JPH06273601A - Antireflection film of optical parts made of synthetic resin - Google Patents

Abstract

PURPOSE:To improve the durability of the antireflection films of optical parts made of a synthetic resin. CONSTITUTION:An under coat 2 essentially consisting of a silicon dioxide SiOx (2>x>1) and having 200 to 300nm film thickness is formed on the surface 1a of a plastic lens 1 and multilayered films 3 are laminated on this under coat 2. These multilayered films 3 consist of thin films 3a, 3c of a first layer and third layer formed out of high-refractive index materials essentially consisting of TiO2 or ZrO2 or a mixture composed thereof and thin films 3b, 3d of a second layer and fourth layer 4 made of low-refractive index materials essentially consisting of the silicon dioxide SiOx (2>=x>=1). The under coat 2 enhances the adhesion property between the multilayered films 3 and the surface 1a of the plastic lens 1 without impairing the antireflection characteristics of the multilayered films 3 and improves the durability, such as wear resistance and chemical resistance, thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film of a synthetic resin optical component for preventing surface reflection of a synthetic resin optical component such as a plastic lens.

[0002]

2. Description of the Related Art Conventionally, in order to prevent surface reflection of optical parts such as optical lenses, a thin film of silicon oxide SiO _x is provided, or ZrO ₂ , TiO ₂ , CaO ₂ ,
Thin film of high refractive index material such as Ta ₂ O ₅ and MgF ₂ , SiO ₂
It has been proposed a method of providing an antireflection film composed of a multilayer film in which thin films of low refractive index materials such as
In optical parts made of synthetic resin such as plastic lenses, since it is necessary to supplement the softness and chemical resistance of the surface, a thin film of silicon oxide SiO _x having high hardness and excellent chemical resistance. Is often used as the first or intermediate layer of the antireflection film.

As an example, in Japanese Patent Laid-Open No. Sho 60-98401, a quarter-wave film (hereinafter referred to as "λ") made of SiO on the surface of an acrylic lens has a refractive index n of 1.55 or more and a thickness of 89 nm or less. / 4 film ”) is deposited and M is deposited on it.
A two-layer antireflection film formed by laminating λ / 4 films made of gF ₂ and having a refractive index n = 1.38 has been proposed, and Japanese Patent Laid-Open No. 60-225101 discloses SiO 2 as the first layer. ₂
A thin film having a refractive index n = 1.47, a film thickness d = 354 nm, and an optical film thickness nd = λ ₀ is formed by vacuum vapor deposition, and a refractive index n = 2.05 made of Ta ₂ O ₅ is sequentially formed on the thin film. ,
Optical film thickness nd = a thin film of 0.057λ _0, the refractive index n = 1.47, which consists of SiO _2, a thin film of an optical film thickness d = 0.11λ _0, the refractive index n = 2 consisting of Ta ₂ O _5. 05, an antireflection film composed of a five-layer film in which a thin film having an optical film thickness nd = 0.538λ _{0 and} a thin film made of SiO _{2 having} a refractive index n = 1.47 and an optical film thickness nd = 0.258λ ₀ are laminated. Have been proposed (design wavelength λ ₀ = 520 nm), and
-116101, a methacrylic resin cast substrate has a refractive index n = 1.60 made of SiO _x as a first layer,
Optical film thickness _{nd = (λ 0/4)} × 20% (d = 17~18
(nm) thin film is formed by vacuum evaporation, and T
Refractive index of iO ₂ n = 1.95, optical film thickness nd =
(Λ _0/4) × 20% of the film, the refractive index n = 1.45, which consists of SiO _2, the optical thickness _{nd = (λ 0/4)} × 40%
A thin film of a refractive index n = 2.0 consisting of TiO _2, the optical thickness _{nd = (λ 0/4)} × 70% of the film, the refractive index n = 1.45, which consists of SiO _2, an optical film thickness nd = (λ _0/4)
There has been proposed an antireflection film (design wavelength λ ₀ = 550 to 570 nm) composed of a five-layer film in which thin films of × 95% are laminated.

