WO2018110017A1

WO2018110017A1 - Optical product

Info

Publication number: WO2018110017A1
Application number: PCT/JP2017/033841
Authority: WO
Inventors: 松坂慶二; 能勢正章; 中村勝也; 青木洋輔; 今関秀和; 水町靖; 野村康之; 濱敬二
Original assignee: コニカミノルタ株式会社
Priority date: 2016-12-14
Filing date: 2017-09-20
Publication date: 2018-06-21
Also published as: JP2020024237A

Abstract

An optical product is provided which can achieve desired spectral characteristics while exhibiting a catalytic effect. This optical product has a glass substrate on which a multilayer film of three or more layers is formed, and by using a combination of at least one low refractive index layer and at least one high refractive index layer, the multilayer substrate can adjust the spectral characteristics of the optical product. The top layer furthest from the glass substrate is a low refractive index layer, and a high refractive index layer adjacent to the top layer is a functional layer having a metal oxide with a photocatalytic function as the main component, and satisfies the conditional expressions below. 60nm ≤ TL ≤ 350nm (1) 220nm ≤ Tcat ≤ 700nm (2) Here, TL is the film thickness of the top layer, and Tcat is the film thickness of the functional layer.

Description

Optical products

The present invention relates to an optical product having a multilayer film formed thereon.

For example, titanium oxide is known to have a high photocatalytic effect. More specifically, when the titanium oxide is irradiated with UV light, the oxidation-reduction reaction is strongly promoted, and the surface of the titanium oxide exhibits hydrophilicity that is easily wetted with water. Therefore, the titanium oxide is washed with water droplets such as rain. It is known to have a so-called self-cleaning action.

For example, in Patent Document 1, a low-refractive index layer and a high-refractive index layer are alternately stacked, and a multilayer antireflection film in which the uppermost layer is a low-refractive index layer is provided, and at least a high-refractive index layer immediately below the uppermost layer is provided. An article is disclosed that is a layer of metal oxide such as titanium oxide having photocatalytic activity or a composite film containing titanium oxide. Such articles can be used, for example, as lenses for glasses, cameras, binoculars, microscopes, and the like, and are said to exhibit functions such as antifouling and antifogging. There is a demand for applying such technology to optical products such as in-vehicle cameras and glass building materials that are easily contaminated and difficult for users to clean.

Incidentally, in the technique of Patent Document 1, the thickness of the TiO ₂ that exhibits a photocatalytic function has become a 200nm or less, it may not be able to achieve sufficient photocatalytic effect on optical products placed dirt easily environment is there. On the other hand, if the film thickness of TiO ₂ is increased, the photocatalytic function can be exhibited to some extent, but there is also a problem that desired optical characteristics cannot be obtained.

JP 2000-329904 A

An object of the present invention is to provide an optical product capable of obtaining a desired spectral characteristic while exhibiting a photocatalytic effect.

In order to achieve at least one of the above-described objects, an optical product reflecting one aspect of the present invention is an optical product having a glass substrate on which a multilayer film of three or more layers is formed. By using a combination of one low refractive index layer and at least one high refractive index layer, the spectral characteristics of the optical product are adjusted, and the uppermost layer farthest from the glass substrate has a low refractive index. The high refractive index layer adjacent to the uppermost layer is a functional layer mainly composed of a metal oxide having a photocatalytic function, and satisfies the following conditional expression.
60 nm ≦ TL ≦ 350 nm (1)
220 nm ≦ Tcat ≦ 700 nm (2)
here,
TL: film thickness of the uppermost layer Tcat: film thickness of the functional layer

1A and 1B are diagrams schematically showing a cross section of an optical product according to the present embodiment. It is a figure which shows the spectral characteristics of the multilayer film of the test number 1-1 which is an Example. It is a figure which shows the spectral characteristic of the multilayer film of the test number 1-2 which is an Example. It is a figure which shows the spectral characteristic of the multilayer film of the test numbers 1-3 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test numbers 1-4 which are comparative examples. It is a figure which shows the spectral characteristics of the multilayer film of the test numbers 1-5 which are comparative examples. It is a figure which shows the spectral characteristic of the multilayer film of the test number 2-1 which is an Example It is a figure which shows the spectral characteristics of the multilayer film of the test number 2-2 which is an Example. It is a figure which shows the spectral characteristic of the multilayer film of the test number 2-3 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 2-4 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 3-1 which is an Example It is a figure which shows the spectral characteristics of the multilayer film of the test number 3-2 which is an Example. It is a figure which shows the spectral characteristic of the multilayer film of the test number 3-3 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 3-4 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 4-1 which is an Example It is a figure which shows the spectral characteristics of the multilayer film of the test number 4-2 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 4-3 which is an Example. It is a figure which shows the spectral characteristics of the multilayer film of the test number 4-4 which is an Example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a cross section of an optical product according to the present embodiment. An optical product 100 shown in FIG. 1A has a multilayer film MC having a structure in which low refractive index layers L and high refractive index layers H are alternately laminated on a glass substrate (glass substrate) GL. However, the high refractive index layer H may be in contact with the glass substrate GL. Such an optical product 100 has a light transmission function and a reflection function, and can be used as, for example, an in-vehicle lens, a communication lens, or a building material. In FIG. 1, the layer located between the glass substrate GL and the functional layer 20 may be replaced with an equivalent film of an intermediate refractive index layer instead of a high refractive index layer or a low refractive index layer.

