Active-type cholesteric liquid crystal display module and active-type cholesteric liquid crystal display device

Abstract

An active cholesteric liquid crystal display module and an active cholesteric liquid crystal display device are provided. [Solution] The data electrode layer 140 and the scan electrode layer 120 respectively include M data electrode lines and N scan electrode lines, whose projections are perpendicular to each other, forming M*N projection intersections. The TFT element layer 170 includes M*N TFT elements, each with its source electrode connected to a data electrode line and its gate electrode connected to a scan electrode line. The common ground electrode layer 180 includes N common ground electrode lines. The cholesteric liquid crystal layer 130 includes M*N liquid crystal pixel regions, each with one end connected to a common ground electrode line and the other end connected to the drain electrode of the TFT element. When the scan electrode line corresponding to a liquid crystal pixel region is conductive, the common ground electrode line and the data electrode line are simultaneously conductive.

Description

[Technical Field]

[0001] The present invention relates to liquid crystal display technology, and more particularly to driving technology for cholesteric liquid crystals. [Background technology]

[0002] Cholesteric liquid crystals are one of the main technologies used in e-book displays. Liquid crystal molecules possess bi-stable display properties, which contribute to power saving. The bi-stable property of cholesteric liquid crystal molecules means that they naturally exist in two stable states: a planar state and a focal-conic state. In the planar state, the liquid crystals are arranged in an orderly fashion and can reflect light of specific wavelengths, commonly referred to as the bright state. In the focal-conic state, the liquid crystals are arranged in a disorderly fashion, transmitting or scattering incident light and rarely reflecting it, commonly referred to as the dark state. Only during transitions (from the planar state to the focal-conic state or vice versa) is electricity required; when the screen is static, almost no power is consumed, resulting in excellent power saving.

[0003] When cholesteric liquid crystal molecules transition, a transition voltage must be applied via a driving IC. Based on the driving method, they can be classified as passive driving or active driving. Passive cholesteric liquid crystal display modules use a passive matrix driving method, which means that each pixel does not have an individual switch control component; instead, pixels are controlled through a matrix formed by crossing row and column electrodes. The state of the liquid crystal molecules is controlled by changing the voltage at the intersection of rows and columns. This system allows multiple pixels to share a single command system. Active cholesteric liquid crystal display modules use an active matrix driving method, which uses an independent switch control component for each cholesteric liquid crystal pixel. The switch components precisely control the state of the cholesteric liquid crystal molecules in each pixel, allowing for fast and accurate updates of the display content. This system is as if each pixel had its own dedicated commander.

[0004] In terms of speed, passive cholesteric liquid crystals require scanning the entire matrix to control the pixels, resulting in slower signal transmission and a slower response time for the cholesteric liquid crystal molecules, making them more susceptible to afterimages and blurring when displaying dynamic images. Active cholesteric liquid crystals allow each pixel to be controlled independently, resulting in faster signal transmission and response times and allowing the cholesteric liquid crystal molecules to switch states more quickly. When displaying dynamic images, the image update speed is fast and afterimages are less noticeable. For example, when displaying fast-moving video or animation, each frame can be displayed clearly.

[0005] In terms of display quality, passive cholesteric LCDs are relatively inferior in terms of contrast, color expression, and grayscale gradation due to limitations in their driving method, and may suffer from problems such as insufficient color vividness and poor image gradation, resulting in relatively low display quality.Active cholesteric LCDs can precisely control the brightness and color of each pixel, thereby achieving higher contrast, richer color expression, and finer grayscale gradation, making images appear more vivid and realistic, and the color transitions more natural.

[0006] In terms of cost, the manufacturing process of passive cholesteric liquid crystal is relatively simple and does not require complex control components to be installed at each pixel, resulting in lower costs.However, the manufacturing process of active cholesteric liquid crystal is complex and requires the integration of switching components at each pixel, which places high demands on process precision, resulting in higher manufacturing costs.

[0007] In terms of power consumption, passive cholesteric liquid crystals have bi-stable properties, and when the screen is static, they can maintain a display state without continuous power supply, consuming almost no power, resulting in very low power consumption when displaying static content.When active cholesteric liquid crystals display a static screen, the switching components of each pixel must maintain a constant voltage state to maintain the display, consuming a certain amount of power, resulting in relatively higher power consumption.

[0008] Regarding the prior art of active cholesteric liquid crystals, Patent Publication No. TW202142938A discloses a driving module for use in an active matrix cholesteric 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 to generate a plurality of gate driving signals. The source driving circuit is used to generate a plurality of data driving signals. The timing controller is used to control 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 cholesteric liquid crystal display device are first driven with a reset voltage to reach a stable unidirectional alignment state, and then driven with corresponding decision voltages to reach a stable planar state or a stable conical state.

[0009] In the prior art, Patent Publication No. CN113971941A discloses a driving module for an active matrix cholesteric liquid crystal display device, which includes 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 a timing controller for controlling the gate driving signals and the data driving signals, and modulating an array common voltage at the end of a storage capacitor to generate a boost voltage at the other end of the storage capacitor through capacitor coupling, whereby a pixel voltage is used to drive a plurality of cholesteric liquid crystal pixels, and the pixel voltage is the sum of the driving voltage of a corresponding driving signal among the plurality of data driving signals and the boost voltage.

