located in the mth row and first column, and the clamping pressure ΔV(m,1) of the cholesterol liquid crystal pixel PL(m,n) located in the mth row and nth column. The process of the clamping pressure ΔV(m,n) and the clamping pressure ΔV(m,N) of the cholesterol liquid crystal pixel PL(m,N) located in the m-th row and Nth column, changing with time. As mentioned above, it is assumed here that the display panel 27 displays a monochrome picture, representing the cholesteric liquid crystal pixels on the display panel. The pixel data received from the data signal are all the same. Therefore, only the impact of changes in the gate signal on the clamping pressure needs to be considered here.

A frame period Tframe (time point t1 ~ time point t9) of the display panel 27 includes a reset period Trst (time point t1 ~ time point t2), a waiting period Twait (time point t2 ~ time point t3), and a scanning period Tscan (time point t3 ~ time point t8) , and the resting period Tsm (time point t8 ~ time point t9). That is, Tframe=Trst+Twait+Tscan+Tsm.

The display panel 27 is in the reset period Trst (time t1 ~ time t2) at the beginning of the frame period Tframe (time t1 ~ time t9). The gate lines GAT_1, GAT_n, and GAT_N each transmit R reset pulses during the reset period Trst, and each reset pulse corresponds to a reset period Tcyc_rst. Among them, R is a positive integer. Therefore, reset period Tcyc (Trst=R*Tcyc). In addition, the voltages of the reset pulse waves transmitted by the gate lines GAT_1, GAT_n, and GAT_N during the reset period Trst are equal, and the voltage of the reset pulse wave is higher than the voltage of the selected pulse wave.

After the reset period Trst (time point t1 to time point t2) ends, the display panel 27 enters the waiting period Twait (time point t2 to time point t3). The voltages of the gate lines GAT_1~GAT_N remain unchanged during the waiting period Twait, so the clamping pressures △V(m,1), △V(m,n), △V(m,N) of the cholesterol liquid crystal pixels remain unchanged during the waiting period Twait remain unchanged (for example, 0V).

After the waiting period Twait (time point t2 to time point t3) ends, the display panel 27 enters the scanning period Tscan (time point t3 to time point t8). During the scanning period, Tscan includes a total of N scanning periods Tscyc[1]~Tscyc[N]. Among them, the length Tscyc of each scan period Tscyc[1]~Tscyc[N] is less than or equal to the length of the reset period Tcyc_rs.

Continuing the description of Figure 3B, it can be seen that the waveform in the first column represents the gate line GAT_1 transmitting the selected pulse wave selPLS to the cholesterol liquid crystal pixel PL(m,1) in the scanning period Tscyc[1] (time point t3 ~ time point t4) ; and, transmit the post-selection pulse wave nsPLS_post to the cholesterol liquid crystal pixel PL(m,1) in the scanning period Tscyc[2]~Tscyc[N] (time point t4~time point t8). In the same way, the second column The waveform is that the gate line GAT_n transmits the selected pre-pulse wave nsPLS_pre to the cholesterol liquid crystal pixel PL(m,n) during the scanning period Tscyc[1]~Tscyc[n-1] (time point t3~time point t5); during the scanning period Tscyc [n] (time point t5~time point t6), transmit the selected pulse wave selPLS to the cholesterol liquid crystal pixel PL(m,n); and, during the scanning period Tscyc[n+1]~Tscyc[N] (time point t6~time point t8) , transmit the selected pulse wave nsPLS_post to the cholesterol liquid crystal pixel PL(m,n). Furthermore, the waveform in the third column is that the gate line GAT_N transmits the pre-selection pulse wave nsPLS_pre to the cholesterol liquid crystal pixel PL(m, N); and, transmit the selected pulse wave selPLS to the cholesterol liquid crystal pixel PL(m,N) in the scanning period Tscyc[N] (time point t7 ~ time point t8).

According to the concept of the present disclosure, after the scanning period Tscan ends (time point t8), a resting period Tsm (time point t8~time point t9) is provided. After the rest period Tsm ends (time point t9), the next frame period Tframe starts. The gate lines GAT_1~GAT_N each send out K dummy pulses during the rest period Tsm (time point t8~time point t9). Among them, K is a positive integer, and the dummy cycle (dummy cycle) Tcyc_sm corresponding to the dummy pulse wave is the same as the scan cycle Tscyc. In addition, the rest period Tsm is longer than the reset period Trst, and R<K.

