Optical film material and display equipment

Abstract

The invention provides an optical film material and display equipment. The optical film material comprises film-forming resin, a polymerizable monomer, a photosensitizer, a first initiator and a second initiator, the photosensitizer can generate photosensitive free radicals through reduction, and the oxidation potential of the first initiator is larger than the reduction potential of the second initiator and larger than the oxidation potential of the photosensitive free radicals. The optical film material has ground state high-temperature and high-pressure stability and high photosensitivity in an excited state, so that the optical film material is suitable for application scenes such as AR glasses / AR-HUD and the like.

Description

Technical Field

[0001] The present application relates to the field of display, and in particular to an optical film material and a display device. Background Art

[0002] Holography refers to the technique of reproducing a three-dimensional image of an object by recording the amplitude and phase distribution of light waves on a holographic recording medium. Holographic recording media are abundant and diverse, and holographic photopolymers, due to their flexible processing, wide sensitivity range, and high diffraction efficiency, are widely used in high-tech fields such as high-end anti-counterfeiting, holographic data storage, and holographic optical component manufacturing. However, to expand holographic photopolymers into broader applications, such as augmented reality (AR) and head-up displays (HUD), they must combine excellent optical quality, superior photosensitivity, high diffraction efficiency, and good heat resistance.

[0003] For AR glasses / AR-HUD and other scene applications, due to the optical design and different types of glass surface angles, holographic photopolymer materials are required to undergo special and rigorous process treatments (such as high temperature and high pressure) before holographic recording, and then holographic recording is carried out to achieve excellent diffraction efficiency, optical performance, etc. This requires that holographic photopolymer materials need to maintain excellent stability in extreme environments such as high temperature and high pressure, and avoid problems such as film fogging caused by side reactions of thermal polymerization of monomers under high temperature and high pressure. At the same time, after experiencing high temperature and high pressure, the holographic photopolymer material must still maintain excellent photosensitivity during the exposure stage, that is, a polymer can be used to form a grating with high diffraction efficiency with an extremely low exposure dose. However, there is a certain contradiction between the high temperature and high pressure stability in the ground state and the high photosensitivity in the excited state. That is, the existing holographic photopolymer materials cannot take into account both the high temperature and high pressure stability in the ground state and the high photosensitivity in the excited state, resulting in the existing holographic photopolymer materials not being widely used in application scenarios such as AR glasses / AR-HUD. Summary of the Invention

[0004] The present application provides an optical film material and a display device to improve the high-temperature and high-pressure stability of the optical film material in the ground state and the high photosensitivity in the excited state.

[0005] In a first aspect, the present application provides an optical film material, which includes a film-forming resin, a polymerizable monomer, a photosensitizer, a first initiator and a second initiator. The photosensitizer can generate photosensitive free radicals through reduction, and the oxidation potential of the first initiator is greater than the reduction potential of the second initiator, which is greater than the oxidation potential of the photosensitive free radicals.

[0006] The optical film material of the present application, by introducing a first initiator and a second initiator, because the oxidation potential of the first initiator is higher than the oxidation potential of the photosensitive free radical, under illumination, the first initiator can react with the photosensitizer, and the first initiator is oxidized to produce a first free radical, which can trigger the polymerization reaction of the polymerizable monomer. The photosensitizer is reduced to form a photosensitive free radical, but the photosensitive free radical is an inert free radical and cannot trigger the polymerization of the polymerizable monomer. In addition, because the reduction potential of the second initiator is higher than the oxidation potential of the photosensitive free radical, under illumination, the second initiator can be reduced to form a second free radical, which can trigger the polymerization of the polymerizable monomer. At this time, the photosensitive free radical can be oxidized to form the original photosensitizer. Therefore, the optical film material of the present application, by introducing the first initiator and the second initiator, can achieve a dual redox reaction, and can produce a maximum of two active free radicals under one photon irradiation, that is, the quantum yield can be increased by up to 200%, making the optical film material highly photosensitive. At the same time, the oxidation potential of the first initiator is greater than the reduction potential of the second initiator, so the second initiator does not undergo a redox reaction with the first initiator. Therefore, under high temperature and high pressure, a side reaction occurs between the two. Therefore, the optical film material of the present application, through the rational selection of the first initiator, the second initiator, and the photosensitizer, can meet the requirements of stability under high temperature and high pressure and high photosensitivity during exposure.

