Privacy film and display device

Abstract

The present application discloses an anti-peep film and a display device, wherein the anti-peep film comprises: at least two polarizers; a liquid crystal dimming layer, wherein the liquid crystal dimming layer is disposed between two adjacent polarizers; wherein the optical axes of at least two of the polarizers are parallel, and in a first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane of the polarizer is an acute angle. In the present application, by setting the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane of the polarizer to an acute angle in the first mode, the effective long axis of the liquid crystal molecules in the liquid crystal dimming layer and the direction of polarized light in the side-view direction have an angle, thereby making the light in the side-view direction of the anti-peep film darker, thereby achieving anti-peeping, while in non-first modes, the brightness of the light in all directions of the anti-peep film is similar, thereby achieving sharing.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an anti-peep film and a display device. Background Art

[0002] With the increasing popularity and application of display devices, such as smartphones, laptops, and tablets, users have become concerned about others being able to read sensitive or private information. In public places, users are increasingly concerned about personal information privacy, and the concept of anti-peeping display devices is gaining popularity. A common anti-peeping device is a layer of privacy film applied to the outer surface of the display device, which blackens the left and right sides and makes them invisible. However, this privacy protection method is not switchable, and because the privacy film uses an opaque structure, it reduces light utilization efficiency. Summary of the Invention

[0003] The present application provides an anti-peeping film and a display device to achieve switching between an anti-peeping mode and a sharing mode.

[0004] The present application provides a privacy film, which includes:

[0005] At least two polarizers;

[0006] A liquid crystal dimming layer is provided between two adjacent polarizers;

[0007] The optical axes of at least two of the polarizers are parallel to each other. In the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizers are located is an acute angle.

[0008] Optionally, in some embodiments of the present application, in the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizer is located is greater than or equal to 50 degrees and less than or equal to 70 degrees.

[0009] Optionally, in some embodiments of the present application, the plane where the polarizer is located is the xy plane composed of the x-axis and the y-axis, and the normal direction of the polarizer is the z-axis direction perpendicular to the xy plane. In the first mode, the long axis of the liquid crystal molecules in the liquid crystal dimming layer is in the yz plane and the angle with the y-axis is β, and the light in the side view direction of the anti-peep film is in the xz plane and the angle with the z-axis is θ, wherein β=arctan((1+tanθ) / (2 1 / 2 tanθ)), the value of β is greater than or equal to 50 degrees and less than or equal to 70 degrees.

[0010] Optionally, in some embodiments of the present application, in the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizer is located is 62.63 degrees.

[0011] Optionally, in some embodiments of the present application, the number of the polarizers is at least three, and the number of the liquid crystal dimming layers is at least two. In the first mode, the long axes of the liquid crystal molecules in at least two layers of the liquid crystal dimming layers are parallel to the orthographic projections of the polarizers.

[0012] Optionally, in some embodiments of the present application, the liquid crystal dimming layer includes at least a first liquid crystal dimming layer and a second liquid crystal dimming layer. In the first mode, the long axis of the liquid crystal molecules in the first liquid crystal dimming layer and the orthographic projection of the liquid crystal molecules in the second liquid crystal dimming layer on the polarizer have an angle.

[0013] Optionally, in some embodiments of the present application, in the first mode, the long axis of the liquid crystal molecules in the first liquid crystal dimming layer is perpendicular to the orthographic projection of the liquid crystal molecules in the second liquid crystal dimming layer on the polarizer.

[0014] Optionally, in some embodiments of the present application, the liquid crystal dimming layer further includes:

[0015] The third liquid crystal dimming layer, in the first mode, the long axis of the liquid crystal molecules in the first liquid crystal dimming layer is parallel to the orthographic projection of the liquid crystal molecules in the third liquid crystal dimming layer on the polarizer.

[0016] Optionally, in some embodiments of the present application, the liquid crystal dimming layer further includes:

[0017] The fourth liquid crystal dimming layer, in the first mode, the long axis of the liquid crystal molecules in the second liquid crystal dimming layer is parallel to the orthographic projection of the liquid crystal molecules in the fourth liquid crystal dimming layer on the polarizer.

[0018] Optionally, in some embodiments of the present application, the thickness of the liquid crystal dimming layer ranges from 2 microns to 7 microns.

[0019] Optionally, in some embodiments of the present application, in the second mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the normal of the polarizer is φ, φ is greater than or equal to 87 degrees and less than or equal to 90 degrees, or φ is greater than or equal to zero degrees and less than or equal to 5 degrees.

[0020] Optionally, in some embodiments of the present application, the privacy film further includes:

[0021] a first electrode;

[0022] a second electrode, the second electrode being arranged opposite to the first electrode;

[0023] The liquid crystal dimming layer is disposed between the first electrode and the second electrode; wherein,

[0024] The polarizer is arranged on a side of the first electrode and the second electrode away from the liquid crystal dimming layer.

[0025] Optionally, in some embodiments of the present application, the privacy film further includes:

[0026] a first alignment layer, the first alignment layer being provided on a side of the first electrode close to the liquid crystal dimming layer;

[0027] The second alignment layer is provided on a side of the second electrode close to the liquid crystal dimming layer.

