CN113674709A - Driving module for active matrix driving cholesterol liquid crystal display device and driving method thereof - Google Patents

Driving module for active matrix driving cholesterol liquid crystal display device and driving method thereof Download PDF

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Publication number
CN113674709A
CN113674709A CN202010499426.1A CN202010499426A CN113674709A CN 113674709 A CN113674709 A CN 113674709A CN 202010499426 A CN202010499426 A CN 202010499426A CN 113674709 A CN113674709 A CN 113674709A
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China
Prior art keywords
liquid crystal
cholesteric liquid
driven
stable
crystal pixels
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CN202010499426.1A
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Inventor
连水池
赖梓杰
黄俊宏
陈仁禄
邱钟毅
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Hongyao Electric Paper Technology Co ltd
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Hongyao Electric Paper Technology Co ltd
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • G09G3/3651—Control of matrices with row and column drivers using an active matrix using multistable liquid crystals, e.g. ferroelectric liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3614—Control of polarity reversal in general

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The invention provides a driving module which is used for an active matrix driving cholesterol liquid crystal display device. The driving module includes a gate driving circuit, a source driving circuit and a timing controller. The gate driving circuit is used for generating a plurality of gate driving signals; the source driving circuit is used for generating a plurality of data driving signals; the time schedule controller is used for controlling the plurality of gate driving signals and the plurality of data driving signals, so that a plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by reset voltage firstly to reach a stable equidirectional arrangement state and then are driven by a plurality of corresponding decision voltages respectively to reach a stable plane state or a focal conic state.

Description

Driving module for active matrix driving cholesterol liquid crystal display device and driving method thereof
Technical Field
The present invention relates to a driving module for an active matrix cholesteric liquid crystal display device and a driving method thereof, and more particularly, to a driving module with a fast refresh rate and a driving method thereof for an active matrix cholesteric liquid crystal display device.
Background
Active matrix liquid crystal displays (AM-LCDs) using nematic (nematic) liquid crystals have been widely used in many applications. However, the use of a backlit and transmissive active matrix liquid crystal display is not conducive to long-term reading by people, particularly children. Recently, paper-like displays have been widely used in consideration of the advantages of paper and the characteristics of electronic devices that can update information.
One application of the paper-like Display is a Cholesteric Liquid Crystal Display (Cholesteric Liquid Crystal Display). The cholesteric liquid crystal display has the characteristics of bi-stability, high contrast and high color. The cholesteric liquid crystal display consumes power only when changing the picture, and the cholesteric liquid crystal display can still display the picture under the condition of no applied voltage. The characteristics of the cholesterol liquid crystal can be applied to a reflective display. Therefore, for static image display, the reflective cholesteric liquid crystal display has a very good power-saving characteristic.
In the prior art, fujitsu showed a passive matrix cholesteric liquid crystal display, which showed a rather good image. However, since the update speed is too slow, the movie cannot be played. In view of the above, there is a need for improvement in the prior art.
Disclosure of Invention
Therefore, it is a primary objective of the claimed invention to provide a driving module with fast refresh rate for an active matrix cholesteric liquid crystal display device and a driving method thereof.
The invention also discloses a driving module for the active matrix driving cholesterol liquid crystal display device. The driving module includes a gate driving circuit, a source driving circuit and a timing controller. The gate driving circuit is used for generating a plurality of gate driving signals; the source driving circuit is used for generating a plurality of data driving signals; the time schedule controller is used for controlling the plurality of gate driving signals and the plurality of data driving signals, so that a plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by reset voltage firstly to reach a stable equidirectional arrangement state and then are driven by a plurality of corresponding decision voltages respectively to reach a stable plane state or a focal conic state.
The invention also discloses a driving method for the active matrix driving cholesterol liquid crystal display device, which comprises generating a plurality of gate driving signals; generating a plurality of data driving signals; and controlling the plurality of gate driving signals and the plurality of data driving signals to make a plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device driven by the reset voltage to reach a stable equidirectional arrangement state and then driven by a plurality of corresponding decision voltages respectively to reach a stable plane state or a focal conic state.
Drawings
Fig. 1 is a schematic diagram of an active matrix driving cholesteric liquid crystal display device according to an embodiment of the invention.
FIG. 2 is a diagram illustrating the relationship between the reflectivity of cholesteric liquid crystal and voltage according to an embodiment of the present invention.
FIG. 3 is a timing diagram of gate driving signals in a frame according to an embodiment of the present invention.
FIG. 4A is a polarity diagram of a cholesteric liquid crystal pixel matrix in a frame undergoing column inversion driving according to an embodiment of the invention.
FIG. 4B is a polarity diagram illustrating column inversion driving of the cholesteric liquid crystal pixel matrix in a frame adjacent to the frame shown in FIG. 4A according to an embodiment of the invention.
FIG. 5A is a polarity diagram of the row-column inversion driving of the cholesteric liquid crystal pixel matrix in a frame according to an embodiment of the invention.