[0010] Cholesteric liquid crystal displays use active driving. When updating pixels, whether through PWM (Pulse Width Modulation) or DDS (Dynamic Drive Scheme), a switching component applies a specific transition voltage to reset the liquid crystal state at the original pixel position, causing the cholesteric liquid crystal to enter a transparent state. Then, by applying an appropriate transition voltage through the switching component, the cholesteric liquid crystal assumes the desired grayscale reflective state. Because the transition voltage required to reset the liquid crystal state is very high, a specialized liquid crystal driver IC capable of providing a sufficiently high transition voltage is required. The manufacturing cost of such specialized liquid crystal driver ICs is extremely high, several times higher than that of standard liquid crystal driver ICs. As the number of pixels and size of a display device increase, more driver ICs are required, significantly increasing manufacturing costs and hindering the widespread adoption and application of the technology. Therefore, further improvement was needed. Summary of the Invention [Problem to be solved by the invention]

[0011] In order to solve the problem of the prior art active cholesteric liquid crystal requiring a high voltage to drive an IC, the present invention aims to provide an active cholesteric liquid crystal display module that can meet the active driving needs without using a special liquid crystal driving IC, by applying a common ground voltage to the common ground electrode, thereby reducing the data voltage required for the transition of the cholesteric liquid crystal. This also significantly reduces the cost of components required during manufacturing.

[0012] To achieve the objectives of the present invention, a first best embodiment of the present invention provides an active-type cholesteric liquid crystal display module, which includes a liquid crystal driving unit, a TFT element layer, a first substrate, a second substrate, and a scan electrode layer, a data electrode layer, a cholesteric liquid crystal layer, and a common ground electrode layer disposed between the first substrate and the second substrate. The data electrode layer is located near the first substrate and includes M data electrode lines arranged in parallel, where M is an integer greater than 1. The scan electrode layer is also located near the first substrate and includes N scan electrode lines arranged in parallel, where N is an integer greater than 1. The horizontal projections of the scan electrode lines and the data electrode lines are perpendicular to each other, thereby forming M*N projection intersections.

[0013] The TFT element layer is also adjacent to the first substrate and includes M*N TFT elements used as switching components. Each TFT element corresponds to a projection intersection. The source electrode of each TFT element is connected to the data electrode line corresponding to the vertical intersection, and its gate electrode is connected to the scan electrode line corresponding to the projection intersection. The common ground electrode layer is adjacent to the second substrate and includes N common ground electrode lines and is parallel to the N scan electrode lines.

[0014] A cholesteric liquid crystal layer is disposed between the common ground electrode layer and the TFT element layer, and includes M*N liquid crystal pixel areas, each of which corresponds to a projection intersection point, and one end of each liquid crystal pixel area is connected to a common ground electrode line and the other end is connected to the drain electrode of a TFT element.

[0015] The liquid crystal driving unit includes at least one scan driving IC, at least one data driving IC, and at least one common ground driving IC. The scan driving IC is used to apply a scan voltage Vscan to each scan electrode line, the data driving IC is used to apply a data voltage Vdata to each data electrode line, and the common ground driving IC is used to apply a common ground voltage Vcom to each common ground electrode line. When the liquid crystal driving unit makes the scan electrode line corresponding to one liquid crystal pixel area conductive, the common ground electrode line and data electrode line connected to the liquid crystal pixel area are simultaneously made conductive, and the voltage polarity of the common ground voltage Vcom is opposite to that of the data voltage Vdata, so that the data voltage Vdata and the common ground voltage Vcom together form a cholesteric liquid crystal transition voltage.

[0016] In conventional technology, no voltage is applied to the common ground electrode line, and it is only used as ground. Therefore, when the cholesteric liquid crystal transitions, the data electrode lines must provide all the high voltage necessary for the liquid crystal to transition, requiring a special liquid crystal driving IC. In this embodiment, a common ground voltage Vcom, which has the opposite polarity to the data voltage Vdata, is applied through the common ground electrode line, and the two voltages, the common ground voltage Vcom and the data voltage Vdata, together form the cholesteric liquid crystal transition voltage. Because both the common ground electrode line and the data electrode line can be driven using a standard driving IC, there is no need for a special driving IC, which effectively reduces component costs.

[0017] Based on the same technical idea, the present invention also provides a second best embodiment of an active cholesteric liquid crystal display device that provides a monochrome screen display, which includes one active cholesteric liquid crystal display module as described in the first best embodiment, one control module, and one power module that provides power to the control module. The control module is further connected to the liquid crystal driving unit of the active cholesteric liquid crystal display module, and provides the controls required by the scan driving IC, data driving IC, and common ground driving IC.

[0018] Based on the same technical idea, the third best embodiment of the present invention provides an active cholesteric liquid crystal display device for multi-color or split-screen display, which includes a plurality of active cholesteric liquid crystal display modules as described in the first best embodiment, a control module, and a power module for providing power to the control module. The control module is further connected to the liquid crystal driving unit of each active cholesteric liquid crystal display module, and provides the control required by the scan driving IC, data driving IC, and common ground driving IC.

