JP2009151192A - Method for manufacturing lens frame member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a lens frame member which is capable of suitably forming a fine relief structure having superior anti-reflectiveness on the surface of an inwall, for suppressing the occurrence of flare, ghost, etc. <P>SOLUTION: The lens frame member 1 is made of polycarbonate resin and an annular lens support portion 1a is formed in the inwall. A fine relief structure layer 1b is formed in an inwall surface on the right side of the lens support portion 1a as follows: first a Zn metal layer is formed by plate-processing after the injection molded lens frame member 1 is cleaned, then, an oxide film is formed in a metal layer surface by leaving it as it is, and then, the lens support portion 2 and the inwall on the left side of the lens support portion 2 are masked, then, exposed to heating water vapor at 150°C for 30 minutes and then, heat-treated at 100°C for 30 minutes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a lens frame member having excellent antireflection properties, which is used for holding an optical element such as a lens in an optical apparatus such as a camera or a microscope.

  In a lens frame member of an optical device such as a camera or a microscope, if stray light is reflected by the inner wall surface of the lens frame member and enters the optical path, a ghost or flare is generated. Therefore, the reflected light from the inner wall surface of the lens frame member Baffles and hoods are used to suppress the problem. Originally, it is ideal to avoid or reduce the reflected light from the inner wall of the lens frame member without using a member such as a baffle or hood, but it is cylindrical and has a complicated shape like a lens frame. There is no technique for anti-reflection treatment on things. In general, an antireflection film due to interference used for an optical member is formed by vapor deposition or sputtering. Therefore, if it has a cylindrical inner wall surface or a complicated shape, it does not wrap around, and a portion that cannot be formed is formed.

  On the other hand, in recent years, for the purpose of application to displays, solar cells, and optical elements, instead of the conventional antireflection film due to interference, a fine layer formed on the surface of the substrate in sub-wavelength level units. Technology has been developed to form an antireflection film having a rough concavo-convex structure (hereinafter simply referred to as a fine concavo-convex structure) or to directly process the surface of a substrate into a fine concavo-convex structure. The fine concavo-convex structure is usually formed so that the occupied volume increases as it goes from the air interface side to the base material side, so that for incident light, the refractive index is the refractive index of air. It seems that the refractive index of the base material gradually changes, and the reflection occurring at the interface having different refractive indexes is suppressed. For this reason, the antireflection function by such a fine concavo-convex structure is superior in wavelength dependency and angle dependency compared to the conventional antireflection function by interference.

  Further, as a general method for forming such a fine concavo-convex structure, a lithography method, a sheet attaching method, an anodizing method, and the like are known in addition to a method of pressing with a mold. And in the following patent document 1, using the method of pressing with a molding die among them, a resin made by forming a fine concavo-convex structure (antireflection structure) on the inner wall of the opening formed in the plate-like portion These members are described. In the case of lithography, a photosensitive material is applied to the surface, and the photosensitive material is exposed through a mask patterned with a fine concavo-convex structure or exposed in a pattern with an electron beam or X-ray. The unexposed portion is removed to obtain a fine concavo-convex structure. In the sheet attaching method, the fine uneven structure is formed on the surface of the sheet using the above-described method for forming the fine uneven structure, and the sheet is attached to the surface of the lens frame member. In the anodic oxidation method, the surface of the aluminum alloy is immersed in a solution such as an acid, and a porous layer is formed when an external power source is applied to obtain a fine concavo-convex structure.

  Further, Patent Document 2 below describes a method of forming an alumina transparent thin film having a petal-like fine concavo-convex structure using a sol-gel method. In the method described therein, an amorphous alumina film is formed on the surface of the base material from a coating solution of aluminum-sec-butoxide and ethyl acetoacetate, which is a stabilizer, by dip coating or spin coating. Then, it is dried and baked and then treated with hot water, and again dried and baked to obtain a petal-like alumina transparent film.

