In-plane switching liquid crystal display

Abstract

The present application provides an in-plane switching liquid crystal display. It includes a MiniLED backlight, a first polarizer, a liquid crystal unit, and a second polarizer. The liquid crystal unit is located between the first and second polarizers, and the absorption axes of the first and second polarizers are perpendicular to each other. The optical axis of the liquid crystal unit is parallel to the absorption axis of the first polarizer. The first protective film on the second polarizer includes a negative biaxial retardation film and a positive C plate. The negative biaxial retardation film has an in-plane retardation value of 50 to 250 nm at a wavelength of 550 nm and a thickness-direction retardation value of 60 nm to 260 nm. The positive C plate has an in-plane retardation value of -20 nm to 20 nm at a wavelength of 550 nm and a thickness-direction retardation value of -300 nm to 0 nm. In this way, the problem of halo caused by local dimming using a MiniLED backlight can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of liquid crystal displays, and in particular to an in-plane switching liquid crystal display. Background Art

[0002] In-Plane Switching Liquid Crystal Displays (IPS-LCDs) are one of the most popular displays on the market. When the voltage in an IPS-LCD is off, the liquid crystals in the panel do not rotate. At normal viewing angles, light passing through the polarizer is completely absorbed by the analyzer, achieving a perfect dark state. However, at oblique viewing angles, the effective angle between the absorption axes of the two polarizers is no longer perpendicular, causing light leakage and making the image appear white. Recently, to improve the contrast of IPS-LCDs, an increasing number of displays are using MiniLED backlights for local dimming.

[0003] However, MiniLED lamp beads are only around 200μm in size, making it easy to create hundreds or even thousands of backlight zones on large displays for precise dimming. By controlling the logic switches, MiniLEDs are turned on and off separately for bright and dark images. However, when both bright and dark images are displayed in the same backlight zone, the backlight in the corresponding zone will often illuminate, causing a small amount of light to bleed through the dark image, creating a halo effect and affecting the visual experience. Summary of the Invention

[0004] This application is proposed to address the above-mentioned technical problems existing in the prior art. This application aims to provide an in-plane switching liquid crystal display that can improve the contrast and color shift at both front and side viewing angles, and can solve the light source problem caused by the use of MiniLED backlights.

[0005] According to a first solution of the present application, an in-plane switching liquid crystal display is provided, comprising: a MiniLED backlight source, a first polarizer adjacent to the MiniLED backlight source, a liquid crystal unit having a liquid crystal with a positive dielectric constant or a negative dielectric constant, and a second polarizer, wherein the liquid crystal unit is located between the first polarizer and the second polarizer, and the absorption axes of the first polarizer and the second polarizer are perpendicular to each other, and the optical axis direction of the liquid crystal unit is parallel to the absorption axis of the first polarizer; the first polarizer and the second polarizer each comprise a first protective film, a polarizing film, and a second protective film, the polarizing film being located between the first protective film and the second protective film, and the first protective film being close to the first protective film. Liquid crystal unit; the first protective film on the second polarizer includes at least one negative biaxial retardation film and at least one positive C plate, the first protective film on the first polarizer includes at least one positive C plate, and the direction of the optical axis of the negative biaxial retardation film relative to the direction of the absorption axis of the second polarizer is determined based on the positional relationship between the negative biaxial retardation film and the second polarizer; the in-plane retardation value of the negative biaxial retardation film at a wavelength of 550nm is 50nm~250nm, and the thickness direction retardation value is 60nm~260nm; the in-plane retardation value of the positive C plate at a wavelength of 550nm is -20nm~20nm, and the thickness direction retardation value is -300nm~0nm.

