A view angle controllable backlight module and liquid crystal display

Abstract

The application discloses a kind of view angle controllable backlight module and liquid crystal display, the backlight module includes: light guide plate;Diffusion film, diffusion film is set above light guide plate;Prism brightening film, prism brightening film is set above diffusion film;Polarization brightening film, polarization brightening film is set above prism brightening film;Optical coating glass, optical coating glass is set above polarization brightening film, for reflecting specific direction large-angle light;Liquid crystal screen, liquid crystal screen is set above optical coating glass.The application is inserted between the DBEF film and liquid crystal screen of traditional backlight module by special optical coating glass, make large-angle light in a specific direction reflect back backlight system, that is, with similar and the function of anti-peep film to large-angle stray light suppression.Due to the light that is reflected is reused in backlight system, its light efficiency is higher than anti-peep film;Will not be interfered with display pixel and produce moire, and display effect is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a backlight module with controllable viewing angle and a liquid crystal display. BACKGROUND

[0002] In the cockpit of an automobile or an airplane, the light with large angle emitted by the liquid crystal display can be reflected to the eyes of the driver or the pilot through the cockpit glass, especially in the scene of dark ambient light at night, the stray light will interfere with the driver or the pilot, which is not conducive to the safety of driving or flying. In order to suppress the stray light of the display, an anti-peep film is generally attached to the surface of the backlight or the liquid crystal screen to suppress the light with large angle. The principle of the anti-peep film is shown in Figure 1 The core layer of the anti-peep film is a louvered microstructure layer, the microstructure has good absorption effect on light, and can block the light with large angle and only allow the light near the normal line to pass through. The louver is a one-dimensional periodic structure, so it has good anti-peep effect in one direction.

[0003] The anti-peep film can effectively suppress the stray light in one direction, but due to the absorption effect on light, it has poor transmittance (~70%) and low light efficiency. In addition, when attached to the surface of the screen, the louver microstructure easily interferes with the display pixels, generates moire fringes, and reduces the display quality. SUMMARY

[0004] In the embodiment, a backlight module with controllable viewing angle and a liquid crystal display are provided to solve the problem of interference with display pixels, generation of moire fringes and reduction of display quality in the related art during use.

[0005] In a first aspect, the embodiment of the present application provides a backlight module with controllable viewing angle, which comprises:

[0006] a light guide plate;

[0007] a diffusion film, which is arranged above the light guide plate;

[0008] a prism brightness enhancement film, which is arranged above the diffusion film;

[0009] a polarized brightness enhancement film, which is arranged above the prism brightness enhancement film;

[0010] optical coated glass, which is arranged above the polarized brightness enhancement film and is used for reflecting the light with large angle in a specific direction;

[0011] a liquid crystal screen, which is arranged above the optical coated glass.

[0012] In an optional embodiment, the substrate of the optical coated glass is soda-lime glass or borosilicate glass.

[0013] In an alternative embodiment, the optical coating glass is coated with optical films of SiO2, TiO2 and MgF2 in turn.

[0014] In an alternative embodiment, the optical film has 10 layers, and each layer has a thickness ranging from 10.6nm to 183.7nm.

[0015] In an alternative embodiment, the optical film has the following thicknesses of the layers:

[0016] Layer 1: SiO2, thickness 82.7nm;

[0017] Layer 2: TiO2, thickness 10.6nm;

[0018] Layer 3: SiO2, thickness 46.3nm;

[0019] Layer 4: TiO2, thickness 34.5nm;

[0020] Layer 5: SiO2, thickness 12.9nm;

[0021] Layer 6: TiO2, thickness 178.6nm;

[0022] Layer 7: MgF2, thickness 11.4nm;

[0023] Layer 8: TiO2, thickness 27.4nm;

[0024] Layer 9: MgF2, thickness 183.7nm;

[0025] Layer 10: TiO2, thickness 36.8nm.

[0026] In an alternative embodiment, the optical coating glass has a reflectivity of s-wave that increases with the increase of the incident angle, and the reflectivity is 65% when the incident angle is 60°, and the reflectivity is 90% when the incident angle is 80°.

[0027] In an alternative embodiment, the optical coating glass is prepared by a magnetron sputtering method, and the sputtering pressure is 0.3-4.6Pa, the substrate temperature is 200-500℃, and the deposition rate is 0.2-100nm / min.