On the other hand, the optical product 100 shown in FIG. 1B has a multilayer structure in which a metal film M is formed on a glass substrate GL, and a high refractive index layer H and a low refractive index layer L are alternately stacked thereon. It has a film MC. However, the high refractive index layer H may be in contact with the metal film M. Such an optical product 100 has a light reflecting function, and can be used as, for example, a reflecting mirror, a building material, or an in-vehicle mirror.

1A and 1B, the uppermost layer 10 farthest from the glass substrate GL is a low refractive index layer L, and the high refractive index layer H adjacent to the uppermost layer 10 is a functional layer 20 of a metal oxide having a photocatalytic function. . By using the low refractive index layer L having a relatively high strength as the uppermost layer 10, scratch resistance can be improved. Moreover, since the functional layer 20 exhibits a photocatalytic function using active oxygen excited by UV light through or through the uppermost layer 10, the functional layer 20 is preferably placed as close as possible to the uppermost layer 10. By providing the functional layer 20 adjacent to the uppermost layer 10, for example, a photocatalytic function can be effectively exhibited. Further, it is desirable that the functional layer 20 has a thickness of 100 nm or more adjacent to the uppermost layer 10. Furthermore, it is preferable to use a metal oxide having a photocatalytic effect and a photoactive effect as the functional layer 20 because the surface organic substances can be removed and the hydrophilicity of the uppermost layer 10 can be maintained. The functional layer 20 using TiO ₂ is preferably formed using IAD (Ion Assisted Deposition (hereinafter referred to as IAD)) because the photocatalytic effect is enhanced.

“Photocatalytic function” refers to the strong oxidizing power generated by the incidence of sunlight or artificial light, which effectively removes toxic substances such as organic compounds and bacteria that come in contact, It refers to a self-cleaning function such as preventing the oil from staying on the surface and washing with water or the like without fixing oily stains, such as titanium dioxide. Note that “adjacent to the uppermost layer” means that the function is not hindered between the uppermost layer 10 and the functional layer 20 in addition to the case where the uppermost layer 10 and the functional layer 20 are in close contact with each other. This includes the case where a layer (for example, a layer of 20 nm or less) is provided.

Furthermore, the optical product 100 of the present embodiment satisfies the following conditional expression.
60 nm ≦ TL ≦ 350 nm (1)
220 nm ≦ Tcat ≦ 700 nm (2)
here,
TL: film thickness of uppermost layer 10 Tcat: film thickness of high refractive index layer H or functional layer 20 adjacent to uppermost layer 10

When the value of the formula (1) is not more than the upper limit, the photocatalytic effect can be exhibited by exchanging active oxygen excited by UV light through the uppermost layer 10. On the other hand, when the value of the formula (1) is equal to or higher than the lower limit, a strong uppermost film can be formed, so that sufficient scratch resistance can be secured. In addition, Preferably, it is satisfy | filling the following formula | equation.
60 nm ≦ TL ≦ 250 nm (1 ′)

Since the film thickness of the functional layer 20 can be ensured that the value of the formula (2) is equal to or greater than the lower limit, a sufficient photocatalytic effect can be expected. On the other hand, as the thickness of the functional layer 20 increases, the photocatalytic effect can be expected. However, since it becomes difficult to obtain desired spectral characteristics required for the multilayer film, the value of the expression (2) is set to the upper limit or less. It is desirable. In addition, Preferably, it is satisfy | filling the following formula | equation.
220 nm ≦ Tcat ≦ 600 nm (2 ′)
More preferably, it is satisfy | filling the following formula | equation.
250 nm ≦ Tcat ≦ 600 nm (2 ″)

The high refractive index layer H or the functional layer 20 adjacent to the uppermost layer 10 is preferably formed from an oxide (for example, TiO ₂ ) containing Ti as a main component. This is because Ti oxides such as TiO ₂ have a very high photocatalytic effect.

