Multi-angle peep-proof sheet and peep-proof display device

Abstract

A multi-angle peep-proof sheet and a peep-proof display device are used for being connected with a display and comprise a first polarizing layer, a first liquid crystal layer, a second polarizing layer, a second liquid crystal layer, a third polarizing layer and a compensation unit which are sequentially stacked from the surface of the display. The compensation unit is provided with at least one positive C-shaped compensation film clamped between the first polarization layer and the first liquid crystal layer or between the first liquid crystal layer and the second polarization layer. The sum of the thickness phase difference values (Rth) of the positive C-type compensation film ranges from-50 nm to-1050 nm. According to the peep-proof display device, the peep-proof purposes of small visual angle and multi-angle peep prevention are achieved through parameter selection of the positive C-shaped compensation film.

Description

Technical Field

[0001] The utility model relates to a display device, in particular to an anti-peeping display device. Background Art

[0002] In modern life, 3C devices for vehicles are gradually becoming popular. For the safety of vehicle driving, to avoid distraction of the driver's concentration or to protect the privacy of the driver using the vehicle 3C device. Therefore, how to reduce the light brightness on the line of sight of non-viewers to achieve the effect of protecting privacy or driving safety is relatively important.

[0003] Generally, the anti-peeping method for 3C devices is usually to attach a patch with anti-peeping function on the surface of the 3C display device to prevent non-users from viewing. However, since common anti-peeping patches have a symmetric anti-peeping effect, when used in vehicle 3C devices, for example, if the driver's viewing is prevented, the viewing quality of passengers will also be affected. Therefore, how to balance the viewing quality of passengers and make the display have an anti-peeping effect on the driver, or to protect the privacy of the driver's use, is an urgent problem to be overcome by those in the related technical fields. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a multi-angle anti-peeping sheet for a display with multi-angle anti-peeping.

[0005] The multi-angle anti-peeping sheet of the utility model is used to be joined with a display, and includes a first polarizing layer, a first liquid crystal layer, a second polarizing layer, a second liquid crystal layer, a third polarizing layer stacked in sequence, and a compensation unit. The compensation unit has at least one positive C-type compensation film sandwiched between the first polarizing layer and the first liquid crystal layer or between the first liquid crystal layer and the second polarizing layer.

[0006] The total thickness phase difference (Rth) of the positive C-type compensation film is between -50 nm and -1050 nm.

[0007] The total thickness phase difference (Rth) of the positive C-type compensation film is between -50 nm and -800 nm.

[0008] The total thickness phase difference (Rth) of the positive C-type compensation film is between -200 nm and -700 nm.

[0009] The total thickness phase difference (Rth) of the positive C-type compensation film is between -200 nm and -400 nm.

[0010] The total thickness phase difference (Rth) of the positive C-type compensation film is between -300 nm and -400 nm.

[0011] The compensation unit has two pieces of the positive C-type compensation films, which are respectively clamped between the first liquid crystal layer and the first polarizer layer and between the first liquid crystal layer and the second polarizer layer.

[0012] The compensation unit further has a negative C-type compensation film clamped between the second liquid crystal layer and the second polarizer layer, and the positive C-type compensation film clamped between the first liquid crystal layer and the first polarizer layer.

[0013] The thickness phase difference (Rth) of the negative C-type compensation film is between 50 nm and 300 nm.

[0014] Another object of the present invention is to provide an anti-peeping display device with different viewing angles for anti-peeping.

[0015] Therefore, the anti-peeping display device of the present invention includes a multi-angle anti-peeping sheet and a display.

[0016] The multi-angle anti-peeping sheet is combined with the display, and includes a first polarizer layer, a first liquid crystal layer, a second polarizer layer, a second liquid crystal layer, a third polarizer layer, and a compensation unit stacked in sequence. The compensation unit has at least one positive C-type compensation film clamped between the first polarizer layer and the first liquid crystal layer or between the first liquid crystal layer and the second polarizer layer.

[0017] The total thickness phase difference (Rth) of the positive C-type compensation films is between -50 nm and -1050 nm.

[0018] The display can be a self-luminous panel or a non-self-luminous panel. In the anti-peeping state, the light transmittance (T%) of the light observed from the multi-angle anti-peeping sheet at an observation angle greater than 30° is not greater than 4% of the light transmittance of the display.