[0004]

However, according to the above-mentioned conventional techniques, there is no fear that the performance is significantly deteriorated when used in a limited environment such as a living space.
When exposed to severe temperature conditions outdoors or used for a long time in an environment where temperature and humidity change greatly,
Abrasion resistance and chemical resistance may be deteriorated, and cracks (film cracks) may occur in the antireflection film due to thermal strain of the base material of the synthetic resin and the like, and in extreme cases, film peeling may occur.

As a result of a quality evaluation test described later, the above-mentioned Japanese Patent Laid-Open No. 60-98401 and Japanese Patent Laid-Open No. 3-1.
The antireflection film described in Japanese Patent No. 16101 was found to have insufficient abrasion resistance and chemical resistance immediately after film formation, and the antireflection film described in Japanese Patent Application Laid-Open No. 60-225101 It has been found that it has an absorptivity of about 3% with respect to light in the visible region and has a problem in its optical characteristics.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, is excellent in abrasion resistance, chemical resistance and optical characteristics, and is under severe temperature and humidity conditions, or It is an object of the present invention to provide an antireflection film for synthetic resin optical parts that does not cause the above-mentioned characteristics to deteriorate or cause cracks or film peeling even when used for a long time in an environment where the temperature and humidity greatly change. It is a thing.

[0007]

In order to achieve the above object, the antireflection film of the present invention mainly comprises a silicon oxide SiO _x (2>x> 1) formed on the surface of a synthetic resin optical component. It is characterized by comprising an undercoat having a film thickness of 200 nm to 300 nm as a component, and a repeating multilayer film having an antireflection property formed on the undercoat.

Further, the repeating multilayer film is made of TiO ₂ or Zr.
A thin film composed of a high refractive index material containing O ₂ or a mixture thereof as a main component and a thin film composed of a low refractive index material containing SiO _x (2 ≧ x ≧ 1) as a main component are alternately laminated. Good.

[0009]

According to the above apparatus, a silicon oxide SiO _x having high hardness, excellent chemical resistance and adhesiveness to synthetic resin.
By using a thin film containing (2>x> 1) as a main component as an undercoat that does not contribute to the antireflection property,
Improves wear resistance and chemical resistance of antireflection film and adhesion to synthetic resin. Undercoat thickness of 200
When the thickness is not less than nm, the above-mentioned abrasion resistance and chemical resistance can be sufficiently improved, and in addition, durability in an environment such as outdoors where temperature and humidity are severe can be improved. Further, if the thickness of the undercoat is 300 nm or less, there is no risk of cracking or peeling of the antireflection film even after long-term use in the severe environment.

[0010]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing one embodiment, which is an antireflection film E1 of the synthetic resin optical component of this embodiment.
Is composed of an undercoat 2 deposited on the surface 1a of a plastic lens 1 made of polymethylmethacrylate (PMMA) and a multilayer film 3 which is a repeating multilayer film laminated on the undercoat 2. Silicon oxide SiO _x (2>x>), which has good adhesion to synthetic resin materials and excellent chemical resistance and wear resistance.
1) is a thin film made of a low refractive index material having a refractive index n = 1.49 to 1.59 as a main component and a film thickness d = 200 nm to 300 nm, and the multilayer film 3 is made of titanium oxide TiO ₂ or zirconium oxide ZrO _{2. 2} or a thin film of a first layer (hereinafter, referred to as “first layer”) 3a made of a high refractive index material containing a mixture of these as a main component, and a silicon oxide SiO _x (2 ≧).
x ≧ 1) as a main component, a second layer thin film (hereinafter referred to as “second layer”) 3b made of a low refractive index material, and titanium oxide TiO ₂ or zirconium oxide ZrO ₂ or a mixture thereof as a main component. And a third layer thin film (hereinafter referred to as “third layer”) 3c made of a high refractive index material and a low refractive index material containing silicon oxide SiO _x (2 ≧ x ≧ 1) as a main component. Thin film of the fourth layer (hereinafter referred to as "fourth layer") 3
It is constituted by d.

As a material for the undercoat 2, a refractive index n =
The reason why the low refractive index material containing silicon oxide as a main component of 1.49 to 1.59 is selected is polymethyl methacrylate (PMMA) or polycarbonate (PC), which is often used as a material for synthetic resin optical parts. The refractive index of polystyrene (PS) is within the above range, and the low refractive index material has excellent chemical resistance and abrasion resistance, and has good adhesion to the above synthetic resin. In addition, the amount of light scattering and the amount of light absorption when used as an undercoat are small.