[0028] Accordingly, the present application also provides a display device, comprising:

[0029] The privacy film described above;

[0030] A display panel is provided on a side of the polarizer of the privacy film away from the liquid crystal dimming layer.

[0031] Optionally, in some embodiments of the present application, the display device further includes:

[0032] A backlight source, the backlight source comprising a collimated light source;

[0033] A light guide plate is provided on a side of the privacy film away from the display panel, and the collimated light source is provided on a side surface of the light guide plate.

[0034] The present application provides an anti-peep film and a display device, wherein the anti-peep film includes: at least two polarizers; a liquid crystal dimming layer, wherein the liquid crystal dimming layer is disposed between two adjacent polarizers; wherein the optical axes of at least two of the polarizers are parallel, and in a first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane of the polarizer is an acute angle. In the present application, by setting the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane of the polarizer to an acute angle in the first mode, the effective long axis of the liquid crystal molecules in the liquid crystal dimming layer and the direction of polarized light in the side-viewing direction have an angle, thereby making the light in the side-viewing direction of the anti-peep film darker, thereby achieving privacy protection, while in non-first modes, the brightness of the light in all directions of the anti-peep film is similar, thereby achieving sharing; and the liquid crystal dimming layer is light-transmissive, which is conducive to improving light utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 This is a schematic diagram of the first structure of the privacy film provided by this application;

[0037] Figure 2 This is a schematic diagram of the structure of light and liquid crystal molecules in the side view direction of the privacy film of the present application in the first mode;

[0038] Figure 3 A model diagram of light and liquid crystal molecules in the side view direction of the privacy film of the present application in the first mode;

[0039] Figure 4 A schematic diagram of the display device of the present application;

[0040] Figure 5 2 is a schematic diagram of the second structure of the privacy film provided by the present application;

[0041] Figure 6 2 is a third structural schematic diagram of the privacy film provided by the present application;

[0042] Figure 7 2 is a fourth structural schematic diagram of the privacy film provided by the present application;

[0043] Figure 8 This is the fifth structural schematic diagram of the privacy film provided by this application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0045] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0046] The present application provides an anti-peep film and a display device, which are described in detail below. It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments of the present application.

[0047] See also Figure 1 , Figure 1 This is a first structural diagram of the privacy film 100 provided by the present application. The embodiment of the present application also provides a privacy film 100, which includes: at least two polarizers 10 and a liquid crystal dimming layer 20;

[0048] The liquid crystal dimming layer 20 is disposed between two adjacent polarizers 10; the optical axes of at least two polarizers 10 are parallel. In a first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane of the polarizers 10 is acute. The first mode is also an anti-peeping mode.

[0049] This application utilizes the birefringence of the liquid crystal molecules 21 to control the brightness of light in the side-view direction of the privacy film 100, thereby achieving a privacy-preventing effect in the side-view direction of the privacy film 100. Specifically, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane of the polarizer 10 is set to an acute angle, so that in the side-view direction, the effective long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 has an angle with the direction of polarized light. As a result, the light F1 in the side-view direction of the privacy film 100 is darker, thereby achieving privacy protection. In the non-first mode, the brightness of light in all directions of the privacy film 100 is similar, and can be shared. In addition, the liquid crystal dimming layer is light-transmissive, which helps improve light utilization efficiency.

[0050] The principle is as follows: the half-wave plate has special optical properties. A layer of polarizer 10 with optical axis parallel to the upper and lower sides of the half-wave plate is added. When the incident direction of the linearly polarized light passing through the polarizer 10 on the lower side is at an angle of 45 degrees or -45 degrees with the long axis of the half-wave plate, the polarization direction F2 of the linearly polarized light passing through the half-wave plate is rotated by 90 degrees and is absorbed by the polarizer 10 on the upper side. Therefore, the linearly polarized light passing through the polarizer 10 on the lower side cannot pass through the polarizer 10 on the upper side.