JP 2006-285223 A JP 2006-259711 A

  By the way, the method of pressing with a molding die as described above is effective when forming a fine uneven structure on the inner wall of an opening formed in a thin plate-like portion as described in Patent Document 1. . However, in the case of a lens barrel member having a cylindrical shape and an inner wall having a complicated shape, it is impossible to press the molding die in contact with the entire inner wall surface. In addition, if a fine concavo-convex structure is formed using the above-described lithography method, it is difficult to selectively apply a photosensitive substance to a desired location on the inner wall, and a shadowed portion is generated during exposure. There is an inconvenience. In the case of the sheet pasting method, it is very difficult to stick the sheet along the complicated shape of the inner wall of the lens frame member. Further, when the anodizing method is used, the lens frame member is immersed in the liquid, so that a fine concavo-convex structure is formed on the entire surface of the lens frame member, and applicable materials are also limited. Furthermore, using the sol-gel method, when trying to form a film on the inner wall of a lens barrel member with a complicated shape by the dip coating method, spin coating method, etc., a portion that cannot be coated is formed, and a fine uneven structure is formed at a desired location. May not be formed.

  The present invention has been made to solve such problems, and its object is to provide excellent reflection on the surface of the inner wall in order to suppress the occurrence of flares, ghosts and the like caused by stray light. An object of the present invention is to provide a method of manufacturing a lens frame member capable of suitably forming a fine concavo-convex structure having a preventive property.

  In order to achieve the above object, a method of manufacturing a lens frame member according to the first invention of the present application is based on a metal having a higher ionization tendency than hydrogen on the inner wall surface of a lens frame member processed into a predetermined shape with a predetermined material. Forming a metal layer, forming a surface of the metal layer into an oxide layer or hydroxide layer, and subjecting the oxide layer or hydroxide layer to hot water treatment or steam treatment And the step of forming the concavo-convex structure layer.

Further, the second invention is characterized in that the metal is any one of Al, Mg, and Zn on the premise of the first invention.
The third invention is characterized in that the metal layer is formed by a plating method on the premise of the first or second invention.
The fourth invention is characterized in that the oxide layer or the hydroxide layer is formed by acid or alkali treatment on the premise of any of the first to third inventions.

  In order to achieve the above object, a method for manufacturing a lens frame member according to the fifth invention of the present application is characterized in that an oxide is formed on the inner wall surface of a lens frame member processed into a predetermined shape with a metal having a higher ionization tendency than hydrogen. It is characterized in that a step of forming a layer or a hydroxide layer and a step of forming a fine concavo-convex structure layer by performing hot water treatment or steam treatment on the oxide layer or hydroxide layer are performed in order.

The sixth invention is characterized in that, based on the fifth invention, the metal is any one of Al, Mg, and Zn.
The seventh invention is characterized in that the oxide layer or the hydroxide layer is formed by acid or alkali treatment on the premise of the fifth or sixth invention.

  Furthermore, an eighth invention is characterized in that the film thickness of the fine concavo-convex structure layer is 20 to 300 nm on the premise of any one of the first to seventh inventions.

  In the case of a lens frame member processed into a predetermined shape with a predetermined material, the present invention forms a metal layer (film) on the inner wall surface in advance and then oxidizes or hydroxideizes the surface. In the case of a lens frame member that has been processed into a predetermined shape from the beginning only with a metal material, the inner wall surface is directly oxidized or hydroxideized, and in any case However, since the fine concavo-convex structure layer (film) is formed by hot water treatment or steam treatment, it is possible to form a fine concavo-convex structure layer having excellent antireflection properties on the inner wall surface having a complicated shape. It is possible to suppress the generation of ghosts and flares due to stray light.