[0019] The beneficial effect of the present invention is that through the parameter selection of the positive C-type compensation film, the anti-peeping purpose of a small viewing angle and multi-angle anti-peeping is achieved. Description of the Drawings

[0020] Figure 1 It is a schematic diagram showing the first embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram showing the second embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram showing the third embodiment of the present invention;

[0023] Figure 4 It is a schematic diagram showing the fourth embodiment of the present invention;

[0024] Figure 5It is a schematic diagram showing the schematic structure of integrating the multi-angle anti-peeping film of the present utility model with a display to form an anti-peeping display device;

[0025] Figure 6 It is a polarization angle measurement curve graph showing the relative brightness measurement results of the polarization angles corresponding to different parameters of the positive C-type compensation film in Specific Example 1;

[0026] Figure 7 It is a light transmittance measurement curve graph showing the light transmittance measurement results of the polarization angles of different parameters of the positive C-type compensation film in Specific Example 1;

[0027] Figure 8 It is a polarization angle measurement curve graph showing the relative brightness measurement results of the polarization angles corresponding to different parameters of the positive C-type compensation film in Specific Example 2;

[0028] Figure 9 It is a light transmittance measurement curve graph showing the light transmittance measurement results of the polarization angles of different parameters of the positive C-type compensation film in Specific Example 2;

[0029] Figure 10 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 30° of the parameter combination of two pieces of the positive C-type compensation film in Specific Example 3;

[0030] Figure 11 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 60° of the parameter combination of two pieces of the positive C-type compensation film in Specific Example 3;

[0031] Figure 12 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 75° of the parameter combination of two pieces of the positive C-type compensation film in Specific Example 3;

[0032] Figure 13 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 30° of the parameter combination of the positive C-type compensation film and the negative C-type compensation film in Specific Example 4;

[0033] Figure 14 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 60° of the parameter combination of the positive C-type compensation film and the negative C-type compensation film in Specific Example 4; and

[0034] Figure 15 It is a light transmittance measurement curve graph showing the light transmittance measurement results at a polarization angle of 75° of the parameter combination of the positive C-type compensation film and the negative C-type compensation film in Specific Example 4. Detailed implementation manners

[0035] The present utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0036] Before the present utility model is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

[0037] Regarding the related technical content, features and effects of the present utility model, they will be clearly presented in the following detailed description of the embodiments in conjunction with the reference drawings. In addition, it should be noted that the drawings of the present utility model only show the relative structure and / or position relationship between elements and are not related to the actual sizes of the respective elements.

[0038] The multi-angle anti-peeping film of the present utility model is used to be joined with a display to obtain a display device having multi-angle anti-peeping performance. The display device is particularly applicable to a vehicle-mounted display device and has a multi-angle anti-peeping effect.

[0039] Referring to Figure 1 , the first embodiment of the multi-angle anti-peeping film 2 includes a first polarizing layer 21, a first liquid crystal layer 22, a second polarizing layer 23, a second liquid crystal layer 24, a third polarizing layer 25, and a compensation unit 26 stacked in sequence from bottom to top.

[0040] The first polarizing layer 21, the second polarizing layer 23, and the third polarizing layer 25 are used to limit the passage of light in a specific direction. The first liquid crystal layer 22 and the second liquid crystal layer 24 can cooperate with an electric field to change the rotational arrangement direction of their liquid crystal molecules to control the entry and exit of light sources. Among them, the related structures and matching selections of the liquid crystal molecules of the first polarizing layer 21, the second polarizing layer 23, the third polarizing layer 25, the first liquid crystal layer 22, and the second liquid crystal layer 24 are well known in the technical field and are not the focus of the present utility model, so no further description will be given. In this embodiment, the axial angle (β) of the light absorption axis of the liquid crystal molecules of the second liquid crystal layer 24 is between 0 and β, where β is between 45° and less than 90°; the axial angle of the light absorption axis of the liquid crystal molecules of the first liquid crystal layer 22 is between (β - 90)° and β°, and the phase retardation between the first liquid crystal layer 22 and the second liquid crystal layer 24 is between 700 nm and 1200 nm.

