Black optical films and optical products

Abstract

The present application relates to a black optical film and an optical product. The black optical film has an inner layer close to the optical product and an outer layer far from the optical product. The black optical film includes an organic matting layer, a high refractive index layer and a low refractive index layer alternately stacked, and the outer layer is provided with an organic matting layer; the organic matting layer is made of an organic matting material, and the organic matting material includes an organic component and an inorganic component, and the organic component includes polyarylate, amorphous copolyester and epoxy oligomer, and the inorganic component includes Ti element, Mg element and O element, and Fe element and / or Co element; the high refractive index layer is made of a high refractive index material, and the high refractive index material includes Nb2O5 and Al2O3; the low refractive index layer is made of a low refractive index material, and the low refractive index material is selected from any one or more of SiO2, MgF2 or a silicon-aluminum mixture. The black optical film of the present application has the dual effects of transmissive matting and reflective matting, is non-conductive, and has excellent chemical resistance and scratch resistance.

Description

Technical Field

[0001] The present application relates to a black optical film and an optical product, belonging to the field of coating materials. Background Art

[0002] As mobile phone lens modules develop towards high pixels, large apertures, and ultra-thinness, consumers have higher and higher requirements for the imaging quality of camera modules. However, there are some problems with the existing black coating materials when preparing black films, which limits the application of black films prepared by vacuum evaporation coating processes in the direction of optical extinction. This is because current black coating materials are often composed of one or more metal or semiconductor materials. This is because metal or semiconductor materials have a wide conduction band. It can absorb light with a wide range of wavelengths to form extinction. However, due to the presence of a large number of free electrons in metal materials or semiconductors, these free electrons cause a wide spectrum of uniform reflection on the surface of the material, which causes strong surface reflection that is difficult to avoid. Although this type of black film material can absorb transmitted light by increasing the extinction coefficient, it is basically powerless against reflected light. Especially on smooth surfaces, the surface after coating often presents a mirror-like effect.

[0003] Chinese patent CN2021113014089 discloses a coating composition, a preparation method thereof, a matte film, a lens module, and a terminal. The material has a strong absorption effect in the visible light and near-infrared bands, and the material can be used to prepare a black matte film with both transmissive and reflective matte effects. However, the applicant found that the film formed by the material has a certain conductive effect, and its chemical resistance and scratch resistance are weak, and it cannot be used on electronic devices under specific environments.

[0004] Based on this, the applicant optimized the composition ingredients and provided a new film product. Summary of the invention

[0005] The purpose of the present application is to provide a black optical film and an optical product, which has the dual effects of transmissive extinction and reflective extinction, is non-conductive and has excellent chemical resistance and scratch resistance.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a black optical film having an inner layer close to an optical product and an outer layer far from the optical product, the black optical film comprising an organic matte layer, a high refractive index layer and a low refractive index layer alternately stacked, the outer layer being provided with the organic matte layer;

[0008] The organic matting layer is made of an organic matting material, which includes an organic component and an inorganic component, wherein the organic component includes polyarylate, amorphous copolyester and epoxy oligomer, and the inorganic component includes Ti element, Mg element and O element, and Fe element and / or Co element;

[0009] The high refractive index layer is made of a high refractive index material, and the high refractive index material includes Nb2O5 and Al2O3;

[0010] The low refractive index layer is made of a low refractive index material, and the low refractive index material is selected from any one or more of SiO2, MgF2 or a silicon-aluminum mixture.

[0011] As one possible implementation manner, the high refractive index material further includes CaO and graphite powder.

[0012] As one of the possible implementations, when the number of layers of the black optical film is less than 8, at least one layer of the organic matte layer is provided.

[0013] As one possible implementation manner, when the number of layers of the black optical film is greater than or equal to 8, at least two organic matt layers are provided, and at least one high refractive index layer and / or low refractive index layer is provided between the two organic matt layers.

[0014] As one possible implementation manner, the organic component further includes PMMA, and the organic matte layer is formed by mixing the inorganic component with a resin binder made from the organic component.

[0015] As one possible embodiment, in the inorganic component, the Ti element is selected from at least one of Ti, TiO2, Ti2O3 or Ti3O5; and / or, the Mg element is selected from MgO; and / or, the Fe element is selected from at least one of Fe2O3 or FeO; and / or, the Co element is selected from at least one of Co2O3 or CoO.

[0016] As one of the possible implementation modes, in the high refractive index layer, the mass contents of Nb2O5, Al2O3, CaO and graphite powder are 60% to 70%, 17% to 27%, 1% to 3% and 5% to 10% respectively.