FIG. 5B is a polarity diagram of row-column inversion driving of the cholesteric liquid crystal pixel matrix in the frame adjacent to the frame shown in FIG. 5A, in accordance with an embodiment of the present invention.
FIG. 6A is a polarity diagram of the cholesteric liquid crystal pixel matrix performing dot inversion driving in one frame according to an embodiment of the invention.
FIG. 6B is a polarity diagram of the cholesteric liquid crystal pixel matrix dot-inversion-driven in the frame adjacent to the frame shown in FIG. 5A according to the embodiment of the invention.
FIG. 7 is a timing diagram of gate driving signals in a frame according to another embodiment of the present invention.
FIG. 8 is a timing diagram of gate driving signals in a frame according to another embodiment of the present invention.
Fig. 9 is a schematic diagram of a driving flow according to an embodiment of the invention.
Detailed Description
Referring to fig. 1, fig. 1 is a schematic diagram of an active matrix driven cholesteric liquid crystal display (cholesteric liquid crystal display) device 10 according to an embodiment of the invention. For convenience of illustration, the active matrix driving cholesteric liquid crystal display device 10 is simplified to include a source driving circuit 100, a gate driving circuit 102, a timing controller 104, and data lines S1～SMScanning line G1～GNAnd a cholesteric liquid crystal pixel matrix Mat, wherein the source driving circuit 100, the gate driving circuit 102 and the timing controller 104 are regarded as the driving module 12. The cholesteric liquid crystal pixel matrix Mat includes a plurality of cholesteric liquid crystal pixels, each of which includes cholesteric liquid crystal, and the circuit thereof can be simplified to be composed of a transistor T, a storage capacitor Cst, and a liquid crystal capacitor Cls, wherein the storage capacitor Cst and the liquid crystal capacitor Cls are coupled to a common voltage Vcom. The Transistor T is a switching element, and may be a Thin Film Transistor (TFT), including but not limited to amorphous Silicon (a-Si), Oxide (Oxide), and Low Temperature Poly-Silicon (LTPS, which may be NMOS or PMOS) TFTs, and if the Transistor T is a Low Temperature Poly-Silicon PMOS device, the voltage polarity described below is reversed or adjusted appropriately.
Referring to fig. 2, fig. 2 is a schematic diagram of a relationship between a reflectivity and a voltage of a Cholesteric Liquid Crystal Display (CH-LCD) according to an embodiment of the invention. As shown in fig. 2, the cholesteric liquid crystal state can be changed by modulating the voltage across the storage capacitor Cst and the liquid crystal capacitor Cls, and the Planar state (Planar) reflects light with a specific wavelength and the Focal-conic state (Focal-conic) scatters light, so that the reflectivity can be modulated by voltage. When the cholesteric liquid crystal is modulated, the cholesteric liquid crystal is driven to a Homeotropic (Homeotropic) state by a large resetting (resetting) voltage, and then driven to a planar state or a focal conic state required by a user by a small determining (terminating) voltage to modulate the required reflectivity. Therefore, the full-color reflective cholesteric liquid crystal pixel with bistable characteristic can be manufactured.
In this case, the timing controller 104 can utilize the horizontal synchronization signal Hsync and the output enable signal Ena to control the source driving circuit 100 and the gate driving circuit 102 respectively to generate the data driving signal Sig _ S1～Sig_SMAnd gate drive signal Sig _ G1～Sig_GNTo charge the corresponding cholesteric liquid crystal pixels in the cholesteric liquid crystal pixel matrix Mat. In other words, the transistors T in each cholesteric liquid crystal pixel are turned on by the corresponding gate driving signal for one time to perform reset scanning, so that the cholesteric liquid crystal is driven by the corresponding data driving signal with a larger reset voltage to reach a stable homodromous arrangement state, and then the transistors T in each cholesteric liquid crystal pixel are turned on by the corresponding gate driving signal for one time to perform decision scanning, and then are driven by the corresponding data driving signal with a smaller decision voltage according to a picture desired by a user to reach a stable plane state or focal conic state and corresponding gray scale and brightness, so that the cholesteric liquid crystal pixel matrix Mat can display the picture desired by the user. Therefore, the invention drives each cholesterol liquid crystal pixel by a larger reset voltage to reach a stable equidirectional arrangement state, and then drives by a smaller decision voltage to reach a stable plane state or focal conic state and a corresponding gray scale and brightness mode to actively drive the cholesterol liquid crystal pixel matrix Mat, thereby having a fast update rate and being capable of smoothly carrying out picture display such as film playing and the like.
