Dual-light video, dual-light static-state and dual-light dual-state cholesteric display

Abstract

The present invention relates to a cholesteric liquid crystal display, and more particularly relates to a dual-light dual-state cholesteric liquid crystal display using a front-light system and a backlight system, wherein a front-light area corresponds to a reflective pixel area of a TFT storage capacitor, and a backlight area corresponds to a conventional transparent pixel area. In the present invention, a mirror-surface effect of a storage capacitor in an active matrix and a polarization-depolarization effect of cholesteric liquid crystals are used to change a storage capacitor area into an effective display area, thereby effectively expanding the total display area of a liquid crystal display. Therefore, the liquid crystal display not only can be used in indoor ambient light conditions with an excellent color gamut, but can also be used in an outdoor sunlight readable application.

Description

Bioptic video, bioptic still, and bioptic bimodal cholesteric displays Technical Field

[0001] The present invention relates to a high-aperture ratio thin-film transistor (TFT) liquid crystal display, and more specifically, to a cholesteric liquid crystal display employing a frontlight system and a backlight system, wherein the frontlight region corresponds to the reflective pixel region of the TFT storage capacitor, and the backlight region corresponds to the conventional transparent pixel region. The frontlight can be a natural ambient light beam or an artificial frontlight surface. As a result, the display can be used not only in various indoor ambient light conditions with an excellent color gamut, but also in outdoor daylight-readable applications. Background Art

[0002] A characteristic of cholesteric liquid crystal displays is that the image remains on the display even when the driving voltage is disconnected. Bistability and multistability ensure completely flicker-free static displays and have the potential for unlimited multiplexing to produce giant displays and / or ultra-high-resolution displays. In cholesteric liquid crystals, the molecules are oriented in a spiral that has a periodic characteristic of the material. In the planar state, the axis of the spiral is perpendicular to the plane of the display. Light with a wavelength that matches the pitch of the spiral is reflected, and the display appears bright. If an alternating current (AC) voltage is applied, the structure of the liquid crystal changes from a planar texture to a focal conic texture. The main characteristic of the focal conic state is its highly diffuse light scattering appearance caused by the distribution of small birefringent domains, with a sudden change in refractive index at the boundaries between these domains. The texture has no single optical axis and the focal conic texture is usually milky white (i.e., white light scattering). The planar texture and the focal conic texture can coexist in the same panel or entity, which is a very important property for display applications, thereby achieving grayscale.

[0003] Current cholesteric displays utilize "Bragg reflection," one of the inherent properties of the cholesteric phase. In Bragg reflection, only a portion of the incident light with the same handedness of circular polarization and within a specific wavelength band can be reflected to the viewer, resulting in a monochrome display. However, the remaining spectrum of the incident light (including 50% of the wavelength band with opposite circular polarization chirality and outward Bragg reflection) will pass through the display and be absorbed by the black coating material on the back substrate of the display to ensure contrast. The overall light utilization efficiency is quite low. Bragg-type reflection gives the impression that monochrome display is one of the unique characteristics of cholesteric liquid crystal displays (CLCDs).

[0004] U.S. Patent No. 5,796,454 describes a black-and-white backlit cholesteric liquid crystal (CLC) display. The black-and-white backlit CLC display comprises a controllable CLC structure, a first circular polarizer laminated to a first substrate having cells with the same circular polarity as the liquid crystal, a second circular polarizer laminated to a second substrate having cells with opposite circular polarity as the liquid crystal, and a light source. The black-and-white backlit display is preferably illuminated by a light source that produces natural "white" light. Therefore, when the display is illuminated by incident light, the circular polarizer transmits 50% of the incident light with right-handed circular polarization. When the CLC is in the on state, the light reflected by the CLC is the portion of the incident light with a wavelength within its inherent spectral bandwidth and the same chirality, while the portion of light transmitted through the CLC is the complementary color of the CLC's inherent color. The transmitted light has right-handed circular polarization, which is therefore blocked by the left-handed circular polarizer, resulting in the viewer perceiving that area of ​​the display as essentially black. When the display is off, light transmitted through the polarizer is scattered by the CLC. The forward-scattered portion of the incident light is emitted from the controllable CLC structure as depolarized light. The left-handed circularly polarized portion of the forward-scattered light is transmitted through the left-handed circular polarizer and perceived by the viewer. In U.S. Patent No. 5,796,454, the black and white display is generated by the backlight assembly, and the ambient light is merely noise.

[0005] U.S. Patent No. 6,344,887, incorporated herein by reference, describes a method for manufacturing a full-spectrum reflective cholesteric display. This patent discloses a cholesteric display that uses a polarizer with the same polarity as the liquid crystal. The display utilizes two types of reflection: Bragg reflection (primary reflection) and metallic reflection (secondary reflection). The display utilizes a circular polarizer and a metallic reflective film on the back of the display to direct the second component of incident light back toward the viewer.

[0006] U.S. Patent No. 6,873,393, which is incorporated herein by reference, describes a method for producing a black-and-white or color cholesteric display without using Bragg reflection. This patent discloses a cholesteric display that uses a front polarizer with a polarity opposite to that of the liquid crystal. The display unit structure functions solely as a light shutter that turns incident light on and off. In a black-and-white display mode, the white state is achieved by metallic reflection from the cholesteric planar textured regions, while the black state is achieved by the cholesteric depolarization effect of the cholesteric focal conic textured regions and the filtering effect of the polarizer. In a full-color mode, the full-color state is produced by the metallic reflectors and micro-color filters of the cholesteric planar textured regions, while the black state is achieved by the cholesteric focal conic textured regions.

[0007] U.S. Patent No. 7,564,518 describes a reflective cholesteric display using two circular polarizers. The front circular polarizer has a predetermined polarity opposite to that of both the display's Bragg reflector and the back reflective circular polarizer. The display system employs an absorptive weak polarizer with high transmittance. In black-and-white display mode, the white state is achieved by cholesteric focal conic textured regions, while the black state is achieved by cholesteric planar textured regions. In full-color mode, the full-color state is achieved by micro-color filters in the cholesteric focal conic textured regions, while the black state is achieved by the cholesteric planar textured regions.

[0008] Patent US20200233254A1 introduces a cholesteric display using a substrate with a mirror, in which the monochrome liquid crystal structure includes a field-induced nematic vertical orientation texture and a cholesteric focal conic texture, which is incorporated herein by reference. A front circular polarizer is attached to the front substrate. The mirror covers all ITO common areas and the drain area of ​​the TFT to make the display a purely reflective cholesteric display device, which is an ideal solution for black and white displays. However, when it is used for full-color display applications (in which a color filter (CF) is provided in front of the substrate and the front light passes through the CF film twice via a reflective metal layer), the color quality (e.g., color saturation and color brightness) is not as good as that of a single-light-path backlight display. Summary of the Invention

[0009] The main purpose of the present invention is to realize a front-light and back-light dual-light TFT cholesteric liquid crystal display.