[0041] The compensation unit 26 has a positive C-type compensation film 261 sandwiched between the first liquid crystal layer 22 and the second polarizing layer 23, and the total thickness phase difference (Rth) of the positive C-type compensation film 261 is between -50 nm and -1050 nm.

[0042] Referring to Figure 2 , the second embodiment of the multi-angle anti-peeping film 2 of the present utility model has a structure substantially the same as that of the first embodiment, except that the positive C-type compensation film 261 is sandwiched between the first polarizing layer 21 and the first liquid crystal layer 22.

[0043] Referring toFigure 3 For the third embodiment of the multi-angle anti-peeping film 2 of the present utility model, its structure is substantially the same as that of the first embodiment, except that the compensation unit 26 has two positive C-type compensation films 261, and the two positive C-type compensation films 261 are respectively sandwiched between the first liquid crystal layer 22 and the second polarizing layer 23 and between the first polarizing layer 21 and the first liquid crystal layer 22, and the sum of the thickness phase differences (Rth) of the two positive C-type compensation films 261 is between -50 nm and -1050 nm. By stacking multiple positive C-type compensation films 261 to form the required thickness phase difference (Rth), the selection of the positive C-type compensation film 261 can be more flexible.

[0044] It should be noted that whether the compensation unit 26 has one or two positive C-type compensation films 261, as long as the sum of the thickness phase differences (Rth) of the positive C-type compensation films 261 is controlled between -50 nm and -1050 nm, the multi-angle anti-peeping effect of this case can be achieved.

[0045] Preferably, the sum of the thickness phase differences (Rth) of the positive C-type compensation films 261 is between -50 nm and -800 nm.

[0046] Preferably, the sum of the thickness phase differences (Rth) of the positive C-type compensation films 261 is between -200 nm and -700 nm.

[0047] Preferably, the sum of the thickness phase differences (Rth) of the positive C-type compensation films 261 is between -200 nm and -400 nm.

[0048] Preferably, the sum of the thickness phase differences (Rth) of the positive C-type compensation films 261 is between -300 nm and -400 nm.

[0049] Refer to Figure 4 For the fourth embodiment of the multi-angle anti-peeping film 2 of the present utility model, its structure is substantially the same as that of the first embodiment, except that the compensation unit 26 has one positive C-type compensation film 261 and one negative C-type compensation film 262. The positive C-type compensation film 261 is sandwiched between the first polarizing layer 21 and the first liquid crystal layer 22, the negative C-type compensation film 262 is sandwiched between the second polarizing layer 23 and the second liquid crystal layer 24, the thickness phase difference (Rth) of the positive C-type compensation film 261 is between -50 nm and -1050 nm, and the thickness phase difference (Rth) of the negative C-type compensation film 262 is between 50 nm and 300 nm.

[0050] In some embodiments, the thickness phase difference (Rth) of the negative C-type compensation film 262 is between 100 nm and 300 nm.

[0051] By using the compensation unit 26 composed of the positive C-type compensation film 261 and the negative C-type compensation film 262 , the anti-peeping effect at different angles can be achieved by adjusting the total thickness phase difference of the compensation unit 26 .

[0052] The multi-angle privacy film 2 described in the first to fourth embodiments can be combined with a display to form a privacy display device having a multi-angle (different angles) privacy protection effect.

[0053] The display may be a self-luminous display panel, such as an organic light emitting diode (OLED) panel or a light emitting diode (LED) panel, or a liquid crystal display (LCD). Since the related structures of the organic light emitting diode (OLED) panel, the light emitting diode (LED) panel, and the liquid crystal display (LCD) are known in the art and are not the focus of the present invention, they will not be further described.

[0054] See also Figure 5 , wherein when the display is selected from a liquid crystal display 3, the liquid crystal display 3 comprises a backlight source 31, a brightness enhancement film 32 formed on the surface of the backlight source 31, a liquid crystal display panel 33 formed above the brightness enhancement film 32, and a polarizing film 34 formed on the surface of the liquid crystal display panel 33, the multi-angle privacy film 2 will be as follows Figure 5 (a), sandwiched between the brightness enhancement film 32 and the liquid crystal display panel 33. When the display is selected from a self-luminous display of an organic light emitting diode display 4, for example, the organic light emitting diode display 4 has a 1 / 4 wavelength plate 42 and an organic light emitting diode display panel 41, the multi-angle privacy film 2 will be as shown in FIG. Figure 5 As shown in (b), it is combined with the 1 / 4 wavelength plate 42 and is located on the light emitting surface (outermost side) of the organic light emitting diode display 4.