In detail, referring to fig. 3, fig. 3 shows an embodiment of the present invention in a frame (frame) F1Middle gate driving signal Sig _ G1～Sig_GNTiming diagram of (2). As shown in FIG. 3, the gate driving signal Sig _ G1～Sig_GNFirstly, respectively aligning the corresponding scan lines G1～GNA reset scan is performed, in which case the data driving signal Sig _ S1～Sig_SMDriving corresponding cholesterol liquid crystal pixels with a larger reset voltage, waiting for a reset retention time Thr to determine that all the cholesterol liquid crystal pixels reach a stable same-direction arrangement state, and then generating a gate drive signal Sig _ G1～Sig_GNThen respectively corresponding to the corresponding scanning lines G1～GNPerforming a decision scan, wherein the data driving signal Sig _ S1～Sig_SMDriving the corresponding cholesteric liquid crystal pixels with a smaller decision voltage according to the picture desired by the user, and then all the cholesteric liquid crystal pixels can convert the frame F1The remaining time is used as the determination retention time Thd, and then the stable planar state or focal conic state and the corresponding gray scale and brightness are achieved to display the picture desired by the user.
Specifically, the cholesteric liquid crystal pixel needs a proper long reset transition time and a proper long decision transition time to be stable (for example, the reset transition time needs 3ms), but the time for the cholesteric liquid crystal pixel to receive the data driving signal can be very short, so the scanning line G is scanned during the reset scanning1～GNThe reset scan times tsr of about 20 mus, respectively, may be turned on only at scan line G1～GNWhen the total number N is 600, the total reset scan time tsr × N is about 12ms, the reset retention time Thr can be set to 0-2 ms to ensure that all the cholesteric liquid crystal pixels achieve a stable alignment state, and then the scan lines G are scanned during the reset scan1～GNThe decision scan times tsd may be turned on only about 20 μ s each, and the total decision scan time tsd N is also about 12ms in the frame F1Under the condition that the length is 33ms, the remaining determined retention time Thd is 9-7 ms, so that all the cholesteric liquid crystal pixels reach a stable planar state or a focal conic state and corresponding gray scales and brightness to display the picture desired by the user.
It is worth noting that the main essence of the present inventionThe present invention is directed to a method for driving cholesteric liquid crystal pixels in an active mode by driving cholesteric liquid crystal pixels in a stable homeotropic alignment state with a large reset voltage and then in a stable planar state or focal conic state and corresponding gray scales and brightness with a small determination voltage. For example, since the polarity of the voltage applied to the two ends of the liquid crystal layer must be reversed at intervals (where positive polarity refers to the voltage Vp of the pixel electrode suspended in the cholesteric liquid crystal being higher than the common voltage Vcom, and negative polarity refers to the voltage Vp of the pixel electrode suspended in the cholesteric liquid crystal being lower than the common voltage Vcom), the liquid crystal layer is prevented from being polarized and permanently damaged, and the image sticking effect is also avoided. Thus, the data driving signal Sig _ S1～Sig_SMThe corresponding cholesteric liquid crystal pixels can be charged with different polarities, so that the polarity inversion operations such as Column inversion (Column inversion), Row inversion (Row inversion) or Dot inversion (Dot inversion) can be performed in the same frame, and the same cholesteric liquid crystal pixels in adjacent frames are driven with different polarities.
In detail, referring to fig. 4A and 4B, fig. 4A shows a frame F according to an embodiment of the present inventioncFIG. 4B is a schematic diagram showing the polarity of a middle-cholesterol liquid crystal pixel matrix Mat driven by a column inversion, in which the frame F shown in FIG. 4A is the frame FcAdjacent frame AF ofcPolarity diagram of the middle cholesterol liquid crystal pixel matrix Mat for one column inversion driving. As shown in FIG. 4A, the data driving signal Sig _ S1～Sig_SMWill correspond to the data line S1～SMThe cholesterol liquid crystal pixels in the middle and odd rows (columns) are driven by positive polarity voltage, and the cholesterol liquid crystal pixels in the even rows are driven by negative polarity voltage. In this case, in the same frame, the same cholesteric liquid crystal pixel receives the same data driving signal with the same polarity for the column inversion effect although the reset voltage and the determination voltage have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 4B, AF is performed in the adjacent framecMiddle, data driving signal Sig _ S1～Sig_SMWill correspond to the data line S1～SMThe cholesterol liquid crystal pixels in the odd-numbered rows are driven by negative voltage and the cholesterol liquid crystal pixels in the even-numbered rows are driven by positive voltage, so that the effect of polarity inversion of the same cholesterol liquid crystal pixels in two adjacent frames can be achieved.
On the other hand, referring to fig. 5A and 5B, fig. 5A shows a frame F according to an embodiment of the present inventionrFIG. 5B is a schematic polarity diagram of the middle-cholesterol liquid crystal pixel matrix Mat driven by column inversion, in which the frame F shown in FIG. 5A is the frame FrAdjacent frame AF ofrPolarity diagram of the row-column (row) inversion driving of the medium-cholesterol liquid crystal pixel matrix Mat. As shown in FIG. 5A, the data driving signal Sig _ S1～Sig_SMWill correspond to the scanning line G1～GNThe cholesterol liquid crystal pixels in the middle and odd rows are driven by positive voltage, and the cholesterol liquid crystal pixels in the even rows are driven by negative voltage. In this case, in the same frame, the same cholesteric liquid crystal pixels receive the same polarity of the corresponding data driving signals with the same polarity for the row inversion effect, although the reset voltages and the determination voltages have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 5B, AF is performed in the adjacent framerMiddle, data driving signal Sig _ S1～Sig_SMWill correspond to the scanning line G1～GNThe cholesterol liquid crystal pixels in the odd-numbered rows are driven by negative voltage, and the cholesterol liquid crystal pixels in the even-numbered rows are driven by positive voltage, so that the effect of polarity inversion of the same cholesterol liquid crystal pixels in two adjacent frames can be achieved.