[0019] In the second and third embodiments, a common ground voltage Vcom having the opposite polarity to the data voltage Vdata is applied through the common ground electrode line, and the common ground voltage Vcom and the data voltage Vdata together form a cholesteric liquid crystal transition voltage. Both the common ground electrode line and the data electrode line can be driven using a standard driving IC, eliminating the need for a special driving IC and effectively reducing component costs. [Effects of the Invention]

[0020] The common ground electrode line of the present invention applies a common ground voltage Vcom, which has the opposite polarity to the data voltage Vdata, and the common ground voltage Vcom and the data voltage Vdata together form a cholesteric liquid crystal transition voltage. Both the common ground electrode line and the data electrode line can be driven by a standard driving IC, eliminating the need for a special driving IC and effectively reducing component costs. [Brief explanation of the drawings]

[0021] The drawings provided are for the purpose of providing a better understanding of the embodiments of the present invention, showing the embodiments of the present invention and explaining the principles of the present invention together with the text. The drawings below do not limit the implementation of the present invention, and those skilled in the art can derive other drawings based on these drawings without any creative effort. [Figure 1] 1 is a schematic diagram of the structure of an active cholesteric liquid crystal display module according to a first preferred embodiment of the present invention; [Figure 2A] 1 is a circuit diagram of an active cholesteric liquid crystal display module according to a first preferred embodiment of the present invention; [Figure 2B] 1 is a circuit diagram of an active cholesteric liquid crystal display module according to a first preferred embodiment of the present invention; [Figure 2C] 1 is a circuit diagram of an active cholesteric liquid crystal display module according to a first preferred embodiment of the present invention; [Figure 3] 1 is a prior art schematic diagram of a PWM driven active cholesteric liquid crystal display module; [Figure 4] 3 is a schematic diagram of a voltage sequence of an active-type cholesteric liquid crystal display module driven by PWM according to the present invention; [Figure 5] 2 is a schematic diagram of an active-type cholesteric liquid crystal display device according to a second preferred embodiment of the present invention; [Figure 6A] 3 is a schematic diagram of an active-type cholesteric liquid crystal display device according to a third preferred embodiment of the present invention; [Figure 6B] 3 is a schematic diagram of an active-type cholesteric liquid crystal display device according to a third preferred embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0022] The structure, features and effects of the present invention will be described in detail below with reference to the best embodiment and drawings.

[0023] The specific structural and functional details disclosed in the present invention are merely representative and are used to explain the embodiments of the present invention, and the present invention can be embodied in various modified forms and is not limited to the embodiments disclosed herein.

[0024] Terms used in this invention, such as "center," "lateral," "up," "down," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside," indicating directions or positional relationships, are based on the directions or positional relationships shown in the drawings. Except where the applicant specifically emphasizes or limits the role of a function, these terms are used merely for the convenience of describing this invention and are not intended to indicate or suggest a specific orientation or specific directional structure and operation of a specified device or component. Furthermore, terms such as "first" and "second" are used for descriptive purposes only and do not indicate relative importance. Unless otherwise clearly indicated by the context, the terms "one" and "item" in this invention also include the plural.

[0025] Unless otherwise expressly specified or limited, the terms "attached," "adjacent," and "connected" in this invention shall be interpreted broadly. For example, a fixed connection may be a detachable connection or a connection formed by integral molding, and may be interpreted broadly to mean a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, or communication between the interiors of two components. A person skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. [Example]

[0026] The first best embodiment of the present invention is an active-type cholesteric liquid crystal display module 10. As shown in Figure 1, it includes a liquid crystal driving unit 160, a TFT element layer 170, a first substrate 110, a second substrate 150, and a scan electrode layer 120, a data electrode layer 140, a cholesteric liquid crystal layer 130, and a common ground electrode layer 180 disposed between the first substrate 110 and the second substrate 150. The data electrode layer 140 and the scan electrode layer 120 are both located near the first substrate 110, and the common ground electrode layer 180 is located near the second substrate 150.

[0027] 2A and 2B, the data electrode layer 140 includes M data electrode lines 141 arranged in parallel, and the scan electrode layer 120 includes N scan electrode lines 121 arranged in parallel. M and N are both integers greater than one. The horizontal projections of the scan electrode lines 121 and the data electrode lines 141 are perpendicular to each other, thereby forming M*N projection intersections. The common ground electrode layer 180 includes N common ground electrode lines 181, which are parallel to the N scan electrode lines 121. The horizontal projections of the common ground electrode lines 181 and the data electrode lines 141 are also perpendicular to each other, thus forming M*N projection intersections. Taking a screen with a resolution of 1024*768 as an example, M=1024 and N=768, meaning that there are 1024 data electrode lines 141, 768 scan electrode lines 121, and 768 common ground electrode lines 181.