[0006] Compared with the prior art, the embodiments of the present application have the following advantages:

[0007] The in-plane switching liquid crystal display provided in the embodiment of the present application uses a compensation material to replace the first protective film, or adjusts the optical path together with the first protective film. The compensation material includes a negative biaxial retardation film and a positive C plate. Among them, the negative biaxial retardation film and the positive C plate have good light transmittance, with a transmittance exceeding 88%, and will not affect the original optical properties such as transmittance and polarization of the first polarizer and the second polarizer. The negative biaxial retardation film provided in the embodiment of the present application has an in-plane retardation value of 50nm to 250nm at a wavelength of 550nm, and a thickness direction retardation value of 60nm to 260nm. The positive C plate has an in-plane retardation value of -20nm to 20nm at a wavelength of 550nm, and a thickness direction retardation value of -300nm to 0nm. In this way, the in-plane switching liquid crystal display prepared based on the negative biaxial retardation film and the positive C plate can improve the contrast of the front and side viewing angles, reduce the color change with the viewing angle, and improve the halo phenomenon caused by the MiniLED backlight source.

[0008] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above description and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar components in different views. Similar reference numerals with letter suffixes or different letter suffixes may represent different examples of similar components. The accompanying drawings generally illustrate various embodiments by way of example and not by way of limitation, and together with the description and claims, serve to illustrate the disclosed embodiments. Such embodiments are illustrative and exemplary and are not intended to be exhaustive or exclusive embodiments of the present method, apparatus, system, or non-transitory computer-readable medium having instructions for implementing the method.

[0010] FIG1( a ) shows a schematic diagram of the basic structure of an in-plane switching liquid crystal display provided according to an embodiment of the present application.

[0011] FIG1( b ) shows a schematic structural diagram of a polarizer provided according to an embodiment of the present application.

[0012] Figure 2 A first structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0013] Figure 3 A second structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0014] Figure 4 A third structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0015] Figure 5 A fourth structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0016] Figure 6 A fifth structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0017] Figure 7 A sixth structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0018] Figure 8 A seventh structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown.

[0019] Figure 9 An eighth structural schematic diagram of an in-plane switching liquid crystal display provided according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific embodiments, but are not intended to limit the present application.

[0021] The words "first", "second" and similar terms used in this application do not indicate any order, quantity or importance, but are only used to distinguish. The words "include" or "comprises" and similar terms used in this application mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of covering other elements. In this application, the arrows shown in the figures of each step are only examples of the execution order, not limitations. The technical solution of this application is not limited to the execution order described in the embodiments. The steps in the execution order can be combined, decomposed, or swapped, as long as the logical relationship of the execution content is not affected.

[0022] All terms (including technical or scientific terms) used in this application have the same meaning as those understood by ordinary technicians in the field to which this application belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense unless explicitly defined as such here. Techniques and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the techniques and equipment should be considered as part of the specification.

[0023] Figure 1(a) shows a schematic diagram of the basic structure of an in-plane switching liquid crystal display provided according to an embodiment of the present application. The in-plane switching liquid crystal display includes a MiniLED backlight 101, a first polarizer 102 adjacent to the MiniLED backlight 101, a liquid crystal cell 103 having a liquid crystal with a positive dielectric constant (Δε>0) or a negative dielectric constant (Δε<0), and a second polarizer 104. The liquid crystal cell 103 is located between the first polarizer 102 and the second polarizer 104, and the absorption axes of the first polarizer 102 and the second polarizer 104 are perpendicular to each other. The optical axis of the liquid crystal cell 103 is parallel to the absorption axis of the first polarizer 102.

[0024] MiniLED backlights 101 are a relatively new display technology that began industrialization in 2018 and, after several years of technological development, have gradually penetrated the high-end display field. Compared to traditional LED backlights, they offer higher brightness, better contrast, and more precise local dimming capabilities. MiniLED backlights 101 typically measure 100 to 200 microns, significantly smaller than traditional LEDs but slightly larger than MicroLEDs. Due to their small size, more MiniLEDs can be placed in a display backlight module of the same size, thereby improving display quality.

[0025] However, the inventors of this application discovered that when using the MiniLED backlight 101, a small amount of light seeps into a black screen, creating a halo phenomenon. This halo phenomenon only exists when using the MiniLED backlight 101 and does not occur with other backlight sources. Traditional backlights use a single switch to turn the backlight on or off, without a clear boundary between bright and dark areas, so there is no halo phenomenon. Therefore, improving or reducing the halo phenomenon has become a technical problem that needs to be solved for light path adjustment using the MiniLED backlight 101.