[0051] The birefringence and dielectric properties of the liquid crystal molecules 21 can form a half-wave plate while also having switching properties. The following two conditions must be met to form a half-wave plate using the liquid crystal dimming layer 20 in the side view direction of the privacy film 100: Condition 1: the phase delay difference of the liquid crystal dimming layer 20 in the side view direction of the privacy film 100 is equal to the phase delay difference of the half-wave plate; Condition 2: the angle between the effective long axis of the liquid crystal molecules 21 and the vibration direction of the linearly polarized light in the side view direction of the privacy film 100 is 45 degrees. For specific implementation methods, please refer to Figure 2 and Figure 3 , Figure 2 Schematic diagram of the structure of the light F1 and the liquid crystal molecules in the side view direction of the privacy film 100 of the present application in the first mode. Figure 3 This is a model diagram of the light F1 and the liquid crystal molecules in the side-view direction of the privacy film 100 of the present application in the first mode. For the birefringence characteristics of the liquid crystal molecules 21, ne is the refractive index of the liquid crystal molecules 21 in the long axis direction, and no is the refractive index of the liquid crystal molecules 21 in the short axis direction. The polarizer is located in the xy plane, and the normal direction of the polarizer is the z-axis direction perpendicular to the xy plane. The liquid crystal molecules 21 are in the yz plane and the angle between the long axis of the liquid crystal molecules 21 and the y-axis is β. The light F1 in the side-view direction of the privacy film 100 is located in the xz plane and the angle between the long axis and the z-axis is θ. The angle between the light F1 in the side-view direction of the privacy film 100 and the long axis of the liquid crystal molecules 21 is α. At this time, the liquid crystal molecules 21 have a refractive index no and an effective refractive index ne' of the effective long axis, wherein ne'=ne×no÷(ne 2 cos 2 α+no 2 sin 2 α) 1 / 2 , and the direction vector of the effective long axis is located in a plane perpendicular to the light F1 in the side view direction of the privacy film 100. At this time, the angle between the direction vector of the effective long axis and the polarization direction F2 of the linearly polarized light is γ. As mentioned above, when the value of the angle γ is equal to 45 degrees, the angle β between the long axis of the liquid crystal molecule 21 and the y-axis satisfies β = arctan((1 + tanθ) / (2 1 / 2tanθ)), the angle α between the light F1 in the side view direction of the privacy film 100 and the long axis of the liquid crystal molecule 21 satisfies α=arccos(cosθ×sin(arctan((1+tanθ) / (2 1 / 2 tanθ)))). At this time, the phase retardation difference of the liquid crystal dimming layer 20 is 2π(ne'-no)d' / λ, where d' is the distance linearly polarized light travels in the liquid crystal dimming layer 20, ne' and no are the refractive index parameters of the liquid crystal molecules 21, and λ is the wavelength. Once the liquid crystal molecules 21 are selected, the refractive index parameters of the liquid crystal molecules 21 cannot be changed. d' is related to the thickness d of the liquid crystal dimming layer 20, d'=d / cosθ. Therefore, by changing d', the phase retardation difference of the liquid crystal dimming layer 20 of 2π(ne'-no)d' / λ is achieved. When it is equal to (2k+1)π, where k=0, ±1, ±2, etc., the liquid crystal dimming layer 20 now acts as a half-wave plate. That is, the light passing through the polarizer 10 on the lower side of the liquid crystal dimming layer 20 forms linearly polarized light and then enters the liquid crystal dimming layer 20. In the side viewing direction of the anti-peep film 100, the polarization direction F2 of the linear polarized light is exactly rotated 90 degrees after passing through the liquid crystal dimming layer 20, and is thus absorbed by the polarizer 10 located on the upper side of the liquid crystal dimming layer 20. Therefore, the light passing through the polarizer 10 located on the lower side of the liquid crystal dimming layer 20 in the side viewing direction of the anti-peep film 100 cannot pass through the polarizer 10 located on the upper side of the liquid crystal dimming layer 20, thereby achieving privacy protection in the side viewing direction of the anti-peep film 100.

[0052] In summary, the pointing vector of the effective major axis lies in a plane perpendicular to the light F1 when viewed from the side of the privacy film 100. This means that the angle between the pointing vector of the effective major axis and the polarization direction F2 of the linearly polarized light varies at different angles when viewed from the side of the privacy film 100. Therefore, the brightness of the light seen from different angles when viewed from the side of the privacy film 100 varies, achieving varying degrees of privacy protection. Furthermore, when the angle between the pointing vector of the effective major axis and the polarization direction F2 of the linearly polarized light is 45 degrees, light that passes through the polarizer 10 below the liquid crystal dimming layer 20 when viewed from the side of the privacy film 100 cannot pass through the polarizer 10 above the liquid crystal dimming layer 20, achieving complete privacy protection when viewed from the side of the privacy film 100.

[0053] It should be emphasized that the angle in the side-view direction is a known value. The following uses the brightness of the privacy film 100 at an angle of 30 degrees in the side-view direction to illustrate the privacy protection effect of the privacy film 100. When the light F1 in the side-view direction of the privacy film 100 is located in the xz plane and the angle θ with the z-axis is 30 degrees, the angle β between the long axis of the liquid crystal molecule 21 and the y-axis is 62.63 degrees. At this time, the angle γ between the pointing vector of the effective long axis and the polarization direction F2 of the linearly polarized light is 45 degrees. The thickness d of the liquid crystal dimming layer 20 is adjusted so that 2π(ne'-no)d' / λ is equal to (2k+1)π, k=0, ±1, ±2..., at this time, in the side-view direction of the privacy film 100, Specifically, when the angle between the pointing vector of the effective long axis of the liquid crystal dimming layer 20 and the polarization direction F2 of the linearly polarized light is 45 degrees, the polarization direction F2 of the linearly polarized light is rotated 90 degrees so that the angle between the pointing vector of the effective long axis and the polarization direction F2 of the linearly polarized light is 45 degrees. When the side view direction of the anti-peep film 100 is such that the light passing through the polarizer 10 located on the lower side of the liquid crystal dimming layer 20 cannot pass through the polarizer 10 located on the upper side of the liquid crystal dimming layer 20, the anti-peep effect is optimal. The angle β is not limited to 62.63 degrees, that is, the angle γ is not limited to 45 degrees; for example, when the angle β is greater than 62.63 degrees, the angle γ will be greater than 45 degrees, and when the angle β is less than 62.63 degrees, the angle γ will be less than 45 degrees. For example, when the angle γ is 50 degrees, after passing through the liquid crystal dimming layer 20, the polarization direction of the polarized light will be deflected by 100 degrees. At this time, the angle between the polarization direction of the polarized light and the absorption axis of the polarizer 10 is 10 degrees, which will cause most of the light to be absorbed by the polarizer 10 located on the upper side of the liquid crystal dimming layer 20, and a small amount of light will pass through, but the brightness in the side viewing direction will still be greatly reduced.

