JPH09197101A - Antireflection film of plastic optical parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an antireflection film having high light transmissivity in a near IR region as well as in a visible light region. SOLUTION: A TiO2 film having an optical thickness of 47.5nm±5%, an SiO2 film having an optical thickness of 40nm±10%, a TiO2 film having an optical thickness of 195nm±5%, an SiO2 film having an optical thickness of 16.5nm±55% and a TiO2 film having an optical thickness of 80nm±5% and an SiO2 film having an optical thickness of 149nm±5% are successively formed on the surface of each of plastic optical parts to form the objective antireflection film. Since the number of films is increased and the thickness of each of the films is made optimum, transmissivity in a near IR region is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film provided on the surface of an optical component made of plastic, and more particularly to an antireflection film having a high transmittance in the visible light and near infrared light regions.

[0002]

2. Description of the Related Art Synthetic resins are frequently used as materials for optical parts such as lenses, mirrors and prisms.
Compared to glass optical parts, synthetic resin optical parts have the advantages of cost reduction, weight reduction, etc., and even optical parts with complicated shapes are easier to process than glass. Is.

Parts made of such a synthetic resin are inferior in abrasion resistance and scratch resistance as compared with glass and metal, so that a protective film or the like may be formed as a surface protection. Particularly when a synthetic resin is used as an optical component, an antireflection film is often provided in the same manner as in the case of optical glass in order to improve optical performance such as transmittance as well as the purpose of surface protection. In this case, the antireflection film is usually formed by a vacuum vapor deposition method for reasons such as high productivity.

In the case of forming such a film, in the case of optical glass, since the glass substrate can be heated to deposit the optical thin film, the adhesion between the glass substrate and the optical thin film is high, and the scratch resistance of the optical thin film itself is high. Is also good. On the other hand, in the case of synthetic resin, the heat resistance is low, so that the substrate cannot be heated. Therefore, for synthetic resin substrates,
There is a problem that the adhesion of the optical thin film and the scratch resistance of the optical thin film itself are significantly deteriorated.

In order to solve such problems, many proposals have hitherto been made. In the case of an antireflection film as an optical thin film, there is an antireflection film as disclosed in Japanese Patent Publication No. 6-87081. This antireflection film forms a mixture layer of silicon monoxide and zirconium oxide having an optical film thickness of λ / 4 (λ = 550 nm) on the surface of a plastic optical component, and the optical film thickness is formed thereon. λ /
No. 2 zirconium oxide layer is formed, and a silicon dioxide layer having an optical film thickness of λ / 4 is further formed thereon. This antireflection film is 400-88
It has a characteristic that the reflectance is approximately 2% or less in the wavelength region of 0 nm.

[0006]

By the way, in recent years, with the progress of computerization of optical instruments, the frequency of use of the above-mentioned optical element having an antireflection film in an optical system using an image pickup device such as a CCD is increasing. It was In this case, CC
Since D has better sensitivity in the near infrared region of about 1 μm than in the visible region, there is an increasing need for an optical element having good transmittance characteristics not only in the visible region of 400 to 700 nm but also in the near infrared region. Devices that require high sensitivity in the near-infrared region are not limited to CCDs, but other image pickup devices that use Si, solar cell panels that also use Si as a substrate, and the like.

However, in the conventional plastic optical component having the antireflection film, the reflectance in the near infrared region is high, and therefore, the light having the wavelength in the near infrared region is effectively transmitted to the image pickup device or the solar cell panel. There was a problem that I could not do.

The present invention has been made in consideration of the above problems, and is directed to a plastic optical component having a high transmittance, that is, a low reflectance, not only in the visible region but also in the near infrared region around 1 μm. It is intended to provide an antireflection film.

