JP2019179146A - Optical component, lens unit, and method of manufacturing optical component - Google Patents

Abstract

To provide an optical component with a highly weatherable antifouling coating film.SOLUTION: An optical member comprises a translucent member, and an antifouling coating film 23 formed on a surface of the translucent member or on a functional coating film formed on the translucent member surface. An organofluorine compound used to form the antifouling coating film contains a cyclic perfluoropolymer obtained through cyclopolymerization of perfluoro(alkenyl vinyl ether), for example. The antifouling coating film may have a thickness in a range of 100-1000 nm, inclusive, for example. Preferably, the translucent member is a lens body 21, and the surface of the translucent member is a lens surface 211.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical component, a lens unit, and a method for manufacturing an optical component.

A camera lens used outdoors and / or a transparent cover plate is provided with an antifouling coating to prevent contamination. Japanese Patent Application Laid-Open No. 2017-8268 discloses a surface treatment agent capable of forming a surface treatment layer having water repellency and high friction durability, and a film having antifouling properties using the surface treatment agent. It has also been proposed to form an optical member.
JP 2017-8268 A

  By the way, since the surface treatment layer of Unexamined-Japanese-Patent No. 2017-8268 is inferior in ultraviolet-resistant performance, it cannot maintain antifouling property outdoors for a long period of time.

  The present invention has been made in view of the above problems, and an object thereof is to provide an optical component having an antifouling film having high weather resistance.

  An exemplary optical component of the present invention includes a translucent member and an antifouling coating formed on the surface of the translucent member or on a functional coating formed on the surface. The organic fluorine compound forming the antifouling film is a polymer containing a repeating unit represented by the formula (I).

  The present invention is also directed to a lens unit including the optical component and a method for manufacturing the optical component.

  ADVANTAGE OF THE INVENTION According to this invention, the optical component which has an antifouling film with high weather resistance can be provided.

FIG. 1 is a cross-sectional view showing a part of a lens having an antifouling coating. FIG. 2 is a cross-sectional view of the imaging apparatus. FIG. 3 is a diagram showing a flow of work for forming the antifouling coating. FIG. 4 is a diagram showing the results of a weather resistance test.

  The antifouling coating used in one exemplary embodiment of the present invention is formed of an organic fluorine compound. The organic fluorine compound is a polymer mainly containing the repeating unit represented by the formula (I).

  The molecular weight of the organic fluorine compound is, for example, 150,000 to 300,000 g / mol. Cyclic perfluoropolymers containing the structure of formula (I) are obtained, for example, by cyclopolymerization of perfluoro (alkenyl vinyl ether). As a material containing the repeating unit of the formula (I), for example, trade name: CYTOP (registered trademark) manufactured by Asahi Glass Co., Ltd. can be used.

The organic fluorine compound containing the repeating unit of the formula (I) includes an anchor attached to the base material. Examples of the functional group (anchor group) serving as an anchor include —COOH. In one example, an amino-based silane coupling agent is preliminarily applied to the base material, thereby introducing a functional group containing NH ₂ at the terminal (herein referred to as “R′NH ₂ ”) onto the base material surface. Then, an organic fluorine compound containing the anchor group (herein referred to as “RCOOH”) is applied to the substrate surface, and a reaction of (RCOOH + R′NH ₂ → RCONHR ′ + H ₂ O) occurs. Thereby, an anchor couple | bonds firmly with a base material by a covalent bond. The anchor group is —Si (R ¹ ) _m (R ² ) _3-m (R ¹ is a hydroxyl group or a hydrolyzable group, R ² is a hydrogen atom or a hydrocarbon group, and m is 1 to 3. It may be an integer). Preferred organofluorine compounds do not contain a carbon-oxygen single bond between at least one repeating unit of formula (I) and the anchor. Hereinafter, the carbon-oxygen single bond is represented as “C—O bond”. More preferably, no C—O bond is present in the main chain.

