Mirror display device

Abstract

The present invention belongs to the field of display technology and relates to a mirror display device. The device includes a first polarizer, a reflective layer that reflects light of a certain polarization direction, such as a metal wire grid polarizer or a brightness enhancement film in an APCF polarizer, a first substrate, a liquid crystal layer, a second substrate, and a second polarizer, which are arranged in sequence. By using a reflective layer that reflects light of a certain polarization direction, such as a metal wire grid polarizer or a brightness enhancement film in an APCF polarizer, instead of a semi-transmissive, semi-reflective film, the reflectivity can be doubled. A currently commonly used ordinary liquid crystal display is specially combined with the reflective layer of the present invention to form a mirror display device with a simple structure, compatibility with traditional manufacturing processes, and low cost.

Description

Technical Field

[0001] The invention belongs to the field of display technology and relates to a mirror display device. Background Art

[0002] Based on the source of light used to display the image, display devices can be divided into transmissive display devices, reflective display devices, and mirror display devices. Specifically, transmissive display devices use a backlight module as their light source, which reduces the contrast of the displayed image outdoors or under strong sunlight. Reflective display devices use an external light source as their light source, which provides better display effects outdoors and under strong sunlight, but it is difficult to obtain a display image with high resolution, high contrast, and high color quality. Mirror display devices use a backlight module and an external light source as their light source, which effectively solves the problems of transmissive and reflective display devices.

[0003] Mirror display is a new display technology that has emerged in recent years. It can both display images and reflect them, acting as a mirror. Its main applications include displaying news highlights, weather forecasts, calendars, emails, social networks, reminders, and other information. Users can look in the mirror and get daily updates, truly improving their quality of life through intelligent technology. The mirror display panel is constructed by attaching a semi-transmissive, semi-reflective film to an existing liquid crystal display panel. This film allows users to see the day's weather conditions or real-time news through the mirror while using the mirror. Mirror display devices are primarily implemented by attaching a semi-transmissive, semi-reflective polyethylene terephthalate (PET) film to the light-emitting side of the liquid crystal display panel or by sputtering a semi-transmissive, semi-reflective metal film.

[0004] For this semi-transmissive and semi-reflective film structure, due to the influence of the semi-transmissive and semi-reflective film, the transmittance of the liquid crystal display panel will be halved after passing through the semi-transmissive and semi-reflective film, and the reflectivity of the ambient light will also be halved. At the same time, glare will occur when the ambient light is strong.

[0005] Placing a phase-retarding liquid crystal cell and auxiliary polarizer on top of a transflective mirror display structure allows for adjustable transmittance and reflectance, providing partial mirror and display functionality. However, this approach suffers from complex and bulky design, requiring two liquid crystal cells. Furthermore, due to the effects of the transflective film, the transmittance of the LCD panel is halved after passing through the film, and the reflectance of ambient light is also halved. Furthermore, the phase-retarding liquid crystal cell further reduces the transmittance and reflectance.

[0006] Another mirror display substrate has a repeating arrangement of reflective and transmissive areas. The mirror display substrate comprises a first control unit, a reflective layer, and a second control unit transmissive area on the first substrate, forming a reflective and transmissive area. The reflective area is provided with a reflective layer. The first and second control units control the reflective and transmissive areas, respectively, so that image display and mirror display are no longer performed simultaneously, thus avoiding the influence of reflected light on the image during mirror display. However, this method has the disadvantages of a complex manufacturing process, half of the pixels are reflective and half are projected, and resolution is reduced. Summary of the Invention

[0007] The present invention addresses the problems of traditional mirror display devices, such as complex structure, bulkiness, complicated process and high production cost; and the problem that in the prior art, due to the influence of the semi-transparent and semi-reflective film, the reflectivity is reduced by half, and considering the influence of 1 / 4 wave plates or other additional devices, the mirror reflectivity of the device is further reduced compared with the prior art. A new mirror display device is proposed.

[0008] In order to achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0009] The device includes a first polarizer, a reflective layer that reflects light in a certain polarization direction (such as a metal wire grid polarizer, a brightness enhancement film in an APCF polarizer), a first substrate (containing a TFT array), a liquid crystal layer, a second substrate (containing a color filter), and a second polarizer, which are arranged in sequence. Figure 1 shown.

[0010] The working principle of the mirror function is as follows: Ambient natural light enters the device through the polarizer, forming polarized light. The polarized light passes through the reflective layer and is reflected by the reflective layer and returns to the polarizer, realizing the mirror function.

[0011] The working principle of the display function: relying on liquid crystal molecules to achieve brightness and darkness changes under the drive of electric field.

[0012] Preferably, the liquid crystal device of this technology can adopt IPS mode, FFS mode, VA mode and TN mode.

