Anti-peeping film with asymmetric microstructure

Abstract

According to the anti-peeping film with the asymmetric structure, one side of a light absorption unit structure is linear, the other side of the light absorption unit structure is a 5-order or 4-order curvilinear function, the slope of the maximum characteristic of the curvilinear function is gradually reduced when the maximum characteristic of the curvilinear function is close to the top position, and therefore the function that the single side is more anti-peeping is achieved; in addition, the peep-proof film product is high in process feasibility, and industrial large-scale production is easy to achieve.

Description

Technical Field

[0001] The invention relates to the field of optical films, in particular to an asymmetric microstructured anti-peeping film and a preparation method thereof in the field of anti-peeping display technology. Background Art

[0002] With the development of display information technology, the following problems are common in various display fields: with the widespread use of smartphones, computers, etc., consumers often face the risk of leakage of personal privacy and business secrets; in display fields such as in-vehicle HUD, drivers are easily disturbed by the reflected light of the display. For this reason, it is usually necessary to use anti-peep film products with ultra-fine louver structures to solve the above problems. The anti-peep film structure can effectively control the light output angle of the display, so that it can only be seen from the front and invisible from the side in display fields such as mobile phones and computers; in the field of in-vehicle displays, it can directly prevent the light emitted from the display from entering areas such as the windshield, eliminate reflected imaging, and avoid interference.

[0003] The traditional privacy film structure is described in patent WO2018 / 078493A2, in which the transmission unit and the light absorbing unit are arranged alternately and periodically, the basic structure of the light absorbing unit is a trapezoidal structure, and the ratio H / W of the structural depth H to the transmission unit width W is at least 1 or 1.75 or greater; the wall angle of adjacent trapezoidal light absorbing unit structures is not greater than 6°; the viewing angle is less than or equal to 40°; the refractive index N1 of the transmission unit resin and the refractive index N2 of the light absorbing unit resin are N2-N1=±0.005.

[0004] Patent JP2006343711A provides a field of view angle control sheet and a display device. The field of view angle control sheet can effectively reduce brightness loss and improve the contrast of the image observed by the observer. The field of view angle control sheet is formed by periodically alternating the transmission unit and the light absorption unit. The wedge-shaped structure of the light absorption unit is roughly an isosceles triangle, and the hypotenuse of the wedge-shaped structure of the light absorption unit is a broken line or a curve; the angle between the inclined surface of the wedge-shaped structure of the light absorption unit and the normal line of the light emitting surface is 3°-15°, and the refractive index of the transmission unit material Ny and the refractive index of the light absorption unit wedge-shaped structure material Nx, Ny≧Nx.

[0005] Patent CN218630258U provides an anti-peep film, which can effectively improve the phenomenon that the existing transmission unit and the light-absorbing unit are easy to peel off under weather-resistant conditions. The cross-section of the transmission unit of the anti-peep film is basically a quadrilateral, and the angle between the waist or hypotenuse of the quadrilateral and the vertical line is not higher than 2°. The bevel of the transmission unit has a certain degree of roughness, and the roughness is 0.01μm-0.8μm. The roughness is formed by a random concave-convex structure, a wavy structure, or a repeatedly arranged geometric structure. The refractive index N1 of the transmission unit is 1.46-1.56, and the refractive index N2 of the light-absorbing zone is 1.45-1.55, and the N1-N2 is ≥ 0.005.

[0006] Patent CN117250673A provides an anti-peeping film with an elliptical microstructure for the light-absorbing unit cross-section, presenting a full-curved surface structure arranged periodically. The ratio b / a of the major axis b to the minor axis a of the elliptical microstructure of the light-absorbing unit is 5 - 30, preferably 8, 10, 15, 20, 23, 28.

[0007] However, the single microstructures of existing conventional trapezoidal anti-peeping films are all symmetric structures. In the fields of vehicle-mounted displays and industrial control displays, a completely symmetric optical viewing angle distribution is not required. Instead, an asymmetric structure can shift the optical center normal line to one side, making the viewing angle on the side where light control is needed more convergent and the viewing angle on the side where light control is not needed more divergent.