When the antifouling film formed of the organic fluorine compound is irradiated with ultraviolet rays, the C—O bond is relatively easily broken. In the structure of the formula (I), water repellency is maintained because CF ₂ is not separated even when the C—O bond is broken by irradiation with ultraviolet rays. That is, the weather resistance of the antifouling coating is increased. It can also be understood that the C—O bond is present in the side chain. In addition, since there is no C—O bond between the anchor and at least one repeating unit of the formula (I), the at least one repeating unit is hardly separated from the base material. As a result, the weather resistance becomes higher. The organic fluorine compound may contain other repeating units as long as high weather resistance and water repellency are obtained.

  FIG. 1 is a cross-sectional view showing a part of a lens 20 having an antifouling coating. The lens 20 includes a lens body 21, an antireflection coating 22, and an antifouling coating 23. The lens body 21 is a translucent member. The antireflection coating 22 is formed on the lens surface 211 of the lens body 21. The lens surface 211 is a part of the surface of the lens body 21 that functions as a lens. The antifouling coating 23 is formed on the antireflection coating 22. In the lens 20, the antireflection coating 22 exists on the lens surface 211, and the antifouling coating 23 exists on the antireflection coating 22. The antireflection coating 22 is a base material on which the antifouling coating 23 is formed.

The lens body 21 is, for example, glass or plastic. The antireflection coating 22 may be any type, for example, a multilayer film of an inorganic material and / or an organic material. The antifouling film 23 is a film formed of the above-mentioned organic fluorine compound. Since the antifouling coating 23 and the antireflection coating 22 are bonded by an anchor, the antireflection coating 22 preferably has a hydroxyl group (OH group) on the surface. More preferably, the antireflection coating 22 has a structure in which silicon atoms and hydroxyl groups are bonded. Examples of the material of the antireflection coating 22 include TiO ₂ , SiO ₂ , SiN, SiC, and the like.

  Instead of the antireflection coating 22, another functional coating may be provided. Examples of the other functional coating include a buffer coating that reduces stress between the multilayer coatings or between the coating and the translucent member, and a filter coating that blocks light of a specific wavelength. The functional coating may be a laminate of a plurality of types of functional coating elements. Further, the antifouling film 23 may be formed directly on the lens surface 211 without the functional film. In this case, the lens body 21 becomes a base material on which the antifouling coating 23 is formed. As described above, the antifouling coating 23 is formed on the lens surface 211 or on a functional coating formed on the lens surface 211.

  FIG. 2 is a cross-sectional view of the imaging apparatus 1 having the lens 20. The imaging device 1 includes a lens unit 11, an imaging element 12, and a circuit board 13. The lens unit 11 includes a plurality of lenses 200, a diaphragm 31, an infrared filter 32, and a support portion 33. In the present embodiment, the plurality of lenses 200 include the first lens 20 that is the lens 20, the second lens 212, the third lens 213, the fourth lens 214, and the fifth lens 215. As described above, the “lens” is a member that functions as a lens, that is, a lens member in which a layer having a desired function is formed on the lens surface of the lens body as necessary. The layer on the lens surface is a thin film. A lens having negative power is called a “negative lens”, and a lens having positive power is called a “positive lens”. The plurality of lenses 200 are arranged along the optical axis J1. Each lens is an optical component.

  The support unit 33 is a holder that supports the plurality of lenses 200, the diaphragm 31, and the infrared filter 32. The support 33 is also called a “lens barrel” or “barrel”. In the present embodiment, the support portion 33 is made of resin, but is not limited to resin. The first lens 20, the second lens 212, the third lens 213, the diaphragm 31, the fourth lens 214, the fifth lens 215, and the infrared filter 32 are arranged in this order from the object side to the image side along the optical axis J1. Be placed. That is, these components are located on the optical axis J1 in this order. The circuit board 13 is attached to the support portion 33 on the image side of the infrared filter 32. The image sensor 12 is mounted on the circuit board 13. The image sensor 12 is located on the image side of the lens unit 11. An image is formed on the image sensor 12 by the lens unit 11. The image sensor 12 is a two-dimensional image sensor.

