WO2018216540A1 - Lens having hydrophilic anti-reflection film and production method therefor - Google Patents

Abstract

The purpose of the present invention is to provide a lens that has a hydrophilic anti-reflection film and that exhibits anti-fogging properties without compromising the anti-reflection effect, and a production method for the lens. This lens having a hydrophilic anti-reflection film is characterized by having, on a surface of a glass lens, the hydrophilic anti-reflection film obtained by sequentially laminating at least an underlying film and a hydrophilic film, wherein: the underlying film is formed as a single layer or the like selected from ZrO2, MgF2, Ta2O5, Nb2O5, and Y2O3, and has a thickness of 1-30 nm; and the hydrophilic film has a thickness of 1-30 nm and is formed, on a surface of the underlying film, as a single layer of a titanium oxide including at least one of TiO2 and Ti3O5, a single layer of a titanium nitride including TiN, or a mixed layer containing 50% or more of at least one of a titanium oxide and a titanium nitride.

Description

Lens with hydrophilic antireflective film and method for manufacturing the same

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

For example, in surveillance cameras and in-vehicle cameras, there is a demand for an antifogging coat for preventing lens fogging. As the antifogging coat, for example, it is known to provide a hydrophilic film on the outermost layer. However, conventional hydrophilic membranes also adsorb oil components as well as moisture in the air. As a result, the hydrophilicity is reduced, and good antifogging properties can not be obtained. Then, as shown to the following patent documents, the hydrophilic coat which used the photocatalyst material is developed as a hydrophilic membrane.

In the invention described in Patent Document 1, an antifogging antireflective film is formed on a transparent substrate. The antifogging antireflective film has a configuration in which a high refractive index film and a low refractive index film are alternately stacked. The high refractive index film is a titanium oxide film exhibiting photocatalytic reaction. The outermost layer of the antifogging antireflective film is a low refractive index film made of an inorganic chemical exhibiting hydrophilicity. Therefore, the titanium oxide film in Patent Document 1 is covered with a low refractive index film.

Further, in the invention described in Patent Document 2, an optical multilayer film composed of a plurality of thin films and having a low reflectance is formed on an optical substrate. An antifogging thin film containing photocatalyst particles and exhibiting hydrophilicity is used as the outermost layer of the optical multilayer film.

JP, 2016-224113, A Japanese Patent Application Laid-Open No. 11-271505

However, in the invention described in Patent Document 1, it is considered that the low refractive index film of the outermost layer interferes, and the titanium oxide film is not appropriately excited and does not function effectively as a photocatalyst.

In the invention described in Patent Document 2, when the film thickness of the antifogging thin film is calculated based on the refractive index and the wavelength, it is found that the film thickness is very thick. In addition, the antifogging thin film has a refractive index higher than that of glass. Thus, the antireflective effect is reduced by the fact that the antifogging thin film having a high refractive index and a thick film is positioned at the outermost layer.

The present invention was made based on the above-mentioned problem awareness, and an object of the present invention is to provide a lens with a hydrophilic antireflective film having antifogging properties without impairing the antireflective effect, and a method of manufacturing the same.

The lens with a hydrophilic antireflective film of the present invention has a hydrophilic antireflective film in which at least a base film and a hydrophilic film are sequentially laminated on the surface of a glass lens, and the base film is ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , and It is formed of a mixed layer containing 50% or more of one or more materials selected from Ti ₃ O ₅ and has a film thickness of 1 nm or more and 30 nm or less, and the hydrophilic film comprises TiO ₂ and A single layer of titanium oxide made of at least one of Ti ₃ O ₅ 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, and the film thickness is 1 nm that's all It is characterized by being 30 nm or less.

In the present invention, the porosity of the hydrophilic film is preferably 20% or less.

In the present invention, the hydrophilic antireflective film is laminated on the surface of the glass lens in the order of an antireflective film, the underlayer and the hydrophilic film, and the antireflective film is SiO ₂ , MgF ₂ , It has one or more single layers or mixed layers containing two or more materials selected from ZrO ₂ , Al ₂ O ₃ , TiO ₂ , Ti ₃ O ₅ , Ta ₂ O ₅ , and Nb ₂ O ₅ Preferably, it is formed.