[0026] The first polarizer 102 is equivalent to a polarizer, and its function is to convert the light provided by the MiniLED backlight source 101 into polarized light. The second polarizer 104 is equivalent to an analyzer, which can absorb polarized light in a direction parallel to the transmission axis of the first polarizer 102.

[0027] The liquid crystal cell 103 is located between the first polarizer 102 and the second polarizer 104. The arrangement of the liquid crystal molecules can be controlled by applying different voltages to the electrodes of the liquid crystal cell 103. Generally speaking, the MiniLED backlight 101 provides a light source, and the emitted light passes through the first polarizer 102, allowing only light in a specific direction to pass through. When light passes through the liquid crystal cell 103, if no voltage is applied, the liquid crystal molecules in the liquid crystal cell 103 naturally align, allowing the light to continue to pass through the second polarizer 104. If a voltage is applied, the arrangement of the liquid crystal molecules in the liquid crystal cell 103 is changed, thereby changing the state of light passing through the liquid crystal layer. Finally, the light passes through the second polarizer 104 and reaches the surface of the display to form the final image.

[0028] The design in which the absorption axes of the first polarizer 102 and the second polarizer 104 are perpendicular to each other helps ensure that the liquid crystal layer of the liquid crystal unit 103 can change the polarization state of light according to the applied electric field, thereby controlling the degree of light transmittance, and can effectively utilize the optical effects of liquid crystal molecules under the action of the electric field to achieve high-quality image display.

[0029] As shown in Figure 1(b), the first polarizer 102 and the second polarizer 104 each include a first protective film 105, a polarizing film 106, and a second protective film 107. The polarizing film 106 is located between the first protective film 105 and the second protective film 107, and the first protective film 105 is close to the liquid crystal unit 103. The polarizer is a fragile optical component that is susceptible to mechanical scratches or chemical corrosion. The protective film can effectively prevent direct damage to the polarizer from these external factors and extend its service life. In addition, the protective film can also improve the optical transmittance and contrast of the polarizer, which can improve the visual quality and user experience of the display device.

[0030] The first protective film 105 on the second polarizer 104 includes at least one negative biaxial retardation film and at least one positive C plate, and the first protective film 105 on the first polarizer 102 includes at least one positive C plate, and the direction of the optical axis of the negative biaxial retardation film relative to the direction of the absorption axis of the second polarizer 104 is determined based on the positional relationship between the negative biaxial retardation film and the second polarizer 104. A negative biaxial retardation film and a positive C plate having a specific optical retardation range can be used as compensation materials to replace the first protective film 105 or adjust the optical path together with the first protective film 105. The compensation material can be composited with other components of the first polarizer 102 and the second polarizer 104 by roll-to-roll lamination. The use of the compensation material has no adverse effect on the original optical properties of the first polarizer 102 and the second polarizer 104, such as transmittance and polarization degree.

[0031] Specifically, a negative biaxial retardation film and a positive C-plate are disposed between the second polarizer 104 and the liquid crystal cell 103. The negative biaxial retardation film or the positive C-plate can replace the first protective film 105 of the second polarizer 104, or can be attached to the first protective film 105 to adjust the optical path. The placement of the negative biaxial retardation film and the positive C-plate is not limited. For example, the negative biaxial retardation film can be adjacent to the second polarizer 104, or a positive C-plate can be disposed between the negative biaxial retardation film and the second polarizer 104. This is merely an example.

[0032] The negative biaxial retardation film has an in-plane retardation value of 50nm to 250nm at a wavelength of 550nm, and a thickness-direction retardation value of 60nm to 260nm. The positive C-plate has an in-plane retardation value of -20nm to 20nm at a wavelength of 550nm, and a thickness-direction retardation value of -300nm to 0nm. An in-plane switching liquid crystal display fabricated using this negative biaxial retardation film and positive C-plate within this specific retardation range can improve contrast and color shift at both front and side viewing angles when using the MiniLED backlight 101, effectively reducing the halo phenomenon caused by the MiniLED backlight 101.

