JPH05107402A - Optical member having antireflection film - Google Patents

Abstract

PURPOSE:To provide an optical member having an antireflection film in which a synthetic resin substrate does not discolor even though a TiO2 layer exhibiting a low visual reflective characteristic and having a high refractivity formed thereon, countless dents and creases can hardly develop on the antireflection film even though the TiO2 layer is formed on an optical substrate made of synthetic resin such as polyurethane resin which is likely to be deformed with time. CONSTITUTION:In an optical member incorporating a laminated antireflection film in which a TiO2 layer having an optical film thickness of lambda/2 (where lambdais a designed wave length in a range from 500 to 550nm) is formed over a synthetic resin substrate, the TiO2 layer is formed by irradiating an oxygen ion beam onto the substrate, having a refractive index in a range of 2.25 to 2.35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member having an antireflection film.

[0002]

2. Description of the Related Art It is well known to provide an antireflection film on a synthetic resin substrate in order to reduce the surface reflection of the synthetic resin substrate. Further, in order to obtain a luminous reflectance as low as possible, a TiO ₂ layer which is a high refractive index material is used as a high refractive index layer having a thickness of λ / 2, and when forming a TiO ₂ layer, oxygen ions are used. It is also known to deposit TiO ₂ while irradiating a synthetic resin substrate with a beam. As an example of an optical member having a reflection preventing effect provided with a TiO ₂ layer on a synthetic resin substrate, for example, in Japanese Patent Laid-Open No. 2-39101, a substrate is a polyurethane lens, and a SiO ₂ layer is formed on the polyurethane lens. 1 layer [refractive index 1.47, film thickness 3/2 λ (λ is 550 nm; the same applies hereinafter), ZrO
₂ and a second layer of SiO ₂ equivalent film [refractive index 1.
80, film thickness λ / 4], a third layer composed of a TiO ₂ layer formed while irradiating the substrate with an oxygen ion beam [refractive index 2.40, film thickness λ / 2], a fourth layer composed of SiO ₂ . An optical member having an antireflection film formed by sequentially laminating layers [refractive index 1.47, film thickness λ / 4] is disclosed. A feature of the present invention is that the third TiO ₂ layer has a thickness of λ / 2 and a refractive index of 2.40, which is an upper limit, to obtain a low luminous reflectance.

[0003]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
The optical member disclosed in Japanese Unexamined Patent Publication No. 39101 is Ti
Since the refractive index of the O ₂ layer is set to the upper limit of 2.40, it is necessary to irradiate the substrate with a high energy oxygen ion beam. Therefore, there is a problem that the synthetic resin substrate is easily colored by the irradiation of the high energy oxygen ion beam. If the refractive index of the TiO ₂ layer is set to 2.40, the T
Due to the shorter intermolecular distance of iO ₂ , the Ti
Since the molecular state of O ₂ is dense, a strong internal stress is generated in the TiO ₂ layer, and in the case of a synthetic resin such as polyurethane resin that is susceptible to microdeformation over time, countless dents and wrinkles occur in the antireflection film. It has a problem in that it is easy to look and is not preferable in terms of optics. Therefore, the above-mentioned optical member has a problem that it is difficult to apply it to a lens for eyeglasses. The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent the synthetic resin substrate from being colored even when a TiO ₂ layer, which is a high refractive index layer, is formed, and to be minute over time like a polyurethane resin. Provided is an optical member having a TiO ₂ layer which is resistant to countless dents and wrinkles in an antireflection film even when an TiO ₂ layer is formed on an optical substrate made of a synthetic resin which is easily deformed, and which further exhibits a low luminous reflectance property. Especially.

[0004]

The above-mentioned objects have been achieved by the invention described below. That invention is an optical member which has been subjected to multilayer antireflection film having a TiO ₂ layer of the optical film thickness of lambda / 2 at the time when the design wavelength to the synthetic resin substrate was 500 nm and 550 nm, the TiO ₂ layer is the An optical member having an antireflection film, which is formed while irradiating an oxygen ion beam on a substrate and has a refractive index range of 2.25 to 2.35.