[0055] The anti-peeping display device of the present invention is described with reference to the following different specific examples and reference examples.

[0056] Specific example 1

[0057] The anti-peeping display device of the specific example 1 is a device that combines the multi-angle anti-peeping sheet 2 shown in the first embodiment with the Figure 5 The axial angles of the optical film layers of the multi-angle privacy film 2 and the liquid crystal display 3 of the specific example 1 are summarized in Table 1 below.

[0058] Table 1

[0059]

[0060]

[0061] Reference Example 1

[0062] The Reference Example 1 has a similar structure to the Specific Example 1, except that the positive C-type compensation film 261 is not provided in the Reference Example 1.

[0063] Refer to Figures 6 - 7 , Figures 6 - 7 is the anti-peeping test result of the anti-peeping display device shown in the Specific Example 1 and the Reference Example 1 at different thickness phase differences ( Figures 6 - 7 denoted by Rth(+C)) (0 nm (Reference Example 1), -100 nm, -300 nm, -500 nm) of the positive C-type compensation film 261. Among them, Figure 6 (b) is Figure 6 the enlarged view of the frame in (a).

[0064] From Figure 6 the results of the relative luminance, it can be seen that the relative luminance of the anti-peeping display device of the Specific Example 1 can be less than 3% when the polarization angle (Polarangle) θ is greater than +30°, and can also have an excellent anti-peeping effect when the polarization angle (Polar angle) θ is greater than +45°; while the relative luminance at the polarization angle (Polar angle) θ = -30° is greater than 80%, indicating that the anti-peeping display device of the present invention can indeed have a multi-angle anti-peeping effect on one side. In addition, from Figure 7 the results, it can be seen that when the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the range of -50 nm to -550 nm, the light transmittance at different polarization angles θ can be maintained at less than 3%, and thus has a better anti-peeping effect. When the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the ranges of -100 nm to -500 nm and -150 nm to -450 nm, the light transmittance at different polarization angles θ can be maintained at not more than 2% and thus can have a better anti-peeping effect.

[0065] Specific Example 2

[0066] The Specific Example 2 of the anti-peeping display device has a structure similar to that of the Specific Example 1. The difference is that the multi-angle anti-peeping sheet 2 of the Specific Example 2 has the structure shown in the Second Embodiment. The axis angles of the multi-angle anti-peeping sheet 2 of the Specific Example 2 and the respective optical film layers of the liquid crystal display 3 are sorted out in Table 2 below.

[0067] Table 2

[0068]

[0069] Refer to Figures 8 - 9 , Figure 8is the anti-peeping display device shown in the specific example 2 at different thickness phase differences of the positive C-type compensation film 261 ( Figures 8 - 9 represented by -Rth(+C)) (0nm, -200nm, -400nm, -600nm, -800nm) of the anti-peeping test results. Among them, Figure 8 (b) is Figure 8 an enlarged view of the frame in (a).

[0070] From Figure 8 the results of the relative luminance, it can be seen that the relative luminance of the anti-peeping display device of the specific example 2 can be less than 3% when the polarization angle (Polarangle) θ is greater than 30°, and can also have an excellent anti-peeping effect when the polarization angle (Polar angle) θ is greater than 45°; while the relative luminance when the polarization angle (Polar angle) θ = -30° can be greater than 80%, indicating that the anti-peeping display device of the present invention can indeed have a multi-angle anti-peeping effect. In addition, from Figure 9 the results, it can be seen that when the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the range of -200nm to -1050nm, the light transmittance at different polarization angles θ can be maintained at less than 3%, and thus has a better anti-peeping effect. And when the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the ranges of -300nm to -900nm, -400nm to -800nm, -500nm to -700nm, the light transmittance at different polarization angles θ can be maintained at no more than 2% and thus can have a better anti-peeping effect.

[0071] Specific example 3

[0072] The specific example 3 of the anti-peeping display device has a structure similar to that of the specific example 1. The difference is that the multi-angle anti-peeping sheet 2 of the specific example 3 has the structure shown in the third embodiment. The following Table 3 is the axis angle arrangement of each optical film layer of the multi-angle anti-peeping sheet 2 and the liquid crystal display 3 of the specific example 3.