[0010] Another object of the present invention is to create a color filter pattern that covers the storage capacitor area of ​​the TFT array or active matrix that is the reflective display area.

[0011] Yet another object of the present invention is to create a color filter pattern to cover most of the pixel area that is a transmissive display area.

[0012] Another object of the present invention is to increase the total aperture ratio of a TFT display.

[0013] Yet another object of the present invention is to create red, green, blue and white color filter patterned pixel structures.

[0014] It is a further object of the present invention to create a display structure in which the reflective display and the transmissive display share the same optically on state and optically off state.

[0015] It is yet another object of the present invention to create a field-induced nematic vertical alignment texture as a reflective video optical off-state.

[0016] Yet another object of the present invention is to create a field-induced nematic eddy alignment texture as a reflective video optical turn-on state.

[0017] It is a further object of the present invention to create a reflective static off state in a cholesteric plane texture.

[0018] Yet another object of the present invention is to obtain a reflective static on-state in a cholesteric focal conic texture.

[0019] It is a further object of the present invention to achieve a full-color display that is sunlight readable.

[0020] An embodiment of the first aspect of the present invention provides a dual-light video cholesteric display, comprising a transparent conductive front substrate having a color filter layer, a first circular polarizer layer, a cholesteric liquid crystal layer, an active matrix back substrate, a second circular polarizer layer, a backlight surface, and a frontlight surface. The cholesteric liquid crystal layer has at least one field-induced vertical alignment region and at least one field-induced vortex alignment region, and the active matrix back substrate has a first displayable window region and a second displayable window region. The transparent conductive front substrate, together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate, together with the second circular polarizer layer, are juxtaposed to form a display structure. A backlight beam from the backlight surface that passes through the first displayable window region and the field-induced vortex alignment region is modulated into depolarized light to form an optically on state having at least one grayscale level; and backlight that passes through the first displayable window region and the field-induced vertical alignment region is absorbed by the first circular polarizer layer and the second circular polarizer layer to form an optically off state. The frontlight beam reflected from the frontlight surface by the field-induced vortex alignment region from the second displayable window area of ​​the active matrix substrate is modulated into depolarized light to form an optically on state having at least one grayscale level; the frontlight reflected from the second displayable window area by the field-induced vertical alignment region is absorbed by the first circular polarizer layer to form an optically off state. The field-induced vertical alignment region and the field-induced vortex alignment region are instantaneously interchangeable at video frequencies, thereby allowing viewers to observe high-brightness video-rate full-color motion images in both indoor and outdoor environments.

[0021] In some embodiments, the first circular polarizer layer and the second circular polarizer layer have opposite polarities.

[0022] In some embodiments, the first displayable window area is a conventional transmissive area of ​​an active matrix.

[0023] In some embodiments, the second displayable window area is a reflective metal electrode area of ​​a storage capacitor of an active matrix.

[0024] In some embodiments, the high brightness display under indoor and outdoor environmental conditions means that in a dark environment, the backlight is the main light source, while in outdoor conditions, the frontlight is the main light source.

[0025] In some embodiments, the display is a transmissive display for dark environments.

[0026] In some embodiments, the display is a transflective display for an outdoor environment.

[0027] In some embodiments, the display is a reflective display under daylight conditions.

[0028] In some embodiments, the video speed of the display is in the range of 30 FPS to 140 FPS.

[0029] An embodiment of the second aspect of the present invention provides a dual-light static cholesteric display, comprising a transparent conductive front substrate having a color filter layer, a first circular polarizer layer, a cholesteric liquid crystal layer, an active matrix back substrate, a second circular polarizer layer, a backlight surface, and a frontlight surface. The cholesteric liquid crystal layer has at least one cholesteric planar texture region and at least one cholesteric focal conic texture region, and the active matrix back substrate has a first displayable window region and a second displayable window region. The transparent conductive front substrate, together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate, together with the second circular polarizer layer, are juxtaposed to form a display structure. A backlight beam from the backlight surface that passes through the first displayable window region and the cholesteric focal conic texture region is modulated into depolarized light to form an optically on state having at least one grayscale level; and backlight that passes through the first displayable window region and the cholesteric planar texture region is absorbed by the first circular polarizer layer and the second circular polarizer layer to form an optically off state. In which, the front light beam from the front light surface reflected from the second displayable window area of ​​the active matrix substrate through the cholesteric phase focal conic texture area is modulated into depolarized light to form an optically open state with at least one grayscale level; the front light reflected from the second displayable window area through the cholesteric phase plane texture area is absorbed by the first circular polarizer layer to form an optically closed state, so that the viewer will observe a high-brightness, power-free and flicker-free picture under indoor and outdoor environmental conditions.

[0030] In some embodiments, the optically off state in the second displayable window area is caused by a 180° phase shift of a reflective metal electrode area of ​​a storage capacitor of the active matrix.

[0031] In some embodiments, the optically off state in the first displayable window region is caused by a circular polarization guiding effect of the cholesteric plane textured region.

[0032] In some embodiments, the optically on state in the first displayable window region and the second displayable window region is caused by a depolarization effect of the cholesteric focal conic textured region.

[0033] In some embodiments, the sum of the areas of the first displayable area and the second displayable area is a numerator of a modified aperture ratio of the bi-optic static cholesteric display.

[0034] In some embodiments, the modified aperture ratio of the bi-optic static cholesteric display is greater than or equal to 55%. The modified aperture ratio of the bi-optic static cholesteric display of the present invention is at least 15% greater than the conventional aperture ratio.

[0035] An embodiment of the third aspect of the present invention provides a dual-light dual-state cholesteric display, comprising a transparent conductive front substrate having a color filter layer, a first circular polarizer layer, a cholesteric liquid crystal layer, an active matrix back substrate, a second circular polarizer layer, a backlight surface, and a frontlight surface. The cholesteric liquid crystal layer comprises at least one unstable field-induced vertical alignment region and at least one unstable field-induced vortex alignment region, as well as at least one bistable cholesteric planar texture region and at least one bistable cholesteric focal conic texture region. The conductive front color filter substrate, together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate, together with the second circular polarizer layer, are juxtaposed to form a display structure. A light beam from the backlight surface that passes through the field-induced vortex alignment region and / or the cholesteric focal conic texture region is modulated into depolarized light to form an optically on state; light that passes through the field-induced vertical alignment region and / or the cholesteric planar texture region is absorbed by the first and second circular polarizer layers to form an optically off state. In which, the light beam from the front light surface reflected from the metal electrode through the field-induced eddy current orientation region and / or through the cholesteric phase focal conic texture region is modulated into polarized light to form an optically open state; and the light reflected from the metal electrode through the field-induced vertical orientation region and / or the cholesteric phase plane texture region is absorbed by the first circular polarizer layer to form an optically closed state, whereby the viewer will observe the video display and the static display in indoor and outdoor environments, respectively.