[0007] In one implementation, the oxidation potential of the first initiator may be 0.2 V to 2 V. In one implementation, the reduction potential of the second initiator may be -1.2 V to 0.4 V. In one implementation, the oxidation potential of the photosensitive free radical may be -0.2 to -0.01 V. The redox potential of the first initiator, the redox potential of the second initiator, and the redox potential of the photosensitive free radical are all based on the redox potential of ferrocene as an internal standard, i.e., 0 V as the benchmark standard.

[0008] In one implementation, the photosensitizer accounts for 0.001-0.5% by weight of the optical film. A too low photosensitizer content can reduce free radicals, hindering the polymerization reaction. An excessive amount of photosensitizer can lead to excess photosensitizer, making subsequent removal more difficult and affecting the imaging quality of subsequent display devices.

[0009] In one embodiment, the mass proportion of the first initiator in the optical film material may be 0.1-10%. In another embodiment, the mass proportion of the second initiator in the optical film material may be 0.05-3%. The content of the first initiator and the second initiator determines the number of active free radicals generated, affecting the polymerization rate of the polymerizable monomer and the degree of polymerization of the final polymer. Too low or too low a content of the first initiator and the second initiator is not conducive to the formation of a polymer with the desired degree of polymerization, which in turn affects the refractive index of the formed grating.

[0010] In one embodiment, the first initiator can be selected from at least one of alkylaryl ammonium borate, secondary aliphatic, secondary aromatic amines, tertiary aliphatic, and tertiary aromatic amines. In one embodiment, the second initiator can be selected from at least one of iodonium salts, sulfonium salts, pyridinium salts, diazonium salts, persulfates, benzoyl peroxides, and compounds containing alkyl free radicals. In one embodiment, the photosensitizer can be selected from at least one of anthocyanins, coumarins, dibenzopyrazines, phenothiazines, phenoxazines, pyrrole borons, and triarylmethane compounds.

[0011] In one implementation, after the optical film is heat-treated at 110-150°C for 30-120 minutes, in the ultraviolet absorbance test, the absorbance change value T at a wavelength of 460nm is 460 ≤10%, absorbance change value T at 532nm wavelength 532 ≤10%, absorbance change value T at 640nm wavelength 640 ≤40%.

[0012] In one implementation, after the optical film material is heat-treated at 110-150° C. for 30-120 minutes, the conversion rate of double bonds in the molecular structure of the optical film material is ≤15%.

[0013] In one implementation, after the optical film is heat-treated at 110-150° C. for 30-120 minutes, the haze of the optical film is ≤4%.

[0014] In one implementation, after the optical film is exposed to ultraviolet-visible light, in the ultraviolet absorbance test, the absorbance change value T at a wavelength of 460nm is 460 ≤5%, absorbance change value T at 532nm wavelength 532 ≤5%, absorbance change value T at 640nm wavelength 640 ≤20%.

[0015] Among them, the data in the above-mentioned possible implementation methods of the present application, such as the oxidation potential of the first initiator, the reduction potential of the second initiator, the oxidation potential of the photosensitive free radical, the absorbance change value, the haze and other data, when measured, the values ​​within the engineering measurement error range should be understood to be within the range specified in the present application.

[0016] In a second aspect, the present application provides a display device, which includes a substrate and an optical film material provided on the substrate.