[0073] Table 3

[0074]

[0075]

[0076] Refer to Figures 10 - 12 , Figures 10 - 12 is the anti-peeping display device shown in the specific example 3 at a thickness phase difference (Rth) of not less than -1050nm for a positive C-type compensation film 261 in combination with another different thickness phase difference ( Figures 10 - 12The anti-peeping test results of a positive C-type compensation film 261 of (-Rth(+C)) (0 nm, -100 nm, -200 nm, -300 nm) are shown.

[0077] From Figures 10 - 12 the light transmittance results, it can be seen that when the total thickness phase difference (Rth) of the compensation unit 26 is selected in the range of -50 nm to -1300 nm, the light transmittance of light with a polarization angle θ of 75° can be maintained at less than 4%, and the light transmittance of light with a polarization angle θ of 60° can also be maintained at less than 3%, showing good anti-peeping effects. When the total thickness phase difference (Rth) of the compensation unit 26 is selected in the ranges of -50 nm to -900 nm and -200 nm to -600 nm, the light transmittance at a polarization angle θ less than 60° can be maintained at no more than 2%, achieving better anti-peeping effects. Moreover, when the total thickness phase difference (Rth) of the compensation unit 26 is selected in the range of -200 nm to -400 nm, the light transmittance at different polarization angles θ can be maintained at no more than 2%, achieving the best anti-peeping effects.

[0078] Specific Example 4

[0079] Specific Example 4 of the anti-peeping display device has a structure similar to that of Specific Example 1. The difference lies in that the multi-angle anti-peeping sheet 2 of Specific Example 4 has the structure shown in the fourth embodiment. Table 4 below shows the axis angles of each optical film layer of the multi-angle anti-peeping sheet 2 and the liquid crystal display 3 in Specific Example 4.

[0080] Table 4

[0081]

[0082] Reference Example 2

[0083] Reference Example 2 has a structure similar to that of Specific Example 4. The difference lies in that Reference Example 2 only sets a negative C-type compensation film 262 and does not set a positive C-type compensation film 261.

[0084] Refer to Figures 13 - 15 , Figures 13 - 15 is the anti-peeping test results of the anti-peeping display device shown in Specific Example 4 when the thickness phase difference ( Figures 13 - 15 expressed as -Rth(+C)) of the positive C-type compensation film 261 ranges from -50 nm to -1050 nm and is paired with negative C-type compensation films 262 with different thickness phase differences ( Figures 13 - 15 expressed as Rth(-C)) (0 nm, 100 nm, 200 nm, 300 nm).

[0085] From Figures 13 - 15From the light transmittance results, when the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the range of -50 nm to -1050 nm, and the thickness phase difference (Rth) of the negative C-type compensation film 262 is selected in the range of 50 nm to 350 nm, the light transmittance at different polarization angles θ can be maintained at less than 3%, and thus has a good anti-peeping effect. When the thickness phase difference (Rth) of the positive C-type compensation film 261 is selected in the range of -100 nm to -900 nm, and at the same time the thickness phase difference (Rth) of the negative C-type compensation film 262 is selected in the range of 50 nm to 350 nm, the light transmittance at different polarization angles θ can be maintained at no more than 2% and thus can have a better anti-peeping effect.

[0086] The optimal parameters of the compensation films and the light transmittance brightness at different polarization angles for the specific examples 1 to 4 and the reference examples 1 to 2 are summarized in Table 5 below.

[0087] Table 5

[0088]

[0089] Specific Examples 5 to 8

[0090] For the anti-peeping display devices of the specific examples 5 to 8, the structure of the multi-angle anti-peeping sheet 2 is the same as that of the specific examples 1 to 4 respectively. The difference is that the display of the specific examples 5 to 8 is the organic light-emitting diode display 4 as shown in Figure 5 (b). The axis angles of the optical film layers of the multi-angle anti-peeping sheet 2 and the organic light-emitting diode display 4 for the specific examples 5 to 8 are summarized in Tables 6 to 9.