The method for producing a lens with a hydrophilic antireflective film according to the present invention comprises a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ and Y ₂ O _{3 on} the surface of a glass lens, or , ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ in a mixed layer containing 50% or more of one or more materials selected from A step of forming a base film having a thickness of 1 nm to 30 nm, and a single layer of titanium oxide made of at least one of TiO ₂ and Ti ₃ O ₅ or titanium nitride made of TiN on the surface of the base film Forming a hydrophilic film having a thickness of 1 nm or more and 30 nm or less in a mixed layer containing 50% or more of at least one of the titanium oxide and the titanium nitride.

In the present invention, it is preferable to form the underlayer film and the hydrophilic film by vapor deposition or sputtering.

In the present invention, the substrate heating temperature at the time of forming the base film and the hydrophilic film by the vapor deposition method is preferably 250 ° C. or more.

In the present invention, it is preferable to use an ion beam assisted deposition method or an electron beam method as the deposition method.

ADVANTAGE OF THE INVENTION According to this invention, the lens with a hydrophilic anti-reflective film provided with anti-fogging property, and its manufacturing method can be provided, without impairing an anti-reflective effect.

It is a schematic diagram of the lens with a hydrophilic anti-reflective film of this embodiment. It is a partial expansion schematic diagram of the lens with a hydrophilic anti-reflective film of 1st Embodiment. It is a partial expansion schematic diagram of the lens with a hydrophilic anti-reflective film of 2nd Embodiment. It is a graph which shows the relationship between UV irradiation time of Example 1, the comparative example 1, and the comparative example 2, and a contact angle. It is a graph which shows the relationship of the UV irradiation time of Example 1 and Example 5, and a contact angle. It is a graph which shows the relationship of the wavelength of Example 1, the comparative example 3, and the reference example (uncoated), and a reflectance.

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

The inventors of the present invention conducted intensive studies on a hydrophilic film and a base film using a photocatalytic material as the outermost layer. As a result, a sufficient hydrophilic effect is obtained without impairing the antireflective effect, and the antifogging property is obtained. It came to improve. That is, the lens with a hydrophilic anti-reflection film of the present embodiment is provided with the following characteristic portions (1) to (3).

(1) The surface of the glass lens has at least a hydrophilic antireflective film laminated in the order of a base film and a hydrophilic film.
(2) The underlayer is a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ It is formed of a mixed layer containing 50% or more of one or more materials selected from O ₅ , Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ . The film thickness of the underlayer is 1 nm or more and 30 nm or less.
(3) The hydrophilic film is a single layer of titanium oxide made of at least one of TiO ₂ and Ti ₃ O ₅ , titanium nitride made of TiN, or at least one of titanium oxide and titanium nitride on the surface of the base film. Is formed of a mixed layer containing at least 50%. The film thickness of the hydrophilic film is 1 nm or more and 30 nm or less.

In addition, in said (2) and (3), "%" which is content is "mass%."

FIG. 1 is a schematic view of a lens with a hydrophilic antireflective film of the present embodiment. The lens 1 with a hydrophilic antireflective film shown in FIG. 1 is configured to have a glass lens 2 as a substrate and a hydrophilic antireflective film 3 formed on the surface of the glass lens 2 on the light incident side. .

Although the glass lens 2 is not particularly limited, it is, for example, a glass lens for a surveillance camera or an on-vehicle camera. The surface of the glass lens 2 on which the hydrophilic antireflective film 3 is formed is, for example, an aspheric surface. The glass lens 2 of FIG. 1 is, for example, a meniscus lens having negative power, but may be a meniscus lens having positive power, or may be a biconvex lens or a biconcave lens. However, the surface of the glass lens 2 may be other than an aspheric surface.

The hydrophilic antireflective film 3 includes at least a base film and a hydrophilic film, as described in (1) above. In addition, the undercoat film is provided with the characteristic portion of (2), and the hydrophilic film is provided with the characteristic portion of (3). Optically, the whole of the hydrophilic antireflective film 3 exerts an antireflective effect.

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

First Embodiment
As shown in FIG. 2, the hydrophilic antireflection film 3 of the first embodiment is laminated in the order of the antireflection film 4, the base film 5, and the hydrophilic film 6 from the surface of the glass lens 2.

The antireflective film 4 is selected from SiO ₂ , MgF ₂ , ZrO ₂ , Al ₂ O ₃ , TiO ₂ , Ti ₃ O ₅ , Ta ₂ O ₅ , and Nb ₂ O _{5 on} the surface of the glass lens 2. It is configured to have one or more single layers or a mixed layer containing two or more kinds of materials. All of these inorganic compounds constituting the antireflective film 4 are transparent oxides.

