Metal wire grid polaroid and preparation method and application thereof

Abstract

The invention provides a metal wire grid polaroid and a preparation method and application thereof. The preparation method comprises the following steps: (1) coating a curing adhesive on a base material, performing nano-imprinting and curing by using a silicon wafer mold with a microstructure, and separating the silicon wafer mold with the microstructure to obtain a base material with a micro-nano structure; and (2) pre-baking the base material with the micro-nano structure obtained in the step (1), transferring the base material into a magnetron sputtering cavity, and depositing metal on the surface of the base material with the micro-nano structure through a double-target magnetron sputtering process to obtain the metal wire grid polaroid. According to the invention, the micro-nano grating structure is manufactured by using a nanoimprint process, and the metal layer is sputtered on the surface of the grating structure by using double-target magnetron sputtering, so that an optical effect is realized; the preparation method of the metal wire grid polarizer provided by the invention has the characteristics of rapidness, high efficiency and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of polarizing elements, and in particular relates to a metal wire grid polarizer and a preparation method and application thereof. Background Art

[0002] Metal wire grid polarizer is a kind of polarizer that can provide polarized reflection performance. Different from the polarizer stretched by traditional chemical materials, the manufacturing and development difficulty of metal wire grid polarizer is more inclined to semiconductor process, and the requirements for equipment precision and material flatness are higher. At the same time, it can provide a polarization effect different from traditional absorption polarizer.

[0003] Metal wire grid polarizers can be used in new display fields such as infrared cameras, detection lenses, VR / AR optical paths, and are key optical devices in the above devices. The main reason why metal wire grid polarizers can achieve polarized reflection is that metal wire grid polarizers have extremely fine nano-metal wires on the surface of the substrate. The array structure composed of these metal wires can reflect polarized light parallel to the array direction and transmit polarized light perpendicular to the array direction. It is a device that uses micro-nano structures to achieve optical effects.

[0004] At present, there are many different processes in the production of metal wire grid polarizers, and the main differences are the production of microstructures and the production of metal wires. CN101432113A discloses a method for manufacturing an optical film with a concave-convex structure, an optical film, a wire grid polarization component and a phase difference film. The method for manufacturing an optical film with a concave-convex structure includes the steps of coating a solution in which a first resin is dissolved in a solvent on an annular belt or a roller-shaped mold with a concave-convex structure, and forming a resin solution layer on the mold; this solution requires specific development of the resin coating liquid, and the development of polymer materials often has a long cycle and a high development threshold.

[0005] CN101622557A discloses a polarizing plate and a liquid crystal display device using the polarizing plate. The polarizing plate is a polarizing plate having a substrate, a plurality of linear metal layers arranged at set intervals, and a plurality of linear black layers arranged at set intervals, wherein at least one of the plurality of linear metal layers and the plurality of linear black layers is arranged on the substrate. The black layer in the scheme affects the optical effect, and the black layer has the property of absorbing light, so that the metal wire grid polarizing plate prepared by the scheme cannot be used in display applications.

[0006] CN102289020A discloses a polarizing element and a manufacturing method thereof, a liquid crystal device, and an electronic device. The polarizing element comprises a substrate and a plurality of metal layers, the plurality of metal layers are arranged in stripes on one side of the substrate, and have a first dielectric layer and a second dielectric layer. This solution requires depositing a plurality of metal layers on the substrate, and the process is relatively complicated.

[0007] In the prior art, although the manufacture of metal wire grid polarizers can be realized, the manufacturing cost is high and the process is relatively complicated. Therefore, how to provide a method for preparing a metal wire grid polarizer with a simple process and low manufacturing cost has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a metal wire grid polarizer and a preparation method and application thereof. In the present invention, a micro-nano grating structure is manufactured by using a nanoimprinting process, and a metal layer is sputtered on the surface of the grating structure by using a dual-target magnetron sputtering, thereby achieving an optical effect. The preparation method of the metal wire grid polarizer provided by the present invention is characterized by being fast, efficient and low-cost.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a metal wire grid polarizer, the method comprising the following steps:

[0011] (1) coating a curing adhesive on a substrate, performing nanoimprinting using a silicon wafer mold with a microstructure, curing, and separating the silicon wafer mold with the microstructure to obtain a substrate with a micro-nano structure;

[0012] (2) After pre-baking the substrate with the micro-nano structure obtained in step (1), it is transferred to a magnetron sputtering chamber, and metal is deposited on the surface of the substrate with the micro-nano structure through a dual-target magnetron sputtering process to obtain the metal wire grid polarizer.