[0054] As can be seen above, to achieve optimal privacy protection, angle γ must be maintained at 45 degrees. Changes in angle θ will also cause changes in angle β. When light F1, viewed from the side of the privacy film 100, lies in the xz plane and has an angle θ of 30 degrees with the z-axis, in order to achieve an angle γ of 45 degrees between the pointing vector of the effective major axis and the polarization direction F2 of the linearly polarized light, thus achieving optimal privacy protection, angle β must be increased to 62.63 degrees.

[0055] Furthermore, there are no restrictions on the thickness d of the liquid crystal layer. The thickness d can vary significantly depending on the type of liquid crystal used (the liquid crystal parameters are the refractive index parameters of the liquid crystal molecules 21) and the angle β between the long axis of the liquid crystal molecules 21 and the y-axis. Furthermore, the angle β between the long axis of the liquid crystal molecules 21 and the y-axis is not limited and can be achieved through various methods, such as electric fields, alignment materials, and microstructures.

[0056] The following is a description of the experimental test data:

[0057] Based on the above-described structure of the privacy film 100, by adjusting the angle β between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 of the privacy film 100 and the y-axis to a set value, and using a light source to provide light on one side of the privacy film 100, the privacy film 100 can actually achieve the following privacy protection effects. The following table shows a comparison of brightness at multiple viewing angles when using only a light source, and a comparison of brightness at multiple viewing angles when using a light source and the privacy film 100 together;

[0058] Viewing Angle 75° 60° 45° 30° 15° 0° -15° -30° -45° -60° -75° Brightness of the light source 8.56％ 9.49％ 15.41％ 38.60％ 76.12％ 100.00％ 73.93％ 38.60％ 15.12％ 9.83％ 8.64％ Light source and brightness of privacy film 100 2.15％ 2.22％ 1.43％ 12.36％ 58.47％ 100.00％ 57.36％ 12.31％ 1.58％ 2.43％ 1.82％

[0059] As can be seen from the table, when the light source and the anti-peep film 100 are used in combination, the brightness seen at the side viewing direction of the anti-peep film 100 is smaller than the brightness seen at the front viewing direction of the anti-peep film 100. Therefore, it can be seen that the anti-peep film 100 of the present application has a good anti-peep effect in the side viewing direction.

[0060] Specifically, in this embodiment, the privacy film 100 includes: two polarizers 10 and a liquid crystal dimming layer 20;

[0061] The liquid crystal dimming layer 20 is disposed between the two polarizers 10 .

[0062] In some embodiments, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane where the polarizer 10 is located is greater than or equal to 50 degrees and less than or equal to 70 degrees. Furthermore, the plane where the polarizer is located is the xy plane composed of the x-axis and the y-axis, and the normal direction of the polarizer is the z-axis direction perpendicular to the xy plane. In the first mode, the long axis of the liquid crystal molecules in the liquid crystal dimming layer is in the yz plane and the angle with the y-axis is β, and the light in the side viewing direction of the anti-peep film is in the xz plane and the angle with the z-axis is θ, where β=arctan((1+tanθ) / (2 1 / 2 tanθ)), the value of β is greater than or equal to 50 degrees and less than or equal to 70 degrees.

[0063] That is, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane where the polarizer 10 is located is the same as the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the y-axis, and the angle β between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the y-axis is greater than or equal to 50 degrees and less than or equal to 70 degrees. Correspondingly, the anti-peep angle in the side viewing direction of the anti-peep film is between 55 degrees and 20 degrees. Specifically, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the y-axis is 50 degrees, and the light F1 in the side-viewing direction of the privacy film 100 is located in the xz plane and has an angle θ of 55 degrees with the z-axis. At this time, the angle γ between the pointing vector of the effective long axis and the polarization direction F2 of the linearly polarized light is 45 degrees, thus achieving the best privacy protection effect. In the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the y-axis is 70 degrees, and the light F1 in the side-viewing direction of the privacy film 100 is located in the xz plane and has an angle θ with the z-axis of 20 degrees. At this time, the angle γ between the pointing vector of the effective long axis and the polarization direction F2 of the linearly polarized light is 45 degrees, thus achieving the best privacy protection effect. In particular, in the first mode, when the light in the side-viewing direction of the privacy film is located in the xz plane and has an angle θ with the z-axis, the brightness of the privacy film in the side-viewing direction is less than 13%.