Preferably the top layer 10 is formed of SiO _2. At night or outdoors hardly incident UV light, in the oxide composed mainly of Ti hydrophilic effect is reduced, can exhibit a hydrophilic effect uppermost 10 even such a case by forming a SiO _2, also, Scratch resistance is also improved. When SiO ₂ is used for the uppermost layer 10, scratch resistance is improved by performing a heat treatment at 500 ° C. for 2 hours after film formation.

The uppermost layer 10 is preferably formed from a mixture of SiO ₂ and Al ₂ O ₃ (provided that the composition ratio of SiO ₂ is 90% by weight or more). Thereby, a hydrophilic effect can be exhibited even at night or outdoors, and scratch resistance is further enhanced by using a mixture of SiO ₂ and Al ₂ O ₃ . When a mixture of SiO ₂ and Al ₂ O ₃ is used for the uppermost layer 10, scratch resistance is improved by performing a heat treatment at 500 ° C. for 2 hours after film formation. Note that it is preferable to use IAD when a part or all of the uppermost layer 10 is formed. Thereby, scratch resistance can be improved.

Each layer of the multilayer film MC is formed by a vapor deposition method, and any one of the layers is preferably formed by IAD. Shift in spectral characteristics can be suppressed by film formation by IAD.

The multilayer film MC shown in FIG. 1A preferably has antireflection characteristics in the visible range. Here, the “visible region” means a wavelength range of 420 nm to 680 nm. In addition, the “antireflection characteristic” here means that the reflectance of light in the visible range is 2% or less, desirably 1% or less, and more desirably 0.5% or less. As a result, an antireflection effect in the visible region can be obtained, and it is preferable to use it for an imaging lens or the like.

The multilayer film MC shown in FIG. 1A or 1B preferably has a transflective or highly reflective characteristic in the visible range. Here, the “semi-transmission characteristic” means that the light transmittance in the visible range is 30% or more and 70% or less, and the “high reflection characteristic” means that the light reflectance in the visible range is 90% or more. It means that. As a result, a transflective mirror or a total reflection mirror in the visible range can be obtained.

The multilayer film MC shown in FIG. 1A or 1B preferably has antireflection properties in the near infrared region. Here, the “near infrared region” refers to a wavelength range of 700 nm to 2000 nm. Further, the “antireflection characteristic” here means that the reflectance of light in the near infrared region is 2% or less, desirably 1% or less, and more desirably 0.5% or less. Thereby, the antireflection effect in the near infrared region can be obtained.

The multilayer film MC shown in FIG. 1A or 1B preferably has a characteristic of reflecting near-infrared light by 70% or more. Thereby, a reflection mirror in the near infrared region and an IR cut filter can be obtained.

The multilayer film MC shown in FIG. 1A or 1B preferably has a characteristic of reflecting 70% or more of light in the ultraviolet region. Here, the “ultraviolet region” refers to a wavelength range of 350 nm to 400 nm. Note that the reflectance of light in the ultraviolet region is desirably 90% or more, and more desirably 95% or more. Thereby, a reflection mirror in the ultraviolet region and an ultraviolet cut filter are obtained.

The multilayer film MC may have a metal film or a dielectric multilayer film that reflects at least one of visible light and near-infrared light. Here, “reflection characteristics” means that the reflectance of light in the visible region or near infrared region is 70% or more, and desirably 85% or more.

When the metal film M is used, it is preferable that any one of Ag, Au, Cr, Al, Cu, and Ni is a main component. By using these appropriately, the usable area and the reflectance can be arbitrarily adjusted. “Main component” means that the content of the element is 51% by weight or more, preferably 70% by weight or more, more preferably 90% by weight, and still more preferably 100% by weight.

When the uppermost layer 10 is formed by the IAD method, it is preferable that the following conditional expression is satisfied.
12 nm ≦ D (iad) ≦ 30 nm (7)
here,
D (iad): Nano-indentation depth of the uppermost layer 10 formed by the IAD method

When the value of the expression (7) is below the upper limit, the ion assist power does not become too weak, the value D (iad) is stabilized, and the photocatalytic effect can be stabilized. On the other hand, if the value of the expression (7) is equal to or higher than the lower limit, the value D (iad) does not become too small even if the ion assist power is increased, and a high-density film is not formed and the photocatalytic effect is maintained. Can do.

