Display device

Abstract

An embodiment of the present application discloses a display device, which has a narrow-view anti-peeping mode and a wide-view sharing mode. The display device includes a backlight module, a first dimming box, a second dimming box, and a liquid crystal display module. The first dimming box is disposed on the light-emitting side of the backlight module; the second dimming box is disposed on the light-emitting side of the first dimming box; the liquid crystal display module is disposed on the light-emitting side of the second dimming box; the color coordinate offset between the color coordinates at a 45° side view angle in the anti-peeping mode and the color coordinates at a front view angle in the anti-peeping mode is less than 0.1869. Among them, in the side view angle of the anti-peeping mode, the embodiment of the present application adjusts the second dimming box to reduce the gap in the ratio of red, green, and blue light, thereby improving the phenomenon of color difference between the side view angle and the front view angle of the display device in the anti-peeping mode.

Description

Technical Field

[0001] This application relates to the field of display technology, and particularly to a display device. Background Art

[0002] Currently, for a display device with a switchable anti-peeking display function, the main technology is to add a dimming device between the display panel and the backlight module. One type of liquid crystal dimming technology changes the polarization state of the light passing through it by controlling the angle between the liquid crystal axis and the light passing through it, and then further controls the transmittance of the incident light from different angles of the backlight module by the polarizer on the dimming device, so as to make the outgoing light of the display device have a narrow viewing angle.

[0003] In order to improve the anti-peeking display effect, generally multiple dimming cells are stacked in the same box thickness and with the same driving voltage. However, for the additionally added second dimming cell, not only the light collection ratio does not increase exponentially compared to the first dimming cell, but also due to the liquid crystal dispersion effect, it will exacerbate the color difference between the side-viewing angle image and the front-viewing angle image in the anti-peeking mode. For example, the existing technology dimming cell generally refers to the dimming ability of the liquid crystal at a wavelength of 589 nanometers, which results in the designed dimming cell having the best modulation effect on the incident light at 589 nanometers. When multiple identical dimming cells are stacked to improve the anti-peeking effect of the display device, it will cause a serious imbalance in the ratio of red, green, and blue lights emitted in the side-viewing angle direction in the anti-peeking mode of the display device, that is, no matter what image is displayed in the front-viewing direction, the overall image in the side-viewing angle direction will appear bluish or reddish. Summary of the Invention

[0004] An embodiment of this application provides a display device, which can reduce the risk of color difference between the side-viewing angle image and the front-viewing angle image in the anti-peeking mode.

[0005] An embodiment of this application provides a display device, which has an anti-peeking mode with a narrow viewing angle and a sharing mode with a wide viewing angle. The display device includes:

[0006] A backlight module;

[0007] A first dimming cell, which is arranged on the light-emitting side of the backlight module;

[0008] A second dimming cell, which is arranged on the light-emitting side of the first dimming cell;

[0009] A liquid crystal display module, which is arranged on the light-emitting side of the second dimming cell;

[0010] The color coordinate offset between the color coordinates at the 45° side viewing angle in the anti-peeking mode and the color coordinates at the front viewing angle in the anti-peeking mode is less than 0.1869.

[0011] Optionally, in some embodiments of the present application, the first dimming box includes a first substrate, a first liquid crystal layer, and a second substrate that are sequentially stacked, the first substrate is disposed on the side close to the backlight module, the second dimming box includes a third substrate, a second liquid crystal layer, and a fourth substrate that are sequentially stacked, and the third substrate is disposed on the side close to the first dimming box;

[0012] The first substrate is disposed on the side close to the backlight module. The thickness of the first liquid crystal layer is equal to the thickness of the second liquid crystal layer, the refractive index difference Δn of the first liquid crystal layer is the same as the refractive index difference Δn of the second liquid crystal layer, and the first driving voltage applied to the first dimming box is different from the second driving voltage applied to the second dimming box.

[0013] Optionally, in some embodiments of the present application, the first driving voltage and the second driving voltage are alternating voltages, the thicknesses of the first liquid crystal layer and the second liquid crystal layer are between 4 microns and 8 microns, the amplitude of the first driving voltage is between 3.5 volts and 5.5 volts, the amplitude of the second driving voltage is between 4 volts and 7 volts, and the frequencies of the first driving voltage and the second driving voltage are both between 40 Hz and 120 Hz.

[0014] Optionally, in some embodiments of the present application, the first dimming box includes a first substrate, a first liquid crystal layer, and a second substrate that are sequentially stacked, the first substrate is disposed on the side close to the backlight module, the second dimming box includes a third substrate, a second liquid crystal layer, and a fourth substrate that are sequentially stacked, and the third substrate is disposed on the side close to the first dimming box;

[0015] The thickness of the first liquid crystal layer is different from the thickness of the second liquid crystal layer, the refractive index difference Δn of the first liquid crystal layer is different from the refractive index difference Δn of the second liquid crystal layer, and the first driving voltage applied to the first dimming box is different from the second driving voltage applied to the second dimming box.

[0016] Optionally, in some embodiments of the present application, the thickness of the first liquid crystal layer is greater than the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is less than the refractive index difference Δn of the second liquid crystal layer; or

[0017] The thickness of the first liquid crystal layer is less than the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is greater than the refractive index difference Δn of the second liquid crystal layer.

[0018] Optionally, in some embodiments of the present application, the thickness of the first liquid crystal layer and the thickness of the second liquid crystal layer are both between 2 micrometers and 10 micrometers, and the refractive index difference Δn of the first liquid crystal layer and the refractive index difference Δn of the second liquid crystal layer are both between 0.1 and 0.26.

[0019] Optionally, in some embodiments of the present application, the amplitude of the first driving voltage is the optimal driving voltage amplitude, and the amplitude of the second driving voltage is the non-optimal driving voltage amplitude.

