Method for manufacturing optical member

Abstract

[Problem] To produce an optical member having a high anti-reflection effect in a high-temperature environment by forming a protective film on a fine uneven structure formed on the surface of a synthetic resin base material. [Solution] This method for manufacturing an optical member is provided with: a fine uneven structure formation step in which a fine uneven structure is formed on the surface of a substrate by changing the surface of the substrate by ion irradiation; and a protective film formation step for forming a protective film on the fine uneven structure formed on the surface of the substrate by evaporating the vapor deposition material on the surface of the substrate.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an optical component. For example, it can be applied to a method for manufacturing an optical component with a high antireflection effect in a high-temperature environment by forming a protective film on a fine concavo-convex structure formed on the surface of a plastic (synthetic resin) substrate. Background Art

[0002] Plastic with excellent light transmittance is particularly used as a substitute material for glass because of its light weight, high mechanical strength, good processability, and freedom of design. Especially in the optical field, plastic is widely used. In recent years, plastic has also been used in a wide range of components such as automotive headlamps.

[0003] Currently widely used transparent plastics include thermoplastic polyvinyl chloride (PVC: Polyvinyl Chloride), polystyrene (PS: Polystyrene), polycarbonate (PC: Polycarbonate), polymethyl methacrylate resin (PMMA: Poly Methyl Methacrylate), thermosetting polyethylene glycol diallyl carbonate (CR39), etc.

[0004] Among these plastic categories, PMMA is excellent in terms of transparency, light weight, processability, impact resistance, etc. as an optical component. In particular, its light transmittance is the best compared to other resins. Prior Art Documents Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 2019-15826 Summary of the Invention Problems to be Solved by the Invention

[0006] However, when forming an antireflection film for suppressing surface reflection on the surface of a PMMA substrate in order to improve the transmittance of an optical component using polymethyl methacrylate resin (PMMA), the following problems exist.

[0007] For example, in the optical field such as projectors for civilian equipment, reliability conditions of about 70 °C are required. Therefore, an antireflection film can be formed on the surface of a PMMA substrate by vacuum evaporation. On the other hand, the reliability conditions for the lighting system in the automotive field are high-temperature resistance of 90 to 100 °C (hereinafter, the high-temperature environment refers to an environment of about 90 to 100 °C). Therefore, there is a problem that cracks are generated in the formed antireflection film due to the difference in the linear expansion rate of the substrate and the linear expansion rate of the antireflection film.

[0008] In addition, the headlamps of automobiles initially used a single lens, but now multiple lenses with higher precision are required. When multiple lenses are used, since it is necessary to correct aberration, there is a problem that as the number of lenses increases, surface reflection also increases.

[0009] Therefore, in view of the above problems, the present invention provides a method for manufacturing an optical component with high anti-reflection effect in a high-temperature environment, which forms a protective film on a fine concavo-convex structure formed on the surface of a substrate of a synthetic resin such as polymethyl methacrylate resin, so as to have heat resistance and prevent light energy loss in a target high-temperature environment. Technical means for solving the problem

[0010] In order to solve the above problems, the manufacturing method of the optical component of the present invention includes: (1) a fine concavo-convex structure forming step, which changes the surface of the substrate by ion irradiation to form a fine concavo-convex structure on the surface of the substrate; (2) a protective film forming step, which evaporates a vapor deposition material and vapor-deposits it on the surface of the substrate to form a protective film on the fine concavo-convex structure formed on the surface of the substrate. Effects of the invention

[0011] According to the present invention, a protective film is formed on a fine concavo-convex structure formed on the surface of a synthetic resin substrate, so that an optical component with high anti-reflection effect in a high-temperature environment can be manufactured. Description of the drawings

[0012] Figure 1 It is a diagram showing the formation conditions of the fine concavo-convex structure of process A and the spectral characteristics of the substrate having the fine concavo-convex structure. Figure 2 It is a diagram showing the formation conditions of the fine concavo-convex structure of process C and the spectral characteristics of the substrate having the fine concavo-convex structure. Figure 3 It is a diagram showing the spectral characteristics of the substrate on which the fine concavo-convex structure and the protective film are formed in the process of Example 1. Figure 4 It is a diagram showing the spectral characteristics of the substrate on which the fine concavo-convex structure and the protective film are formed in the process of Example 2. Figure 5 It is a diagram showing the spectral characteristics of the substrate on which the fine concavo-convex structure and the protective film are formed in the process of Example 3. Figure 6 It is a diagram showing the spectral characteristics of the substrate on which the fine concavo-convex structure and the protective film are formed in the process of Example 4. Figure 7 It is a diagram showing the spectral characteristics of the substrate on which the fine concavo-convex structure and the protective film are formed in the process of Example 5. Figure 8It uses a substrate with a fine concavo-convex structure formed in Process A to show the spectroscopic characteristics of the substrate before the high-temperature test and the results of the spectroscopic characteristics of the substrate in a high-temperature environment. Figure 9 It uses the substrate of Example 1 to show the spectroscopic characteristics before the high-temperature test and the results of the spectroscopic characteristics in a high-temperature environment. Figure 10 It uses the substrate of Example 3 to show the spectroscopic characteristics before the high-temperature test and the results of the spectroscopic characteristics in a high-temperature environment. Figure 11 It is the comparison result of the antireflection effect between Example 1 and other antireflection films. Figure 12 It is a graph showing the spectroscopic characteristics of Example 1 and other antireflection films. Detailed implementation mode