[0033] The in-plane retardation value (Rin) and the thickness direction retardation value (Rth) in this application are defined as follows: Rin = (nx - ny) × d;

[0034] Rth = {(nx + ny) / 2 - nz} × d;

[0035] nx, ny, and nz are the refractive indices of the retardation film in the x-axis direction, the y-axis direction, and the z-axis direction, respectively, and d is the thickness of the retardation film.

[0036] In some embodiments of the present application, the negative biaxial retardation film has an in-plane retardation value of 100nm to 150nm at a wavelength of 550nm, and a thickness direction retardation value of 75nm to 110nm; the positive C plate has an in-plane retardation value of -10nm to 10nm at a wavelength of 550nm, and a thickness direction retardation value of -150nm to -100nm. The inventors of the present application have discovered that the negative biaxial retardation film and the positive C plate in this specific retardation value range can be used as compensation materials to more effectively adjust the optical path, reduce the amount of light leakage, and further reduce the halo phenomenon, and the weak halo produced can be ignored. Moreover, after simulation verification, when the retardation values ​​of the negative biaxial retardation film and the positive C plate exceed the specific retardation range provided in this embodiment, the halo phenomenon produced is still obvious and cannot be ignored, affecting the viewing experience.

[0037] Preferably, the in-plane retardation value of the negative biaxial retardation film at a wavelength of 550nm is 130nm, and the retardation value in the thickness direction is 100nm. The in-plane retardation value of the positive C plate at a wavelength of 550nm is 0.1nm, and the retardation value in the thickness direction is -140nm. In this way, the contrast of the simulated in-plane switching liquid crystal display at an inclination angle of 70° can reach 155, which can effectively improve the halo phenomenon caused by the MiniLED backlight source 101.

[0038] In some embodiments of the present application, the optical axis of the liquid crystal unit 103 is parallel to the direction of the absorption axis of the first polarizer 102. The optical axis of the liquid crystal unit 103 is parallel to the direction of the absorption axis of the first polarizer 102, which can maximize the use of the birefringence characteristics of the liquid crystal unit 103, and also helps to optimize the optical performance and display effect of the liquid crystal display, ensuring that the polarization state of light can be effectively controlled, thereby achieving high-quality image display.

[0039] When the negative biaxial retardation film is adjacent to the second polarizer 104, the optical axis of the negative biaxial retardation film is perpendicular to the absorption axis direction of the second polarizer 104. When the negative biaxial retardation film is not adjacent to the second polarizer 104, the optical axis of the negative biaxial retardation film is parallel to the absorption axis direction of the second polarizer 104. In this way, light leakage at the tilt angle can be effectively reduced.

[0040] Specifically, Figure 2 The structure of an in-plane switching liquid crystal display (IPS) is shown. A negative biaxial retardation film 108 and a positive C-plate 109 are disposed between a liquid crystal cell 103 and a second polarizer 104. The negative biaxial retardation film 108 is adjacent to the second polarizer 104, and the positive C-plate 109 is disposed between the negative biaxial retardation film 108 and the liquid crystal cell 103. The liquid crystals in the liquid crystal cell 103 are arranged perpendicular to the horizontal plane. Specifically, this perpendicular arrangement of the liquid crystals in the liquid crystal cell 103 maintains good contrast and color performance despite changes in viewing angle. The rotation of the liquid crystal molecules more effectively controls the polarization of light, reducing light leakage at wide viewing angles.

[0041] In this embodiment, the negative biaxial retardation film 108 is adjacent to the second polarizer 104. Since the absorption axis and the transmission axis of the second polarizer 104 are at right angles, the optical axis of the negative biaxial retardation film 108 is perpendicular to the absorption axis of the second polarizer 104. The absorption axis of the second polarizer 104 is perpendicular to the optical axis of the liquid crystal unit 103, which can reduce light leakage caused by the crossed second polarizers 104.

