Reflective display device

Abstract

The utility model discloses a kind of reflective display devices, reflective display device includes bistable liquid crystal box and substrate at the side of bistable liquid crystal box away from external environment;Bistable liquid crystal box includes opposing substrate, array substrate and bistable liquid crystal layer, the bistable liquid crystal molecule of bistable liquid crystal layer is all reflected non-visible light when reflecting state, transparent pixel electrode is equipped on array substrate, transparent common electrode is equipped on opposing substrate;Substrate includes semi-transparent half-reflection layer and black bottom layer of mutually laminated arrangement, semi-transparent half-reflection layer is located at the side of black bottom layer towards bistable liquid crystal box. By using the bistable liquid crystal molecule of reflected non-visible light, different haze fog state of bistable liquid crystal molecule can be presented by control, so that pixel can realize different brightness gray scale display;Again half-reflection layer and black bottom layer are matched, when bright state, semi-transparent half-reflection layer can also reflect part of light, can increase the reflectivity of light, improve display brightness.

Description

Technical Field

[0001] This utility model relates to the field of display technology, and in particular to a reflective display device. Background Technology

[0002] Display panels offer advantages such as thinness, durability, and low power consumption, which are energy-efficient and environmentally friendly. However, they require a backlight, resulting in a thicker module and higher cost. Electronic paper displays (reflective displays) have emerged as a solution to meet the needs of the general public. Unlike LCD displays, which require a backlight, electronic paper displays can use external light sources to display images. Therefore, even in strong sunlight, the information on the electronic paper remains clearly visible without viewing angle issues. Furthermore, due to their energy efficiency, high reflectivity, and high contrast ratio, electronic paper displays are now widely used in e-readers (such as e-books and e-newspapers) and other electronic components (such as price tags).

[0003] Existing electronic paper displays typically employ E-Ink microcapsule technology (microcapsule electronic ink technology), SiPix microcup technology (microcup electrophoretic display technology), Bridgestone electronic liquid powder technology, bistable liquid crystal display (CLCD) technology, microelectromechanical systems (MEMS) technology, or electrowetting technology. However, existing electronic paper display technologies are less mature than liquid crystal display technologies, have lower mass production efficiency, higher manufacturing costs, and cannot achieve color display.

[0004] Figure 1 This is a schematic diagram of the structure of a reflective display device using a single-layer bistable liquid crystal cell in the prior art, such as... Figure 1 As shown, existing reflective display devices using bistable liquid crystals suffer from limitations due to the pitch requirements of bistable liquid crystals. A single-pitch bistable liquid crystal can only reflect one color while transmitting other colors of light. Therefore, single-layer bistable liquid crystal reflective display devices mostly display in formats such as yellow background with black text, black background with yellow text, black background with red text, or red background with black text, failing to achieve displays like black background with white text or white background with black text, which significantly limits product applications. Furthermore, the color of the reflected light from bistable liquid crystals is poor, affecting the display effect. Figure 2 This is a schematic diagram of the structure of a reflective display device using a three-layer bistable liquid crystal cell in the prior art, such as... Figure 2As shown, to achieve white or color display, a reflective display device needs to use a three-layer bistable liquid crystal cell to reflect red, green, and blue light respectively, thus achieving white and color display. However, the three-layer bistable liquid crystal cell is not only thicker but also more expensive. If a double-sided reflective display is required, the cell thickness of the display device will be even greater, which is not conducive to the development of thinner and lighter display devices.

[0005] Because bistable liquid crystals require voltage to maintain in the H state, resulting in high power consumption, existing bistable liquid crystal display devices typically only control the switching between the P and FC states. This not only results in low reflectivity but also a limited number of gray levels, leading to a smaller number of colors that can be displayed and a lower NTSC. Utility Model Content

[0006] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a reflective display device to solve the problem of low reflectivity in the existing bistable liquid crystal display device.

[0007] The objective of this utility model is achieved through the following technical solution: This utility model provides a reflective display device, including a bistable liquid crystal cell and a substrate disposed on the side of the bistable liquid crystal cell away from the external environment; The bistable liquid crystal cell includes an opposing substrate, an array substrate disposed opposite to the opposing substrate, and a bistable liquid crystal layer located between the opposing substrate and the array substrate. The bistable liquid crystal layer contains bistable liquid crystal molecules, all of which reflect non-visible light in the reflective state. The array substrate is provided with transparent pixel electrodes, and the opposing substrate is provided with transparent common electrodes that cooperate with the transparent pixel electrodes. The substrate includes a semi-transparent and semi-reflective layer and a black substrate stacked on top of each other, with the semi-transparent and semi-reflective layer disposed on the side of the black substrate facing the bistable liquid crystal cell.