[0013] Working principle of metal wire grid polarizer: Metal wire grid (Nano wire-grid polarizer) polarizer can selectively transmit TM polarized light component (polarization direction perpendicular to the wire grid direction, i.e. p light) and reflect TE polarized light component (polarization direction parallel to the wire grid direction, i.e. s light). Figure 2 shown.

[0014] Preferably, the working principle of the brightness enhancement film in the APCF polarizing plate is to be prepared by using a multilayer film, which can achieve the same function as the metal wire grid polarizer.

[0015] Preferably, the reflective layer can be attached to the first polarizer by forming a composite film. For the metal wire grid polarizer technology, the reflective layer can also be made directly on the outer surface of the first substrate or on the inner surface of the first substrate, that is, between the substrate and the TFT array.

[0016] Technical requirements:

[0017] The polarization direction of the light reflected by the reflective layer is the same as the direction of the light transmission axis of the first polarizer, that is, the polarization direction of the light transmitted by the reflective layer is perpendicular to the direction of the light transmission axis of the first polarizer.

[0018] In IPS, FFS or VA display mode, the thickness of the liquid crystal layer is required to be 1 / 2 wavelength, which is equivalent to a half-wave plate. The wavelength is selected within the visible light range, and generally the wavelength of green light waves, to which the human eye is more sensitive, is preferred.

[0019] The manufacturing process for the liquid crystal display device of the present invention is compatible with the manufacturing process for LCDs. The substrate can be a transparent glass substrate or a transparent plastic substrate. Generally, a relatively thin substrate is selected without affecting device performance. For example, the thickness of the glass can be between 0.1 and 0.4 mm. The TFT (thin film transistor) array and color filter on the substrate are manufactured in the same manner as in LCDs and will not be described in detail here. The two layers of glass are sealed with a liquid crystal layer in between. The thickness of the liquid crystal layer is generally 2 to 5 μm. The surface of the substrate in contact with the liquid crystal is coated with an organic alignment layer (generally a polyimide material). Tribo or photo-alignment techniques are generally used to align the liquid crystal molecules in the desired direction. The wire grid polarizer is formed using nanoimprint lithography and physical vapor deposition, or by conventional etching methods. The metal layer can be plated with silver, aluminum, chromium, TiO2, or nano-metal chromium aluminum, and has a thickness generally between 100 and 300 nm. The polarizer material is generally any polarizer commonly used in LCDs, and has a thickness generally between 100 and 200 μm. The working principle of the brightness enhancement film in the APCF polarizing plate is to use a multi-layer film with a thickness of tens of microns.

[0020] Compared with the prior art, the advantages and positive effects of the present invention are:

[0021] 1. Using a reflective layer that reflects light in a certain polarization direction (such as a metal wire grid polarizer or a brightness enhancement film in an APCF polarizer) instead of a semi-transmissive and semi-reflective film can double the reflectivity.

[0022] 2. The currently commonly used ordinary liquid crystal display is specially matched with the reflective layer in this invention to form a mirror display device, which has a simple structure, is compatible with traditional preparation processes, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the mirror display device structure.

[0024] Figure 2 This is a diagram of the working principle of a metal wire grid polarizer.

[0025] Figure 3 Schematic diagram of the mirror display structure in IPS or FFS mode.

[0026] Figure 4 Schematic diagram of the cross-section of the IPS or FFS mode mirror display device structure.

[0027] Figure 5 Schematic diagram of the mirror display structure in IPS or FFS mode.

[0028] Figure 6 Schematic diagram of the mirror display structure in IPS or FFS mode.

[0029] Figure 7 Schematic diagram of the mirror display structure in IPS or FFS mode.

[0030] Figure 8 Schematic diagram of the VA mode mirror display structure.

[0031] Figure 9 Schematic diagram of the VA mode mirror display structure.

[0032] Figure 10 Schematic diagram of the TN mode mirror display structure.

[0033] Figure 11 Schematic diagram of the TN mode mirror display structure. DETAILED DESCRIPTION

[0034] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] The embodiment is introduced by taking a metal wire grid polarizer as an example. The brightness enhancement film in the APCF polarizer serves as a reflective layer and has a similar principle to that of a metal wire grid polarizer.

[0037] Example 1, as Figure 3As shown. The long axis of the liquid crystal molecules is along the y-axis, the transmission axes of the first and second polarizers are along the x-axis, and the polarization direction of the light reflected by the reflective layer is the same as the transmission axis of the second polarizer, that is, the polarization direction of the light transmitted by the reflective layer is perpendicular to the transmission axis of the first polarizer. Working principle: When no electric field is applied, the ambient natural light incident on the device forms linearly polarized light after passing through the second polarizer. In this state, the polarization direction does not change, and it is directly emitted after being reflected by the reflective layer, realizing the mirror function, such as Figure 4 shown.

