阅读说明：本技术 带有亲水性防反射膜的透镜及其制造方法 (Lens with hydrophilic anti-reflection film and method for manufacturing same ) 是由 川岸秀一朗 白石幸一郎 于 2018-05-15 设计创作，主要内容包括：本发明的目的在于提供不会损害防反射效果且具备防雾性的带有亲水性防反射膜的透镜及其制造方法。带有亲水性防反射膜的透镜的特征在于,在玻璃透镜的表面上至少具有按照底膜以及亲水性膜的顺序层叠而成的亲水性防反射膜,底膜由选自ZrO<Sub>2</Sub>、MgF<Sub>2</Sub>、Ta<Sub>2</Sub>O<Sub>5</Sub>、Nb<Sub>2</Sub>O<Sub>5</Sub>、以及Y<Sub>2</Sub>O<Sub>3</Sub>的单层等形成,膜厚为1nm以上30nm以下,亲水性膜在底膜的表面上,通过由TiO<Sub>2</Sub>以及Ti<Sub>3</Sub>O<Sub>5</Sub>中的至少一者构成的氧化钛、或者由TiN构成的氮化钛的单层、或者含有50％以上的氧化钛以及氮化钛中的至少一者的混合层形成,膜厚为1nm以上30nm以下。(The invention aims to provide a lens with a hydrophilic anti-reflection film and a manufacturing method thereof, wherein the lens has an anti-fog property without damaging an anti-reflection effect. The lens with hydrophilic anti-reflection film is characterized in that the surface of the glass lens at least has a hydrophilic anti-reflection film formed by laminating a primary film and a hydrophilic film in the order of, the primary film is selected from ZrO 2 、MgF 2 、Ta 2 O 5 、Nb 2 O 5 And Y 2 O 3 A film thickness of 1nm to 30nm, and a hydrophilic film on the primary filmOn the surface of (2) by reaction with TiO 2 And Ti 3 O 5 A single layer of at least one of titanium oxide and titanium nitride made of TiN, or a mixed layer containing at least 50% of at least one of titanium oxide and titanium nitride, and has a film thickness of 1nm to 30 nm.)

1. A lens having a hydrophilic antireflection film, characterized in that,

a hydrophilic antireflection film formed by laminating at least a base film and a hydrophilic film in this order on the surface of the glass lens,

the bottom film is made of ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅Mixing of more than one of the materials ofForming a layer having a thickness of 1nm to 30nm,

the hydrophilic film is formed on the surface of the base film by TiO₂And Ti₃O₅A single layer of at least one of titanium oxide and titanium nitride made of TiN, or a mixed layer containing at least 50% of at least one of the titanium oxide and the titanium nitride, and has a film thickness of 1nm to 30 nm.

2. The lens with a hydrophilic antireflection film according to claim 1, wherein a porosity of the hydrophilic film is 20% or less.

3. The lens with a hydrophilic antireflection film according to claim 1 or 2,

the hydrophilic anti-reflection film is laminated on the surface of the glass lens in the order of the anti-reflection film, the base film, and the hydrophilic film,

the antireflection film has one or more layers selected from SiO₂、MgF₂、ZrO₂、Al₂O₃、TiO₂、Ti₃O₅、Ta₂O₅And Nb₂O₅Or a mixed layer containing two or more materials.

4. A method for manufacturing a lens having a hydrophilic antireflection film, comprising the steps of:

on the surface of the glass lens by a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅A step of forming a primary coating having a thickness of 1nm to 30nm on the mixed layer of the at least one material;

on the bottom filmOn the surface of (2) by reaction with TiO₂And Ti₃O₅A single layer of titanium oxide or titanium nitride made of TiN, or a mixed layer containing 50% or more of at least one of the titanium oxide and the titanium nitride, thereby forming a hydrophilic film having a thickness of 1nm to 30 nm.

5. The method of manufacturing a lens with a hydrophilic antireflection film according to claim 4, wherein the base film and the hydrophilic film are formed by a vapor deposition method or a sputtering method.

6. The method for producing a lens with a hydrophilic antireflection film according to claim 5, wherein a substrate heating temperature at which the primary coating and the hydrophilic coating are formed by a vapor deposition method is 250 ℃ or higher.