[0008] Furthermore, the semi-transparent and semi-reflective layer includes an APF film, a DBEF film, a reflective metal film, a metal wire grid polarizer, or a multi-refractive-index oxide layer.

[0009] Furthermore, the reflective metal film includes a reflective metal and a light-transmitting area, wherein the reflective metal is a strip-shaped structure or a mesh-shaped structure.

[0010] Furthermore, the multi-refractive-index oxide layer includes silicon oxide layers, titanium oxide layers, and / or niobium oxide layers stacked on top of each other.

[0011] Furthermore, the black underlayer includes a black ink layer, a black Mylar film, a black metal oxide layer, or an orthogonal dual polarizer.

[0012] Furthermore, the black metal oxide layer includes a molybdenum oxide layer; The orthogonal dual polarizer includes a first polarizer and a second polarizer, which are perpendicular to each other.

[0013] Furthermore, the array substrate is disposed on the side of the bistable liquid crystal cell facing the substrate; or, the opposing substrate is disposed on the side of the bistable liquid crystal cell facing the substrate.

[0014] Furthermore, the bistable liquid crystal cell has multiple pixel units arranged in an array, each pixel unit having a corresponding transparent pixel electrode, and the opposing substrate having a color resist layer in the area corresponding to each pixel unit.

[0015] Furthermore, the plurality of pixel units include green pixel units, blue pixel units, and red pixel units, and the color resist layer includes a green resist layer, a blue resist layer, and a red resist layer, wherein the green resist layer corresponds to the green pixel unit, the blue resist layer corresponds to the blue pixel unit, and the red resist layer corresponds to the red pixel unit.

[0016] Furthermore, the opposing substrate is provided with a black matrix, which separates the plurality of pixel units from each other.

[0017] The beneficial effects of this invention are as follows: by using bistable liquid crystal molecules that reflect non-visible light, the bistable liquid crystal molecules can be controlled to present different levels of haze, enabling pixels to achieve grayscale display with different brightness. The haze of the bistable liquid crystal molecules can be adjusted by the driving voltage, allowing pixels to achieve more grayscale levels. Furthermore, when combined with a semi-transparent and semi-reflective layer and a black base layer, the semi-transparent and semi-reflective layer can also reflect some light in the bright state, which can increase the reflectivity of light and improve the display brightness. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a reflective display device using a single-layer bistable liquid crystal cell in the prior art.

[0019] Figure 2 This is a schematic diagram of the structure of a three-layer bistable liquid crystal cell used in existing reflective display devices.

[0020] Figure 3 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 1 of this utility model.

[0021] Figure 4 This is a schematic diagram of the arrangement structure of the color resist on the opposing substrate in Embodiment 1 of this utility model.

[0022] Figure 5 This is a schematic diagram of the planar structure of the array substrate in Embodiment 1 of this utility model.

[0023] Figure 6 This is a schematic diagram illustrating the principle of bistable liquid crystal molecule state transformation in Embodiment 1 of this utility model.

[0024] Figure 7 This is a schematic diagram of the driving signals corresponding to the state transitions of bistable liquid crystal molecules in Embodiment 1 of this utility model.

[0025] Figure 8 This is a schematic diagram of the reflective display device in Embodiment 1 of this utility model when displaying a black screen.

[0026] Figure 9 This is a schematic diagram of the driving signal of the reflective display device in Embodiment 1 of this utility model at low grayscale brightness.

[0027] Figure 10 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of this utility model when displaying a color image at low grayscale brightness.

[0028] Figure 11 This is a schematic diagram of the driving signal of the reflective display device in Embodiment 1 of this utility model at high grayscale brightness.

[0029] Figure 12 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of this utility model when displaying a color image at high grayscale brightness.

[0030] Figure 13 This is one of the structural schematic diagrams of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model.

[0031] Figure 14 This is the second schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model.

[0032] Figure 15 This is the third schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model.

[0033] Figure 16 This is the fourth schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model.

[0034] Figure 17 This is a schematic diagram of the black bottom layer in Embodiment 3 of this utility model.

[0035] Figure 18 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 4 of this utility model.