[0009]

In order to achieve the above object, in an antireflection film in which a thin film of 6 layers or 8 layers is formed on the surface of a plastic optical component, a first layer is formed in order from the surface to the air side. Is a titanium oxide, the second layer is made of silicon oxide, and the third and subsequent layers are alternately formed. An antireflection film for a plastic optical component, comprising: The anti-reflection film is formed on the surface of the plastic optical component by T with an optical film thickness of 47.5 nm ± 5%.
SiO ₂ film with an optical film thickness of 40 nm ± 10%
₂ film, an optical film thickness of 195 nm ± 5% of TiO ₂ film, an optical film thickness of 16.5 nm ± 5% of the SiO ₂ film, an optical film thickness of 80 nm ± 5% of TiO ₂ film, an optical film 149 thick
A SiO ₂ film of nm ± 5% is sequentially laminated from the surface side to the air side.

In this structure, the number of layers is 6 as compared with the conventional antireflection film on the surface of the plastic optical component of about 3 layers.
By increasing the number of layers and further optimizing the film thickness of each layer, it is possible to extend the antireflection band not only to the visible region but also to the near infrared region.

The antireflection film of the invention of claim 2 has an optical film thickness of 24 nm ± 5% on the surface of the plastic optical component.
TiO ₂ film, SiO with an optical film thickness of 78 nm ± 10%
₂ film, an optical film thickness of 75 nm ± 5% of TiO ₂ film, an optical film thickness of 34 nm ± 5% of the SiO ₂ film, an optical film thickness of 2
05 nm ± 5% TiO ₂ film, optical film thickness 24 nm ±
5% SiO ₂ film, Ti with optical film thickness of 80 nm ± 5%
O ₂ film, SiO ₂ film having an optical film thickness of 164 nm ± 5%,
Are sequentially laminated from the surface side to the air side.

In this structure, the number of layers is 8 as compared with the conventional antireflection film on the surface of the plastic optical component of about 3 layers.
By increasing the number of layers and further optimizing the film thickness of each layer, it is possible to dramatically widen the antireflection band not only in the visible region but also in the near infrared region.

The antireflection film of the invention of claim 3 has an optical film thickness of 26 nm ± 5% on the surface of the plastic optical component.
TiO ₂ film, SiO _{2 with} an optical film thickness of 74 nm ± 10%
₂ film, TiO ₂ film with an optical film thickness of 78 nm ± 5%, SiO ₂ film with an optical film thickness of 34 nm ± 5%, an optical film thickness of 2
06 nm ± 5% TiO ₂ film, optical film thickness 20 nm ±
5% SiO ₂ film, Ti with optical film thickness 90 nm ± 5%
O ₂ film, SiO ₂ film having an optical film thickness of 160 nm ± 5%,
Are sequentially laminated from the surface side to the air side.

In this structure, the number of layers is 8 as compared with the conventional antireflection film on the surface of the plastic optical component of about 3 layers.
By increasing the number of layers and optimizing the film thickness of each layer, the antireflection band is dramatically expanded not only to the visible region but also to the near infrared region. In this case, in particular, the reflectance in the visible light region can be selectively reduced. As a result, a higher power generation effect can be obtained particularly when used in a solar cell protection panel or the like, which has a higher conversion efficiency in the visible region than in the near infrared region.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 Injection-molded polycarbonate (PC) having a refractive index of 1.57 was used as a material for an optical element, and a 6-layer antireflection film was provided on the surface of this plastic optical component. This antireflection film is formed by placing an injection-molded optical component in a vacuum chamber and evacuating to 1 × 10 ⁻⁴ Pa,
With respect to the surface of this optical component, from the surface side toward the air side, TiO ₂ , SiO ₂ , TiO ₂ , SiO ₂ ,
The optical film thickness is 49.4 in the order of TiO ₂ and SiO _2.
nm, 36.9 nm, 195.3 nm, 17.3 nm,
It was performed by forming a film with a thickness of 78.9 nm and 151.1 nm. This film formation is performed by the electron beam evaporation method.

FIG. 1 shows the results of measurement of the spectral reflectance characteristics of the antireflection film thus produced at 300 to 1200 nm for vertically incident light. As shown in the figure, 40
The reflectance was 2% or less over a wide wavelength range of 0 to 950 nm, which was a good characteristic.

