Electrochromic composition, privacy film and display device

Abstract

This application provides an electrochromic composition, a privacy screen, and a display device. The electrochromic composition includes: an acid-sensitive dye; the acid-sensitive dye can switch between a transparent state and a colored state when the proton concentration in the electrochromic composition changes; an electro-acid that can generate protons under the action of external electrons; an ionic liquid composed of dissociated ions; and a solvent; wherein the acid-sensitive dye, the electro-acid, the ionic liquid, and the solvent are mixed together; when the proton concentration of the electrochromic composition is 0, the acid-sensitive dye is in a transparent state; when the proton concentration of the electrochromic composition is greater than 0, the acid-sensitive dye is in a colored state. The electrochromic composition, privacy screen, and display device provided by this application have a privacy protection effect and a simple structure.

Description

Technical Field

[0001] This application relates to the field of privacy technology, and more particularly to an electrochromic composition, a privacy film, and an electronic device. Background Technology

[0002] Currently, mature electronic privacy screen protector technology utilizes polymer dispersed liquid crystal (PDLC) to scatter collimated light passing through the venetian blind film, enabling switching between privacy and non-privacy modes. This method requires adding a PDLC device layer on top of the original privacy venetian blind film, and further adding a collimating prism film to the backlight to improve light efficiency, resulting in a very complex film structure. A simpler design is to directly replace the black spacers in ordinary venetian blind film with an electrochromic material that can switch between transparent and black. To achieve a privacy effect, the thickness of the venetian blind film is generally designed to be greater than 100μm, while traditional electrochromic materials (tungsten oxide, amethyst, polymer electrochromic materials) can only achieve color change in film layers with a thickness of less than 10μm. This design is difficult to achieve with traditional electrochromic materials (tungsten oxide, amethyst, polymer electrochromic materials). Summary of the Invention

[0003] In view of this, this application provides an electrochromic composition with privacy protection, a privacy film with privacy protection and simple structure, and a display device.

[0004] To solve the above problems, the technical solution provided in this application is as follows:

[0005] This application provides an electrochromic composition comprising:

[0006] Acid-sensitive dye; the acid-sensitive dye is able to switch between a transparent state and a black state when the proton concentration in the electrochromic composition changes;

[0007] Electro-acids can produce protons under the influence of externally applied electrons;

[0008] Ionic liquids are composed of dissociated ions; and

[0009] Solvent;

[0010] The acid-sensitive dye, the electrochromic acid, the ionic liquid, and the solvent are mixed together; when the proton concentration of the electrochromic composition is 0, the acid-sensitive dye is in a transparent state; when the proton concentration of the electrochromic composition is greater than 0, the acid-sensitive dye is in a colored state.

[0011] In an optional embodiment of this application, the mass fraction ratio of the acid-sensitive dye, the electro-acid, the ionic liquid, and the solvent in the color-changing electrochromic composition is (0.1-2):(0.1-2):(2-10):(40-85).

[0012] In an optional embodiment of this application, the electrochromic composition further includes a transparent polymer, wherein the transparent polymer, the acid-sensitive dye, the electrochromic acid, the ionic liquid, and the solvent are mixed together.

[0013] In an optional embodiment of this application, the mass fraction ratio of the acid-sensitive dye, the electro-acid, the ionic liquid, the transparent polymer, and the solvent in the color-changing electrochromic composition is: (0.1-2):(0.1-2):(2-10):(5-50):(40-85).

[0014] In an optional embodiment of this application, the electrochromic composition is in a sol state.

[0015] In an optional embodiment of this application, the solvent has a mass fraction greater than 30% in the color-changing electrochromic composition.

[0016] In an optional embodiment of this application, the acid-sensitive dye is a fluorane derivative.

[0017] In an optional embodiment of this application, the electro-acid is at least one of hydroquinone and its derivatives, benzoquinone and its derivatives, and urea derivatives.

[0018] In an optional embodiment of this application, the ionic liquid is a molten salt, which refers to a salt that is in a molten state above 0°.

[0019] The ionic liquid is at least one of trifluoromethanesulfonylimide, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium hexafluorophosphate.

[0020] In an optional embodiment of this application, the solvent is polycarbonate or acetonitrile.

[0021] In an optional embodiment of this application, the transparent polymer is polymethyl methacrylate or polyvinyl butyral.

[0022] In an optional embodiment of this application, the coloring state is a gray state or a black state. The light transmittance of the electrochromic composition in the transparent state is greater than that of the electrochromic composition in the gray state, and the light transmittance of the electrochromic composition in the gray state is greater than that of the electrochromic composition in the black state.