7. The method of claim 5 or 6, wherein the vapor deposition method is an ion beam assisted vapor deposition method or an electron beam method.

Technical Field

The present invention relates to a lens with a hydrophilic antireflection film and a method for manufacturing the same.

Background

For example, in a monitoring camera or a vehicle-mounted camera, an antifogging coating for preventing fogging of a lens is required. As the antifogging coating layer, for example, a technique of providing a hydrophilic film on the outermost layer is known. However, the conventional hydrophilic film adsorbs not only moisture but also oil components in the air. As a result, hydrophilicity is reduced, and good antifogging property cannot be obtained. Therefore, as shown in the following patent documents, a hydrophilic coating layer using a photocatalytic material has been developed as a hydrophilic film.

In the invention described in patent document 1, an antifogging antireflection film is formed on a transparent substrate. The antifogging antireflection film is formed by alternately laminating a high refractive index film and a low refractive index film. The high refractive index film is a titanium oxide film exhibiting a photocatalytic reaction. The outermost layer of the antifogging antireflection film is a low refractive index film made of an inorganic chemical substance exhibiting hydrophilicity. Thus, the titanium oxide film in patent document 1 is covered with the low refractive index film.

In addition, in the invention described in patent document 2, a multilayer optical film is formed, which is composed of a plurality of thin films on an optical substrate and can suppress the reflectance to be low. An antifogging film containing photocatalyst particles and exhibiting hydrophilicity can be used as the outermost layer of the optical multilayer film.

Disclosure of Invention

(problems to be solved by the invention)

However, in the invention described in patent document 1, it is considered that the outermost low refractive index film is an obstacle, and the titanium oxide film cannot be excited appropriately and cannot function effectively as a photocatalyst.

In the invention described in patent document 2, when the film thickness of the antifogging film is calculated based on the refractive index and the wavelength, it is found that the film thickness is extremely thick. In addition, the antifogging film has a higher refractive index than glass. Accordingly, the antifogging film having a high refractive index and a thick film is located at the outermost layer, and therefore, the antireflection effect is reduced.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a hydrophilic antireflection film-equipped lens having antifogging properties without impairing antireflection effects, and a method for producing the same.

(means for solving the problems)

The lens with a hydrophilic antireflection film of the present invention is characterized by having, on the surface of a glass lens, at least a hydrophilic antireflection film in which a primary film and a hydrophilic film are laminated in this order, the primary film being composed of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅A mixed layer of at least one material selected from the group consisting of (1) a hydrophilic film and (30) a base film, the hydrophilic film being formed on the surface of the base film by TiO₂And Ti₃O₅A single layer of titanium oxide or titanium nitride made of TiN, or a mixed layer containing 50% or more of at least one of the titanium oxide and the titanium nitride,the film thickness is 1nm to 30 nm.

In the present invention, the hydrophilic membrane preferably has a porosity of 20% or less.

In the present invention, the hydrophilic anti-reflection film is laminated on the surface of the glass lens in the order of the anti-reflection film, the base film, and the hydrophilic film, and the anti-reflection film has one or more layers selected from SiO₂、MgF₂、ZrO₂、Al₂O₃、TiO₂、Ti₃O₅、Ta₂O₅And Nb₂O₅Or a mixed layer containing two or more materials.

The method for producing a lens with a hydrophilic antireflection film according to the present invention is characterized by comprising the steps of: forming an under film on a surface of the glass lens, the under film being formed of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅A mixed layer of at least one of the above materials, and having a film thickness of 1nm to 30 nm; forming a hydrophilic film on the surface of the primary coating, the hydrophilic film being formed of TiO₂And Ti₃O₅A single layer of at least one of titanium oxide and titanium nitride made of TiN, or a mixed layer containing at least 50% of at least one of the titanium oxide and the titanium nitride, and has a film thickness of 1nm to 30 nm.

In the present invention, it is preferable that the base film and the hydrophilic film are formed by a vapor deposition method or a sputtering method.

In the present invention, it is preferable that the substrate heating temperature at which the primary film and the hydrophilic film are formed by a vapor deposition method is 250 ℃.

