Display module, display device and control method thereof

Abstract

The application provides a display module, a display device and a control method thereof. The display module comprises a display panel, the display panel comprising at least a color filter, a composite functional layer and a liquid crystal layer from top to bottom; a backlight module arranged below the display panel and used for providing an illumination light source; wherein the composite functional layer is integrated between the color filter and the liquid crystal layer, and is switched between a transparent state and a state of forming a micro-optical structure by controlling the voltage applied thereto. In the display module, the composite functional layer is integrated between the color filter and the liquid crystal layer inside the display panel, and an independent anti-peeping film layer is not needed to be additionally added, thereby avoiding the increase of the thickness of the display module. Meanwhile, the composite functional layer has a high light transmittance in the transparent state, and realizes anti-peeping by limiting the light angle in the anti-peeping state of forming the micro-optical structure instead of relying on absorption, so that the light transmittance is not significantly reduced, and the display brightness loss and the increase of the backlight power consumption are avoided.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a display module, display device, and control method thereof. Background Technology

[0002] Liquid crystal displays (LCDs) are widely used in mobile phones, computers, ATMs, medical monitors, and automotive displays due to their thinness, low power consumption, and excellent image quality. Typically, LCDs are designed with a wide viewing angle to allow users to view the screen content from different angles. However, in many applications, this wide viewing angle actually poses information security risks. To address privacy concerns, various privacy protection solutions have been proposed in existing technologies. Common methods involve introducing special optical coatings or additional polarizers into the display panel to control the viewing angle by altering the polarization state of light.

[0003] However, the aforementioned existing technologies all have significant shortcomings. Adding a polarizer adds a fixed optical structure to the display panel. Once the privacy film or coating is integrated into the module, the additional coating usually increases the thickness of the display module and reduces light transmittance, resulting in a loss of display brightness and increased backlight power consumption. Furthermore, the bonding process between these additional layers and the original display panel is complex, easily introducing problems such as poor bonding, bubbles, or optical interference lines (moiré fringes), reducing product yield and reliability. Summary of the Invention

[0004] This application provides a display module, including: a display panel, which includes at least a color filter, a composite functional layer, and a liquid crystal layer from top to bottom; and a backlight module disposed below the display panel for providing an illumination source; wherein the composite functional layer is integrated between the color filter and the liquid crystal layer, and switches between a transparent state and a state of forming a micro-optical structure by controlling the voltage applied thereon.

[0005] In some embodiments, the composite functional layer comprises at least a polymer-dispersed liquid crystal material and a quantum dot material.

[0006] In some embodiments, the composite functional layer is formed by uniformly doping quantum dot materials into a polymer-dispersed liquid crystal material.

[0007] In some embodiments, the micro-optical structure is a microprism array used to focus incident light within a preset viewing angle.

[0008] In some embodiments, a transparent electrode is also included, which is disposed on both sides of the composite functional layer.

[0009] In some embodiments, a driving chip is also included, which applies or removes voltage to the transparent electrode to achieve switching between a transparent state and a state in which a micro-optical structure is formed.

[0010] In some embodiments, the transparent electrode is an ITO transparent electrode that covers the entire surface.

[0011] This application provides a display device, which includes at least the above-described display module.

[0012] This application provides a control method for a display device, comprising: detecting the voltage across both sides of a composite functional layer; controlling the composite functional layer to be in a transparent state when there is no voltage across both sides of the composite functional layer; and controlling the composite functional layer to be in a micro-optical structure state when there is voltage across both sides of the composite functional layer.

[0013] In some embodiments, controlling the state of the composite functional layer to be transparent includes controlling the light refractive index of the liquid crystal molecules in the composite functional layer to match the light refractive index of the polymer network, so that the state of the composite functional layer is transparent; controlling the state of the composite functional layer to be a micro-optical structure includes controlling the light refractive index of the liquid crystal molecules in the composite functional layer to be greater than the light refractive index of the polymer network, so that the composite functional layer is a micro-optical structure.