[0023] This application also provides a privacy film, comprising:

[0024] First electrode layer;

[0025] A second electrode layer is disposed opposite to the first electrode layer; and

[0026] An electrochromic layer is located between the first electrode layer and the second electrode layer;

[0027] The electrochromic layer includes a substrate and a plurality of electrochromic units embedded in the substrate, wherein two adjacent electrochromic units are spaced apart by at least a portion of the substrate; each electrochromic unit includes the electrochromic composition as described above.

[0028] In an optional embodiment of this application, the privacy film further includes:

[0029] A first substrate layer is located on the side of the first electrode layer away from the electrochromic layer; and

[0030] The second base layer is located on the side of the second electrode layer away from the electrochromic layer;

[0031] The first electrode layer, the second electrode layer, the substrate, the first base layer, and the second base layer are all transparent.

[0032] In an optional embodiment of this application, when no voltage is applied between the first electrode layer and the second electrode layer, or when the voltage difference between the first electrode layer and the second electrode layer is 0, the electrochromic unit is in a transparent state; and

[0033] When the voltage difference between the first electrode layer and the second electrode layer is greater than 0, the electrochromic unit is in a colored state.

[0034] In an optional embodiment of this application, the voltage difference between the first electrode layer and the second electrode layer is 0V-5V.

[0035] In an optional embodiment of this application, the transmittance of the privacy film decreases as the voltage difference between the first electrode layer and the second electrode layer increases.

[0036] In an optional embodiment of this application, the thickness of the electrochromic layer is 100 μm to 150 μm.

[0037] In an optional embodiment of this application, the minimum visible angle of light passing through the privacy film is defined as θ, then tanθ=L1 / H;

[0038] Where L1 is the distance between two adjacent electrochromic units, and H is the thickness of the electrochromic unit in the stacking direction of the first electrode layer, the electrochromic layer and the second electrode layer;

[0039] The adjustable viewing angle of the light passing through the privacy film is θ to 90°.

[0040] This application also provides a display device, including a display panel; the display device further includes a privacy film as described above, the privacy film being located on the light-emitting side of the display panel.

[0041] The electrochromic composition provided in this application includes an acid-sensitive dye, an electrochromic acid, an ionic liquid, and a solvent. Under pressure, the electrochromic acid receives external electrons, undergoes a redox reaction, and releases protons into the electrochromic composition. The acid-sensitive dye reacts with the protons, resulting in a color-changing reaction. The electrochromic composition changes from a transparent state to a colored state (gray or black). The transparent state of the electrochromic composition has higher light transmittance, while the colored state (gray or black) has lower light transmittance. When this electrochromic composition is applied to a privacy screen, the voltage difference between the first and second electrode layers of the privacy screen can be controlled to switch the electrochromic layer between a colored state and a transparent state, thereby controlling the opening and closing of the privacy mode. Specifically, in the colored state, the privacy screen blocks screen light at large angles, and the privacy mode is activated; in the transparent state, the privacy screen allows screen light from all angles to pass through, and the privacy mode is deactivated. In addition, since the privacy screen protector in this case controls the opening and closing of the privacy mode by applying pressure between the first electrode layer and the second electrode layer of the privacy screen protector to control the switching between the transparent state and the colored state of the electrochromic layer of the privacy screen protector, it is not necessary to add a polymer dispersed liquid crystal (PDLC) device layer on top of the privacy screen protector and it is not necessary to add a collimating prism film on the backlight, so the structure is simple. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 Normalized transmittance spectra of the electrochromic composition provided in this application at different voltages.

[0044] Figure 2 Transmittance-voltage change curve of the electrochromic composition provided in this application.

[0045] Figure 3 A cross-sectional view of a privacy screen with privacy mode enabled, provided for some embodiments of this application.

[0046] Figure 4 A cross-sectional view of a privacy screen with privacy mode turned off, provided for some embodiments of this application.

[0047] Figure 5 This is a schematic diagram of the minimum viewing angle optical path of the privacy film provided in this application.

[0048] Figure 6 This is a schematic diagram of the adjustable optical path of the privacy film provided in this application.

[0049] Figure 7 This is a schematic diagram of a display device provided for some embodiments of this application. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0051] In the description of this application, it should be understood that the terms "upper," "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] Reference numerals and / or reference letters may be repeated in different embodiments of this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various implementations and / or settings discussed.