  The invention according to claim 1 of the present application includes a step of forming a metal layer made of a metal having a higher ionization tendency than hydrogen on the inner wall surface of a lens frame member processed into a predetermined shape with a predetermined material, and a surface of the metal layer. The step of forming the oxide layer or the hydroxide layer and the step of forming the fine concavo-convex structure layer by subjecting the oxide layer or the hydroxide layer to hydrothermal treatment or steam treatment are performed in order, A lens frame member having antireflection properties is manufactured.

  In this case, the material of the lens frame member that is primarily processed into a predetermined shape is not particularly limited. However, in general, the lens frame member is required to be lightweight and easy to process. In the next step, a metal layer made of a metal having a higher ionization tendency than hydrogen is formed on the inner wall surface of the lens frame member, and it is advantageous to employ a plating method as the processing method. . Therefore, in consideration of these, it is desirable to use a plastic material imparted with conductivity as the material of the lens frame member.

  Next, a metal layer is formed on the inner wall surface of such a lens frame member. The metal layer has a higher ionization tendency than hydrogen in order to easily form an oxide layer or a hydroxide layer on the surface. It must be made up of. A metal layer made of a metal or an alloy thereof having a higher ionization tendency than hydrogen is likely to be in the form of an oxide, so that an oxide film is naturally formed if stored in a normal atmosphere. As the metal having a higher ionization tendency than hydrogen, Al, Mg, Zn, etc., which can exist alone, are preferable in consideration of ease of production. Further, when such a metal layer is formed using a plating method, it is possible to evenly coat the inner wall portion having a complicated shape. In this case, the metal cation in the electrolyte solution is immersed in the electrolyte solution in which the metal is made into an aqueous solution by using a lens frame member as a cathode and a plating metal as an anode, and flowing a direct current. This is laminated on the surface of the lens frame member to form a metal layer.

  In this way, after forming the metal layer, an oxide layer is formed on the surface of the metal layer. In this case, the oxide layer may be formed naturally in a normal atmosphere as described above. Is possible. However, the oxide layer may be formed by treating the surface of the metal layer with acid or alkali positively instead of forming the oxide layer naturally. When formed by such treatment, a hydroxide layer having a desired film thickness can be obtained with certainty, so that the formation process of the fine concavo-convex structure layer in the next step can always be performed stably.

  Next, hot water treatment or steam treatment is performed on the oxide layer or hydroxide layer thus formed. When hydrothermal treatment or steam treatment is performed on a metal oxide or hydroxide form, dissolution / reprecipitation occurs in hot water or heated steam from the hydroxide state, and a fine uneven structure layer is formed. The In that case, for example, in a place where the fine uneven structure layer does not need to be formed or a place where it is not desired to be formed, such as a sliding part or a lens fixing part, a desired part can be obtained by processing with a mask. Alternatively, the fine uneven structure layer can be formed only in a desired region.

  The fine concavo-convex structure layer thus formed is extremely suitable for obtaining low reflection characteristics. That is, the fine concavo-convex structure layer has a structure in which the structural unit is at the sub-wavelength level, and the occupied volume increases from the interface side with the air to the lens frame member side. With such a structure, the incident light will feel that the refractive index is gradually changing from the refractive index of air to the refractive index of the substrate, and at the interface with different refractive indexes. It is possible to suppress the reflection that occurs. The fine uneven structure may be a periodic structure in which a certain unit structure is repeated or a random structure.

  Further, the invention according to claim 5 of the present application includes a step of forming an oxide layer or a hydroxide layer on the inner wall surface of a lens frame member processed into a predetermined shape with a metal having a higher ionization tendency than hydrogen, and the oxidation A lens frame member having excellent antireflection properties is manufactured by sequentially performing a hydrothermal treatment or a steam treatment on a physical layer or a hydroxide layer to form a fine relief structure layer. That is, the difference from the invention according to claim 1 is that the lens frame member itself is made of a metal having a higher ionization tendency than hydrogen or a metal made of an alloy thereof. The metal may be any metal as long as it has a higher ionization tendency than hydrogen, but it is desirable to use Al, Zn, or Mg that exists in a simple substance.