[0064] The side-view privacy protection angle commonly used in existing common display products is between 45 and 60 degrees. However, considering the position of in-vehicle display products in relation to the driver's seat or passenger seat, the side-view privacy protection angle of in-vehicle display products needs to be around 30 degrees. Therefore, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane of the polarizer needs to be 50 to 70 degrees. In this case, the light in the side-view direction of the privacy film is located in the xz plane and the angle with the z-axis is between 55 and 20 degrees. In other words, the side-view privacy protection angle of the privacy film is between 55 and 20 degrees, which is more suitable for the use scenario of in-vehicle display products. Therefore, in the first mode, the angle β between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the y-axis is set to be greater than or equal to 50 degrees and less than or equal to 70 degrees, which is more conducive to privacy protection.

[0065] Furthermore, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane of the polarizer 10 is 62.63 degrees. At this time, when the light F1 in the side view direction of the privacy film 100 is located in the xz plane and the angle θ with the z-axis is 30 degrees, the angle γ between the pointing vector of the effective long axis and the polarization direction F2 of the linearly polarized light can be made to be 45 degrees, thus achieving the best privacy protection effect. In the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane of the polarizer 10 is greater than or equal to 50 degrees and less than or equal to 62.63 degrees, and the privacy protection angle in the side view direction of the privacy film is between 30 degrees and 20 degrees. In the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane where the polarizer 10 is located is greater than or equal to 62.63 degrees and less than or equal to 70 degrees, then the privacy protection angle in the side viewing direction of the privacy protection film is between 55 degrees and 30 degrees.

[0066] In some embodiments, the thickness of the liquid crystal dimming layer 20 ranges from 2 microns to 7 microns. Excessively thick liquid crystal dimming layer 20 not only results in excessive liquid crystal gravity but also increases the difficulty of the manufacturing process. Both of these situations can easily lead to uneven display. Therefore, the thickness of the liquid crystal dimming layer 20 should not be too thick. Furthermore, the thickness of the liquid crystal dimming layer 20 ranges from 3 microns to 5 microns. Setting the thickness of the liquid crystal dimming layer 20 between 2 microns and 7 microns, or even between 3 microns and 5 microns, not only provides a better anti-peeping effect, but also reduces the difficulty of the manufacturing process and avoids the occurrence of uneven display.

[0067] In some embodiments, in the second mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the normal to the polarizer 10 is φ, and φ is greater than or equal to 87 degrees and less than or equal to 90 degrees, or φ is greater than or equal to zero degrees and less than or equal to 5 degrees. The second mode is also known as the sharing mode. For optimal results, in the second mode, the long axis of the liquid crystal molecules 21 in the dimming liquid crystal layer is arranged perpendicular to or parallel to the normal to the polarizer 10, that is, the angle between the long axis of the liquid crystal molecules 21 in the dimming liquid crystal layer and the normal to the polarizer 10 is 90 degrees or zero degrees. The liquid crystal molecules 21 are either negative or positive. Specifically, in the second mode, when the liquid crystal molecules 21 are positive, the value of φ is greater than or equal to 87 degrees and less than or equal to 90 degrees; when the liquid crystal molecules 21 are negative, the value of φ is greater than or equal to zero degrees and less than or equal to 5 degrees.

[0068] In some embodiments, the privacy film 100 further includes:

[0069] a first electrode 31;

[0070] a second electrode 32 , the second electrode 32 being arranged opposite to the first electrode 31 ;

[0071] The liquid crystal dimming layer 20 is disposed between the first electrode 31 and the second electrode 32; wherein,

[0072] The polarizer 10 is disposed on a side of the first electrode 31 and the second electrode 32 away from the liquid crystal dimming layer 20. The first electrode 31 and the second electrode 32 can be whole electrodes or multiple electrode plates arranged at intervals.

[0073] In some embodiments, the privacy film 100 further includes:

[0074] a first alignment layer 51 , which is provided on a side of the first electrode 31 close to the liquid crystal dimming layer 20 ;

[0075] The second alignment layer 52 is provided on a side of the second electrode 32 close to the liquid crystal dimming layer 20 .

[0076] The liquid crystal molecules 21 in the liquid crystal dimming layer 20 are pre-aligned by the first alignment layer 51 and the second alignment layer 52 , wherein the first alignment layer 51 and the second alignment layer 52 comprise polyimide alignment films.

[0077] In some embodiments, the privacy film 100 further includes:

[0078] a first substrate 41 , the first substrate 41 being disposed on a side of the first electrode 31 away from the liquid crystal dimming layer 20 ;

[0079] The second substrate 42 is disposed on a side of the second electrode 32 away from the liquid crystal dimming layer 20 . Specifically, the polarizer 10 is disposed on a side of the first substrate 41 and the second substrate 42 away from the liquid crystal dimming layer 20 .

[0080] The first electrode 31 and the second electrode 32 are supported by providing a first substrate 41 and a second substrate 42 , wherein the materials of the first substrate 41 and the second substrate 42 can be glass, polyester resin, transparent polyimide, ultra-thin glass and the like.

[0081] Please refer to Figure 4 , Figure 4 Schematic diagram of a display device 200 of the present application. The present application also provides a display device 200 comprising: the privacy film 100 described above and a display panel 60 , wherein the display panel 60 is disposed on a side of the polarizer 10 away from the liquid crystal dimming layer 20 .