The thickness of the undercoat 2 is 200n.
It has been proved by experiments that when it is m or less, sufficient chemical resistance and abrasion resistance cannot be obtained, and when it is 300 nm or more, cracks are likely to occur. In addition,
The first layer 3a and the second layer 3b of the multilayer film 3 constitute an equivalent thin film made of a high refractive index material and a low refractive index material, and the basic film configuration of the multilayer film 3 is the equivalent to the design wavelength λ. The thickness of the thin film is λ / 4, the thickness of the third layer 3c is λ / 4 or λ / 2, and the thickness of the fourth layer 3d is λ / 4. Further, the refractive index n and the optical film thickness nd of each of the layers 3a to 3d of the multilayer film 3 are preferably in the following ranges.

Refractive index n Optical thickness nd First layer 3a 1.95 to 2.15 0.05λ to 0.13λ Second layer 3b 1.43 to 1.55 0.03λ to 0.07λ Third layer 3c 1.95 to 2.15 0.21λ to 0.49λ Fourth layer 3d 1.43 to 1.55 0.20λ to 0.28λ Here, fundamental wavelength λ = 500 nm Next, the manufacturing process of this example will be described. explain.

First, polymethylmethacrylate (PMM
The plastic lens 1 of A) is carried into a known vacuum vapor deposition chamber, the vacuum vapor deposition chamber is evacuated to a high vacuum of 3 × 10 ⁻⁵ torr or more, and then O ₂ gas is introduced to the vacuum vapor deposition chamber. Set the pressure to 1.0 × 10 ⁻⁴ torr. Next, a silicon oxide S is formed by a resistance heating method or an electron beam heating method.
The evaporation material containing iO _x (2>x> 1) as a main component is heated and evaporated to form an optical film thickness n on the surface 1 a of the plastic lens 1.
The undercoat 2 with d = 330 nm is formed. The vapor deposition rate at this time was 10Å / sec. Then, the amount of O ₂ gas introduced is controlled to adjust the pressure in the vacuum deposition chamber to 5 × 10 ⁻⁵ to
The first layer 3a of the multilayer film 3 having an optical film thickness nd = 36 nm at a vapor deposition rate of 5Å / sec by evaporating an evaporation material containing a mixture of ZrO ₂ and TiO ₂ as a main component by heating with an electron beam heating method. To form. Further, the amount of O ₂ gas introduced is controlled to control the pressure in the vacuum deposition chamber to 1.0 × 10 ⁻⁴ to
rr is set, and the evaporation material containing SiO ₂ as the main component is heated and evaporated by the electron beam heating method, and the evaporation rate is 10Å /
The second layer 3b having an optical film thickness nd = 24 nm is formed in sec, then the amount of O ₂ gas introduced is controlled to set the pressure in the vacuum deposition chamber to 5 × 10 ⁻⁵ torr, and ZrO ₂ and TiO ₂ are added.
Mixture evaporated material mainly vaporized by heating by an electron beam heating method, an optical film thickness nd = 210 nm of the third layer 3c is formed at a deposition rate of 5 Å / sec, further, O ₂
Control the amount of gas introduced and set the pressure in the vacuum deposition chamber to 1.0 x 10
^-4 torr, the evaporation material mainly composed of SiO ₂ is heated and evaporated by the electron beam heating method, and the evaporation rate is 1
Fourth layer 3d having an optical film thickness nd = 115 nm at 0Å / sec
After forming the, by stopping the introduction of O ₂ gas pressurized to atmospheric pressure upon the pressure was reduced to once 3 × 10 ^-5 torr or more high vacuum pressure in the vacuum deposition chamber, opening the vacuum deposition chamber Product Take out.

The antireflection film E1 thus manufactured
Table 1 shows the material constitution, the refractive index n, the film thickness d and the optical film thickness nd of each thin film, and FIG. 2 shows the antireflection property thereof.