[0053] The electrochromic composition, privacy film, and display device provided in this application will be described in detail below with reference to specific embodiments and accompanying drawings.

[0054] This application provides an electrochromic composition comprising an acid-sensitive dye, an electrochromic acid, an ionic liquid, and a solvent, wherein the acid-sensitive dye, the electrochromic acid, the ionic liquid, and the solvent are mixed together.

[0055] In this electrochromic composition, the acid-sensitive dye can transition between a transparent state and a colored state when the proton concentration changes. Specifically, the acid-sensitive dye refers to a dye that undergoes a color reaction when the proton (H+) concentration of the system changes; it is generally a fluorane derivative, with a black colored state and a transparent bleached state. The fluorane is a compound formed by the condensation of phthalic anhydride and phenol.

[0056] The electro-acid can generate protons under the influence of external electrons. Specifically, the electro-acid refers to a molecule that can generate protons under the influence of external electrons, and generally includes hydroquinone and its derivatives, benzoquinone and its derivatives, urea derivatives, etc.

[0057] The ionic liquid is a liquid that is a molten salt at a certain temperature, composed of dissociated ions, and contains no solvent. The function of the ionic liquid is to increase the ionic conductivity of the electrochromic compound. Here, "certain temperature" refers to a temperature above 0°C. Preferably, the certain temperature is room temperature, such as 25°C.

[0058] Specifically, the ionic liquid is at least one of trifluoromethanesulfonylimide ([Bmim][Tf2N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]).

[0059] The solvent is polycarbonate or acetonitrile.

[0060] When the proton concentration of the electrochromic composition is 0, the acid-sensitive dye is in a transparent state; when the proton concentration of the electrochromic composition is greater than 0, the acid-sensitive dye is in a colored state. The colored state is either gray or black. Specifically, whether the colored state is gray or black also depends on the magnitude of the applied voltage.

[0061] The electrochromic principle of the electrochromic composition is as follows: under pressure, the electroacid receives external electrons, undergoes a redox reaction, and releases protons into the electrochromic composition. The acid-sensitive dye contacts the protons and undergoes a color reaction, causing the electrochromic composition to change from a transparent state to a colored state (gray or black). The transparent state of the electrochromic composition has higher light transmittance, while the colored state (gray or black) has lower light transmittance. Specifically, the light transmittance of the transparent state is greater than that of the gray state, and the light transmittance of the gray state is greater than that of the black state.

[0062] In an optional embodiment of this application, the electrochromic composition further includes a transparent polymer, wherein the transparent polymer, the acid-sensitive dye, the electrochromic acid, the ionic liquid, and the solvent are mixed together.

[0063] In an optional embodiment of this application, the mass fraction ratio of the acid-sensitive dye, the electro-acid, the ionic liquid, the transparent polymer, and the solvent in the color-changing electrochromic composition is: (0.1-2):(0.1-2):(2-10):(5-50):(40-85).

[0064] In an optional embodiment of this application, the solvent needs to have a mass fraction of more than 30% in the electrochromic composition so that the electrochromic composition is kept in a sol state.

[0065] The transparent polymer is at least one of poly(methyl methacrylate) (PMMA), polyvinyl butyral (PVB), etc. In an optional embodiment of this application, the transparent polymer is polymethyl methacrylate.

[0066] The transparent polymer serves as the framework of the electrochromic composition and prevents the acid-sensitive dye from agglomerating under an applied electric field. The solvent also acts as a plasticizer for the transparent polymer, keeping the electrochromic composition in a sol state.

[0067] If the transparent polymer is not added to the electrochromic composition at all, the acid-sensitive dye molecules will aggregate after one coloring reaction, causing some of the aggregated acid-sensitive dye molecules to fail to fade, resulting in black particles. If too much of the transparent polymer is added to the electrochromic composition, it will...

[0068] The electrochromic composition solidifies into a gel state, which reduces the thermal motion distance of molecules within the composition, making it impossible to achieve an electrochromic response at high film thicknesses. Therefore, it is necessary to adjust the viscosity of the electrochromic composition by changing the ratio of PMMA and PC to maintain the composition in a sol state.

[0069] In the sol state, the acid-sensitive dye molecules in the electrochromic composition, the

[0070] Electrochromic acid molecules and protons can migrate long distances under the action of molecular thermal motion, thereby enabling the electrochromic composition to achieve electrochromic response at high film thickness (100μm~150μm).