[0020] Optionally, in some embodiments of the present application, the amplitude of the first driving voltage is the non-optimal driving voltage amplitude, and the amplitude of the second driving voltage is the non-optimal driving voltage amplitude.

[0021] Optionally, in some embodiments of the present application, the display device further includes a first polarizer, a second polarizer, and an anti-peeking film. The liquid crystal display module includes a liquid crystal panel, a third polarizer, and a fourth polarizer. The fourth polarizer is disposed on a side of the liquid crystal panel away from the backlight module, the third polarizer is disposed on a side of the liquid crystal panel close to the backlight module, the second polarizer is disposed between the first light modulation box and the second light modulation box, and the first polarizer is disposed on a side of the first light modulation box close to the backlight module;

[0022] The anti-peeking film is disposed between any two of the backlight module, the first polarizer, the first light modulation box, the second polarizer, the second light modulation box, the third polarizer, the liquid crystal panel, and the fourth polarizer;

[0023] The anti-peeking film is configured such that the reflectivity of the anti-peeking film has a positive correlation with the incident angle of light.

[0024] Optionally, in some embodiments of the present application, the anti-peeking film includes a plurality of stacked light-transmitting films, and the refractive indices of any two adjacent light-transmitting films are different.

[0025] Optionally, in some embodiments of the present application, the display device further includes a third light modulation box, the third light modulation box is disposed between the first light modulation box and the liquid crystal display module, and the color coordinate offset between the color coordinates of the anti-peeking mode at a 45° side viewing angle and the color coordinates of the anti-peeking mode at a front viewing angle is less than 0.1869.

[0026] Optionally, in some embodiments of the present application, in the sharing mode, neither the first light modulation box nor the second light modulation box is connected to a driving voltage.

[0027] An embodiment of the present application provides a display device, which has a narrow viewing angle anti-peeking mode and a wide viewing angle sharing mode. The display device includes a backlight module, a first dimming box, a second dimming box, and a liquid crystal display module. The first dimming box is disposed on the light-emitting side of the backlight module; the second dimming box is disposed on the light-emitting side of the first dimming box; the liquid crystal display module is disposed on the light-emitting side of the second dimming box; in the side viewing angle of the anti-peeking mode, the second dimming box is used to reduce the color light with the highest brightness emitted by the first dimming box. Among them, in the side viewing angle of the anti-peeking mode, the embodiment of the present application adjusts the first dimming box and the second dimming box to reduce the gap in the ratio of red, green, and blue light, so that the color coordinates at 45 degrees in the anti-peeking mode of the display device are closer to the color coordinates at the front view (0 degrees) viewing angle in the anti-peeking mode, thereby improving the phenomenon of color difference between the side viewing angle and the front viewing angle of the display device in the anti-peeking mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the display device provided by the embodiment of the present application;

[0029] Figure 2 is a spectrogram corresponding to the front view and the 45-degree viewing angle in the sharing mode (WVA) and the anti-peeking mode (NVA) of the comparative example;

[0030] Figure 3 is a chromaticity coordinate diagram corresponding to the front view and the 45-degree viewing angle in the sharing mode (WVA) and the anti-peeking mode (NVA) of the comparative example;

[0031] Figure 4 is a relationship diagram of the optical wavelength corresponding to the refractive index value Δn of two different liquid crystals;

[0032] Figure 5 is a timing diagram of a first driving voltage and a second driving voltage of the display device provided by the embodiment of the present application;

[0033] Figure 6 is another timing diagram of a first driving voltage and a second driving voltage of the display device provided by the embodiment of the present application;

[0034] Figure 7 is a light receiving effect diagram of the embodiment of the present application and the comparative example in the anti-peeking mode (NVA);

[0035] Figure 8 is a chromaticity point coordinate diagram of the front view and the 45-degree viewing angle of the embodiment of the present application and the comparative example in the anti-peeking mode (NVA);

[0036] Figure 9 is a schematic structural diagram of the anti-peeking film of the display device provided by the embodiment of the present application;

[0037] Figure 10 is another schematic structural diagram of the display device provided by the embodiment of the present application. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; and "inner" and "outer" refer to the outline of the device; the terms "first", "second", "third", etc. are only used as labels, and do not impose numerical requirements or establish an order.

[0039] An embodiment of the present application provides a display device, which will be described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments.

[0040] Please refer to Figure 1 , an embodiment of the present application provides a display device 100, which has an anti-peeking mode with a narrow viewing angle and a sharing mode with a wide viewing angle. The display device 100 includes a backlight module 10, a first dimming box 20, a second dimming box 30, and a liquid crystal display module 40.

[0041] The first dimming box 20 is disposed on the light-emitting side of the backlight module 10. The second dimming box 30 is disposed on the light-emitting side of the first dimming box 20. The liquid crystal display module 40 is disposed on the light-emitting side of the second dimming box 30.

[0042] The color coordinate offset between the color coordinates at the 45° side viewing angle in the anti-peeking mode and the color coordinates at the front viewing angle in the anti-peeking mode is less than 0.1869.

[0043] An embodiment of the present application provides a display device 100. In the side viewing angle of the anti-peeking mode, in the embodiment of the present application, by adjusting the first dimming box 20 and the second dimming box 30, the difference in the proportion of red, green, and blue light is reduced, so that the color coordinates of the display device 100 are closer to the color coordinates at the front (0-degree) viewing angle in the anti-peeking mode, thereby improving the phenomenon of color difference between the side viewing angle and the front viewing angle of the display device 100 in the anti-peeking mode.