[0036] Figure 19This is a schematic diagram of the reflective display device in its initial state in Embodiment 5 of this utility model. Detailed Implementation

[0037] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation methods, structure, features, and effects of the reflective display device proposed according to this utility model: [Example 1] Figure 3 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 1 of this utility model. Figure 4 This is a schematic diagram of the arrangement structure of the color resist on the opposing substrate in Embodiment 1 of this utility model. Figure 5 This is a schematic diagram of the planar structure of the array substrate in Embodiment 1 of this utility model.

[0038] like Figures 3 to 5 As shown in Embodiment 1 of this utility model, a reflective display device includes a bistable liquid crystal cell 10 and a substrate 20 disposed on the side of the bistable liquid crystal cell 10 away from the external environment. The substrate 20 can be bonded to the bistable liquid crystal cell 10 with a transparent adhesive (e.g., OCA adhesive). The substrate 20 includes a transflective layer 21 and a black substrate 22 stacked on top of each other. The transflective layer 21 is disposed on the side of the black substrate 22 facing the bistable liquid crystal cell 10. The transflective layer 21 can reflect some light and transmit some light, while the black substrate 22 can absorb the light passing through the transflective layer 21, thereby enabling the reflective display device to achieve a black state and improving display quality.

[0039] In this embodiment, the semi-transparent and semi-reflective layer 21 can be an APF (Advanced Polarizing Film), i.e., a brightness enhancement polarizer. An APF film has mutually perpendicular reflective and transmission axes, allowing it to reflect light parallel to the reflective axis and transmit light parallel to the transmission axis. Of course, in other embodiments, the semi-transparent and semi-reflective layer 21 can also be a DBEF (Dual Brightness Enhancement Film), i.e., a brightness enhancement film, which can reflect some light and transmit some light. The reflection angle of the semi-transparent and semi-reflective layer 21 can be set to a large viewing angle (e.g., a viewing angle greater than 65°, with the viewing angle perpendicular to the display device being 0° and the viewing angle parallel to the display device being 90°), meaning that ambient light is reflected towards the large viewing angle, thereby reducing the impact on black states. For example, a prism structure can be provided on the semi-transparent and semi-reflective layer 21 to achieve the goal of reflecting ambient light towards the large viewing angle.

[0040] In this embodiment, the black base layer 22 is a black ink layer with an L value (representing brightness) greater than 25 and an OD value (optical density) greater than 4, thus giving the black base layer 22 high blackness and good gloss, ensuring a deeper black in the image. Of course, the black base layer 22 can be made of BM material or black opaque adhesive. Alternatively, in other embodiments, the black base layer 22 can also be made of black Mylar film (Mylar film is an insulating material made from PET polyester film as the base material, possessing excellent electrical insulation properties, mechanical strength, and chemical corrosion resistance; its appearance can be divided into various types such as milky white, black, and transparent), or the black base layer 22 can also be made of a black metal oxide layer, such as a molybdenum oxide (MoOx) layer.

[0041] The bistable liquid crystal cell 10 includes a counter substrate 11, an array substrate 12 disposed opposite to the counter substrate 11, and a bistable liquid crystal layer 13 located between the counter substrate 11 and the array substrate 12. The bistable liquid crystal layer 13 contains bistable liquid crystal molecules 131, all of which reflect non-visible light in the reflective state. In this embodiment, the array substrate 12 is disposed on the side of the bistable liquid crystal cell 10 facing the substrate 20, that is, the array substrate 12 is disposed on the side of the bistable liquid crystal cell 10 away from the external environment, and the counter substrate 11 is disposed on the side of the bistable liquid crystal cell 10 facing the external environment.

[0042] The bistable liquid crystal cell 10 has multiple pixel units P arranged in an array. A transparent pixel electrode 121 is provided on the array substrate 12, and a transparent common electrode 111 that cooperates with the transparent pixel electrode 121 is provided on the opposing substrate 11. A color resist layer 113 is provided in the area corresponding to each pixel unit P. Each pixel unit P has a corresponding transparent pixel electrode 121 and a color resist layer 113. The transparent pixel electrode 121 is a block electrode that corresponds one-to-one with each pixel unit P, and the transparent common electrode 111 is a planar electrode that covers the entire opposing substrate 11. The transparent pixel electrode 121 and the transparent common electrode 111 cooperate with each other and control the deflection of the bistable liquid crystal molecules 131 in the bistable liquid crystal layer 13, thereby controlling the bistable liquid crystal molecules 131 to present a hazy state with different degrees of haze, so as to achieve different grayscale brightness. The transparent pixel electrode 121 is disposed on the side of the array substrate 12 closest to the bistable liquid crystal layer 13, and the transparent common electrode 111 is disposed on the side of the opposing substrate 11 closest to the bistable liquid crystal layer 13, so as to improve the response speed of the bistable liquid crystal layer 13.