[0036] In some embodiments, the video display state and the static display state are controllable cholesteric display states.

[0037] In some embodiments, the video display is a dynamic browsing mode display.

[0038] In some embodiments, the static display is a static no-power no-flicker reading learning mode display.

[0039] In some embodiments, the optical switching on and off effects are caused by polarization and depolarization effects of cholesteric phase molecules.

[0040] The present invention utilizes the mirror effect of the storage capacitor in the active matrix and the polarization-depolarization effect of the cholesteric liquid crystal to transform the storage capacitor area into an effective display area, effectively expanding the total display area of ​​the liquid crystal display. Therefore, the high-aperture ratio TFT liquid crystal display of the present invention can be used not only in indoor ambient light conditions with excellent color gamut, but also in outdoor applications where it is readable in daylight. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 a shows a schematic structure of a prior art TFT cholesteric display.

[0042] FIG. 1 b shows a schematic opening structure of a prior art TFT cholesteric display.

[0043] 2a and 2b show schematic opening structures of reflective and transmissive full-color TFT cholesteric displays.

[0044] FIG3 shows the optical behavior of a front-lit and back-lit display in bistable cholesteric display mode.

[0045] FIG4 shows the optical behavior of the frontlight and backlight displays in astable homeotropic nematic mode.

[0046] FIG5 illustrates the optical behavior of a bi-optical bi-state display.

[0047] FIG6 shows a sub-pixel image of a dual-light TFT design.

[0048] FIG. 7 illustrates switching between a video astable display mode and a no-power bi-stable display mode.

[0049] FIG8 shows the first still color frame of a motion video stream.

[0050] FIG9 shows a second still color picture of the same motion video stream. DETAILED DESCRIPTION

[0051] Referring first to Figure 1a, a schematic diagram of a prior art TFT pattern for a cholesteric display is shown. A metal gate electrode 101 is one of the horizontal scan lines of the TFT array structure, deposited directly on the TFT substrate via a first photolithographic patterning process. A metal source electrode 102 is one of the vertical data lines of the TFT array structure. A transparent conductive ITO electrode 103 occupies the majority of the pixel area. Thin-film transistor islands 104, comprising gate, source, and drain triodes, are located at the corners of the TFT pixel area, with the gate contacting the scan line 101, the source contacting the data line 102, and the drain contacting the transparent conductive electrode 103. The metal electrode is isolated from the overlapping portion of the transparent electrode 103 by a thin layer of silicon nitride to form a storage capacitor region 105. Whether it is the gate (on-gate capacitor, COG) or the common electrode (common capacitor, COC), the storage capacitor is essential for working with the cholesteric liquid crystal to adequately retain charge during frame addressing. However, the presence of the storage capacitor has a negative impact on the aperture ratio of the backlight display.

[0052] Now turn to Figure 1b, which shows the opening area of ​​the TFT pixel shown in Figure 1a. The dotted area 108 represents the pixel area (PA) of the TFT. For a black and white display, the dotted area 108 can be a square, and for a full-color display, the dotted area 108 can be a rectangle. Area 106 is the opening of the TFT pixel, that is, the CF window structure that allows backlight to pass through. The remaining area 107 covered by the black matrix (BM1) on the common substrate is not transparent to artificial backlight and natural ambient light. The ratio of the area of ​​area 106 to the area of ​​area 108 is generally referred to as the aperture ratio (AR) of the display, which can be defined as Formula 1:

[0053] The AR is in the range of 0.3 to 0.6, depending on the display resolution. In the example shown in Figures 1a and 1b, the AR is 0.45, which is a typical figure for high-resolution TFT displays.

[0054] Turning now to Figures 2a and 2b, which show the schematic structure of a reflective and transmissive full-color TFT cholesteric display. The dotted area 208 represents the black matrix area BM2 of the newly designed TFT pixel, which fully covers the TFT thin film transistor island, gate and source to prevent light leakage from the TFT pixel. Obviously, the BM2 area 208 is a non-display area. The first displayable area (FDA) 206 is a window structure covered by a portion of a predetermined color filter, which allows the backlight 220 to pass through to form a light beam 221. The second displayable area (SDA) 207 is a window structure covered by another portion of a predetermined color filter on the opaque storage capacitor 215 area, which allows the frontlight 230 to be reflected to the viewer as a light beam 231. Therefore, FDA 206 is the backlight area, and SDA 207 is the frontlight area. Obviously, FDA 206 is equivalent to the CF area 106 shown in Figure 1b. The relationship between BM1 and BM2 can be defined as Formula 2: BM2 = BM1 - SDA (2)

[0055] The working principle of the bi-optical display will be described later.

[0056] Compared to the AR of the prior art cholesteric TFT display described in FIG1 b, the relationship between the total display areas 206 and 207 and the BM2 non-display area 208 can be referred to as the modified aperture ratio (MAR) of the state-of-the-art display of the present invention, which can be described mathematically as Equation 3: PA = FDA + SDA + BM2 (3)

[0057] The relationship between MAR and AR can be described as Equation 4:

[0058] It's well understood in the art that AR is limited by TFT design, particularly by the display's resolution. The higher the display's resolution, the lower the AR. The opaque storage capacitor area is one of the primary factors affecting the display's aperture ratio. However, the latest technology in this invention utilizes the mirror effect of the storage capacitor's aluminum electrode and the polarization-depolarization effect of cholesteric liquid crystals to transform the storage capacitor area into a second, active displayable area (SDA), thereby expanding the total display area by 15-20%.

[0059] Different from conventional transflective displays (which sacrifice aperture ratio by using specific internal structures or sacrifice display brightness by some transflective coatings on the outside of the TFT panel), the applicant prefers to name this new type of display as front-light and back-light dual-mode cholesteric display (DBCD).