[0008] Patent CN221993666U provides an asymmetric anti-peeping film, which includes a transparent substrate layer and an anti-peeping layer located on the surface of the substrate layer. The anti-peeping layer includes a plurality of light-blocking parts and a plurality of light-transmitting parts. The light-blocking parts and the light-transmitting parts are alternately arranged to form the anti-peeping layer. The light-transmitting parts form a visible area on the side of the substrate layer. The viewing angle of the visible area is defined as α, and 30° ≤ α < 90°. Define the axis parallel to the thickness direction of the substrate layer as the first axis. The first axis divides the viewing angle α into a first viewing angle α1 and a second viewing angle α2, and α1 > α2. The disadvantage of this asymmetric anti-peeping film is that its so-called asymmetry is the asymmetry of the included angle of the two bottom corners on the left and right. At the same viewing angle, the luminance of the vertical viewing angle will be relatively low; or at the same luminance, the viewing angle is larger and the anti-peeping effect becomes worse.

[0009] Therefore, it is necessary to develop an asymmetric structure to improve and optimize the display screen with a need for an asymmetric optical viewing angle distribution. Summary of the Invention

[0010] Aiming at the problems in the prior art, the present invention provides an asymmetric anti-peeping film. The overall structure of its light-absorbing unit is linear on one side, and its expression is: f(x) = tan(α) * x, where α is the bottom angle of the processing tool, and the range of the angle α is 80 - 89°; the other side is a 5th or 4th-order curve function, and the expression is: f(x) = ax 5 + bx 4 + cx 3 + dx 2 + ex + f; where 0 < a < 1, b < 0, c > 0, d * e * f ≠ 0. When a = 0 and the function is a 4th-order function, then 0 < b < 1, c < 0, d * e * f ≠ 0. The characteristics of this curve function are that most of the bottom is the same as the linear waist, and only a small part near the top angle has a certain curvature.

[0011] The expressions on both sides of the tool with a normal symmetric linear structure, where the bottom corner angle is α and the horizontal coordinate displacement is g. The expression for one side's waist is: f(x) = tan(α) * x; the expression for the other side's waist is: f(x) = tan(180° - α) * (x - g), as Figure 2 .

[0012] For one side of the present invention, the waist expression remains: f(x) = tan(α) * x; but for the other side, the waist expression is: f(x) = ax 5 + bx 4 + cx 3 + dx 2 + ex + f; and its waistline is a 5th - order or 4th - order curve function. The maximum characteristic of this curve function is that its slope gradually decreases when approaching the top position until f(x) > a set height, such as 80μm, 100μm, 120μm, as Figure 3 , Figure 4 .

[0013] Since quadratic and cubic functions cannot accurately fit this curve trend, for this curve function, 0 < a < 1, b < 0, c > 0, d * e * f ≠ 0, or a = 0, 0 < b < 1, c < 0, d * e * f ≠ 0.

[0014] Using function curve generation software, set the tabular values of x and f(x) for the general trend. According to the tabular values, perform regression line fitting (including straight line, hyperbola, natural logarithm, power, exponential, high - order sequence functions), and finally it is found that a 5th - order or 4th - order sequence function can accurately fit the design requirements.

[0015] The present invention first provides an anti - peeping film with an asymmetric structure. The overall structure of its light - absorbing unit is linear on one side, and its expression is: f(x) = tan(α) * x, where α is the bottom corner angle of the processing tool, and the range of the angle α is 80 - 89°; on the other side, it is a 5th - order or 4th - order curve function, and the expression is: f(x) = ax 5 + bx 4 + cx 3 + dx 2 + ex + f;

[0016] where 0 < a < 1, this function is a 5th - order function, b < 0, c > 0, d * e * f ≠ 0,

[0017] or a = 0, this function is a 4th - order function, 0 < b < 1, c < 0, d * e * f ≠ 0;

[0018] When the tool processes the curve function, the x and y series point coordinates with a step distance of 0.1 μm are set according to the characteristics of the curve function. The tool processing equipment processes the tool according to the x and y series coordinates. x and y are the coordinates of the tool, representing the milling stroke and path.

[0019] Furthermore, the angle α is 82°, 84°, 86°, or 88°.

[0020] Furthermore, when the function is a fifth-order function, a>0.001, or 0.1, and a<0.8, or 0.5.