In the present invention, as the vapor deposition method, an ion beam assisted vapor deposition method or an electron beam method is preferably used.

(Effect of the invention)

According to the present invention, a lens with a hydrophilic antireflection film having antifogging properties without impairing antireflection effects and a method for producing the same can be provided.

Drawings

FIG. 1 is a schematic view of a lens with a hydrophilic antireflection film according to this embodiment.

FIG. 2 is a partially enlarged schematic view of a lens with a hydrophilic antireflection film according to the first embodiment.

FIG. 3 is a partially enlarged schematic view of a lens with a hydrophilic antireflection film according to a second embodiment.

Fig. 4 is a graph showing the relationship between the UV irradiation time and the contact angle in example 1, comparative example 1, and comparative example 2.

Fig. 5 is a graph showing the relationship between the UV irradiation time and the contact angle in example 1 and example 5.

Fig. 6 is a graph showing the relationship between the wavelength and the reflectance of example 1, comparative example 3, and reference example (uncoated).

Detailed Description

Hereinafter, an embodiment for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail.

The present inventors have conducted intensive studies on a hydrophilic film using a photocatalytic material as an outermost layer and a base film, and as a result, have obtained a sufficient hydrophilic effect without impairing the antireflection effect and improved antifogging properties. That is, the lens with a hydrophilic antireflection film according to the present embodiment includes the following characteristic portions (1) to (3).

(1) The surface of the glass lens is provided with a hydrophilic antireflection film in which at least a primary film and a hydrophilic film are laminated in this order.

(2) The bottom film is selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅A mixed layer of more than one material of (2). The primary coating has a film thickness of 1nm to 30 nm.

(3) The hydrophilic film is made of TiO by passing through the surface of the primary film₂And Ti₃O₅A single layer of titanium oxide or titanium nitride made of TiN, or a mixed layer containing 50% or more of at least one of titanium oxide and titanium nitride. The hydrophilic film has a film thickness of 1nm to 30 nm.

In addition, in the above (2) and (3), "%" as a content is "% by mass". FIG. 1 is a schematic view of a lens with a hydrophilic antireflection film according to this embodiment. The hydrophilic antireflection film-equipped lens 1 shown in fig. 1 is configured to have: a glass lens 2 as a substrate, and a hydrophilic antireflection film 3 formed on the surface of the glass lens 2 on the light incident side.

The glass lens 2 is not particularly limited, and is, for example, a glass lens for a monitoring camera or a vehicle-mounted camera. The surface of the glass lens 2 on which the hydrophilic antireflection film 3 is formed is, for example, aspherical. The glass lens 2 in fig. 1 is, for example, a meniscus lens having negative refractive power, but may be a meniscus lens having positive refractive power, or may be a biconvex lens, a biconcave lens, or the like. However, the surface of the glass lens 2 may have a shape other than an aspherical surface.

As shown in (1) above, the hydrophilic antireflection film 3 includes at least a primary film and a hydrophilic film. Further, the primary membrane has the characteristic portion of the above (2), and the hydrophilic membrane has the characteristic portion of the above (3). In addition, the hydrophilic antireflection film 3 exhibits an antireflection effect as a whole in terms of optical characteristics.

The hydrophilic antireflection film 3 will be described in more detail below.

< embodiment 1 >

As shown in fig. 2, the hydrophilic antireflection film 3 of the first embodiment is formed by laminating an antireflection film 4, a base film 5, and a hydrophilic film 6 in this order from the surface of the glass lens 2.

The antireflection film 4 has 1 or more layers of SiO selected from the group consisting of₂、MgF₂、ZrO₂、Al₂O₃、TiO₂、Ti₃O₅、Ta₂O₅And Nb₂O₅Or a mixed layer containing two or more materials. These inorganic compounds constituting the antireflection film 4 are all transparent oxides.