[0042] In some embodiments of the present application, Figure 3 A negative biaxial retardation film 108 and a positive C-plate 109 are disposed between the liquid crystal cell 103 and the second polarizer 104. The negative biaxial retardation film 108 is adjacent to the liquid crystal cell 103, and the positive C-plate 109 is between the negative biaxial retardation film 108 and the second polarizer 104. The liquid crystals in the liquid crystal cell 103 are aligned perpendicular to the horizontal plane. The second polarizer 104 is adjacent to the positive C-plate 109, and the negative biaxial retardation film 108 is adjacent to the liquid crystal cell 103. The absorption axis of the second polarizer 104 is parallel to the optical axis of the negative biaxial retardation film 108, and the optical axis of the liquid crystal cell 103 is perpendicular to the optical axis of the negative biaxial retardation film 108. The negative biaxial retardation film 108 and the positive C-plate serve as compensation materials and are placed between the second polarizer 104 and the liquid crystal cell 103. By adjusting the direction of the optical axis of the negative biaxial retardation film 108, color shift with viewing angle can be reduced.

[0043] The positive C plate 109 has a retardation value in the thickness direction of -300nm to 0nm. The positive C plate 109 can be split into a first positive C plate and a second positive C plate, and the sum of the retardation values ​​in the thickness direction of the first positive C plate and the second positive C plate is made to be -300nm to 0nm. Specifically, Figure 4As shown, a negative biaxial retardation film 108 and a first positive C-plate 1091 are arranged between the liquid crystal unit 103 and the second polarizer 104, wherein the negative biaxial retardation film 108 is adjacent to the second polarizer 104, and the first positive C-plate 1091 is between the negative biaxial retardation film 108 and the liquid crystal unit 103, and the liquid crystal of the liquid crystal unit 103 is arranged perpendicular to the horizontal plane; a second positive C-plate 1092 is arranged between the liquid crystal unit 103 and the first polarizer 102, wherein the sum of the thickness direction retardation values ​​of the first positive C-plate 1091 and the second positive C-plate 1092 is -300nm to 0nm.

[0044] This structure of the LCD further improves display stability and makes dark details clearer, thanks to the second positive C-plate 1092 disposed between the liquid crystal cell 103 and the first polarizer 102. Furthermore, when used with the MiniLED backlight 101, it helps reduce the halo phenomenon caused by the MiniLED backlight 101.

[0045] When the first positive C-plate 1091 is located between the second polarizer 104 and the negative biaxial retardation film 108, the optical axis of the negative biaxial retardation film 108 is parallel to the absorption axis of the second polarizer 104, that is, an in-plane switching liquid crystal display is provided, wherein the negative biaxial retardation film 108 and the first positive C-plate 1091 are arranged between the liquid crystal unit 103 and the second polarizer 104, wherein the negative biaxial retardation film 108 is adjacent to the liquid crystal unit 103, the first positive C-plate 1091 is between the negative biaxial retardation film 108 and the second polarizer 104, the liquid crystal of the liquid crystal unit 103 is arranged perpendicular to the horizontal plane, and the second positive C-plate 1092 is arranged between the liquid crystal unit 103 and the first polarizer 102, wherein the sum of the thickness direction retardation values ​​of the first positive C-plate 1091 and the second positive C-plate 1092 is -300nm to 0nm.

[0046] In some other embodiments of the present application, an in-plane switching liquid crystal display is provided, such as Figure 6 A negative biaxial retardation film 108 and a positive C-plate 109 are disposed between the liquid crystal cell 103 and the second polarizer 104. The negative biaxial retardation film 108 is adjacent to the second polarizer 104, and the positive C-plate 109 is between the negative biaxial retardation film 108 and the liquid crystal cell 103. The liquid crystals in the liquid crystal cell 103 are arranged in a horizontal alignment. Horizontally aligned liquid crystal displays typically have faster response speeds. In a horizontal alignment, the rotation of liquid crystal molecules does not require significant resistance, allowing for faster transitions in polarization state.

[0047] When the liquid crystals of the liquid crystal cell 103 are arranged horizontally, the optical axis of the first polarizer 102 is parallel to the horizontal direction, and the absorption axis of the second polarizer 104 is perpendicular to the horizontal direction. Figure 6 The arrangement shown is simulated. When the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 84nm, the thickness direction retardation value is 171nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -204nm, and the in-plane retardation value is 10nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 87, and there is no obvious halo phenomenon; when the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 41nm, the thickness direction retardation value is 56nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -22nm, and the in-plane retardation value is 1nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 66, and there is a halo that cannot be ignored.