[0082] The principle of solving the problem of the display device 200 is similar to that of the aforementioned privacy film 100. Therefore, the implementation and beneficial effects of the display device 200 can refer to the description of the aforementioned privacy film 100, and the repeated parts will not be repeated here.

[0083] The display device 200 further includes a display polarizer 70 , which is disposed on a side of the display panel 60 away from the liquid crystal dimming layer 20 . The optical axis of the display polarizer 70 is perpendicular to the optical axis of the polarizer 10 .

[0084] Please refer to the following table, which is a brightness comparison table of the display device 200 at multiple viewing angles.

[0085] Viewing Angle 75° 60° 45° 30° 15° 0° -15° -30° -45° -60° -75° The brightness of the display device 200 0.03％ 0.09％ 0.24％ 1.06％ 22.83％ 100.00％ 22.72％ 0.93％ 0.22％ 0.07％ 0.02％

[0086] From the brightness comparison of the display device 200 at multiple viewing angles, it can be seen that the display device 200 using the anti-peep film 100 of the present application has a very good anti-peep effect in the side viewing direction.

[0087] The display device 200 further includes a backlight source 80, which is disposed on a side of the privacy film 100 away from the display panel 60. The backlight source 80 is a collimated light source 82 or a divergent light source 81. The collimated light source 82 can emit collimated light and can be implemented using methods such as an inverse prism backlight, a collimating film, and a collimating lens. The collimated light source 82 provides a better display effect and helps reduce light loss during transmission.

[0088] The backlight source 80 includes a collimated light source 82 and a divergent light source 81, and the display device 200 also includes: a first light guide plate 91 and a second light guide plate 92, the first light guide plate 91 and the second light guide plate 92 are stacked in sequence on the side of the anti-peep film 100 away from the display panel 60, the divergent light source 81 is arranged on the side of the first light guide plate 91, and the collimated light source 82 is arranged on the side of the second light guide plate 92.

[0089] The backlight source 80 can emit either divergent or collimated light. The first light guide plate 91 can emit divergent light, while the second light guide plate 92 can emit collimated light. In privacy mode, the first light guide plate 91 is active, meaning the incident light on the privacy film 100 is divergent light. In sharing mode, the second light guide plate 92 is active, meaning the incident light on the privacy film 100 is collimated light. It's important to note that there's no restriction on only one light guide plate operating in privacy mode or sharing mode; both the first and second light guide plates 91 and 92 can operate simultaneously, depending on actual needs.

[0090] In some embodiments, in the first mode, the angle between the long axis of the liquid crystal molecules 21 in the liquid crystal dimming layer 20 and the plane where the polarizer 10 is located is greater than or equal to 50 degrees and less than or equal to 70 degrees. Furthermore, the plane where the polarizer is located is the xy plane composed of the x-axis and the y-axis, and the normal direction of the polarizer is the z-axis direction perpendicular to the xy plane. In the first mode, the long axis of the liquid crystal molecules in the liquid crystal dimming layer is in the yz plane and the angle with the y-axis is β, and the light in the side viewing direction of the anti-peep film is in the xz plane and the angle with the z-axis is θ, wherein β=arctan((1+tanθ) / (2 1 / 2 tanθ), where β is greater than or equal to 50 degrees and less than or equal to 70 degrees. Specifically, in the first mode, when light in the side view direction of the privacy film is located in the xz plane and has an angle θ with the z-axis, the brightness of the display device 200 in the side view direction is less than 1.2%.

[0091] See also Figure 5 , Figure 5 This is a second structural diagram of the privacy film 100 provided by the present application. Figure 1 The difference between the privacy film 100 provided in the present application is that the liquid crystal dimming layer 20 includes a polymer network 22 and liquid crystal molecules 21 distributed in the polymer network 22. When the liquid crystal molecules 21 are pre-aligned, an electric field can be used to tilt the liquid crystal molecules 21 to a set angle, and then the polymer in the dimming liquid crystal layer can be solidified by ultraviolet light or other means to form a polymer network 22. After the electric field is removed, the polymer network 22 will maintain the liquid crystal molecules 21 tilted at the set angle. In the above case, an optimal setting angle can be selected according to actual needs, and then the polymer network 22 can be used to maintain the liquid crystal molecules 21 tilted at the set angle. Specifically, the setting angle can be: the angle between the long axis of the liquid crystal molecules 21 in the dimming liquid crystal layer and the plane where the polarizer 10 is located is 50 degrees to 70 degrees. At this time, the privacy film 100 is in the first mode.

[0092] See also Figure 6 , Figure 6 This is a third structural diagram of the privacy film 100 provided in this application. Since the liquid crystal dimming layer 20 is provided between two adjacent polarizers 10, when the number of polarizers 10 is at least three, the number of liquid crystal dimming layers 20 is at least two. In actual use, since a single layer of liquid crystal dimming layer 20 cannot achieve the theoretical privacy protection effect, a multi-layer liquid crystal dimming layer 20 is provided to enhance the privacy protection effect, thereby making the privacy film 100 close to the theoretical privacy protection effect. Figure 1The difference between the privacy film 100 provided in the present application is that the number of the polarizers 10 is at least three, and correspondingly, the number of the liquid crystal dimming layers 20 is at least two. In the first mode, the long axes of the liquid crystal molecules 21 in at least two layers of the liquid crystal dimming layers 20 are parallel to the orthographic projections of the polarizer 10.