[0044] It should be noted that the color coordinate offset is the distance between the color coordinates at the front view (0 degrees) angle of the display device 100 in the anti-peeking mode and the color coordinates at the 45-degree angle in the anti-peeking mode. For example, the color coordinates at the 0-degree angle in the anti-peeking mode are the color coordinates of the white light point, and the color coordinates of the white light point are (0.333, 0.333). The color coordinate offset is the distance from any color point coordinate to the color coordinates of the white light point. Among them, the smaller the color coordinate offset, the closer the color coordinate point is to the white light point. Therefore, the closer the color point coordinates at the 45° side view angle in the anti-peeking mode are to the color coordinates of the white light point, the smaller the color difference between the side view angle and the front view angle in the anti-peeking mode, and the better the improvement effect.

[0045] In the related art, please refer to Figure 7 and Figure 8 When the driving voltages of the double dimming boxes (the first dimming box and the second dimming box) are both 5.1 volts, the percentage of the brightness at 45 degrees / the brightness at 0 degrees is 1.44%, and the light receiving effect of the display device is the best. However, at this time, the color point (0.305, 0.291) corresponding to the front view angle (0-degree angle) in the anti-peeking mode, and the color point coordinates at the 45° side view angle in the anti-peeking mode are the color point (0.199, 0.137), and its color coordinate offset is about 0.18695.

[0046] Among them, the main wavelength band of visible light is between 380 nanometers and 780 nanometers. In the side view direction, the transmittance of visible light with different wavelength bands through the thickness of one dimming box is different, and adjusting the driving voltage of the dimming box will affect the transmittance of visible light with different wavelength bands. Therefore, when visible light incident with white light passes through two identical dimming boxes and the driving voltages of the two dimming boxes are the same, the wavelength bands of visible light adjusted by the two dimming boxes are the same, and the light intensity ratios of different wavelength bands of the transmitted visible light are seriously unbalanced, so there are serious deviations in the color points of the transmitted light.

[0047] Embodiments of the present application improve the color difference by adjusting at least one of the driving voltage, the liquid crystal layer thickness, and the liquid crystal type of the first dimming box 20 and the second dimming box 30 respectively. For example, when the first dimming box 20 and the second dimming box 30 are the same dimming box, that is, when the thickness of the liquid crystal layer and the liquid crystal type are the same, the driving voltages of the first dimming box 20 and the second dimming box 30 can be adjusted. Because their driving voltages are different, the wavelength bands of visible light adjusted by the two dimming boxes are different. Therefore, compared with a display device with two identical dimming boxes and the same driving voltage, the change in the light intensity ratio of different wavelength bands of visible light adjusted by the two dimming boxes of the display device 100 of the present application is smaller, making the color point coordinates closer to the color coordinates of the white light point, thereby improving the phenomenon of color difference between the side view angle and the front view angle in the anti-peeking mode.

[0048] For another example, in the light emitted by the first dimming box 20, compared with the light intensity ratios of red, green, and blue lights in white light, the deviation of the light intensity ratio of blue light is the largest, that of red light is the second largest, and that of green light is the smallest. Then, the second dimming box 30 is used to reduce the light intensity ratio of blue light. If, in the light emitted by the first dimming box 20, the deviation of the light intensity ratio of red light is the largest, that of blue light is the second largest, and that of green light is the smallest, then the second dimming box 30 is used to reduce the light intensity ratio of red light.

[0049] It should be noted that white light is formed by mixing red, green, and blue lights according to a certain light intensity ratio. Therefore, the reference for the deviation of the light intensity ratio is the light intensity ratios of red, green, and blue lights in white light. Optionally, the light intensity ratios of red, green, and blue lights in white light can be 3:6:1. Among them, the mixing ratio of red, green, and blue lights in white light also needs to be appropriately adjusted according to the material conditions of the sub-pixels of the display panel itself.

[0050] In an embodiment, the display device 100 further includes a first polarizer 51 and a second polarizer 52. The liquid crystal display module 40 includes a liquid crystal panel 41, a third polarizer 42, and a fourth polarizer 43. The fourth polarizer 43 is disposed on a side of the liquid crystal panel 41 away from the backlight module 10. The third polarizer 42 is disposed on a side of the liquid crystal panel 41 close to the backlight module 10. The second polarizer 52 is disposed between the first dimming box 20 and the second dimming box 30. The first polarizer 51 is disposed on a side of the first dimming box 20 close to the backlight module 10.

[0051] The first dimming box 20 includes a first substrate 21, a first liquid crystal layer 22, and a second substrate 23 which are sequentially stacked. The first substrate 21 is disposed on a side close to the backlight module 10. The second dimming box 30 includes a third substrate 31, a second liquid crystal layer 32, and a fourth substrate 33 which are sequentially stacked, and the third substrate 31 is disposed on a side close to the first dimming box 20.

[0052] It can be understood that when the light is parallel to the polarization axis of the polarizer, the light can pass through the polarizer, and when the light is perpendicular to the polarization axis of the polarizer, it will be blocked.

[0053] Therefore, when the polarization axes of the first polarizer 51 and the second polarizer 52 are parallel, when the first dimming box 20 is not connected to the driving voltage, the light can naturally pass through the second polarizer 52. When the polarization axes of the first polarizer 51 and the second polarizer 52 are perpendicular, the first dimming box 20 needs to be connected to the driving voltage so that the liquid crystal in the first dimming box 20 deflects and the light can pass through the second polarizer 52.

[0054] That is to say, based on the design of the polarization axes of the first polarizer 51, the second polarizer 52, and the third polarizer 42, the driving modes of the first dimming box 20 and the second dimming box 30 can be appropriately adjusted.

[0055] This application is described by taking the example that the polarization axes of the first polarizer 51, the second polarizer 52, and the third polarizer 42 are parallel to each other, but it is not limited thereto.

[0056] Therefore, in the sharing mode, neither the first dimming box 20 nor the second dimming box 30 is connected to the driving voltage. In some embodiments, the first dimming box 20 and the second dimming box 30 may also be connected to an extremely weak voltage, such as 0.02 volts.