The antireflection film 4 is adjusted to have a lower reflectance than in the case 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 antireflective film 4, the base film 5, and the hydrophilic film 6 has a desired spectral reflectance. Therefore, as long as the film is lower than the refractive index of the glass lens 2, the antireflection film 4 may have one layer. Moreover, in the case of a multilayer film, it can be set as the structure which laminated | stacked the low-refractive-index layer and the high refractive index layer alternately. At this time, the high refractive index layer may be higher than the refractive index of the glass lens 2. In the multilayer film, the low refractive index layer is preferably located at the outermost layer of the antireflective film 4. The antireflective film 4 is, for example, laminated by about 1 to about 15 layers, and preferably laminated by 1 to 10 layers. The number of laminated layers, the material, and the film thickness of the antireflective film 4 can be variously selected based on the wavelength region in which the reflectance is suppressed.

Although the film thickness of the antireflective film 4 is not limited, the film thickness (total thickness) of the antireflective film 4 is about 50 nm to 500 nm.

Underlayer 5 formed on the surface of antireflection film 4 shown in FIG. 2 functions as an underlayer that promotes crystal grain growth of hydrophilic film 6. The underlayer 5 is a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ in a mixed layer containing 50% or more of one or more materials.

When the outermost layer (preferably a low refractive index film) of the antireflective film 4 is formed by using a material selectable as the underlayer 5, the material of which the underlayer 5 and the outermost layer of the antireflective film 4 are different The outermost layer of the antireflective film 4 can also be used as the base film 5.

The film thickness of the base film 5 is adjusted in the range of 1 nm or more and 30 nm or less from the viewpoint of crystal grain growth and antireflection effect of the hydrophilic film 6. In addition, even if measurement errors or deviations occur due to measurement conditions of the film thickness of the base film 5, etc., for example, it is presumed that the configuration of the present embodiment is included by satisfying the desired contact angle while maintaining the transparency. It is possible. The film thickness of the base film 5 is preferably 5 nm or more and 15 nm or less.

The hydrophilic film 6 formed on the surface of the base film 5 is a single layer of titanium oxide made of at least one of TiO ₂ and Ti ₃ O ₅ or titanium nitride made of TiN, or at least at least titanium oxide and titanium nitride. It is formed of a mixed layer containing 50% or more of one.

Thus, even if the hydrophilic film 6 is a mixed layer containing titanium oxide and / or titanium nitride at 50% or more and less than 100%, the hydrophilic film 6 is a single layer of titanium oxide or titanium nitride at 100%. It is also good. As the mixed layer, titanium oxide and metal oxides other than titanium nitride can be mixed, or in addition to titanium oxide and titanium nitride, at least one of a semiconductor substance, a conductive substance, and an insulating substance can be mixed. . The material other than titanium oxide and titanium nitride contained in the hydrophilic film 6 is a material capable of maintaining the photocatalytic effect of titanium oxide and titanium nitride while maintaining transparency in the mixed layer of titanium oxide and titanium nitride. It is necessary to be there. For example, it can be exemplified _{SiO 2, Ta 2 O 5,} Nb 2 O 5, ZrO 2, Al 2 O 3, MgF 2 as a material other than titanium oxide and titanium nitride.

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

Among titanium oxides, Ti ₃ O ₅ can be used as a starting material for depositing TiO _2, and all Ti ₃ O ₅ may be deposited in a state of being replaced with TiO ₂ (phase Transition), a part of Ti ₃ O ₅ may be left in the film. The compositional analysis of titanium oxide and titanium nitride can use an existing method, and for example, can be measured by a spectrophotometer. Incidentally, the titanium oxide constituting the hydrophilic layer 6, TiO ₂ single phase, and, in addition to the mixed phase of TiO ₂ and _Ti 3 _{O 5,} may be constituted by a single phase of _Ti 3 _{O 5.}

In the present embodiment, the hydrophilic film 6 may be a titanium nitride single layer, but it is sufficient to have a titanium oxide single layer or a film structure including at least titanium oxide (photocatalytic excitation). It is preferable to obtain

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

Further, in the present embodiment, the porosity of the hydrophilic film 6 is preferably 20% or less. Even if the porosity is 0%, that is, the hydrophilic film 6 has no pores, it is included in the present embodiment. However, in order to enhance the photocatalytic effect, it is preferable to have pores and increase the effective surface area. Therefore, in the present embodiment, the hydrophilic film 6 preferably has a porosity of more than 0% and 20% or less. The lower limit value of the porosity of the hydrophilic film 6 is more preferably 2% or more, and still more preferably 5% or more. Even when a measurement error or deviation occurs due to a measurement condition of porosity, etc., it is assumed that the configuration of the present embodiment is included by satisfying a desired contact angle while maintaining transparency, for example. It is possible.