  In this case, an oxide layer or a hydroxide layer is formed directly on the inner wall surface without forming the metal layer as described above. For this reason, the number of steps is reduced as compared with the case where the metal layer is formed as described above. After forming the oxide layer or hydroxide layer in this way, the oxide layer or hydroxide layer is subjected to hydrothermal treatment or steam treatment to form a fine relief structure layer. Also in this case, the fine concavo-convex structure layer can be formed only at a desired place in the same manner as in the above case.

  In order to form such a fine concavo-convex structure layer and keep the reflectance of the inner wall surface of the lens frame member low, it is desirable that the film thickness of the fine concavo-convex structure layer be 20 to 300 nm. This is because if the film thickness is less than 20 nm, a sufficient antireflection function cannot be realized, and if it is more than 300 nm, the structure becomes elongated and the mechanical strength becomes weak, and the film tends to break. Here, the film thickness of the fine concavo-convex structure layer refers to the sum of the height of the peak of the convex portion formed on the film surface and the depth of the bottom point of the concave portion, and is defined in JIS B 0601. This corresponds to the maximum height Rz of the contour line, and the film pressure can be measured using an atomic force microscope. It can also be obtained by measurement by cross-sectional observation with a scanning electron microscope.

Hereinafter, four examples of the present invention and one comparative example for the same will be described, but the present invention is not limited to these examples.
In addition, the evaluation method of the anti-reflective film in each Example and a comparative example is as follows.
1. Observation of cross section of film The cross section of the antireflection film was observed using a field emission scanning electron microscope (S4700, manufactured by Hitachi, Ltd.).
2. Reflectance measurement Using a lens reflectometer (USPM-RU manufactured by Olympus), the BK7 glass plate was measured as a reference.
3. Reflection on the inner surface of the lens frame A lens lens frame unit for evaluation was assembled by assembling the lens to the manufactured lens frame member. When light was passed through the lens, the light reflected on the inner wall surface of the lens frame member was visually observed.

  First, Example 1 is demonstrated using FIG.1 and FIG.2. FIG. 1 is a cross-sectional view showing a lens frame member manufactured by the manufacturing method of this embodiment in a state where a lens is assembled. FIG. 2 shows only the lens frame member shown in FIG. It is sectional drawing seen from the diagonal right direction. The lens frame member 1 of this example is made by injection molding polycarbonate resin (Iupilon plating grade PL-1 manufactured by Mitsubishi Engineering Plastics Co., Ltd.). The length is 30 mm and the inner diameter is 20 mm. is there. Further, an annular lens support portion 1a is formed on the inner wall, and FIG. 1 shows a lens barrel unit in which the lens 2 is fixed with an adhesive so as to support it. This lens barrel unit is premised on that light enters the lens 2 from the left side of FIG.

  As is clear from FIG. 2, a fine uneven structure layer 1b is formed on the inner wall surface on the right side of the lens support portion 1a. In the present embodiment, the fine uneven structure layer 1b is It formed as follows. First, after the lens frame member 1 in an injection-molded state as described above was washed, a Zn plating process was performed to form a Zn metal layer on the entire surface of the lens frame member 1. Next, after an oxide film layer is formed on the surface of the metal layer by natural standing, the lens support 2 and the inner wall on the left side thereof are masked and exposed to heated steam at 150 ° C. for 30 minutes, and then at 100 ° C. for 30 minutes. The fine uneven structure layer 1b was formed by heat treatment. At this time, since the heated water vapor was applied only to the inner wall side of the lens frame member 1, the fine uneven structure layer was not formed on the outer wall. The film thickness of the formed fine concavo-convex structure layer 1b was about 120 nm.

  The lens frame unit 1 shown in FIG. 1 is assembled with the lens frame member 1 obtained in this manner. In this state, light is passed through the lens 2 and the reflection state is visually observed. As a result, no reflection on the fine concavo-convex structure layer 1b could be confirmed, which was a good result.