On the other hand, referring to fig. 6A and 6B, fig. 6A shows a frame F according to an embodiment of the present inventiondFIG. 6B is a schematic polarity diagram of the dot inversion driving performed by the medium-cholesterol liquid crystal pixel matrix Mat, in which the frame F shown in FIG. 6A is showndAdjacent frame AF ofdPolarity diagram of dot inversion driving of the medium-cholesterol liquid crystal pixel matrix Mat. As shown in FIG. 6A, the data driving signal Sig _ S1～Sig_SMThe adjacent cholesterol liquid crystal in the cholesterol liquid crystal pixel matrix MatThe pixels are driven by opposite polarity voltages, that is, each cholesteric liquid crystal pixel and the cholesteric liquid crystal pixels above, below, left and right are driven by opposite polarity voltages. In this case, in the same frame, the same cholesteric liquid crystal pixel receives the same data driving signal with the same polarity to achieve the dot inversion effect although the reset voltage and the determination voltage have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 6B, AF is performed in the adjacent framedIn the cholesteric liquid crystal pixel matrix Mat, each cholesteric liquid crystal pixel and the frame FdThe same polarity of the cholesteric liquid crystal pixels in two adjacent frames can be achieved by driving with the voltage with the opposite polarity.
It is noted that the present invention is not limited to the timing chart shown in fig. 3, and the scan lines G can be driven by a smaller determination voltage to achieve a stable planar state or focal conic state and corresponding gray scales and brightness after the cholesteric liquid crystal pixels are driven by a larger reset voltage to achieve a stable homeotropic alignment state1～GNAfter a proper number of groups, the active driving shown in fig. 3 is performed to increase the decision retention time and improve the display quality.
In detail, referring to fig. 7, fig. 7 shows a frame F according to an embodiment of the present invention2Middle gate driving signal Sig _ G1～Sig_GNTiming diagram of (2). As shown in fig. 7, the scanning line G1～GNFirstly, the scanning lines are divided into three groups of scanning lines G in proper number1～Gn、Gn+1～G2n、G 2n+1～GNGate driving signal Sig _ G corresponding to the first group1～Sig_GnFirstly, respectively aligning the corresponding scan lines G1～GnA reset scan is performed, in which case the data driving signal Sig _ S1～Sig_SMDriving the corresponding cholesteric liquid crystal pixels with a larger reset voltage, and waiting for a reset retention time Thr' to determine that all the cholesteric liquid crystal pixels in the first group reach a stable equidirectional arrangement state, and then generating a gate drive signal Sig _ G1～Sig_GnThen respectively corresponding to the corresponding scanning lines G1～GnTo carry outOne time of determining scanning, at the time of the data driving signal Sig _ S1～Sig_SMDriving the corresponding cholesteric liquid crystal pixels with a smaller determined voltage according to the picture desired by the user, and then all the cholesteric liquid crystal pixels in the first group can convert the frame F2The remaining time is used as the determination retention time Thd1And then respectively achieving a stable plane state or focal conic state and corresponding gray scale and brightness. And so on, all the cholesteric liquid crystal pixels in the second group and the third group can respectively convert the frame F2The remaining time and the time before the next frame is reset-scanned are used as the determination of the retention time Thd2、Thd3Then, a stable plane state or focal conic state and corresponding gray scale and brightness are achieved to display the picture desired by the user.
Specifically, the first group of scanning lines G is subjected to reset scanning1～GnThe reset scan times tsr of about 20 mus, respectively, may be turned on only at scan line G1～GnWhen the total number n is 600/3-200, the total reset scan time tsr n is about 4ms, and the scan line G is scanned when the decision scan is performed1～GnThe decision scan time tsd may be turned on only about 20 μ s each, the total decision scan time tsd n is also about 4ms, the reset hold time Thr' may be set to 1ms, and the frame F2With a length of 33ms, the remaining decision retention time Thr of the first group133-4-1-4 ═ 24ms (if scan line G is in progress)1～GNEqual four groups of pixels are 33-3-1-3 ═ 26ms), so that all the cholesteric liquid crystal pixels in the first group can reach stable plane state or focal conic state and corresponding gray scale and brightness. In three groups of scanning lines G1～Gn、Gn+1～G2n、G 2n+1～GNIn the case of scanning successively (fig. 7 shows a space between the first and second groups and a space between the second and third groups, but the invention is not limited thereto), all the cholesteric liquid crystal pixels in the second and third groups can respectively scan the frame F2The remaining time and the time before the next frame is reset-scanned are used as the determination of the retention time Thd2、Thd3And both are 24 ms. Thus, the present invention scans the scan line G1～GNThe active driving is performed after the appropriate number of groups, so as to increase the determined retention time Thd1、Thd2、Thd3The cholesteric liquid crystal pixel is ensured to reach a stable plane state or a focal conic state and corresponding gray scale and brightness so as to improve the display quality.