When the uppermost layer 10 is formed by the IAD method, it is preferable that the following conditional expression is satisfied.
0.8 nm ≦ F (iad) ≦ 0.97 nm (8)
here,
F (iad): Filling rate of the uppermost layer 10 formed by the IAD method

Here, the filling rate indicates the proportion of atoms in the volume of the film. The calculation formula when the filling rate is F is shown below. A value F (noiad) described later is calculated in the same manner.
F = (nf1-nf2 + 0.33) /0.33
here,
nf1: Refractive index of the uppermost layer film after standing for 24 hours in an environment at a temperature of 25 ° C. and a humidity of 50% RH nf2: Refractive index of the uppermost layer film in a vacuum (during film formation)

When the value of the formula (8) is equal to or higher than the lower limit, the ion assist power does not become too weak, the value F (iad) is stabilized, and the photocatalytic effect can be stabilized. On the other hand, if the value of the formula (8) is below the upper limit, the value F (iad) does not become too large even if the ion assist power is increased, and a high-density film is not formed and the photocatalytic effect is maintained. Can do.

In addition, when the uppermost layer 10 is formed without using the IAD method, it is preferable that the following conditional expression is satisfied.
25 nm ≦ D (noad) ≦ 50 nm (9)
here,
D (noiad): nano-indentation depth of the uppermost layer 10 formed without using the IAD method

If the value of formula (9) is equal to or greater than the lower limit, even if the amount of oxygen introduced during film formation is reduced, the value D (noad) does not become too small and a high-density film is not formed, and the photocatalytic effect is maintained. be able to. On the other hand, if the value of equation (9) is less than or equal to the upper limit, even if the amount of oxygen introduced is increased, the value (noad) does not become too large, and a film having a density that can withstand optical applications can be formed.

When the uppermost layer 10 is formed without using the IAD method, it is preferable that the following conditional expression is satisfied.
0.7 ≦ F (noad) ≦ 0.87 (10)
here,
F (noad): Filling rate of the uppermost layer 10 formed without using the IAD method

If the value of equation (10) is less than or equal to the upper limit, even if the amount of oxygen introduced during film formation is reduced, the value F (noad) does not become too large, and a high-density film is not formed and the photocatalytic effect is maintained. be able to. On the other hand, when the value of the expression (10) is equal to or higher than the lower limit, even if the amount of oxygen introduced is increased, the value F (noiad) does not become too small, and a film having a density that can withstand optical use can be formed.

It is preferable that the optical product 100 satisfies the following conditional expression.
1.3 ≦ NL ≦ 1.5 (3)
1.9 ≦ NH ≦ 2.45 (4)
here,
NL: Refractive index at the d-line of the material of the low refractive index layer L NH: Refractive index at the d-line of the material of the high refractive index layer H

By satisfying the expressions (3) and (4), the optical product 100 having desired optical characteristics can be obtained. Here, the d line means light having a wavelength of 587.56 nm. As a material for the low refractive index layer L, SiO ₂ having a refractive index of 1.48 at d-line or MgF ₂ having a refractive index of 1.385 at d-line can be used. Further, Ta, Hf, Zr, and Nb oxides can be suitably used as the specific material that satisfies the formula (4).

When the glass substrate GL has optical power, it is preferable to satisfy the following conditional expression.
1.7 ≦ Ns ≦ 2.2 (5)
here,
Ns: Refractive index at d line of glass substrate GL

The optical performance of the optical product 100 can be enhanced with a compact configuration by satisfying the formula (5) as the refractive index at the d-line of the glass substrate GL in terms of optical design. By forming the multilayer film of the present invention on the glass substrate GL satisfying the formula (5), it can be used particularly for lenses exposed to the outside world, and achieves both excellent environmental resistance and optical performance. be able to.

On the other hand, when the glass substrate GL does not have optical power, it is preferable to satisfy the following conditional expression.
1.45 ≦ Ns ≦ 1.65 (6)
here,
Ns: Refractive index at d line of glass substrate GL

This is because, when the optical product 100 is applied as a building material such as a window glass, it is desirable to use a glass substrate GL having a refractive index of about 1.52, which is relatively inexpensive but has high strength.

According to this embodiment, the film thickness, density, film formation recipe of the multilayer film uppermost layer SiO ₂ and the TiO ₂ film thickness of the functional layer 20 adjacent to the uppermost layer 10 are optimized to maximize the photocatalytic effect. By providing the spectral characteristic adjusting layer, it is possible to provide a photocatalytic optical multilayer film having an arbitrary spectral characteristic in a wavelength band ranging from the visible region to the near infrared region.

The optical product 100 having the multilayer film can obtain a desired spectral characteristic while exhibiting a photocatalytic effect, and is suitably used for an in-vehicle lens, a communication lens, or a building material.

(Example)
Hereinafter, an example suitable for the above-described embodiment will be evaluated in comparison with a comparative example. In forming the multilayer films of the following examples and comparative examples, a film deposition apparatus BES-1300 manufactured by SYNCHRON Co., Ltd. was used, and NIS-175 was used as an ion source for IAD.