  Next, Example 2 will be described with reference to FIGS. 3 and 4. In FIG. 3, the lens frame member manufactured by the manufacturing method of this example is assembled with the lens in the same manner as in FIG. FIG. 4 is a photograph taken by observing a fine concavo-convex structure layer formed on the inner wall surface of the lens frame member with a scanning electron microscope. The lens barrel member 11 of the present embodiment is manufactured by cutting an aluminum material, has a length of 30 mm, and an inner diameter of 20 mm. Further, an annular lens support portion 11a is formed on the inner wall of the lens frame member 11 in the vicinity of the left end in FIG. 3, and another lens support portion 11b is formed in the vicinity of the right end in FIG. Is formed. FIG. 3 shows a lens barrel unit in which the lenses 12 and 13 are fixed with an adhesive so as to be supported by the lens support portions 11a and 11b. This lens barrel unit also assumes that light is incident on the lens 12 from the left side of FIG.

  Further, as shown in FIG. 3, a fine concavo-convex structure layer 11c is formed on the inner wall surface between the two lens support parts 11a and 11b. The uneven structure layer 11c was formed as follows. First, the lens barrel member 11 made by cutting as described above was allowed to stand naturally, and an oxide film layer was formed on the inner wall surface. Thereafter, the inner wall surface is masked except for the region between the lens support portions 11a and 11b, and is exposed to heated steam at 150 ° C. for 30 minutes, and then heat-treated at 400 ° C. for 30 minutes to form the fine relief structure layer 11c. did. In the case of this example, the fine concavo-convex structure layer 11c was formed as shown in FIG. 4, and the film thickness was about 180 nm.

  The lens frame unit shown in FIG. 3 has the lenses 12 and 13 assembled to the lens frame member 11 thus obtained. In this state, light from a point light source is passed through the lens 12. When the reflection state was observed visually, the reflection on the fine uneven structure layer 11c was not confirmed, and the result was good.

  The above FIG. 3 is also incorporated in the description of this embodiment. In other words, the lens frame member 11 used in the present embodiment is made of aluminum and processed into the same shape and dimension as in the second embodiment. And the fine uneven structure layer 11c was formed in the same inner wall surface area | region as the case of Example 2. FIG. Thereafter, the two lenses 12 and 13 were fixed so as to be supported by the two lens support portions 11a and 11b, and evaluated as a lens barrel unit.

  As described above, in the case of Example 2, the lens barrel member 11 made of aluminum was naturally left after cutting, and an oxide film layer was formed on the inner wall surface. However, in the case of this example, the oxide film layer was formed on the inner wall surface by treating with hydrochloric acid instead of leaving it naturally. The subsequent specific steps were substantially the same as in Example 2, and the film thickness of the fine uneven structure layer 11c formed thereby was about 200 nm.

  After the lenses 12 and 13 are assembled to the lens frame member 11 obtained in this way to form a lens lens frame unit, the reflection state is visually observed through the light from the point light source. The reflection at 11c was not confirmed and was a good result.

  The above FIG. 3 is also used for the description of this embodiment. Therefore, the lens frame member 11 used in the present embodiment is also processed to have exactly the same shape and dimension as in the second embodiment. However, the difference from Example 2 is that the lens frame member 11 of Example 2 is manufactured by cutting an aluminum material, whereas the lens frame member 11 of this example is made of a brass material. It was produced by cutting. The subsequent film formation process of the fine concavo-convex structure layer 11c was exactly the same as in Example 2. As a result, the film thickness of the fine concavo-convex structure layer 11c formed on the inner wall surface was about 110 nm.

  When the lenses 12 and 13 are assembled to the lens frame member 11 to form a lens lens frame unit, and the reflection state is visually confirmed through the light from the point light source through the lens 12, reflection on the fine concavo-convex structure layer 11c cannot be confirmed. It was a good result.