[0013] In the present invention, a micro-nano grating structure is fabricated by using a nanoimprinting process, and a metal layer is sputtered on the surface of the grating structure by using a dual-target magnetron sputtering process, thereby achieving an optical effect. The preparation method of the metal wire grid polarizer provided by the present invention is characterized by being fast, efficient, and low-cost.

[0014] If a single target is used to deposit metal twice, the interface state of the two metal depositions is different, and different crystal phases are easily grown. However, the present invention uses dual-target magnetron sputtering to simultaneously sputter a metal layer on the surface of the grating structure, so that the metal wraps the entire grating and tries not to deposit metal between the gratings.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0016] As a preferred technical solution of the present invention, in the dual-target magnetron sputtering process, two aluminum metal targets are placed symmetrically.

[0017] Preferably, the target material angle in the dual-target magnetron sputtering process is 10° to 45° (for example, it can be 10°, 12°, 15°, 18°, 20°, 23°, 25°, 27°, 30°, 33°, 36°, 39°, 42° or 45°, etc.), and more preferably 15°.

[0018] In the present invention, the target angle refers to the acute angle between the target and the vertical direction.

[0019] In the present invention, by controlling the target angle within a specific range, a metal wire grid polarizer with excellent performance can be prepared. If the target angle is too small or too large, the possibility of metal deposition between the gratings will increase.

[0020] Preferably, the target-substrate distance in the dual-target magnetron sputtering process is 70 to 90 mm (for example, it can be 70 mm, 72 mm, 74 mm, 76 mm, 78 mm, 80 mm, 82 mm, 84 mm, 86 mm, 88 mm or 90 mm, etc.), and more preferably 80 mm.

[0021] In the present invention, the target-substrate distance refers to the distance between the magnetron sputtering target and the substrate.

[0022] In the present invention, by controlling the target-substrate distance within a specific range, a metal wire grid polarizer with excellent performance can be prepared. If the target-substrate distance is too large, scattering and other phenomena are likely to occur, increasing the possibility of metal deposition between gratings; if the target-substrate distance is too small, the local temperature rises too high, which is likely to cause deformation of the polymer substrate.

[0023] As a preferred technical solution of the present invention, the sputtering power in the dual-target magnetron sputtering process is 20-40W, for example, it can be 20W, 22W, 24W, 26W, 28W, 30W, 32W, 34W, 36W, 38W or 40W.

[0024] Preferably, the sputtering time in the dual-target magnetron sputtering process is 180 to 220 s, for example, it may be 180 s, 185 s, 190 s, 195 s, 200 s, 205 s, 210 s, 215 s or 220 s.

[0025] If the sputtering power is a constant, the longer the sputtering time, the thicker the deposited metal layer; if the sputtering time is a constant, the greater the sputtering power, the thicker the deposited metal layer.

[0026] In the present invention, by controlling the sputtering power and sputtering time within a specific range, a metal layer with a specific thickness can be prepared, thereby obtaining a metal wire grid polarizer with excellent performance. If the sputtering power is too large, higher heat will be generated locally, and the polymer substrate itself is not heat-resistant, which will cause the polymer substrate to be damaged and the metal wire grid polarizer cannot be prepared; if the sputtering power is too small, the plasma may not be able to ignite normally, or the metal cannot be sputtered normally after ignition. Therefore, it is necessary to reasonably control the power to ensure both smooth completion of thin film deposition and low temperature.

[0027] As a preferred technical solution of the present invention, the substrate is selected from a polymer resin film or optical glass.

[0028] Preferably, the elastic modulus of the polymer resin film is 3000-4000 MPa, for example, it may be 3000 MPa, 3100 MPa, 3200 MPa, 3300 MPa, 3400 MPa, 3500 MPa, 3600 MPa, 3700 MPa, 3800 MPa, 3900 MPa or 4000 MPa.

[0029] Test method for elastic modulus: Test according to national standard GB / T 5594.2.

[0030] Preferably, the water contact angle of the polymer resin film is 50° to 80°, for example, it may be 50°, 52°, 54°, 56°, 58°, 60°, 63°, 66°, 68°, 70°, 72°, 75°, 78° or 80°.

[0031] The water contact angle of the polymer resin film was tested using a water contact angle tester.