[0014] The display module of this application integrates a composite functional layer between the color filter and the liquid crystal layer inside the display panel, eliminating the need for an additional privacy screen protector layer and avoiding an increase in the thickness of the display module. Simultaneously, this composite functional layer exhibits high light transmittance in its transparent state, and in its privacy-protected state, which forms a micro-optical structure, privacy is achieved through light angle restriction rather than absorption. Therefore, it does not significantly reduce light transmittance, avoiding loss of display brightness and increased backlight power consumption. Attached Figure Description

[0015] Figure 1 An exemplary circuit diagram of controlling the voltage on both sides of the composite functional layer according to an embodiment of this application is shown; Figure 2 An exemplary flowchart illustrates a control method for a display device according to an embodiment of this application; Figure 3 An exemplary schematic diagram of a display device according to an embodiment of this application is shown in normal operation. Figure 4 An exemplary schematic diagram of a privacy display device according to an embodiment of this application is shown. Detailed Implementation

[0016] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to implement them more readily. Furthermore, for clarity, portions unrelated to the description of exemplary embodiments have been omitted from the drawings. In this disclosure, it should be understood that terms such as "comprising" or "having" are intended to indicate the presence of features, numbers, steps, behaviors, components, portions, or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, numbers, steps, behaviors, components, portions, or combinations thereof. It should also be noted that, without conflict, embodiments and features in the embodiments of this disclosure can be combined with each other. The present disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] This application provides a display module, including: a display panel, which includes at least a color filter, a composite functional layer, and a liquid crystal layer from top to bottom; and a backlight module disposed below the display panel for providing an illumination source; wherein the composite functional layer is integrated between the color filter and the liquid crystal layer, and switches between a transparent state and a state of forming a micro-optical structure by controlling the voltage applied thereon.

[0018] For example, the display panel of the display module is a liquid crystal display panel, which includes, from top to bottom (i.e. from the light-emitting side to the backlight module side): an upper polarizer, an upper substrate, a black matrix, a color filter, a composite functional layer, a liquid crystal layer, a lower substrate, and a lower polarizer.

[0019] Specifically, the upper polarizer is disposed on the side of the upper substrate facing away from the liquid crystal layer (i.e., the light-emitting surface of the upper substrate), and the lower polarizer is disposed on the side of the lower substrate facing away from the liquid crystal layer (i.e., the light-incident surface of the lower substrate). The transmission axes of the upper and lower polarizers are perpendicular to each other (e.g., the transmission axis of the upper polarizer is 0° and the transmission axis of the lower polarizer is 90°) or intersecting at a preset angle, used to cooperate with the optical rotation characteristics of the liquid crystal layer to achieve the display of brightness and darkness grayscale. The upper and lower polarizers can each be independently selected from iodine-based polarizing films, dye-based polarizing films, or metal wire grid polarizers.

[0020] The black matrix is ​​disposed on the surface of the upper substrate facing the liquid crystal layer, typically located between adjacent color units of the color filter and at the boundaries of pixel areas. The black matrix is ​​composed of light-shielding materials, such as black photoresist (containing black pigments such as carbon black and titanium black), chromium metal thin film, or metal oxide thin film. Its main functions are: to block stray light from the thin-film transistor area, preventing light leakage current in the channel area due to illumination, thereby reducing display contrast; to block the gaps between color filter units, preventing color mixing between pixels; and to absorb reflected ambient light, improving the contrast of the display panel under strong ambient light.

[0021] Color filters are disposed on the side of the upper substrate facing the liquid crystal layer, and are located in the same plane as the black matrix, meaning the black matrix is ​​formed in the gaps between adjacent color units of the color filter. A color filter typically includes multiple color filter units arranged in an array, specifically including at least red (R), green (G), and blue (B) filter units. White (W) or yellow (Y) filter units may also be included as needed to improve brightness or color gamut. Each color filter unit is patterned from photosensitive resin (colored photoresist) doped with corresponding pigments or dyes through photolithography processes such as coating, exposure, and development. The function of the color filter is to decompose the white light (or blue light combined with a quantum dot conversion layer) provided by the backlight module into the three primary colors of red, green, and blue, achieving full-color display by controlling the grayscale brightness of each sub-pixel.