[0060] As an embodiment of the present invention, Figure 3 shows a cross-sectional structure of a dual-light static cholesteric display, i.e., a front-light and back-light display in static display mode. The dual-light static cholesteric display 301 includes a transparent conductive front substrate 310, a cholesteric liquid crystal layer 340, an active matrix 322, and a back substrate 320. The transparent conductive front substrate 310 has a color filter layer 311 on one side and a first circular polarizer layer 330 on the other side. A common electrode layer 312 is sputtered on top of the color filter layer 311. The active matrix 322 is fabricated on the inner side of the back substrate 320, forming the active matrix back substrate 302. A second circular polarizer layer 331 is attached to the outer side of the back substrate 320. A storage capacitor 321 is also provided on the active matrix 322. It should be noted that the transparent conductive front substrate 310 has a color filter layer. The transparent conductive front substrate 310 itself may have a color filter layer, that is, the transparent conductive front substrate 310 and the color filter layer are a whole. Alternatively, the transparent conductive front substrate 310 and the color filter layer may be two relatively independent layers. The combination of the two is included in the protection scope of the present invention.

[0061] The cholesteric liquid crystal layer 340 includes at least one cholesteric planar texture region 341 and at least one cholesteric focal conic texture region 342. The active matrix back substrate 302 includes a first displayable window region 303 and a second displayable window region 304. The reflective metal electrode region of the storage capacitor 321 forms the second displayable window region 304.

[0062] When a cholesteric-nematic phase transition voltage is applied to the cholesteric liquid crystal layer 340 and then rapidly reduced to zero voltage, the liquid crystal molecules gradually form a stable cholesteric planar texture 341, thereby maintaining the display in an optically off state. Backlight beam 350 from the backlight panel passes through the backlight surface and reaches the right-handed (RH) second circular polarizer layer 331, where it is converted into RH circularly polarized light. This light component continues to pass through the cholesteric planar texture 341 of the liquid crystal layer without attenuation or phase change. Ultimately, this light component is substantially absorbed by the front left-handed (LH) first circular polarizer layer 330. Therefore, the viewer will not see the light. At the same time, the frontlight beam 360 (whether artificial frontlight or ambient light) reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light. This light component passes through the cholesteric phase plane texture 341 without attenuation and phase change until it is reflected by the aluminum reflective layer of the storage capacitor 321. Through this reflection, the light beam is converted into RH circularly polarized light with a 180° phase shift. This light component is substantially absorbed by the front LH first circular polarizer layer 330.

[0063] Similarly, when the liquid crystal molecules in the liquid crystal layer 340 are driven by appropriate voltage pulses to a stable cholesteric focal conic texture 342 (cholesteric focal conic texture) or a multistable state (cholesteric planar and focal conic coexisting texture), the display operates in an optically on state with different grayscale levels. Light scattering and depolarization are typical phenomena of cholesteric focal conic texture. As mentioned above, planar texture and focal conic texture can coexist in the same panel or entity, which is a very important feature for display applications, thereby achieving grayscale.

[0064] Light beam 350 from the backlight panel passes through the backlight surface and reaches the RH second circular polarizer layer 331. Over 40% of light beam 350 is converted into RH circularly polarized light 351, which, with some degree of diffusion and depolarization, forms light component 352 that passes through the cholesteric focal conic texture region 342 of the liquid crystal layer. Ultimately, this light component substantially passes through the front LH circular polarizer 330 to form light component 353 with controllable intensity and color. Simultaneously, frontlight light beam 360 (whether artificial frontlight or ambient light) passes through the frontlight surface and reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light 361. This light component is depolarized by the focal conic texture and further reflected by the reflective metal electrode region, i.e., the aluminum electrode, of the storage capacitor 321, forming RH circularly polarized light 362 through this reflection, ultimately appearing as light component 363. As a result, the viewer sees a color image.

[0065] As another embodiment of the present invention, FIG4 illustrates a cross-sectional structure of a bi-optic video cholesteric display, i.e., a frontlight and backlight display in a dynamic video display mode. The composition of the cholesteric liquid crystal layer 440 of the bi-optic video cholesteric display shown in FIG4 differs from the cholesteric liquid crystal layer 340 of the bi-optic static cholesteric display shown in FIG3 of the previous embodiment. However, FIG4 and FIG3 generally share the same arrangement of the transparent conductive front substrate, color filter layer, first circular polarizer layer, second circular polarizer layer, and active matrix back substrate.

[0066] In FIG4 , the cholesteric liquid crystal layer 440 has at least one field-induced vertical alignment region 441 and at least one field-induced eddy current alignment region 442. Deposited on the transparent conductive front substrate 310 is an absorption color filter layer 311 comprising red, green, blue, and black light-shielding layer (BM) patterns, or in other cases, comprising red, green, blue, white, and BM patterns. A common ITO (Indium Tin Oxides) electrode 312 is sputtered on top of the color filter layer 311 as a common electrode layer. The thickness of the color filter layer 311 is typically in the range of 0.4-1.2 microns, preferably 0.8-1.0 microns. A polyimide alignment layer is deposited on top of the common electrode layer. Furthermore, a first circular polarizer layer 330 is located on the outside of the transparent conductive front substrate 310. A TFT active matrix 322 is fabricated on the inside of the back substrate 320, forming the active matrix back substrate 302. Storage capacitors 321 are arranged on the TFT active matrix 322, occupying approximately 20% of the pixel area of ​​the TFT active matrix back substrate 302. A second circular polarizer layer 331 is attached to the outside of the back substrate 320. The optical helices of the first and second circular polarizer layers 330 and 331 are designed to oppose each other.

[0067] Within the TFT active matrix back substrate 302, gate lines for transmitting external scan signals, gate electrodes serving as branches of the gate lines, and storage capacitor electrodes parallel to the gate lines are formed on a transparent insulating substrate 320, such as glass. A gate insulating layer is formed on the transparent insulating substrate. Data lines, perpendicular to the gate lines and transmitting external display signals, are formed on portions of the gate insulating layer. A semiconductor and N+ layer are formed on the gate insulating layer and gate electrode. Source and drain electrodes are formed on a layer with ohmic contacts, and the source electrode is connected to the data line. In this embodiment, the gate electrode, source, drain, gate insulating layer, semiconductor, and N+ layer form the TFT active matrix 322. The TFT channel is formed in the portion of the amorphous silicon (a-Si) layer between the source and drain electrodes. When a scan signal is applied to the gate electrode via the gate line, the TFT turns on; the display drive voltage is applied to the source electrode via the data line, and then to the drain electrode via the channel in the a-Si layer. Charge is efficiently stored in the storage capacitor 321 within the frame with a 99% retention rate. Voltage is dropped from the transparent insulating substrate (ie, back substrate 320) of the TFT active matrix back substrate 302 to the transparent conductive front substrate 310 to address the cholesteric liquid crystal layer 440 to different controllable optical states. The transparent conductive front substrate 310 is a common substrate.