On the other hand, the present invention can also first scan the line G1～GNAfter the cholesterol liquid crystal pixels corresponding to a certain number of scanning lines are subjected to one reset scanning, the reset cholesterol liquid crystal pixels which reach a stable same-direction arrangement state and the rest non-reset cholesterol liquid crystal pixels which are not subjected to reset scanning are driven by corresponding determining voltages and reset voltages in an interlaced mode to carry out determining scanning and reset scanning, so that the determining retention time is prolonged, and the display quality is improved.
In detail, referring to fig. 8, fig. 8 shows a frame F according to an embodiment of the present invention3Middle gate driving signal Sig _ G1～Sig_GNTiming diagram of (2). As shown in FIG. 8, the gate driving signal Sig _ G1～Sig_Gn’Firstly, respectively aligning the corresponding scan lines G1～Gn’After a reset scan, the data driving signal Sig _ S is generated1～Sig_SMDriving the corresponding cholesteric liquid crystal pixel with a larger reset voltage, and then driving the gate with a gate driving signal Sig _ G1For the scanning line G1And performing a decision scan on the cholesteric liquid crystal pixels corresponding to the stable homodromous arrangement state, wherein the data driving signal Sig _ S1～Sig_SMDriving the corresponding cholesteric liquid crystal pixels with a smaller determined voltage according to the desired picture of the user, and then driving the gate with a gate driving signal Sig _ Gn’+1For the scanning line Gn’+1And performing a reset scan corresponding to the cholesterol liquid crystal pixels without reset scan. In this way, the cholesterol liquid crystal pixels which have reached the stable same-direction arrangement state and the cholesterol liquid crystal pixels which are not subjected to the reset scanning can be alternately subjected to the determination scanning and the reset scanning until the scanning line G1～GNAfter all the reset scans are completed, the gate driving signals Sig _ GN-n’+1～Sig_GNThen, the rest scanning lines G which are not subjected to determined scanning are scannedN-n’+1～GNAnd performing decision scanning corresponding to the cholesterol liquid crystal pixels. Therefore, the invention can select the corresponding scanning line G which is firstly subjected to one-time reset scanning1～Gn’When the corresponding cholesterol liquid crystal pixel after reset scanning reaches a stable same-direction arrangement state, the determining scanning and the reset scanning are carried out in a staggered mode, so that the determining retention time can be greatly increased, and the display quality is improved.
Specifically, the scanning line G is scanned when the reset scanning is performed1～Gn’The reset scan time tsr can be only about 20 μ s, and since the cholesteric liquid crystal pixels achieve a stable alignment state of about 3ms, if the scan line G is designed to be spaced apart from the two reset scans shown in fig. 81～Gn’The total number n 'is equal to 75, and the total reset scan time tsr 2 n' is about 3ms, so that the gate driving signal Sig _ G is generated1～Sig_Gn’Firstly, respectively aligning the corresponding scan lines G1～Gn’After a reset scan, scan line G1The corresponding cholesteric liquid crystal pixel reaches a stable alignment state after 3ms from the reset scanning, without the need of additionally increasing the reset retention time Thr (i.e. reaching a stable state when scanning other scanning lines) as shown in FIG. 3 or FIG. 7, at which time the gate driving signal Sig _ G1Can be aligned with the scanning line G1And performing a decision scan corresponding to the cholesteric liquid crystal pixels having reached a stable homodromous arrangement state, and then scanning lines G1Corresponding to the cholesteric liquid crystal pixel, frame F can be obtained3The remaining time is used as the retention time to reach the stable planar state or focal conic state and the corresponding gray scale and brightness, wherein the scanning line G1The retention time of the cholesteric liquid crystal pixel is about 30ms (33ms-3ms-20 μ s) and can be greatly increased. Therefore, the invention can select the corresponding scanning line G which is firstly subjected to one-time reset scanning1～Gn’When the reset scanning of the corresponding cholesterol liquid crystal pixel reaches a stable same-direction arrangement state, the determining scanning and the reset scanning are carried out in a staggered mode, so that the determining retention time can be greatly prolonged, and the display quality is improved.
