JP2019109502A - Optical element, manufacturing method of the same, imaging apparatus, and optical instrument - Google Patents

Abstract

To provide an optical element using an antireflection film with a layer including a rugged structure or a porous layer, capable of preventing performance deterioration of the antireflection film caused by SOcontained in exhaust gas.SOLUTION: There are provided an optical element in which when a surface of the antireflection film is measured by TOF-SIMS, a peak of CmHnN(m is an integer of 1 or more and 8 or less, and n is an integer of 2 or more and 16 or less) is present in a positive ion spectrum, and a manufacturing method of the optical element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical element such as a lens, a method of manufacturing an optical element, an imaging device, and an optical apparatus.

  It is known that an antireflective structure using a fine uneven structure having a wavelength equal to or less than the wavelength of a visible light region exhibits excellent antireflective performance in a wide wavelength range by forming a fine structure of an appropriate pitch and height. There is.

  As a method of forming a fine periodic structure, application of a film in which fine particles having a particle diameter of the visible light wavelength or less are dispersed is known. In addition, the method of forming a fine periodic structure by pattern formation by a microfabrication apparatus such as an electron beam drawing apparatus, a laser interference exposure apparatus, a semiconductor exposure apparatus, and an etching apparatus can control pitch and height, and is excellent. It is known that a fine periodic structure having anti-reflection properties can be formed.

  Furthermore, it is also known that boehmite which is a hydroxide oxide of aluminum is grown on a substrate to obtain an antireflective effect. In these methods, the surface of the aluminum oxide (alumina) film formed by vacuum deposition method or liquid phase method (sol-gel method) is treated with steam or immersed in hot water to form a fine structure by boehmiteing the surface layer, I have obtained an antireflective film. In particular, it is known that the method of forming an antireflective film using the fine structure of boehmite has extremely low reflectance for normal incidence and oblique incidence, and excellent antireflective performance can be obtained (Patent Document 1).

  The antireflective film having a fine structure manufactured by these methods has limitations in control of the structure and size. Therefore, various devices have been made to further enhance the antireflective performance. For example, an intermediate refractive index layer is provided to optimize the refractive index structure and to suppress the influence of the glass material, and a phosphate compound or a carboxylic acid compound is contained in the aluminum oxide layer to prevent contamination from the external environment. A method is known (Patent Document 2).

JP 2005-275372 A JP, 2013-228728, A

However, in recent years, more severe product performance such as quality stability at the time of production and fluctuation suppression by various environmental tests is required. Above all, in an urban area where a large amount of exhaust gas is emitted from a car, the performance deterioration of the anti-reflection film due to SO ₂ contained in the exhaust gas becomes a problem by being continuously exposed to the external environment for a long time. In the phosphate compound and the carboxylic acid compound which are the prior art, the effect of suppressing the performance deterioration of the antireflective film by the exhaust gas is low.

  The present invention has been made in view of such conventional problems, and it is an object of the present invention to provide an optical member having good optical characteristics even in a use environment where exhaust gas adversely affects, and a method of manufacturing the same. With the goal.

The optical element of the present invention is an optical element in which an antireflective film having a layer having a concavo-convex structure or a porous layer is provided on a substrate, and the surface of the antireflective film is measured by TOF-SIMS. In the positive ion spectrum, a peak of CmHnN ⁺ (m is an integer of 1 to 8; n is an integer of 2 to 16) is present.
The method for producing an optical element according to the present invention comprises the steps of forming an antireflection film having a layer having a concavo-convex structure or a porous layer on a substrate, and then using an organic amine compound to obtain CmHnN ⁺ (m is 1 Attaching a component derived from an integer of 8 or less and n is an integer of 2 or more and 16 or less to the surface of the antireflective film.
An image pickup apparatus according to the present invention is characterized by including an image pickup element for receiving light which has passed through the above-mentioned optical element.
The optical apparatus of the present invention is characterized in that an image is generated by the light passing through the above-mentioned optical element.

  According to the present invention, it is possible to provide an optical element having good exhaust gas resistance in an optical element in which an antireflective film using a fine uneven structure is formed.

It is a schematic diagram showing one embodiment of the optical element of the present invention. It is a figure which shows typically the cross section of one Embodiment of the optical element of this invention. It is the schematic explaining the relationship between the uneven structure containing the crystal | crystallization of the aluminum oxide in embodiment of the optical element of this invention, and a base material. It is process drawing which shows one Embodiment of the manufacturing method of the optical element of this invention. It is a schematic diagram showing one embodiment of the optical element of the present invention. It is a schematic diagram showing one embodiment of the optical element of the present invention. It is a schematic diagram showing one embodiment of an imaging device of the present invention. It is a schematic diagram showing one embodiment of an imaging device of the present invention.