[0017]

[Table 1] Next, part of the manufacturing process and part of the material of the antireflection film or the plastic lens were changed to manufacture the antireflection films E2 to E4 of the first to third modifications. In the manufacturing process of the antireflection film E2 of the first modified example, the pressure of the O ₂ gas atmosphere in the vacuum deposition chamber at the time of depositing the undercoat is set to 1.5 × 10 ⁻⁴ torr, and the second layer of the multilayer film is formed. The fourth layer is formed by heating and evaporating a low-refractive index material containing SiO _x (2 ≧ x ≧ 1) as a main component by a known resistance heating method or electron beam heating method to keep the pressure of the O ₂ gas atmosphere in the vacuum deposition chamber under. Same as when depositing coat 1.5 × 10 ^-4 torr
For the first and third layers of the multilayer film, a high refractive index material containing TiO ₂ as a main component was heated and evaporated by a known resistance heating method or electron beam heating method. Since the other points are the same as the manufacturing process of the antireflection film E1 of the present embodiment, description thereof will be omitted.

In the manufacturing process of the antireflection film E3 of the second modification, the pressure of the O ₂ gas atmosphere in the vacuum deposition chamber when depositing the first layer and the third layer of the multilayer film is 1 × 10 ⁻⁴ torr.
The deposition rate was 2 to 3Å / sec. Other points are the same as the manufacturing process of the antireflection film E1 of the present embodiment.

The antireflection film E4 of the third modification is manufactured by using polycarbonate (PC) as the material of the plastic lens. The manufacturing process is the same as that of the antireflection film E1 of this embodiment.

The first to third parts manufactured in this way
Tables 2 to 4 show the material configurations of the antireflection films E2 to E4, the refractive index n, the film thickness d, and the optical film thickness nd of each thin film, and their antireflection characteristics are shown in FIGS. As shown in FIG.

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4] For comparison, the thickness d of the undercoat is set to 180
The antireflection film E5 of the first comparative example is manufactured by the same manufacturing process as that of the antireflection film E1 of the present embodiment.
An antireflection film E6 of the second comparative example was manufactured by the same manufacturing process as that of the antireflection film E1 with the thickness d of the undercoat being 310 nm. Material composition of both, refractive index n of each thin film,
The film thickness d and the optical film thickness nd are shown in Tables 5 and 6, respectively.
The antireflection characteristics are shown in FIGS.

[0024]

[Table 5]

[0025]

[Table 6] Next, the antireflection films E1 to E6 and the above-mentioned JP-A-60
The antireflection film disclosed in Japanese Patent Application Laid-Open No. 98401 has been disclosed in Japanese Patent Laid-Open No.
The antireflection film of 0-25101 is referred to as Conventional Example 2 and the antireflection film of JP-A-3-16101 is referred to as Conventional Example 3,
Table 7 shows the result of a quality evaluation test for evaluating each quality.

[0026]

[Table 7] From Table 7, the antireflection film E1 of the present example and the antireflection films E2 to E4 of the modified examples thereof are all excellent in adhesion, abrasion resistance and chemical resistance. It can be seen that there is no possibility of significant damage even in an environment with severe humidity or an environment with severe temperature change. The antireflection film E5 of the first comparative example
It can be seen that since the undercoat film thickness is insufficient, the chemical resistance is insufficient, and the antireflection film E6 of the second comparative example is prone to cracks because the undercoat film thickness is too large. Further, as described above, the conventional examples 1 and 3
It was found that the film of Example 2 had insufficient abrasion resistance and chemical resistance immediately after the film formation, and that the conventional example 2 had a difficulty in optical characteristics.

The following test methods evaluated (1) adhesion, (2) wear resistance, (3) chemical resistance, and (4) environment resistance in Table 7.

(1) Adhesion property A cellophane tape is attached to the surface of the antireflection film, the tape is instantly peeled in the direction perpendicular to the film surface, and the presence or absence of film peeling is visually observed. Only when the film peeling did not occur was evaluated as good.

(2) Abrasion resistance Silbon paper is rubbed on the surface of the antireflection film with a load of 300 g and rubbed back and forth 50 times, and visually inspected for scratches.
Only when there were no film scratches was considered good.

(3) Chemical resistance The surface of the antireflection film is rubbed with ethyl ether-soaked sillbon paper for 50 times with a load of 300 g and reciprocally rubbed, and the presence or absence of film floating or film scratches is visually observed. Only when the film was not lifted or scratched was considered good.