[0057] Optionally, the liquid crystal panel 41 may be a panel with a TN, VA, IPS, or FFS display architecture. This embodiment of the application is described by taking the liquid crystal panel 41 as an IPS panel as an example, but it is not limited thereto.

[0058] The liquid crystal panel 41 includes an array substrate 4a, liquid crystal 4b, and a color filter substrate 4c. The array substrate 4a includes a first substrate 411, a common electrode layer 412, an insulating layer 413, and pixel electrodes 414 that are sequentially stacked. The color filter substrate 4c includes a second substrate 415 and a color filter layer 416 provided on the side of the second substrate 415 close to the liquid crystal 4b.

[0059] Optionally, the first dimming box 20 and the second dimming box 30 may drive the liquid crystal to deflect with a vertical electric field, or may drive the liquid crystal to deflect with a horizontal electric field or a transverse electric field. When the two use a horizontal electric field or a transverse electric field for driving, the common electrode and the driving electrode are both provided on the same substrate.

[0060] Compared with a horizontal electric field or a transverse electric field, driving with a vertical electric field has a better anti-peeping effect and can reduce the risk of light leakage at large angles.

[0061] Therefore, optionally, the first dimming box 20 and the second dimming box 30 adopt an ECB or VA mode architecture. The first dimming box 20 further includes a first driving electrode 24, a first alignment film 25, a second driving electrode 26, and a second alignment film 27. The first driving electrode 24 is provided on the side of the first substrate 21 close to the first liquid crystal layer 22, and the first alignment film 25 is provided on the side of the first driving electrode 24 close to the first liquid crystal layer 22. The second driving electrode 26 is provided on the side of the second substrate 23 close to the first liquid crystal layer 22, and the second alignment film 27 is provided on the side of the second driving electrode 26 close to the first liquid crystal layer 22.

[0062] The second dimming box 30 further includes a third driving electrode 34, a third alignment film 35, a fourth driving electrode 36, and a fourth alignment film 37. The third driving electrode 34 is provided on the side of the third substrate 31 close to the second liquid crystal layer 32, and the third alignment film 35 is provided on the side of the third driving electrode 34 close to the second liquid crystal layer 32. The fourth driving electrode 36 is provided on the side of the fourth substrate 33 close to the second liquid crystal layer 32, and the fourth alignment film 37 is provided on the side of the fourth driving electrode 36 close to the second liquid crystal layer 32.

[0063] Optionally, when the first dimming box 20 and the second dimming box 30 are in the ECB mode, the pretilt angles of the liquid crystals in the first liquid crystal layer 22 and the second liquid crystal layer 32 are between 0 degrees and 10 degrees. For example, they can be 0 degree, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees or 10 degrees, etc. When the first dimming box 20 and the second dimming box 30 are in the VA mode, the pretilt angles of the liquid crystals in the first liquid crystal layer 22 and the second liquid crystal layer 32 are between 87 degrees and 90 degrees. For example, they can be 87 degrees, 88 degrees, 89 degrees or 90 degrees, etc. Among them, setting the pretilt angle of the liquid crystal facilitates the liquid crystal to quickly respond to deflection and improves the response speed.

[0064] It should be noted that in the anti-peeping display device of the comparative example, the first dimming box and the second dimming box adopt the same design, that is, the same liquid crystal, the same cell thickness (the thickness of the liquid crystal layer) and the same driving voltage. This results in the spectra and color dots at the front view and the 45-degree side view in the anti-peeping mode (narrow viewing angle) and the sharing mode (wide viewing angle) in actual applications as Figure 2 and Figure 3 shown. In the sharing mode (WVA), the incident light rays at the front view and the side view are not regulated by the two dimming boxes. The light intensity ratio of red, green and blue light in the side-view outgoing light basically conforms to the white light ratio. Therefore, the color difference between the two is small. However, in the anti-peeping mode (NVA), after the side-view outgoing light is regulated by the two dimming boxes, due to the wavelength dispersion characteristic of the liquid crystal, the light intensity ratio of red, green and blue light in the side-view outgoing light is seriously unbalanced, and the color dots are severely deviated from the white light white point. Among them, it should be noted that in Figure 3 , the color dots at the front view (0 degree) in the sharing mode (WVA) partially coincide with the color dots at the front view (0 degree) in the anti-peeping mode (NVA).

[0065] In an embodiment of the present application, the first substrate 21 is disposed on the side close to the backlight module 10, and the thickness of the first liquid crystal layer 22 is equal to the thickness of the second liquid crystal layer 32. The refractive index difference Δn of the first liquid crystal layer 22 is the same as the refractive index difference Δn of the second liquid crystal layer 32. The first driving voltage V1 applied to the first dimming box 20 is different from the second driving voltage V2 applied to the second dimming box 30.

[0066] That is to say, in the embodiment of the present application, the first dimming box 20 and the second dimming box 30 are respectively driven by different driving voltages to reduce the difference in the proportion of the light intensity of the incident light in the red, green and blue light bands of the incident light in the side viewing angle direction and the incident light in the front viewing angle direction reaching the inside of the liquid crystal display module 40, and while maintaining the anti-peeping effect of the display device 100 in the anti-peeping mode unchanged, reducing the color difference between the side viewing angle direction and the front viewing angle.

[0067] It should be noted that the refractive index difference Δn of the liquid crystal refers to the refractive index difference of the liquid crystal at 589 nm (Δn = ne - no). The first driving voltage V1 refers to the voltage difference between the first driving electrode 24 and the second driving electrode 26, and the second driving voltage V2 refers to the voltage difference between the third driving electrode 34 and the fourth driving electrode 36.

[0068] In one embodiment, the thicknesses of the first liquid crystal layer 22 and the second liquid crystal layer 32 are between 4 microns and 8 microns. The refractive index differences Δn of the first liquid crystal layer 22 and the second liquid crystal layer 32 are both between 0.1 and 0.26.