[0068] The cholesteric liquid crystal layer 440 has at least one field-induced vertical alignment region and at least one field-induced vortex alignment region. When the cholesteric liquid crystal layer 440 is addressed with a field-induced vertical alignment (FVA) texture 441 by a driving voltage level, the display operates in an optically closed state. The backlight beam 450 from the backlight panel passes through the backlight surface and reaches the right-handed (RH) second circular polarizer layer 331, and is converted into RH circularly polarized light, which will continue to pass through the liquid crystal FVA texture 441, i.e., the field-induced vertical alignment region, without attenuation and phase change. Finally, the light component will be substantially absorbed by the front left-handed (LH) first circular polarizer layer 330. Therefore, the viewer will not see the light. At the same time, the frontlight beam 460 (whether artificial frontlight or ambient light) reaches the LH first circular polarizer layer 330 and is converted into LH circular polarization light. It will pass through the liquid crystal FVA texture without attenuation and phase change until it is reflected by the aluminum reflector of the storage capacitor 321. Upon reflection, the beam is converted into RH circular polarization light through a 180° phase shift. This light component will be substantially absorbed by the front LH first circular polarizer layer 330.

[0069] Similarly, when the cholesteric liquid crystal layer 440 is addressed with a field-induced eddy alignment (FEA) texture 442, the display operates in optically on states with varying grayscale levels. At the same drive voltage level, the field-induced nematic liquid crystal has the same tilt angle θ relative to the normal, but with different domain orientations. Within the FEA, there are many domains, each with the same tilt angle θ relative to the display normal, but with azimuth angles that can vary from 0° to 180°. The tilt angle θ is inversely proportional to the drive voltage, varying from 0° to 90°. Liquid crystal eddies can form between domains, with their size and shape depending on the drive voltage, the surface alignment material, and the elastic properties of the liquid crystal. Light scattering and depolarization are typical phenomena of the eddy current effect. It is important to note that both FVA and FEA textures are electrically driven or field-induced nematic states, which can be simultaneously and instantaneously interchanged without any delay or relaxation, as shown in FIG4 . This is the principle of the video-speed astable display of the present invention.

[0070] Light beam 450 from the backlight panel passes through the backlight surface and reaches the RH second circular polarizer layer 331. Over 40% of light beam 450 is converted into RH circularly polarized light 451. Light component 452, formed with some diffusion and depolarization, passes through the liquid crystal FEA texture, i.e., the field-induced vortex alignment region 442. Ultimately, this component passes substantially through the front LH circular polarizer 330 to form light component 453 with controllable intensity and color. Generally, a larger tilt angle and a lower applied voltage result in a higher brightness of the resulting output light. Simultaneously, frontlight light beam 460 (whether artificial frontlight or ambient light) passes through the frontlight surface and reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light 461. This light beam is depolarized by the liquid crystal FVA texture, i.e., the field-induced vertical alignment texture 441, and further reflected by the reflective metal electrode region, i.e., the aluminum electrode, of the storage capacitor 321. This reflection converts the light beam into RH circularly polarized light 462, ultimately emerging as light component 463. As a result, the viewer will see a color image.

[0071] Turning now to FIG. 5 , a four-pixel picture of a bi-optical bi-state TFT display is shown, wherein the first pixel contains a static cholesteric liquid crystal planar texture 541 , the second pixel contains a static cholesteric liquid crystal focal conic texture 542 , the third pixel contains a dynamic field-induced homeotropic texture 543 , and the fourth pixel contains a dynamic field-induced vortex-oriented texture 544 .

[0072] As shown in Figure 5 , the cholesteric liquid crystal planar texture 541 contained in the first pixel and the cholesteric liquid crystal focal conic texture 542 contained in the second pixel constitute the optically dark and optically bright states of the static and steady-state display. When a cholesteric-to-nematic phase transition voltage is applied to the cholesteric liquid crystal layer 540 and then rapidly reduced to zero voltage, the liquid crystal molecules gradually form a stable cholesteric planar texture 541, thereby maintaining the display in the optically off state. A backlight beam 550 from the backlight panel passes through the backlight surface and reaches the right-handed (RH) second circular polarizer layer 331, where it is converted into RH circularly polarized light 551. This light component continues to pass through the cholesteric planar texture 541 of the liquid crystal layer without attenuation or phase change. Ultimately, the light component is substantially absorbed by the front left-handed (LH) first circular polarizer layer 330. Therefore, the viewer will not see the light. At the same time, the front light beam 560 (whether artificial front light or ambient light) reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light 561, which will pass through the cholesteric plane texture without attenuation and phase change until it is reflected by the aluminum reflective layer of the storage capacitor 321. Through this reflection, the beam is converted into RH circularly polarized light 562 with a 180° phase shift. This light component will be substantially absorbed by the front LH first circular polarizer layer 330.

[0073] Similarly, when the liquid crystal molecules in the liquid crystal layer 540 are driven by appropriate voltage pulses to a stable cholesteric focal conic texture 542 (cholesteric focal conic texture) or to a multistable state (cholesteric planar and focal conic coexisting texture), the display operates in an optically on state with different grayscale levels. Light scattering and depolarization are typical phenomena of cholesteric focal conic texture. As mentioned above, planar texture and focal conic texture can coexist in the same panel or entity, which is a very important feature for display applications, thereby achieving grayscale.

[0074] Light beam 550 from the backlight panel passes through the backlight surface and reaches the RH second circular polarizer layer 331. Over 40% of light beam 550 is converted into RH circularly polarized light, which is then depolarized with some diffusion to form light component 552 that passes through the cholesteric focal conic texture region of the liquid crystal layer. Ultimately, this component will substantially pass through the front LH circular polarizer 330 to form light component 556 with controllable intensity and color. Simultaneously, frontlight light beam 560 (whether artificial frontlight or ambient light) passes through the frontlight surface and reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light. This light component is depolarized by the focal conic texture and further reflected by the reflective metal electrode region, i.e., the aluminum electrode, of the storage capacitor 321, ultimately appearing as light component 563. As a result, the viewer sees a color image.

[0075] As shown in Figure 5, the dynamic field-induced vertical alignment texture 543 contained in the third pixel and the dynamic field-induced vortex alignment texture 544 contained in the fourth pixel constitute the optical dark state and optical bright state of the dynamic display. When the cholesteric liquid crystal layer 540 is addressed with the field-induced vertical alignment (FVA) texture 543 by the driving voltage level, the display operates in the optically closed state. The backlight beam 550 from the backlight panel passes through the backlight surface and reaches the right-handed (RH) second circular polarizer layer 331, and is converted into RH circularly polarized light 553, which will continue to pass through the liquid crystal FVA texture 543, i.e., the field-induced vertical alignment area, without attenuation and phase change. Finally, the light component will be basically absorbed by the front left-handed (LH) first circular polarizer layer 330. Therefore, the viewer will not see the light. At the same time, the frontlight beam 560 (whether artificial frontlight or ambient light) reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light 564, which will pass through the liquid crystal FVA texture without attenuation and phase change until it is reflected by the aluminum reflector of the storage capacitor 321, through which it is transformed into RH circularly polarized light 565 through a 180° phase shift. This light component will be substantially absorbed by the front LH first circular polarizer layer 330.