[0028] As shown in Figure 1, the TFT element layer 170 is also close to the first substrate 110. As shown in Figures 2A to 2C, the TFT element layer 170 includes M*N TFT elements 171, which function as switching components in the present invention. Each TFT element 171 corresponds to the projected intersection of one scan electrode line 121 and one data electrode line 141, and also corresponds to the projected intersection of one common ground electrode line 181 and one data electrode line 141. For each TFT element 171, its source electrode is connected to the data electrode line 141 corresponding to the vertical intersection, and its gate electrode is connected to the scan electrode line 121 corresponding to the projected intersection.

[0029] 1, the cholesteric liquid crystal layer 130 is disposed between the common ground electrode layer 180 and the TFT element layer 170. As shown in FIGS. 2A and 2B, the cholesteric liquid crystal layer 130 includes M*N liquid crystal pixel regions 131, each corresponding to a projection intersection, and one end of each liquid crystal pixel region 131 is connected to a common ground electrode line 181 and the other end is connected to the drain electrode of a TFT element 171.

[0030] 2B , the liquid crystal driving unit 160 includes at least one scan driving IC 161, at least one data driving IC 162, and at least one common ground driving IC 163. The scan driving IC 161 is used to apply a scan voltage Vscan to each scan electrode line 121, the data driving IC 162 is used to apply a data voltage Vdata to each data electrode line 141, and the common ground driving IC 163 is used to apply a common ground voltage Vcom to each common ground electrode line 181. The numbers of scan driving ICs 161, data driving ICs 162, and common ground driving ICs 163 are mainly determined based on the size and number of pixels of the active-type cholesteric liquid crystal display module 10. If the size of the active-type cholesteric liquid crystal display module 10 is smaller and the number of pixels is fewer, fewer scan driving ICs 161, data driving ICs 162, and common ground driving ICs 163 can be used. When the size of the active type cholesteric liquid crystal display module 10 is larger and the number of pixels is larger, the number of scan driving ICs 161, data driving ICs 162 and common ground driving ICs 163 is larger.

[0031] 2C, when one liquid crystal pixel region 131 of the present invention performs a screen update, the liquid crystal driving unit 160 turns on the scan electrode line 121 corresponding to the liquid crystal pixel region 131, and the scan electrode line 121 outputs a scan voltage Vscan. Then, the common ground electrode line 181 and the data electrode line 141 connected to the liquid crystal pixel region 131 are simultaneously turned on to output a common ground voltage Vcom and a data voltage Vdata to the liquid crystal pixel region, respectively. The polarity of the common ground voltage Vcom is opposite to that of the data voltage Vdata, so that the data voltage Vdata and the common ground voltage Vcom together form a cholesteric liquid crystal transition voltage Vls.

[0032] More preferably, the data voltage Vdata is in the range of 0V to ±20V, and the common ground voltage Vcom is in the range of 0V to ±25V. In other words, when the data voltage Vdata is in the range of 0V to +20V, the common ground voltage Vcom should be in the range of 0V to -25V. If the data voltage Vdata is in the range of 0V to -20V, the common ground voltage Vcom should be in the range of 0V to +25V. The transition voltage Vlc of the liquid crystal formed by this combination can reach ±45V, and this can be achieved without a special driver IC.

[0033] As shown in FIG. 4 and FIG. 3, the voltage sequence diagrams will be used below to further explain the features of the present invention in comparison with the prior art.

[0034] Figure 3 shows a schematic diagram of the voltage sequence of a conventional PWM-driven active cholesteric liquid crystal display module. T1 is the time required for applying a data voltage to reset the liquid crystal transition, T2 is the response time for the liquid crystal itself, and T3 is the time required for applying a data voltage to cause the liquid crystal to transition to a specified reflectance. To update the screen of a certain liquid crystal pixel region 11, the scan electrode line 121 corresponding to the liquid crystal pixel region 11 is turned on to output a scan voltage Vscan1, and then the liquid crystal pixel region 11 turns on its corresponding data electrode line. During the T1 period, a data voltage Vdata1 is applied to the liquid crystal pixel region 11 with an alternating positive-negative pulse waveform to reset the screen of the liquid crystal pixel region 11. Then, during the T3 period, the data electrode line again applies a data voltage Vdata1 required for the new screen to the liquid crystal pixel region 11 with an alternating positive-negative pulse waveform, thereby accurately writing the grayscale data of the new screen to the liquid crystal. Then, the scan electrode lines corresponding to the liquid crystal pixel region 11 output a negative cutoff voltage, closing the liquid crystal pixel region 11 and waiting for the liquid crystal pixel region 11 to respond and form a new grayscale image. Next, the image is updated for the liquid crystal pixel region 21. At this time, the scan electrode lines corresponding to the liquid crystal pixel region 21 are turned on to output the scan voltage Vscan1, and then the data electrode lines corresponding to the liquid crystal pixel region 21 are turned on. During the T1 period, a data voltage Vdata2 is applied to the liquid crystal pixel region 21 with an alternating positive and negative pulse waveform to reset the image of the liquid crystal pixel region 21. During the T3 period, the data electrode lines again apply the data voltage Vdata2 required for the new image to the liquid crystal pixel region 21 with an alternating positive and negative pulse waveform to accurately write the grayscale data of the new image to the liquid crystal. Then, the scan electrode lines corresponding to the liquid crystal pixel region 21 output a negative cutoff voltage, closing the liquid crystal pixel region 21 and waiting for the liquid crystal pixel region 21 to respond and form a new grayscale image. Subsequently, the screen is updated for other liquid crystal pixel areas.