  The first lens 20 is fixed to the support portion 33 by caulking. A seal member 34 is disposed between the first lens 20 and the support portion 33. The seal member 34 is, for example, an O-ring. By the first lens 20 and the seal member 34, the opening on the object side of the cylindrical support portion 33 is sealed. The second lens 212, the third lens 213, the diaphragm 31 and the infrared filter 32 are press-fitted into the support portion 33. The fourth lens 214 and the fifth lens 215 are cemented lenses joined by an adhesive. The cemented lens is press-fitted into the support portion 33. The expression “pressed in” is synonymous with “pressed in”.

  The imaging device 1 including the lens unit 11 is preferably used outdoors. The first lens 20 is the outermost component among the plurality of optical components included in the lens unit 11. The aforementioned antifouling film 23 is formed directly on the object-side lens surface 211 of the first lens 20 or indirectly through the antireflection film 22. The second lens 212, the third lens 213, the fourth lens 214, and the fifth lens 215 are made of glass or plastic. The first lens 20 and the second lens 212 are negative meniscus lenses that are convex on the object side. The third lens 213 is a negative meniscus lens that is convex on the image side. The fourth lens 214 is a negative meniscus lens that is convex toward the object side. The fifth lens 215 is a biconvex positive lens.

  As described above, the antifouling coating 23 has high weather resistance and water repellency. In the outdoor lens unit 11, the antifouling coating 23 is provided on the outermost side, so that a preferable antifouling performance can be maintained over a long period of time. The antifouling coating 23 is particularly suitable for the in-vehicle lens unit 11 that requires weather resistance. The optical component provided with the antifouling coating 23 is not limited to a lens, and may be a flat plate. For example, a protective plate is provided on the most object side of the lens unit 11, and the antifouling coating 23 is formed directly on the flat light-transmitting member on the protective plate or indirectly through an antireflection coating. . The material of the flat light transmitting member is the same as that of the lens body 21 described above. As described above, the antifouling coating 23 is formed on the surface of the translucent member or on the functional coating formed on the surface, so that an optical component having antifouling performance for a long time can be obtained. Obtainable. From the viewpoint of adhesion of the antifouling coating 23, the surface of the translucent member or the surface of the functional coating to which the anchor of the antifouling coating 23 adheres preferably contains silicon (Si). Preferably, the transmittance of light in the visible light region of the translucent member is 90% or more.

  Next, the manufacture of optical components will be described. In the following description, the manufacture of the lens will be described, but the same applies to the manufacture of optical components other than the lens. In the present specification, “lens”, “lens body”, and “lens surface” can be read as “optical component”, “translucent member”, and “surface of (translucent member)”, respectively.

  FIG. 3 is a diagram showing a flow of work for forming the antifouling film 23 on the lens surface 211 of the lens body 21 or on the functional film. First, a lens body that is a translucent member is prepared (step S11). A functional coating may be formed in advance on the lens surface of the lens body. Subsequently, a plasma treatment is performed as necessary on the lens surface or functional coating that is the outermost surface (step S12). By plasma treatment, hydroxyl groups and the like are introduced into the outermost surface.

Thereafter, a transparent antifouling film is formed on the lens surface or the functional film (step S13). The antifouling film may be formed by various methods. For example, a solution in which a material containing the structure of the above formula (I) is dissolved in a solvent is prepared as a treatment agent. As the solvent, alcohol, ketone, ether, aromatic hydrocarbon compound, aliphatic hydrocarbon compound, acetate ester and the like are used. Other materials may be added to the solvent. The solvent may also be a mixed liquid of a plurality of types of solvents. In one example, first, a silane coupling agent (primer) is applied on the lens surface or the functional coating. The silane coupling agent is, for example, H ₂ NCH ₂ CH ₂ CH ₂ Si (OCH ₂ CH ₃ ) ₃ , trade name: KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd., trade name: SILA-ACES330 manufactured by Chisso Corporation, etc. Is available. Subsequently, the treatment agent is applied onto the lens surface or the functional coating by dropping the treatment agent onto the lens surface or the functional coating and rotating the lens body. The treatment agent may be applied to the lens surface by immersing the lens body in the treatment agent. Thereafter, the applied treatment agent is solidified by evaporating the solvent by heating or standing, and an antifouling film is formed. In the case of heating (baking), for example, the lens body is held at 60 ° C. for 30 to 60 minutes, and then held at 180 to 250 ° C. for 30 to 60 minutes.