  An object of the present embodiment is to provide an optical member having good optical characteristics even in a use environment where exhaust gas adversely affects, and a method of manufacturing the same.

  According to the present embodiment, in the optical element in which the antireflective film using the fine concavo-convex structure is formed, it is possible to provide an optical element having good exhaust gas resistance.

Hereinafter, embodiments of the present invention will be described in detail.
As described above, the optical element of the present invention is an optical element in which an antireflective film having a layer having a concavo-convex structure or a porous layer is provided on a base material, and the surface of the antireflective film is TOF-SIMS When measured by the above, it is characterized in that a peak of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) is present in the positive ion spectrum.
Further, in the method of producing an optical element of the present invention, a step of forming an antireflective film having a layer having a concavo-convex structure or a porous layer on a substrate, and then using an organic amine compound, CmHnN ⁺ (m And a step of attaching a component derived from an integer of 1 to 8 and an integer of 2 to 16) on the surface of the antireflective film.

(Base material)
Examples of the substrate 1 used in the optical member of the present invention include glass, plastic substrates, glass mirrors, plastic mirrors and the like.

  Examples of the glass material include alkali-containing glass, alkali-free glass, alumina silicate glass, borosilicate glass, barium-based glass, lanthanum-based glass, titanium-based glass, fluorine-based glass and the like.

  Representative examples of plastic substrates include polyester, triacetyl cellulose, cellulose acetate, polyethylene terephthalate, polypropylene, polystyrene, polycarbonate, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride and other thermoplastic resins Examples thereof include resin films and molded articles; crosslinked films and crosslinked molded articles obtained from various thermosetting resins such as unsaturated polyester resins, phenol resins, crosslinked polyurethanes, crosslinked acrylic resins, and crosslinked saturated polyester resins.

  Although the case of a flat plate is shown in FIG. 1 as the substrate 1, the present invention is not limited to this. For example, an optical member having a shape such as a biconvex lens, a planoconvex lens, a convex meniscus lens, a biconcave lens, a planoconcave lens, a concave meniscus lens, an aspheric lens, and a free curved lens may be used.

First Embodiment
(Antireflection film having a layer having a concavo-convex structure to which an organic amine compound is attached)
An optical element according to an embodiment of the present invention is an optical element in which an antireflective film is formed on the surface of a base material, and the outermost layer of the antireflective film has a crystal layer having a concavo-convex structure containing aluminum oxide crystals. Have. The surface of the crystal layer has a concavo-convex structure (protrusion structure). And, an organic amine compound is contained in a part or all of the crystal layer.

  FIG. 1 is a schematic view showing an embodiment of the optical element of the present invention. The optical element of the present embodiment is an optical element in which an antireflective film 10 is formed on the surface of a flat substrate 1. In FIG. 1, the optical element of the present embodiment is provided with a crystal layer 2 having a concavo-convex structure including a crystal of aluminum oxide on the surface of a base material 1. The uneven structure has a large number of protrusions 6. The crystal layer 2 having the concavo-convex structure contains the organic amine compound 3. The antireflective film 10 is composed of a crystal layer 2.

  The inclusion of the organic amine compound in a part of the crystal layer 2 having the above-mentioned concavo-convex structure is, for example, scattered on a part of the surface of the crystal layer 2 and / or inside the crystal layer 2 as shown in FIG. It says that it exists to the middle of the direction to the base material 1. Moreover, you may contain the organic type amine compound over the whole of the crystal layer 2 which has the said uneven structure.

  The crystal layer 2 having a concavo-convex structure used in the present embodiment is a nano structure of a specific material, and the apparent refractive index lower than the refractive index inherent to the material changes in the thickness direction of the film. It is a protection film. The specific material is preferably, for example, aluminum oxide.

  The concavo-convex structure is specifically realized by a fine structure having a dimension shorter than the used wavelength of the optical component in which the antireflective film is used. The microstructure has therein a plurality of closed spaces closed from the external atmosphere and / or open spaces released to the external atmosphere. As a result, the refractive index (refractive index specific to the material) of the material constituting the antireflective film and the refractive index of the medium such as air which occupies space (fills) are averaged. Thereby, the antireflective film has a refractive index lower than the refractive index (refractive index unique to the material) of the material constituting the antireflective film, and the apparent refractive index as the antireflective film is lowered. Can. In other words, the refractive index specific to a material is the refractive index of the non-porous thin film or bulk of the material, and the apparent refractive index is the refractive index of the microstructural film that has become low due to having space. is there.