[0017] The optical film material in the display device of the present application can form a holographic optical element after exposure. The holographic optical element can replace lenses, gratings, reflectors or more complex optical elements in the optical system and can be applied to scenarios such as vehicle-mounted head-up display (HUD), AR glasses, and holographic 3D projection. For example, in AR glasses or vehicle-mounted head-up display (AR-HUD) devices, the holographic optical element is clamped in the windshield or attached to the glass surface. Through holographic exposure, all the information of the light is recorded. Combined with the transmission and reflection functions of the holographic optical element, specific optical design, excellent diffraction efficiency, and transmittance, it can achieve a 3D stereoscopic effect projected in front of the human eye. Combined with the high transmittance of the optical film, it can achieve the mutual combination of virtual and reality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the reaction process of the optical film material according to an embodiment of the present application after being exposed to light;

[0019] Figure 2 is the UV-Vis transmittance of each optical film material before exposure with and without heating treatment;

[0020] Figure 3 This is a test chart of the polymerization rate of each optical film material after blue light exposure;

[0021] Figure 4 This is a test chart of the polymerization rate of each optical film after green light exposure;

[0022] Figure 5 This is a test chart of the polymerization rate of each optical film material after red light exposure;

[0023] Figure 6 The light transmittance of each optical film material after being directly exposed without heating treatment;

[0024] Figure 7 The transmittance of each optical film material after being heated and then exposed;

[0025] Figure 8 The transmittance curve of a sample measured by a UV-visible spectrophotometer in the 400-800nm ​​band is shown;

[0026] Figure 9 1 is a schematic structural diagram of AR glasses according to an embodiment;

[0027] Figure 10 The figure is a schematic structural diagram of a vehicle-mounted head-up display device according to an embodiment. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0029] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "above", "the", and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0030] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0031] For easier understanding, the following terms are explained first.

[0032] Diffraction efficiency: When the incident angle of the probe light meets the Bragg condition, the intensity of the diffracted light of the holographic grating reaches its maximum. The incident angle at this time is recorded as the Bragg angle. The ratio of the diffracted light intensity to the sum of the intensities of the diffracted light and the transmitted light is the diffraction efficiency of the grating.

[0033] Haze: refers to the percentage of transmitted light intensity that deviates from the incident light by more than 2.5° to the total transmitted light intensity. The greater the haze, the lower the gloss and transparency of the film.

[0034] Transmittance: It indicates the ability of light to pass through a medium. It is the percentage of the luminous flux passing through a transparent or translucent body to its incident luminous flux.

[0035] Refractive index modulation: In a holographic grating, the refractive index is distributed in the form of a sine curve along the grating vector direction, and the refractive index modulation is the amplitude of the sine curve.

[0036] For application scenarios such as AR glasses / AR-HUD, holographic photopolymers generally need to have the following properties: 1) After a long period of high-temperature and high-pressure module processing, the material performance does not deteriorate, and it can maintain high photosensitivity and bleachability, and the monomer does not participate in side reactions; 2) In subsequent holographic recording, it can be quickly exposed to form a grating, providing high diffraction efficiency; 3) The photosensitizer in the holographic photopolymer can be completely bleached in a short time to achieve industrial production.

[0037] The present invention provides an optical film material that can be used in AR glasses / AR-HUD and other application scenarios. After exposure, the optical film material can form a holographic optical element to achieve a display function.

[0038] The optical film material of the embodiments of the present application may include a film-forming resin, a polymerizable monomer, a photosensitizer, a first initiator, and a second initiator. Upon exposure to light, the polymerizable monomer in the optical film material of the embodiments of the present application polymerizes under the action of the first initiator and the second initiator to form a polymer. This polymer can function as a grating. The polymer's properties, such as its size and refractive index, can be designed based on the specific application scenario.

[0039] The film-forming resin serves as a base resin and provides film-forming properties. The film-forming resin may be, for example, acrylic resin or polymethyl methacrylate.

[0040] The polymerizable monomer is used to form a polymer when exposed to light, thereby forming a grating in the optical film. The polymerizable monomer has a high refractive index. For example, the polymerizable monomer has a refractive index of ≥1.5 when exposed to light with a wavelength below 589 nm. The polymerizable monomer can be selected from the group consisting of acrylates, methacrylates, vinyls, and vinyl ethers.

[0041] Illustratively, the polymerizable monomer preferably has the following chemical structure: Wherein, R1=H or CH3; R2 is one or more of phenethyl, phenoxyethyl, o-phenylphenethoxy, 4-(1-methyl-1-phenylethyl)phenoxyethyl, 2,4,6-tribromophenyl, 2,4,6-tribromophenoxyethyl, pentabromophenyl, pentabromophenoxy, naphthyl, naphthyloxy, 1,3-bis(thiophen-2-ylthio)propane-2-yl, 1,3-bis((4-(phenylthio)phenyl)thio)propane-2-yl, and 1,3-bis((4-bromophenyl)thio)propane-2-yl.