[0091] Table 6 (Specific Example 5)

[0092]

[0093] Table 7 (Specific Example 6)

[0094]

[0095]

[0096] Table 8 (Specific Example 7)

[0097]

[0098] Table 9 (Specific Example 8)

[0099]

[0100] Reference Examples 3, 4

[0101] Reference Examples 3 and 4 respectively have similar structures to Specific Examples 5 and 8. The difference is that no positive C-type compensation film 261 is provided in Reference Examples 3 and 4.

[0102] Specific Examples 5 to 8 have similar structures and similar anti-peeping effects compared to Specific Examples 1 to 4. Therefore, the light penetration results of Specific Examples 5 to 8 and Reference Examples 3 to 4 are summarized in Table 10, and the details are not elaborated here.

[0103] Table 10

[0104]

[0105]

[0106] As can be seen from the results in Table 10, after replacing the liquid crystal display 3 with the organic light-emitting diode display 4, the anti-peeping display device also has a considerable anti-peeping effect, and excellent anti-peeping results can be obtained at small angles (θ not greater than 30°).

[0107] In summary, for the multi-angle anti-peeping sheet 2 of the present invention, by making the compensation unit 26 have at least one positive C-type compensation film 261 and controlling the selection range of the thickness phase difference (Rth) of the positive C-type compensation film 261 to be between -50 nm and -1050 nm, through the selection and combination of the parameters and positions of the compensation unit 26, it can indeed achieve the anti-peeping purpose of having a small viewing angle and multi-angle anti-peeping in the applications of different types of displays.

[0108] However, the above are only the embodiments of the present invention, and the scope of implementation of the present invention cannot be limited thereby. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification still fall within the scope covered by the patent of the present invention.

Claims

1. A multi-angle privacy filter for engaging with a display, characterized in that: Comprising a first polarizer layer, a first liquid crystal layer, a second polarizer layer, a second liquid crystal layer, a third polarizer layer, and a compensation unit stacked in sequence, the compensation unit having at least one positive C-type compensation film sandwiched between the first polarizer layer and the first liquid crystal layer or between the first liquid crystal layer and the second polarizer layer, The total thickness retardation (Rth) of the positive C-type compensation film is between -50 nm and -1050 nm.

2. The multi-angle privacy filter according to claim 1, wherein The total thickness retardation (Rth) of the positive C-type compensation film is between -50 nm and -800 nm.

3. The multi-angle anti-peeping sheet according to claim 2, wherein The total thickness retardation (Rth) of the positive C-type compensation film is between -200 nm and -700 nm.

4. The multi-angle anti-peeping sheet according to claim 3, characterized in that, The total thickness retardation (Rth) of the positive C-type compensation film is between -200 nm and -400 nm.

5. The multi-angle privacy filter according to claim 4, wherein, The total thickness retardation (Rth) of the positive C-type compensation film is between -300 nm and -400 nm.

6. The multi-angle privacy filter according to claim 5, wherein The compensation unit has two pieces of the positive C-type compensation film, which are respectively sandwiched between the first liquid crystal layer and the first polarizer layer and between the first liquid crystal layer and the second polarizer layer.

7. The multi-angle anti-peeping sheet according to claim 1, wherein The compensation unit further has a negative C-type compensation film sandwiched between the second liquid crystal layer and the second polarizer layer, and the positive C-type compensation film sandwiched between the first liquid crystal layer and the first polarizer layer.

8. The multi-angle anti-peeping sheet according to claim 7, characterized in that, The thickness retardation (Rth) of the negative C-type compensation film is between 50 nm and 300 nm.

9. A privacy display device, comprising: A display; and A multi-angle privacy film, joined to the display, including a first polarizer layer, a first liquid crystal layer, a second polarizer layer, a second liquid crystal layer, a third polarizer layer, and a compensation unit stacked in sequence, the compensation unit having at least one positive C-type compensation film sandwiched between the first polarizer layer and the first liquid crystal layer or between the first liquid crystal layer and the second polarizer layer, The total thickness retardation (Rth) of the positive C-type compensation film is between -50 nm and -1050 nm.

10. The anti-peeping display device according to claim 9, wherein The display can be a self-luminous panel or a non-self-luminous panel. In the privacy state, the light transmittance (T%) of light observed from an observation angle greater than 30° of the multi-angle privacy film is not greater than 4% of the light transmittance of the display.

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