[0028] In an alternative embodiment, the optical coating glass is arranged close to the polarized brightening film.

[0029] Compared with the prior art, the backlight module with controllable viewing angle has the following advantages:

[0030] The application inserts special optical coated glass between the DBEF film and the liquid crystal screen of a traditional backlight module, so that the large-angle light in a specific direction is reflected back to the backlight system, that is, the function of suppressing large-angle stray light similar to that of a privacy film is achieved. The base material of the coated glass is soda-lime glass or borosilicate glass, and the surface has optical thin films of three materials, SiO2, TiO2 and MgF2, alternately. The minimum thickness of the thin film layer is 10.6 nm, the maximum thickness is 183.7 nm, and the typical number of film layers is 10. In the application, the reflected light is reused in the backlight system, so the light efficiency is higher than that of a privacy film. The optical coating is a flat film layer, which does not interfere with the display pixels to produce moire, and the display effect is good.

[0031] In a second aspect, the application provides a liquid crystal display comprising the view angle controllable backlight module of the first aspect.

[0032] In an optional embodiment, the liquid crystal display is used in the cockpit of a car or an airplane to suppress the interference of large-angle stray light on the driver or the pilot.

[0033] Compared with the prior art, the liquid crystal display of the application has the same advantages as the view angle controllable backlight module of the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0035] Figure 1 It is a schematic diagram of the principle of the privacy film in the prior art.

[0036] Figure 2 It is a schematic diagram of the architecture of the view angle controllable backlight module in the embodiment of the application.

[0037] Figure 3 It is a schematic diagram of p wave and s wave in the embodiment of the application.

[0038] Figure 4 It is a transmission and reflection spectrum diagram of the coated glass in the embodiment of the application. DETAILED DESCRIPTION

[0039] In order to more clearly understand the purpose, technical solutions and advantages of the application, the application will be described and explained in the following with reference to the drawings and embodiments.

[0040] Unless otherwise defined, technical terms and scientific terms used in the present application shall have the same meaning as those commonly understood by one of ordinary skill in the art to which the present application pertains. The terms "one", "a", "an", "the", "these", and similar terms in the present application do not mean "only one" or "exactly one", but are understood to mean "one or more". The terms "including", "containing", "having", and any variations thereof in the present application are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or device that includes a list of steps or modules (units) is not limited to the listed steps or modules (units), but can include other steps or modules (units) not listed or can include other steps or modules (units) inherent to the process, method, product, or device. The terms "connected", "connected to", "coupled", and similar terms in the present application do not mean physical or mechanical connection, but can include electrical connection, whether direct or indirect. The term "multiple" in the present application means two or more. The term "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean that A exists alone, A and B exist together, and B exists alone. Generally, the character " / " means that the objects before and after are "or" relationship. The terms "first", "second", "third", and the like in the present application are only used to distinguish similar objects, and do not mean a specific order of the objects.

[0041] A view angle controllable backlight module is provided in the embodiments of the present application, Figure 2 is a schematic diagram of the architecture of the view angle controllable backlight module of the present application, as Figure 2 shown, the view angle controllable backlight module comprises:

[0042] a light guide plate 101;

[0043] a diffusion film 102, the diffusion film 102 is arranged above the light guide plate 101;

[0044] a prism brightening film 103, the prism brightening film 103 is arranged above the diffusion film 102;

[0045] a polarization brightening film 104, the polarization brightening film 104 is arranged above the prism brightening film 103;

[0046] an optical coated glass 105, the optical coated glass 105 is arranged above the polarization brightening film 104, and is used to reflect large-angle light rays in a specific direction;

[0047] a liquid crystal screen 106, the liquid crystal screen 106 is arranged above the optical coated glass 105.

[0048] It should be noted that the general liquid crystal backlight module includes LED light bar 107, light guide plate 101, diffusion film 102, prism brightening film 103, polarization brightening film 104 (DBEF) and liquid crystal screen 106 (LCD). The light emitted by the LED light bar 107 is diffused into a uniform surface light source by the light guide plate 101, the diffusion film 102 and the prism brightening film 103, and then converted into linearly polarized light by the DBEF polarization multiplexing effect. The polarization transmission axis direction of the DBEF is consistent with the polarization transmission axis direction of the lower polarizing plate of the LCD.