[0035] As shown in FIG. 3, in either the liquid crystal pixel region 11 or the liquid crystal pixel region 21, the screen update voltages Vlc11 and Vlc21 are both provided by the data voltages Vdata1 and Vdata2 output by the data electrode lines. During the T1 period, the required reset voltage is very high, so a special data driver IC is required to supply sufficient reset voltage.

[0036] Referring also to FIG. 2, FIG. 4 shows a schematic diagram of the voltage sequence of the PWM-driven active cholesteric liquid crystal display module of the present invention. T1 is the time it takes for the liquid crystal to reset after the application of the data voltage, T2 is the response time of the liquid crystal itself, and T3 is the time it takes for the liquid crystal to transition to the specified reflectance after the application of the data voltage. T4 is the response time of the liquid crystal itself. When simultaneously updating the screens of the liquid crystal pixel areas 131(11) and 131(21), the scan electrode line 121(1) corresponding to the liquid crystal pixel area 131(11) is turned on to output the scan voltage Vscan1. Subsequently, during the T1 period, the data electrode lines 141(1) and 141(2) corresponding to the liquid crystal pixel areas 131(11) and 131(21) are turned on to apply data voltages Vdata1 and Vdata2 to the liquid crystal pixel areas 131(11) and 131(21), respectively, with alternating positive and negative pulse waveforms. At the same time, the common ground electrode line 181(1) corresponding to the liquid crystal pixel areas 131(11) and 131(21) is also turned on, and a common ground voltage Vcom1 with an alternating positive and negative pulse waveform and opposite voltage polarity is applied to the liquid crystal pixel areas 131(11) and 131(21). The data voltage Vdata1 and the common ground voltage Vcom1 are combined to form a screen update voltage Vlc11, which resets the screen of the liquid crystal pixel area 131(11). At the same time, the data voltage Vdata2 and the common ground voltage Vcom1 are combined to form a screen update voltage Vlc21, which resets the screen of the liquid crystal pixel area 131(21).

[0037] During the T2 period, the data electrode lines 141(1) and 141(2) do not output data voltages, and the common ground electrode line 181(1) also does not output a common ground voltage. Then, during the T3 period, the data electrode lines 141(1) and 141(2) again apply appropriate data voltages Vdata1 and Vdata2 with alternating positive and negative pulse waveforms to the liquid crystal pixel areas 131(11) and 131(21). At the same time, the common ground electrode line 181(1) also applies a common ground voltage Vcom1 with an alternating positive and negative pulse waveform and opposite voltage polarity to the liquid crystal pixel areas 131(11) and 131(21). The data voltage Vdata1 and the common ground voltage Vcom1 are combined to form the screen update voltage Vlc11, which accurately writes the new grayscale data to the liquid crystal pixel area 131(11). At the same time, the data voltage Vdata2 and the common ground voltage Vcom1 are combined to form the screen update voltage Vlc21, which accurately writes the gray scale data of the new screen into the liquid crystal pixel region 131(21).

[0038] Finally, during the T4 period, the scan electrode line 121(1) outputs a negative cutoff voltage, closes the liquid crystal pixel areas 131(11) and 131(21), and waits for the liquid crystal response of the liquid crystal pixel areas 131(11) and 131(21) to complete the corresponding new gray scale screen, and then the screen update is completed.

[0039] Next, the screen is updated for the liquid crystal pixel areas 131(12) and 131(22). At this time, the scan electrode line 121(2) corresponding to the liquid crystal pixel areas 131(12) and 131(22) is turned on to output the scan voltage Vscan2. Next, during the T1 period, the data electrode lines 141(1) and 141(2) corresponding to the liquid crystal pixel areas 131(12) and 131(22) are turned on to apply data voltages Vdata1 and Vdata2 with alternating positive and negative pulse waveforms to the liquid crystal pixel areas 131(12) and 131(22). At the same time, the common ground electrode line 181(2) corresponding to the liquid crystal pixel areas 131(12) and 131(22) is turned on to apply a common ground voltage Vcom2 with an alternating positive and negative pulse waveform and opposite voltage polarity to the liquid crystal pixel areas 131(12) and 131(22). The data voltages Vdata1 and Vdata2 are combined with the common ground voltage Vcom2 to form screen update voltages Vlc12 and Vlc22, respectively, which reset the screens of the liquid crystal pixel areas 131(12) and 131(22). Then, during the T3 period, the data electrode lines 141(1) and 141(2) again apply the appropriate data voltages Vdata1 and Vdata2 in an alternating positive-negative pulse waveform to the liquid crystal pixel areas 131(12) and 131(22). At the same time, the common ground electrode line 181(2) also applies the common ground voltage Vcom2, also in an alternating positive-negative pulse waveform with the opposite voltage polarity, to the liquid crystal pixel areas 131(12) and 131(22). The data voltages Vdata1 and Vdata2 are combined with the common ground voltage Vcom2 to form the screen update voltages Vlc12 and Vlc22, respectively, to accurately write the new grayscale data to the liquid crystal pixel areas 131(12) and 131(22). Finally, during the T4 period, the scan electrode line 121(2) outputs a negative cutoff voltage to close the liquid crystal pixel areas 131(12) and 131(22). The liquid crystal in the liquid crystal pixel areas 131(12) and 131(22) then waits for the liquid crystal to complete its response to the corresponding new grayscale image, and the screen update is completed.