[0069] It can be understood that, as Figure 4 , based on the wavelength dispersion characteristics of the liquid crystal, the distribution of the liquid crystal Δn in the visible light band decreases as the wavelength increases. The thickness of the liquid crystal layer has a certain influence on the spectral band of light, and the greater the thickness, the greater the influence. In addition, the greater the refractive index difference Δn of the liquid crystal, the smaller the cell thickness (the thickness of the liquid crystal layer) required for the dimming cell; the smaller the refractive index difference Δn of the liquid crystal, the greater the cell thickness required for the dimming cell. That is, the thicknesses of the first liquid crystal layer 22 and the second liquid crystal layer 32 are negatively correlated with their respective liquid crystal refractive index differences Δn.

[0070] Optionally, the thicknesses of the first liquid crystal layer 22 and the second liquid crystal layer 32 can each be 4 microns, 5 microns, 6 microns, 7 microns, or 8 microns, etc.

[0071] Optionally, the refractive index differences Δn of the first liquid crystal layer 22 and the second liquid crystal layer 32 can each be between 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, or 0.26, etc.

[0072] The first driving voltage V1 and the second driving voltage V2 are alternating voltages. The amplitude of the first driving voltage V1 is between 3.5 volts and 5.5 volts. The amplitude of the second driving voltage V2 is between 4 volts and 7 volts. The frequencies of the first driving voltage V1 and the second driving voltage V2 are both between 40 Hz and 120 Hz.

[0073] This application uses an alternating voltage to drive the first dimming cell 20 and the second dimming cell 30, which can reduce the risk of polarization of the liquid crystal in the first liquid crystal layer 22 and the second liquid crystal layer 32.

[0074] It should be understood that the higher the frequency, the higher the frequency of the driving voltage switching, the lower the risk of liquid crystal polarization, but the greater the power consumption. The greater the driving voltage, the greater the electric field strength formed, the faster the liquid crystal deflects, and the larger the deflection angle can be.

[0075] Among them, based on the selection of the thicknesses of the first liquid crystal layer 22 and the second liquid crystal layer 32, the first driving voltage V1, the second driving voltage V2, and the frequency, the light intensity ratios of the red, green, and blue lights of the light emitted from the side viewing angle are adjusted to reduce the color difference between the side viewing angle direction and the front viewing angle.

[0076] Optionally, the first driving voltage V1 can be 3.5 volts, 3.6 volts, 3.7 volts, 3.8 volts, 3.9 volts, 4 volts, 4.1 volts, 4.2 volts, 4.3 volts, 4.4 volts, 4.5 volts, 4.6 volts, 4.7 volts, 4.8 volts, 4.9 volts, 5 volts, 5.1 volts, 5.2 volts, 5.3 volts, 5.4 volts or 5.5 volts, etc.

[0077] The second driving voltage V2 can be 4 volts, 4.1 volts, 4.2 volts, 4.3 volts, 4.4 volts, 4.5 volts, 4.6 volts, 4.7 volts, 4.8 volts, 4.9 volts, 5 volts, 5.1 volts, 5.2 volts, 5.3 volts, 5.4 volts, 5.5 volts, 5.6 volts, 5.7 volts, 5.8 volts, 5.9 volts, 6 volts, 6.1 volts, 6.2 volts, 6.3 volts, 6.4 volts, 6.5 volts, 6.6 volts, 6.7 volts, 6.8 volts, 6.9 volts or 7 volts, etc.

[0078] The frequencies of the first driving voltage V1 and the second driving voltage V2 can each be 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, 100 Hz, 110 Hz or 120 Hz, etc.

[0079] In addition, optionally, the waveforms of the first driving voltage V1 and the second driving voltage V2 can be square waves, sine waves or triangular waves, etc. The pulse widths of the first driving voltage V1 and the second driving voltage V2 are the same. The first driving voltage V1 and the second driving voltage V2 can have a phase difference or can have no phase difference.

[0080] Compared with the display device of the comparative example (the driving voltage of the two dimming boxes is 5.1 V AC square wave), in the embodiment of the present application, taking the first driving voltage V1 as a 5 V square wave and the second driving voltage V2 as a 5.9 V square wave as an example, please refer to Figure 5 and Figure 6, that is, when the first driving electrode 24 is connected to a voltage of 5 V, the second driving electrode 26 is connected to a voltage of 0 V; when the first driving electrode 24 is connected to a voltage of 0 V, the second driving electrode 26 is connected to a voltage of 5 V; and they are alternately driven at a set frequency in this way. When the third driving electrode 34 is connected to a voltage of 5.9 V, the fourth driving electrode 36 is connected to a voltage of 0 V; when the third driving electrode 34 is connected to a voltage of 0 V, the fourth driving electrode 36 is connected to a voltage of 5.9 V; and they are alternately driven at a set frequency in this way.

[0081] Please refer to Figure 7 and Figure 8 , it should be understood that the smaller the percentage of the brightness at 45 degrees / the brightness at 0 degrees, the better the light-receiving effect of the display device. According to Figure 7 , it can be seen that in the display device of the comparative example, when the driving voltages of the double dimming boxes (the first dimming box and the second dimming box) are both 5.1 V, the percentage of the brightness at 45 degrees / the brightness at 0 degrees is 1.44%, and the light-receiving effect of the display device is the best. When the first driving voltage of the first dimming box 20 in the double dimming box is 5 V and the second driving voltage is 5.9 V, the percentage of the brightness at 45 degrees / the brightness at 0 degrees is also 1.44%, but the light-receiving effect of the display device 100 is not the best effect. It should be understood that the optimal driving voltage corresponds to the best light-receiving effect, that is, the percentage of the brightness at 45 degrees / the brightness at 0 degrees is the smallest.