[0017] In a second aspect, the present application provides an optical product, which includes the black optical film described in the first aspect.

[0018] As one possible implementation manner, the optical product is a filter.

[0019] As one possible implementation manner, the black optical film is arranged on the surface of the optical product, the outer layer is an organic matte layer, the high refractive index layer and the low refractive index layer are alternately stacked between the outer layer and the optical product, or the high refractive index layer, the low refractive index layer and the organic matte layer are alternately stacked.

[0020] Through the embodiments disclosed in the present application, the black optical film of the present application has the dual effects of transmittance extinction and reflective extinction. At the same time, while maintaining good bonding strength, adhesion, chemical resistance and scratch resistance, it has high overall insulation properties and can be used on electronic devices in specific environments.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. 1 is a light transmission and reflection curve diagram of a black optical film according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] It should be noted that the terms “upper”, “lower”, “left”, “right”, “inner”, “outer”, etc. in the present invention are only used to illustrate the present invention with reference to the drawings and are not intended to be limiting terms.

[0025] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units that are inherent to these processes, methods, products or devices. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0026] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0027] On the one hand, the present application provides a black optical film, which has an inner layer close to the optical product and an outer layer away from the optical product. The black optical film includes organic matte layers, high refractive index layers and low refractive index layers that are alternately stacked, and the outer layer is provided with the organic matte layer.

[0028] Wherein, the organic matting layer is made of an organic matting material, the organic matting material includes an organic component and an inorganic component, the organic component includes polyarylate, amorphous copolyester and epoxy oligomer, and the inorganic component includes Ti element, Mg element and O element, as well as Fe element and / or Co element. The high refractive index layer is made of a high refractive index material, the high refractive index material includes Nb2O5 and Al2O3. The low refractive index layer is made of a low refractive index material, the low refractive index material is selected from any one or more of SiO2, MgF2 or a silicon-aluminum mixture.

[0029] Optionally, the high refractive index material also includes CaO and graphite powder. Compared with the high refractive index layer without addition, the inventors found that by adding CaO and graphite powder, on the one hand, the blackness of the high refractive index layer can be increased as black materials, and on the other hand, its insulation can be increased. At the same time, the inventors unexpectedly found that the high refractive index materials Nb2O5, Al2O3, CaO and graphite powder can improve the firmness, adhesion and scratch resistance of the high refractive index layer by using a special mass content. At the same time, the surface of the formed high refractive index layer is smooth and flat, and it is easy to carry out coating, evaporation and other processes on its surface.

[0030] In order to ensure the overall strength of the black optical film, as an example but not a limitation, when the number of layers of the black optical film is less than 8, at least one organic matting layer is provided. As an example but not a limitation, when the number of layers of the black optical film is greater than or equal to 8, at least two organic matting layers are provided, and at least one high refractive index layer and / or low refractive index layer is provided between the two organic matting layers.

[0031] Optionally, the organic component further includes PMMA, and the organic matte layer is formed by mixing the inorganic component with the organic component as a resin binder. The inventors have found that the scratch resistance, tensile strength and impact resistance of the organic matte layer can be improved by adding PMMA, and its content in the organic component should not exceed 3wt%.

[0032] As an example but not a limitation, in the inorganic component, the Ti element is selected from at least one of Ti, TiO2, Ti2O3 or Ti3O5.

[0033] As an example but not a limitation, the Mg element is selected from MgO.

[0034] As an example but not a limitation, the Fe element is selected from at least one of Fe2O3 or FeO.

[0035] As an example but not a limitation, the Co element is selected from at least one of Co2O3 or CoO.

[0036] As an example but not a limitation, in the high refractive index layer, the mass contents of Nb2O5, Al2O3, CaO and graphite powder are 60% to 70%, 17% to 27%, 1% to 3% and 5% to 10% respectively.

[0037] The above-mentioned black optical film can be applied to the optical product structure of electronic devices. Based on this, the present application also provides an optical product, on the surface of which the above-mentioned black optical film is arranged.

[0038] By way of example and not limitation, the optical product is a filter.

[0039] As an example but not a limitation, the black optical film is disposed on the surface of the optical product, the outer layer is an organic matte layer, and the high refractive index layer and the low refractive index layer are alternately stacked between the outer layer and the optical product, or the high refractive index layer, the low refractive index layer and the organic matte layer are alternately stacked. Preferably, the outermost layer is an organic matte layer, the second outermost layer is a high refractive index layer, and then the low refractive index layer and the high refractive index layer can be alternately stacked; at the same time, the side and edge of the layered structure are also provided with an organic matte layer.

[0040] As an example but not a limitation, the high refractive index layer and the low refractive index layer can be formed by evaporation coating; the organic matte layer can be formed by coating or printing.