  The apparent refractive index can be changed by changing the occupancy of the space in the antireflective film or the occupancy of the solid portion in the film thickness direction.

  FIG. 2 is a view schematically showing a cross section of the antireflective film used in the embodiment of the present invention, and has a solid portion (protrusion) 6 and a space 11. It is preferable to increase the apparent refractive index intermittently or continuously along the light traveling direction (arrow A) from the light incident side. Alternatively, it is preferable to decrease the apparent refractive index intermittently or continuously along the light traveling direction (arrow B) from the light incident side. In particular, the outermost surface of the antireflective film in contact with the external atmosphere has a refractive index close to 1, and the refractive index specific to the material constituting the antireflective film increases as the outermost surface gets deeper in the film thickness direction of the antireflective film It is preferable to have the optical property that the refractive index gradually increases so as to approach the rate (e.g., 1.4 to 3.0).

  The antireflective film may have a structure in which at least two layers of fine structures having different occupancy rates in space or solid portion are stacked, or have distribution such that the occupancy rate in space or solid portion is different. And, on the outermost surface side of the antireflective film, the space communicates with the external atmosphere, thereby having a fine uneven structure that is not smooth, and the thickness (t) of the convex portion (protrusion) is the use of the element It has a size smaller than the wavelength, specifically in the nanometer order.

(Relationship between fine asperity structure and base material)
In the said embodiment, the crystal of the aluminum oxide which comprises the crystalline layer 2 which has uneven structure is formed of the oxide or hydroxide of aluminum, or those hydrates. Particularly preferred crystals are boehmite. Also, by arranging these crystals, the end portions form fine projections, so that the height of the projections can be increased and the spacing can be narrowed, the crystals are selectively selective to the surface of the substrate. Placed at a specific angle.

  FIG. 3 is a schematic view illustrating the relationship between a concavo-convex structure including a crystal of aluminum oxide and a substrate in the embodiment of the present invention. When the surface of the substrate 1 is a flat surface, such as a flat plate, a film or a sheet, as shown in FIG. 3A, the protrusions 6 are inclined relative to the substrate surface 8 in the inclination direction 7 of the protrusions 6 and the substrate surface 8 It is desirable that the average angle of the angle θ1 formed by the edges be 45 ° or more and 90 ° or less, preferably 60 ° or more and 90 ° or less.

  In addition, when the surface of the substrate 1 has a two-dimensional or three-dimensional curved surface, as shown in FIG. 3B, the protrusions 6 have an inclination direction 7 of the protrusions 6 with respect to the surface of the substrate and the substrate Desirably, the average angle of the angle θ2 formed by the tangent line 9 of the surface 8 is 45 ° or more and 90 ° or less, preferably 60 ° or more and 90 ° or less. In addition, although the value of said angle (theta) 1 and (theta) 2 may exceed 90 degrees by the inclination of protrusion, it is set as the value measured on the conditions which become 90 degrees or less in this case.

  The layer thickness of the crystal layer 2 having the above-mentioned concavo-convex structure is preferably 20 nm or more and 1000 nm or less, and more preferably 50 nm or more and 1000 nm or less. When the layer thickness of the crystal layer 2 having the concavo-convex structure is 20 nm or more and 1000 nm or less, the antireflection performance by the concavo-convex structure is effectively exhibited, and there is no possibility that the mechanical strength of the projections is impaired. Can also be reduced. Further, by setting the layer thickness to 50 nm or more and 1000 nm or less, the antireflection performance is further enhanced, which is more preferable.

Moreover, another intermediate layer can also be formed between the anti-reflection film and the base material of such a fine uneven structure (projection). As such an intermediate layer, a solid film having a refractive index intermediate between the apparent refractive index of the antireflective film and the refractive index of the substrate is preferably used. Specifically, it is an inorganic substance such as a metal compound such as SiO ₂ , TiO ₂ , ZrO ₂ , ZnO, or Ta ₂ O ₅ used as a material of an antireflective film, or an organic substance such as a resin represented by polyimide possible.

(Organic amine compounds)
Since the crystal layer having a fine uneven structure is porous, harmful gases such as SO ₂ contained in the exhaust gas are easily absorbed inside when exposed to an environment with a high exhaust gas concentration for a long time. Then, problems such as changes in characteristics such as the refractive index of the entire crystal layer and the occurrence of fogging in the appearance easily occur.

The organic amine compound 3 in the present invention functions to absorb SO ₂ and has a weakly alkaline property. It is considered that the presence of an appropriate amount of this compound on the outermost surface of the crystal layer has the effect of blocking the penetration of SO ₂ into the inside of the crystal layer and suppressing the change of the weakly acidic crystal layer. However, if a large amount of the organic amine compound is attached, the amine compound itself becomes contaminated and adversely affects the reflectance performance.