[0022] The composite functional layer is integrated between the color filter and the liquid crystal layer, that is, it is formed directly on the surface of the color filter facing the liquid crystal layer, or indirectly formed on the color filter through a transparent planarization layer (such as acrylic resin or epoxy resin). The composite functional layer is composed of a composite material that can undergo controllable phase separation or molecular orientation change under the action of an electric field, such as polymer-dispersed liquid crystal (PDLC). Transparent electrodes (such as indium tin oxide (ITO), indium zinc oxide (IZO), or silver nanowire electrodes) are respectively disposed on both sides of the composite functional layer. By controlling the voltage applied to the transparent electrodes, the composite functional layer can reversibly switch between a transparent state and a state in which a micro-optical structure is formed: when no voltage is applied, the refractive index of the liquid crystal in the composite functional layer matches that of the polymer matrix, and the composite functional layer is in a transparent state, without limiting the angle of transmitted light; when a voltage is applied, a periodic or quasi-periodic micro-optical structure is formed inside the composite functional layer (for example, the liquid crystal molecules are arranged in a grating shape, and the polymer matrix forms a columnar or pyramidal structure). This micro-optical structure produces a deflection, convergence, or blocking effect on the incident light, thereby limiting the emitted light to a preset narrow angle range and realizing a privacy mode.

[0023] The liquid crystal layer is sealed between the upper and lower substrates and located between the composite functional layer and the lower substrate. The liquid crystal layer is composed of liquid crystal molecules with positive or negative dielectric anisotropy, such as nematic liquid crystals, smectic liquid crystals, or cholesteric liquid crystals, and is precisely maintained by a photo spacer (PS) disposed between the upper and lower substrates. The working principle of the liquid crystal layer is as follows: the thin-film transistor array (TFT array) on the lower substrate provides a driving voltage to each pixel electrode. This voltage forms an electric field with the common electrode (which can be disposed on the upper or lower substrate), driving the liquid crystal molecules to deflect, thereby modulating the polarization state of light passing through the liquid crystal layer. Combined with the polarization selection effect of the upper and lower polarizers, grayscale control from bright to dark states is achieved for each sub-pixel. This application does not particularly limit the working mode of the liquid crystal layer; any mode such as twisted nematic (TN), vertical alignment (VA), planar switching (IPS), or edge field switching (FFS) can be used.

[0024] The lower substrate and the upper substrate are disposed opposite to each other. A thin-film transistor array (TFT array) is formed on the side of the lower substrate facing the liquid crystal layer. The TFT array includes multiple scan lines (gate lines), multiple data lines (source lines), and thin-film transistors arranged in an array at the intersection of the two. Each TFT corresponds to a sub-pixel region, and each sub-pixel region also has a pixel electrode and an optional storage capacitor. The active layer of the TFT can be amorphous silicon (a-Si), low-temperature polycrystalline silicon (LTPS), oxide semiconductor (such as IGZO, IZTO), or organic semiconductor material. When a gating signal is applied to the scan line on the lower substrate, the corresponding TFT turns on, writing the grayscale voltage on the data line to the pixel electrode, thereby driving the corresponding region in the liquid crystal layer to deflect.

[0025] Based on the aforementioned layered structure, the illumination light emitted from the backlight module sequentially passes through the lower polarizer (polarization), lower substrate (transmission), liquid crystal layer (polarization modulation), composite functional layer (angle control, selectable), color filter (color separation), black matrix (light blocking and anti-color mixing), upper substrate (transmission), and upper polarizer (polarization detection) before being emitted to the viewer. The composite functional layer can selectively enable or disable the angle limiting function under voltage control, thus switching between a wide-viewing-angle sharing mode and a narrow-viewing-angle privacy mode as needed. The other layers maintain their original functions in both modes without interfering with each other.