[0041] The applicant found that the matte film disclosed in Chinese patent CN2021113014089 is conductive and has weak chemical resistance. Specifically, the matte film is made into a strip sample and immersed in a household chemical test solution containing water, vinegar, soybean oil, orange juice and glycerin, and buffered to pH 8. After soaking for 4 hours, a tensile test was performed, and the results showed that its tensile retention rate was only 43%.

[0042] The present application will be further described in detail below in conjunction with specific embodiments.

[0043] Embodiment 1

[0044] Preparation of organic matting layer coating liquid / printing liquid

[0045] Weigh 10kg of raw materials in the proportion of Ti 17%, TiO2 50%, MgO 25%, and Fe2O3 8%, and use a ball mill or a strong mixer to evenly mix the above inorganic components. Then use a hydraulic press to press the mixed raw materials into blocks, break them into small particles, and sieve them. Then put the small particles into a graphite crucible. And put the crucible into a vacuum sintering furnace. Then increase the temperature to 900℃ at a rate of 10℃ per minute. Then heat the material to about 1500℃ at a rate of 3℃ per minute. Keep the temperature constant for more than 3 hours. After the reaction is completed, stop heating and let the material cool naturally.

[0046] The resin binder is prepared from polyarylate, amorphous copolyester and epoxy oligomer, wherein the epoxy oligomer is a compound having 5 epoxy groups and its content does not exceed 1wt% of the resin binder, thereby increasing the chemical resistance of the material.

[0047] The resin binder is dissolved in toluene, and the material prepared from the inorganic component is ground and added thereto to disperse or dissolve the material to prevent it from aggregating, thereby preparing a coating liquid or printing liquid for forming an organic matting layer. In this embodiment, the content of the inorganic component relative to the total organic matting material is 55wt%.

[0048] Preparation of high refractive index materials

[0049] According to the total weight of 10kg, the selected materials are weighed according to the weight ratio of Nb2O5:Al2O3:CaO:C=65%:25%:3%:7%, and sieved one by one into a stainless steel container. After manual mixing, sieve again. Repeat the mixing and sieving process several times until the materials are fully mixed. Weigh out 5%-10% of the total weight of the mixture of deionized water, and mix the water evenly into the mixture, and granulate the mixed materials by pressing granulation. Place the prepared granules in a crucible, use a vacuum electric furnace at 1000℃-1500℃ for 3-5 hours to remove moisture and preliminarily sinter. Place the sintered material in a smelting crucible, vacuum melt at 1600℃-1850℃, melt the material into a liquid state, and maintain for 3-5 hours. After the melt cools, take it out and crush it, and then sieve and package the obtained granules.

[0050] The low refractive index materials used in this embodiment are SiO2 and MgF2.

[0051] Formation of black optical film

[0052] Place high refractive index material, SiO2, and MgF2 in crucibles respectively, and load them into the model 1300 vacuum evaporation coating equipment. Load the plastic substrate into the coating equipment, close the vacuum chamber door of the equipment, and evacuate to the working vacuum.

[0053] After pre-melting the above materials, vacuum evaporation coating is performed. When forming a low refractive index layer, the coating process is set as follows: the initial evaporation vacuum degree is 3×10 -3 Pa, substrate temperature is room temperature, deposition rate is 5 angstroms / s, electron gun evaporation beam current is about 240 mA. A Hall ion source is used, ion source anode voltage is 200 V, current is 1 A, working medium is Ar, and gas flow rate is 10 sccm.

[0054] When forming the high refractive index layer, the process parameters are set as follows: the initial vacuum degree of the coating machine is set to 3x10 -3 Pa; Evaporation method: electron gun evaporation; Substrate temperature: 250°C; Evaporation rate: 3 -10 Angstrom / second; film density: 4.5g / cm 3 ; Evaporation temperature: 1700℃-1850℃

[0055] A SiO2 / high refractive index layer / MgF2 / high refractive index layer structure is formed on a plastic substrate, with a thickness of 42nm / 65nm / 68nm / 80nm.

[0056] Then, the organic matt layer coating liquid of this embodiment is coated on the outermost high refractive index layer by using a coating machine, and dried and cured at 80-110° C. to form an organic matt layer.

[0057] like Figure 1 As shown in the figure, after testing, the reflectivity of the black optical film formed in this embodiment in the visible light band of 350-700nm wavelength is less than 0.04%, and the light transmittance in the visible light band is generally less than 0.05%. At the same time, after using a four-probe instrument to test the square resistance of the film of this embodiment, and then measuring its thickness, the resistivity of the film of this embodiment is obtained. The resistivity of the black optical film of this embodiment is as high as 10 9 -10 12 Ω·cm.