[0093] Specifically, there are three polarizers 10 , and correspondingly, there are two liquid crystal dimming layers 20 . In the first mode, the long axes of the liquid crystal molecules 21 in the two liquid crystal dimming layers 20 are parallel to the orthographic projections of the polarizer 10 .

[0094] See also Figure 7 , Figure 7 This is a fourth structural diagram of the privacy film 100 provided by the present application. Figure 1 The difference between the privacy film 100 provided in the present application is that the liquid crystal dimming layer 20 includes at least a first liquid crystal dimming layer 201 and a second liquid crystal dimming layer 202. In the first mode, the long axis of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 and the orthographic projection of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 on the polarizer 10 have an angle.

[0095] When, in the first mode, the liquid crystal molecules 21 in the liquid crystal dimming layer 20 of the privacy film 100 lie in the yz plane and the angle β between the long axis of the liquid crystal molecules 21 and the y-axis is β, the privacy film 100 exhibits a privacy protection effect in the side view direction on both sides of the y-axis. Therefore, in the first mode, when the liquid crystal molecules 21 in the liquid crystal dimming layer 20 of the privacy film 100 have only one tilt direction, privacy protection can only be achieved in two directions. To achieve a wider privacy protection angle, it is necessary to set the liquid crystal molecules 21 in the liquid crystal dimming layer 20 of the privacy film 100 to tilt in multiple directions in the first mode.

[0096] Therefore, in this embodiment, the long axis of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 has an angle on the orthographic projection of the polarizer 10 and the long axis of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 has an angle on the orthographic projection of the polarizer 10, so a larger privacy protection angle can be obtained. For example, when in the first mode, the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 of the privacy film 100 are in the yz plane and the angle between the long axis of the liquid crystal molecules 21 and the y axis is β, then the first liquid crystal dimming layer 201 of the privacy film 100 has an anti-peeping effect in the side viewing direction on both sides of the y axis; and the second liquid crystal dimming layer of the privacy film 100 has an anti-peeping effect in the side viewing direction on both sides of the y axis. The liquid crystal molecules 21 in the crystal dimming layer 202 are not in the yz plane. At this time, the long axis of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 and the long axis of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 on the polarizer 10 have an angle. Then, the anti-peep angle of the second liquid crystal dimming layer 202 of the anti-peep film 100 is different from the anti-peep angle of the first liquid crystal dimming layer 201 of the anti-peep film 100. Therefore, the anti-peep angle of the anti-peep film 100 is the combination of the anti-peep angle of the second liquid crystal dimming layer 202 and the anti-peep angle of the first liquid crystal dimming layer 201, and a larger anti-peep angle can be obtained.

[0097] Furthermore, in the first mode, the long axes of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 are perpendicular to the orthographic projection of the polarizer 10 and the long axes of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202. In this case, when, in the first mode, the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 of the privacy film 100 are in the yz plane and the angle between the long axes of the liquid crystal molecules 21 and the y-axis is β, the first liquid crystal dimming layer 201 of the privacy film 100 has an anti-peeping effect in the side-viewing direction on both sides of the y-axis; and the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 of the privacy film 100 are in the xz plane and the angle between the long axes of the liquid crystal molecules 21 and the x-axis is β, the second liquid crystal dimming layer 202 of the privacy film 100 has an anti-peeping effect in the side-viewing direction on both sides of the x-axis. The privacy protection angle of the privacy film 100 is the combination of the privacy protection angle of the second liquid crystal dimming layer 202 and the privacy protection angle of the first liquid crystal dimming layer 201. Therefore, the privacy film 100 can achieve privacy protection in four directions: forward viewing direction, rearward viewing direction, left viewing direction and right viewing direction.

[0098] See also Figure 8 , Figure 8 This is a fifth structural diagram of the privacy film 100 provided by this application. Figure 7 The difference between the privacy film 100 provided in this application is that the liquid crystal dimming layer 20 further includes:

[0099] Regarding the third liquid crystal dimming layer 203, in the first mode, the long axes of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 are parallel to the orthographic projection of the liquid crystal molecules 21 in the third liquid crystal dimming layer 203 on the polarizer 10. In actual use, since a single-layer liquid crystal dimming layer 20 cannot achieve the theoretical anti-peeping effect, multiple liquid crystal dimming layers 20 are provided to enhance the anti-peeping effect, thereby making the anti-peeping film 100 approach the theoretical anti-peeping effect. Therefore, the first liquid crystal dimming layer 201 and the third liquid crystal dimming layer 203 are provided, and in the first mode, the long axes of the liquid crystal molecules 21 in the first liquid crystal dimming layer 201 and the third liquid crystal dimming layer 203 are tilted in the same direction, thereby enhancing the anti-peeping effect of the anti-peeping film 100 in a certain direction.