[0013] (A) Implementation mode Hereinafter, the implementation mode of the optical thin film manufacturing method of the present invention will be described in detail with reference to the drawings.

[0014] (A-1) Outline In recent years, as an alternative to optical components using glass, the demand for optical components using plastics has increased. For example, a method of forming a fine concavo-convex structure on the surface of a substrate to prevent surface reflection of an optical lens is known.

[0015] As one of such fine concavo-convex structures, there is a structure called a moth-eye structure (so-called Moth-eye because it imitates the fine protrusions on the surface of a moth's eye). In the present invention, the moth-eye structure is taken as an example of the fine concavo-convex structure, but it is not limited to the moth-eye structure.

[0016] In the past, as a method of forming a moth-eye structure on the surface of a plastic substrate, for example, there is a method of forming a fine concavo-convex structure by injection molding using a mold.

[0017] However, in this method, when the molded product is taken out of the mold, the resin may stick to the mold, resulting in damage to the fine concavo-convex structure, and it is difficult to adopt it as a production method of the product.

[0018] In addition, as another method, there is a method using ion sputtering. Ion sputtering is one of the phenomena generated by ion irradiation. By irradiating the surface of a PMMA substrate with ions, the surface is modified and the surface shape is deformed. In the past, for example, a plasma gun was installed in a vacuum evaporation device, and ion irradiation was performed during film formation to activate evaporation molecules and improve film strength.

[0019] The inventors of the present application confirmed the formation of a moth-eye shape (a shape with fine uneven structures) on the surface of a PMMA substrate by irradiating the PMMA substrate with ions instead of forming (laminating) a multilayer film on the surface of the substrate, and confirmed the antireflection effect and spectral characteristics of the PMMA substrate having the moth-eye shape.

[0020] PMMA forms chain bonds, and the C-O part of C-OOCH3 is broken by plasma to form a moth-eye shape. In fact, referring to this method, using a plasma gun, by changing conditions such as the adjustment of argon gas flow rate, oxygen flow rate, and ion irradiation power, a moth-eye shape can be formed on the surface of the substrate. In addition, in another method, namely CVD (chemical vapor deposition apparatus), by adjusting the plasma discharge of argon gas flow rate, oxygen flow rate, and high-frequency power, a moth-eye can also be formed. By forming fine uneven structures on the surface of these substrates, the antireflection effect or the spectral characteristic effect of increasing light transmittance can be confirmed.

[0021] However, when tested in the high-temperature environment required in the automotive field, the spectral characteristics change, and it returns to the surface reflection of the original lens, resulting in the failure to achieve the purpose. This can be considered that the moth-eye shape as the fine uneven structure collapses in the high-temperature environment.

[0022] Therefore, the inventors of the present application repeatedly conducted in-depth research and proposed the following solution: Instead of forming (laminating) an existing antireflection film formed of a multilayer film on the substrate, a thin protective film that does not generate film (protective film) stress is formed on the fine uneven structure shape (for example, moth-eye shape) on the surface of the synthetic resin substrate.

[0023] As a result, the fine uneven structure shape can be maintained in a high-temperature environment, the heat resistance of the optical component can be improved, and the surface antireflection function and spectral characteristics can be confirmed.

[0024] The protective film can maintain the fine uneven structure and improve the heat resistance. The material of the protective film is preferably silicon oxide with a refractive index lower than that of the synthetic resin of the substrate. If the refractive index is high, the reflection increases due to light interference, so a material with an intermediate refractive index is preferred. For example, a material with a refractive index of 1.6 or less is good, and further preferably 1.65 or less. The optical film thickness of the protective film at an irradiation wavelength of 550 nm is preferably λ / 50 to λ / 16.

[0025] The protective film functions as an antireflection film that suppresses the reflection on the surface of the substrate, and in addition, it also has spectral characteristics of splitting the wavelengths of light. Furthermore, the protective film functions as a film that can maintain the shape of the fine uneven structure even in a high-temperature environment. In the present invention, the protective film is exemplified by a silicon oxide (SiO 2 ) film or a silicon oxide mixture (SiO x ) film, but is not limited thereto.

[0026] (A-2) Manufacturing method of optical thin film Hereinafter, the manufacturing method of the optical thin film of this embodiment will be described.