Second Embodiment
As shown in FIG. 3, the hydrophilic antireflection film 3 of the second embodiment is laminated on the surface of the glass lens 2 in the order of the base film 5 and the hydrophilic film 6. The second embodiment has a configuration in which the antireflective film 4 shown in the first embodiment is removed.

For the film configuration of the undercoat film 5 and the hydrophilic film 6, refer to the description of the first embodiment above.

In the second embodiment shown in FIG. 3, the underlayer 5 is preferably formed of a material having a refractive index lower than that of the glass lens 2. For example, MgF ₂ can be selected as the underlayer 5.

An optional pretreatment coat (not shown) is provided between the surface of the glass lens 2 and the anti-reflection film 4 in FIG. 2 or between the surface of the glass lens 2 and the base film 5 in FIG. May be applied.

By the way, titanium oxide used as the hydrophilic film 6 of the present embodiment has a high refractive index. For this reason, conventionally, a titanium oxide film has not been used as the outermost layer of a multilayer film having an antireflection effect, which is formed on the lens surface.

In the present embodiment, the hydrophilic film 6 is formed on the surface of the base film 5 made of a predetermined material and a thin film. Thereby, it is considered that even if the film thickness of the hydrophilic film 6 is thin, crystal grains of titanium oxide or titanium nitride photocatalytic material can be grown large. As described above, by growing the crystal grains of the hydrophilic film 6, the hydrophilic effect (photocatalyst excitation) can be sufficiently obtained even if the film thickness is thin.

Further, since the film thickness of the hydrophilic film 6 is thin, even when the hydrophilic film 6 is provided as the outermost layer, the antireflection effect is not impaired.

As described above, according to the present embodiment, it is possible to obtain excellent hydrophilicity without impairing the antireflection effect. In the present embodiment, excellent hydrophilicity can be maintained for a long time by the photocatalytic action. Therefore, when the user uses the lens with a hydrophilic anti-reflection film of the present embodiment for a surveillance camera, an on-vehicle camera, etc., which usually does not presuppose that the lens surface is wiped, the anti-fogging effect is excellent It is possible to hold for a long time.

<Method of manufacturing lens with hydrophilic antireflective film>
A method of manufacturing the lens with a hydrophilic anti-reflection film of the first embodiment shown in FIG. 2 will be described.

First, the antireflective film 4 is formed on the surface of the glass lens 2. In this embodiment, a single layer or two or more materials selected from SiO ₂ , MgF ₂ , ZrO ₂ , Al ₂ O ₃ , TiO ₂ , Ti ₃ O ₅ , Ta ₂ O ₅ , and Nb ₂ O ₅ The antireflective film 4 is formed by depositing one or more mixed layers containing

After forming the antireflective film 4, the base film 5 is formed on the surface of the antireflective film 4. In this embodiment, the underlayer 5 is a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or ZrO ₂ , MgF ₂ , Ta ₂ O _5. And Nb ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ in a mixed layer containing 50% or more of one or more materials. In addition, the film thickness of the underlayer 5 is adjusted in the range of 1 nm to 30 nm.

Subsequently, the hydrophilic film 6 is formed on the surface of the base film 5. The hydrophilic film 6 is a single layer of titanium oxide made of at least one of TiO ₂ and Ti ₃ O ₅ or titanium nitride made of TiN, or a mixed layer containing 50% or more of at least one of titanium oxide and titanium nitride. Form a film. In addition, the film thickness of the hydrophilic film is adjusted in the range of 1 nm to 30 nm.

In the present embodiment, the film formation method of the antireflective film 4, the base film 5 and the hydrophilic film 6 is not limited, but the antireflective film 4, the base film 5 and the hydrophilic film 6 may be formed by vapor deposition or sputtering. It is preferable to form a film by

As the vapor deposition method, it is preferable to use an ion beam assisted deposition (IAD) method or an electron beam (EB) method. In the ion beam assisted deposition method, gas ions are irradiated to the surface of a glass lens as a substrate by an ion gun during vacuum deposition. In the electron beam method, the evaporation material is placed in a crucible in a high vacuum atmosphere, and the crucible is irradiated with an electron beam to heat and evaporate the evaporation material in the crucible.