[0076] Similarly, when the liquid crystal layer 540 is addressed with a field-induced eddy alignment (FEA) texture 544, the display operates in an optically on state with different grayscale levels. At the same drive voltage level, the field-induced nematic liquid crystal has the same tilt angle θ relative to the normal direction, but has different domain orientations. In the FEA, there are many domains, where the tilt angle θ relative to the normal direction of the display is the same, but the azimuth angle can vary from 0° to 180°. The tilt angle θ is inversely proportional to the drive voltage and varies from 0° to 90°. Liquid crystal eddies can form between domains, and the size and shape of the eddies depend on the drive voltage, the surface alignment material, and the elastic properties of the liquid crystal. Light scattering and depolarization are typical phenomena of the eddy current effect. It should be noted that both FVA textures and FEA textures belong to electrically driven or field-induced nematic states, which can be simultaneously and instantaneously interchanged without any delay or relaxation process.

[0077] The light beam 550 from the backlight panel passes through the backlight surface and reaches the RH second circular polarizer layer 331, and more than 40% of the light beam 550 will be converted into RH circularly polarized light, which passes through the liquid crystal FEA texture, i.e., the field-induced eddy current alignment region, with a certain degree of diffusion and depolarized light 554. Finally, this component will substantially pass through the front LH first circular polarizer layer 330 to form a light component 557 with controllable intensity and color. Generally, the larger the tilt angle and the lower the voltage applied to it, the higher the brightness of the emitted light will be. At the same time, the front light beam 560 (whether it is artificial front light or ambient light) passes through the front light surface and reaches the LH first circular polarizer layer 330 and is converted into LH circularly polarized light, which will be depolarized by the FEA texture and reflected by the metal electrode region of the storage capacitor 321 to become the reflected light 566, and finally form the emitted light component 567 through the first circular polarizer layer 330. As a result, the viewer will see a color image.

[0078] As another important embodiment of the present invention is a dual-light and dual-state cholesteric display, the combination of a bistable cholesteric display and an unstable cholesteric display has been described in FIG. 5 and can be seamlessly combined to achieve a dual-light and dual-state TFT display. The term "dual-state" means that the display can operate in a powerless static mode and a video-rate dynamic mode. In U.S. Patent Application 17 / 842318, the applicant has comprehensively introduced the optoelectronic working principle, electronic driving method or voltage waveform of the new display, which is described in detail as follows:

[0079] 1. Driving of the cholesteric planar state

[0080] When the display is just manufactured from the LCD production line, the initial state will be the cholesteric planar texture or the optically dark state. When the driving voltage level rises from zero to the level V1 (V < V1), the display remains in the steady-state planar state.

[0081] 2. Cholesteric planar to focal cone transition

[0082] In the rising part of the curve where the voltage level is between V1 and V2 (V1 < V ≤ V2), a cholesteric phase transition from the planar state to the focal cone state occurs. Within this part, the helical pitch of the cholesteric phase structure remains the same, but its helical axis becomes more random with the increase of the voltage. At this time, it is a state where the planar and the focal cone coexist. The transmittance of the curve allows for arranging many gray levels for the static display, which can be called the multistability of the cholesteric display. The rising part of the curve (referred to as γ1 in this article) has a positive slope.

[0083] 3. Driving of the saturated cholesteric focal cone state

[0084] In the voltage range V2 < V < V3, the display presents a saturated cholesteric focal cone state and has the brightest brightness. The voltage V3 can also be expressed as Vth , which is the threshold voltage from the cholesteric phase state to the field-induced nematic state.

[0085] 4. Driving of the field-induced vortex state

[0086] When the increasing voltage crosses V th , the EO curve gradually decreases from the optically-on (ON) state to the optically-off (OFF) state. This is a dynamically turbulent state excited by the voltage V, where V3 < V ≤ V4, and the brightness of the display decreases as the voltage increases. The tilt angle θ of the liquid crystal molecules varies from 0 to π as a function of the driving voltage. In the present invention, the transmission of the descending curve can be allowed to arrange many gray levels of the non-steady-state display, and this part of the descending curve can be defined as γ2 with a negative slope.

[0087] 5. Driving of the field-induced vertical alignment state

[0088] When the voltage exceeds V4 (V ≥ V4), the field-induced vertical alignment state can also be simplified to the "H" state in the field. In the "H" state, the liquid crystal molecules are vertically aligned (VA) with the substrate of the display, making the display present a minimum transmittance or an optically-off (OFF) state.

[0089] 6. Phase separation line

[0090] On the right side of the phase separation line is the field-induced nematic phase, where a non-steady-state display mode with video rate and multiple gray levels can be achieved. On its left side is the cholesteric phase, where a bistable or multistable gray level display mode can be obtained. Through the fast path crossing the phase separation line, the non-steady-state mode and the bistable mode can be interchanged. The fast path represents the relaxation mechanism from the vertical alignment texture to the planar texture, and the molecular relaxation of the liquid crystal is the bridge connecting these two display modes. The relaxation process can be divided into four stages: First, the delay time when the vertical alignment structure still exists in the cell; second, the fast relaxation period when the transient planar structure is formed; third, when the equilibrium pitch is reached; and finally, the slow relaxation period when the final planar structure is formed. Initially, by changing the polar angle of the director orientation (the angle between the director and the normal of the cell surface) from 0 to π / 2 (about 1.25 milliseconds), the liquid crystal changes from the vertical alignment through the intermediate conical structure to the quasi-equilibrium transient planar state. The fact that the relaxation of the equilibrium wavelength is completed within about 10 milliseconds means that the equilibrium cholesteric pitch is reached, and the next relaxation process is only a macroscopic structure change. After removing the electric field, the relaxation time interval is 0.5 milliseconds to 10 milliseconds.

[0091] Based on the above EO curve, the driving device of the non-steady-state video display can be described as follows:

[0092] 1. Startup

[0093] Whether it is a brand-new display provided by a display manufacturer or a display in a power-off static state, a voltage pulse with a sufficient pulse width and higher than V4 is applied to all pixels of the display panel to set the display to the black field-induced vertical alignment state. The startup time does not affect the video frame rate because it is part of the pipelined waveform.