[0043] When pixel unit P is in a bright state, the bistable liquid crystal molecules 131 in the corresponding area of ​​pixel unit P are in a disordered tilted state, making the bistable liquid crystal molecules 131 in the corresponding area of ​​pixel unit P a fog state. By controlling the bistable liquid crystal molecules 131 to present different levels of fog, different grayscale brightness can be achieved by pixel unit P. When pixel unit P is in a dark state, the bistable liquid crystal molecules 131 in the corresponding area of ​​pixel unit P are in a flat position, making the bistable liquid crystal molecules 131 in the corresponding area of ​​pixel unit P a reflective state. The bistable liquid crystal molecules 131 reflect non-visible light. Visible light in the ambient light is absorbed by the color resist layer 113 and the black bottom layer 22 to present black. That is, black can be achieved without controlling the bistable liquid crystal molecules 131 to be in the H state (transparent state). In the bright state, the transflective layer 21 can also reflect some light, increasing the reflectivity and improving display brightness. At this time, since the bistable liquid crystal molecules 131 are in a foggy state, they scatter the light reflected by the transflective layer 21, thus improving brightness from all viewing angles. In the dark state, because the bistable liquid crystal molecules 131 are reflective to non-visible light and transparent to visible light, meaning they have no scattering effect on visible light, the transflective layer 21 only reflects in one specific direction, essentially having no impact on the dark state effect.

[0044] Among them, bistable liquid crystal molecules possess three stable textures: P-state (Planar, reflective state), FC-state (Focal-Conic, hazy state), and H-state (transparent state). In the P-state, the reflection spectrum of the bistable liquid crystal molecule is in the non-visible spectral range; the bistable liquid crystal molecule reflects non-visible light, and the specific reflected light can be set according to the pitch of the bistable liquid crystal molecule, with the reflected wavelength satisfying the condition λ = n*P (λ is wavelength, P is pitch, and n is refractive index). In the FC-state, the bistable liquid crystal molecule no longer reflects the aforementioned light, and light can be scattered and passed through the bistable liquid crystal molecule. In the H-state, the bistable liquid crystal molecule also no longer reflects the aforementioned light, and light can pass directly through the bistable liquid crystal molecule without any scattering effect. Under the influence of a certain electric field, these three states can interconvert. A bistable liquid crystal molecule is, for example, a cholesteric liquid crystal molecule.