For example, in the present embodiment, when forming the hydrophilic film 6 by vapor deposition, Ti ₃ O ₅ is heated and evaporated under reduced pressure in a film formation chamber using Ti ₃ O ₅ as a vapor deposition material. The evaporated Ti ₃ O ₅ is directed to the surface of the glass lens 2 as a substrate. At this time, it combines with O ₂ and Ti ₃ O ₅ becomes TiO ₂ and deposits on the surface of the glass lens 2. Therefore, when the hydrophilic film 6 is formed by vapor deposition, the hydrophilic film 6 is likely to be a TiO ₂ single phase or a mixed phase of TiO ₂ and Ti ₃ O ₅ .

Further, in the present embodiment, when the hydrophilic film 6 is formed by vapor deposition, the substrate heating temperature in the film forming chamber is preferably 250 ° C. or higher. Further, although the upper limit value of the substrate heating temperature is not limited, for example, it is preferable to adjust it to 400 ° C. or less.

In addition, it is preferable to introduce oxygen gas at the time of forming the hydrophilic film 6 with titanium oxide at a gas pressure of 5.0 × 10 ⁻³ Pa or more. Further, it is more preferable to adjust the gas pressure of oxygen gas at about 1.0 × 10 ⁻² Pa to 3.0 × 10 ⁻² Pa.

As described above, by adjusting the substrate heating temperature and the gas pressure of the oxygen gas, it is possible to promote crystal grain growth of the hydrophilic film 6 together with the underlying effect of the underlying film 5.

In the present embodiment, it is preferable to form the base film 5 and the hydrophilic film 6 continuously. Therefore, the base film 5 and the hydrophilic film 6 are formed by the same film forming method. At this time, the film forming method may be different between the base film 5 and the hydrophilic film 6 and the antireflective film 4. For example, in the experiment described later, there is an example in which the base film 5 and the hydrophilic film 6 are formed by ion beam assisted deposition, and the antireflective film 4 is formed by electron beam method. Further, there is an embodiment in which the base film 5 and the hydrophilic film 6 are formed by the electron beam method, and the antireflective film 4 is formed by the ion beam assisted deposition method.

Further, in the second embodiment shown in FIG. 3, only the film formation of the base film 5 and the hydrophilic film 6 may be performed.

In the present embodiment, the hydrophilic film 6 having titanium oxide or titanium nitride is formed on the surface of the base film 5. The undercoat film 5 in the present embodiment has an effect of promoting the crystal grain growth of the hydrophilic film 6. For this reason, even when the hydrophilic film 6 is formed as a thin film of about 1 nm to 30 nm (preferably, about 5 nm to 15 nm), crystal grain growth of the hydrophilic film 6 is promoted, and the hydrophilic effect (photocatalytic excitation) is obtained. You can get enough.

Further, in the present embodiment, both of the hydrophilic film 6 and the base film 5 have a thin film thickness of about 1 nm to 30 nm (preferably, about 5 nm to 15 nm), and the antireflection effect is not impaired.

Further, in the present embodiment, since both of the hydrophilic film 6 and the base film 5 can be formed with a thin film thickness, the same manufacturing efficiency as that of the conventional one can be obtained.

As described above, according to the method of manufacturing the lens 1 with a hydrophilic antireflective film of the present embodiment, the lens 1 with a hydrophilic antireflective film having an excellent hydrophilic property without losing the antireflective effect is simple and easy. It can be manufactured appropriately.

Hereinafter, the present embodiment will be more specifically described using examples and comparative examples. In the experiments, Examples 1 to 5 and Comparative Examples 1 to 3 shown below were manufactured.

Example 1
In Example 1, using the materials shown in Table 1 below, an antireflection film, a base film, and a hydrophilic film having the film thickness and refractive index shown in Table 1 were formed at the substrate heating temperature shown in Table 1 , The lens with a hydrophilic anti-reflective film was obtained. In the experiment, the film was formed using a deposition machine (SGC-22SA) manufactured by Showa Vacuum Co., Ltd. The refractive index nd (refractive index at d-line (588 nm)) of the glass lens was 1.85135. The refractive index nd of the glass lens is the same in Examples 2 to 5 and Comparative Examples 1 to 3. Here, the refractive index of each layer was calculated from the reflectance of the film (corresponding to the refractive index of the film in the atmosphere). Specifically, the reflectance of the substrate taken out to the atmosphere was measured by a microscope type spectrophotometer (USPM-RU3) manufactured by Olympus Corporation, and the reflectance was determined in terms of refractive index. The refractive index is at a wavelength of 550 nm. The film thickness can be measured, for example, using a cross-sectional TEM photograph. The above-described measurement of the refractive index and the film thickness is the same as in Examples 2 to 5 and Comparative Examples 1 to 3.