[0027] The manufacturing method of the optical thin film of this embodiment forms a fine concavo-convex structure on the surface of a substrate by ion irradiation, and forms a protective film for the fine concavo-convex structure on the surface of the substrate.

[0028] (1) Substrate The substrate is a plastic substrate (transparent substrate) made of a plastic (synthetic resin) with excellent transparency. As the plastic of the transparent substrate, a chain-linked polymethyl methacrylate resin (PMMA) with excellent transparency is used.

[0029] The present invention utilizes the following characteristics of PMMA: the surface of the substrate is modified by ion irradiation, so that the surface changes and a moth-eye shape is formed on the surface of the substrate. Therefore, as long as it is a synthetic resin that can form a fine concavo-convex structure on the surface by ion irradiation, it is not limited to PMMA, and other synthetic resins can be widely used.

[0030] In addition, polycarbonate (PC) having a benzene ring and cycloolefin polymer (COP: Cycro Olefin Polymer) of a cyclic compound cannot form a fine concavo-convex structure shape on the surface of their substrates by ion irradiation, and it is considered that they are difficult to be used as substrates.

[0031] (2) Material (evaporation material) The material is preferably a material having a refractive index lower than that of the plastic (synthetic resin) used in the substrate. This is because if a material having a refractive index higher than that of the synthetic resin of the substrate is used, the reflection may increase due to light interference.

[0032] In this embodiment, the material (evaporation material) is silicon oxide. In addition, the material (evaporation material) is not limited to silicon oxide, and for example, aluminum oxide, titanium oxide, tantalum oxide, zirconium oxide, etc. can also be used.

[0033] (3) Formation method The formation method of forming a protective film on the surface of the substrate is roughly the following method: (a) a method of directly evaporating silicon oxide as the material; (b) making hexamethyldisiloxane (HMDS) into Si+SiO 2 +SiO mixed film material (hereinafter written as "SiO x ".).

[0034] (3-1) Pre-process First, when implementing a fine concavo-convex structure on a substrate, there are sometimes stains, fingerprints, oil, etc. on the surface of the substrate. Therefore, pure water and a neutral detergent are added to an ultrasonic cleaning machine, and the substrate is placed therein for ultrasonic cleaning. In addition, since PMMA has a high water absorption rate, it is also preferable to pre-dry the substrate.

[0035] (3-2) Place the substrate in a vacuum device. After completing the above-mentioned previous processes, place the substrate in a vacuum device. Here, the exhaust system of the vacuum device is not particularly limited. For example, a vacuum pump such as a diffusion pump or a turbomolecular pump can be used.

[0036] Examples of the device used in the optical thin film forming method illustrate the case of using either one or both of a vacuum evaporation device equipped with a plasma gun and a chemical vapor deposition device.

[0037] In the case of using a vacuum evaporation device equipped with a plasma gun, "Process A" of forming a fine concavo-convex structure on the substrate surface and "Process B" of forming a protective film on the fine concavo-convex structure on the substrate surface can be considered.

[0038] In the case of using a chemical vapor deposition device, "Process C" of forming a moth-eye shape on the substrate surface and "Process D" of forming a protective film on the moth-eye shape on the substrate surface can also be considered in the same way.

[0039] In the following examples (Examples 1 to 5), effective processes among "Process A" to "Process D" can be combined.

[0040] Details will be described later. There is a method of forming a "moth-eye shape" and a "protective film" by using both a vacuum evaporation device and a chemical vapor deposition device through a combination of processes, and there is also a method of forming a "moth-eye shape" and a "protective film" by using only one of the vacuum evaporation device or the chemical vapor deposition device.

[0041] In other words, the former method (i.e., the method of using two devices) can be said to be a method of forming a "moth-eye shape" and a "protective film" in two stages.

[0042] On the contrary, the latter method (i.e., the method of using one device) can be said to be a method of forming a "moth-eye shape" and a "protective film" in one stage. That is, since the processes can be continuously advanced with one device, the productivity of optical components can be improved, and efficient manufacturing can be expected.

[0043] (3-3) Vacuum evaporation device equipped with a plasma gun A vacuum evaporation apparatus equipped with a plasma gun generally includes: a vacuum chamber, a substrate setting unit (rack) for setting a substrate in the vacuum chamber, an evaporation source provided with a crucible for setting a material as the evaporation material, an electron gun, a plasma gun, a heater for heating the substrate, and a vacuum pump as an exhaust system.

[0044] [Process A] The substrate is set on the rack with the surface of the substrate facing the evaporation source, and the material as the evaporation material is set on the crucible. Then, after reducing the pressure in the vacuum chamber by the vacuum pump, the substrate is heated by the heater as needed. Then, the evaporated and sublimated material substance (evaporation substance) in the vacuum chamber is irradiated with ions by the plasma gun, the shape of the substrate surface changes, and a fine concavo-convex structure shape is formed on the substrate surface. That is, a moth-eye shape is formed on the substrate surface. This process is called "Process A". According to Process A, the substance is activated by ion irradiation, thereby improving the film strength.