The N columns of cholesteric liquid crystal pixels on the display panel 27 are respectively connected to the gate lines GAT_1~GAT_N, and the gate lines GAT_1~GAT_N each transmit K dummy pulse waves during the rest period Tsm. In other words, during the rest period Tsm, all the cholesteric liquid crystal pixels PL(1,1)~PL(M,N) on the display panel 27 receive K dummy pulse waves respectively from the corresponding gate lines GAT_1~GAT_N.

As the cholesterol liquid crystal pixels PL(1,1)~PL(M,N) receive the dummy pulse wave, the state of the liquid crystal molecules of the cholesterol liquid crystal pixels PL(1,1)~PL(M,N) will gradually tend to stability. Taking the M cholesteric liquid crystal pixels PL(1,N)~PL(M,N) located in the Nth column as an example, through the setting of the rest period Tsm, the cholesteric liquid crystal pixels PL(1,N)~PL(M, N) After receiving the selection voltage Vsel, K dummy pulse waves will be received before the next frame period Tframe starts. therefore, The cholesteric liquid crystal pixels PL(1,n)~PL(M,n) (where n=1~N) located in the nth column will be maintained for a period of time after receiving the selected pulse wave selPLS and its corresponding pixel data. (Tsm during resting period) stable state.

The state and brightness of cholesterol liquid crystal pixels change as their clamping pressure changes. In the last scanning period Tscyc[N] before the scanning period Tscan (time point t7 ~ time point t8), the clamping pressure of the cholesterol liquid crystal pixels PL(1,N)~PL(M,N) located in the Nth column is maximum. At the moment when the clamping pressure reaches the maximum value, if the rest period Tsm is not set, but the reset period Trst of the next frame period is entered instantaneously, the cholesterol liquid crystal pixels PL(1,N)~PL located in the Nth column will (M,N) will be converted to the Planar state due to such switching. At the same time, the brightness of the Nth column will be the brightest, and the user will see a very bright white stripe at the bottom of the display panel.

On the other hand, in this case, due to the setting of the rest period Tsm, the cholesterol liquid crystal pixels PL(1,N)~PL(M,N) located in the Nth column will still maintain the K dummy pulses transmitted from the gate signal GAT_N are received. Relatedly, during the period of receiving the dummy pulse wave, the cholesterol liquid crystal pixels PL(1,N)~PL(M,N) located in the Nth column can tend to the focal conic state. Accordingly, once the rest period Tsm ends and the reset period Trst of the next frame period begins, the states of the cholesteric liquid crystal pixels PL(1,N)~PL(M,N) will not switch drastically in an instant. In other words, through the dummy pulse wave transmitted by Tsm during the rest period, the cholesterol liquid crystal pixels PL(1,N)~PL(M,N) will not instantly become bright white.

Accordingly, when the user watches the image of the display panel 27, the liquid crystal molecules in the cholesteric liquid crystal pixels PL(1,1)~PL(M,N) in each column tend to a stable focal conic state, thereby eliminating the problem of 1B The bright streak phenomenon shown. Therefore, when the value of K is larger, the brightness of the display panel is more uniform. In other words, when the value of K is larger, the cholesterol liquid crystal pixels in the first column (PL(1,1)~PL(M,1)) and the cholesterol liquid crystal pixels in the Nth column (PL(1,N)~ The closer the brightness of PL(M,N)) is.

Please refer to Figure 5, which is a schematic diagram illustrating that the display panel 27 of the present embodiment can display a monochrome image more uniformly by comparing the refractive index corresponding to the display panel of the conventional technology and the control method of the present embodiment. In this figure, the vertical axis represents the refractive index (RI), and the horizontal axis represents the number of columns (n) of the display panel 27 . Among them, the higher the refractive index, the brighter the image seen by the user. Moreover, if the difference between the maximum value and the minimum value of the same refractive index waveform (defined as the refractive index difference ΔRI) is smaller, it means that the brightness distribution of the image seen by the user on the display panel 27 is more uniform.

This diagram is obtained by testing the display panel 27 with a total number of columns of 960 (N=960). As mentioned before, the variable K represents the number of dummy cycles added to Tsm during the rest period. Waveform WF1 corresponds to the situation when Tframe does not add dummy periods (K=0) during the picture frame period; waveform WF2 corresponds to the situation when Tframe adds 50 dummy periods (K=50) during the picture frame period; waveform WF3 corresponds to the situation when Tframe adds 50 dummy periods (K=50) during the picture frame period. Tframe adds 100 dummy periods (K=100).