It should be noted that the above-mentioned embodiments are only examples of the present invention, and those skilled in the art can make modifications or changes according to the embodiments without limitation. For example, the above embodiments are generally performed in a specific order during scanning, but other orders are also possible as long as the spirit of the present invention is met. In addition, whether there is a gap between two scans may be determined according to the requirement, and is not limited to the illustrated embodiment. The polarity inversion operation performed in fig. 4A to 6B can also be applied to the driving method in fig. 7 and 8, but is not limited to the driving method in fig. 3. In other words, although FIG. 7, FIG. 8 and FIG. 3 are for the scan line G1～GNThe reset scanning and the determining scanning performed by the corresponding cholesterol liquid crystal pixel are different in sequence, but the data driving signal Sig _ S1～Sig_SMWill correspond to the data line S1～SMThe polarity of the cholesteric liquid crystal pixel in (1) is the same as that in fig. 4A to 6B when the polarity is inverted.
In detail, as shown in fig. 4A, the data driving signal Sig _ S1～Sig_SMWill correspond to the data line S1～SMThe cholesterol liquid crystal pixels in the middle odd-numbered rows are driven by positive-polarity voltage, and the cholesterol liquid crystal pixels in the even-numbered rows are driven by negative-polarity voltage. In this case, in the same frame, the same cholesteric liquid crystal pixel receives the same data driving signal with the same polarity for the column inversion effect although the reset voltage and the determination voltage have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 4B, AF is performed in the adjacent framecMiddle, data driving signal Sig _ S1～Sig_SMWill correspond to the data line S1～SMThe cholesterol liquid crystal pixels in the odd-numbered rows are driven by negative voltage and the cholesterol liquid crystal pixels in the even-numbered rows are driven by positive voltage, so that the effect of polarity inversion of the same cholesterol liquid crystal pixels in two adjacent frames can be achieved.
On the other hand, as shown in fig. 5A, the data driving signal Sig _ S1～Sig_SMWill correspond to the scanning line G1～GNGallbladder fixed in middle and odd rowsThe lc pixels are driven with a positive polarity voltage and the cholesteric liquid crystal pixels in the even-numbered rows are driven with a negative polarity voltage. In this case, in the same frame, the same cholesteric liquid crystal pixels receive the same polarity of the corresponding data driving signals with the same polarity for the row inversion effect, although the reset voltages and the determination voltages have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 5B, AF is performed in the adjacent framerMiddle, data driving signal Sig _ S1～Sig_SMWill correspond to the scanning line G1～GNThe cholesterol liquid crystal pixels in the odd-numbered rows are driven by negative voltage, and the cholesterol liquid crystal pixels in the even-numbered rows are driven by positive voltage, so that the effect of polarity inversion of the same cholesterol liquid crystal pixels in two adjacent frames can be achieved.
On the other hand, as shown in fig. 6A, the data driving signal Sig _ S1～Sig_SMThe adjacent cholesteric liquid crystal pixels in the cholesteric liquid crystal pixel matrix Mat are driven by opposite polarity voltages, that is, each cholesteric liquid crystal pixel and the cholesteric liquid crystal pixels above, below, left and right are driven by opposite polarity voltages. In this case, in the same frame, the same cholesteric liquid crystal pixel receives the same data driving signal with the same polarity to achieve the dot inversion effect although the reset voltage and the determination voltage have different magnitudes during the reset scan time tsr and the determination scan time tsd. Further, as shown in FIG. 6B, AF is performed in the adjacent framedIn the cholesteric liquid crystal pixel matrix Mat, each cholesteric liquid crystal pixel and the frame FdThe same polarity of the cholesteric liquid crystal pixels in two adjacent frames can be achieved by driving with the voltage with the opposite polarity.
Therefore, the driving operation of the driving module 12 can be summarized as a driving flow 90, as shown in fig. 9, which includes the following steps:
step 900: and starting.
Step 902: generating a gate driving signal Sig _ G1～Sig_GN。
Step 904: generating a data drive signal Sig _ S1～Sig_SM。
Step 906: control ofGate driving signal Sig _ G1～Sig_GNAnd data driving signal Sig _ S1～Sig_SMTherefore, the plurality of cholesteric liquid crystal pixels in the active matrix driving cholesteric liquid crystal display device 10 are driven by the reset voltage to reach a stable equidirectional arrangement state, and then are driven by the plurality of corresponding determination voltages respectively to reach a stable plane state or a focal conic state.
Step 908: and (6) ending.
The detailed operation of the driving process 90 can refer to the related description of the driving module 12, and is not described herein again.
In summary, the present invention drives the cholesteric liquid crystal pixels to achieve a stable homeotropic alignment state by a larger reset voltage, and then actively drives the cholesteric liquid crystal pixel matrix Mat by a smaller determination voltage to achieve a stable planar state or a focal conic state and corresponding gray scales and brightness, so that the present invention has a fast refresh rate and can smoothly perform image display such as film playing. In addition, the invention performs polarity inversion driving, thereby avoiding permanent damage caused by polarization of liquid crystal material and image residual effect. Furthermore, the present invention is provided by scanning the line G1～GNAfter grouping, respectively performing active driving, or properly selecting the corresponding scan line G for performing a reset scan1～Gn’The number of the first and second sub-pixels is determined by the number of the first sub-pixels, and the determination scanning and the reset scanning are performed alternately, so that the determination retention time can be prolonged, and the display quality can be improved.