[0045] In addition, the evaporation and sublimation of the evaporation substance are not necessary. In the following Examples 1 to 5 exemplified in the present embodiment, the cases where the evaporation and sublimation of the evaporation substance are not performed are exemplified.

[0046] [Process B] The substrate is set on the rack with the surface of the substrate facing the evaporation source, and the material as the evaporation material is set on the crucible. Then, after reducing the pressure in the vacuum chamber by the vacuum pump, the substrate is heated by the heater as needed. So far, a part of Process A is repeated.

[0047] Then, in the vacuum chamber, the evaporation substance is dissolved and evaporated by the electron gun, and the evaporated evaporation material is deposited on the substrate surface to form a protective film on the substrate surface. This process is called "Process B".

[0048] (3-4) Chemical vapor deposition apparatus (CVD) The chemical vapor deposition apparatus generally includes: a reaction chamber, a substrate setting unit for setting a substrate in the reaction chamber, a high-frequency power supply, a material supply unit for supplying a material vaporized by plasma discharge through high frequency to the reaction chamber, a supply unit for supplying a gas (carrier gas) to the reaction chamber, and a vacuum pump as an exhaust system for exhausting the inside of the reaction chamber.

[0049] [Process C] Set the substrate in the substrate setting section and set the material in the material supply section. Then, evacuate the reaction chamber using a vacuum pump, supply gas using the supply section, and make the gas flow from the supply section to the vacuum pump in the reaction chamber. Then, generate plasma at a high frequency (e.g., 36.56 MHz), supply the material evaporated from the material supply section into the reaction chamber, and form a shape of a fine concavo-convex structure on the substrate surface. This process is called "Process C".

[0050] Here, the types of gas supplied by the supply section into the reaction chamber can be argon, oxygen, nitrogen, etc.

[0051] [Process D] Set the substrate in the substrate setting section and set the material in the material supply section. Then, evacuate the reaction chamber using a vacuum pump, supply gas using the supply section, and make the gas flow from the supply section to the vacuum pump in the reaction chamber. Up to this point, it is repeated with a part of Process C.

[0052] Then, in the material supply section, perform plasma discharge at a high frequency to vaporize organic silicon such as hexamethyldisiloxane (HMDS), tetraethoxysilane (TEOS), and triethoxysilane (TRIES), and polymerize the material vaporized by the high frequency to form SiOx. Then, the material supply section supplies SiOx into the reaction chamber and forms a protective film on the surface of the substrate. This process is called "Process D".

[0053] (3 - 5) Formation conditions of the fine concavo-convex structure on the substrate surface Refer to Figure 1 and Figure 2 Describe the respective formation conditions of "Process A" and "Process C" for forming a fine concavo-convex structure shape on the substrate surface.

[0054] Figure 1 (A) of is the formation condition of the fine concavo-convex structure of Process A, Figure 1 (B) of is the result of confirming the transmittance characteristics of the substrate having a fine concavo-convex structure under each condition.

[0055] In Figure 1 (B), the horizontal axis represents the wavelength [nm], the vertical axis represents the transmittance [%], the wavelength (λ) is changed from 400 nm to 750 nm, and at the same time, light is made to pass through the substrate to confirm the transmittance at each wavelength.

[0056] According to Figure 1 (B), it can be seen that at each wavelength from 400 nm to 750 nm, the result of condition number 102 maintains a transmittance of about 95% - 97% or so, which is a good result. Therefore, in the following examples and comparative examples, when forming a fine concavo-convex structure on the substrate surface in Process A, it is formed under the conditions of condition number 102.

[0057] Figure 2 (A) is the formation condition of the fine uneven structure of process C, Figure 1 (B) is the result of confirming the transmission characteristics of the substrate having a fine uneven structure under each condition.

[0058] According to Figure 2 (B), the result of condition number 111 maintains a high transmittance at each wavelength from 400 nm to 750 nm. In particular, for light with wavelengths from 470 nm to 750 nm, the transmittance is maintained at about 90% to 97%. Therefore, in the following examples and comparative examples, a fine uneven structure is formed on the substrate surface under the condition of condition number 111.

[0059] (A-3) Description of the example (A-3-1) Example 1 (Process A + Process B) Figure 3 It is a diagram showing the spectroscopic characteristics of the substrate on which a fine uneven structure and a protective film are formed in the process of Example 1. Example 1 is a combination of Process A and Process B.