The anti-reflection film 4 is adjusted to have a reflectance lower than that of the glass lens 2 alone. Specifically, the refractive index and the film thickness of each layer are determined so that the entire lens provided with the antireflection film 4, the base film 5, and the hydrophilic film 6 has a desired spectral reflectance. Therefore, if the film has a lower refractive index than the glass lens 2, the antireflection film 4 may be a single layer. In the case of a multilayer film, the multilayer film can be configured such that a low refractive index layer and a high refractive index layer are alternately stacked. At this time, the high refractive index layer may have a higher refractive index than the glass lens 2. In the multilayer film, the low refractive index layer is preferably located at the outermost layer of the antireflection film 4. The antireflection film 4 may be formed by laminating one to fifteen layers, and preferably one to ten layers, for example. The number of layers, material, and film thickness of the antireflection film 4 can be variously selected based on the wavelength region in which the reflectance is suppressed.

The thickness of the antireflection film 4 is not limited, and the thickness (total thickness) of the antireflection film 4 is about 50nm to 500 nm.

The primary coating 5 formed on the surface of the antireflection film 4 shown in fig. 2 functions as a base for promoting crystal grain growth of the hydrophilic film 6. The bottom film 5 is made of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅A mixed layer of more than one material of (2).

When the outermost layer (preferably, a low refractive index film) of the antireflection film 4 is formed using a material that can be selected as the primary film 5, the primary film 5 and the outermost layer of the antireflection film 4 may be formed using different materials, or the outermost layer of the antireflection film 4 may be used as the primary film 5.

The thickness of the primary coating 5 is adjusted within a range of 1nm to 30nm from the viewpoint of crystal grain growth and antireflection effect of the hydrophilic film 6. Even when a measurement error or variation occurs depending on the measurement conditions of the thickness of the primary coating 5, for example, the desired contact angle is satisfied while maintaining the transparency, it is possible to estimate an embodiment including the configuration of the present embodiment. The thickness of the primary coating is preferably 5nm to 15 nm.

The hydrophilic film 6 formed on the surface of the primary film 5 is made of TiO₂And Ti₃O₅A single layer of titanium oxide or titanium nitride made of TiN, or a mixed layer containing 50% or more of at least one of titanium oxide and titanium nitride.

As described above, the hydrophilic film 6 may be a mixed layer containing 50% or more and less than 100% of titanium oxide and/or titanium nitride, or may be a single layer of 100% of titanium oxide or titanium nitride. The mixed layer may be formed by mixing a metal oxide other than titanium oxide and titanium nitride, or by mixing at least one of a semiconductor material, a conductive material, and an insulating material other than titanium oxide and titanium nitride. In addition, the material other than titanium oxide and titanium nitride contained in the hydrophilic film 6 needs to be a material capable of maintaining the photocatalytic effect by titanium oxide and titanium nitride while maintaining transparency in the mixed layer with titanium oxide and titanium nitride. For example, SiO can be exemplified as a material other than titanium oxide and titanium nitride₂、Ta₂O₅、Nb₂O₅、ZrO₂、Al₂O₃、MgF₂。

When the hydrophilic film 6 is formed of the mixed layer, it is preferable that 80% or more of titanium oxide and/or titanium nitride is contained.

Ti in titanium oxide₃O₅Can be used as film-forming TiO₂The starting material of (2), and Ti may be added₃O₅All converted to TiO₂The film may be formed (phase-changed) in a state where a part of Ti remains in the film₃O₅. The composition of titanium oxide and titanium nitride can be analyzed by a conventional method, and for example, the composition can be measured by a spectrophotometer. In addition, titanium oxide constituting the hydrophilic film 6 is not limited to TiO₂Single phase, and TiO₂And Ti₃O₅In addition to the mixed phases of (3), may also be composed of Ti₃O₅The single phase composition of (3).

In the present embodiment, the hydrophilic film 6 may be a titanium nitride single layer, but is preferably formed in a film structure including a titanium oxide single layer or at least a titanium oxide, preferably in addition to obtaining a sufficient hydrophilic effect (exciting a photocatalyst).

The thickness of the hydrophilic film 6 is 1nm to 30nm from the viewpoint of transparency and crystal grain growth of the hydrophilic film 6. Thus, the hydrophilic film 6 is formed as a thin film on the surface of the base film 5. The thickness of the hydrophilic film 6 is preferably 5nm to 15 nm.