The above-mentioned embodiments are merely preferred embodiments of the present invention, and all equivalent changes and modifications made by the claims of the present invention should be covered by the scope of the present invention.
[ notation ] to show
10 active matrix driving cholesterol liquid crystal display device
12 drive module
100 source electrode driving circuit
102 gate driving circuit
104 time sequence controller
S1～SMData line
G1～GNScanning line
Mat cholesterol liquid crystal pixel matrix
T is transistor
Cst storage capacitor
Cls liquid crystal capacitor
Vcom common voltage
Hsync horizontal synchronization signal
Ena output enable signal
Sig_S1～Sig_SMData driving signal
Sig_G1～Sig_GNA gate driving signal
F1,Fc,AFc,Fr,AFr,Fd,AFd,F2,F3:Frame
tsr reset scan time
Thr reset retention time
tsd-determining the scanning time
Thd,Thd1Determining the retention time
90, the process is
900 to 908.

Claims (26)

1. A driving module for an active matrix driving cholesteric liquid crystal display device, comprising:
a gate driving circuit for generating a plurality of gate driving signals;
a source driving circuit for generating a plurality of data driving signals; and
the time schedule controller is used for controlling the plurality of gate driving signals and the plurality of data driving signals, so that a plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by reset voltage to reach a stable homodromous arrangement state (Homeotropic) and then are driven by a plurality of corresponding determining voltages respectively to reach a stable plane state (Planar) or a Focal-conic state (Focal-conic).
2. The driving module of claim 1, wherein the reset voltage is greater than the plurality of corresponding decision voltages.
3. The driving module of claim 1, wherein the plurality of cholesteric liquid crystal pixels are all driven by the reset voltage respectively, and after the stable homeotropic alignment state is achieved, the plurality of cholesteric liquid crystal pixels are driven by the plurality of corresponding determining voltages respectively, so as to achieve the stable planar state or the focal conic state.
4. The driving module of claim 3, wherein the cholesteric liquid crystal pixels are driven by the reset voltage and then wait for a first reset retention time to achieve a stable homeotropic alignment.
5. The driving module of claim 1, wherein the timing controller controls the plurality of gate driving signals and the plurality of data driving signals to perform a polarity inversion operation.
6. The driving module of claim 5, wherein the polarity inversion operation performs Column inversion (Column inversion), Row inversion (Row inversion) or Dot inversion (Dot inversion) in the same frame (frame).
7. The driving module of claim 5, wherein the polarity inversion operation drives the cholesteric liquid crystal pixels with different polarities for each of the cholesteric liquid crystal pixels in the plurality of cholesteric liquid crystal pixels in adjacent frames.
8. The driving module as claimed in claim 1, wherein all of the first cholesteric liquid crystal pixels corresponding to a first group of scan lines of the plurality of groups of scan lines of the active matrix driving cholesteric liquid crystal display device are driven by the reset voltage, respectively, and after the stable homeotropic alignment state is achieved, the first cholesteric liquid crystal pixels are driven by a plurality of first corresponding decision voltages of the plurality of corresponding decision voltages, respectively, so as to achieve the stable planar state or the focal conic state.
9. The driving module of claim 8, wherein all of the first cholesteric liquid crystal pixels are driven by the reset voltage before waiting for a second reset retention time to achieve a stable homeotropic alignment.
10. The driving module as claimed in claim 8, wherein after the first cholesteric liquid crystal pixels are driven by the first corresponding determining voltages, the second cholesteric liquid crystal pixels corresponding to the second group of the plurality of scan lines are driven by the reset voltage to reach the stable alignment state, and then the second cholesteric liquid crystal pixels are driven by the second corresponding determining voltages to reach the stable planar state or the focal conic state.
11. The driving module of claim 10, wherein the second cholesteric liquid crystal pixels are driven by the reset voltage for a third reset retention time to achieve a stable homeotropic alignment.
12. The driving module as claimed in claim 1, wherein the specific cholesteric liquid crystal pixels corresponding to a specific number of scan lines in the plurality of scan lines in the active matrix cholesteric liquid crystal display device are all driven by the reset voltage respectively, and after the stable homeotropic alignment state is achieved, the specific corresponding determination voltages of the corresponding determination voltages and the reset voltage are alternatively used for driving the reset cholesteric liquid crystal pixels which have achieved the stable homeotropic alignment state and the non-reset cholesteric liquid crystal pixels which are not driven by the reset voltage.
13. The driving module of claim 12, wherein after all of the plurality of cholesteric liquid crystal pixels are driven by the reset voltage, the remaining corresponding determination voltages are used to drive a plurality of pending cholesteric liquid crystal pixels that are not driven by a plurality of remaining corresponding determination voltages.
14. A driving method for an active matrix driving cholesteric liquid crystal display device, comprising:
generating a plurality of gate driving signals;
generating a plurality of data driving signals; and
the plurality of gate driving signals and the plurality of data driving signals are controlled, so that a plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by reset voltage firstly, and are driven by a plurality of corresponding determining voltages respectively after reaching a stable equidirectional arrangement state, so as to reach a stable plane state or a focal conic state.