[0042] The photosensitizer can react with the first initiator, such as being reduced by the first initiator to generate a photosensitive free radical. The photosensitive free radical can then react with the second initiator, such as being oxidized by the second initiator to generate a photosensitizer. The photosensitizer can include red light photosensitizers, green light photosensitizers, and blue light photosensitizers. The photosensitizers used exhibit a thermogravimetric loss of less than 1.2 wt% during heating from room temperature to 200°C in a thermogravimetric test.

[0043] It should be noted that, before exposure to light, the optical film material of the present application contains the polymerizable monomer in monomeric form, and the first and second initiators do not react with the photosensitizer. After exposure to light, the first and second initiators react with the photosensitizer to generate free radicals, which in turn induce polymerization of the polymerizable monomer. Following the polymerization reaction, the optical film material contains virtually no polymerizable monomer, replaced by a polymer. The polymer can form gratings with varying properties depending on factors such as light intensity and type.

[0044] Figure 1 This is a schematic diagram of the reaction process of the optical film material of this application after light exposure. Figure 1 As shown, under illumination, the first initiator reacts with the photosensitizer, causing oxidation of the first initiator to produce a first free radical, which then initiates polymerization of the polymerizable monomer. The photosensitizer is reduced to form a photosensitive free radical, which is an inert free radical and cannot initiate polymerization of the polymerizable monomer. Simultaneously, the second initiator reacts with the photosensitive free radical and is reduced to form a second free radical, which then initiates polymerization of the polymerizable monomer. The photosensitive free radical that reacts with the second initiator is oxidized to form the original photosensitizer. In this process, the introduction of the first and second initiators enables a dual redox reaction, generating a maximum of two active free radicals per photon, increasing the quantum yield by up to 200%, and imparting high photosensitivity to the optical film.

[0045] In order to prevent the first initiator from being oxidized by the second initiator in an environment such as high temperature or high pressure, the redox potentials of the first initiator and the second initiator are limited in the optical film material of the present application. That is, the oxidation potential of the first initiator is greater than the reduction potential of the second initiator and the oxidation potential of the photosensitive free radical. Through the above definition, the oxidation potential of the first initiator is greater than the reduction potential of the second initiator, and the second initiator will not undergo a redox reaction with the first initiator. Therefore, under high temperature and high pressure, a side reaction will also occur between the two. Therefore, the optical film material of the present application, through the reasonable selection of the first initiator, the second initiator and the photosensitizer, can meet the requirements of stability under high temperature / high pressure and high photosensitivity when exposed.

[0046] Conventional optical films typically contain only one initiator. However, this application introduces two initiators to achieve an increase in quantum yield under illumination. To prevent the second initiator from adversely affecting the optical film's material system, the second initiator II must meet the following requirements: ① In its ground state (i.e., when not exposed to light), it must not undergo a redox reaction with the first initiator; and ② In its excited state (i.e., when exposed to light), it must react with photosensitive free radicals. Specifically, the second initiator must have the ability to oxidize photosensitive free radicals but not the first initiator.

[0047] The first initiator and the second initiator can both generate free radicals during the reaction process with the photosensitizer to initiate a polymerization reaction of the polymerizable monomer and promote the progress of the polymerization reaction.

[0048] Wherein, the oxidation potential of the first initiator may be 0.2V to 2V. Exemplarily, the lowest value of the oxidation potential of the first initiator may be, for example, 0.2V, 0.3V, 0.4V, 0.5V, 0.6V, 0.7V, 0.8V, 0.9V, 1.0V or a value between any two of the above values, and the highest value of the oxidation potential of the first initiator may be, for example, 2V, 1.9V, 1.8V, 1.7V, 1.6V, 1.5V, 1.3V, 1.2V, 1.1V or a value between any two of the above values. The first initiator may be selected from at least one of alkyl aryl borate, secondary aliphatic, secondary aromatic amines, tertiary aliphatic, and tertiary aromatic amines. The first initiator may also be selected from other substances with reducing or electron-donating properties that can react with the photosensitizer. Figure 1 The Norrish II type photoinitiation mechanism is shown.