[0058] The black optical film of this embodiment was made into a strip sample and immersed in a household chemical test solution containing water, vinegar, soybean oil, orange juice and glycerin, and the pH was buffered to 8. After immersion for 4 hours, a tensile test was performed, and the result showed that the tensile retention rate was 82%.

[0059] Embodiment 2

[0060] This embodiment is basically the same as the first embodiment, with the obvious difference being that the organic component in the organic matting layer of this embodiment further contains 1 wt % of PMMA.

[0061] After testing, it was found that the black optical film of this embodiment not only exhibited better chemical resistance (tensile retention rate exceeded 105%), but also had excellent scratch resistance:

[0062] Use a 1 / 4 inch (6.5mm), dry, clean cotton pad to scratch the surface of the coating 50 times, and the pressure during the test is not less than 1 pound (0.5 kg). The results show that there are no cracks or scratches on the surface of the film.

[0063] Furthermore, it was found that when the content of PMMA was increased, the tensile retention of the black optical film increased significantly. However, when the content of the organic component exceeded 3 wt%, it was found that the light transmittance of the film was increased (exceeding 1%).

[0064] Embodiment 3

[0065] This embodiment is basically the same as the first embodiment, with the obvious difference that the inorganic component in the organic matting layer of this embodiment also contains CoO, and the contents of Ti, TiO2, MgO, Fe2O3 and CoO are 17wt%, 50wt%, 25wt%, 4wt% and 4wt% respectively.

[0066] After testing, it was found that the reflectivity of the black optical film formed in this embodiment in the visible light band of 350-700 nm wavelength was lower than 0.1%, and the light transmittance in the visible light band was generally lower than 0.07%.

[0067] Embodiment 4

[0068] This embodiment is basically the same as the first embodiment, with the obvious difference being that the organic component in the organic matting layer of this embodiment further contains 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0069] After testing in an aging box, it was found that the black optical film of this embodiment also exhibited better weather resistance.

[0070] In summary: the black optical film of the present application has the dual effects of transmittance extinction and reflection extinction. At the same time, it has high overall insulation while maintaining good bonding strength, adhesion, chemical resistance and scratch resistance, and can be used on electronic devices in specific environments.

[0071] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A black optical film having an inner layer close to an optical product and an outer layer away from the optical product, characterized in that: The black optical film comprises an organic matte layer, a high refractive index layer and a low refractive index layer which are alternately stacked, and the outer layer is provided with the organic matte layer; The organic matting layer is made of an organic matting material, which includes an organic component and an inorganic component, wherein the organic component includes polyarylate, amorphous copolyester and epoxy oligomer, and the inorganic component includes Ti element, Mg element and O element, and Fe element and / or Co element; The high refractive index layer is made of a high refractive index material, and the high refractive index material includes Nb2O5 and Al2O3; The low refractive index layer is made of a low refractive index material, and the low refractive index material is selected from any one or more of SiO2, MgF2 or a silicon-aluminum mixture; The high refractive index material also includes CaO and graphite powder; In the inorganic component, the Ti element is selected from at least one of Ti, TiO2, Ti2O3 or Ti3O5; and / or the Mg element is selected from MgO; and / or the Fe element is selected from at least one of Fe2O3 or FeO; and / or the Co element is selected from at least one of Co2O3 or CoO; In the high refractive index layer, the mass contents of Nb2O5, Al2O3, CaO and graphite powder are 60% to 70%, 17% to 27%, 1% to 3% and 5% to 10% respectively.

2. The black optical film according to claim 1, characterized in that: When the number of the black optical film layers is less than 8, at least one organic matting layer is provided.

3. The black optical film according to claim 1, characterized in that: When the number of layers of the black optical film is greater than or equal to 8, at least two organic matt layers are provided, and at least one high refractive index layer and / or low refractive index layer is provided between the two organic matt layers.

4. The black optical film according to claim 1, characterized in that: The organic component further includes PMMA, and the organic matte layer is formed by mixing the inorganic component with a resin binder made from the organic component.

5. An optical product, characterized in that: The invention comprises the black optical film as claimed in any one of claims 1 to 4.

6. The optical product according to claim 5, characterized in that: The optical product is a filter.

7. The optical product according to claim 6, characterized in that: The black optical film is arranged on the surface of the optical product, the outer layer is an organic matte layer, and the high refractive index layer and the low refractive index layer are alternately stacked between the outer layer and the optical product, or the high refractive index layer, the low refractive index layer and the organic matte layer are alternately stacked.

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