[0100] Furthermore, in some embodiments, the liquid crystal dimming layer 20 further includes:

[0101] In the fourth liquid crystal dimming layer 204, in the first mode, the long axes of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 are parallel to the orthographic projection of the polarizer 10 and the long axes of the liquid crystal molecules 21 in the fourth liquid crystal dimming layer 204 are parallel to the orthographic projection of the polarizer 10. By providing the second liquid crystal dimming layer 202 and the fourth liquid crystal dimming layer 204, and in the first mode, the long axes of the liquid crystal molecules 21 in the second liquid crystal dimming layer 202 and the fourth liquid crystal dimming layer 204 are tilted in the same direction, the privacy protection effect of the privacy film 100 in a certain direction can be enhanced.

[0102] In addition, the first liquid crystal dimming layer 201 and the second liquid crystal dimming layer 202 may be disposed adjacent to each other or not. In this embodiment, the first liquid crystal dimming layer 201 and the second liquid crystal dimming layer 202 are two adjacent liquid crystal dimming layers 20 .

[0103] The above is a detailed introduction to an anti-peep film and a display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and 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 may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A privacy film, characterized in that: include: At least two polarizers; A liquid crystal dimming layer is provided between two adjacent polarizers; The optical axes of at least two of the polarizers are parallel to each other, and in the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizers are located is an acute angle; The plane where the polarizer is located is the xy plane composed of the x-axis and the y-axis. The normal direction of the polarizer is the z-axis direction perpendicular to the xy plane. In the first mode, the long axis of the liquid crystal molecules in the liquid crystal dimming layer is in the yz plane and the angle between it and the y-axis is β. The light in the side view direction of the privacy film is in the xz plane and the angle between it and the z-axis is θ, where β=arctan((1+tanθ) / (2 1 / 2 tanθ)), the value of β is greater than or equal to 50 degrees and less than or equal to 70 degrees; In the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizer is located is the same as the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the y-axis.

2. The privacy film according to claim 1, wherein: In the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizer is located is greater than or equal to 50 degrees and less than or equal to 70 degrees.

3. The privacy film according to claim 2, characterized in that: In the first mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the plane where the polarizer is located is 62.63 degrees.

4. The privacy film according to claim 1, wherein: There are at least three polarizers, and at least two liquid crystal dimming layers. In the first mode, the long axes of liquid crystal molecules in at least two liquid crystal dimming layers are parallel to the orthographic projections of the polarizers.

5. The privacy film according to claim 1, wherein: The liquid crystal dimming layer includes at least a first liquid crystal dimming layer and a second liquid crystal dimming layer. In the first mode, the long axis of the liquid crystal molecules in the first liquid crystal dimming layer and the orthographic projection of the liquid crystal molecules in the second liquid crystal dimming layer on the polarizer have an angle.

6. The privacy film according to claim 5, characterized in that: In the first mode, the orthographic projection of the long axes of the liquid crystal molecules in the first liquid crystal dimming layer on the polarizer is perpendicular to the orthographic projection of the long axes of the liquid crystal molecules in the second liquid crystal dimming layer on the polarizer.

7. The privacy film according to claim 6, characterized in that: The liquid crystal dimming layer further includes: The third liquid crystal dimming layer, in the first mode, the long axis of the liquid crystal molecules in the first liquid crystal dimming layer is parallel to the orthographic projection of the liquid crystal molecules in the third liquid crystal dimming layer on the polarizer.

8. The privacy film according to claim 6, characterized in that: The liquid crystal dimming layer further includes: The fourth liquid crystal dimming layer, in the first mode, the long axis of the liquid crystal molecules in the second liquid crystal dimming layer is parallel to the orthographic projection of the liquid crystal molecules in the fourth liquid crystal dimming layer on the polarizer.

9. The privacy film according to claim 1, wherein: The thickness of the liquid crystal dimming layer ranges from 2 microns to 7 microns.

10. The privacy film according to claim 1, wherein: In the second mode, the angle between the long axis of the liquid crystal molecules in the liquid crystal dimming layer and the normal of the polarizer is φ, which is greater than or equal to 87 degrees and less than or equal to 90 degrees, or greater than or equal to zero degrees and less than or equal to 5 degrees.

11. The privacy film according to claim 1, wherein: The privacy film further comprises: a first electrode; a second electrode, the second electrode being arranged opposite to the first electrode; The liquid crystal dimming layer is disposed between the first electrode and the second electrode; wherein, The polarizer is arranged on a side of the first electrode and the second electrode away from the liquid crystal dimming layer.

12. The privacy film according to claim 11, characterized in that: The privacy film further comprises: a first alignment layer, the first alignment layer being provided on a side of the first electrode close to the liquid crystal dimming layer; The second alignment layer is provided on a side of the second electrode close to the liquid crystal dimming layer.

13. A display device, characterized in that: include: The privacy film according to any one of claims 1 to 12; A display panel is provided on a side of the polarizer of the privacy film away from the liquid crystal dimming layer.

14. The display device according to claim 13, wherein: The display device further includes: A backlight source, the backlight source comprising a collimated light source; A light guide plate is provided on a side of the privacy film away from the display panel, and the collimated light source is provided on a side surface of the light guide plate.

Images