The abundance of the organic amine compound can be calculated from TOF-SIMS analysis (time-of-flight secondary ion mass spectrometry). In the positive ion spectrum obtained by this analysis, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) with respect to the peak intensity of Al ⁺ representing the presence of the crystal layer Is preferably 1E-04 or more, and more preferably 1E-02 or less. More preferably, they are 1.6E-04 or more and 9.5E-03 or less. If the amount is less than 1E-04, the amount of the organic amine compound is too small to exhibit the SO ₂ entry inhibitory effect. On the other hand, if it exceeds 1E-02, the organic amine compound contaminates to adversely affect the transparency and reflectance performance. In the present specification, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) with respect to the peak intensity of Al ⁺ representing the presence of a crystalline layer is As a result, when there are a plurality of peaks corresponding to CmHnN ⁺ , the peak with the largest peak intensity is determined.

(Method of Manufacturing Optical Element Having Antireflection Film Having Layer Having Irregular Structure)
A method of manufacturing an optical element according to an embodiment of the present invention is a method of manufacturing an optical element in which an antireflective film is formed on the surface of a substrate, and includes the following three steps A, B, and C. And

A. Forming an aluminum oxide layer containing aluminum oxide on a substrate;
B. A step of contacting the aluminum oxide layer with warm water or water vapor at 60 ° C. or more and 100 ° C. or less to form a crystal layer having a concavo-convex structure;
C. Depositing an organic amine compound on the crystalline layer;

FIG. 4 is a process diagram showing an embodiment of a method of manufacturing an optical element of the present invention.
The above-mentioned crystal layer of aluminum oxide means that the surface layer of the aluminum oxide film is subjected to a peptizing action etc. by bringing the film containing aluminum oxide into contact with warm water or steam, and the crystal layer 2 is deposited and grown on the surface layer of the film. The form is a fine uneven structure. In the crystal layer 2 having a concavo-convex structure, crystals of various sizes are randomly disposed, and the upper end portion forms a protrusion. Therefore, it is necessary to control the deposition and growth of crystals in order to change the height and size of the protrusions, the angle, and the distance between the protrusions.

  FIG. 4A shows a step A of forming an aluminum oxide layer 5 containing aluminum oxide on a substrate 1.

  The surface of the anti-reflection film 10 having a concavo-convex structure in the present invention is a concavo-convex shape due to a plate-like crystal film. This plate-like crystal is formed by immersing a film containing aluminum in warm water, whereby the surface of the film containing aluminum is dissolved and reprecipitated.

  The film containing aluminum described above is a film mainly composed of aluminum oxide formed by a sol-gel method or the like, or metal aluminum formed by a known CVD method, or vapor phase growth method such as PVD method such as vapor deposition or sputtering. It may be a film, or a metal film or an oxide film containing aluminum metal.

  Moreover, as a raw material of the film | membrane which contains the said aluminum, you may use the mixture of each compound of zirconium, silicon, titanium, and zinc, and an aluminum compound. As raw materials of zirconia, silica, titania, zinc oxide and alumina, respective metal alkoxides and salt compounds such as chloride and nitrate can be used. From the viewpoint of film formability, it is particularly preferable to use metal alkoxides as zirconia, silica and titania.

  FIG.4 (b) shows the process B which makes the said aluminum oxide layer 5 contact warm water or water vapor | steam, and forms the crystal layer 2 which has an uneven | corrugated structure. By contacting the surface of the aluminum oxide film with warm water, crystals of aluminum oxide are formed. The hot water is brought into contact with the hot water for 5 minutes to 24 hours and then dried at a temperature of 60 ° C. to 100 ° C.

  As such a method, for example, methods described in JP-A-2006-259711, JP-A-2005-275372 and the like can be used.

  The optical element of the present invention can further have a film for providing various functions in addition to the films described above. For example, a single layer or a plurality of layers may be provided as an intermediate layer between the substrate and the antireflective film. This makes it possible to further improve the anti-reflection performance.

As such an intermediate layer, a solid film having a refractive index intermediate between the apparent refractive index of the antireflective film and the refractive index of the substrate is preferably used. Specifically, it is an inorganic substance such as a metal compound such as SiO ₂ , TiO ₂ , ZrO ₂ , ZnO, or Ta ₂ O ₅ used as a material of an antireflective film, or an organic substance such as a resin represented by polyimide possible.