[0026] In some embodiments, the composite functional layer comprises at least a polymer-dispersed liquid crystal (PDLC) material and a quantum dot (QD) material. For example, the PDLC material consists of a polymer matrix and liquid crystal microdroplets dispersed therein. The polymer matrix is ​​selected from photocurable or thermocurable transparent resins, including but not limited to acrylates (such as polymethyl methacrylate (PMMA), polybutyl acrylate), epoxy resins, thiol-olefins, or polyurethane polymers. The polymer matrix forms a three-dimensional network or porous framework structure in the composite functional layer. The liquid crystal microdroplets are selected from nematic liquid crystals with positive or negative dielectric anisotropy. The liquid crystals are dispersed in the polymer matrix in the form of micron-sized droplets. The ordinary refractive index of the liquid crystal microdroplets is... unusual optical refractive index Refractive index of polymer matrix The following relationship must be satisfied: when no voltage is applied, and When a voltage is applied to orient the liquid crystal molecules along the direction of the electric field, the effective refractive index approaches 1 / 2. .

[0027] The quantum dot material is selected from semiconductor nanocrystals, including but not limited to: cadmium-containing quantum dots: CdSe, CdS, CdTe, CdSe / ZnS (core-shell structure); cadmium-free quantum dots: InP, InP / ZnS, CuInS2, CuInS2 / ZnS, AgInS2; perovskite quantum dots: CsPbBr3, CsPbI3, CsPbCl3 and their mixed halogen systems; carbon quantum dots or graphene quantum dots. In this embodiment, the excitation spectrum of the quantum dots in the quantum dot material is precisely matched with the blue and blue-green light bands with the highest energy efficiency in the white backlight source, while its emission spectrum is highly consistent with the transmission band of the color filter in the display module. Thus, by utilizing the photoluminescence effect of quantum dots, the non-ideal wavelength components in the backlight that would originally cause spectral pollution are converted into high-purity red and green light, thereby achieving compensation and improvement of the display color gamut.

[0028] In this embodiment, the composite functional layer is formed by uniformly doping quantum dot material into a polymer-dispersed liquid crystal material. For example, the composite functional layer is a three-phase composite system composed of a polymer matrix, liquid crystal microdroplets dispersed in the polymer matrix, and quantum dot material uniformly dispersed throughout the composite functional layer. "Uniform doping" refers to the statistically uniform distribution of quantum dot material on a macroscopic scale (i.e., throughout the entire volume of the composite functional layer), without local aggregation or significant concentration gradients of quantum dots. Specifically, the quantum dot material exists simultaneously in both the polymer matrix and the liquid crystal microdroplets, with essentially equal concentrations in both phases, or uniformly distributed in both phases according to a predetermined ratio. This whole-phase uniform doping simplifies the fabrication process to the greatest extent and utilizes the direct interaction between quantum dots and liquid crystal molecules to obtain additional electro-optical modulation effects.

[0029] In some embodiments, the micro-optical structure is a microprism array used to focus incident light within a preset viewing angle. For example, in the composite functional layer of the present invention, the microprism array is not pre-fabricated and then bonded to the display panel, but is formed in situ by voltage-controlled orientation of liquid crystal droplets in polymer-dispersed liquid crystal material and deformation of the polymer matrix. Specifically, in the transparent state without applied voltage, the liquid crystal droplets in the composite functional layer are randomly oriented, the polymer matrix maintains a flat film morphology, and there is no microprism structure. When an AC voltage higher than the threshold voltage is applied, the following evolution process occurs inside the composite functional layer: First, the liquid crystal molecules in the liquid crystal droplets are ordered along the electric field direction (i.e., the direction perpendicular to the substrate plane), causing a change in the effective refractive index of the liquid crystal droplets; second, due to the dielectric anisotropy force and electrostriction effect generated by the orientation of the liquid crystal molecules, the polymer matrix deforms at the microscale, and the originally flat film surface or internal interface forms a microstructure with periodic undulations; finally, this micro-deformation is maintained in the cured polymer network, forming a stable microprism array.

[0030] It should be noted that the microprism array can also be formed by another mechanism: during the preparation of the composite functional layer, by applying a specific electric field (e.g., generating a non-uniform electric field through patterned electrodes) to the upper and lower transparent electrodes, the liquid crystal microdroplets in different regions are oriented differently, thereby inducing a grating structure with a periodic distribution of refractive index in the polymer matrix. The deflection effect of this refractive index grating on light is equivalent to that of the microprism array.