Comparative example

  The above FIG. 3 is also incorporated in the description of this comparative example. That is, the lens frame member 11 used in this comparative example is also made of aluminum and processed into the same shape and dimensions as in the second embodiment. And the fine uneven structure layer 11c was formed in the same inner wall surface area | region as the case of Example 2. FIG. Thereafter, the two lenses 12 and 13 were fixed so as to be supported by the two lens support portions 11a and 11b, and evaluated as a lens barrel unit.

  In the case of this comparative example, the fine uneven structure layer 11c was formed as follows. First, an aluminum lens frame member 11 produced by cutting was left to stand, and an oxide film layer was formed on the inner wall surface. Then, except for the region between the lens support portions 11a and 11b, the inner wall surface is masked, exposed to hot water at 50 ° C. for 10 minutes, and then heat treated at 400 ° C. for 30 minutes to form the fine relief structure layer 11c. did. That is, it differs from Example 2 in that it was exposed to hot water at 50 ° C. for 10 minutes. In the case of this comparative example, the film thickness of the formed fine uneven structure layer 11c was about 15 nm.

  After the lenses 12 and 13 are assembled to the lens frame member 11 obtained in this way to form a lens lens frame unit, the reflection state is visually observed through the light from the point light source. The reflection at 11c was confirmed.

  In each of the above-described embodiments, the lens is directly fixed to the lens frame member. However, the lens frame member of the present invention is not limited only to such a configuration. In some cases, the member directly attaching the lens is fixed, and in other cases, the lens is not fixed directly or indirectly, but the member fixing the lens is movably attached.

It is sectional drawing which showed the lens-frame member manufactured by the manufacturing method of Example 1 in the state which assembled | attached the lens. FIG. 2 is a cross-sectional view showing only the lens frame member shown in FIG. 1 as viewed from the diagonally right direction of FIG. 1. It is sectional drawing which showed the lens-frame member manufactured by the manufacturing method of Example 2 in the state which assembled | attached the lens. It is the figure (photograph) which observed and image | photographed the fine concavo-convex structure layer formed in the inner wall surface of the lens-frame member with the scanning electron microscope by the manufacturing method of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Lens frame member 1a, 11a, 11b Lens support part 1b, 11c Fine uneven structure layer 2, 12, 13 Lens

Claims (8)

  Forming a metal layer made of a metal having a higher ionization tendency than hydrogen on the inner wall surface of a lens frame member processed into a predetermined shape with a predetermined material; and converting the surface of the metal layer into an oxide layer or a hydroxide layer The manufacturing method of the lens frame member characterized by performing sequentially the process of forming, and the process of forming a fine concavo-convex structure layer by performing a hot water process or a water vapor process to the said oxide layer or a hydroxide layer.   The method for manufacturing a lens frame member according to claim 1, wherein the metal is any one of Al, Mg, and Zn.   The method for manufacturing a lens frame member according to claim 1, wherein the metal layer is formed by a plating method.   4. The method for manufacturing a lens frame member according to claim 1, wherein the oxide layer or the hydroxide layer is formed by an acid or alkali treatment.   Forming an oxide layer or a hydroxide layer on the inner wall surface of a lens frame member processed into a predetermined shape with a metal having a higher ionization tendency than hydrogen; and hydrothermal treatment or A method of manufacturing a lens frame member, comprising sequentially performing a step of forming a fine relief structure layer by performing a water vapor treatment.   The method for manufacturing a lens frame member according to claim 5, wherein the metal is any one of Al, Mg, and Zn.   The method for manufacturing a lens frame member according to claim 5 or 6, wherein the oxide layer or the hydroxide layer is formed by an acid or alkali treatment.   The method of manufacturing a lens frame member according to any one of claims 1 to 7, wherein the fine concavo-convex structure layer has a thickness of 20 to 300 nm.