FIG. 4C shows a step C of attaching the organic amine compound 3 onto the crystalline layer 2.
In the present invention, the organic amine compound 3 deposited on the crystalline layer 2 is preferably selected from curing agent materials containing a ketimine derivative. Specifically, Mitsubishi Chemical Co., Ltd. hardening agent jER cure H30 (brand name), ADEKA Co., Ltd. hardening agent EH-235R-2 (brand name) etc. are mentioned. A curing agent having a ketimine group tends to hydrolyze with water to form an amine. Therefore, an amine having an aliphatic hydrocarbon group of a suitable length in a side chain is formed and attached to the surface of the crystal layer. And, it does not react with aluminum oxide, which is the main component of the crystal layer, and exhibits the ability to adsorb harmful substances in exhaust gas such as SO ₂ .

  In order to adhere to the surface of the crystal layer, these materials may be used alone or in combination with solvents or resins. In addition, in order to deposit the organic amine compound on the crystal layer, the crystal layer is enclosed in a container together with a hardener material, and then the whole container is heated in an oven or the like, or the hardener material is heated. There is a method of attaching the volatilized organic amine compound to the surface of the crystal layer, or a method of directly coating a curing agent material diluted in a solvent. As a direct coating method, a spin coating method, a dip coating method, a spray coating method or the like is desirable. However, since the amount of adhesion must be very small, in the case of volatilization, it is necessary to volatilize a small amount at a low temperature of 100 ° C. or less, and in the case of coating, dilution to a low concentration.

  Moreover, in the manufacturing method according to the present invention, a step of forming an intermediate refractive index layer can be provided before forming the aluminum oxide layer on the base material.

  FIG. 5 schematically shows an example of an optical member in which an intermediate refractive index layer 4 is provided between a base material 1 and a crystal layer 2 having a concavo-convex structure including crystals of aluminum oxide. In this case, the antireflective film 10 on the substrate 1 is composed of the intermediate refractive index layer 4 and the crystal layer 2.

  In the optical member having the intermediate refractive index layer 4 between the base 1 and the crystal layer 2 described above, the refractive index nb of the base 1, the refractive index ni of the intermediate refractive index layer 4, and the crystal of aluminum oxide It is preferable that the refractive index ns of the crystal layer 2 having the concavo-convex structure to be included has a relationship of nb> ni> ns.

The intermediate refractive index layer 4 is preferably a transparent film made of an inorganic material or an organic material. Examples of such inorganic materials include metal oxides such as SiO ₂ , TiO ₂ , ZrO ₂ , ZnO, Ta ₂ O _{5 and the} like. Examples of the method for forming the intermediate refractive index layer 4 made of an inorganic material include a vacuum film forming method such as vapor deposition and sputtering, and a sol-gel method by application of a metal oxide precursor sol.

  Examples of the above organic materials include acrylic resin, epoxy resin, oxetane resin, maleimide resin, melamine resin, benzoguanamine resin, phenol resin, resole resin, polycarbonate, polyester, polyarylate, polyether, polyurea, polyurethane, polyamide, polyamide Polymers such as imide, polyimide, polyketone, polysulfone, polyphenylene, polyxylylene, polycycloolefin and the like can be mentioned.

As a method of forming the middle refractive index layer 4 made of an organic material, a wet coating method of forming a film mainly by coating of the solution may be mentioned.
Moreover, when producing an intermediate-refractive-index layer by a wet process, you may add a drying process suitably.

Second Embodiment
(Antireflective film having porous layer to which organic amine compound is attached)
A second embodiment of the present invention will be described with reference to FIG. In FIG. 6, 1 is a substrate, 12 is a porous layer, and 3 is an organic amine compound. The optical element according to the second embodiment of the present invention shown in FIG. 6 has a porous layer 12 in place of the crystal layer 2 (see FIG. 4) having the concavo-convex structure described in the first embodiment. It is. The same effect can be obtained by using a porous layer instead of the layer having the concavo-convex structure. This embodiment is the same as the first embodiment except that the porous layer 12 is used in place of the crystal layer 2 having the concavo-convex structure, and the detailed description will be omitted. Examples of the porous layer include a layer in which fine particles of silicon oxide and hollow particles are deposited. A dispersion in which such particles are dispersed in water or a solvent can be applied by spin coating or the like, in which case the density of the film is reduced by the voids formed between the particles, and a low refractive index layer can be formed. The layer thickness of the porous layer is preferably 30 nm or more and 300 nm or less, and more preferably 50 nm or more and 200 nm or less.