[0045] Figure 6 This is a schematic diagram illustrating the principle of bistable liquid crystal molecule state transformation in Embodiment 1 of this utility model. Figure 7 This is a schematic diagram of the driving signals corresponding to the state transitions of bistable liquid crystal molecules in Embodiment 1 of this utility model. For example... Figure 6 and Figure 7As shown, a common voltage signal Vcom is applied to the common electrode (transparent common electrode 111), and a first electrical signal V1 is continuously applied to the pixel electrode (transparent pixel electrode 121). There is a first voltage difference (approximately 20V) between the common voltage signal Vcom and the first electrical signal V1. A strong vertical electric field is formed between the common electrode and the pixel electrode, causing the bistable liquid crystal molecules to rotate and remain in the H state (transparent state). The common voltage signal Vcom is then applied to the common electrode, and a second electrical signal V2 is applied to the pixel electrode. There is a second voltage difference (e.g., 30V) between the second electrical signal V2 and the common voltage signal Vcom. The second electrical signal V2 directly becomes the same as the common voltage signal Vcom at a first preset time. That is, the second electrical signal V2 initially has a large voltage difference with the common voltage signal Vcom, then rapidly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the common electrode and the pixel electrode, and then the vertical electric field rapidly disappears, causing the bistable liquid crystal molecules to first rotate to the H state, and then rotate and remain in the P state, which is the reflective state. A common voltage signal Vcom is applied to the common electrode, and a third electrical signal V3 is applied to the pixel electrode. There is a first voltage difference (e.g., 20V) between the third electrical signal V3 and the common voltage signal Vcom. The third electrical signal V3 gradually becomes the same as the common voltage signal Vcom within a second preset time. That is, the third electrical signal V3 first has a large voltage difference with the common voltage signal Vcom, and then slowly decreases and becomes the same as the common voltage signal Vcom. The first preset time is less than the second preset time. Therefore, a strong vertical electric field is first formed between the common electrode and the pixel electrode. Then the vertical electric field slowly disappears, causing the bistable liquid crystal molecules to first rotate into the H state, and then rotate and stagnate in the high haze FC state. This is a scattering state and has a light-scattering effect. Alternatively, a common voltage signal Vcom can be applied to the common electrode, and a fourth electrical signal V4 can be applied to the pixel electrode. The fourth electrical signal V4 initially has a second voltage difference (e.g., 30V) with the common voltage signal Vcom. At a third preset time, the fourth electrical signal V4 directly becomes the same as the common voltage signal Vcom. Then, the fourth electrical signal V4 again has a first voltage difference (e.g., 20V) with the common voltage signal Vcom, and gradually becomes the same as the common voltage signal Vcom at a fourth preset time. That is, the fourth electrical signal V4 initially has a voltage difference with the common voltage signal Vcom. m has a large voltage difference, which decreases rapidly and becomes the same as the common voltage signal Vcom. Then it is boosted to a smaller voltage difference with the common voltage signal Vcom, which decreases rapidly and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the pixel electrode and the common electrode. The vertical electric field disappears rapidly. Then a weaker vertical electric field is formed between the pixel electrode and the common electrode. The vertical electric field disappears rapidly. This causes the bistable liquid crystal molecules to first rotate to the H state, then rotate to the P state, and finally rotate and stagnate in the low haze FC state. This is a scattering state and has a light-scattering effect.Compared to the third electrical signal V3, the fourth electrical signal V4 drives the bistable liquid crystal molecules to the FC state with lower haze and better light transmission. Of course, the haze of the bistable liquid crystal molecules in the hazy state can also be controlled by adjusting the amplitude of the third electrical signal V3 or the fourth electrical signal V4 to achieve different grayscale brightness levels. The different arrangement directions of the bistable liquid crystal molecules result in different reflected visible light spectra, with the remaining spectrum transmitted. The P-state and FC state do not require voltage to maintain.

[0046] In this embodiment, the bistable liquid crystal molecule 131 is an infrared bistable liquid crystal molecule that reflects infrared light in its reflective state, meaning the primary reflection wavelength is above 800nm. According to λ=n*p, when the refractive index n is 1.6, the corresponding pitch is >500nm. Alternatively, the bistable liquid crystal molecule 131 can be an ultraviolet bistable liquid crystal molecule that reflects ultraviolet light in its reflective state, meaning the primary reflection wavelength is below 400nm. According to λ=n*p, when the refractive index n is 1.6, the corresponding pitch is <250nm. This allows the bistable liquid crystal molecule 131 to reflect light invisible to the human eye in its reflective state, while visible light is absorbed by the color resist layer 113 and the black substrate 22, achieving a black state effect.

[0047] In this embodiment, the multiple pixel units P include green pixel units, blue pixel units, and red pixel units. The color resist layer 113 includes a green resist layer 113a, a blue resist layer 113b, and a red resist layer 113c. The green resist layer 113a corresponds to the green pixel unit, the blue resist layer 113b corresponds to the blue pixel unit, and the red resist layer 113c corresponds to the red pixel unit. This allows the reflective display device to display various colors based on the color mixing principle of red / green / blue light. Furthermore, by combining this with the multiple grayscale brightness levels of the pixel units P, a richer range of colors can be displayed. For example, Figure 4 As shown, a column of green pixel units, a column of blue pixel units, and a column of red pixel units are arranged alternately along the row direction.

[0048] like Figure 5As shown, the array substrate 12 has multiple scan lines 101 and multiple data lines 102. The multiple scan lines 101 and multiple data lines 102 are mutually insulated and intersecting to form multiple pixel units P. Each pixel unit P has a thin-film transistor 103 and a transparent pixel electrode 121. The transparent pixel electrode 121 is electrically connected to the scan lines 101 and data lines 102 adjacent to the thin-film transistor 103 through the thin-film transistor 103. The thin-film transistor 103 includes a gate, an active layer, a drain, and a source. The gate and the scan lines 101 are located on the same layer and are electrically connected. The gate and the active layer are isolated by an insulating layer. The source is electrically connected to the data lines 102. The drain is electrically connected to the transparent pixel electrode 121 through a contact hole.