[0031] In some embodiments, the display module further includes transparent electrodes disposed on both sides of the composite functional layer. For example, "disposed on both sides of the composite functional layer" means that a transparent conductive film is disposed on the side of the composite functional layer facing the liquid crystal layer and the side facing the color filter, respectively. These two transparent electrodes together constitute a driving electrode pair, which is used to apply voltage to the composite functional layer to control the orientation of the liquid crystal droplets and the deformation of the polymer matrix therein, thereby realizing the reversible switching of the composite functional layer between the transparent state and the micro-optical structure state.

[0032] Specifically, in the stacked structure of the display module, from the light-emitting side to the backlight side, the layers are as follows: upper polarizer, upper substrate, color filter, first transparent electrode, composite functional layer, second transparent electrode, liquid crystal layer, lower substrate, and lower polarizer. The first transparent electrode is disposed between the color filter and the composite functional layer, i.e., above the composite functional layer or facing the light-emitting side; the second transparent electrode is disposed between the composite functional layer and the liquid crystal layer, i.e., below the composite functional layer or facing the backlight side. When an AC voltage is applied between the first and second transparent electrodes, the composite functional layer experiences an electric field perpendicular to the substrate direction, driving the liquid crystal molecules within the liquid crystal droplets to align along the electric field direction and inducing deformation of the polymer matrix to form a microprism array. In this embodiment, the transparent electrode is a full-surface covered ITO transparent electrode. For example, from the stacking order, the position of the full-surface covered ITO transparent electrode in the display module is as follows: the upper polarizer is at the top, the upper substrate is below the upper polarizer, and the color filter is below the upper substrate. After the color filter is fabricated, a continuous ITO thin film is deposited on its entire surface using magnetron sputtering to form the first transparent electrode. Subsequently, a composite functional layer is prepared on the entire surface of the first transparent electrode. After the composite functional layer is cured, another continuous ITO thin film is deposited on its entire surface to form the second transparent electrode. Below the second transparent electrode is the liquid crystal layer, followed by the lower substrate and the lower polarizer. In this way, the composite functional layer is completely sandwiched between the upper and lower layers of ITO transparent electrodes that cover the entire surface, forming a uniform electric field region in the entire display area.

[0033] In some embodiments, the display module further includes a driving chip, which applies or removes a voltage to the transparent electrodes to achieve switching between a transparent state and a state in which a micro-optical structure is formed. For example, the driving chip is an integrated circuit device used to control the driving voltage waveform for switching the state of the composite functional layer, and applies the voltage to the transparent electrodes on both sides of the composite functional layer through lead lines in the display module, or removes the voltage from the transparent electrodes, thereby achieving reversible switching of the composite functional layer between a transparent state and a state in which a micro-optical structure is formed.

[0034] The driver chip can be a dedicated chip with independent configuration for driving control of composite functional layers; or it can be integrated into the same chip with a timing controller or power management integrated circuit to reduce the number of components and manufacturing cost of the display module. Regardless of the integration method, the driver chip, as the core unit for voltage supply and control, has its output terminal electrically connected to the first transparent electrode and the second transparent electrode respectively through conductive leads on the display module.

[0035] refer to Figure 1 The microcontroller unit in the display module receives commands to enable or disable the privacy function and sends control signals to the driver chip via a general purpose input / output port. The driver chip generates corresponding drive voltage waveforms based on the control signals and applies them to the upper and lower ITO electrodes through its positive and negative output terminals, respectively. An electric field is formed between the upper and lower ITO electrodes, and the composite functional layer switches between a transparent state and a state forming a micro-optical structure under the influence of this electric field. Specifically, a GPIO pin of the microcontroller unit is connected to a pin of the driver module. The Vout+ output terminal of the driver module is connected to the upper ITO electrode of the composite functional layer via a wire, and the Vout- output terminal of the driver module is connected to the lower ITO electrode of the composite functional layer via a wire. When transparency of the composite functional layer is required, the GPIO port of the microcontroller unit sends a low-level signal, the driver module stops outputting, the voltage across the composite functional layer becomes 0, and the state of the composite functional layer becomes transparent. When the composite functional layer needs to be atomized (opaque), the GPIO port of the microcontroller sends a high-level signal, which drives the internal circuit of the module to start working, generating high-voltage AC power, which is output to the ITO electrode of the composite functional layer, and the state of the composite functional layer changes to the state of the micro-optical structure.