The abundance of the organic amine compound 3 can be calculated from TOF-SIMS analysis (time-of-flight secondary ion mass spectrometry). In the positive ion spectrum obtained by this analysis, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) with respect to the peak intensity of Si ⁺ representing the presence of a crystalline layer Is preferably 1E-04 or more, and more preferably 1E-02 or less. If the amount is less than 1E-04, the amount of the organic amine compound is too small to exhibit the SO ₂ entry inhibitory effect. On the other hand, if it exceeds 1E-02, the organic amine compound contaminates to adversely affect the transparency and reflectance performance. In the present specification, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) with respect to the peak intensity of Si ⁺ representing the presence of a crystalline layer means As a result, when there are a plurality of peaks corresponding to CmHnN ⁺ , the peak with the largest peak intensity is determined.

Third Embodiment
FIG. 7 shows the configuration of a single-lens reflex digital camera which is an example of a preferred embodiment of the imaging device of the present invention to which a lens barrel (interchangeable lens) which is an example of the optical device of the present invention is coupled. FIG. 8 shows the configuration of a network camera, which is an example of a preferred embodiment of the imaging device of the present invention.

  The optical apparatus of the present invention refers to an apparatus provided with an optical system including the optical element of the present invention, such as binoculars, a microscope, a semiconductor exposure apparatus, an interchangeable lens, and the like. Or the thing of the apparatus which produces | generates an image by the light which passed the optical element of this invention.

  Further, the imaging device of the present invention refers to an electronic device including a camera system such as a digital still camera or a digital video camera, or an imaging device that receives light passing through the optical element of the present invention such as a cellular phone. Note that there is also a case where a module form mounted on an electronic device, for example, a camera module is used as an imaging device.

  In FIG. 7, the camera 600 is configured by combining a camera body 602 and a lens barrel 601 that is an optical device, but the lens barrel 601 is a so-called interchangeable lens that can be attached to and detached from the camera body 602.

  The light from the subject passes through an optical system including a plurality of lenses 603 and 605 disposed on the optical axis of the imaging optical system in the housing 620 of the lens barrel 601, and is received by the imaging device. The optical element of the present invention can be used, for example, for the lens 603.

  Here, the lens 605 is supported by the inner cylinder 604 and is movably supported with respect to the outer cylinder of the lens barrel 601 for focusing and zooming.

  In the observation period before shooting, light from the subject is reflected by the main mirror 607 in the housing 621 of the camera body, passes through the prism 611, and then the shot image is projected to the photographer through the finder lens 612. The main mirror 607 is, for example, a half mirror, and the light transmitted through the main mirror is reflected by the sub mirror 608 toward the AF (autofocus) unit 613. For example, the reflected light is used for distance measurement. The main mirror 607 is mounted and supported on the main mirror holder 640 by adhesion or the like. At the time of photographing, the main mirror 607 and the sub mirror 608 are moved out of the optical path via a drive mechanism (not shown), the shutter 609 is opened, and the photographing light image incident from the lens barrel 601 is formed on the imaging element 610. Further, the stop 606 is configured to be able to change the brightness and the depth of focus at the time of shooting by changing the aperture area.

  FIG. 8A is an external view of a network camera which is an example of the imaging apparatus of the present invention, and FIG. 8B is an exploded perspective view of the network camera shown in FIG. In the present embodiment, as an example of the network camera, an image monitoring system is configured to be communicably connected to a server (monitoring apparatus) such as an external image monitoring center by wireless or wire and monitor the captured image on the server side. Although a network camera is illustrated, application of the present invention is not limited thereto.

  In the network camera of the present embodiment, as shown in FIG. 8, an imaging unit 200 is provided inside an exterior cover formed of an upper cover 103, a lower cover 102, and a dome-shaped cover 101 (hereinafter referred to as a dome cover 101). It is provided. The imaging unit 200 has an optical system (not shown) composed of a plurality of lenses and an imaging element (not shown) for receiving light passing through the optical system. The dome cover 101 is a substantially hemispherical transparent member disposed on the front side (subject side) of the image captureable range of the imaging unit 200 and protecting an optical system (not shown) included in the imaging unit 200. The antireflective film of the present invention may be provided on the dome-shaped cover 101, or may be provided on at least one of the lenses constituting the optical system (not shown) included in the imaging unit 200. When provided on at least one of the lenses constituting the optical system (not shown), the effect of the present invention can be obtained more prominently if provided on the outermost side (the lens farthest from the imaging device) it can.

  Next, the present invention will be described in detail by way of examples. However, the present invention is not limited to such examples.

  In addition, performance evaluation was performed by the following method about the anti-reflective film which has the fine concavo-convex structure obtained by each Example and the comparative example.

(Performance evaluation)
About monitor glass which formed anti-reflective film, evaluation of appearance after exhaust gas test (we confirm existence of fog generation visually) and reflectance evaluation before and after exhaust gas test (absolute reflectance measuring device (USPM-RU) (The trade name) manufactured by Olympus Corporation was used to measure the reflectance when the incident angle of light in the wavelength range of 400 nm to 700 nm was 0 °.