[0021] Furthermore, when the function is a fifth-order function, b>-100, or -15.

[0022] Furthermore, when the function is a 5th order function, c>3, or 700, and c<10 6 , or 10 5 .

[0023] Furthermore, when the function is a fourth-order function, b>0.1, or 0.2, and b<0.9, or 0.8.

[0024] Furthermore, when the function is a 4th order function, c>-100, or -50.

[0025] Furthermore, the tool is milled by ultra-precision CNC milling. x and y are the coordinates of the CNC milling tool, representing the CNC milling stroke and path.

[0026] Furthermore, the function is a fifth-order curve function 1:

[0027] f(x)=0.1019537*x 5 -13.9729399*x 4 +764.368664*x 3 -20864.0303523*x 2 +284218.6784201*x-(1.5461961*10 6 ),(like Figure 5 blue curve)

[0028] Furthermore, the function is a fifth-order curve function 2:

[0029] f(x)=0.0060252*x 5 -0.4607229*x 4 +3.5311811*x 3 +542.2393839*x 2-16709.8044609 * x + 144789.2715965. (As Figure 5 red curve)

[0030] Furthermore, the function is a 4th - order curve function 1:

[0031] f(x) = 0.3030147 * x 4 -34.7157299 * x 3 +1485.8215792 * x 2 -28137.9222807 * x + 198864.1109986, 25 < x < 35. Within the X value range, this 4th - order function highly coincides with the 5th - order function of Example 4.

[0032] Furthermore, the function is a 4th - order curve function 2:

[0033] f(x) = 0.3903576 * x 4 -44.5184641 * x 3 +1897.5470278 * x 2 -35808.923115 * x + 252363.0142044, 25 < x < 35. Within the X value range, this 4th - order function highly coincides with the 5th - order function of Example 5.

[0034] The present invention also provides a preparation method for an asymmetric - structure anti - peeping film, including:

[0035] Step (1), processing tool

[0036] According to the asymmetric - structure characteristics, one side is linear, and its expression is: f(x) = tan(α) * x, where α is the base - angle of the processing tool, and the range of the angle α is 80 - 89°; the other side is a 5 - or 4 - order curve function, and the expression is: f(x) = ax 5 +bx 4 +cx 3 +dx 2 +ex + f;

[0037] where 0 < a < 1, this function is a 5th - order function, b < 0, c > 0, d * e * f ≠ 0,

[0038] or a = 0, this function is a 4th - order function, 0 < b < 1, c < 0, d * e * f ≠ 0;

[0039] Set the x, y series point coordinates with a step - size of 0.1 μm and process the tool;

[0040] Step (2), prepare the mold roller

[0041] preparing a die roll on a copper roll using a cutter;

[0042] Step (3), microstructure transfer

[0043] Using a mold roller, the transmission unit resin material is UV-cured to transfer the microstructure on the mold roller to the surface of the substrate to form a transmission unit structure layer, i.e., a semi-finished material;

[0044] Step (4), preparing a mirror-finished roller

[0045] Use arc knife to cut the surface of copper roller or prepare mirror roller by grinding and polishing;

[0046] Step (5), preparing a privacy film

[0047] The light absorbing unit resin material is filled above the semi-finished transmission unit structure layer by using a mirror roller, and then cured by UV to obtain the finished privacy film.

[0048] Furthermore, in step (3), the resin material of the transmission unit is preferably acrylic resin.

[0049] Furthermore, in step (3), the resin is composed of monomers, oligomers, photoinitiators and additives, and has a refractive index between 1.4 and 1.65.

[0050] Furthermore, in step (3), the UV curing method can be a mercury lamp, LED, etc.

[0051] Furthermore, in step (3), the UV curing energy of the transmission unit resin and the light absorption unit resin is 300-1000 mJ / cm 2 , or 500mJ / cm 2 、600mJ / cm 2 、800mJ / cm 2 .

[0052] Furthermore, in step (4), a circular cutter with an ultra-large curvature radius is used to turn the surface of the copper roller.

[0053] Furthermore, in step (5), the light absorbing unit resin material is formed by mixing acrylic resin and carbon black slurry.