The present inventor refracts the irradiation energy amount of the ion beam to the synthetic resin substrate by setting the refractive index of the TiO ₂ layer, which is a high refractive index layer having a thickness of λ / 2, to 2.25 to 2.35. It has been found that the TiO ₂ layer having a rate of 2.40 can be made smaller than the TiO ₂ layer, and the coloring of the synthetic resin substrate can be suppressed. Further, the refractive index of the TiO ₂ layer is 2.25 to 2.
Compared to the TiO ₂ layer having a refractive index 2.40 by 35, the molecular state of the layer of TiO ₂ than the distance between the TiO ₂ molecules becomes longer becomes sparse state, the internal stress of the TiO ₂ layer I found that I can keep it low.
It has been found that by doing so, even if an antireflection film having a TiO ₂ layer is applied on a polyurethane resin that is susceptible to minute changes over time, it is possible to prevent the formation of dents and wrinkles in the antireflection film without impairing the luminous reflection properties. It was

Next, with the above-mentioned film thickness λ / 2, the refractive index is 2.25.
The TiO ₂ layer of 2.35 will be described. This layer is
A method of depositing titanium dioxide by blasting titanium or an oxide thereof (titanium monoxide, titanium dioxide, etc.) toward the substrate while irradiating the substrate with an oxygen ion beam while heating the synthetic resin substrate at 50 to 120 ° C. Is formed by.
The reason why it is preferable to heat the synthetic resin substrate to 50 to 120 ° C. in this forming method is that the temperature is less than 50 ° C.
This is because the hardness of the formed TiO ₂ layer is likely to be insufficient, and on the other hand, when the temperature exceeds 120 ° C., the plastic base material may be thermally deformed and distortion or the like may occur. Other conditions of this forming method (for example, a method of irradiating a substrate with an oxygen ion beam, a method of vaporizing titanium or its oxide as a raw material, etc.)
Is appropriately selected from the conditions usually adopted,
The oxygen ion current density at the time of irradiating the substrate with the ion beam is 5 in order to make the refractive index of the TiO ₂ layer 2.25 to 2.35.
The range of ˜15 μA / cm ² is preferable. Λ in the present invention
The film thickness of / 2 corresponds to the film thickness of the high refractive index layer of λ / 2, which is a three-layer film of λ / 4-λ / 2-λ / 4, and the substantial film thickness is 0. It is in the range of 42λ to 0.58λ. The reason why the thickness of this TiO ₂ layer is specified to be λ / 2 is that an antireflection film having good low luminous reflectance characteristics can be obtained by combining the refractive index with other refractive index layers and the film thickness. Because.

The film constitution of the antireflection film of the present invention is not particularly limited as long as the above conditions are satisfied, but in view of practical use, a three-layer film of λ / 4-λ / 2-λ / 4, λ / 4-λ
A multilayer film in which / 2-λ / 4 is modified is preferable. This λ /
As an example of a multilayer film in which 4-λ / 2-λ / 4 is modified, 3
It can be mentioned that λ / 4 of the first layer counted from the layer film substrate is a three-layer symmetrical equivalent film or a two-layer composite film. Also, the refractive index of each layer of λ / 4-λ / 2-λ / 4,
There is a relationship between the refractive index of the substrate and the refractive index of the medium as shown in the following formula. Even if the refractive index of the substrate changes, λ / 4 or the third layer of the first layer is counted from the substrate of the antireflection film. By adjusting the refractive index of λ / 4 of the layer, it is possible to obtain an optical member having a good low luminous reflectance property. N ₁ ² No = N ₃ ² Ns N ₀ : Refractive index of substrate N ₁ : Refractive index of first layer of antireflection film counted from substrate N ₃ : Refractive index of third layer of antireflection film counted from substrate Ns: Refractive index of medium Incidentally, the method for forming layers other than the TiO ₂ layer described above is not particularly limited, and a vacuum deposition method, an ion beam assist method, a sputtering method, or the like is used.