  For the appearance evaluation, it was C when fogging occurred and A when it did not occur. For the evaluation of reflectance, an average value of reflectance at a wavelength of 400 nm to 700 nm was taken as an average reflectance, and when the numerical value was 0.3 or less, it was B, and when it was larger than 0.3, it was D.

Example 1
(Formation of antireflective film having an uneven structure)
As a monitor glass for evaluation, the material is S-LaH55 (nd = 1.83; manufactured by OHARA INC.), And the shape having a diameter of 30 mm and a thickness of 1 mm was used.

  The monitor glass was subjected to ultrasonic cleaning in an alkaline detergent and then dried in an oven. Thereafter, an appropriate amount of aluminum oxide precursor sol was dropped on the monitor glass surface, and spin coating was performed for 20 seconds at a rotational speed of 3000 rpm. Thereafter, the resultant was baked in a hot air circulating oven at 140 ° C. for 30 minutes to coat an amorphous aluminum oxide film. Then, the sample in which the anti-reflective film which has a fine concavo-convex structure containing the crystal | crystallization of aluminum oxide on the surface of monitor glass was obtained by being immersed in 75 degreeC warm water for 20 minutes.

(Adhesion of organic amine compounds)
As an amine-based curing agent material, 1.0 g of curing agent jER Cure H30 (trade name) manufactured by Mitsubishi Chemical Corp. was weighed in an aluminum foil cup, and sealed together with the sample in a large petri dish. Thereafter, the large petri dish was subjected to heat treatment at 90 ° C. for 2 hours in an oven. By this treatment, the organic amine compound volatilized from the curing agent adhered to the surface of the antireflective film.

(Exhaust gas test)
The sample was sealed in a space adjusted to 5 ppm SO ₂ concentration based on the CSE standard, and placed in an environment of temperature 25 ° C. and humidity 65% for 10 hours.

(Performance evaluation)
The appearance of the sample after the exhaust gas test showed no fogging.
The average reflectance before the exhaust gas test of the sample was 0.06, and the average reflectance after the test was 0.09.

(Measurement of the abundance of CmHnN ⁺ )
The TOF-SIMS analysis was performed about the sample surface, the peak corresponding to Al ^<+> and CmHnN ^<+> was selected from the obtained positive ion spectrum, and ratio of the peak intensity was computed. The measurement conditions are shown below. Device: ION-TOF TOF-SIMSIV; Primary ion: Ga ⁺ ; Acceleration voltage: 25 kV

As a result of TOF-SIMS analysis, the largest peak among the CmHnN ⁺ peaks of interest was C6H12N ⁺ , and the peak intensity was 4.0E + 03. Moreover, the peak intensity of Al ^<+> was 5.0E + 05, CmHnN ^<+ > / Al ^<+> was 8.0E-03.

Example 2
In Example 2, a sample is produced under the same conditions as in Example 1 except that the amine-based curing agent material used is replaced with curing agent EH-235R-2 (trade name) manufactured by ADEKA Corporation, and performance evaluation is performed. Did.

The appearance of the sample after the exhaust gas test showed no fogging.
The average reflectance before the exhaust gas test of the sample was 0.12, and the average reflectance after the test was 0.18.

As a result of TOF-SIMS analysis, the largest peak among the CmHnN ⁺ peaks of interest was C 3 H ⁶ N ⁺ , and the peak intensity was 2.1E + 03. Moreover, the peak intensity of Al ^<+> was 2.2E + 05, CmHnN ^<+ > / Al ^<+> was 9.5E-03.

[Example 3]
Example 3 is the same as Example 1 except that an appropriate amount of a solution prepared by mixing 0.5 g of jER cure H30 with 100 g of PGME is dropped on the monitor glass surface and the rotation speed is 4000 rpm for 20 seconds. Samples were prepared under conditions and operation, and performance evaluation was performed.

The appearance of the sample after the exhaust gas test showed no fogging.
The average reflectance before the exhaust gas test of the sample was 0.15, and the average reflectance after the test was 0.21.

As a result of TOF-SIMS analysis, it was the peak C6H12N ⁺ which is the largest among the CmHnN ⁺ peaks to be targeted, and the peak intensity was 6.0E + 01. Moreover, the peak intensity of Al ^<+> was 3.8E + 05, CmHnN ^<+ > / Al ^<+> was 1.6E-04.

Example 4
In Example 4, the antireflective film was formed not by wet coating of the sol-gel film but by sputtering film formation. Specifically, aluminum was used as a target, Ar gas and O ₂ gas were respectively flowed at 10 sccm, the film forming pressure was 0.4 Pa, and 300 W was applied with a DC power supply to form a film for 50 minutes. Other than that, the sample was produced on conditions and operation similar to Example 1, and performance evaluation was performed.