(Evaluation of functional layer thickness)
The inventors of the present invention formed a nine-layer multilayer film by vapor deposition on a glass substrate having an optical power (refractive index of 1.804) while changing the film thickness (d (nm)) of the functional layer. And used for the test. More specifically, as shown in Table 1, on a glass substrate TAF3 (manufactured by HOYA Co., Ltd .: refractive index 1.804), a low refractive index layer using SiO ₂ , OA600 (manufactured by Canon Optron Co., Ltd.). A high refractive index layer using a material and a functional layer using TiO ₂ were stacked in the order shown in Table 1 to form a film. As the uppermost layer, SiO ₂ was used. Table 1 shows the film formation recipe and film configuration of each layer (the first layer is the layer in contact with the glass substrate (glass substrate), the same applies hereinafter). In Table 1, “Layer” indicates a layer number, “Air” indicates a layer material, and “d” indicates a layer thickness (the same applies to the following tables).

OA600 in the table is a mixture of Ta ₂ O ₅ , TiO and Ti ₂ O ₅ , and the specific composition thereof is mainly composed of tantalum oxide as shown in Table 2.

The refractive index n (λ) in Table 1 and the table described later was obtained by the following formula. In this specification, the refractive index is measured by d-line (wavelength: 587.56 nm).
n (λ) = A ₀ + A ₁ / (λ−A ₂ )
Here, λ is the wavelength of the d-line, and A ₀ , A ₁ , and A ₂ of the materials used in the examples and comparative examples are the following values, respectively.
TAF3: A ₀ = 1.768, A ₁ = 14.724 (nm), A ₂ = 181.535 (nm)
B270 (white plate): A0 = 1.504, A1 = 6.912 (nm), A2 = 193.866 (nm)
M-BACD12: A0 = 1.561, A1 = 9.387 (nm), A2 = 1600.63 (nm)
_{_{OA600: A 0 = 2.014, A}} 1 = 31.680 (nm), A 2 = 233.891 (nm)
SiO ₂ : A ₀ = 1.460, A ₁ = 0 (nm), A ₂ = 0 (nm)
H4: A ₀ = 2.100, A ₁ = 0 (nm), A ₂ = 0 (nm)
TiO ₂ (functional layer): A ₀ = 2.013, A ₁ = 36.149 (nm), A ₂ = 284.651 (nm)
TiO ₂ :( high refractive index layer _{_{1) A 0 = 2.200, A}} 1 = 71.220 (nm), A 2 = 234.000 (nm)
TiO ₂ :( high refractive index layer _{_{2) A 0 = 2.230, A}} 1 = 71.220 (nm), A 2 = 234.000 (nm)

The film formation prescription is as shown in Table 1, but regarding the film formation of each layer, the film formation rate RATE (Å / SEC), the presence / absence of oxygen gas introduction, and the introduction amount are changed by changing the introduction amount. Two examples (test numbers 1-1 to 1-3) and two comparative examples (test numbers 1-4 and 1-5) were prepared and used for the following tests. Further, the film thickness TL of the uppermost layer was fixed at around 85 nm. IAD was not used for film formation. The heating temperature was 340 ° C., and the starting vacuum was 3.00E-03 Pa (3.00 × 10 ⁻³ Pa). 2 to 6 are diagrams showing the spectral characteristics of the multilayer films of test numbers 1-1 to 1-5. In the figure, the vertical axis represents reflectance (unit:%) and the horizontal axis represents wavelength (unit: nm) (the same applies to the following figures).

As an evaluation item, “photocatalytic effect measurement” is performed by irradiating a test sample with a black light (model number BL20) manufactured by YAZAWA at a distance of 30 mm from the test sample and irradiating with UV light for 5 minutes. Was used to evaluate the color change step by step. Here, a sample having a minimal color change has no photocatalytic effect (evaluation x), and a sample having a large color change has a photocatalytic effect (evaluation o) (see Table 8).

Moreover, as an evaluation item, “nanoindentation indentation depth” is a single layer film formed on a glass plate with a thickness of 200 nm, and as a nanoindentation measuring device, a miniature indentation hardness tester manufactured by Elionix A ridge interval 115 ° triangular pyramid diamond indenter was attached to ENT-2100, and this was pressed against the membrane for measurement. In the measurement, the indenter gives a load at a load speed of 0.2 mgf / sec, holds the maximum load of 0.98 mN for 1 second, then unloads at the same load speed, and determines the indenter indentation depth obtained from a series of operations. The indentation depth when the maximum load was reached was obtained from the load curve.

(Consideration of evaluation results)
For the multilayer films of test numbers 1-1 to 1-3, the evaluation of the photocatalytic effect measurement was ○ when the film thickness Tcat of the functional film was 300 nm to 582 nm (see Table 8 described later). In addition, as shown in FIGS. 2 to 4, each multilayer film has a reflectance of 1.5% or less mainly in the visible region (with an allowable value of 2%), realizing good spectral characteristics as a visible region antireflection film. is doing.