[0071] Please see Figure 1 , Figure 1 Normalized transmittance spectra of the electrochromic composition provided in this application at different voltages. Figure 1 It can be seen that under the applied voltage, the transmittance of the electrochromic composition to visible light gradually decreases as the voltage increases, and at this time the electrochromic composition is in a colored state.

[0072] In this embodiment, the voltage range is 0V-1.8V. However, the voltage is not limited to 0V-1.8V; 50V-1.8V is merely a preferred voltage. In practice, the voltage can be anywhere between 0V and 5V. When the voltage is 0V, the light transmittance of the electrochromic composition is 100%. When the voltage is 1.8V, the light transmittance of the electrochromic composition is close to 0%, i.e., close to a black state. Of course, for different wavelengths of light, the light transmittance of the electrochromic composition may also be greater than 0% when the voltage is 1.8V. For example, the transmittance of light with wavelengths of 380nm-430nm and 480nm-580nm is greater than 0%.

[0073] Please see Figure 2 , Figure 2 Transmittance-voltage variation curves of the electrochromic composition provided in this application. Figure 2 It can be seen that as the voltage gradually increases from 0V (e.g., 1.8V), the light transmittance of the electrochromic composition gradually decreases from 100% to 0%.

[0074] Depend on Figure 1 and Figure 2 It is known that the light transmittance of the electrochromic composition can be controlled by adjusting the voltage to switch between a transparent state and a colored state (gray or black state).

[0075] Please see Figure 3-4 This application also provides a privacy film 100, which is an electroluminescent privacy film.

[0076] The privacy film 100 includes a first electrode layer 10, a second electrode layer 20 disposed opposite to the first electrode layer 10, and an electrochromic layer 30 located between the first electrode layer 10 and the second electrode layer 20. The electrochromic layer 30 includes a substrate 31 and a plurality of electrochromic units 32 embedded within the substrate 31, with adjacent electrochromic units 32 spaced apart by at least a portion of the substrate 31; each electrochromic unit 32 includes the electrochromic composition described above.

[0077] When no voltage is applied between the first electrode layer 10 and the second electrode layer 20, or when the voltage difference between the first electrode layer 10 and the second electrode layer 20 is 0, the electrochromic unit 32 is in a transparent state. When a voltage is applied between the first electrode layer 10 and the second electrode layer 20 and the voltage difference is greater than 0, the electrochromic unit 32 is in a colored state, which includes a black state or a gray state.

[0078] Specifically, please refer to Figure 3 When the privacy film is in its color-coded state, it can block screen light at large angles, thus activating the privacy mode.

[0079] Specifically, please refer to Figure 4 When the privacy film 100 is in a transparent state, it allows screen light from various angles to pass through it, thus turning off the privacy mode.

[0080] In an optional embodiment of this application, the transmittance of the privacy film decreases as the voltage difference between the first electrode layer 10 and the second electrode layer 20 increases.

[0081] In an optional embodiment of this application, the voltage difference between the first electrode layer 10 and the second electrode layer 20 is 0V-5V. Further, the voltage difference between the first electrode layer 10 and the second electrode layer 20 is 0V-1.8V.

[0082] In an optional embodiment of this application, the thickness of the electrochromic layer 30 is 100μm to 150μm.

[0083] Specifically, the substrate 31 is made of transparent resin, which is used to space and protect adjacent electrochromic units 32.

[0084] Specifically, each electrochromic unit 32 has its two ends in contact with the first electrode layer 10 and the second electrode layer 20 respectively along the stacking direction of the first electrode layer 10, the electrochromic layer 30 and the second electrode layer 20, and the first electrode layer 10 and the second electrode layer 20 cooperate with the substrate 31 to seal the electrochromic unit 32.

[0085] In this embodiment, the plurality of electrochromic units 32 are arranged in a louvered manner within the substrate 31. In other embodiments, the arrangement of the plurality of electrochromic units 32 is not limited to a louvered shape, but can also be other array or non-array arrangements.

[0086] Please refer to it again. Figure 3 and Figure 4The privacy film 100 further includes a first base layer 40 and a second base layer 50, the first electrode layer 10 being located between the electrochromic layer 30 and the first base layer 40, and the second electrode layer 20 being located between the electrochromic layer 30 and the second base layer 50.

[0087] The first electrode layer 10, the second electrode layer 20, the substrate 31, the first base layer 40, and the second base layer 50 are all made of transparent materials.

[0088] The first substrate layer 40 serves to support the first electrode layer 10, the electrochromic layer 30, and the second electrode layer 20. The second substrate layer 50 serves to protect the second electrode layer 20.