[0094] 2. Frame Addressing

[0095] All levels of the analog signal with voltage levels within the range of curve γ2 (V3 < V ≤ V4) are sorted line-by-line by the TFT gate signal and latched to each individual TFT source of the sub-pixel. The liquid crystal molecules in the TFT array will be instantaneously addressed to a predetermined optical on (ON), off (OFF), and / or gray level, where the gray level or total color is determined by a hardware ladder circuit and pulse width modulation (PWM). For example, if a ladder circuit including a series of resistors and operational amplifier ICs generates 64 voltages: v0, v1, v2, v i …v 63 and PWM provides 4 levels of Vrms, the combined gray level for each color is 256. There are three primary colors, red, green, and blue, for color reproduction, so the total number of colors in the display will exceed 16 million. The bias voltage v i (i = 0 to 63) represents the gray level voltage according to curve γ2, and the values of the resistors are determined by γ2 correction to achieve a linear gray level for the human eye.

[0096] 3. Frame Sorting

[0097] When displaying the current image, the next frame data is restored from the frame buffer transmitted from the shift register and DA (digital-to-analog) converter. To cancel the DC (Direct Current) component, frame-to-frame or line-to-line inversion can be used in the driving scheme, and the frame rate can be in the range of 30 to 140 frames per second (FPS), and most preferably the frame rate is 60 to 100 FPS. It should be noted that this driving device operates in the field-induced nematic state without phase changes and relaxations as in the prior art monostable displays.

[0098] 4. Dual-Mode Conversion

[0099] When the non-steady-state video display switches to the bistable display, a control signal is sent to the frame buffer to lock a predetermined image, the ladder circuit is switched from curve γ2 (V3 < V ≤ V4) to curve γ1 (V1 < V ≤ V2), and all liquid crystal pixels are simultaneously set from the field-induced nematic state to the cholesteric planar state via the fast path, and the display will be ready to address the specified static image.

[0100] Therefore, all levels of the analog signal with voltage levels within the range of curve γ1 (V1 < V ≤ V2) are sorted by line-to-line scanning controlled by the TFT gate signal and latched to each individual TFT source of the sub-pixel. Instantaneously, the liquid crystal and / or gray level, gray level or total color is determined by a hardware ladder circuit and PWM. For example, if a ladder circuit including a series of resistors and operational amplifier ICs generates 64 voltages: v’0, v’1, v’2, v’ i …v’ 63 and PWM provides 4 levels of Vrms, the total number of colors will exceed 16 million. The bias voltage v’ i (i = 0 to 63) represents the gray level voltage according to curve γ1, and the values of the resistors are determined by γ1 correction to achieve a linear gray level for the human eye. Once the data addressing of the final row is completed, the image is fixed by suddenly and simultaneously switching all sub-pixels to zero voltage. Finally, the zero-field bistable image will be recognized by the observer.

[0101] Obviously, curves γ1 and γ2 are different (v’ i ≠v i ), the former is positive while the latter is negative. For example, given a certain display transmittance T 50 , there are two voltages respectively derived from the ladder circuit V γ2 and V γ1 , the first is for video speed non-steady-state addressing, and the second is for static bistable image addressing.

[0102] The dual-mode display allows a wide range of frame rate modulation from 0 to 140 FPS, which is better than any other currently available displays, including electronic ink (E-ink) displays, organic light-emitting diode (OLED) displays, and ordinary liquid crystal displays (LCDs). The zero FPS full-color display is an ideal display for new e-books, where low power consumption, no flicker, and low eye fatigue are the key parameters that end-users care about. In addition, the 140 FPS display meets the standards of game displays and ultra-high-speed video displays, and will be a watershed in the development of advanced display technologies, representing a new trend in the information industry.

[0103] Turning now to Figure 6, which shows a subpixel image of a dual-light TFT design, the yellow inverted "U"-shaped pattern is the capacitor region 601, and the black light-shielding layer is the region BM. The capacitor is composed of three thin film layers: an aluminum electrode as the bottom layer connected to the gate line, silicon nitride as the middle dielectric layer, and transparent conductive ITO as the top conductor. In traditional backlight TFT designs, the entire capacitor area is covered by a black mask located on top of the display substrate. The central green rectangular area is the area covered by the CF, which allows backlight to pass through. It is not difficult to see that the yellow storage capacitor area occupies more than 50% of the green CF area. In this case, the traditional aperture ratio, defined by the ratio of the green area to the pixel area, is only 37.18%.

[0104] On the other hand, the new TFT design of the present invention utilizes a color filter film on the top substrate of the display to substantially cover the storage capacitor area 601, thereby creating a second displayable area and achieving a modified aperture ratio (MAR) greater than or equal to 55%, for example, 55%-75%, which is at least 15% larger than the conventional aperture ratio. For example, the modified aperture ratio of the present invention reaches 55.63%, thereby expanding the effective display area by 18.45%. The aperture ratio of a display is related to resolution. The higher the resolution, the lower the aperture ratio of the display. Based on the design principles of conventional TFTs, the conventional aperture ratio is generally between 40% and 60%.

[0105] 7, which illustrates switching between a video astable display mode and a powerless bi-stable display mode, wherein the horizontal axis represents time and the vertical axis represents the frame rate defined by frames per second (FPS). The video display is addressed at 60 FPS, while the powerless bi-stable display operates at 0 FPS.

[0106] As shown in Figure 7, the dual-state display starts with a 60FPS video motion picture until it reaches the "T1" moment, at which time the driving voltage waveform switches it to a bi-stable picture that reflects the last frame of data of the previous motion picture. The T1-T2 interval can be a power-free and flicker-free reading time, and the static image can be maintained for a long time. Then, from the "T2" moment to the "T3" moment, the video picture is restored again, which can be controlled by a predetermined program or by a momentary interruption (such as touch panel input). The T3-T4 interval is the second reading cycle, and the two display modes can be switched alternately thereafter. Video streaming and reading are equally important. The former is an alternative to file downloading and online browsing. It is the process by which the end user obtains the file of the content before watching or reading the content. The static picture during the above alternation can be displayed as a picture that follows it.

[0107] Turning now to Figure 8, it shows the first still color frame of the motion video titled "Apricot's Life," when the video stream is interrupted at 33 seconds. According to the time sequence shown in Figure 7, T1 = 33 seconds, T2 = 43 seconds. In other words, the duration of the first motion frame is 33 seconds, and the duration of the first still frame is 10 seconds.

[0108] Turning now to Figure 9, it shows a second still color frame of the motion video titled "Apricot's Life" when the video stream is interrupted at 1 minute 53 seconds, where T3 = 113 seconds, T4 = 123 seconds, and the entire video recording lasts 4 minutes.

[0109] Although the present invention and its advantages have been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.