In the present embodiment, the porosity of the hydrophilic membrane 6 is preferably 20% or less. The porosity of 0%, that is, the state where no pores exist in the hydrophilic membrane 6, is also included in the present embodiment. However, in order to improve the photocatalytic effect, it is preferable to have pores and increase the effective surface area. Therefore, in the present embodiment, it is preferable that the hydrophilic membrane 6 has a porosity of more than 0% and 20% or less. The lower limit of the porosity of the hydrophilic membrane 6 is more preferably 2% or more, and still more preferably 5% or more. Even when measurement errors or variations occur due to the measurement conditions of the porosity, for example, the configuration including the present embodiment can be estimated by satisfying a desired contact angle degree while maintaining transparency.

< second embodiment >

As shown in fig. 3, the hydrophilic antireflection film 3 of the second embodiment is formed by laminating a base film 5 and a hydrophilic film 6 in this order on the surface of a glass lens 2. The second embodiment is a configuration in which the antireflection film 4 shown in the first embodiment is removed.

The film structure of the base film 5 and the hydrophilic film 6 is described with reference to the first embodiment.

In the second embodiment shown in fig. 3, the base film 5 is preferably formed of a material having a refractive index lower than that of the glass lens 2. For example, MgF may be selected as base film 5₂。

Further, an arbitrary pretreatment coating (not shown) may be applied between the surface of the glass lens 2 and the antireflection film 4 in fig. 2, or between the surface of the glass lens 2 and the undercoat film 5 in fig. 3.

However, titanium oxide used as the hydrophilic film 6 of the present embodiment has a high refractive index. Therefore, in the prior art, a titanium oxide film has not been used for the outermost layer of a multilayer film having an antireflection effect formed on the lens surface.

In the present embodiment, the hydrophilic film 6 is formed on the surface of the primary film 5 made of a predetermined material and a thin film. Thus, even if the hydrophilic film 6 has a small film thickness, it is considered that the growth of crystal grains of the photocatalytic material of titanium oxide or titanium nitride can be accelerated. By growing the crystal grains of the hydrophilic film 6 in this manner, a sufficient hydrophilic effect (exciting photocatalyst) can be obtained even if the film thickness is thin.

Further, since the hydrophilic film 6 has a small film thickness, even if the hydrophilic film 6 is provided as the outermost layer, the antireflection effect is not impaired.

As described above, according to the present embodiment, excellent hydrophilicity can be obtained without impairing the antireflection effect. In the present embodiment, excellent hydrophilicity can be maintained for a long time by the photocatalytic action. Therefore, the user can maintain the antireflection effect and the excellent antifogging property for a long time by using the lens with the hydrophilic antireflection film of the present embodiment in a monitoring camera or an in-vehicle camera or the like on the premise of not wiping the lens surface at ordinary times.

< method for producing lens with hydrophilic antireflection film >

A method for manufacturing a lens with a hydrophilic antireflection film according to the first embodiment shown in fig. 2 will be described.

First, the antireflection film 4 is formed on the surface of the glass lens 2. In this embodiment, one or more layers selected from SiO are formed₂、MgF₂、ZrO₂、Al₂O₃、TiO₂、Ti₃O₅、Ta₂O₅And Nb₂O₅The antireflection film 4 is formed of a single layer or a mixed layer containing two or more materials.

After the antireflection film 4 is formed, the primary film 5 is formed on the surface of the antireflection film 4. In this embodiment, the material is selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅And Y₂O₃Or 50% or more of a single layer of a material selected from ZrO₂、MgF₂、Ta₂O₅、Nb₂O₅、Y₂O₃、TiO₂And Ti₃O₅The mixed layer of one or more materials of (2) forms the primary coating 5. The thickness of the primary coating 5 is adjusted within a range of 1nm to 30 nm.

Next, a hydrophilic film 6 is formed on the surface of the primary film 5. By the reaction of TiO₂And Ti₃O₅A single layer of at least one of titanium oxide and titanium nitride made of TiN, or a mixed layer containing at least 50% of at least one of titanium oxide and titanium nitride is formed into the hydrophilic film 6. The thickness of the hydrophilic film 6 is adjusted in a range of 1nm to 30 nm.