[0040] 4, the screen refresh voltages Vlc11, Vlc21, Vlc12, and Vlc22 of any one of the liquid crystal pixel regions 131(11), 131(21), 131(12), and 131(22) are jointly formed by the data voltages Vdata1 and Vdata2 output from the data electrode lines 141(1) and 141(2) and the common ground voltages Vcom1 and Vcom2 of opposite polarity output from the common ground electrode lines 181(1) and 181(2). There is no need to use a data driver IC or a common ground driver IC to provide a high voltage; a general driver IC can provide a sufficient screen refresh voltage.

[0041] The technology and principles of the present invention can also be applied to DDS-driven active cholesteric liquid crystal display modules, so they will not be described again here. [Example]

[0042] 5, the second best embodiment of the present invention is an active-type cholesteric liquid crystal display device 1, which provides a monochrome screen display. It includes an active-type cholesteric liquid crystal display module 10, a control module 50, and a power module 60 for providing power to the control module 50. The control module 50 is further connected to the liquid crystal driving unit 160 of the active-type cholesteric liquid crystal display module 10, and controls the scan driving IC 161, the data driving IC 162, and the common ground driving IC 163. The characteristics of the active-type cholesteric liquid crystal display module 10 are the same as those described in the first best embodiment, and will not be described again here. [Example]

[0043] As shown in Figure 6A, the third best embodiment of the present invention is an active-type cholesteric liquid crystal display device 3 for multi-color or split-screen display. It includes a plurality of active-type cholesteric liquid crystal display modules 10, a control module 50, and a power module 60 for providing power to the control module 50. The control module 50 is further connected to the liquid crystal driving unit 160 of each active-type cholesteric liquid crystal display module 10, and controls the scan driving IC 161, data driving IC 162, and common ground driving IC 163. The characteristics of the active-type cholesteric liquid crystal display module 10 are the same as those described in the first best embodiment, and will not be described again here.

[0044] In this embodiment, the number of active-type cholesteric liquid crystal display modules 10 is at least two, and they can be arranged horizontally as shown in Figure 6A, or horizontally as a vertical arrangement, or even a horizontal matrix arrangement, such as 3 horizontal x 3 vertical, 4 horizontal x 4 vertical, 5 horizontal x 5 vertical, etc., to form a large screen like a TV wall. When the display screen needs to be divided and combined through the control module 50 to update the entire screen, each active-type cholesteric liquid crystal display module 10 is updated synchronously, which significantly improves the update speed of the entire large screen.

[0045] In one embodiment, the active cholesteric liquid crystal display device of this embodiment further includes a plurality of localized light-transmitting layers 909, the number of which corresponds to the number of active cholesteric liquid crystal display modules 10, and each localized light-transmitting layer 909 is located above each active cholesteric liquid crystal display module 10, as shown in Figure 1, that is, the light-incident surface of the active cholesteric liquid crystal display module 10 is used to absorb incident light of a set frequency, which is higher than the frequency of the reflected light of the active cholesteric liquid crystal display module 10. This can improve the screen contrast and display quality of the active cholesteric liquid crystal display module 10.

[0046] Specifically, if the active-type cholesteric liquid crystal display module 10 is used to display a blue screen, i.e., the cholesteric liquid crystal reflects blue light, the local transparent layer 909 is used to absorb other light spectrums (e.g., UV light) with frequencies higher than blue light. The purer the spectrum of light incident on the active-type cholesteric liquid crystal display module 10, the higher the contrast of the blue light reflected by the cholesteric liquid crystal. Similarly, if the active-type cholesteric liquid crystal display module 10 is used to display a green screen, i.e., the cholesteric liquid crystal reflects green light, the local transparent layer 909 is used to absorb other light spectrums (e.g., UV light, blue light, etc.) with frequencies higher than green light. If the active-type cholesteric liquid crystal display module 10 is used to display a red screen, i.e., the cholesteric liquid crystal reflects red light, the local transparent layer 909 is used to absorb other light spectrums (e.g., UV light, blue light, green light, etc.) with frequencies higher than red light.

[0047] In one best practice, multiple active-type cholesteric liquid crystal display modules 10 can be arranged vertically as shown in Figure 6B, including a first active-type cholesteric liquid crystal module 101, a second active-type cholesteric liquid crystal module 102, and a third active-type cholesteric liquid crystal module 103, stacked vertically from bottom to top. When the first active-type cholesteric liquid crystal module 101 displays a red screen, the second active-type cholesteric liquid crystal module 102 displays a green screen, and the third active-type cholesteric liquid crystal module 103 displays a blue screen, the active-type cholesteric liquid crystal device 3 can display a full-color screen.