[0048] In some other embodiments of the present application, an in-plane switching liquid crystal display is provided, such as Figure 7 , a negative biaxial retardation film 108 and a positive C plate 109 are provided between the liquid crystal cell 103 and the second polarizer 104, wherein the negative biaxial retardation film 108 is adjacent to the liquid crystal cell 103, and the positive C plate 109 is between the negative biaxial retardation film 108 and the second polarizer 104, and the liquid crystal of the liquid crystal cell 103 is arranged in a horizontal manner. For example, based on Figure 7 The arrangement shown is simulated. When the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 115, the thickness direction retardation value is 99nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -125nm, and the in-plane retardation value is 3nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 160, and there is no obvious halo phenomenon; when the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 45nm, the thickness direction retardation value is 300nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -310nm, and the in-plane retardation value is 10nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 54, and there is a halo that cannot be ignored.

[0049] In some other embodiments of the present application, an in-plane switching liquid crystal display is provided, such as Figure 8, a negative biaxial retardation film 108 and a first positive C plate 1091 are provided between the liquid crystal unit 103 and the second polarizer 104, wherein the negative biaxial retardation film 108 is adjacent to the second polarizer 104, the first positive C plate 1091 is between the negative biaxial retardation film 108 and the liquid crystal unit 103, the liquid crystal of the liquid crystal unit 103 is arranged in a horizontal arrangement, and a second positive C plate 1092 is provided between the liquid crystal unit 103 and the first polarizer 102, wherein the sum of the thickness direction retardation values ​​of the first positive C plate 1091 and the second positive C plate 1092 is -300nm to 0nm. Exemplarily, based on Figure 8 The arrangement shown is simulated. When the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 117nm, the thickness direction retardation value is 103nm, and the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -120nm, and the in-plane retardation value is -2nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 113, and there is no obvious halo phenomenon; when the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 150nm, the thickness direction retardation value is 10nm, and the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is 30nm, and the in-plane retardation value is 10nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 91, and there is a non-negligible halo.

[0050] In some other embodiments of the present application, an in-plane switching liquid crystal display is provided, such as Figure 9 , a negative biaxial retardation film 108 and a first positive C plate 1091 are provided between the liquid crystal unit 103 and the second polarizer 104, wherein the negative biaxial retardation film 108 is adjacent to the liquid crystal unit 103, the first positive C plate 1091 is between the negative biaxial retardation film 108 and the second polarizer 104, and the liquid crystal of the liquid crystal unit 103 is arranged in a horizontal manner; a second positive C plate 1092 is provided between the liquid crystal unit 103 and the first polarizer 102, wherein the sum of the thickness direction retardation values ​​of the first positive C plate 1091 and the second positive C plate 1092 is -300 to 0 nm. For example, based on Figure 9The arrangement shown is simulated. When the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 141nm, the thickness direction retardation value is 84nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is -104nm, and the in-plane retardation value is 1nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 138, and there is no obvious halo phenomenon; when the in-plane retardation value of the negative biaxial retardation film 108 at a wavelength of 550nm is 50nm, the thickness direction retardation value is -100nm, the thickness direction retardation value of the positive C plate 109 at a wavelength of 550nm is 30nm, and the in-plane retardation value is 10nm, the simulation results show that the minimum contrast at an inclination angle of 70° is 62, and there is a halo that cannot be ignored.

[0051] That is, when the liquid crystals of the liquid crystal unit 103 are aligned horizontally, preferably, the negative biaxial retardation film has an in-plane retardation value of 100nm to 130nm and a thickness-direction retardation value of 75nm to 110nm at a wavelength of 550nm, and the positive C-plate has a thickness-direction retardation value of -150nm to -100nm at a wavelength of 550nm. This improves the contrast of the liquid crystal display at tilted angles, effectively reduces light leakage at the boundary between the luminous area and the dark area at oblique viewing angles, and further reduces or even eliminates the halo generated by the MiniLED backlight 101.