15. The driving method of claim 14, wherein the reset voltage is greater than the plurality of corresponding determination voltages.
16. The driving method as claimed in claim 14, wherein the step of controlling the plurality of gate driving signals and the plurality of data driving signals such that the plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by the reset voltage to reach the stable homeotropic alignment state and then driven by the plurality of corresponding decision voltages respectively to reach the stable planar state or the stable focal conic state comprises:
the plurality of cholesteric liquid crystal pixels are all driven by the reset voltage respectively, and after the stable equidirectional arrangement state is achieved, the plurality of cholesteric liquid crystal pixels are driven by the plurality of corresponding determining voltages respectively, so that the stable plane state or the stable focal conic state is achieved.
17. The method as claimed in claim 16, further comprising waiting for a first reset hold time after all the cholesteric liquid crystal pixels are driven by the reset voltage to achieve a stable homeotropic alignment.
18. The driving method as claimed in claim 14, further comprising controlling the plurality of gate driving signals and the plurality of data driving signals to perform a polarity inversion operation.
19. The driving method of claim 18, wherein the polarity inversion operation performs Column inversion (Column inversion), Row inversion (Row inversion) or Dot inversion (Dot inversion) in the same frame (frame).
20. The driving method as claimed in claim 18, wherein the polarity inversion operation drives the cholesteric liquid crystal pixels with different polarities for each of the plurality of cholesteric liquid crystal pixels in adjacent frames.
21. The driving method as claimed in claim 14, wherein the step of controlling the plurality of gate driving signals and the plurality of data driving signals such that the plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by the reset voltage to reach the stable homeotropic alignment state and then driven by the plurality of corresponding decision voltages respectively to reach the stable planar state or the stable focal conic state comprises:
the active matrix driving cholesterol liquid crystal display device comprises a plurality of first cholesterol liquid crystal pixels, a plurality of second cholesterol liquid crystal pixels and a plurality of third cholesterol liquid crystal pixels, wherein the plurality of first cholesterol liquid crystal pixels are respectively driven by the reset voltage firstly, and after the plurality of first cholesterol liquid crystal pixels are driven by the reset voltage to reach a stable same-direction arrangement state, the plurality of first cholesterol liquid crystal pixels are respectively driven by a plurality of first corresponding decision voltages in the plurality of corresponding decision voltages to reach a stable plane state or a focal conic state.
22. The method as claimed in claim 21, further comprising waiting for a second reset hold time after all the first cholesteric liquid crystal pixels are driven by the reset voltage to reach a stable homeotropic alignment state.
23. The driving method as claimed in claim 21, further comprising driving the plurality of first cholesteric liquid crystal pixels by the plurality of first corresponding determining voltages, respectively, driving all of the plurality of second cholesteric liquid crystal pixels corresponding to a second group of the plurality of groups of scan lines by the reset voltage to achieve a stable alignment state, and driving the plurality of second cholesteric liquid crystal pixels by a plurality of second corresponding determining voltages, respectively, to achieve a stable planar state or a stable focal conic state.
24. The method as claimed in claim 23, further comprising waiting for a third reset hold time after all of the second cholesteric liquid crystal pixels are driven by the reset voltage to achieve a stable homeotropic alignment.
25. The driving method as claimed in claim 14, wherein the step of controlling the plurality of gate driving signals and the plurality of data driving signals such that the plurality of cholesteric liquid crystal pixels in the active matrix driven cholesteric liquid crystal display device are driven by the reset voltage to reach the stable homeotropic alignment state and then driven by the plurality of corresponding decision voltages respectively to reach the stable planar state or the stable focal conic state comprises:
the active matrix driving cholesterol liquid crystal display device comprises a plurality of specific cholesterol liquid crystal pixels, a plurality of reset voltage-driven pixel groups and a plurality of non-reset cholesterol liquid crystal pixel groups, wherein the specific cholesterol liquid crystal pixels corresponding to a specific number of scanning lines in a plurality of groups of scanning lines in the active matrix driving cholesterol liquid crystal display device are all driven by the reset voltage respectively, and after the stable same-direction arrangement state is achieved, the specific cholesterol liquid crystal pixels which reach the stable same-direction arrangement state and the non-reset cholesterol liquid crystal pixels which are not driven by the reset voltage are driven by a plurality of specific corresponding determination voltages in the corresponding determination voltages and the reset voltage in a staggered mode.
26. The method as claimed in claim 25, further comprising driving a plurality of pending cholesteric liquid crystal pixels not driven by a plurality of remaining corresponding determining voltages among the plurality of corresponding determining voltages with the plurality of remaining corresponding determining voltages after all of the plurality of cholesteric liquid crystal pixels are driven by the reset voltage.
CN202010499426.1A 2020-05-14 2020-06-04 Driving module for active matrix driving cholesterol liquid crystal display device and driving method thereof Pending CN113674709A (en)

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