[0038] The state when no electric field is applied is also the brightest state of the display function. When an electric field is applied to drive the liquid crystal molecules, when the average optical axis (director) of the liquid crystal is at a 45-degree angle to the y-axis, the liquid crystal at this time is equivalent to a 1 / 2 wave plate. The ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees, that is, along the y-axis. At this time, the polarization direction is consistent with the polarization direction of the transmitted light of the reflective layer, and it is completely absorbed by the first polarizer through the reflective layer, presenting a dark state.

[0039] When the average optical axis (director) of the liquid crystal is at an angle of θ (between 0 and 45 degrees) to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the reflective layer, and the component of the linear polarized light in the x-axis direction is transmitted through the reflective layer. When it passes through the liquid crystal layer, it is equivalent to passing through another 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction of the component in the x-axis direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the second polarizer, and the component of the linear polarized light in the x-axis direction is transmitted through the second polarizer and emitted from the display device, forming a gray state.

[0040] By controlling the voltage, the change from bright state to gray state to dark state can be realized. The emitted light intensity is related to cos 4 (2*θ) is proportional to the time domain, realizing the display function, showing news highlights, weather forecast, calendar, email, social network, reminders and other information.

[0041] Example 2: The direction of the transmission axis of the second polarizer in Example 1 is changed to be along the y-axis direction, such as Figure 4 As shown, the long axis of the liquid crystal molecules is along the y-axis, the transmission axis of the first polarizer is along the x-axis, and the polarization direction of the light reflected by the reflective layer is perpendicular to the transmission axis of the second polarizer.

[0042] Working principle:

[0043] When no electric field is applied, the ambient natural light incident on the device forms linearly polarized light after passing through the second polarizer. In this state, the polarization direction does not change. This direction is the same as the polarization direction of the transmitted light of the reflective layer. After passing through the reflective layer, it is absorbed by the first polarizer to achieve a dark state.

[0044] An electric field is applied to drive the liquid crystal molecules. When the average optical axis (director) of the liquid crystal is at a 45-degree angle to the y-axis, the liquid crystal is equivalent to a 1 / 2 wave plate. The ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees, that is, along the x-axis. At this time, the polarization direction is consistent with the polarization direction of the reflected light of the reflective layer and is completely reflected. The linearly polarized light passes through the liquid crystal layer again, which is equivalent to passing through a 1 / 2 wave plate again. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees. The polarization direction of the linear polarized light reaching the second polarizer is consistent with the transmission axis direction of the second polarizer and is completely emitted. This state is the mirror mode.

[0045] When the average optical axis (director) of the liquid crystal is at an angle of θ (between 0 and 45 degrees) to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated by 2θ, that is, the angle with the y-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the reflective layer, and the component of the linear polarized light in the x-axis direction is transmitted through the reflective layer. After passing through the liquid crystal layer, it is equivalent to passing through another 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction of the component in the x-axis direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the x-axis direction is absorbed by the second polarizer, and the component of the linear polarized light in the y-axis direction is transmitted through the second polarizer and emitted from the display device, forming a gray state.

[0046] By controlling the voltage, the light state can be changed from bright state to gray state to dark state. 4 (2*θ) is proportional to the time domain, realizing the display function, showing news highlights, weather forecast, calendar, email, social network, reminders and other information.

[0047] Example 3: The direction of the liquid crystal arrangement in Example 1 is changed to be at a 45-degree angle to the y-axis, as shown in FIG. Figure 6 shown.

[0048] Working principle:

[0049] When no electric field is applied,

[0050] When no electric field is applied, when the optical axis (director) of the liquid crystal molecules is at a 45-degree angle to the y-axis, the liquid crystal is equivalent to a 1 / 2 wave plate. The ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees, that is, along the y-axis. At this time, the polarization direction is consistent with the polarization direction of the transmitted light of the reflective layer, and it is completely absorbed by the first polarizer through the reflective layer, presenting a dark state.

[0051] When an electric field is applied, when the average optical axis (director) of the liquid crystal is parallel to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the second polarizer. In this state, the polarization direction does not change, and it is directly emitted after being reflected by the reflective layer, realizing the mirror function. This state is also the brightest state of the display function.

[0052] When the average optical axis (director) of the liquid crystal is at an angle of θ (between 0 and 45 degrees) to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the reflective layer, and the component of the linear polarized light in the x-axis direction is transmitted through the reflective layer. When it passes through the liquid crystal layer, it is equivalent to passing through another 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction of the component in the x-axis direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the second polarizer, and the component of the linear polarized light in the x-axis direction is transmitted through the second polarizer and emitted from the display device, forming a gray state.

[0053] By controlling the voltage, the change from bright state to gray state to dark state can be realized. The emitted light intensity is related to cos 4 (2*θ) is proportional to the time domain, realizing the display function, showing news highlights, weather forecast, calendar, email, social network, reminders and other information.