[0032] Preferably, the glass transition temperature of the polymer resin film is ≥100°C, for example, it may be 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, 123°C or 125°C.

[0033] Test method for glass transition temperature: It can be tested according to the national standard GB / T 29611-2013.

[0034] Preferably, the polymer resin film is selected from any one of triacetyl cellulose (TAC) film, acrylic (PMMA) film, and polyethylene terephthalate (PET) film.

[0035] It should be noted that the present invention does not have any special restrictions on the thickness of the substrate, and those skilled in the art may determine it according to the product usage scenario, and illustratively includes: the thickness used in the optical path is 150 μm.

[0036] As a preferred technical solution of the present invention, the periodic size of the silicon wafer mold with microstructure is ≤200nm, for example, it can be 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm.

[0037] Preferably, the curing adhesive comprises UV light curing adhesive.

[0038] It should be noted that in the present invention, there is no special restriction on the specific selection of UV light-curing adhesive, and any UV light-curing adhesive commonly used in the art is applicable.

[0039] Preferably, the coating has a thickness of 100 to 300 nm (for example, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm, 220 nm, 240 nm, 260 nm, 280 nm or 300 nm, etc.), and more preferably 150 nm.

[0040] Preferably, the coating method comprises spin coating.

[0041] Preferably, the spin coating rotation speed is 2500-4500 rpm (for example, it can be 2500 rpm, 2700 rpm, 2800 rpm, 3000 rpm, 3200 rpm, 3400 rpm, 3600 rpm, 3800 rpm, 4000 rpm, 4200 rpm, 4300 rpm or 4500 rpm, etc.), and more preferably 3000 rpm.

[0042] As a preferred technical solution of the present invention, the nanoimprinting time is ≥15s, for example, it can be 15s, 16s, 17s, 18s, 19s, 20s, 21s, 22s, 23s, 24s or 25s.

[0043] Preferably, the curing method comprises curing using UV light.

[0044] As a preferred technical solution of the present invention, the pre-baking temperature is 55-85°C, for example, it can be 55°C, 56°C, 58°C, 60°C, 63°C, 66°C, 68°C, 70°C, 72°C, 75°C, 77°C, 78°C, 80°C, 81°C, 84°C or 85°C, etc.

[0045] In the present invention, the role of pre-baking is to remove the water vapor adsorbed in the substrate and keep the sample components pure.

[0046] Preferably, the pre-baking time is ≥45 min, for example, it can be 45 min, 46 min, 47 min, 48 min, 49 min, 50 min, 51 min, 52 min, 53 min, 54 min or 55 min, etc.

[0047] As a preferred technical solution of the present invention, the method for preparing the metal wire grid polarizer specifically comprises the following steps:

[0048] (1) Spin-coating a UV light-curing adhesive on a substrate at a rotation speed of 2500 to 4500 rpm to a thickness of 100 to 300 nm, performing nanoimprinting using a silicon wafer mold with a microstructure, curing using UV light, and separating the silicon wafer mold with a microstructure to obtain a substrate with a micro-nano structure;

[0049] Among them, the periodic size in the silicon wafer mold with microstructures is ≤200nm, and the nanoimprinting time is ≥15s;

[0050] (2) pre-baking the substrate with micro-nano structure obtained in step (1) at 55-85° C. for a pre-baking time of ≥45 min, transferring it to a magnetron sputtering chamber, and depositing metal on the surface of the substrate with micro-nano structure through a dual-target magnetron sputtering process to obtain the metal wire grid polarizer;

[0051] Among them, in the dual-target magnetron sputtering process, two aluminum metal targets are placed symmetrically, the target angle is 10°~45°, the target-substrate distance is 70~90mm, the sputtering power is 20~40W, and the sputtering time is 180~220s.

[0052] It should be noted that the transfer of the pre-baked substrate with micro-nano structure to the magnetron sputtering chamber needs to be carried out under vacuum conditions, and after the transfer, the vacuum degree of the magnetron sputtering chamber reaches 10 -5 Pa, inert gas (argon is preferred) is introduced. When the pressure inside the chamber stabilizes at 10 -3 After Pa, the target surface can be stably ignited.

[0053] In a second aspect, the present invention provides a metal wire grid polarizer prepared by the preparation method described in the first aspect, wherein the optical transmittance of the metal wire grid polarizer at a wavelength ≥430nm is ≥60%, for example, it can be 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78% or 80%, etc.