[0054] Furthermore, in step (5), the light absorption unit resin reflectivity is between 1.4 and 1.65.

[0055] Furthermore, in step (5), the UV curing method can be a mercury lamp, LED, etc.

[0056] Furthermore, in step (5), the UV curing energy of the transmission unit resin and the light absorption unit resin is 800-1500 mJ / cm 2, or 900mJ / cm 2 、1000mJ / cm 2 、1200mJ / cm 2 .

[0057] Furthermore, the present invention specifically provides a method and steps for preparing an asymmetric privacy film:

[0058] Step (1), according to the asymmetric structural characteristics, one side is a linear structure; the other side is a curve function of the highest order 5;

[0059] When the tool is processing the curve function, the x and y series point coordinates with a step distance of 0.1 μm need to be set according to the characteristics of the curve function, and the tool processing equipment processes the tool according to the x and y series coordinates;

[0060] The tool is milled by ultra-precision CNC. XY is the coordinate of the CNC milling tool, representing the CNC milling stroke and path;

[0061] Step (2) After the tool processing is completed, a mold roller (such as Figure 6 );

[0062] Step (3) uses a mold roller to transfer the microstructure on the mold roller to the surface of the substrate by UV curing, thereby forming a transmission unit structure layer, i.e., a semi-finished material; wherein the resin material of the transmission unit is preferably acrylic resin. The resin is composed of monomers, oligomers, photoinitiators, and additives. The refractive index of the resin is between 1.4 and 1.65. The UV curing method can be mercury lamp, LED, etc. The UV curing energy of the transmission unit resin and the light absorption unit resin is 300-1000mJ / cm 2 ;

[0063] Step (4) preparing a mirror roller for the light-absorbing unit structure of the privacy film; the mirror roller can be made by turning the copper roller surface with an arc cutter with an ultra-large curvature radius or by grinding and polishing;

[0064] In step (5), a mirror roller is used to fill the light-absorbing unit resin material above the semi-finished transmission unit structural layer, and the finished anti-peep film is obtained by UV curing. The light-absorbing unit resin material is made by mixing acrylic resin and carbon black slurry in a certain proportion. The refractive index of the resin is between 1.4-1.65. UV curing can be carried out by mercury lamp, LED, etc. The UV curing energy of the transmission unit resin and the light-absorbing unit resin is 800-1500mJ / cm 2 ;

[0065] Furthermore, the method for preparing the privacy film provided by the present invention is applicable to the production of sheets and also to the production of coils.

[0066] The present invention also provides an application of the aforementioned privacy film, which is applied to mobile phones, computers, and vehicle-mounted display devices.

[0067] The anti-peep film provided by the present invention has a light absorption unit structure that is linear on one side and a curve function of the highest order of 5 on the other side. The slope of the curve function tends to gradually decrease, thereby achieving a function of better anti-peeping on one side. In addition, the anti-peep film product process is highly feasible and easy to realize industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic diagram of the actual asymmetric anti-peep structure product;

[0069] Figure 2 It is a normal symmetrical and asymmetrical anti-peeping structure (unit: μm);

[0070] Figure 3 This is the structural feature of this patent, where the waistline on one side is a function of the highest order of 5;

[0071] Figure 4 It is the contrast difference between normal structure and curvilinear function structure;

[0072] Figure 5 It is the contrast difference of different 5th order curve functions;

[0073] Figure 6 It is a schematic diagram of the tool processing on the copper roller;

[0074] Figure 7 This is a schematic diagram of a normal symmetrical anti-peeping structure;

[0075] Figure 8 This is a schematic diagram of the asymmetric anti-peeping structure of the patent;

[0076] Fig. 9 is the spatial energy distribution and viewing angle curve of Example 1;

[0077] Fig.10 is the spatial energy distribution and viewing angle curve of Example 2;

[0078] Fig.11 is the spatial energy distribution and viewing angle curve of Example 3;

[0079] Fig.12 It is a comparison of the viewing angle simulation of embodiments 1, 2, and 3;

[0080] Fig.13 This is an actual comparison of the viewing angles of Examples 1 and 3. DETAILED DESCRIPTION

[0081] To better understand the structure of the present invention and the functional features and advantages that can be achieved, the following will combine with the preferred embodiments of the present invention and be described in detail as follows:

[0082] As Figure 5 shown, taking the bottom angle set at 88°, the height at 80 μm, and the length of the bottom of the trapezoid within the closed area at 26 μm as an example.