[0036] The display module of this application integrates a composite functional layer between the color filter and the liquid crystal layer inside the display panel, eliminating the need for an additional privacy screen protector layer and avoiding an increase in the thickness of the display module. Simultaneously, this composite functional layer exhibits high light transmittance in its transparent state. In the privacy screen protector state, which forms a micro-optical structure, privacy is achieved through light angle limitation rather than absorption, thus not significantly reducing light transmittance and avoiding loss of display brightness and increased backlight power consumption.

[0037] This application provides a display device, which includes at least the aforementioned display module. For example, a display device refers to a complete electronic device capable of receiving electrical signals and converting them into visual images. It includes not only a display module for display, but also a drive circuit for driving the display module, a power management unit for supplying power, an interface unit for receiving user input or external signals, and structural components for housing and protecting the aforementioned components.

[0038] The display device of this application integrates the aforementioned display module, which has an electrically controllable switchable composite functional layer that can switch between a wide-viewing-angle sharing mode and a narrow-viewing-angle privacy mode as needed, thereby taking into account both privacy protection and shared viewing needs. The other components of the display device are designed and configured around this core display module to jointly provide users with a complete display experience.

[0039] It should be noted that the display devices in this application cover a variety of product forms, including but not limited to portable electronic devices, computer peripherals, home appliance display panels, commercial display terminals, automotive display devices, medical display devices, and aerospace display devices.

[0040] Figure 2 A flowchart illustrating a control method for a display device according to an embodiment of this application is provided.

[0041] like Figure 2 As shown, the control method includes steps S210 and S230.

[0042] In step S210, the voltage across the composite functional layer is detected; In step S220, when there is no voltage on either side of the composite functional layer, the state of the composite functional layer is controlled to be transparent. In step S230, when there is a voltage on both sides of the composite functional layer, the state of the composite functional layer is controlled to be a micro-optical structure.

[0043] For example, the control method can be initiated under various triggering conditions, including but not limited to: when the display device is powered on, when the display device is woken up from standby or hibernation, when the user manually triggers the privacy mode switch, or when the application requests to switch the display mode through the system interface.

[0044] For example, in the scenario of powering on the display device, the control method starts along with the initialization of the entire display system. After the power management unit establishes a stable system voltage, the microcontroller unit begins to execute its firmware program, which includes the initialization part of this control method. During the initialization phase, the microcontroller unit sets the general-purpose input / output pins of the composite function layer driver module to the default state, such as no voltage being applied, i.e., the voltage on both sides of the composite function layer is zero. This ensures that the composite function layer is transparent during the power-on process and before the user makes a specific selection, allowing the user to view the power-on screen and system interface normally.

[0045] In scenarios where the user manually triggers the switching of the privacy mode, the control method is triggered as an interrupt service routine or system service call. At this time, the control method does not need to execute the entire initialization process from the beginning; it can directly enter the user selection judgment step and quickly change the state of the composite functional layer according to the user's switching command. For example, it can detect the voltage on both sides of the composite functional layer. When there is no voltage on both sides of the composite functional layer, it controls the state of the composite functional layer to be transparent; when there is voltage on both sides of the composite functional layer, it controls the state of the composite functional layer to be in a micro-optical structure state.

[0046] In some embodiments, controlling the state of the composite functional layer to be transparent includes controlling the light refractive index of the liquid crystal molecules in the composite functional layer to match the light refractive index of the polymer network, so that the state of the composite functional layer is transparent; controlling the state of the composite functional layer to be a micro-optical structure includes controlling the light refractive index of the liquid crystal molecules in the composite functional layer to be greater than the light refractive index of the polymer network, so that the composite functional layer is a micro-optical structure.