[0060] In Process A, the substrate is set on the rack of the vacuum evaporation apparatus, and the air pressure in the vacuum chamber is evacuated to 5×10 -3 (5E-3) Pa by a vacuum pump to perform ion irradiation. In addition, a dome-shaped apparatus is used as the vacuum evaporation apparatus, and an apparatus with a device diameter (the diameter of the vacuum chamber) of 1600φ is used.

[0061] Process B uses the vacuum evaporation apparatus of Process A. That is, without opening the vacuum chamber, SiO used as the material is evaporated by an electron gun 2 and a SiO film is formed on the substrate surface. 2

[0062] In Example 1, the optical film thickness of the SiO formed on the substrate surface is changed, and light of each wavelength from 400 nm to 750 nm is irradiated to each sample substrate, and the transmission characteristics are measured. 2

[0063] SiO 2 The film conditions are as follows: when the light wavelength λ irradiated on the substrate is 550 nm, the optical film thickness is λ / 32, λ / 16, λ / 8, λ / 4, λ / 3, λ / 2. These six substrates and the substrate without SiO film formation 2 (uncoated) are used as samples.

[0064] According to Figure 3From the results, it can be seen that at each wavelength from 400 nm to 750 nm, the transmittance of the substrate with an optical film thickness of λ / 32 to λ / 2 (λ / 32, λ / 16, λ / 8, λ / 4, λ / 3, λ / 2) is about 90% or more, and any substrate maintains a high transmittance.

[0065] It can be seen from Figure 3 that among the six substrates, for light of each wavelength from 470 nm to 750 nm, each substrate with λ / 32 to λ / 3 (λ / 32, λ / 16, λ / 8, λ / 4, λ / 3) maintains a transmittance of about 92% or more, and the antireflection effect is good. Furthermore, each substrate with λ / 32 to λ / 4 (λ / 32, λ / 16, λ / 8, λ / 4) maintains a transmittance of about 95% to 99%, and has a high antireflection effect.

[0066] In addition, it can be seen that among the six substrates, each substrate with λ / 3 and λ / 2 has a tendency that the transmittance increases as the wavelength value increases.

[0067] Furthermore, it can be known that, however, among the six substrates, each substrate with λ / 32 to λ / 3 (λ / 32, λ / 16, λ / 8, λ / 4, λ / 3) has a high transmittance for light of each wavelength from 470 nm to 750 nm, but has a tendency that the transmittance is higher for wavelengths lower than 550 nm.

[0068] (A-3-2) Example 2 (Process A + Process D) Figure 4 It is a diagram showing the spectral characteristics of a substrate on which a fine concavo-convex structure and a protective film are formed in the process of Example 2. Example 2 is a combination of Process A and Process D.

[0069] In Process A, a substrate is set on the stage of a vacuum evaporation apparatus (dome type 1600φ), and the air pressure in the vacuum chamber is evacuated to 5×10 -3 (5E-3) Pa to perform ion irradiation.

[0070] In Process D, the substrate is reset on the substrate setting part of a chemical vapor deposition apparatus, the air pressure in the reaction chamber is evacuated to 0.2 Pa, and a SiOx film formed by plasma discharge polymerization of hexamethyldisiloxane (HMDS) is formed on the surface of the substrate. In addition, in order to move to Process D, the vacuum chamber of the vacuum evaporation apparatus is opened to take out the substrate, and the substrate is reset in the chemical vapor deposition apparatus.

[0071] In Example 2, the optical film thickness of SiOx formed on the surface of the substrate is changed, and light of each wavelength from 400 nm to 750 nm is irradiated to each sample substrate, and the transmission characteristics are measured.

[0072] The film conditions of SiOx are that when the wavelength λ of the light irradiating the substrate is 550 nm, the optical film thickness is λ / 32, λ / 16, λ / 8, λ / 4. These four substrates and the substrate without SiO film formation 2 (uncoated) are used as samples.

[0073] According to Figure 4 the results, at each wavelength from 400 nm to 750 nm, the transmittance of the substrates with an optical film thickness of λ / 32 to λ / 4 (λ / 32, λ / 16, λ / 8, λ / 4) is about 92% or more, and any substrate maintains a high transmittance.

[0074] In addition, it can be known that even among the four substrates, each substrate with λ / 32 to λ / 8 (λ / 32, λ / 16, λ / 8) maintains a transmittance of about 94% to 97% for the light of each wavelength from 470 nm to 750 nm. Furthermore, each substrate with λ / 32 and λ / 16 maintains a transmittance of about 95% or more for the light of each wavelength from 470 nm to 750 nm, having a high antireflection effect.

[0075] Furthermore, it can be known that even among the four substrates, each substrate with λ / 32 and λ / 16 has a high transmittance for the light of each wavelength from 470 nm to 750 nm, but has a tendency of higher transmittance for wavelengths lower than 550 nm.