In the present embodiment, although the method for forming the antireflection film 4, the primary film 5, and the hydrophilic film 6 is not limited, the antireflection film 4, the primary film 5, and the hydrophilic film 6 are preferably formed by a vapor deposition method or a sputtering method.

As the vapor deposition method, an Ion-Beam assisted vapor deposition (IAD) method or an Electron Beam (Electron Beam: EB) method is preferably used. In the ion beam assisted vapor deposition method, during vacuum vapor deposition, gas ions are irradiated to the surface of a glass lens as a substrate with an ion gun. In addition, in the electron beam method, an evaporation material is put into a crucible under a high vacuum environment, and an electron beam is irradiated to the crucible, thereby heating and evaporating the evaporation material in the crucible.

For example, in the present embodiment, when the hydrophilic film 6 is formed by a vapor deposition method, Ti is used₃O₅As a vapor deposition material, Ti was evaporated by heating under reduced pressure in a film forming chamber₃O₅. Evaporated Ti₃O₅Facing the surface of the glass lens 2 as a substrate. At this time, with O₂Is bonded to Ti₃O₅To TiO₂And is deposited on the surface of the glass lens 2. Therefore, when the hydrophilic film 6 is formed by the vapor deposition method, the hydrophilic film 6 easily forms TiO₂Single phase or TiO₂And Ti₃O₅Mixed phases of (1).

In addition, in the present embodiment, when the hydrophilic film 6 is formed by the vapor deposition method, the substrate heating temperature in the film forming chamber is preferably 250 ℃ or higher. The upper limit of the substrate heating temperature is not limited, but is preferably adjusted to, for example, 400 ℃.

Further, it is preferably 5.0X 10^-3Oxygen gas is introduced under a pressure of Pa or more when the hydrophilic film 6 is formed of titanium oxide. Further, it is more preferably 1.0X 10^-2Pa～3.0×10^-2The pressure of oxygen is adjusted under the condition of Pa.

By adjusting the substrate heating temperature and the oxygen gas pressure in this manner, the growth of crystal grains in the hydrophilic film 6 can be promoted in accordance with the base effect (bottom effect) of the base film 5.

In this embodiment, the base film 5 and the hydrophilic film 6 are preferably formed continuously. Therefore, the primary film 5 and the hydrophilic film 6 are formed by the same film forming method. In this case, the method of forming the primary coating 5, the hydrophilic coating 6, and the antireflection coating 4 may be different. For example, the following examples are given in the experiments described below: the primary coating 5 and the hydrophilic coating 6 are formed by ion beam assisted vapor deposition, and the antireflection coating 4 is formed by electron beam. In addition, there are the following examples: the primary coating 5 and the hydrophilic coating 6 are formed by an electron beam method, and the antireflection coating 4 is formed by an ion beam assisted vapor deposition method.

In the second embodiment shown in fig. 3, only the primary film 5 and the hydrophilic film 6 may be formed.

In the present embodiment, a hydrophilic film 6 containing titanium oxide or titanium nitride is formed on the surface of the primary film 5. The under film 5 in this embodiment has an effect of promoting the growth of crystal grains of the hydrophilic film 6. Therefore, even when the hydrophilic film 6 is formed by a thin film of about 1nm to 30nm (preferably about 5nm to 15 nm), the crystal grain growth of the hydrophilic film 6 can be promoted and a sufficient hydrophilic effect (exciting photocatalyst) can be obtained.

In this embodiment, the hydrophilic film 6 and the primary film 5 are both thin in thickness of about 1nm to 30nm (preferably about 5nm to 15 nm), and the antireflection effect is not impaired.

In addition, in the present embodiment, since both the hydrophilic film 6 and the primary film 5 can be formed with a thin film thickness, the same production efficiency as in the conventional technique can be obtained.

As described above, according to the method for producing the hydrophilic antireflection film-provided lens 1 of the present embodiment, the hydrophilic antireflection film-provided lens 1 having an excellent hydrophilic effect can be produced simply and appropriately without impairing the antireflection effect.