[0083] The embodiments are respectively:

[0084] 1. Embodiment 1 is a symmetric straight line;

[0085] 2. Embodiment 2 is an asymmetric straight line with an asymmetric angle deviation of 5°;

[0086] 3. Embodiment 3 is an asymmetric straight line with an asymmetric angle deviation of 10°;

[0087] 4. Examples 4, 5, and 6 are three fifth-order function curves respectively.

[0088] Embodiment 1:

[0089] f(x) = tan(88°) * (x - 26), as Figure 2 the blue curve.

[0090] Embodiment 2:

[0091] f(x) = tan(83°) * (x - 26).

[0092] Embodiment 3:

[0093] f(x) = 0.1019537 * x 5 - 13.9729399 * x 4 + 764.368664 * x 3 - 20864.0303523 * x 2 + 284218.6784201 * x - (1.5461961 * 10 6 ), 25 < x < 35, as Figure 5 the blue curve.

[0094] Embodiment 4:

[0095] f(x) = 0.0060252 * x 5 - 0.4607229 * x 4 + 3.5311811 * x 3 + 542.2393839 * x 2 - 16709.8044609 * x + 144789.2715965, 25 < x < 35, as Figure 5 the red curve.

[0096] Example 5:

[0097] f(x) = 0.3030147 * x 4 - 34.7157299 * x 3 + 1485.8215792 * x 2 - 28137.9222807 * x + 198864.1109986, 25 < x < 35. Within the range of X values, this fourth - order function highly coincides with the fifth - order function of Example 4.

[0098] Example 6:

[0099] f(x) = 0.3903576 * x 4 - 44.5184641 * x 3 + 1897.5470278 * x 2 - 35808.923115 * x + 252363.0142044, 25 < x < 35. Within the range of X values, this fourth - order function highly coincides with the fifth - order function of Example 5.

[0100] According to Examples 1, 2, 3, 4, 5, and 6, use 3D software to call the function to draw curves for modeling. The completed micro - structure model is imported into optical design software for optical simulation. The simulation results of the three examples: spatial energy distribution and viewing angle curves are as Fig. 9 , 10 , 11. The comparison of the viewing angle curves of Example 1, Example 2, and Example 3 is as Fig.12 . The comparison data of the viewing angle curves are shown in Table 1 below:

[0101] Table 1 Comparison data of the viewing angle curves of Examples 1 - 6

[0102] Features Center brightness Peak brightness -30° scale -45° scale Example 1 Linear symmetry 310.8nit 310.8nit 21.8％ 0.89％ Example 2 Linear Asymmetry 280.4nit 301.3nit 11.9％ 0.04％ Example 3 5th order function, with a slightly smaller slope 331.0nit 335.0nit 16％ 0.23％ Example 4 5th order function, with a slightly larger slope 340nit 355.3nit 12.2％ 0.04％ Example 5 4th-order function, same as example 3 330.0nit 334.1nit 16.1％ 0.24％ Example 6 4th-order function, same as example 4 339.5nit 355.1nit 12.1％ 0.05％

[0103] The central brightness refers to the brightness perpendicular to the liquid crystal module; the peak brightness refers to the maximum brightness; the - 30° ratio refers to the ratio of the brightness at an angle of 30° with the vertical to the central brightness; the - 45° ratio refers to the ratio of the brightness at an angle of 45° with the vertical to the central brightness. The central brightness refers to the brightness when the human eye looks directly at the liquid crystal module, which is a key index, and the brighter this value is, the better; the - 30° / - 45° ratio represents the attenuation ratio of the brightness. The smaller the ratio, the greater the brightness attenuation and the better the anti - peeping effect.

[0104] Through optical simulation, Examples 3, 4, 5, and 6 have stronger brightness attenuation on one side than Example 1, which is manifested as stronger ability to absorb optical fibers on one side and is more suitable for the field of one - way light control of automotive displays. Examples 3, 4, 5, and 6 have larger aperture sizes and higher central brightness than Example 2.