Claims

1. A dual - light video cholesteric display, comprising: a. A transparent conductive front substrate having a color filter layer, and b. A first circular polarizer layer, and c. A cholesteric liquid crystal layer having at least one field - induced vertical alignment region and at least one field - induced vortex alignment region, and d. An active matrix back substrate having a first display window region and a second display window region, and e. A second circular polarizer layer, and f. A backlight surface, and g. A front - light surface, wherein the transparent conductive front substrate together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate together with the second circular polarizer layer are juxtaposed to form a display structure; wherein the backlight beam from the backlight surface passing through the first display window region and the field - induced vortex alignment region is modulated into depolarized light to form an optically - on state having at least one gray level; the backlight passing through the first display window region and the field - induced vertical alignment region is absorbed by the first circular polarizer layer and the second circular polarizer layer to form an optically - off state; wherein the front - light beam from the front - light surface reflected from the second display window region of the active matrix back substrate through the field - induced vortex alignment region is modulated into depolarized light to form an optically - on state having at least one gray level; the front - light reflected from the second display window region through the field - induced vertical alignment region is absorbed by the first circular polarizer layer to form an optically - off state; wherein the field - induced vertical alignment region and the field - induced vortex alignment region can be instantaneously interchanged at video frequencies, whereby a viewer will observe high - brightness video - rate full - color moving images under indoor and outdoor environmental conditions.

2. The dual-mode video cholesteric display according to claim 1, wherein, The first circular polarizer layer and the second circular polarizer layer have opposite polarities.

3. The dual-vision video cholesteric display according to claim 1, wherein, The first display window region is a conventional transmission region of the active matrix.

4. The dual-vision video cholesteric display according to claim 1, wherein, The second display window region is the reflective metal electrode region of the storage capacitor of the active matrix.

5. The dual-mode video cholesteric display according to claim 1, wherein, High - brightness display under indoor and outdoor environmental conditions means that in a dark environment, the backlight is the main light source, while in outdoor conditions, the front - light is the main light source.

6. The dual-mode video cholesteric display according to claim 5, wherein, The display is a transmissive display in a dark environment.

7. The dual-mode video cholesteric display according to claim 5, wherein, The display is a transflective display in an outdoor environment.

8. The dual-mode video cholesteric display according to claim 1, wherein, The display is a reflective display under daylight conditions.

9. The dual-mode video cholesteric display according to claim 1, wherein, The video speed of the display is in the range of 30 FPS to 140 FPS.

10. A dual - light static cholesteric display, comprising: a. A transparent conductive front substrate having a color filter layer, and b. A first circular polarizer layer, and c. A cholesteric liquid crystal layer having at least one cholesteric planar texture region and at least one cholesteric focal - conic texture region, and d. An active matrix back substrate having a first display window region and a second display window region, and e. A second circular polarizer layer, and f. A backlight surface, and g. A front - light surface, wherein the transparent conductive front substrate together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate together with the second circular polarizer layer are juxtaposed to form a display structure; Among them, the backlight beam from the backlight surface passing through the first displayable window area and the cholesteric focal conic texture area is modulated into depolarized light to form an optically on state with at least one gray level; the backlight passing through the first displayable window area and the cholesteric planar texture area is absorbed by the first circular polarizer layer and the second circular polarizer layer to form an optically off state; Among them, the frontlight beam from the frontlight surface reflected from the second displayable window area of the active matrix back substrate through the cholesteric focal conic texture area is modulated into depolarized light to form an optically on state with at least one gray level; the frontlight reflected from the second displayable window area through the cholesteric planar texture area is absorbed by the first circular polarizer layer to form an optically off state, whereby a viewer will observe a high-brightness, power-free and flicker-free image under indoor and outdoor environmental conditions.

11. The dual-mode static cholesteric display according to claim 10, wherein, The optically off state in the second displayable window area is caused by a 180° phase shift of the reflective metal electrode area of the storage capacitor of the active matrix.

12. The dual-mode static cholesteric display according to claim 10, wherein, The optically off state in the first displayable window area is caused by the circular polarization guiding effect of the cholesteric planar texture area.

13. The dual-mode static cholesteric display according to claim 10, wherein, The optically on states in the first displayable window area and the second displayable window area are caused by the depolarization effect of the cholesteric focal conic texture area.

14. The dual-mode static cholesteric display according to claim 10, wherein, The sum of the areas of the first displayable window area and the second displayable window area is the numerator of the modified aperture ratio of the dual-light static cholesteric display.

15. The dual-mode static cholesteric display according to claim 10, wherein, The modified aperture ratio of the dual-light static cholesteric display is greater than or equal to 55%.

16. A dual-light dual-state cholesteric display, comprising: a. A transparent conductive front substrate having a color filter layer, and b. A first circular polarizer layer, and c. A cholesteric liquid crystal layer having at least one field-induced vertical alignment area in a non-steady state and at least one field-induced vortex alignment area in a non-steady state, and at least one cholesteric planar texture area in a bistable state and at least one cholesteric focal conic texture area in a bistable state, and d. An active matrix back substrate, and e. A second circular polarizer layer, and f. A backlight surface, and g. A frontlight surface, wherein the conductive front color filter substrate together with the first circular polarizer layer, the cholesteric liquid crystal layer, and the active matrix back substrate together with the second circular polarizer layer are juxtaposed to form a display structure; wherein the beam from the backlight surface passing through the field-induced vortex alignment area and / or passing through the cholesteric focal conic texture area is modulated into depolarized light to form an optically on state; wherein the light passing through the field-induced vertical alignment area and / or the cholesteric planar texture area is absorbed by the first circular polarizer layer and the second circular polarizer layer to form an optically off state; wherein the beam from the frontlight surface reflected from the metal electrode through the field-induced vortex alignment area and / or through the cholesteric focal conic texture area is modulated into polarized light to form an optically on state; Among them, the light reflected from the metal electrode through the field-induced vertically aligned region and / or the cholesteric planar texture region is absorbed by the first circular polarizer layer to form an optically off state, whereby a viewer will observe a video display and a static display in indoor and outdoor environments, respectively.

17. The dual-mode dual-optical-chirality cholesteric display according to claim 16, wherein, The video display state and the static display state are controllable cholesteric display states.

18. The dual-mode dual-wavelength cholesteric display according to claim 16, wherein, The video display is a dynamic browsing mode display.

19. The dual-mode dual-wavelength cholesteric display according to claim 16, wherein, The static display is a static power-free and flicker-free reading and learning mode display.

20. The dual - wavelength and dual - state cholesteric display according to claim 16, wherein, The optical on and off effects are caused by the polarization and depolarization effects of cholesteric molecules.

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