[0076] (A-3-3) Example 3 (Process C + Process D) Figure 5 is a diagram showing the spectroscopic characteristics of a substrate on which a fine concavo-convex structure and a protective film are formed in the process of Example 3. Example 3 is a combination of Process C and Process D.

[0077] In Process C, a substrate is set on the substrate setting part of the chemical vapor deposition apparatus, the pressure in the reaction chamber is evacuated to 0.2 Pa, and plasma discharge is performed.

[0078] In Process D, the chemical vapor deposition apparatus of Process C is directly used without opening the reaction chamber, and a SiOx film formed by plasma discharge polymerization of hexamethyldisiloxane (HMDS) is formed on the surface of the substrate.

[0079] In Example 3, the optical film thickness of SiOx formed on the surface of the substrate is changed, and light of each wavelength from 400 nm to 750 nm is irradiated on each sample substrate to measure the transmission characteristics.

[0080] The film conditions of SiOx are that when the wavelength λ of the light irradiating the substrate is 550 nm, the optical film thickness is λ / 32, λ / 16, λ / 8, λ / 4. These four substrates and the substrate without SiO film formation 2 (uncoated) are used as samples.

[0081] According to Figure 5 the results, among the wavelengths used in the measurement, at each wavelength from 480 nm to 750 nm, the transmittance of each substrate with an optical film thickness of λ / 32 to λ / 4 (λ / 32, λ / 16, λ / 8, λ / 4) is about 90% or more, and any substrate maintains a high transmittance.

[0082] In addition, it can be seen that even among the four substrates, for each substrate with an optical film thickness of λ / 32 to λ / 8 (λ / 32, λ / 16, λ / 8), the transmittance is about 93% or more at wavelengths of about 520 nm or more, showing a high antireflection effect.

[0083] (A-3-4) Example 4 (Process C + Process B) Figure 6 This is a diagram showing the spectral characteristics of a substrate on which a fine concavo-convex structure and a protective film are formed in the process of Example 4. Example 4 is a combination of Process C and Process B.

[0084] In Process C, a substrate is set on the substrate setting part of the chemical vapor deposition apparatus, the pressure in the reaction chamber is evacuated to 0.2 Pa, and plasma discharge is performed.

[0085] In Process B, the substrate is set on the rack of the vacuum evaporation apparatus (dome type 1600φ), the pressure in the vacuum chamber is evacuated to 2×10 -3 (2E-3) Pa, and SiO 2 is evaporated using an electron gun, and a SiO 2 film is formed on the surface of the substrate. In addition, in order to move to Process B, the reaction chamber of the chemical vapor deposition apparatus is opened to take out the substrate, and the substrate is reset in the vacuum evaporation apparatus.

[0086] In Example 4, the optical film thickness of the SiO 2 formed on the surface of the substrate is changed, and light of each wavelength from 400 nm to 750 nm is irradiated onto each sample substrate to measure the transmittance characteristics.

[0087] SiO 2 The film conditions are such that when the light wavelength λ irradiated on the substrate is 550 nm, the optical film thicknesses are λ / 32, λ / 16, λ / 8, λ / 4, λ / 3, and λ / 2. These six substrates and the substrate without SiO 2 film formation (uncoated) are used as samples.

[0088] According to Figure 6From the results, among the wavelengths used in the measurement, for each wavelength in the range of approximately 470 nm to 750 nm, the transmittance of each substrate with an optical film thickness of λ / 32 to λ / 2 (λ / 32, λ / 16, λ / 8, λ / 4, λ / 3, λ / 2) is approximately 90% or more, and any substrate maintains a high transmittance.

[0089] In addition, it can be seen that even among the four substrates, for each substrate with an optical film thickness of λ / 32 to λ / 3 (λ / 32, λ / 16, λ / 8, λ / 4, λ / 3), the transmittance is approximately 93% or more at wavelengths of approximately 500 nm or more, showing a high antireflection effect.

[0090] (A-3-5) Example Five (Process A + Process B) Figure 7 It is a diagram showing the spectral characteristics of a substrate on which a fine concavo-convex structure and a protective film are formed in the process of Example Five.

[0091] Example Five is a combination of Process A and Process B, and the material (evaporation material) for the protective film is alumina.

[0092] In Process A, a substrate is set on the rack of a vacuum evaporation apparatus, and the air pressure in the vacuum chamber is evacuated to 5×10 -3 (5E-3) Pa by a vacuum pump to perform ion irradiation. In addition, a dome-shaped apparatus is used as the vacuum evaporation apparatus, and an apparatus with a device diameter (diameter of the vacuum chamber) of 1600φ is used.

[0093] Process B uses the vacuum evaporation apparatus of Process A. That is, without opening the vacuum chamber, Al 2 O 3 is evaporated using an electron gun to form an Al 2 O 3 film on the surface of the substrate.