In Example 1, the substrate heating temperature was 350 ° C., and SiO ₂ and Ta ₂ O ₅ were alternately stacked up to seven layers by ion beam assisted deposition to obtain an antireflective film. Next, a base film made of ZrO ₂ and a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) were continuously formed by an electron beam method at a substrate heating temperature of 350 ° C.

The hydrophilic film is deposited using Ti ₃ O ₅ as a starting material, and at this time, all or part of Ti ₃ O ₅ is easily replaced with TiO ₂ to form a film. The membrane structure of the hydrophilic membrane can be measured by a spectrophotometer. In the present embodiment, the hydrophilic film may have a film structure of TiO ₂ single phase, Ti ₃ O ₅ single phase, or mixed phase of TiO ₂ and Ti ₃ O ₅ .

In Example 1, the porosity of the hydrophilic film was 5%. The porosity can be calculated as follows.

First, let n be the known refractive index of the material used for the hydrophilic film, and let n (V) be the refractive index in vacuum of the hydrophilic film formed in this experiment. The refractive index in vacuum was determined by measuring the reflectance during film formation using an optical film thickness meter in a film formation chamber held in vacuum, and converting it to a refractive index. The packing ratio of the hydrophilic membrane can be expressed as follows.

Packing ratio (%) = [refractive index in vacuum (%) / known refractive index (%)] × 100 (%)
Therefore, the porosity is
Porosity (%) = 100 (%)-filling rate (%)
It becomes.

Example 2
In Example 2, using the materials shown in Table 2 below, an antireflection film, a base film, and a hydrophilic film having the film thickness and refractive index shown in Table 2 are formed at the substrate heating temperature shown in Table 2 , The lens with a hydrophilic anti-reflective film was obtained.

In Example 2, the substrate heating temperature is 250 ° C., and SiO ₂ , MgF _2, or Al ₂ O ₃ / Al ₂ O ₃ / ZrO ₂ / SiO ₂ or MgF ₂ are laminated in order from the bottom by electron beam method. The antireflective film was deposited. Next, with the substrate heating temperature kept at 250 ° C., a base film made of ZrO ₂ and a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) were continuously formed by ion beam assisted deposition.

[Example 3]
In Example 3, using the materials shown in Table 3 below, an antireflection film, a base film and a hydrophilic film having the film thickness and refractive index shown in Table 3 are formed at the substrate heating temperature shown in Table 3 , The lens with a hydrophilic anti-reflective film was obtained.

In Example 3, the substrate heating temperature was 25 ° C. (no heating), and the anti-reflection film was alternately stacked up to nine layers of SiO ₂ and Nb ₂ O ₅ by sputtering. Next, a base film consisting of Y ₂ O ₃ and a hydrophilic film consisting of TiO ₂ (Ti ₃ O ₅ ) are continuously formed by sputtering while keeping the substrate heating temperature at 25 ° C. (without heating). did.

Example 4
In Example 4, using the materials shown in Table 4 below, an antireflection film, a base film, and a hydrophilic film having the film thickness and refractive index shown in Table 4 are formed at the substrate heating temperature shown in Table 4 , The lens with a hydrophilic anti-reflective film was obtained.

In Example 4, the substrate heating temperature was 350 ° C., and the antireflection film was formed of a single layer of SiO ₂ by an electron beam method. Continuously, the base film consisting of MgF ₂ and the hydrophilic film consisting of TiO ₂ (Ti ₃ O ₅ ) were formed by electron beam method while keeping the substrate heating temperature at 350 ° C.

[Example 5]
In Example 5, using the materials shown in Table 5 below, an antireflection film, a base film, and a hydrophilic film having the film thickness and refractive index shown in Table 5 are formed at the substrate heating temperature shown in Table 5 , The lens with a hydrophilic anti-reflective film was obtained.

In Example 5, the substrate heating temperature was 350 ° C., and SiO ₂ and Ta ₂ O ₅ were alternately stacked up to seven layers by ion beam assisted deposition to obtain an antireflective film. Next, a base film made of ZrO ₂ and a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) were continuously formed by an electron beam method at a substrate heating temperature of 350 ° C.

In Example 5, the porosity of the hydrophilic membrane was 0%.

Comparative Example 1
In Comparative Example 1, an antireflective film having the film thickness and refractive index shown in Table 6 and a hydrophilic film are formed at the substrate heating temperature shown in Table 6 using the materials shown in Table 6 below, and hydrophilic A lens with an antireflective coating is obtained.