(4) Environmental resistance (4-1) Acceleration test at high temperature and high humidity A plastic lens having an antireflection film formed thereon was 70 ° C.-8.
After leaving for 500 hours in a thermostat set to 5% RH, the appearance of the film was visually observed, and only when no abnormality was observed, it was judged as good. Further, the above (1) adhesion,
Evaluation tests of (2) abrasion resistance and (3) chemical resistance were performed.

(4-2) Thermal shock test A plastic lens having an antireflection film formed thereon was -30 ° C /
After 10 cycles of 2 hours each at 60 ° C.-60% RH, the appearance of the film was visually observed, and only when no abnormality was observed, it was judged as good. Furthermore, the above-mentioned (1) adhesion, (2) abrasion resistance, and (3) chemical resistance evaluation tests were carried out.

[0033]

Since the present invention is configured as described above, it has the following effects.

It has excellent wear resistance, chemical resistance and optical characteristics, and is exposed to severe temperature and humidity conditions such as outdoors.
Alternatively, it is possible to realize an antireflection film of a synthetic resin optical component that is free from the possibility of deterioration of the above-mentioned characteristics, cracking, and film peeling even when used for a long time in an environment where the temperature and humidity greatly change. As a result, it is possible to realize an optical component made of synthetic resin, which has excellent durability outdoors and has little reflection.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example.

FIG. 2 is a graph showing antireflection characteristics of the antireflection film of FIG.

FIG. 3 is a graph showing antireflection characteristics of an antireflection film of a first modified example.

FIG. 4 is a graph showing antireflection characteristics of an antireflection film of a second modified example.

FIG. 5 is a graph showing antireflection characteristics of an antireflection film of a third modified example.

FIG. 6 is a graph showing antireflection characteristics of the antireflection film of the first comparative example.

FIG. 7 is a graph showing antireflection characteristics of the antireflection film of the second comparative example.

[Explanation of symbols]

 1 Plastic Lens 2 Undercoat 3 Multilayer Film 3a 1st Layer 3b 2nd Layer 3c 3rd Layer 3d 4th Layer

Claims (4)

[Claims] 1. An undercoat having a film thickness of 200 nm to 300 nm containing silicon oxide SiO _x (2>x> 1) as a main component formed on the surface of a synthetic resin optical component, and an undercoat formed on the undercoat. An antireflection film for optical parts made of synthetic resin, which is formed of a repeated multilayer film having an antireflection property formed. 2. The synthetic resin according to claim 1, wherein the undercoat containing silicon oxide SiO _x (2>x> 1) as a main component has a refractive index of 1.49 to 1.59. Anti-reflection film for optical parts. 3. The repeating multilayer film comprises TiO ₂ or ZrO ₂
Alternatively, a thin film made of a high refractive index material containing a mixture of these as a main component and a thin film made of a low refractive index material containing a SiO _x (2 ≧ x ≧ 1) as a main component are alternately laminated. The antireflection film of the synthetic resin optical component according to claim 1. 4. The repeating multilayer film comprises four thin films, each of which has a refractive index and an optical film thickness set within the following ranges.
An antireflection film for the synthetic resin optical component described. 1.95 ≦ n ₁ ≦ 2.15 0.05λ ≦ n ₁ d
₁ ≦ 0.13λ 1.43 ≦ n ₂ ≦ 1.55 0.03λ ≦ n ₂ d
₂ ≤ 0.07λ 1.95 ≤ n ₃ ≤ 2.15 0.21 λ n ₃ d
₃ ≦ 0.49λ 1.43 ≦ n ₄ ≦ 1.55 0.20 λ ≦ n ₄ d
₄ ≦ 0.28λ where λ: design wavelength (500 nm) n ₁ : refractive index of thin film of first layer n ₂ : refractive index of thin film of second layer n ₃ : refractive index of thin film of third layer n ₄ : Refractive index of fourth layer thin film n ₁ d ₁ : optical thickness of first layer thin film n ₂ d ₂ : optical thickness of second layer thin film n ₃ d ₃ : optical thickness of third layer thin film n ₄ d ₄ : Optical thickness of the thin film of the fourth layer However, the thin films of the first to fourth layers were formed in order from the thin film closer to the surface of the synthetic resin optical component.