Examples of the synthetic resin used in the optical member of the present invention include methyl methacrylate homopolymer, copolymers containing methyl methacrylate and one or more other monomers as monomer components, diethylene glycol bisallyl carbonate homopolymer, and diethylene glycol. Copolymers containing bisallyl carbonate and one or more other monomers as monomer components, sulfur-containing copolymers, halogen-containing copolymers, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, etc. Polymers of The polyurethane copolymer referred to here is a copolymer formed by reacting a polyisocyanate compound with a polythiol compound and / or a polyol compound.

In the present invention, a hard coat layer containing an organosilicon polymer and a commonly known underlayer can be interposed between the synthetic resin substrate and the antireflection film. The optical member having the antireflection film of the present invention can be used not only for spectacle lenses, but also for camera lenses, automobile window glasses, optical filters attached to displays of word processors, and the like.

[0010]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The physical properties of the optical members having the antireflection film obtained in Examples and Comparative Examples were measured by the test methods described below.

(A) Scratch resistance test: # 0000 steel wool was used to reciprocate the surface 1 times.
The scratch resistance was evaluated by rubbing 0 times as follows. A: Slightly scratched B: Many scratches C: Film peeling occurs

(B) Luminous reflectance and luminous transmittance Luminous reflectance and luminous transmittance were determined by using Hitachi U3410 type self-recording spectrophotometer.

(C) Coloring rate The coloring rate (%) was determined by the following formula. Coloring rate (%) = 100 (%)-[luminous reflectance (%) + luminous transmittance (%)]

(D) Appearance The following items were visually inspected, and those not corresponding to the items were judged to be good, and those corresponding to them were judged to be defective. (I) The optical member is colored. (Ii) Dimples and wrinkles are visible in the antireflection film.

(E) Adhesion test In accordance with JIS-Z-1522, 10 × 10 goggles were made, and a peeling test was performed three times with a cellophane adhesive tape, and the number of gobangs remaining was counted.

Example 1 First, a polyurethane lens (nd = 1.60, νd = 36) obtained by polymerizing m-xylene diisocyanate and pentaerythritol tetrakispropyl pionate was prepared as a synthetic resin substrate on which an antireflection film was applied. did.

(I) Formation of Hard Coat Layer The polyurethane lens is dipped in a coating solution containing tin oxide sol coated with 50 mol% of tungsten oxide sol and 50 mol% of γ-glycidoxypropyltrimethoxysilane. Then, it was cured to provide a hard coat layer.

(Ii) Formation of Underlayer and Antireflection Film A plastic lens having the hard coat layer is formed into a layer of 80
After heating to ℃, by vacuum evaporation method (vacuum degree 2 × 10 ^-5 Torr), SiO ₂ layer (refractive index 1.46, film thickness 0.103λ), TiO ₂ layer (refractive index 2.30, film thickness 0.030λ), an underlayer consisting of a SiO ₂ layer (refractive index 1.46, film thickness 0.596λ), and a TiO ₂ layer (refractive index 2.30, film thickness) on this underlayer. 0.05
7λ), SiO ₂ layer (refractive index 1.46, film thickness 0.058
λ) a first low-refractive index layer formed of a two-layer equivalent film,
On top of this low refractive index layer, a high refractive index layer consisting of a TiO ₂ layer (refractive index 2.30, film thickness 0.466λ), and a second low refractive index consisting of a SiO ₂ layer on this high refractive index layer. Layer (refractive index 1.
44, and a film thickness of 0.25λ) were laminated to produce an optical member having an antireflection film. When forming the TiO ₂ layer, the polyurethane lens substrate is irradiated with an oxygen ion beam at an oxygen ion current density of 10 μA / cm ² while irradiating Ti.
O ₂ was blown toward the substrate to form a TiO ₂ layer. The results are shown in Table 2. As can be seen from Table 2, the abrasion resistance was excellent, the luminous reflectance was 0.18%, which was also excellent in the antireflection effect, and the lens was not colored, and the antireflection film had no dents or wrinkles. The design wavelength is λ = 520n
m.