[0052] In some embodiments of the present application, the negative biaxial retardation film is made of uniaxially stretched triacetyl cellulose, uniaxially stretched polynorbornene, biaxially stretched polycarbonate, uniaxially or biaxially stretched cycloolefin polymer or UV-cured liquid crystal film, and the positive C plate is made of a polymer material or a UV-cured liquid crystal film, so that the negative biaxial retardation film has good light transmittance. Preferably, the negative biaxial retardation film is prepared from one of biaxially stretched polycarbonate, uniaxially or biaxially stretched cycloolefin polymer, so as to further improve the light transmittance of the negative biaxial retardation film and ensure that the best impact speed and color reproduction are achieved in the liquid crystal display. In addition, these two materials have the advantage of stable phase difference, and can still achieve the same optical compensation effect as normal temperature in the case of backlight heating to ensure viewing angle stability.

[0053] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of their solutions) can be used in combination with each other. For example, those of ordinary skill in the art may use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features can be grouped together to simplify the application. This should not be interpreted as an intention that a disclosed feature that is not required to be protected is necessary for any claim. On the contrary, the subject matter of the present application may be less than all the features of a specific disclosed embodiment. Thus, the claims are incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently a separate embodiment, and it is considered that these embodiments can be combined with each other in various combinations or arrangements. The scope of this application should be determined with reference to the appended claims and the full scope of equivalents to which these claims are entitled.

[0054] The above embodiments are merely exemplary embodiments of the present application and are not intended to limit the scope of the present application. The scope of protection of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and scope of protection of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the scope of protection of the present application.

Claims

1. An in-plane switching liquid crystal display, characterized in that: include: A MiniLED backlight, a first polarizer adjacent to the MiniLED backlight, a liquid crystal unit having a liquid crystal with a positive dielectric constant or a negative dielectric constant, and a second polarizer, wherein the liquid crystal unit is located between the first polarizer and the second polarizer, and the absorption axes of the first polarizer and the second polarizer are perpendicular to each other, and the optical axis of the liquid crystal unit is parallel to the absorption axis of the first polarizer; The first polarizer and the second polarizer each include a first protective film, a polarizing film, and a second protective film, wherein the polarizing film is located between the first protective film and the second protective film, and the first protective film is close to the liquid crystal unit; The first protective film on the second polarizer includes at least one negative biaxial retardation film and at least one positive C-plate, the first protective film on the first polarizer includes at least one positive C-plate, and the direction of the optical axis of the negative biaxial retardation film relative to the direction of the absorption axis of the second polarizer is determined based on the positional relationship between the negative biaxial retardation film and the second polarizer; The negative biaxial retardation film has an in-plane retardation value of 100nm to 150nm at a wavelength of 550nm, and a thickness direction retardation value of 75nm to 100nm; The positive C plate has an in-plane retardation value of 1 nm to 10 nm at a wavelength of 550 nm, and a thickness direction retardation value of -150 nm to -100 nm.

2. The in-plane switching liquid crystal display according to claim 1, wherein The optical axis of the liquid crystal unit is parallel to the absorption axis of the first polarizer, and In the case where the negative biaxial retardation film is adjacent to the second polarizer, the optical axis of the negative biaxial retardation film is perpendicular to the absorption axis direction of the second polarizer. In a case where the negative biaxial retardation film is not adjacent to the second polarizer, the optical axis of the negative biaxial retardation film is parallel to the absorption axis direction of the second polarizer.

3. The in-plane switching liquid crystal display according to claim 2, wherein: A negative biaxial retardation film and a positive C-plate are arranged between the liquid crystal unit and the second polarizer, wherein the negative biaxial retardation film is adjacent to the second polarizer, and the positive C-plate is between the negative biaxial retardation film and the liquid crystal unit, and the liquid crystal of the liquid crystal unit is arranged perpendicular to the horizontal plane.