[0082] According to Figure 8 , it can be seen that the color point (0.305, 0.291) corresponding to the front view (0-degree view) of the comparative example and the color point (0.304, 0.291) corresponding to the front view (0-degree view) of this embodiment almost overlap. By adjusting the brightness of the blue light in this embodiment, the color point (0.232, 0.169) at the 45-degree view of this embodiment is closer to the color point corresponding to the front view compared to the color point (0.199, 0.137) of the comparative example, that is, in the anti-peeking mode of this embodiment, the light intensity ratios of the red, green, and blue lights at the front view and the side view are closer, which helps to reduce the risk of serious color difference at the front view and the side view.

[0083] In summary, the embodiment of the present application can, without reducing the light-receiving effect, maximize the reduction of the risk of serious color difference at the front view and the side view in the anti-peeking mode.

[0084] In addition, according to experiments, while keeping the driving voltage (5 V) of the first dimming box 20 unchanged, within the range of 5 V to 6.5 V, gradually increasing the driving voltage of the second dimming box 30, the color point coordinates at the 45° view in the anti-peeking view gradually approach the color point coordinates at the 0-degree view in the anti-peeking mode.

[0085] In one embodiment, the amplitude of the first driving voltage is the optimal driving voltage amplitude, and the amplitude of the second driving voltage is a non-optimal driving voltage amplitude. Such a setting can avoid the reduction or excessive reduction of the light-receiving effect of the display device, which affects the anti-peeping effect, and can also improve the color difference situation in the front view and side view.

[0086] In another embodiment, the amplitude of the first driving voltage is a non-optimal driving voltage amplitude, and the amplitude of the second driving voltage is a non-optimal driving voltage amplitude. Such a setting can maximize the improvement of the color difference risk in the front view and side view.

[0087] In one embodiment, the display device 100 further includes an anti-peeping film 60, and the anti-peeping film 60 is disposed between any two of the backlight module 10, the first polarizer 51, the first light modulation box 20, the second polarizer 52, the second light modulation box 30, the third polarizer 42, the liquid crystal panel 41, and the fourth polarizer 43.

[0088] The anti-peeping film 60 is set such that the reflectivity of the anti-peeping film 60 is positively correlated with the incident angle of the light.

[0089] Among them, when the anti-peeping film 60 is disposed between the third polarizer 42 and the second light modulation box 30, the anti-peeping film 60 has the best effect of improving large-angle light leakage. When the anti-peeping film 60 is disposed between the first polarizer 51 and the backlight module 10, the brightness of the display device 100 is the largest, and the effect of improving large-angle light leakage will be reduced.

[0090] Optionally, please refer to Figure 9 , the anti-peeping film 60 includes a plurality of stacked light-transmitting films 61, and the refractive indices of any two adjacent light-transmitting films 61 are different.

[0091] Among them, the thickness of the light-transmitting film 61 is about 100 nanometers, such as 100 nanometers. The total thickness of the anti-peeping film 60 is between 20 micrometers and 300 micrometers, and can be, for example, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 150 micrometers, 200 micrometers, 250 micrometers, or 300 micrometers, etc.

[0092] It should be understood that the incident light will undergo interference reflection after entering the interface inside the film, so that the reflectivity is positively correlated with the incident angle, that is, the transmittance of the light incident at the front view angle is high and the reflectivity is low, and the transmittance of the light incident at a large angle (α>50°) is low and the reflectivity is high.

[0093] After the display device 100 enables the anti-peeping function, the principle of reducing the brightness / front view brightness ratio difference between the small angle (25° to 50°) and the large angle (α > 50°) in the anti-peeping angle direction is as follows: First, the light emitted from the front view angle of the backlight module 10 passes through the front anti-peeping film 60 and reaches the first polarizer 51. Most of the light emitted from the side view angle in the large angle direction (α > 50°) is reflected back to the backlight module 10, converted into front view light through reflection, and then emitted again to reach the first polarizer 51; in the sharing mode, the first and second dimming boxes 20 and 30 in the ECB mode do not modulate the light from the front view angle and the horizontal side view angle, and the light normally passes through the third polarizer 42 and reaches the liquid crystal panel 41. Through the control of a series of pixel points of the liquid crystal panel 41, various colors are mixed; when in the anti-peeping mode, the first and second dimming boxes 20 and 30 in the ECB mode still have no modulation effect on the front view light. The front view light passes through the third polarizer 42 and reaches the liquid crystal panel 41. Through the control of a series of pixel points of the liquid crystal panel 41, various colors are mixed. At the same time, by controlling the tilt state of the liquid crystal in the first and second dimming boxes 20 and 30, the light from the horizontal side view angle is modulated, and the light cannot pass through the third polarizer 42 and reach the inside of the liquid crystal panel 41. When viewed from the side view angle on the side of the third polarizer 42 away from the liquid crystal panel 41, the liquid crystal panel 41 appears black, realizing narrow-angle anti-peeping display. By adjusting the tilt state of the liquid crystal in the liquid crystal cell, the anti-peeping display device can be switched between wide and narrow viewing angles, realizing switchable anti-peeping display.

[0094] In this another embodiment, compared with only adjusting the driving voltages of the first dimming box 20 and the second dimming box 30, this embodiment can also adjust the thickness of the liquid crystal and the refractive index difference Δn.

[0095] Optionally, the thickness of the first liquid crystal layer 22 is different from the thickness of the second liquid crystal layer 32, the refractive index difference Δn of the first liquid crystal layer 22 is different from the refractive index difference Δn of the second liquid crystal layer 32, and the first driving voltage applied to the first dimming box 20 is different from the second driving voltage applied to the second dimming box 30.

[0096] Since different liquid crystals have different refractive index differences Δn, by adjusting different liquid crystals, the light output brightness of the corresponding color light can be adjusted.