[0047] refer to Figure 3 There is no voltage on either side of the composite functional layer, i.e., "PDLC-QD layer (composite functional layer) voltage off" in the diagram. At this time, the control method detects no voltage on either side of the composite functional layer, and the layer is in a transparent state. Looking at the stacked structure, the light emitted from the backlight module (light source) passes sequentially through the lower polarizer, the TFT glass substrate, the liquid crystal layer (for grayscale modulation), the PDLC-QD layer (voltage off), the color filter (for color separation), and the upper polarizer before exiting. The light diffuses to both sides at a wide angle in the diagram, indicating that the display module is operating in a wide viewing angle sharing mode, allowing users to freely view the screen content from different angles. Simultaneously, the quantum dot materials in the PDLC-QD layer are still effectively excited by the blue and blue-green light from the backlight even in the voltage-off state, emitting high-purity red and green light through photoluminescence, compensating for and enhancing the display color gamut, thus achieving both wide viewing angle and high color gamut.

[0048] For example, when there is no voltage across the composite functional layer, the polymer-dispersed liquid crystal material inside the composite functional layer is in its thermodynamic equilibrium state, i.e., its natural state. In this state, the composite functional layer exhibits the optical properties of transparency. The composite functional layer consists of a polymer matrix and liquid crystal microdroplets dispersed within it. The polymer matrix is ​​a three-dimensional cross-linked network formed by ultraviolet light curing, and its molecular structure is relatively stable after curing, and will not deform or rearrange under voltage-free conditions. The liquid crystal molecules within the liquid crystal microdroplets are the most electric field-sensitive components in the composite functional layer. In the absence of an external electric field, the liquid crystal molecules within the liquid crystal microdroplets are not subject to the directional force of the electric field, and their orientation is determined by two factors: first, the mutual elastic interaction between liquid crystal molecules tends to keep adjacent molecules aligned in parallel; second, the anchoring effect of the polymer matrix interface on the liquid crystal molecules tends to orient the liquid crystal molecules at the interface along a specific direction.

[0049] Specifically, in the voltage-free state, the effective refractive index of the liquid crystal droplets is essentially matched with the refractive index of the polymer matrix. For example, the refractive index of the polymer matrix is ​​configured to be equal to or very close to the ordinary light refractive index of the liquid crystal droplets. In the voltage-free state, due to the disordered orientation of the liquid crystal molecules within the liquid crystal droplets, their average effective refractive index is close to the average of the ordinary light refractive index and the extraordinary light refractive index. Although this average value is not equal to the ordinary light refractive index, the difference between it and the refractive index of the polymer matrix is ​​controlled within a very small range. Under these conditions, the composite functional layer is in a transparent state.

[0050] refer to Figure 4 A voltage exists on both sides of the composite functional layer, as shown in the diagram as "PDLC-QD layer voltage on". At this time, the control method applies a driving voltage to the ITO electrodes on both sides of the composite functional layer through the microcontroller unit and the drive module. Under the influence of the electric field, the composite functional layer forms a microprism array, entering a micro-optical structure state. As can be clearly seen from the light propagation diagram, the angular distribution of the emitted light is significantly narrowed. The light mainly converges within a small angle range directly in front of the screen, while light in large angle directions is significantly suppressed. This achieves a narrow viewing angle privacy display, preventing onlookers from the side from effectively viewing the screen content. Simultaneously, the quantum dot material in the PDLC-QD layer continues to be excited by the blue and blue-green light from the backlight even in the voltage-on state, maintaining high color gamut color performance while providing privacy protection, achieving a balance between privacy protection and excellent image quality.

[0051] For example, when there is a voltage of sufficient amplitude on both sides of the composite functional layer, the polymer-dispersed liquid crystal material inside the composite functional layer undergoes a series of physical changes under the action of the electric field, changing from a transparent state to a micro-optical structure state. This transformation process involves the orientation change of liquid crystal molecules in the liquid crystal microdroplets and the microscopic deformation of the polymer matrix.