[0094] In Example Five, the optical film thickness of Al 2 O 3 on the surface of the substrate is changed, and light of each wavelength from 400 nm to 750 nm is irradiated on each sample substrate to measure the transmittance characteristics.

[0095] Al 2 O 3 The film conditions are as follows: when the light wavelength λ irradiated on the substrate is 550 nm, the optical film thickness is λ / 32, λ / 16, λ / 8. These six substrates and the substrate without Al 2 O 3 film formation (uncoated) are used as samples.

[0096] According to Figure 7From the results, among the three substrates, each substrate with λ / 32 to λ / 16 (λ / 32, λ / 16) has a transmittance of about 91% or more for light of each wavelength from 400 nm to 750 nm, maintaining a relatively high transmittance. In particular, it can be seen that among the three substrates, the substrate with λ / 32 has a transmittance of about 94% or more for light of each wavelength from 400 nm to 750 nm, maintaining a relatively high transmittance.

[0097] (A-3-6) Comparative Example 1 (Process A) Figure 8 It is the result of representing the spectral characteristics of the substrate before the high-temperature test and the spectral characteristics of the substrate in a high-temperature environment using the substrate with the fine concavo-convex structure formed in Process A.

[0098] In Comparative Example 1, a fine concavo-convex structure was formed on the surface of the substrate in Process A, and the transmittance characteristics of the substrate were measured in a high-temperature environment for confirmation.

[0099] In Process A, the substrate was set on the rack of the vacuum evaporation apparatus, and the air pressure in the vacuum chamber was evacuated to 5×10 -3 (5E-3) Pa for ion irradiation.

[0100] In Figure 8 , the dashed line represents the result of the spectral characteristics of the substrate before the high-temperature test, and the solid line represents the result of the spectral characteristics of the substrate under the high-temperature test.

[0101] According to Figure 8 's results, at each wavelength from 400 nm to 750 nm, the transmittance of the substrate subjected to the high-temperature test is lower than that of the substrate before the high-temperature test. That is, it can be seen that the fine concavo-convex structure formed on the surface of the substrate has a reduced transmittance (spectral characteristics) due to being placed in a high-temperature environment.

[0102] (A-3-7) High-temperature test results of Example 1 (Process A + Process B) Figure 9 It is the result of representing the spectral characteristics before the high-temperature test and the spectral characteristics in a high-temperature environment using the substrate of Example 1. Here, a substrate with a film thickness of λ / 8 of SiO 2 was used.

[0103] According to Figure 9 's results, it can be seen that in a high-temperature environment, at each wavelength from 400 nm to 750 nm, the transmittance of the substrate after the high-temperature test is approximately the same as that of the substrate before the high-temperature test. That is, it can be seen that even in a high-temperature environment, the transmittance (spectral characteristics) does not decrease, and it has a high antireflection effect.

[0104] In the past, when the temperature increased, the fine uneven structure on the surface of the substrate collapsed, and the antireflection effect and spectral characteristics deteriorated (see Comparative Example 1).

[0105] In contrast, as shown in Example 1, through Process B, for the fine uneven structure on the surface of the substrate, a SiO 2 film was formed as a protective film. Thus, even at high temperatures, the antireflection effect and spectral characteristics could be maintained. In other words, even in the target high-temperature environment, the protective film could suppress the collapse of the fine uneven structure and maintain the antireflection effect and spectral characteristics.

[0106] In addition, in Example 1, the same vacuum evaporation apparatus was used, and Processes A and B could be continuously carried out. Therefore, the manufacturing efficiency of the optical component could be made good.

[0107] (A-3-8) High-temperature test results of Example 3 (Process C + Process D) Figure 10 These are the results showing the spectral characteristics before the high-temperature test and the spectral characteristics in the high-temperature environment of the substrate of Example 3. Here, a substrate with a SiOx film thickness of λ / 16 was used.

[0108] According to Figure 10 the results, in the high-temperature environment, at each wavelength from about 480 nm to 750 nm, the transmittance of the substrate after the high-temperature test was approximately the same as that of the substrate before the high-temperature test. That is, it was found that even in the high-temperature environment, the transmittance (spectral characteristics) did not deteriorate and had a high antireflection effect.

[0109] The situation of Example 3 was the same as that of (A-3-7). Through Process D, a SiOx film was formed as a protective film for the fine uneven structure on the surface of the substrate. Thus, even at high temperatures, the antireflection effect and spectral characteristics could be maintained. This was because, even in the target high-temperature environment, the protective film could suppress the collapse of the fine uneven structure and maintain the antireflection effect and spectral characteristics.

[0110] In addition, in Example 3, Processes C and D could also be continuously carried out using the same chemical vapor deposition apparatus. Therefore, the manufacturing efficiency of the optical component could be made good.

[0111] (A-3-9) Comparison with other antireflection films Figure 11 These are the comparison results of the antireflection effects between Example 1 and other antireflection films. Figure 12 This is a graph showing the spectral characteristics of Example 1 and other antireflection films.