[0048] In one preferred embodiment, as shown in FIG. 6B , the active-type cholesteric liquid crystal display device 3 further includes a first localized transparent layer 901, a second localized transparent layer 902, and a third localized transparent layer 903. The first localized transparent layer 901 is disposed between the first active-type cholesteric liquid crystal module 101 and the second active-type cholesteric liquid crystal module 102 and is used to absorb incident light having a frequency higher than a first set frequency. The second localized transparent layer 902 is disposed between the second active-type cholesteric liquid crystal module 102 and the third active-type cholesteric liquid crystal module 103 and is used to absorb incident light having a frequency higher than a second set frequency, which is higher than the first set frequency. The third localized transparent layer 903 is disposed above the third active-type cholesteric liquid crystal module 103 and is used to absorb incident light having a frequency higher than a third set frequency, which is higher than the second set frequency. This can improve the screen contrast and display quality of the active-type cholesteric liquid crystal display device 3.

[0049] In one specific embodiment, the first active cholesteric liquid crystal module 101 is used to reflect red light, the second active cholesteric liquid crystal module 102 is used to reflect green light, and the third active cholesteric liquid crystal module 103 is used to reflect blue light. The first set frequency is 480 trillion Hz to 530 trillion Hz, i.e., the green light spectrum band. The second set frequency is 600 trillion Hz to 620 trillion Hz, i.e., the blue light spectrum band. The third set frequency is 780 trillion Hz to 800 trillion Hz, i.e., the UV light spectrum band. When external light enters the active cholesteric liquid crystal display device 3, the UV light is first absorbed by the third local transparent layer 903, and the remaining visible light enters the third active cholesteric liquid crystal module 103. Cholesteric liquid crystal has optical rotation, and blue light with a specific optical rotation (e.g., left-handed circularly polarized light) is first reflected by the third active-type cholesteric liquid crystal module 103, while the remaining blue light with the optical rotation (e.g., right-handed circularly polarized light) passes through the third active-type cholesteric liquid crystal module 103 and is absorbed by the second localized light-transmitting layer 902, so that the visible light subsequently incident on the second active-type cholesteric liquid crystal module 102 does not contain any blue light components. Green light with a specific optical rotation (e.g., left-handed circularly polarized light) is first reflected by the second active-type cholesteric liquid crystal module 102, while the remaining green light with the optical rotation (e.g., right-handed circularly polarized light) passes through the second active-type cholesteric liquid crystal module 102 and is absorbed by the first localized light-transmitting layer 901, so that the visible light subsequently incident on the first active-type cholesteric liquid crystal module 101 does not contain any blue or green light components and is only red light. The role of passing through the first local light-transmitting layer 901, the second local light-transmitting layer 902 and the third local light-transmitting layer 903 is to effectively improve the display contrast of the first active cholesteric liquid crystal module 101, the second active cholesteric liquid crystal module 102 and the third active cholesteric liquid crystal module 103, and more significantly improve the display image quality of the entire active cholesteric liquid crystal display device 3.

[0050] The active cholesteric liquid crystal display module 10, the active cholesteric liquid crystal display device 1 and the active cholesteric liquid crystal display device 3 provided by the present invention have the following advantages:

[0051] Because a common ground driver IC is installed, when the LCD driver unit updates the screen of a liquid crystal pixel area, the scan electrode line corresponding to that liquid crystal pixel area is conductive, and the common ground electrode line and data electrode line connected to that liquid crystal pixel area are simultaneously conductive, outputting a common ground voltage Vcom and a data voltage Vdata to the liquid crystal pixel area, respectively, and the voltage polarity of the common ground voltage Vcom is opposite to that of the data voltage Vdata. As a result, the data voltage Vdata and the common ground voltage Vcom together form a cholesteric liquid crystal transition voltage. Therefore, it is sufficient to use a normal driver IC for both the common ground and the data, and there is no need for a special driver IC, which effectively reduces component costs.

[0052] The detailed description of the best embodiment above is intended to more clearly explain the features and spirit of the present invention, and is not intended to limit the scope of the present invention. Even if a person skilled in the art makes changes or adjustments within the scope of the present invention, the important meaning of the present invention will not be lost, and will still be included in the scope of the present invention. [Explanation of symbols]

[0053] 10: Active cholesteric liquid crystal display module 170: TFT element layer 171: TFT element 110:First board 150:Second board 120: Scan electrode layer 121: Scanning electrode line 140: Data electrode layer 141: Data electrode line 130: Cholesteric liquid crystal layer 131: LCD pixel area 180: Common ground electrode layer 181: Common ground electrode wire 160: LCD drive unit 161: Scan driver IC) 162: Data drive IC 163: Common ground drive IC Vscan: Scan voltage Vdata: Data voltage Vcom: Common ground voltage 1, 3: Active cholesteric liquid crystal display device 50: Control module 60: Power module 101: First active cholesteric liquid crystal module 102: Second active cholesteric liquid crystal module 103: Third active cholesteric liquid crystal module 901: First local light-transmitting layer 902:Second local transparent layer 903:Third local transparent layer 909:Local transparent layer T1: Time to reset the liquid crystal transition by applying the data voltage T2: Response time of the LCD itself T3: The time it takes for the liquid crystal to transition to the specified reflectance after applying the data voltage T4: Response time of the LCD itself