[0049] Furthermore, a black matrix 112 is provided on the opposing substrate 11. The black matrix 112 separates multiple pixel units P from each other. Specifically, the black matrix 112 on the opposing substrate 11 separates the green color resist layer 113a, the blue color resist layer 113b, and the red color resist layer 113c from each other, thereby avoiding color mixing between adjacent pixel units P. The projection of the black matrix 112 on the array substrate 12 corresponds to the scan line 101, the data line 102, and the thin-film transistor 103, thereby aligning the scan line 101, the data line 102, and the thin-film transistor 103 and providing a light-shielding effect.

[0050] The opposing substrate 11 and the array substrate 12 can be made of transparent substrates such as glass, acrylic, and polycarbonate. The transparent common electrode 111 and the transparent pixel electrode 121 can be made of transparent electrodes such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0051] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above. The driving method includes: In the dark state, a common signal voltage is applied to the transparent common electrode 111 and a reflective state voltage is applied to the transparent pixel electrode 121 to control the bistable liquid crystal molecule 131 to present a reflective state. Since the bistable liquid crystal molecule 131 reflects non-visible light, the visible light in the ambient light is absorbed by the color resist layer 113 and the black bottom layer 22 to present black. That is, black can be achieved without controlling the bistable liquid crystal molecule 131 to be in the H state (transparent state).

[0052] In the bright state, a common signal voltage is applied to the transparent common electrode 111, and a hazy grayscale voltage is applied to the transparent pixel electrode 121 to control the bistable liquid crystal molecules 131 to exhibit different degrees of haze. Figure 8 This is a schematic diagram of the reflective display device in Embodiment 1 of this utility model when displaying a black screen. Figures 6 to 8As shown, when displaying a black screen, a common voltage signal Vcom is applied to the transparent common electrode 111, and a second electrical signal V2 is applied to the transparent pixel electrode 121. There is a second voltage difference (e.g., 30V) between the second electrical signal V2 and the common voltage signal Vcom. The second electrical signal V2 directly becomes the same as the common voltage signal Vcom at a first preset time. That is, the second electrical signal V2 first has a large voltage difference with the common voltage signal Vcom, and then rapidly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the transparent common electrode 111 and the transparent pixel electrode 121. Then the vertical electric field disappears rapidly, causing the bistable liquid crystal molecules to first rotate to the H state, and then rotate and stagnate in the P state, which is a reflective state. The bistable liquid crystal molecules 131 reflect non-visible light. Ambient light is absorbed by the color resist layer 113 and the black bottom layer 22 to present black.

[0053] Figure 9 This is a schematic diagram of the driving signal of the reflective display device in Embodiment 1 of this utility model at low grayscale brightness. Figure 10 This is a schematic diagram of the reflective display device in Embodiment 1 of this utility model when displaying a color image at low grayscale brightness. Figure 9 and Figure 10 As shown, at low grayscale brightness, a common voltage signal Vcom is applied to the transparent common electrode 111, and a fourth electrical signal V4 is applied to the transparent pixel electrode 121. The fourth electrical signal V4 initially has a second voltage difference (e.g., 30V) with the common voltage signal Vcom. At a third preset time, the fourth electrical signal V4 directly becomes the same as the common voltage signal Vcom. Then, the fourth electrical signal V4 again has a first voltage difference (e.g., 20V) with the common voltage signal Vcom, and gradually becomes the same as the common voltage signal Vcom at a fourth preset time. That is, the fourth electrical signal V4 initially has a voltage difference (e.g., 20V) with the common voltage signal Vcom. The voltage difference of com is large, which decreases rapidly and becomes the same as the common voltage signal Vcom. Then it is boosted to a smaller voltage difference with the common voltage signal Vcom, which decreases rapidly and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the transparent pixel electrode 121 and the transparent common electrode 111. The vertical electric field disappears rapidly. Then a weaker vertical electric field is formed between the transparent pixel electrode 121 and the transparent common electrode 111. The vertical electric field disappears rapidly, causing the bistable liquid crystal molecules to first rotate to the H state, then rotate to the P state, and finally rotate and stop in the low haze FC state. This is a scattering state and has a light-scattering effect.