[0049] To realize the function of controllable viewing angle, the general liquid crystal backlight module is improved by inserting a special optical coated glass 105 between the polarization brightening film 104 and the liquid crystal screen 106. It should be noted that the coated surface of the optical coated glass 105 is arranged close to the polarization brightening film 104.

[0050] The backlight module is based on the traditional structure of the light guide plate 101, the diffusion film 102, the prism brightening film 103 and the polarization brightening film 104, and the optical coated glass 105 is inserted between the polarization brightening film 104 (DBEF) and the liquid crystal screen 106. The coated glass has high reflectivity for large-angle incident light (>60°) in a specific direction (such as s wave), so that it is reflected back to the backlight system for reuse, while small-angle light (such as p wave) can still normally transmit.

[0051] Specifically, the coated glass has a selective transmission effect for linearly polarized light incident in different directions. The backlight light is converted into linearly polarized light after passing through the DBEF, and the polarization direction is consistent with the polarization transmission axis direction of the DBEF. Since there are various light rays in the backlight, the light rays incident on the coated glass, such as Figure 3 as shown in the figure, are defined as p wave when the polarization direction is in the incident plane, and the short line in the figure represents the electric field direction; and are defined as s wave when the polarization direction is perpendicular to the incident plane, and the dot in the figure represents the electric field direction; the light rays in other directions can be equivalent to the vector superposition of p wave and s wave.

[0052] The substrate of the optical coated glass 105 is nanocalcium glass or borosilicate glass. It should be noted that nanocalcium glass has low cost and good optical uniformity; borosilicate glass has high temperature resistance and strong thermal stability, and is suitable for harsh environments (such as automobiles and aviation).

[0053] In this embodiment, the surface of the optical coated glass 105 is coated with optical thin films of three materials, SiO2, TiO2 and MgF2, which are alternately arranged.

[0054] In this embodiment, the number of layers of the optical thin film is 10, and the thickness of each film layer ranges from 10.6 nm to 183.7 nm.

[0055] In this embodiment, the optical film layer on the surface of the coated glass is shown in Table 1:

[0056] Table 1: Coated glass film layer material and layer thickness

[0057]

[0058] The reflectivity of the optical coated glass 105 to s-wave increases with the increase of the incident angle. When the incident angle is 60°, the reflectivity is about 65%, and when the incident angle is 80°, the reflectivity is about 90%.

[0059] The coated glass in Table 1 is simulated optically, and the simulation results are shown in Table 2. Figure 4 For the transmittance spectrum in the visible light band (400nm-700nm), the p-wave incident angle is in the range of 0° to 80°, and the transmittance is between 70% and 100%. With the increase of the incident angle, the transmittance relatively increases. The s-wave incident angle is in the range of 0° to 80°, and with the increase of the incident angle, the transmittance rapidly decreases. When the incident angle is 60°, the transmittance is about 35%, and when the incident angle is 80°, the transmittance is about 10%. Since high-absorption materials are not used in the glass substrate and the optical film system material, the untransmitted light is reflected. The p-wave incident angle is in the range of 0° to 80°, and the reflectivity is between 0% and 30%. The s-wave incident angle is in the range of 0° to 80°, and with the increase of the incident angle, the reflectivity rapidly increases. When the incident angle is 60°, the reflectivity is about 65%, and when the incident angle is 80°, the reflectivity is about 90%. The reflectivity can fluctuate within ±5%.

[0060] According to the simulation results above, for the p-wave, the coated glass is not sensitive to the incident angle of the light, and for the s-wave, the coated glass has a good reflection effect on the large-angle light with an angle greater than 60°, i.e. the large-angle light is suppressed. Compared with the anti-peep film, since the reflected light is reused in the backlight system, the light efficiency is high, and the power consumption of the display module is low. The optical coating is a flat film layer, which does not interfere with the display pixels to generate moire, and the display effect is good.

[0061] In this embodiment, the optical coated glass 105 is prepared by a magnetron sputtering method. The sputtering gas pressure is 0.3-4.6 Pa, the substrate temperature is 200-500℃, and the deposition rate is 0.2-100 nm / min.