In Comparative Example 1, the substrate heating temperature was 350 ° C., and SiO ₂ and Ta ₂ O ₅ were alternately stacked up to seven layers by ion beam assisted deposition to obtain an antireflective film. Next, a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) was formed by an electron beam method.

In Comparative Example 1, unlike in each of the above-described Examples, the base film for the hydrophilic film was not formed.

Comparative Example 2
In Comparative Example 2, using the materials shown in Table 7 below, an antireflection film, a base film, and a hydrophilic film having the film thickness and refractive index shown in Table 7 are formed at the substrate heating temperature shown in Table 7 , The lens with a hydrophilic anti-reflective film was obtained.

In Comparative Example 2, the substrate heating temperature was 350 ° C., and the anti-reflection film was alternately stacked up to seven layers of SiO ₂ and Ta ₂ O ₅ by ion beam assisted deposition. Next, a base film made of Al ₂ O ₃ and a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) were continuously formed by an electron beam method at a substrate heating temperature of 350 ° C.

In Comparative Example 2, Al ₂ O ₃ was used not used in this embodiment in the base film.

Comparative Example 3
In Comparative Example 3, using the materials shown in Table 8 below, an antireflection film and a hydrophilic film having the film thickness and the refractive index shown in Table 8 are formed at the substrate heating temperature shown in Table 8 A lens with an antireflective film was obtained.

In Comparative Example 3, the substrate heating temperature was 350 ° C., and the anti-reflection film was alternately laminated up to seven layers of SiO ₂ and Ta ₂ O ₅ by ion beam assisted deposition. Next, a hydrophilic film made of TiO ₂ (Ti ₃ O ₅ ) was formed by an electron beam method while keeping the substrate heating temperature at 350 ° C.

In Comparative Example 3, unlike in the above-described Examples, the underlayer film was not formed. In addition, the film thickness of the hydrophilic film is 50 nm, which is thicker than each example.

[Measurement of contact angle]
In the experiment, the lens surface was irradiated with UV, and the relationship between the UV irradiation time and the contact angle was measured. In the measurement of the contact angle, 0.8 μl of pure water was poured on the sample surface, and the contact angle θ was determined. In the experiment, each rubbing test was performed three times each to determine the average value of the contact angles θ. The contact angles shown in FIGS. 4 and 5 are all average values. Also, the UV wavelength in the experiment was about 365 nm. The UV wavelength may be about 280 to 400 nm.

[Test Results of Contact Angles of Example 1 and Comparative Examples 1 and 2]
As shown in FIG. 4, in Example 1, it was found that the contact angle is sharply reduced in a short time by performing the UV irradiation. On the other hand, in Comparative Example 1 in which there is no undercoat film and in Comparative Example 2 in which the material of the undercoat film is different from this example, the contact angle was substantially constant even after UV irradiation.

Thereby, in the Example, as a result of the photocatalytic effect acting by UV irradiation and sufficient hydrophilic property being obtained, it turned out that a contact angle became small.

From these experimental results, it was found that a base film is required for the hydrophilic film, and at this time, it is important to select an appropriate material for the base film. The undercoat film made of a predetermined material is considered to promote crystal grain growth of the hydrophilic film. As a result, even if the film thickness of the hydrophilic film is thin, it is considered that a sufficient hydrophilic effect (photocatalyst excitation) can be obtained.

In this example, a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , is used as the underlayer. A mixed layer containing 50% or more of one or more materials selected from Nb ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ was used as the underlayer.

Since the film thickness of the underlayer is about 5 nm to 30 nm in the example, the film thickness of the underlayer was set to 1 nm or more and 30 nm or less.

In addition, the film thickness of the hydrophilic film was set to 1 nm or more and 30 nm or less based on each example. Since the hydrophilic film has a refractive index higher than that of glass, when the hydrophilic film is formed too thick, the antireflective effect is reduced.

Therefore, in the present embodiment, the hydrophilic film is overlaid on the underlying film made of an appropriate material, and the hydrophilic film is excellently hydrophilic without reducing the thickness of the hydrophilic film and impairing the anti-reflection effect. I was able to get it.

[Test Results of Contact Angle between Example 1 and Example 5]
As shown in FIG. 5, in both Example 1 and Example 5, the contact angle was reduced by UV irradiation. Thereby, not only Example 1 but Example 5 had a photocatalytic effect, and it was possible to obtain hydrophilicity.