[0089] Please see Figure 5 In an optional embodiment of this application, the minimum visible angle of light passing through the privacy screen 100 is defined as θ, then tanθ = L1 / H. Wherein, L1 is the distance between two adjacent electrochromic units 32, and H is the thickness of the electrochromic unit 32 in the stacking direction of the first electrode layer 10, the electrochromic layer 30, and the second electrode layer 20.

[0090] In this embodiment, θ is 25°, H = 150μm, L2 = 70μm, then tanθ = 0.47.

[0091] Wherein, L2 is the width in the arrangement direction of the plurality of electrochromic units 32, and in this embodiment, L2 = 35 μm. Of course, θ, L1, L2 and H are not limited to 25°, 150 μm, 70 μm and 35 μm.

[0092] Please see Figure 6 R1, R2, and R3 represent the screen illumination seen from different viewing angles. Without applied voltage, light with a wider viewing angle passes through the electrochromic unit 32 more, resulting in lower light transmittance. By changing the applied voltage, the color (transparent or tinted) of the electrochromic unit can be changed, thereby altering the light transmittance of the privacy film 100 and adjusting the viewing angle.

[0093] In one optional embodiment of this application, the adjustable viewing angle of light passing through the privacy film 100 is θ to 90°. In this embodiment, the adjustable viewing angle of light passing through the privacy film 100 is 25° to 90°.

[0094] Please see Figure 7This application also provides a display device 1000, including a display panel 200; the display device 1000 further includes a privacy film 100 as described above, the privacy film 100 being located on the light-emitting side of the display panel 200.

[0095] The display device 1000 can be an electronic device with display function, such as a display screen, mobile phone, laptop, iPad, or computer.

[0096] The electrochromic composition provided in this application includes an acid-sensitive dye, an electrochromic acid, an ionic liquid, and a solvent. Under pressure, the electrochromic acid receives external electrons, undergoes a redox reaction, and releases protons into the electrochromic composition. The acid-sensitive dye reacts with the protons, resulting in a color-changing reaction. The electrochromic composition changes from a transparent state to a colored state (gray or black). The transparent state of the electrochromic composition has higher light transmittance, while the colored state (gray or black) has lower light transmittance. When this electrochromic composition is applied to a privacy screen, the voltage difference between the first and second electrode layers of the privacy screen can be controlled to switch the electrochromic layer between a colored state and a transparent state, thereby controlling the opening and closing of the privacy mode. Specifically, in the colored state, the privacy screen blocks screen light at large angles, and the privacy mode is activated; in the transparent state, the privacy screen allows screen light from all angles to pass through, and the privacy mode is deactivated. In addition, since the privacy screen protector in this case controls the opening and closing of the privacy mode by applying pressure between the first electrode layer and the second electrode layer of the privacy screen protector to control the switching between the transparent state and the colored state of the electrochromic layer of the privacy screen protector, it is not necessary to add a polymer dispersed liquid crystal (PDLC) device layer on top of the privacy screen protector and it is not necessary to add a collimating prism film on the backlight. The structure is simple and the cost is low.

[0097] In addition, transparent polymers such as polymethyl methacrylate are added to the electrochromic composition. The transparent polymers can serve as the polymer backbone of the electrochromic composition and prevent acid-sensitive dyes from agglomerating under the action of an external electric field. This avoids the formation of black particles after coloring due to the agglomeration of acid-sensitive dye molecules, thereby further increasing the privacy protection effect.

[0098] In addition, the viscosity of the electrochromic composition can be adjusted by regulating the content of transparent polymer and solvent in the electrochromic composition, so that the electrochromic composition is kept in a sol state. In this state, the acid-sensitive dye molecules, electro-acid molecules and protons can migrate over long distances under the action of molecular thermal motion, which is conducive to achieving electrochromic response under high film thickness, thereby enabling the privacy film to achieve good privacy effect under high film thickness.

[0099] In addition, since more electrochromic units pass through when the viewing angle is wider, the light transmittance is lower. Therefore, by changing the applied voltage of the privacy film provided in this case, the light transmittance of the privacy film can be changed, thereby achieving the adjustment of the viewing angle.

[0100] In summary, although the present application has disclosed the preferred embodiments as described above, the above preferred embodiments are not intended to limit the present application. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be determined by the scope defined in the claims.