[0097] By adjusting the liquid crystal thickness, the liquid crystal refractive index difference Δn, and the driving voltage, the degree of color difference between the front view angle and the side view angle in the anti-peeping mode can be better improved.

[0098] Optionally, the thickness of the first liquid crystal layer 22 is greater than the thickness of the second liquid crystal layer 32, and the refractive index difference Δn of the first liquid crystal layer 22 is less than the refractive index difference Δn of the second liquid crystal layer 32.

[0099] Alternatively, the thickness of the first liquid crystal layer 22 is less than the thickness of the second liquid crystal layer 32, and the refractive index difference Δn of the first liquid crystal layer 22 is greater than the refractive index difference Δn of the second liquid crystal layer 32.

[0100] Among them, the high liquid crystal refractive index difference Δn corresponds to the low liquid crystal layer thickness, which not only maintains a high light transmittance, but also can better reduce the cell thickness and thin the display device 100. The low liquid crystal refractive index difference Δn corresponds to the high liquid crystal layer thickness, which not only maintains a high light transmittance, but also reduces costs. By adopting the method of different liquid crystal refractive index differences Δn corresponding to different liquid crystal layer thicknesses for the first dimming cell 20 and the second dimming cell 30, different light bands can be adjusted in a larger range, and the color difference between the front view angle and the side view angle in the anti-peeking mode can be improved more flexibly.

[0101] Optionally, the thicknesses of both the first liquid crystal layer 22 and the second liquid crystal layer 32 are between 2 microns and 10 microns, and the refractive index differences Δn of both the first liquid crystal layer 22 and the second liquid crystal layer 32 are between 0.1 and 0.26.

[0102] For example, the thicknesses of the first liquid crystal layer 22 and the second liquid crystal layer 32 can each be 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, or 10 microns, etc.

[0103] Optionally, the refractive index differences Δn of both the first liquid crystal layer 22 and the second liquid crystal layer 32 can each be between 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, or 0.26, etc.

[0104] The first driving voltage and the second driving voltage can be further adjusted according to the actual situation to improve the color difference between the front view angle and the side view angle in the anti-peeking mode.

[0105] Optionally, in some embodiments, it can also be that the thickness of the first liquid crystal layer 22 is different from the thickness of the second liquid crystal layer 32, the refractive index difference Δn of the first liquid crystal layer 22 is different from the refractive index difference Δn of the second liquid crystal layer 32, and the first driving voltage applied to the first dimming cell 20 is the same as the second driving voltage applied to the second dimming cell 30.

[0106] Optionally, please refer to Figure 10 , in some embodiments, the display device 100 may further include a third dimming cell 70, and the third dimming cell 70 is disposed between the first dimming cell 20 and the liquid crystal display module 40. The color coordinate offset between the color coordinates at the 45° side view angle in the anti-peeking mode and the color coordinates at the front view angle in the anti-peeking mode is less than 0.1869.

[0107] If among the light rays emitted by the first light-dimming box 20, the deviation ratio of the light intensity of blue light is the largest, that of red light is the second largest, and that of green light is the smallest; then the second light-dimming box 30 is used to reduce the light intensity ratio of blue light, and the third light-dimming box 70 is used to reduce the light intensity ratio of red light. If among the light rays emitted by the first light-dimming box 20, the deviation ratio of the light intensity of red light is the largest, that of blue light is the second largest, and that of green light is the smallest; then the second light-dimming box 30 is used to reduce the light intensity ratio of red light, and the third light-dimming box 70 is used to reduce the light intensity ratio of blue light.

[0108] That is to say, in the embodiment of the present application, by stacking multiple light-dimming boxes and adjusting the box thickness and driving voltage of the second light-dimming box 30 and the third light-dimming box 70 according to the light-emitting characteristics of the first light-dimming box 20, while ensuring that the emitted light has a narrow viewing angle, the problem of serious imbalance in the light intensity ratio of the red, green, and blue light bands is better improved, so that the color coordinates at a 45-degree viewing angle in the anti-peeping mode are closer to the color coordinates at a 0-degree viewing angle in the anti-peeping mode, reducing the color difference between side viewing and front viewing, and further optimizing the anti-peeping effect of the side viewing display screen in the anti-peeping mode.

[0109] Optionally, the third light-dimming box 70 and the first light-dimming box 20 are light-dimming boxes of the same mode, for example, they can both be of the ECB mode or the VA mode.

[0110] Optionally, the third light-dimming box 70 includes a fifth substrate 71, a third liquid crystal layer 72, and a sixth substrate 73 which are sequentially stacked. The fifth substrate 71 is arranged on the side close to the backlight module 10. The third light-dimming box 70 further includes a fifth driving electrode 74, a fifth alignment film 75, a sixth driving electrode 76, and a sixth alignment film 77. The fifth driving electrode 74 is arranged on the side of the fifth substrate 71 close to the third liquid crystal layer 72, and the fifth alignment film 75 is arranged on the side of the fifth driving electrode 74 close to the third liquid crystal layer 72. The sixth driving electrode 76 is arranged on the side of the sixth substrate 73 close to the third liquid crystal layer 72, and the sixth alignment film 77 is arranged on the side of the sixth driving electrode 76 close to the third liquid crystal layer 72.

[0111] Optionally, the refractive index difference Δn of the first liquid crystal layer 22, the refractive index difference Δn of the second liquid crystal layer 32, and the refractive index difference Δn of the third liquid crystal layer 72 of the third light-dimming box 70 are different from each other.

[0112] The thickness of the first liquid crystal layer 22, the thickness of the second liquid crystal layer 32, and the thickness of the third liquid crystal layer 72 of the third light-dimming box 70 are different from each other.

[0113] The first driving voltage applied to the first light-dimming box 20, the second driving voltage applied to the second light-dimming box 30, and the third driving voltage applied to the third light-dimming box 70 are different from each other.