[0105] According to the preparation method of the asymmetric structure privacy film in Example 3, the tool is first processed according to the designed function curve, and then the finished tool is processed into a mold. Then the microstructure is transferred to produce a semi-finished product. The cross-section effect of the semi-finished product is as follows: Figure 1 , and finally fill with black glue to complete the production of the finished privacy film.

[0106] At the same time, in order to prepare a control group, a finished privacy film was prepared according to the preparation method of the privacy film with a symmetrical structure in Example 1 to conduct an optical comparison test.

[0107] A method for preparing an asymmetric privacy film according to Embodiment 1-6 comprises:

[0108] Step (1), machining tool

[0109] According to the asymmetric structural characteristics, one side is linear, and its expression is: f(x) = tan(α)*x, where α is the bottom angle of the machining tool, and the range of angle α is 80-89°; the other side corresponds to the function;

[0110] Set the x and y series point coordinates with a step distance of 0.1μm to process the tool;

[0111] Step (2), preparing a mold roller

[0112] preparing a die roll on a copper roll using a cutter;

[0113] Step (3), microstructure transfer

[0114] Using a mold roller, the transmission unit resin material is UV-cured to transfer the microstructure on the mold roller to the surface of the substrate to form a transmission unit structure layer, i.e., a semi-finished material;

[0115] Step (4), preparing a mirror-finished roller

[0116] Use arc knife to cut the surface of copper roller or prepare mirror roller by grinding and polishing;

[0117] Step (5), preparing a privacy film

[0118] The light absorbing unit resin material is filled above the semi-finished transmission unit structure layer by using a mirror roller, and then cured by UV to obtain the finished privacy film.

[0119] We selected a 12-inch in-vehicle display screen for optical testing. The display screen structure from bottom to top includes a reflector, a light guide plate, a diffusion film, a prism film, and a polarized brightness enhancement film. The finished privacy film is placed between the polarized brightness enhancement film and the LCD panel. The viewing angle curve data is as follows: Fig.13 , the data are shown in Table 2 below:

[0120] Table 2 Comparison of viewing angle curves of display screen products of Examples 1-6

[0121] Features Center brightness Peak brightness -30° scale -45° scale Example 1 Linear symmetry 593.8nit 593.8nit 16.7％ 1.84％ Example 2 Linear Asymmetry 578.2nit 589.1nit 8.5％ 0.63％ Example 3 5th order function, with a slightly smaller slope 623.2nit 625.8nit 9.6％ 0.73％ Example 4 5th order function, with a slightly larger slope 630.3nit 632.1nit 8.5％ 0.61％ Example 5 4th-order function, same as example 3 622.9nit 625.3nit 9.4％ 0.74％ Example 6 4th-order function, same as example 4 631.3nit 630.2nit 8.6％ 0.62％

[0122] The actual effect is that the brightness attenuation ratio on one side is greater, and one side has better light absorption effect, so that there is less light on the upper side of the vertical viewing angle of the car display.

[0123] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. All equivalent changes and modifications made according to the content of the present invention are included in the patent scope of the present invention.

Claims

1. An asymmetric privacy film, whose light absorption unit structure is linear on one side, and its expression is: f(x) = tan(α)*x, where α is the bottom angle of the processing tool, and the range of angle α is 80-89°; the other side is a 5th or 4th order curve function, and the expression is: f(x) = ax 5 +bx 4 +cx 3 +dx 2 +ex+f; where 0 < a < 1, the function is a fifth-order function, b < 0, c > 0, and d * e * f ≠ 0. Or a = 0, the function is a fourth-order function, 0 < b < 1, c < 0, and d * e * f ≠ 0. When the tool processes this curve function, the step distance is set at 0.1 μm for the x and y series of point coordinates. The tool processing equipment processes the tool according to the x and y series of coordinates. x and y are the coordinates of the tool, representing the milling travel and path.

2. The privacy film according to claim 1, characterized in that: The angle α is 82°, 84°, 86°, or 88°.

3. The privacy film according to claim 1, characterized in that: When the function is a fifth-order function, a > 0.001, or 0.1, and a < 0.8, or 0.

5.