On the other hand, the multilayer film with the test numbers 1 to 4 achieves a good spectral characteristic with a reflectance of 1% or less mainly in the visible region as shown in FIG. 5, but the film thickness Tcat of the functional film. Was 85 nm, evaluation of photocatalytic effect measurement was x. This can be attributed to the fact that the film thickness of the functional film was too thin to sufficiently exhibit the photocatalytic function.

On the other hand, for the multilayer film of test number 1-5, when the film thickness Tcat of the functional film was 814 nm, the evaluation of the photocatalytic effect measurement was ○, but the reflectance was visible in the visible region as shown in FIG. It can be seen that the allowable value exceeds 2% and a sufficient antireflection effect is not obtained. That is, it can be seen that the spectral characteristics deteriorate when the thickness Tcat of the functional film is too thick.

From the above results, it can be said that the film thickness of the functional film is preferably at least 220 nm or more and 700 nm or less in order to ensure a good balance between the photocatalytic effect that tends to be a trade-off relationship and the spectral characteristics.

(2) The present inventors formed a 15-layer or 7-layer multilayer film on a glass substrate having optical power by a vapor deposition method while changing the spectral characteristics, and used for the test. More specifically, as shown in Table 3, on a glass substrate TAF3 (manufactured by HOYA: refractive index 1.804) or M-BACD12 (manufactured by HOYA: refractive index 1.580), SiO 2 A low refractive index layer using ₂ , a high refractive index layer using OA600 (material manufactured by Canon Optron Co., Ltd.), and a functional layer using TiO ₂ were laminated in the order shown in Table 3. As the uppermost layer, SiO ₂ was used. Table 3 shows the film formation recipe and film configuration of each layer.

The film formation recipe is as shown in Table 3. Regarding the film formation of each layer, four examples (test numbers 2-1) were prepared by changing the film formation rate RATE (Å / SEC) and the amount of oxygen gas introduced. 2-4) were prepared, and the photocatalytic effect and the spectral characteristics were evaluated. IAD was not used for film formation. Further, the film thickness TL of the uppermost layer was set to 97 nm to 228 nm. The heating temperature was 340 ° C. and the starting vacuum was 3.00E-03 Pa, respectively. 7 to 10 are diagrams showing the spectral characteristics of the multilayer films of test numbers 2-1 to 2-4.

Regarding the multilayer films of test numbers 2-1 to 2-4, when the film thickness Tcat of the functional film was 244 nm to 427 nm, the evaluation of the photocatalytic effect measurement was ○ (see Table 8 described later). In addition, as shown in FIG. 7, the multilayer film of test number 2-1 has a reflectance of 1% or less mainly in the near infrared region (wavelength 700 nm to 1050 nm), and has good spectral characteristics as a near infrared region antireflection film. Realized. As shown in FIG. 8, the multilayer film of test number 2-2 has a reflectance of 1% or less mainly in the near infrared region (wavelength 1200 nm to 1800 nm), and realizes a good spectral characteristic as a near infrared region antireflection film. ing. As shown in FIG. 9, the multilayer film of Test No. 2-3 has a reflectance of 2% or less mainly in the visible region (450 nm to 850 nm) and realizes good spectral characteristics as a visible region antireflection film. As shown in FIG. 10, the multilayer film of Test No. 2-4 has a reflectance of 1.5% or less mainly in the near infrared region (wavelength 1200 nm to 1800 nm), and has good spectral characteristics as a near infrared region antireflection film. Realized.

(3) The present inventors formed a multilayer film of 8, 10, or 12 layers by a vapor deposition method on a glass substrate having no optical power and changing the spectral characteristics, and used for the test. More specifically, as shown in Table 4, on a glass substrate B270 (manufactured by SCHOTT: refractive index 1.522, also referred to as a white plate), a metal film, a low refractive index layer using SiO ₂ , OA600 ( A high refractive index layer using a material manufactured by Canon Optron Co., Ltd. and a functional layer using TiO ₂ having a refractive index of 2.032 were stacked in the order shown in Table 4 to form a film. As the uppermost layer, SiO ₂ was used. Table 4 shows the film formation recipe and film configuration of each layer.