Comparative Example 1 As a comparison of Example 1, Comparative Example 1 will be given. A comparison with Example 1 was performed by setting the refractive index of the TiO ₂ layer of the high refractive index layer to 2.40. When forming this TiO ₂ layer, a polyurethane resin base material of the same material used in Example 1 was irradiated with an oxygen ion beam at an oxygen ion current density of 25 μA / cm ² to obtain a high refractive index of 2.40. A plastic lens having an antireflection film was produced in the same manner as in Example 1 except that a TiO ₂ layer as a refractive index layer was formed. The results are shown in Table 1. As can be seen from Table 1, the luminous reflectance was 0.18%, which was excellent in the antireflection effect, but the lens was colored, and the antireflection film had dents and wrinkles, which were unfavorable in appearance.

Example 2 Instead of the polyurethane lens used in Example 1, diethylene glycol bisallyl carbonate lens (nd =
1.499, νd = 49), and the antireflection film was formed in the same manner as in Example 1 except that 50 mol% γ-glycidoxypropyltrimethoxysilane and 50 mol% colloidal silica were used as the coating liquid. A plastic lens having is obtained. The results are shown in Table 2. As can be seen from Table 2, like the plastic lens having the antireflection film of Example 1, it has excellent scratch resistance and a luminous reflectance of 0.18%.
And the antireflection effect was excellent, and the lens was not colored, and the antireflection film had no dents or wrinkles.

Comparative Example 2 Comparative Example 2 will be given as a comparison with Example 2. A comparison with Example 1 was performed by setting the refractive index of the TiO ₂ layer of the high refractive index layer to 2.40. When forming the TiO ₂ layer of the high refractive index layer, the diethylene glycol bisallyl carbonate lens base material of the same material used in Example 2 was irradiated with an oxygen ion beam at an oxygen ion current density of 25 μA / cm ² to be refracted. Example 2 except that a TiO ₂ layer having a rate of 2.40 was formed.
A plastic lens having an antireflection film was prepared in the same manner as in. The results are shown in Table 2. As can be seen from Table 2, the luminous reflectance was 0.18%, which was excellent in the antireflection effect, but the lens was colored, which was unfavorable in appearance.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

According to the present invention, Ti which is a high refractive index material
Even when O ₂ is used as a vapor deposition material, the substrate does not become colored, and even when a TiO ₂ layer is formed on a synthetic resin substrate that is susceptible to microdeformation over time, such as polyurethane resin, countless dents and dents are formed in the antireflection film. It was possible to provide an optical member having an antireflection film that is less likely to generate wrinkles and exhibits low luminous reflectance properties.

Claims (4)

[Claims] 1. λ = 500 nm to 55 on a synthetic resin substrate.
Ti with an optical film thickness of λ / 2 when the design wavelength is 0 nm
An optical member provided with a multilayer antireflection film having an O ₂ layer, wherein the TiO ₂ layer is formed while irradiating the substrate with an oxygen ion beam, and the refractive index range of the layer is 2.25 to.
An optical member having an antireflection film, which is 2.35. 2. The antireflection film according to claim 1, wherein the multilayer antireflection film includes the TiO ₂ layer as a high refractive index layer and a SiO ₂ layer as a low refractive index layer. Optical member. 3. The optical member having an antireflection film according to claim 1, wherein the synthetic resin substrate is a polyurethane resin. 4. The optical member according to claim 1, wherein the optical member is an eyeglass lens.