[0054] Figure 11 This is a schematic diagram of the driving signal of the reflective display device in Embodiment 1 of this utility model at high grayscale brightness. Figure 12 This is a schematic diagram of the reflective display device in Embodiment 1 of this utility model when displaying a color image at high grayscale brightness. Figure 11 and Figure 12 As shown, at high grayscale brightness, a common voltage signal Vcom is applied to the transparent common electrode 111, and a third electrical signal V3 is applied to the transparent pixel electrode 121. There is a first voltage difference (e.g., 20V) between the third electrical signal V3 and the common voltage signal Vcom, and the third electrical signal V3 gradually becomes the same as the common voltage signal Vcom within a second preset time. That is, the third electrical signal V3 first has a large voltage difference with the common voltage signal Vcom, and then slowly decreases and becomes the same as the common voltage signal Vcom. The first preset time is less than the second preset time. Therefore, a strong vertical electric field is first formed between the transparent common electrode 111 and the transparent pixel electrode 121, and then the vertical electric field slowly disappears, causing the bistable liquid crystal molecules to first rotate to the H state, and then rotate and stagnate in the high haze FC state. This is a scattering state and has a light-scattering effect.

[0055] Among them, the haze of bistable liquid crystal molecules in the fog state can be controlled by controlling the amplitude of the third electrical signal V3 or the fourth electrical signal V4, so as to achieve different gray level brightness. Then, according to the color mixing principle of red / green / blue light, a richer color display can be achieved.

[0056] [Example 2] Figure 13 This is one of the structural schematic diagrams of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model. Figure 14 This is the second schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model. Figure 15 This is the third schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model. Figure 16 This is the fourth schematic diagram of the semi-transparent and semi-reflective layer in Embodiment 2 of this utility model. (See diagram below.) Figures 13 to 16 As shown, the reflective display device provided in Embodiment 2 of this utility model is similar to that in Embodiment 1. Figures 3 to 12 The reflective display devices in the above are basically the same, except that: In this embodiment, the semi-transparent and semi-reflective layer 21 can also adopt other structures that have the effect of reflecting part of the light and transmitting part of the light.

[0057] like Figure 13As shown, the semi-transparent and semi-reflective layer 21 can be a metal wire grid polarizer. The metal wire grid polarizer has a special polarization characteristic: it transmits polarized light perpendicular to the extension direction of the metal wire grid and reflects polarized light parallel to the extension direction of the metal wire grid. In the incident light ray A, the light has a first polarized light a perpendicular to the extension direction of the metal wire grid and a second polarized light b parallel to the extension direction of the metal wire grid. The first polarized light a, perpendicular to the extension direction of the metal wire grid, can pass through the metal wire grid polarizer to form a transmitted light ray C, while the second polarized light b, parallel to the extension direction of the metal wire grid, will be reflected to form a reflected light ray B. For a more detailed description of the metal wire grid polarizer, please refer to existing technology; it will not be elaborated here.

[0058] like Figure 14 and Figure 15 As shown, the semi-transparent and semi-reflective layer 21 can also be a reflective metal film. The reflective metal film includes a reflective metal and a light-transmitting area. The reflective metal can be made of a metal with high reflectivity, such as aluminum or silver. The reflective metal area reflects light, while the light-transmitting area allows light to pass through. The reflective metal has a strip-like structure. Figure 14 ) or grid structure ( Figure 15 The reflectivity and transmittance of the reflective metal film can be adjusted according to the size of the light-transmitting area.

[0059] like Figure 16 As shown, the semi-transparent and semi-reflective layer 21 can also be a multi-refractive-index oxide layer, which includes a silicon oxide layer, a titanium oxide layer and / or a niobium oxide layer stacked on top of each other. The refractive indices of the silicon oxide layer, the titanium oxide layer and the niobium oxide layer are different. The reflective layer is formed by sputtering or evaporation. The thickness, combination and ratio of various oxide films are adjusted according to different needs to achieve different degrees of reflectivity and transmittance.

[0060] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0061] [Example 3] Figure 17 This is a schematic diagram of the black base layer in Embodiment 3 of this utility model. (See attached diagram.) Figure 17 As shown, the reflective display device provided in Embodiment 3 of this utility model is similar to that in Embodiment 1. Figures 3 to 12 Example 2 Figures 13 to 16 The reflective display devices in the above are basically the same, except that: In this embodiment, the black substrate 22 includes an orthogonal dual polarizer, which comprises a first polarizer and a second polarizer. The first polarizer and the second polarizer are perpendicular to each other, thereby achieving a light absorption effect. The orthogonal dual polarizer is composed of multiple TAC layers and two PVA layers, with the absorption axes of the PVA1 layer and the PVA2 layer being orthogonal.