The film formation prescription is as shown in Table 4. Regarding the film formation of each layer, four examples (provided) were prepared by changing the film formation rate RATE (Å / SEC), the amount of oxygen gas introduced, and the material of the metal film. Test numbers 3-1 to 3-4) were prepared, and the photocatalytic effect and the spectral characteristics were evaluated, respectively. The metal film of test number 3-1 is Al, the metal film of test number 3-2 is Cr, the metal film of test number 3-3 is Cu, and the metal of test number 3-4 The film was Ni. IAD was not used for film formation. The film thickness TL of the uppermost layer was 77 nm to 89 nm. The heating temperature was 340 ° C. and the starting vacuum was 3.00E-03 Pa, respectively. 11 to 14 are diagrams showing the spectral characteristics of the multilayer films of test numbers 3-1 to 3-4.

Regarding the multilayer films of test numbers 3-1 to 3-4, when the film thickness Tcat of the functional film was 300 nm to 351 nm, the photocatalytic effect measurement was evaluated as “good” (see Table 8 described later). Further, as shown in FIG. 11, the multilayer film of test number 3-1 has a reflectance of 75% or more mainly from the visible region to the near infrared region (wavelength of 400 nm to 1950 nm), and has good spectral characteristics as a broadband reflection mirror. Realized. As shown in FIG. 12, the multilayer film of test number 3-2 mainly has a reflectance of 70% or more in the visible region (wavelength 400 nm to 650 nm), and realizes good spectral characteristics as a visible region reflecting mirror. As shown in FIG. 13, the multilayer film of test number 3-3 has a reflectance of 85% or more mainly from the visible region to the near-infrared region, and realizes good spectral characteristics as a broadband reflecting mirror. As shown in FIG. 14, the multilayer film of the test number 3-4 mainly has a reflectance of 75% or more in the visible region (wavelength 400 nm to 650 nm), and realizes good spectral characteristics as a visible region reflecting mirror.

(4) The present inventors formed a multilayer film of 26 to 199 layers on a glass substrate having no optical power by a vapor deposition method while changing the spectral characteristics, and used for the test. More specifically, as shown in Tables 5 to 7, on a glass substrate B270 (white plate) (manufactured by SCHOTT: refractive index 1.522), a low refractive index layer using SiO ₂ , H4 (MERCK) Ltd.: lanthanum titanate (LaTiOx), TiO ₂ having a refractive index 2.401, TiO ₂ having a refractive index 2.431, or OA600 high refractive index layer using the (Canon Optron Ltd. material), the refractive index 2. 132 functional layers using TiO ₂ were stacked in the order shown in Table 5. SiO ₂ was used as the uppermost layer, and the film formation recipe and film configuration of each layer are shown in Tables 5-7.

The film formation prescriptions are as shown in Tables 5 to 7. However, regarding the film formation of each layer, the film formation rate RATE (Å / SEC), the amount of oxygen gas introduced, and when using IAD, the prescription is set, Four examples (test numbers 4-1 to 4-4) were prepared, and the photocatalytic effect and the spectral characteristics were evaluated. Further, the film thickness TL of the uppermost layer was set to 86 nm to 250 nm. The heating temperature was 340 ° C. and the starting vacuum was 3.00E-03 Pa, respectively. 15 to 18 are diagrams showing the spectral characteristics of the multilayer films of test numbers 4-1 to 4-4. In Test No. 4-2, a dielectric multilayer film is used as a film that reflects light.

“APC” means that the partial pressure is adjusted by the abbreviation of “Auto Pressure Control”, and “SCCM” is the abbreviation of “standard cc / min”, which is 1 atm (atmospheric pressure 1013 hPa) at 0 ° C. for 1 minute. It is a unit indicating how many cc flowed around.

Regarding the multilayer films of the test numbers 4-1 to 4-4, when the film thickness Tcat of the functional film was 392 nm to 472 nm, the photocatalytic effect measurement was evaluated as “good” (see Table 8 described later). Further, as shown in FIG. 15, the multilayer film of test number 4-1 mainly has a reflectance of around 50% in the visible region (wavelength 360 nm to 700 nm), and realizes good spectral characteristics as a visible region semi-transmissive film. ing. As shown in FIG. 16, the multilayer film of Test No. 4-2 has a reflectance of 95% or more mainly in the visible region (wavelength 400 nm to 750 nm), and realizes good spectral characteristics as a visible region reflecting mirror. As shown in FIG. 17, the multilayer film of test number 4-3 mainly has a reflectance of 85% or more in the ultraviolet region (400 nm or less) and a reflectance of 2% or less in the visible region (wavelength 420 nm to 700 nm). In addition, a good spectral characteristic is realized as a UV-IR cut filter having a wavelength selectivity with a reflectance of 95% or more in the near infrared region (800 nm to 1150 nm). As shown in FIG. 18, the multilayer film of test number 4-4 mainly has a reflectance of 95% or more in the ultraviolet region (400 nm or less) and a reflectance of 5% or less in the visible region (wavelength 400 nm to 750 nm). In addition, excellent spectral characteristics are realized as a UV-IR cut filter having a wavelength selectivity with a reflectance of 88% or more in the near infrared region (800 nm to 1950 nm).