It can be seen from this diagram that when Tframe does not add a dummy period (K=0) during the frame period, the refractive index difference ΔRI_0 of the display panel 27 is the largest; during the frame period, Tframe adds 50 dummy periods (K=50) When , the refractive index difference ΔRI_50 of the display panel 27 is the smallest; and when 100 dummy periods (K=100) are added to Tframe during the frame period, the refractive index difference ΔRI_100 of the display panel 27 is the smallest. That is, △RI_0>△RI_50>△RI_100. In other words, the brightness uniformity of the display panel 27 when K=100 is higher than the brightness uniformity of the display panel 27 when K=50. In addition, it can be seen from the comparison of waveforms WF2 and WF3 that when the value of K is larger, the overall refractive index of the display panel 27 is lower, and the brightness of the display panel 27 is also lower.

48時，即可明顯看出亮度之均勻度大幅提升，不再出現如第1B圖所示的亮紋現象。 According to the measurement results in Figure 5, it can be seen that when the number of dummy periods is larger (K is larger), the brightness presented by the display panel 27 is more uniform. In actual application, the value of K can be determined based on the product of the total number of columns N of the display panel 27 multiplied by a preset percentage and taken as an integer. For example, assuming N=960 and the preset percentage is 5%, you can get 960*5%=48. For display panel 27 with N=960, if K is set to

At 48 hours, it can be clearly seen that the uniformity of brightness has been greatly improved, and the bright streaks as shown in Figure 1B no longer appear.

Following the above, this disclosure sets a resting period Tsm (K dummy periods Tcyc_sm) after the scanning period Tscan, so that the cholesterol liquid crystal pixels located in different columns can maintain receiving for a period of time after the scanning period Tscan ends. Dummy pulse wave. The presence of Tsm during the standing period can improve the brightness uniformity of the passive cholesteric liquid crystal display panel, thereby improving the user's visual effect.

In summary, although the present invention has been disclosed above through embodiments, they are not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the appended patent application scope.

△V(m,1),△V(m,n),△V(m,N): clamping pressure

selPLS: select pulse wave

Tscyc[1],Tscyc[n],Tscyc[N],Tscyc: scan cycle

Trst: reset period

Twait: During the waiting period

Tscan: During scanning

Tframe: frame period

Tsm: during resting period

Tcyc_rst: reset cycle

Tcyc_sm: dummy cycle

t1~t9: time point

Claims (9)

A display device, including: a display panel including: M*N cholesteric liquid crystal pixels, arranged in M rows and N columns; a source driver electrically connected to the M data lines located in the M rows respectively; and other cholesteric liquid crystal pixels; and, a gate driver electrically connected to the cholesteric liquid crystal pixels located in the N columns via N gate lines, wherein an n-th gate in the N gate lines The lines are electrically connected to M cholesteric liquid crystal pixels located in an n-th column, wherein the gate driver continuously generates N pulse waves to the n-th gate line during a scanning period, and, after the scanning period ends During a rest period, K pulse waves are continuously generated to the n-th gate line, where M, N, n, and K are positive integers, n is less than or equal to N, and K is less than N. When the value of K exceeds When the brightness is larger, the brightness of the M cholesteric liquid crystal pixels located in a first column and the M cholesteric liquid crystal pixels located in an Nth column are closer. The display device as described in claim 1, wherein the N pulse waves include: (n-1) pre-selection pulse waves, which are generated sequentially after the start of the scanning period; a selection pulse wave, which is The (n-1) pre-selection pulse waves are generated after the end; and the (N-n) post-selection pulse waves are generated after the selection pulse wave beam, wherein the level of the selection pulse wave is higher than the (n-1 ) voltages of the pre-selection pulse waves and the voltages of the (N-n) post-selection pulse waves, and the voltages of the (n-1) pre-selection pulse waves are equal to the voltages of the (N-n) post-selection pulse waves. The display device of claim 2, wherein the periods of the N pulse waves are equal to the periods of the K pulse waves, and the voltages of the K pulse waves are equal to the voltages of the (n-1) pre-selected pulse waves. and the voltage of the (N-n) selected pulse waves. The display device of claim 2, wherein a frame period includes a reset period, the scanning period and the rest period, and the gate driver controls the n-th gate line during the reset period. Generate R reset pulse waves, where R is a positive integer and R is less than K. The display device of claim 4, wherein the voltage of the R reset pulse waves is higher than the voltage of the selected pulse wave, and the period of the R reset pulse waves is greater than or equal to the period of the selected pulse wave. The display device of claim 4, wherein the frame period further includes a waiting period between the reset period and the scanning period. The display device of claim 6, wherein the clamping pressure of the cholesteric liquid crystal pixels remains unchanged during the waiting period. The display device of claim 1, wherein K is greater than or equal to the product of M and a preset percentage. The display device of claim 8, wherein the preset percentage is 5%.