Claims

1. The display device includes a liquid crystal driving unit 160, a TFT element layer 170, a first substrate 110, a second substrate 150, and a scan electrode layer 120, a data electrode layer 140, a cholesteric liquid crystal layer 130, and a common ground electrode layer 180 disposed between the first substrate 110 and the second substrate 150. The display device has the following features: The data electrode layer 140 is adjacent to the first substrate 110 and includes M data electrode lines 141 arranged in parallel, where M is an integer greater than 1; the scan electrode layer 120 is also adjacent to the first substrate 110 and includes N scan electrode lines 121 arranged in parallel, where N is an integer greater than 1, and the horizontal projections of the scan electrode lines 121 and the data electrode lines 141 are perpendicular to each other, thereby forming M*N projection intersections; The TFT element layer 170 is also adjacent to the first substrate 110 and includes M*N TFT elements 171, each corresponding to one of the projection intersections. The source electrode of each TFT element 171 is connected to the data electrode line 141 corresponding to the vertical intersection, and the gate electrode of each TFT element 171 is connected to the scan electrode line 121 corresponding to the projection intersection. The common ground electrode layer 180 is located near the second substrate 150 and includes N common ground electrode lines 181, which are parallel to the N scan electrode lines 121; The cholesteric liquid crystal layer 130 is disposed between the common ground electrode layer 180 and the TFT element layer 170, and includes M*N liquid crystal pixel areas 131, each of which corresponds to one of the projected intersections, and one end of each of the liquid crystal pixel areas 131 is connected to one of the common ground electrode lines 181 and another end is connected to the drain electrode of one of the TFT elements 171; The liquid crystal driving unit 160 includes at least one scan driving IC 161, at least one data driving IC 162, and at least one common ground driving IC 163. The scan driving IC 161 is used to apply a scan voltage (Vscan) to each of the scan electrode lines 121. The data driving IC 162 is used to apply a data voltage (Vdata) to each of the data electrode lines 141. The common ground driving IC 163 is used to apply a common ground voltage (Vcom) to each of the common ground electrode lines 181. and when the liquid crystal driving unit 160 turns on the scan electrode line 121 corresponding to one liquid crystal pixel region 131, the common ground electrode line 181 and the data electrode line 141 connected to the liquid crystal pixel region 131 are simultaneously turned on, and the voltage polarity of the common ground voltage (Vcom) is opposite to that of the data voltage (Vdata), so that the data voltage (Vdata) and the common ground voltage (Vcom) together form a cholesteric liquid crystal transition voltage.

2. The device includes one active type cholesteric liquid crystal display module 10, one control module 50, and one power module 60 for providing power to the control module 50, and has the following features: The active type cholesteric liquid crystal display module 10 is the active type cholesteric liquid crystal display module 10 described in claim 1, and the control module 50 is further connected to the liquid crystal driving unit 160 of the active type cholesteric liquid crystal display module 10.

3. The device includes a plurality of active cholesteric liquid crystal display modules 10, one control module 50, and one power module 60 for supplying power to the control module 50, and has the following features: The active type cholesteric liquid crystal display module 10 is the active type cholesteric liquid crystal display module 10 described in claim 1, and the control module 50 is further connected to the liquid crystal driving unit 160 of each active type cholesteric liquid crystal display module 10.

4. The plurality of active-type cholesteric liquid crystal display modules 10 include a first active-type cholesteric liquid crystal module 101, a second active-type cholesteric liquid crystal module 102 and a third active-type cholesteric liquid crystal module 103, which are vertically stacked from bottom to top, 4. The active-type cholesteric liquid crystal display device according to claim 3, further comprising a first local transparent layer 901, a second local transparent layer 902 and a third local transparent layer 903, wherein the first local transparent layer 901 is disposed between the first active-type cholesteric liquid crystal module 101 and the second active-type cholesteric liquid crystal module 102 and is used to absorb incident light having a frequency higher than a first set frequency; the second local transparent layer 902 is disposed between the second active-type cholesteric liquid crystal module 102 and the third active-type cholesteric liquid crystal module 103 and is used to absorb incident light having a frequency higher than a second set frequency, the second set frequency being higher than the first set frequency; and the third local transparent layer 903 is disposed above the third active-type cholesteric liquid crystal module 103 and is used to absorb incident light having a frequency higher than a third set frequency, the third set frequency being higher than the second set frequency.

5. 4. The active-type cholesteric liquid crystal display device according to claim 3, further comprising a plurality of local light-transmitting layers 909, each of which is disposed above each active-type cholesteric liquid crystal display module 10, for absorbing incident light of a set frequency, the set frequency being different from the frequency of the reflected light of the active-type cholesteric liquid crystal display module 10.

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