[0049] The reduction potential of the second initiator may be -1.2 V to 0.4 V. For example, the lowest value of the reduction potential of the second initiator may be, for example, -1.2 V, -1.1 V, -1.0 V, -0.9 V, -0.8 V, -0.7 V, -0.6 V, or a value between any two of the above values, and the highest value of the reduction potential of the second initiator may be, for example, 0.4 V, 0.3 V, 0.2 V, 0.1 V, 0.0 V, -0.1 V, -0.2 V, -0.3 V, -0.4 V, -0.5 V, or a value between any two of the above values. The second initiator may be selected from at least one of iodonium salts, sulfonium salts, pyridinium salts, diazonium salts, persulfates, benzoyl peroxides, and compounds having alkyl radicals.

[0050] Wherein, the iodonium salt can be selected from at least one of the following compounds:

[0051]

[0052] Wherein, the sulfonium salt can be selected from at least one of the following compounds:

[0053]

[0054] Wherein, the diazonium salt can be selected from at least one of the following compounds:

[0055]

[0056] Wherein, the pyridinium salt can be selected from at least one of the following compounds:

[0057]

[0058] Wherein, the alkyl radical can be selected from at least one of the following compounds:

[0059]

[0060] The second initiator may be selected from at least one of the following compounds in addition to the compounds listed above:

[0061]

[0062]

[0063] Table 1 lists the redox potentials of several typical second initiators.

[0064] Table 1

[0065]

[0066]

[0067] Table 1 (continued)

[0068]

[0069]

[0070] Table 1 (continued)

[0071]

[0072] The oxidation potential of the photosensitive free radical may be -0.2 to -0.01 V. For example, the lowest oxidation potential of the photosensitive free radical may be -0.2 V, -0.19 V, -0.18 V, -0.17 V, -0.16 V, -0.15 V, -0.14 V, -0.13 V, -0.12 V, -0.11 V, -0.10 V, -0.09 V, or any value between the above two values. The highest oxidation potential of the photosensitive free radical may be -0.01 V, -0.02 V, -0.03 V, -0.04 V, -0.05 V, -0.06 V, -0.07 V, -0.08 V, or any value between the above two values. The photosensitizer may be, for example, at least one of anthocyanin, coumarin, dibenzopyrazine, phenothiazine, phenoxazine, pyrrole boron, and triarylmethane compounds.

[0073] In the embodiment of the present application, the weight percentage of the first initiator in the optical film is 0.1-10%, such as 1-9%, such as 2-8%, such as 3-8%, and such as 3-7%. For example, the weight percentage of the first initiator in the optical film can be 0.1%, 0.5%, 0.8%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%, or a value between any two of the above values.

[0074] The weight percentage of the second initiator in the optical film is 0.05-3%, such as 0.1-3%, 0.5-2.5%, or 1-2%. For example, the weight percentage of the second initiator in the optical film can be 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, or any value between the above two values.

[0075] The mass proportion of the photosensitizer in the optical film is 0.001-0.5%, such as 0.005-0.5%, such as 0.1-0.5%, and such as 0.1-0.4%. For example, the mass proportion of the photosensitizer in the optical film can be 0.001%, 0.005%, 0.01%, 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, or a value between any two of the above values.

[0076] The optical film material of the embodiment of the present application is subjected to a heat treatment at 110-150° C. for 30-120 min. In the ultraviolet absorbance test, the absorbance change value T at a wavelength of 460 nm is 460 ≤10%, absorbance change value T at 532nm wavelength 532 ≤10%, absorbance change value T at 640nm wavelength 640 ≤40%. Double bond conversion rate in the molecular structure of the optical film is ≤15%. Haze of the optical film is ≤4%. In addition, after the optical film of this embodiment is exposed to ultraviolet-visible light, the absorbance change value T at a wavelength of 460nm is ≤40%. 460 ≤5%, absorbance change value T at 532nm wavelength 532 ≤5%, absorbance change value T at 640nm wavelength 640 ≤20%.