[0054] The optical transmittance test method uses JASCO spectrophotometer V7100 for testing, and the spectral range is visible light 380nm ~ 780nm.

[0055] In a third aspect, the present invention provides an application of the metal wire grid polarizer as described in the second aspect, wherein the metal wire grid polarizer is used to prepare an imaging device or a detection device.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention manufactures a micro-nano grating structure by using a nanoimprinting process, sputters a metal layer on the surface of the grating structure by using dual-target magnetron sputtering, and simultaneously controls various process conditions of the dual-target magnetron sputtering within a specific range, thereby obtaining a metal wire grid polarizer with excellent performance through a simple, fast and efficient preparation method. The metal wire grid polarizer has an optical transmittance of ≥60% within the visible light range of a wavelength ≥430nm, and no metal is deposited between the gratings. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic diagram of the preparation process of the metal wire grid polarizer provided in Example 1 of the present invention;

[0059] Figure 2 is a positional relationship diagram of the aluminum metal target and the sample stage in the dual-target magnetron sputtering in Example 1 of the present invention;

[0060] Figure 3 is a microscopic morphology image of the metal wire grid polarizer provided in Example 1 of the present invention;

[0061] Figure 4 is a microscopic morphology image of the metal wire grid polarizer provided by Example 2 of the present invention;

[0062] Figure 5 This is a microscopic morphology of the metal wire grid polarizer provided in Comparative Example 1 of the present invention;

[0063] Figure 6 It is a light transmittance curve diagram of the metal wire grid polarizer provided in Examples 1-2 and Comparative Example 1 of the present invention under different wavelengths of light. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0065] It should be noted that in the following examples and comparative examples, the UV light-curing adhesive used is a commercially available acrylic resin adhesive.

[0066] The dual-target magnetron sputtering coating equipment is DSC300.

[0067] Example 1

[0068] This embodiment provides a metal wire grid polarizer and a method for preparing the same. The schematic diagram of the preparation process of the preparation method is as follows: Figure 1 As shown, the details are as follows:

[0069] (1) Spin-coating a UV light-curing adhesive on a substrate at a rotation speed of 3000 rpm to a thickness of 150 nm, performing nanoimprinting using a silicon wafer mold with a microstructure, curing using UV light, and separating the silicon wafer template with a microstructure to obtain a substrate with a micro-nano structure;

[0070] Among them, the periodic size of the silicon wafer mold with microstructures is 200nm, and the nanoimprinting time is 20s;

[0071] (2) pre-baking the substrate with micro-nano structure obtained in step (1) at 60° C. for 50 min, transferring it to a magnetron sputtering chamber, and depositing metal on the surface of the substrate with micro-nano structure by a dual-target magnetron sputtering process to obtain the metal wire grid polarizer;

[0072] In the dual-target magnetron sputtering process, two aluminum metal targets are placed symmetrically, the target angle is 15°, the target-substrate distance is 80 mm, the sputtering power is 25 W, and the sputtering time is 200 s. The position relationship between the aluminum metal target and the sample stage in the dual-target magnetron sputtering process is as follows: Figure 2 shown.

[0073] Example 2

[0074] This embodiment provides a metal wire grid polarizer and a preparation method thereof, which is different from Embodiment 1 only in that the sputtering power in the dual-target magnetron sputtering process is 25 W, the sputtering time is 160 s, and other conditions are the same as those in Embodiment 1.

[0075] Comparative Example 1

[0076] This comparative example provides a metal wire grid polarizer and a preparation method thereof, which is different from Example 1 only in that the sputtering power in the dual-target magnetron sputtering process is 80 W, the sputtering time is 200 s, and other conditions are the same as Example 1.

[0077] Hitachi SU8010 scanning electron microscope was used to characterize the end surface morphology of the metal wire grid polarizers prepared in Examples 1-2 and Comparative Example 1. The characterization results are as follows: Figure 3-5 As shown. Figure 3-5 It can be seen that the micro-nano grating structure was successfully prepared in Examples 1-2, but since the sputtering power in Comparative Example 1 was too large, metal deposition occurred between the gratings in the prepared micro-nano grating structure.

[0078] The optical transmittance of the metal wire grid polarizers provided in the above embodiments and comparative examples was tested, and the specific testing method is as follows:

[0079] The optical transmittance of the metal wire grid polarizers provided in Examples 1-2 and Comparative Example 1 was tested using a JASCO spectrophotometer V7100, with the spectral range being visible light 380nm to 780nm. The test results are as follows: Figure 6 As shown. Figure 6 It can be seen that the metal wire grid polarizer provided by Examples 1-2 of the present invention has an optical transmittance of ≥60% when the wavelength is ≥430nm.