The appearance of the sample after the exhaust gas test showed no fogging.
The average reflectance before the exhaust gas test of the sample was 0.07, and the average reflectance after the test was 0.10.

As a result of TOF-SIMS analysis, the largest peak among the CmHnN ⁺ peaks of interest was C6H12N ⁺ , and the peak intensity was 3.8E + 03. Moreover, the peak intensity of Al ^<+> was 6.0E + 05, CmHnN ^<+ > / Al ^<+> was 6.3E-03.

Comparative Example 1
In Comparative Example 1, a sample was produced under the same conditions and procedures as in Example 1 except that the organic amine compound was not attached, and performance evaluation was performed.

The appearance of the sample after the exhaust gas test was cloudy.
The average reflectance before the exhaust gas test of the sample was 0.11, and the average reflectance after the test was 0.62.

As a result of TOF-SIMS analysis, the peak that is the largest among the CmHnN ⁺ peaks of interest was C6H12N ⁺ , and the peak intensity was 4.0E + 01. Moreover, the peak intensity of Al ^<+> was 4.8E + 05, and CmHnN ^<+ > / Al ^<+> was 8.3E-05.

Comparative Example 2
In Comparative Example 2, a sample was produced under the same conditions and operation as in Example 3 except that the amount of the organic amine compound jER cure H30 used was changed to 10 g, and performance evaluation was performed.

The appearance of the sample after the exhaust gas test was cloudy.
The average reflectance before the exhaust gas test of the sample was 0.44, and the average reflectance after the test was 0.46.

As a result of TOF-SIMS analysis, the largest peak among the CmHnN ⁺ peaks of interest was C6H12N ⁺ , and the peak intensity was 3.2E + 05. Moreover, the peak intensity of Al ^<+> was 5.4E + 05, and CmHnN ^<+ > / Al ^<+> was 5.9E-01. The results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown together in Table 1.

  The optical element according to the present invention can be used for camera systems such as digital still cameras and digital video cameras, and imaging devices such as electronic devices having an imaging function such as mobile phones. Moreover, it is possible to use for optical instruments, such as an interchangeable lens, binoculars, a microscope, and a semiconductor exposure device.

DESCRIPTION OF SYMBOLS 1 base material 2 crystal layer 3 organic type amine compound 4 middle refractive index layer 5 aluminum oxide layer 6 protrusion 7 inclination direction 8 base material surface 9 tangent line 10 anti-reflective film 11 space

Claims (10)

An optical element in which an antireflective film having a layer having a concavo-convex structure or a porous layer is provided on a substrate, and when the surface of the antireflective film is measured by TOF-SIMS, CmHnN ^{+ in} positive ion spectrum An optical element having a peak (m is an integer of 1 to 8 and n is an integer of 2 to 16). When the surface of the antireflective film is measured by TOF-SIMS, the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8; n is an integer of 2 to 16) with respect to the peak intensity of Al ⁺ in the positive ion spectrum The optical element according to claim 1, wherein the ratio of is 1E-04 or more. In the positive ion spectrum, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) to the peak intensity of Al ⁺ is 1E-02 or less. The optical element according to claim 2. When the surface of the antireflective film is measured by TOF-SIMS, the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8; n is an integer of 2 to 16) with respect to the peak intensity of Al ⁺ in the positive ion spectrum The optical element according to claim 1, characterized in that the ratio of is between 1.6E-04 and 9.5E-03. When the surface of the antireflective film is measured by TOF-SIMS, the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8; n is an integer of 2 to 16) with respect to the peak intensity of Si ⁺ in the positive ion spectrum The optical element according to claim 1, wherein the ratio of is 1E-04 or more. In the positive ion spectrum, the ratio of the peak intensity of CmHnN ⁺ (m is an integer of 1 to 8 and n is an integer of 2 to 16) to the peak intensity of Si ⁺ is 1E-02 or less. The optical element according to claim 5. Forming an antireflective film having a layer having a concavo-convex structure or a porous layer on a substrate;
Subsequently, using an organic amine compound, attaching a component derived from CmHnN ⁺ (m is an integer of 1 to 8; n is an integer of 2 to 16) to the surface of the antireflective film;
A method of manufacturing an optical element, comprising:   An imaging device comprising: an imaging device that receives light having passed through the optical device according to any one of claims 1 to 6.   An optical apparatus characterized by generating an image by light having passed through the optical element according to any one of claims 1 to 6.   The optical apparatus according to claim 9, which is a camera.

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