(5) Summary The results of the above studies are shown in Table 8 separately for Examples and Comparative Examples. here,
Tcat: film thickness (nm) of the high refractive index layer or functional layer adjacent to the uppermost layer
TL: film thickness of the top layer (nm)
NL: Refractive index at the d-line of the material of the low refractive index layer NH: Refractive index at the d-line of the material of the high refractive index layer Ns: Refractive index at the d-line of the glass substrate.

In Table 8, “indentation depth range” indicates conditional expression (7) or (9), and “filling ratio range” indicates conditional expression (8) or (10).

Claims

In an optical product having a glass substrate on which a multilayer film of three or more layers is formed,
The multilayer film is configured to adjust the spectral characteristics of the optical product by using a combination of at least one low refractive index layer and at least one high refractive index layer.
The uppermost layer farthest from the glass substrate is the low refractive index layer,
The high refractive index layer adjacent to the uppermost layer is a functional layer mainly composed of a metal oxide having a photocatalytic function,
Optical product that satisfies the following conditional expression.
60 nm ≦ TL ≦ 350 nm (1)
220 nm ≦ Tcat ≦ 700 nm (2)
here,
TL: film thickness of the uppermost layer Tcat: film thickness of the functional layer
The optical product according to claim 1, wherein the functional layer is formed of an oxide containing Ti as a main component.
The optical product according to claim 1, wherein the uppermost layer is made of SiO 2 .
The optical product according to claim 1, wherein the uppermost layer is formed of a mixture of SiO 2 and Al 2 O 3 .
5. The optical product according to claim 1, wherein each layer of the multilayer film is formed by a vapor deposition method, and any one of the layers is formed by ion-assisted deposition.
The optical product according to any one of claims 1 to 5, wherein the uppermost layer is formed by ion-assisted deposition and satisfies the following conditional expression.
12 nm ≦ D (iad) ≦ 30 nm (7)
here,
D (iad): Nano-indentation depth of the uppermost layer formed by ion-assisted deposition
The optical product according to any one of claims 1 to 6, wherein the uppermost layer is formed by ion-assisted deposition and satisfies the following conditional expression.
0.8 nm ≦ F (iad) ≦ 0.97 nm (8)
here,
F (iad): Filling rate of the uppermost layer formed by the ion-assisted deposition
The optical product according to any one of claims 1 to 5, wherein the uppermost layer is formed without using ion-assisted deposition and satisfies the following conditional expression.
25 nm ≦ D (noad) ≦ 50 nm (9)
here,
D (noad): Nano-indentation depth of the uppermost layer formed without using the ion-assisted deposition
The optical product according to claim 1, wherein the uppermost layer is formed without using ion-assisted deposition and satisfies the following conditional expression.
0.7 ≦ F (noad) ≦ 0.87 (10)
here,
F (noad): Filling rate of the uppermost layer formed without using the ion assist deposition
The optical product according to any one of claims 1 to 9, wherein the multilayer film has antireflection characteristics in a visible range.
The optical product according to any one of claims 1 to 9, wherein the multilayer film has a semi-transmissive or highly reflective characteristic in a visible range.
The optical product according to any one of claims 1 to 11, wherein the multilayer film has an antireflection characteristic in a near infrared region.
The optical product according to any one of claims 1 to 11, wherein the multilayer film has a characteristic of reflecting near-infrared light by 70% or more.
The optical product according to any one of claims 1 to 13, wherein the multilayer film has a characteristic of reflecting 70% or more of ultraviolet light.
The optical product according to any one of claims 1 to 14, wherein the multilayer film has a metal film that reflects at least one of visible light and near-infrared light.
The optical product according to claim 15, wherein the metal film is mainly composed of Ag, Au, Cr, Al, Cu, or Ni.
The optical product according to any one of claims 1 to 16, which satisfies the following conditional expression.
1.3 ≦ NL ≦ 1.5 (3)
1.9 ≦ NH ≦ 2.45 (4)
here,
NL: Refractive index at the d-line of the material of the low refractive index layer NH: Refractive index at the d-line of the material of the high refractive index layer
The optical product according to any one of claims 1 to 17, wherein the glass substrate has optical power and satisfies the following conditional expression.
1.7 ≦ Ns ≦ 2.2 (5)
here,
Ns: Refractive index at d-line of the glass substrate
The optical product according to any one of claims 1 to 18, wherein the glass substrate does not have optical power and satisfies the following conditional expression.
1.45 ≦ Ns ≦ 1.65 (6)
here,
Ns: Refractive index at d-line of the glass substrate