  A lens having an antifouling film having high weather resistance can be obtained by the above treatment. In order to ensure appropriate characteristics of the lens, the thickness of the antifouling coating is preferably 100 nm or more and 1000 nm or less. From the viewpoint of durability, the thickness of the antifouling coating is preferably 100 nm or more, more preferably 200 nm or more, and even more preferably 300 nm or more. From the viewpoint of the optical performance of the lens, the thickness of the antifouling coating is preferably 1000 nm or less, more preferably 850 nm or less, and even more preferably 700 nm or less.

  FIG. 4 is a diagram showing the results of a weather resistance test for an antifouling coating containing the structure of formula (I). In the weather resistance test, changes in the contact angle of water in the antifouling coating were measured while continuously irradiating the antifouling coating with ultraviolet rays having a predetermined intensity. The vertical axis in FIG. 4 indicates the contact angle, and the horizontal axis indicates the ultraviolet irradiation time. In this test, a film formed using a trade name: OPTOOL (registered trademark) manufactured by Daikin Industries, Ltd. was used as a conventional antifouling film, and the test was similarly performed. The line L1 in FIG. 4 shows the change in the contact angle in the antifouling coating containing the structure of the formula (I), and the line L2 shows the change in the contact angle in the conventional antifouling coating. In the conventional antifouling coating, the contact angle becomes significantly smaller as the ultraviolet irradiation time becomes longer, whereas in the antifouling coating containing the structure of formula (I), the contact angle is approximately maintained. Thereby, it turns out that a weather resistance, mainly ultraviolet-ray resistance improves in the antifouling film containing the structure of Formula (I).

  Various modifications can be made to the optical component and the lens unit.

  The number of lenses in the lens unit 11 may be arbitrarily determined. The optical axis J1 is not limited to a straight line and may be bent. The support portion 33 does not need to hold the entire outer periphery of the lens, and may hold a part of the outer periphery. The lens may be supported by the support 33 while being held by another holder. The imaging device 1 may be used for purposes other than in-vehicle use. The optical component and the lens unit on which the antifouling film 23 is formed may be used in addition to the imaging device 1.

  The configurations in the above embodiment and each modification may be combined as appropriate as long as they do not contradict each other.

  The optical component and the lens unit according to the present invention can be used not only for in-vehicle use but also for various applications.

DESCRIPTION OF SYMBOLS 11 Lens unit 20,212-215 Lens 21 Lens main body 22 Antireflection coating 23 Antifouling coating 33 Support part 211 Lens surface S11-S13 Step

Claims (8)

A translucent member;
An antifouling coating formed on the surface of the translucent member or on a functional coating formed on the surface;
With
The organic fluorine compound forming the antifouling film is

An optical component, which is a polymer containing a repeating unit represented by:   2. The optical component according to claim 1, wherein the organic fluorine compound does not include a carbon-oxygen single bond between the anchor attached to the surface or the functional coating and at least one repeating unit of the formula (I). .   The optical component according to claim 1, wherein the antifouling coating has a thickness of 100 nm to 1000 nm. The translucent member is a lens body;
The optical component according to claim 1, wherein the surface is a lens surface.   The optical component according to any one of claims 1 to 4, which is an outermost component among a plurality of optical components included in a lens unit used outdoors. A plurality of optical components including the optical component according to claim 5;
A support portion for supporting the plurality of optical components;
A lens unit. a) preparing a translucent member;
b) forming an antifouling coating on the surface of the translucent member or on the functional coating formed on the surface;
With
The organic fluorine compound forming the antifouling film is

The manufacturing method of the optical component which is a polymer containing the repeating unit shown by these.   The method for manufacturing an optical component according to claim 7, further comprising a step of performing a plasma treatment on the surface or the functional coating before the step b).

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