[0080] From the above content, it can be seen that the present invention uses a nanoimprint process to produce a micro-nano grating structure, and uses dual-target magnetron sputtering to sputter a metal layer on the surface of the grating structure. At the same time, by controlling the various process conditions of the dual-target magnetron sputtering within a specific range, a simple, fast and efficient preparation method is used to prepare a metal wire grid polarizer with excellent performance. The optical transmittance of the polarizer is ≥60% in the visible light range with a wavelength ≥430nm, and no metal is deposited between the gratings.

[0081] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a metal wire grid polarizer, characterized in that: The preparation method comprises the following steps: (1) coating a curing adhesive on a substrate, performing nanoimprinting using a silicon wafer mold with a microstructure, curing, and separating the silicon wafer mold with the microstructure to obtain a substrate with a micro-nano structure; (2) After pre-baking the substrate with the micro-nano structure obtained in step (1), it is transferred to a magnetron sputtering chamber, and metal is deposited on the surface of the substrate with the micro-nano structure through a dual-target magnetron sputtering process to obtain the metal wire grid polarizer.

2. The preparation method according to claim 1, characterized in that: In the dual-target magnetron sputtering process, two aluminum metal targets are placed symmetrically; Preferably, the target angle in the dual-target magnetron sputtering process is 10° to 45°; Preferably, the target-substrate distance in the dual-target magnetron sputtering process is 70-90 mm.

3. The preparation method according to claim 1, characterized in that: The sputtering power in the dual-target magnetron sputtering process is 20 to 40 W; Preferably, the sputtering time in the dual-target magnetron sputtering process is 180 to 220 seconds.

4. The preparation method according to claim 1, characterized in that: The substrate is selected from a polymer resin film or optical glass; Preferably, the elastic modulus of the polymer resin film is 3000-4000 MPa; Preferably, the water contact angle of the polymer resin film is 50° to 80°; Preferably, the glass transition temperature of the polymer resin film is ≥100°C; Preferably, the polymer resin film is selected from any one of triacetyl cellulose film, acrylic film and polyethylene terephthalate film.

5. The preparation method according to claim 1, characterized in that: The periodic size of the silicon wafer mold with microstructure is ≤200nm; Preferably, the curing adhesive comprises UV light curing adhesive; Preferably, the coating thickness is 100 to 300 nm; Preferably, the coating method comprises spin coating; Preferably, the spin coating has a rotation speed of 2500-4500 rpm.

6. The preparation method according to claim 1, characterized in that: The nanoimprinting time is ≥ 15 s; Preferably, the curing method comprises curing using UV light.

7. The preparation method according to claim 1, characterized in that: The pre-baking temperature is 55-85°C; Preferably, the pre-baking time is ≥45 min.

8. The preparation method according to claim 1, characterized in that: The method for preparing the metal wire grid polarizer specifically comprises the following steps: (1) Spin-coating a UV light-curing adhesive on a substrate at a rotation speed of 2500 to 4500 rpm to a thickness of 100 to 300 nm, performing nanoimprinting using a silicon wafer mold with a microstructure, curing using UV light, and separating the silicon wafer mold with a microstructure to obtain a substrate with a micro-nano structure; Among them, the periodic size in the silicon wafer mold with microstructures is ≤200nm, and the nanoimprinting time is ≥15s; (2) pre-baking the substrate with micro-nano structure obtained in step (1) at 55-85° C. for a pre-baking time of ≥45 min, transferring it to a magnetron sputtering chamber, and depositing metal on the surface of the substrate with micro-nano structure through a dual-target magnetron sputtering process to obtain the metal wire grid polarizer; Among them, in the dual-target magnetron sputtering process, two aluminum metal targets are placed symmetrically, the target angle is 10°~45°, the target-substrate distance is 70~90mm, the sputtering power is 20~40W, and the sputtering time is 180~220s.

9. A metal wire grid polarizer prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The optical transmittance of the metal wire grid polarizer is ≥60% at a wavelength ≥430 nm.

10. An application of the metal wire grid polarizer according to claim 9, characterized in that: The metal wire grid polarizer is used for preparing imaging equipment or detection equipment.

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