[0052] Specifically, the liquid crystal molecules within the liquid crystal droplets undergo orientation changes under the influence of an electric field. In the absence of voltage, the liquid crystal molecules within the droplets exhibit disordered multi-domain orientation, with the molecular orientation vectors of each region randomly distributed. When a sufficiently strong electric field is applied to both sides of the composite functional layer, due to the dielectric anisotropy of the liquid crystal molecules, their long axes tend to align along the direction of the electric field to minimize the system's free energy. For nematic liquid crystals with positive dielectric anisotropy, the long axes of the liquid crystal molecules will turn parallel to the direction of the electric field; for nematic liquid crystals with negative dielectric anisotropy, the long axes of the liquid crystal molecules will turn perpendicular to the direction of the electric field.

[0053] Under a sufficiently strong electric field, the polymer matrix undergoes microscopic deformation, forming a microprism array. For example, when liquid crystal molecules within a liquid crystal droplet align along the direction of the electric field, dielectric anisotropic forces are generated at the interface between the liquid crystal molecules and the polymer matrix. Simultaneously, the orientation of the liquid crystal molecules alters the effective dielectric constant of the liquid crystal droplet, resulting in microscopic non-uniformity in the electric field distribution within the composite functional layer. Under the influence of this electric field, the polymer matrix undergoes electrostrictive deformation, and periodic undulations begin to appear on the originally flat film surface or internal interface. These undulations exhibit a prism-like geometric structure at the microscale, i.e., a microprism array. At this point, the refractive index of the liquid crystal molecules within the composite functional layer is greater than the refractive index of the polymer network, and the composite functional layer exhibits a micro-optical structure.

[0054] In this embodiment, the morphological characteristics of the microprism array can be controlled by adjusting the amplitude of the applied voltage. When the applied voltage is slightly higher than the threshold voltage, the deformation of the polymer matrix is ​​small, resulting in a lower height and blunter apex angles of the formed microprism array, leading to a weaker ability to deflect light. As the applied voltage increases, the electrostriction force strengthens, the degree of deformation of the polymer matrix increases, the height of the microprism array increases, the apex angles become sharper, and the ability to deflect light is enhanced. When the applied voltage reaches the saturation voltage, the deformation of the microprism array reaches its maximum value, resulting in the strongest viewing angle restriction effect. This voltage-deformation relationship enables the composite functional layer of this invention to achieve continuously adjustable privacy protection strength.

[0055] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A display module, comprising: The display panel, from top to bottom, includes at least a color filter, a composite functional layer, and a liquid crystal layer; A backlight module, located below the display panel, is used to provide an illumination source; The composite functional layer is integrated between the color filter and the liquid crystal layer, and can switch between a transparent state and a state forming a micro-optical structure by controlling the voltage applied to it.

2. The display module according to claim 1, characterized in that, The composite functional layer comprises at least a polymer-dispersed liquid crystal material and a quantum dot material.

3. The display module according to claim 2, characterized in that, The composite functional layer is formed by uniformly doping quantum dot materials into a polymer-dispersed liquid crystal material.

4. The display module according to claim 1, characterized in that, The micro-optical structure is a micro-prism array, used to focus incident light within a preset viewing angle.

5. The display module according to claim 1, characterized in that, It also includes transparent electrodes, which are disposed on both sides of the composite functional layer.

6. The display module according to claim 5, characterized in that, It also includes a driving chip, which applies or removes voltage to the transparent electrode to switch between the transparent state and the state of forming the micro-optical structure.

7. The display module according to claim 5, characterized in that, The transparent electrode is an ITO transparent electrode that covers the entire surface.

8. A display device, the display device comprising at least the display module according to any one of claims 1 to 7.

9. A control method applied to the display device of claim 8, comprising: Detect the voltage across the composite functional layer; When there is no voltage on either side of the composite functional layer, the state of the composite functional layer is controlled to be transparent; When a voltage is present on both sides of the composite functional layer, the state of the composite functional layer is controlled to be a micro-optical structure.

10. The display device according to claim 9, characterized in that, Controlling the state of the composite functional layer to be transparent includes controlling the optical refractive index of the liquid crystal molecules in the composite functional layer to match the optical refractive index of the polymer network, so that the state of the composite functional layer is transparent. Controlling the state of the composite functional layer to be a micro-optical structure includes controlling the optical refractive index of the liquid crystal molecules in the composite functional layer to be greater than the optical refractive index of the polymer network, so that the composite functional layer is in a micro-optical structure state.

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