However, as shown in FIG. 5, in the fifth embodiment, the decrease in the contact angle with respect to the time lapse of the UV irradiation is slower than in the first embodiment. This is considered to be due to the fact that the pores of the hydrophilic film in Example 5 are smaller than those in Example 1.

Therefore, it was found that it is preferable that the hydrophilic film be provided with pores to some extent. However, since it is considered that even if the porosity is too large, a sufficient photocatalytic effect can not be obtained, the porosity is set to 20% or less.

[Relationship between wavelength and reflectance]
In the experiment, the relationship between the wavelength and the reflectance was investigated using Example 1 and Comparative Example 3 and a reference example (uncoated) in which the antireflective film is not formed. The reflectance was measured by the microscope type spectrophotometer (USPM-RU3) manufactured by Olympus Co., Ltd. described above.

As shown in FIG. 6, the reflectances of Example 1 and Comparative Example 3 were relatively evaluated with reference to the reflectance of the reference example.

As shown in FIG. 6, in Comparative Example 3 in which the film thickness of the hydrophilic film is thick, the reflectance was higher in the visible light range than in the reference example.

On the other hand, in Example 1, the reflectance was lower in the visible light range than in the reference example. Thus, in Example 1, it turned out that the antireflection effect is not impaired.

The lens with a hydrophilic antireflective film of the present invention is excellent in the antireflective effect and the photocatalytic effect. Therefore, the lens surface has excellent hydrophilicity and can improve antifogging properties. In the present invention, a lens with a hydrophilic anti-reflection film is preferably applied to a glass lens for a surveillance camera, an on-vehicle camera, etc., which is not premised that the user usually wipes unlike the side mirror or window glass of a vehicle. be able to.

The present application is based on Japanese Patent Application No. 2017-101663 filed May 23, 2017. All this content is included here.

Claims (7)

1. The surface of the glass lens has at least a hydrophilic antireflective film laminated in the order of a base film and a hydrophilic film,
   The underlayer is a single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O ₃ , or ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ And Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ in a mixed layer containing 50% or more of one or more materials, and the film thickness is 1 nm or more and 30 nm or less,
   The hydrophilic film is a single layer of titanium oxide made of at least one of TiO ₂ and Ti ₃ O ₅ or titanium nitride made of TiN on the surface of the base film, or at least at least the titanium oxide and the titanium nitride. A lens with a hydrophilic antireflective film, characterized in that it is formed of a mixed layer containing 50% or more of one, and the film thickness is 1 nm or more and 30 nm or less.
2. 2. The lens with a hydrophilic anti-reflection film according to claim 1, wherein the porosity of the hydrophilic film is 20% or less.
3. The hydrophilic antireflective film is laminated on the surface of the glass lens in the order of an antireflective film, the base film, and the hydrophilic film,
   The antireflective film is a single layer or two or more selected from SiO ₂ , MgF ₂ , ZrO ₂ , Al ₂ O ₃ , TiO ₂ , Ti ₃ O ₅ , Ta ₂ O ₅ , and Nb ₂ O ₅ The lens with a hydrophilic anti-reflection film according to claim 1 or 2, which is formed to have one or more mixed layers containing a material.
4. A single layer selected from ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and Y ₂ O _{3 on} the surface of a glass lens, or ZrO ₂ , MgF ₂ , Ta ₂ O ₅ , Nb ₂ O ₅₎ forming an underlayer having a thickness of 1 nm to 30 nm in a mixed layer containing 50% or more of one or more materials selected from Y ₂ O ₃ , TiO ₂ , and Ti ₃ O ₅ ;
   A single layer of titanium oxide comprising at least one of TiO ₂ and Ti ₃ O ₅ or titanium nitride comprising TiN, or at least 50% of at least one of the titanium oxide and the titanium nitride is provided on the surface of the underlayer. Forming a hydrophilic film having a thickness of 1 nm or more and 30 nm or less in the mixed layer;
   A method of producing a lens with a hydrophilic antireflective film, comprising:
5. The method for producing a lens with a hydrophilic antireflective film according to claim 4, wherein the underlayer film and the hydrophilic film are formed by vapor deposition or sputtering.
6. The method for producing a lens with a hydrophilic antireflective film according to claim 5, wherein the substrate heating temperature at the time of forming the underlayer film and the hydrophilic film by evaporation method is 250 ° C or more.
7. 7. The method according to claim 5, wherein an ion beam assisted deposition method or an electron beam method is used as the deposition method.

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