Claims

1. An electrochromic composition, characterized in that, include: Acid-sensitive dyes; When the proton concentration in the electrochromic composition changes, the acid-sensitive dye can switch between a transparent state and a colored state; Electro-acids can produce protons under the influence of externally applied electrons; Ionic liquids are composed of dissociated ions; and Solvent; The acid-sensitive dye, the electrochromic acid, the ionic liquid, and the solvent are mixed together; when the proton concentration of the electrochromic composition is 0, the acid-sensitive dye is in a transparent state; when the proton concentration of the electrochromic composition is greater than 0, the acid-sensitive dye is in a colored state. The electrochromic composition further includes a transparent polymer; The electrochromic composition is in a sol state.

2. The electrochromic composition according to claim 1, characterized in that, In the electrochromic composition, the mass fraction ratio of the acid-sensitive dye, the electrochromic acid, the ionic liquid and the solvent is (0.1~2):(0.1~2):(2~10):(40~85).

3. The electrochromic composition according to claim 1, characterized in that... The transparent polymer, the acid-sensitive dye, the electro-acid, the solvent, and the ionic liquid are mixed together.

4. The electrochromic composition according to claim 3, characterized in that, In the electrochromic composition, the mass fraction ratio of the acid-sensitive dye, the electrochromic acid, the ionic liquid, the transparent polymer, and the solvent is (0.1~2):(0.1~2):(2~10):(5~50):(40~85).

5. The electrochromic composition according to claim 4, characterized in that, In the electrochromic composition, the solvent has a mass fraction greater than 30%.

6. The electrochromic composition according to claim 1, characterized in that, The acid-sensitive dye is a fluorane derivative.

7. The electrochromic composition according to claim 1, characterized in that, The electro-acid is at least one of hydroquinone and its derivatives, benzoquinone and its derivatives, and urea derivatives.

8. The electrochromic composition according to claim 1, characterized in that, The ionic liquid is a molten salt, which refers to a salt that is in a molten state above 0°. The ionic liquid is at least one of trifluoromethanesulfonylimide, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium hexafluorophosphate.

9. The electrochromic composition according to claim 1, characterized in that, The solvent is polycarbonate or acetonitrile.

10. The electrochromic composition according to claim 1, characterized in that, The transparent polymer is polymethyl methacrylate or polyvinyl butyral.

11. The electrochromic composition according to claim 1, characterized in that, The electrochromic composition in the transparent state has a higher light transmittance than the electrochromic composition in the gray state, and the electrochromic composition in the gray state has a higher light transmittance than the electrochromic composition in the black state.

12. A privacy film, characterized in that, include: First electrode layer; The second electrode layer is disposed opposite to the first electrode layer; and An electrochromic layer is located between the first electrode layer and the second electrode layer; The electrochromic layer includes a substrate and a plurality of electrochromic units embedded in the substrate, wherein two adjacent electrochromic units are spaced apart by at least a portion of the substrate; each electrochromic unit includes the electrochromic composition as described in any one of claims 1-11.

13. The privacy film as described in claim 12, characterized in that, The privacy film also includes: A first substrate layer is located on the side of the first electrode layer away from the electrochromic layer; and The second base layer is located on the side of the second electrode layer away from the electrochromic layer; The first electrode layer, the second electrode layer, the substrate, the first base layer, and the second base layer are all transparent.

14. The privacy film as described in claim 12, characterized in that, When no voltage is applied between the first electrode layer and the second electrode layer, or when the voltage difference between the first electrode layer and the second electrode layer is 0, the electrochromic unit is in a transparent state. When the voltage difference between the first electrode layer and the second electrode layer is greater than 0, the electrochromic unit is in a colored state, which includes a black state or a gray state.

15. The privacy film as described in claim 14, characterized in that, The voltage difference between the first electrode layer and the second electrode layer is 0V-5V.

16. The privacy film as described in claim 15, characterized in that, The transmittance of the privacy film decreases as the voltage difference between the first electrode layer and the second electrode layer increases.

17. The privacy film as described in claim 14, characterized in that, The thickness of the electrochromic layer is 100µm~150µm.

18. The privacy film as described in claim 14, characterized in that, Define the minimum visible angle of light passing through the privacy film as θ, then tanθ = L1 / H; Where L1 is the distance between two adjacent electrochromic units, and H is the thickness of the electrochromic unit in the stacking direction of the first electrode layer, the electrochromic layer and the second electrode layer; The adjustable viewing angle of the light passing through the privacy film is θ~90°.

19. A display device, comprising a display panel; characterized in that, The display device further includes a privacy film as described in any one of claims 12-18, the privacy film being located on the light-emitting side of the display panel.

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