[0077] The structure of the optical film material of the present application will be explained below with reference to specific embodiments and comparative examples.

[0078] Table 2 lists the names and abbreviations of the substances used in the following examples and comparative examples.

[0079] Table 2

[0080]

[0081] Example 1

[0082] The optical film material of this embodiment is prepared by the following method.

[0083] S1. Solution preparation

[0084] Weigh 1g of film-forming resin and dissolve it in 3ml of dichloromethane solvent. Let it dissolve for 1h to obtain a resin solution.

[0085] Prepare methanol mother liquor containing red photosensitizer, green photosensitizer and blue photosensitizer, and stir thoroughly for 1 hour to obtain a photosensitizer solution;

[0086] The polymerizable monomer ABPEF with a high refractive index and the first initiator MDEA are sequentially added to the resin solution according to the required ratio, and then the photosensitizer solution is added and stirred evenly at room temperature.

[0087] S2. Film Preparation

[0088] The prepared solution was filtered using a 3 μm filter head and degassed using a degassing machine; a thin film was obtained after coating using a 75 μm square film forming apparatus; the prepared film was placed in an oven at 60°C for 20 minutes to remove the solvents of dichloromethane and methanol to obtain an optical film material; the optical film material was removed from the oven and attached with a protective film.

[0089] S3, exposure and post-processing

[0090] Remove the release film on the surface of the optical film, attach the optical film to the glass surface, and use a blue light 460nm, green light 532nm, and red light 640nm laser at 0.5mW / cm 2 The samples were exposed to a power density of 100 nm for 60 seconds. The exposed samples were heated at 60°C for 5 minutes to promote polymerization. They were then bleached with a white LED for 1 hour to remove any remaining photosensitizer.

[0091] Examples 2-3 and Comparative Example 1

[0092] Optical films were prepared in Examples 2-3 and Comparative Example 1 by referring to the preparation process of Example 1. The types and addition amounts of the reagents used in each Example and Comparative Example are listed in Table 3.

[0093] Table 3

[0094]

[0095] Performance Testing

[0096] 1. Test the UV-Vis transmittance of each optical film material before exposure with and without heating treatment. The test results are as follows: Figure 2 The heating temperature is 100-150°C and the heating time is 10-120 minutes.

[0097] 2. Test the polymerization rate of each optical film after exposure. The polymerization rate change of the optical film after exposure is shown in the figure below: Figure 3-Figure 5 shown.

[0098] 3. Test the transmittance of each optical film material after direct exposure without heating treatment. The test results are as follows: Figure 6 shown.

[0099] 4. Test the transmittance of each optical film after heating and then exposure. The test results are as follows: Figure 7 The heating temperature is 100-150°C and the heating time is 10-120 minutes.

[0100] The diffraction efficiency test method is as follows: use an ultraviolet-visible spectrophotometer to measure the transmittance of the sample in the 400-800nm ​​band. Figure 8 The transmittance curve is obtained using Figure 8 The curve shown obtains the minimum transmittance (T min ) and the baseline transmittance (T A ), and calculate the diffraction efficiency according to formula 1:

[0101]

[0102] like Figure 2 As shown, the optical film materials corresponding to Examples 1-3 have no significant change in light transmittance after high-temperature treatment compared to the film materials without high-temperature treatment. However, the optical film material of Comparative Example 1 has a significant change in light transmittance after high-temperature treatment. After heat treatment, the optical film materials of Comparative Example 1 and Examples 1-3 will show a certain degree of fading in the R / G / B band, that is, an increase in light transmittance and a decrease in absorbance, especially in the red light band. By comparing Comparative Example 1 (without the second initiator) and Examples 1-3 (with the second initiator), it can be seen that the addition of the second initiator can alleviate the fading problem in the red light band, that is, the failure problem of the red light photosensitizer. Therefore, the introduction of the second initiator can effectively suppress the failure of the red light photosensitizer caused by heating.