[0114] Of course, in some embodiments, the liquid crystal layer thickness and the refractive index difference Δn of two of the first dimming box 20, the second dimming box 30, and the third dimming box 70 may be the same, or the driving voltages of two of the first dimming box 20, the second dimming box 30, and the third dimming box 70 may be the same.

[0115] It can be understood that the display device 100 may further include more dimming boxes to better improve the problem of serious imbalance in the light intensity ratio of the red, green, and blue light bands and reduce the color difference between the side view and the front view.

[0116] The embodiment of the present application provides a display device, which has a narrow viewing angle anti-peeping mode and a wide viewing angle sharing mode. The display device includes a backlight module, a first dimming box, a second dimming box, and a liquid crystal display module. The first dimming box is disposed on the light-emitting side of the backlight module; the second dimming box is disposed on the light-emitting side of the first dimming box; the liquid crystal display module is disposed on the light-emitting side of the second dimming box; in the side viewing angle of the anti-peeping mode, the second dimming box is used to reduce the color light with the highest brightness emitted by the first dimming box. Among them, in the side viewing angle of the anti-peeping mode, the embodiment of the present application adjusts the second dimming box to reduce the brightest color light emitted by the first dimming box, reduces the gap in the ratio of the red, green, and blue light, and thus improves the phenomenon of color difference between the side viewing angle and the front viewing angle of the display device in the anti-peeping mode.

[0117] The above has introduced in detail a display device provided by the embodiment of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A display device having a narrow viewing angle anti-peeping mode and a wide viewing angle sharing mode, characterized in that: The display device comprises: Backlight module; A first dimming box, which is arranged on the light-emitting side of the backlight module; A second dimming box, the second dimming box is arranged on the light output side of the first dimming box; A liquid crystal display module, which is arranged on the light-emitting side of the second dimming box; In the CIE 1931 chromaticity coordinate system, the color coordinate offset between the color coordinate at a 45° side viewing angle of the anti-peeping mode and the color coordinate at a front viewing angle of the anti-peeping mode is less than 0.1869; The first dimming box comprises a first substrate, a first liquid crystal layer and a second substrate stacked in sequence, the first substrate is arranged at a side close to the backlight module, the second dimming box comprises a third substrate, a second liquid crystal layer and a fourth substrate stacked in sequence, the third substrate is arranged at a side close to the first dimming box; In the anti-peeping mode, a first driving voltage connected to the first dimming box is different from a second driving voltage connected to the second dimming box, so that the first dimming box and the second dimming box adjust different visible light bands.

2. The display device according to claim 1, characterized in that The first substrate is arranged on a side close to the backlight module, the thickness of the first liquid crystal layer is equal to the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is the same as the refractive index difference Δn of the second liquid crystal layer.

3. The display device according to claim 2, characterized in that: The first driving voltage and the second driving voltage are AC voltages, the thickness of the first liquid crystal layer and the second liquid crystal layer are between 4 microns and 8 microns, the amplitude of the first driving voltage is between 3.5 volts and 5.5 volts, the amplitude of the second driving voltage is between 4 volts and 7 volts, and the frequencies of the first driving voltage and the second driving voltage are both between 40 Hz and 120 Hz.

4. The display device according to claim 1, characterized in that The thickness of the first liquid crystal layer is different from the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is different from the refractive index difference Δn of the second liquid crystal layer.

5. The display device according to claim 4, characterized in that: The thickness of the first liquid crystal layer is greater than the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is less than the refractive index difference Δn of the second liquid crystal layer; or The thickness of the first liquid crystal layer is smaller than the thickness of the second liquid crystal layer, and the refractive index difference Δn of the first liquid crystal layer is larger than the refractive index difference Δn of the second liquid crystal layer.

6. The display device according to claim 5, characterized in that: The thickness of the first liquid crystal layer and the thickness of the second liquid crystal layer are both between 2 micrometers and 10 micrometers, and the refractive index difference Δn of the first liquid crystal layer and the refractive index difference Δn of the second liquid crystal layer are both between 0.1 and 0.

26.

7. The display device according to any one of claims 2 to 6, characterized in that: The amplitude of the first driving voltage is an optimal driving voltage amplitude, and the amplitude of the second driving voltage is a non-optimal driving voltage amplitude.

8. The display device according to any one of claims 2 to 6, characterized in that: The amplitude of the first driving voltage is a non-optimal driving voltage amplitude, and the amplitude of the second driving voltage is a non-optimal driving voltage amplitude.

9. The display device according to any one of claims 1 to 6, characterized in that: The display device further includes a first polarizer, a second polarizer and an anti-peep film, the liquid crystal display module includes a liquid crystal panel, a third polarizer and a fourth polarizer, the fourth polarizer is arranged on a side of the liquid crystal panel away from the backlight module, the third polarizer is arranged on a side of the liquid crystal panel close to the backlight module, the second polarizer is arranged between the first dimming box and the second dimming box, and the first polarizer is arranged on a side of the first dimming box close to the backlight module; The privacy film is disposed between any two of the backlight module, the first polarizer, the first dimming box, the second polarizer, the second dimming box, the third polarizer, the liquid crystal panel and the fourth polarizer; The privacy film is configured such that a reflectivity of the privacy film is positively correlated with an incident angle of light.

10. The display device according to claim 9, characterized in that: The anti-peep film comprises a plurality of light-transmitting films stacked together, and any two adjacent layers of the light-transmitting films have different refractive indices.

11. The display device according to any one of claims 1 to 6, characterized in that: The display device also includes a third dimming box, which is arranged between the first dimming box and the liquid crystal display module, and the color coordinate offset between the color coordinates at a 45° side viewing angle of the anti-peeping mode and the color coordinates at a front viewing angle of the anti-peeping mode is less than 0.1869.

Images