[0062] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0063] [Example 4] Figure 18 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 4 of this utility model. Figure 18 As shown, the reflective display device provided in Embodiment 4 of this utility model is similar to that in Embodiment 1 ( Figures 3 to 12 Example 2 Figures 13 to 16 Example 3 Figure 17 The reflective display devices in the above are basically the same, except that: In this embodiment, the opposing substrate 11 is disposed on the side of the bistable liquid crystal cell 10 facing the substrate 20, that is, the opposing substrate 11 is disposed on the side of the bistable liquid crystal cell 10 away from the external environment, and the array substrate 12 is disposed on the side of the bistable liquid crystal cell 10 facing the external environment.

[0064] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, and Embodiment 3, and will not be repeated here.

[0065] [Example 5] Figure 19 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 5 of this utility model. Figure 19 As shown, the reflective display device provided in Embodiment 5 of this utility model is similar to that in Embodiment 1 ( Figures 3 to 12 Example 2 Figures 13 to 16 Example 3 Figure 17 Example 4 Figure 18 The reflective display devices in the above are basically the same, except that: In this embodiment, the opposing substrate 11 is transparent in the area corresponding to the pixel unit P, for example, by filling with a planarization layer, that is, there is no need to set a color resist layer 113, so that the reflective display device can realize black and white image display.

[0066] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4, and will not be repeated here.

[0067] In this document, the directional terms such as up, down, left, right, front, and back are defined according to the position of the structures in the accompanying drawings and the relative positions of the structures, and are only used for clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second," etc., used herein are only used for distinction in name and are not used to limit the number or order.

[0068] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present utility model. These are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A reflective display device, characterized in that, It includes a bistable liquid crystal cell (10) and a substrate (20) disposed on the side of the bistable liquid crystal cell (10) away from the external environment; The bistable liquid crystal cell (10) includes a counter substrate (11), an array substrate (12) disposed opposite to the counter substrate (11), and a bistable liquid crystal layer (13) located between the counter substrate (11) and the array substrate (12). The bistable liquid crystal layer (13) contains bistable liquid crystal molecules (131), and all the bistable liquid crystal molecules (131) reflect non-visible light in the reflective state. The array substrate (12) is provided with transparent pixel electrodes (121), and the counter substrate (11) is provided with transparent common electrodes (111) that cooperate with the transparent pixel electrodes (121). The substrate (20) includes a semi-transparent and semi-reflective layer (21) and a black bottom layer (22) stacked on each other, wherein the semi-transparent and semi-reflective layer (21) is disposed on the side of the black bottom layer (22) facing the bistable liquid crystal cell (10).

2. The reflective display device according to claim 1, characterized in that, The semi-transparent and semi-reflective layer (21) includes an APF film, a DBEF film, a reflective metal film, a metal wire grid polarizer, or a multi-refractive-index oxide layer.

3. The reflective display device according to claim 2, characterized in that, The reflective metal film includes a reflective metal and a light-transmitting area, wherein the reflective metal has a strip-shaped structure or a mesh-shaped structure.

4. The reflective display device according to claim 2, characterized in that, The multi-refractive-index oxide layer includes a silicon oxide layer, a titanium oxide layer, and / or a niobium oxide layer stacked on top of each other.

5. The reflective display device according to claim 1, characterized in that, The black underlayer (22) includes a black ink layer, a black Mylar film, a black metal oxide layer, or an orthogonal dual polarizer.

6. The reflective display device according to claim 5, characterized in that, The black metal oxide layer includes a molybdenum oxide layer; The orthogonal dual polarizer includes a first polarizer and a second polarizer, which are perpendicular to each other.

7. The reflective display device according to any one of claims 1-6, characterized in that, The array substrate (12) is disposed on the side of the bistable liquid crystal cell (10) facing the substrate (20); or, the opposing substrate (11) is disposed on the side of the bistable liquid crystal cell (10) facing the substrate (20).

8. The reflective display device according to any one of claims 1-6, characterized in that, The bistable liquid crystal cell (10) has a plurality of pixel units (P) arranged in an array, and each pixel unit (P) is provided with a transparent pixel electrode (121). The opposing substrate (11) is provided with a color resist layer (113) in the area corresponding to the pixel unit (P).

9. The reflective display device according to claim 8, characterized in that, The plurality of pixel units (P) include green pixel units, blue pixel units and red pixel units. The color resist layer (113) includes a green resist layer (113a), a blue resist layer (113b) and a red resist layer (113c). The green resist layer (113a) corresponds to the green pixel unit, the blue resist layer (113b) corresponds to the blue pixel unit, and the red resist layer (113c) corresponds to the red pixel unit.

10. The reflective display device according to claim 8, characterized in that, The opposing substrate (11) is provided with a black matrix (112), which separates the plurality of pixel units (P) from each other.

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