[0062] The film layer on the glass surface is prepared by a magnetron sputtering method. The process parameters of the sputtering gas pressure, the substrate temperature and the deposition rate are shown in Table 2:

[0063] Table 2: Process parameters for preparing the optical film layer by a magnetron sputtering method

[0064]

[0065] In summary, the embodiment provides a view angle controllable backlight module. By inserting a special optical coated glass 105 between the DBEF film and the liquid crystal screen 106 of the traditional backlight module, the large-angle light in a specific direction is reflected back to the backlight system, which has the function of suppressing large-angle stray light similar to the privacy film. The base material of the coated glass is soda-lime glass or borosilicate glass, and the surface has alternating optical thin films of SiO2, TiO2 and MgF2. The minimum thickness of the thin film layer is 10.6 nm, and the maximum thickness is 183.7 nm. The typical number of film layers is 10. In the present application, the reflected light is reused in the backlight system, and the light efficiency is higher than that of the privacy film. The optical coating is a flat film layer, which does not interfere with the display pixels and does not produce moire patterns, and the display effect is good.

[0066] The embodiment also provides a liquid crystal display comprising the view angle controllable backlight module.

[0067] In the embodiment, the liquid crystal display is used in the cockpit of an automobile or an airplane to suppress the interference of large-angle stray light on the driver or the pilot.

[0068] The view angle controllable backlight module is integrated with the liquid crystal screen to realize directional light control through the coated glass. The display avoids reflection interference in the automobile / aviation scene while maintaining high brightness and low power consumption. In the cockpit environment, the coated glass suppresses the display stray light reflected by the windshield. The driving safety is improved, and it is especially suitable for night or strong light environment.

[0069] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A view angle controllable backlight module, characterized in that, The view angle controllable backlight module comprises: a light guide plate (101); a diffusion film (102) arranged above the light guide plate (101); a prism brightness enhancement film (103) arranged above the diffusion film (102); a polarized brightness enhancement film (104) arranged above the prism brightness enhancement film (103); an optical coated glass (105) arranged above the polarized brightness enhancement film (104) for reflecting s-polarized light with large incident angle; a liquid crystal screen (106) arranged above the optical coated glass (105).

2. The view angle controllable backlight module according to claim 1, wherein, The substrate of the optical coated glass (105) is soda lime glass or borosilicate glass.

3. The view angle controllable backlight module according to claim 1 or 2, characterized in that, The optical coated glass (105) is coated with optical thin films of SiO2, TiO2 and MgF2 in turn.

4. The view angle control backlight module according to claim 3, characterized in that, The optical thin films have 10 layers, and each layer has a thickness ranging from 10.6 nm to 183.7 nm.

5. The view angle control backlight module according to claim 4, wherein, The thickness of each layer of the optical thin films is as follows: 1st layer: SiO2, 82.7 nm; 2nd layer: TiO2, 10.6 nm; 3rd layer: SiO2, 46.3 nm; 4th layer: TiO2, 34.5 nm; 5th layer: SiO2, 12.9 nm; 6th layer: TiO2, 178.6 nm; 7th layer: MgF2, 11.4 nm; 8th layer: TiO2, 27.4 nm; 9th layer: MgF2, 183.7 nm; 10th layer: TiO2, 36.8 nm.

6. The view angle control backlight module according to claim 1, wherein, The reflectivity of the optical coated glass (105) to s-wave increases with the increase of the incident angle, and when the incident angle is 60°, the reflectivity is 65%, and when the incident angle is 80°, the reflectivity is 90%.

7. The view angle control backlight module according to claim 1, wherein, The optical coated glass (105) is prepared by a magnetron sputtering method, and the sputtering pressure is 0.3-4.6 Pa, the substrate temperature is 200-500 ℃, and the deposition rate is 0.2-100 nm / min.

8. The view angle control backlight module according to claim 1, wherein, The coated surface of the optical coated glass (105) is arranged close to the polarized brightness enhancement film (104).

9. A liquid crystal display, characterized by comprising: The view angle controllable backlight module according to any one of claims 1-8.

10. The liquid crystal display of claim 9, wherein, The liquid crystal display is used in the cockpit of an automobile or an airplane to suppress the interference of large-angle stray light on the driver or the pilot.

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