[0054] Example 4: The direction of the liquid crystal arrangement in Example 2 is changed to a direction at a 45-degree angle to the y-axis, such as Figure 7 shown.

[0055] Working principle:

[0056] No electric field is applied to drive the liquid crystal molecules. When the optical axis (director) of the liquid crystal is at a 45-degree angle to the y-axis, the liquid crystal is equivalent to a 1 / 2 wave plate. The ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees, that is, along the x-axis. At this time, the polarization direction is consistent with the polarization direction of the reflected light of the reflective layer and is completely reflected. The linearly polarized light passes through the liquid crystal layer again, which is equivalent to passing through a 1 / 2 wave plate again. It is still linearly polarized light, but the linear polarization direction is rotated 90 degrees. The polarization direction of the linear polarized light reaching the second polarizer is consistent with the transmission axis direction of the second polarizer and is completely emitted. This state is the mirror mode.

[0057] When an electric field is applied, when the optical axis (director) of the liquid crystal is parallel to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the second polarizer. In this state, the polarization direction does not change. This direction is the same as the polarization direction of the transmitted light of the reflective layer. After passing through the reflective layer, it is absorbed by the first polarizer, realizing the dark state.

[0058] When the average optical axis (director) of the liquid crystal is at an angle of θ (between 0 and 45 degrees) to the y-axis, the ambient natural light incident on the device forms linearly polarized light after passing through the first polarizer. When it reaches the reflective layer (metal wire grid polarizer), it is equivalent to passing through a 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction is rotated by 2θ, that is, the angle with the y-axis is 2θ. The component of the linear polarized light in the y-axis direction is absorbed by the reflective layer, and the component of the linear polarized light in the x-axis direction is transmitted through the reflective layer. After passing through the liquid crystal layer, it is equivalent to passing through another 1 / 2 wave plate. It is still linearly polarized light, but the linear polarization direction of the component in the x-axis direction is rotated by 2θ, that is, the angle with the x-axis is 2θ. The component of the linear polarized light in the x-axis direction is absorbed by the second polarizer, and the component of the linear polarized light in the y-axis direction is transmitted through the second polarizer and emitted from the display device, forming a gray state.

[0059] By controlling the voltage, the light state can be changed from bright state to gray state to dark state. 4 (2*θ) is proportional to the time domain, realizing the display function, showing news highlights, weather forecast, calendar, email, social network, reminders and other information.

[0060] Example 5: In this example, the liquid crystal operates in VA mode.

[0061] The long axis direction of the liquid crystal molecules in Example 1 is aligned with the z-axis. An electric field is applied to tilt the liquid crystal molecules from an upright state to a flat state. The projection of the average optical axis of the liquid crystal molecules in the xy plane forms an angle of 45 degrees with the y-axis. Figure 8 shown.

[0062] Example 6:

[0063] The long axis direction of the liquid crystal molecules in Example 2 is aligned with the z-axis. An electric field is applied to tilt the liquid crystal molecules from an upright state to a flat state. The projection of the average optical axis of the liquid crystal molecules in the xy plane forms an angle of 45 degrees with the y-axis. Figure 9 shown.

[0064] Example 7: In this example, the liquid crystal operates in TN mode.

[0065] The long axis direction of the liquid crystal molecules in Example 1 is aligned with the z-axis. An electric field is applied to tilt the liquid crystal molecules from an upright state to a flat state. The projection of the average optical axis of the liquid crystal molecules in the xy plane forms an angle of 45 degrees with the y-axis. Figure 10 shown.

[0066] Example 8: The long axis direction of the liquid crystal molecules in Example 2 is aligned with the z-axis. An electric field is applied to tilt the liquid crystal molecules from an upright state to a flat state. The projection of the average optical axis of the liquid crystal molecules in the xy plane forms an angle of 45 degrees with the y-axis, as shown in FIG. Figure 11 shown.

[0067] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A mirror display device, characterized in that : comprising a first polarizer, a reflective layer, a first substrate, a liquid crystal layer, a second substrate and a second polarizer in sequence, wherein the polarization direction of light reflected by the reflective layer is the same as the direction of the transmission axis of the first polarizer, and the thickness of the liquid crystal layer is 1 / 2 wavelength; The reflective layer is a metal wire grid polarizer or a brightness enhancement film in an APCF polarizer; The first substrate contains a TFT array, and the second substrate contains a color filter.

2. The mirror display device according to claim 1, characterized in that : The device operates in IPS mode, FFS mode, VA mode or TN mode.

3. The mirror display device according to claim 1, characterized in that : The reflective layer and the first polarizer form a composite film for attachment, or the reflective layer is the outer surface of the first substrate.

4. The mirror display device according to claim 1, characterized in that :The thickness of the liquid crystal layer is 1 / 2 the wavelength of the green light wave.

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