4. The in-plane switching liquid crystal display according to claim 2, wherein: A negative biaxial retardation film and a positive C-plate are arranged between the liquid crystal unit and the second polarizer, wherein the negative biaxial retardation film is adjacent to the liquid crystal unit, and the positive C-plate is between the negative biaxial retardation film and the second polarizer, and the liquid crystal of the liquid crystal unit is arranged perpendicular to the horizontal plane.

5. The in-plane switching liquid crystal display according to claim 2, wherein: The positive C plate includes a first positive C plate and a second positive C plate; A negative biaxial retardation film and a first positive C-plate are provided between the liquid crystal cell and the second polarizer, wherein the negative biaxial retardation film is adjacent to the second polarizer, and the first positive C-plate is between the negative biaxial retardation film and the liquid crystal cell, and the liquid crystals of the liquid crystal cell are arranged perpendicular to the horizontal plane; A second positive C plate is provided between the liquid crystal unit and the first polarizer, wherein the sum of thickness direction retardation values ​​of the first positive C plate and the second positive C plate is -300 nm to 0 nm.

6. The in-plane switching liquid crystal display according to claim 2, wherein: The positive C plate includes a first positive C plate and a second positive C plate; A negative biaxial retardation film and a first positive C-plate are provided between a liquid crystal cell and a second polarizer, wherein the negative biaxial retardation film is adjacent to the liquid crystal cell, the first positive C-plate is between the negative biaxial retardation film and the second polarizer, and the liquid crystals of the liquid crystal cell are arranged perpendicular to a horizontal plane; A second positive C plate is provided between the liquid crystal unit and the first polarizer, wherein the sum of thickness direction retardation values ​​of the first positive C plate and the second positive C plate is -300 nm to 0 nm.

7. The in-plane switching liquid crystal display according to claim 2, wherein: A negative biaxial retardation film and a positive C-plate are arranged between the liquid crystal unit and the second polarizer, wherein the negative biaxial retardation film is adjacent to the second polarizer, and the positive C-plate is between the negative biaxial retardation film and the liquid crystal unit, and the liquid crystal of the liquid crystal unit is arranged horizontally.

8. The in-plane switching liquid crystal display according to claim 2, wherein: A negative biaxial retardation film and a positive C-plate are arranged between the liquid crystal unit and the second polarizer, wherein the negative biaxial retardation film is adjacent to the liquid crystal unit, and the positive C-plate is between the negative biaxial retardation film and the second polarizer, and the liquid crystal of the liquid crystal unit is arranged horizontally.

9. The in-plane switching liquid crystal display according to claim 2, wherein: The positive C plate includes a first positive C plate and a second positive C plate; A negative biaxial retardation film and a first positive C-plate are provided between the liquid crystal cell and the second polarizer, wherein the negative biaxial retardation film is adjacent to the second polarizer, and the first positive C-plate is between the negative biaxial retardation film and the liquid crystal cell, and the liquid crystal of the liquid crystal cell is arranged in a horizontal manner; A second positive C plate is provided between the liquid crystal unit and the first polarizer, wherein the sum of thickness direction retardation values ​​of the first positive C plate and the second positive C plate is -300 nm to 0 nm.

10. The in-plane switching liquid crystal display according to claim 2, wherein: The positive C plate includes a first positive C plate and a second positive C plate; A negative biaxial retardation film and a first positive C-plate are provided between the liquid crystal cell and the second polarizer, wherein the negative biaxial retardation film is adjacent to the liquid crystal cell, the first positive C-plate is between the negative biaxial retardation film and the second polarizer, and the liquid crystal of the liquid crystal cell is arranged in a horizontal manner; A second positive C plate is provided between the liquid crystal unit and the first polarizer, wherein the sum of thickness direction retardation values ​​of the first positive C plate and the second positive C plate is -300 nm to 0 nm.

11. The in-plane switching liquid crystal display according to any one of claims 1 to 10, characterized in that: The negative biaxial retardation film is made of uniaxially stretched triacetyl cellulose, uniaxially stretched polynorbornene, biaxially stretched polycarbonate, uniaxially or biaxially stretched cycloolefin polymer or UV-cured liquid crystal film; the positive C plate is made of polymer material or UV-cured liquid crystal film.

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