[0103] The specific transmittance changes at several wavelengths are listed in Table 4.

[0104] Table 4

[0105]

[0106] According to the data in Table 4, the optical film material of Comparative Example 1, which was heated before exposure, has a blue light wavelength λ 460 and green wavelength λ 532 The transmittance under the condition of red light is basically unchanged and is below 5%. 640 The transmittance changes under different conditions are relatively large, about 10%. 460 、Green light wavelength λ 532 and red light wavelength λ 640 The light transmittance under the conditions of FIG. 5 is substantially unchanged and is below 5%. Thus, it can be seen that the optical film material of the embodiment of the present application has higher stability.

[0107] Figure 3-Figure 5 This is a comparison chart of the polymerization rates of different optical film materials in different bands. Figure 3 This is a comparison chart of polymerization rates under the blue light band. Figure 4 This is a comparison chart of polymerization rates under green light band. Figure 5 This is a comparison chart of polymerization rates under red light band. Figures 3 to 5 The conversion rate is the conversion rate of monomer double bonds in optical film materials under the irradiation of blue / green / red light bands (peak value is 1628-1644cm -1 ), the polymerization rate is characterized by the curve of the conversion rate of the polymerizable monomer over time. Among them, the power density of blue light and green light is 0.3mw / cm 2 , the power density of red light is 0.5mw / cm 2 , exposure starts at 10 seconds.

[0108] like Figures 3 to 5 As shown, in the blue light band, the polymerization rate of the optical film materials corresponding to Examples 1-3 is substantially higher than that of Comparative Example 1. Compared with Comparative Example 1, Examples 1-3 exhibit a faster polymerization rate, that is, the conversion rate is significantly better than that of Comparative Example 1 10 seconds after the start of exposure. Figures 3 to 5 The conversion rate in the figure is over 100% and the curve jitter is due to the semi-quantitative nature of the IR test and the interference of the PET film. The optical films of each embodiment of the present application were tested under the same test conditions for performance comparison.

[0109] The specific conversion rate changes under different exposure times are listed in Table 5.

[0110] Table 5

[0111]

[0112] It can be seen from the data in Table 5 that under blue light, the conversion rates of the optical films of Examples 1-3 after exposure for 10 seconds are all above 40%, and the conversion rates after exposure for 30 seconds are all above 100%. Relative to the optical film of Comparative Example 1, the polymerization rates after 10 seconds and 30 seconds can be increased by more than 40%, and some can be increased by 60% or more. Under green light, the conversion rates of the optical films of Examples 1-3 after exposure for 10 seconds are all above 30%, and the conversion rates after exposure for 30 seconds are all above 70%. Relative to the optical film of Comparative Example 1, the polymerization rate after exposure for 10 seconds can be increased by about 80%, and the polymerization rate after exposure for 30 seconds can be increased by more than 30%. Under red light, the conversion rates of the optical films of Examples 1-3 after exposure for 10 seconds are all above 45%, and the conversion rates after exposure for 30 seconds are all above 90%. Relative to the optical film of Comparative Example 1, the polymerization rate after exposure for 10 seconds can be increased by 100%, and the polymerization rate after exposure for 30 seconds is also effectively improved. It can be seen that the introduction of a second initiator can significantly help increase the polymerization rate.

[0113] Figure 6 These are transmittance test graphs of the sample films of various embodiments and comparative examples after being directly exposed without heating. Figure 7 The following are test diagrams of light transmittance of the sample films of each embodiment and comparative example after being heated and then exposed. Figure 6 and Figure 7 As shown, the optical films directly exposed without heating have better stability than those in Comparative Example 1, and the light transmittance does not change significantly.

[0114] The specific transmittance change values ​​of the optical films of various embodiments and comparative examples are listed in Table 6, where the increase is relative to that of Comparative Example 1.

[0115] Table 6

[0116]

[0117]

[0118] The data in Table 6 demonstrates that, regardless of whether or not heat treatment was performed, Examples 1-3 exhibit at least a 30% increase in diffraction efficiency compared to Comparative Example 1, indicating that the introduction of a second initiator can help improve diffraction efficiency during exposure. This is likely due to the improved polymerization rate of the optical film material in the R / G / B bands, meaning that the introduction of a second initiator can help enhance the material's photosensitivity.