4. The privacy film according to claim 1, characterized in that: When the function is a fifth-order function, b > -100, or -15.

5. The privacy film according to claim 1, characterized in that: When the function is a 5th order function, c>3, or 700, and c<10 6 , or 10 5 .

6. The privacy film according to claim 1, characterized in that: When the function is a fourth-order function, b > 0.1, or 0.2, and b < 0.9, or 0.

8.

7. The privacy film according to claim 1, characterized in that: When the function is a fourth-order function, c > -100, or -50.

8. The privacy film according to claim 1, characterized in that: The function is a fifth-order curve function: f(x)=0.1019537*x 5 -13.9729399*x 4 +764.368664*x 3 -20864.0303523*x 2 +284218.6784201*x-(1.5461961*10 6 ).

9. The privacy film according to claim 1, characterized in that: The function is a 5th order curve function: f(x)=0.0060252*x 5 -0.4607229*x 4 +3.5311811*x 3 +542.2393839*x 2 -16709.8044609*x+144789.2715965.

10. The privacy film according to claim 1, characterized in that: The function is a fourth-order curve function: f(x)=0.3030147*x 4 -34.7157299*x 3 +1485.8215792*x 2 -28137.9222807*x+198864.1109986。 11. The privacy film according to claim 1, characterized in that: The function is a fourth-order curve function: f(x)=0.3903576*x 4 -44.5184641*x 3 +1897.5470278*x 2 -35808.923115*x+252363.0142044。 12. The method for preparing an anti-peeping film according to any one of claims 1 - 11, comprising: Step (1), processing the tool According to the asymmetric structure, one side is linear, and its expression is: f(x) = tan(α)*x, where α is the bottom angle of the machining tool, and the range of angle α is 80-89°; the other side is a 5th or 4th order curve function, and its expression is: f(x) = ax 5 +bx 4 +cx 3 +dx 2 +ex+f; where 0 < a < 1, the function is a fifth-order function, b < 0, c > 0, and d * e * f ≠ 0. Or a = 0, the function is a fourth-order function, 0 < b < 1, c < 0, and d * e * f ≠ 0. Set the step distance at 0.1 μm for the x and y series of point coordinates and process the tool. Step (2), preparing the mold roller Use the tool to prepare the mold roller on the copper roller. Step (3), micro-structure transfer Use the mold roller to transfer the micro-structure on the mold roller to the surface of the substrate through UV curing of the resin material of the transmission unit, forming a transmission unit structure layer, i.e., the semi-finished material. Step (4), preparing the mirror roller Use an arc tool to shave the surface of the copper roller or use a grinding and polishing method to prepare the mirror roller. Step (5), preparing the anti-peeping film Use the mirror roller to fill the resin material of the light-absorbing unit above the semi-finished transmission unit structure layer and cure it through UV to obtain the finished anti-peeping film.

13. The method for preparing the privacy film according to claim 12, characterized in that: Step (3), wherein the resin material of the transmission unit is acrylic resin.

14. The method for preparing the privacy film according to claim 12, characterized in that: Step (3), the UV curing method uses a mercury lamp or an LED method.

15. The method for preparing the privacy film according to claim 12, characterized in that: Step (3), the UV curing energy of the transmission unit resin and the light absorption unit resin is 300-1000mJ / cm 2 .

16. The method for preparing the privacy film according to claim 12, characterized in that: Step (5), the resin material of the light-absorbing unit is composed of a mixture of acrylic resin and carbon black paste.

17. The method for preparing the privacy film according to claim 12, characterized in that: Step (5), the UV curing method uses a mercury lamp or an LED method.

18. The method for preparing the privacy film according to claim 12, characterized in that: Step (5), the UV curing energy of the transmission unit resin and the light absorption unit resin is 800-1500mJ / cm 2 .

19. The anti-peeping film according to any one of claims 1 - 11 or the method for preparing an anti-peeping film according to any one of claims 12 - 18, wherein the film is in the form of a sheet or a roll.

20. The application of the anti-peeping film prepared by the method for preparing an anti-peeping film according to any one of claims 1 - 11 or the method for preparing an anti-peeping film according to any one of claims 12 - 18, which is applied to mobile phones, computers, and in-vehicle display devices.

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