[0112] As Figure 11As shown, two examples of other antireflection films are listed: "a four-layer antireflection film using vacuum evaporation" and "a single-layer antireflection film using vacuum evaporation".

[0113] In addition, as Figure 11 shown, the test contents include the spectral characteristics representing the average transmittance from 450 nm to 650 nm, a high-temperature test (90 °C), and a high-temperature test (100 °C). In addition, the spectral characteristics utilize the Figure 12 results of the spectral characteristics.

[0114] The four-layer antireflection film obtained by vacuum evaporation has an average transmittance of approximately 98% from 450 nm to 650 nm and excellent spectral characteristics. In the automotive field, in the high-temperature tests (90 °C) and high-temperature tests (100 °C) required in the optical field, it is rated as "×" due to the appearance of microcracks.

[0115] The single-layer film obtained by vacuum evaporation has no problem in the high-temperature test (90 °C), but cracks are generated in the high-temperature test (100 °C), so it is rated as "×".

[0116] According to the Figure 9 results, the average transmittance of Example 1 from 450 nm to 650 nm is approximately 98% or more. In addition, excellent results showing no change are demonstrated in the high-temperature test and the high-temperature and high-humidity test. Since Example 1 is manufactured using the same device, continuous production can be achieved, and mass production can also be expected.

[0117] (A-4) Effects of the Embodiment As described above, according to the present embodiment, it is possible to form a protective film on the fine uneven structure formed on the surface of the synthetic resin substrate, and manufacture an optical component with high antireflection effect in a high-temperature environment.

Claims

1. A manufacturing method of an optical component, characterized in that, it comprises: a fine concavo-convex structure forming step of changing the surface of a substrate by ion irradiation to form a fine concavo-convex structure on the surface of the substrate; a protective film forming step of evaporating a vapor deposition material and vapor-depositing it on the surface of the substrate to form a protective film on the fine concavo-convex structure formed on the surface of the substrate.

2. The manufacturing method of the optical component according to claim 1, characterized in that, in the fine concavo-convex structure forming step, plasma is discharged in a reduced-pressure container, and ion irradiation is performed in this plasma environment, thereby forming the fine concavo-convex structure on the surface of the substrate, in the protective film forming step, in the same container as the fine concavo-convex structure forming step, silicon oxide is used as the vapor deposition material, and the silicon oxide is attached to the surface of the substrate by vacuum vapor deposition to form a silicon oxide film on the fine concavo-convex structure on the surface of the substrate.

3. The manufacturing method of the optical component according to claim 1, characterized in that, in the fine concavo-convex structure forming step, plasma is discharged in a reduced-pressure container, and ion irradiation is performed in this plasma environment, thereby forming the fine concavo-convex structure on the surface of the substrate, in the protective film forming step, in the same container as the fine concavo-convex structure forming step, an organosilicon compound is used as the vapor deposition material, and the organosilicon compound is vaporized by chemical vapor deposition to form a silicon oxide mixed film on the fine concavo-convex structure on the surface of the substrate.

4. The manufacturing method of the optical component according to claim 1, characterized in that, in the fine concavo-convex structure forming step, plasma is discharged in a reduced-pressure container, and ion irradiation is performed in this plasma environment, thereby forming the fine concavo-convex structure on the surface of the substrate, in the protective film forming step, in a container different from the fine concavo-convex structure forming step, an organosilicon compound is used as the vapor deposition material, and the organosilicon compound is vaporized by chemical vapor deposition to form a silicon oxide mixed film on the fine concavo-convex structure on the surface of the substrate.

5. The manufacturing method of the optical component according to claim 1, characterized in that, in the fine concavo-convex structure forming step, plasma is discharged in a reduced-pressure container, and ion irradiation is performed in this plasma environment, thereby forming the fine concavo-convex structure on the surface of the substrate, in the protective film forming step, in a container different from the fine concavo-convex structure forming step, silicon oxide is used as the vapor deposition material, and the silicon oxide is attached to the surface of the substrate by vacuum vapor deposition to form a silicon oxide film on the fine concavo-convex structure on the surface of the substrate.

6. The manufacturing method of the optical component according to claim 1, characterized in that, the vapor deposition material is a material with a refractive index of 1.6 or less, and the optical film thickness of the protective film when irradiated with a wavelength of 550 nm is λ / 50 to λ / 16.

7. The manufacturing method of the optical component according to claim 2 or 5, characterized in that, In the protective film forming step, the optical film thickness of the silicon oxide film at a wavelength of 550 nm is λ / 50 to λ / 3.

8. The method for manufacturing an optical component according to claim 3 or 4, wherein, in the protective film forming step, the optical film thickness of the silicon oxide mixed film at a wavelength of 550 nm is λ / 50 to λ / 8.

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