[0119] Based on the same technical purpose, an embodiment of the present application also provides an electronic device, such as AR glasses, a vehicle-mounted head-up display device, etc. Figure 9FIG. 1 is a schematic diagram of the structure of AR glasses according to an embodiment. Figure 9 As shown, the AR glasses may include lenses, and an optical film according to an embodiment of the present application may be sandwiched between two lenses. After exposure, the optical film may become a holographic optical element that records all light information and enables 3D stereoscopic projection. Combined with the high light transmittance of the optical film, it can achieve a mutual combination of virtual and real life. Figure 10 FIG. 1 is a structural diagram of a vehicle head-up display device according to an embodiment of the present invention. Figure 10 As shown, the optical film material of the embodiment of the present application can be attached to the surface of the front windshield panel in the car, and vehicle information can be displayed through projection.

[0120] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An optical film material, characterized in that: The invention comprises a film-forming resin, a polymerizable monomer, a photosensitizer, a first initiator and a second initiator. The photosensitizer can generate photosensitive free radicals through reduction. The oxidation potential of the first initiator is greater than the reduction potential of the second initiator and is greater than the oxidation potential of the photosensitive free radicals.

2. The optical film material according to claim 1, characterized in that The oxidation potential of the first initiator is 0.2V to 2V.

3. The optical film material according to claim 1 or 2, characterized in that: The reduction potential of the second initiator is -1.2V to 0.4V.

4. The optical film material according to any one of claims 1 to 3, characterized in that: The oxidation potential of the photosensitive free radical is -0.2 to -0.01V.

5. The optical film material according to any one of claims 1 to 4, characterized in that: The mass proportion of the photosensitizer in the optical film material is 0.001 to 0.5%.

6. The optical film material according to any one of claims 1 to 5, characterized in that: The mass proportion of the first initiator in the optical film material is 0.1 to 10%.

7. The optical film material according to any one of claims 1 to 6, characterized in that: The mass proportion of the second initiator in the optical film material is 0.05-3%.

8. The optical film material according to any one of claims 1 to 7, characterized in that: The first initiator is selected from at least one of alkyl aryl ammonium borate, secondary aliphatic, secondary aromatic amines, tertiary aliphatic, and tertiary aromatic amines.

9. The optical film material according to any one of claims 1 to 8, characterized in that: The second initiator is at least one selected from iodonium salts, sulfonium salts, pyridinium salts, diazonium salts, persulfates, benzoyl peroxides, and compounds having alkyl free radicals.

10. The optical film material according to any one of claims 1 to 9, characterized in that: The photosensitizer is selected from at least one of anthocyanin, coumarin, dibenzopyrazine, phenothiazine, phenoxazine, pyrrole boron, and triarylmethane compounds.

11. The optical film material according to any one of claims 1 to 10, characterized in that: After the optical film is heat treated at 110-150° C. for 30-120 min, in the ultraviolet absorbance test, the absorbance change value T at a wavelength of 460 nm is 460 ≤10%, absorbance change value T at 532nm wavelength 532 ≤10%, absorbance change value T at 640nm wavelength 640 ≤40%.

12. The optical film material according to any one of claims 1 to 11, characterized in that: After the optical film material is heat-treated at 110-150° C. for 30-120 minutes, the double bond conversion rate in the molecular structure of the optical film material is ≤15%.

13. The optical film material according to any one of claims 1 to 12, characterized in that: After the optical film material is heat-treated at 110-150° C. for 30-120 minutes, the haze of the optical film material is ≤4%.

14. The optical film according to any one of claims 1 to 13, characterized in that: After the optical film is exposed to ultraviolet-visible light, the absorbance change value T at a wavelength of 460nm in the ultraviolet absorbance test is 460 ≤5%, absorbance change value T at 532nm wavelength 532 ≤5%, absorbance change value T at 640nm wavelength 640 ≤20%.

15. A display device, characterized in that: A substrate and an optical film material according to any one of claims 1 to 14 arranged on the substrate.

Images