The optical element was allowed to stand at -40 ° C for 1 hour under the condition of 95% humidity, and then at 80 ° C for 30 minutes.
For 1 hour, then for another 30 minutes at -40 ° C
As a result, a heat cycle test in which a cycle of leaving for 1 hour was repeated was continuously performed for 3 days. After doing this test,
When the appearance of the antireflection film was observed with an optical microscope, no changes such as cracks were found. After this test, the spectral reflectance characteristics at 300 to 1200 nm were similarly measured. No change was observed in the characteristics before and after the test, and the reflectance was 2% or less over the wide wavelength range of 400 to 950 nm. It maintained good characteristics.

(Second Embodiment) Injection-molded polymethylmethacrylate (PMMA) having a refractive index of 1.49 is used as a material for an optical element, and a 6-layer antireflection film is provided on the surface of this plastic optical component. . For the antireflection film, the molded optical component is put in a vacuum chamber, and TiO ₂ , SiO ₂ , TiO ₂ , SiO ₂ and TiO ₂ are formed as in the first embodiment.
₂ , SiO ₂ in this order with an optical film thickness of 45.6 nm,
43.7 nm, 193.9 nm, 16.0 nm, 80.
It was provided by forming a film with a thickness of 8 nm and 147.5 nm. 300 of the antireflection film thus produced
The results of measuring the spectral reflectance characteristics at ˜1200 nm are shown in FIG. As shown in the figure, the reflectivity is 2% or less over a wide wavelength range of 400 to 950 nm, which is a good characteristic.

Further, as in the first embodiment, this optical element is used under the conditions of a temperature of -40 to 80 ° C. and a humidity of 95%.
A heat cycle test was repeated for a day, but no change was observed in the appearance and properties of the antireflection film.

(Third Embodiment) Injection-molded polymethylmethacrylate (PMMA) having a refractive index of 1.49 is used as a material for an optical element, and an eight-layer antireflection film is provided on the surface of this plastic optical component. . For the antireflection film, the optical element is placed in a vacuum chamber, and Ti
O ₂ , SiO ₂ , TiO ₂ , SiO ₂ , TiO ₂ , Si
O ₂ , TiO ₂ and SiO ₂ in this order have an optical film thickness of 2
3.8 nm, 83.1 nm, 75.1 nm, 33.9n
m, 206.7 nm, 24.9 nm 78.9 nm, 16
It was provided by forming a film with a thickness of 5.6 nm.

FIG. 3 shows the results of measuring the spectral reflectance characteristics of the antireflection film thus produced at 400 to 1200 nm. As shown in the figure, 410 to 1120 nm
Has a reflectance of 2% or less over a very wide wavelength range, and a reflectance of 1% in the wavelength range of 430 to 1050 nm.
The following characteristics are good.

Further, this optical element is used under the conditions of a temperature of -40 to 80 ° C. and a humidity of 95% as in the first embodiment.
A heat cycle test was repeated for a day, but no change was observed in the appearance and properties of the antireflection film.

(Embodiment 4) Injection-molded polycarbonate (PC) having a refractive index of 1.57 was used as a material for optical elements, and an 8-layer antireflection film was provided on the surface of this plastic optical component. That is, this optical element was placed in a vacuum chamber, and TiO ₂ , Si
O ₂ , TiO ₂ , SiO ₂ , TiO ₂ , SiO ₂ , Ti
O ₂ and SiO ₂ in this order have an optical film thickness of 24.2 n
m, 72.9 nm, 75.6 nm, 34.5 nm, 20
4.4 nm, 23.0 nm, 81.3 nm, 163.5
The film is formed to a thickness of nm.

FIG. 4 shows the result of measurement of the spectral reflectance characteristic of the vertically incident light of the antireflection film thus produced at 400 to 1200 nm. As shown in FIG.
2% reflectance over a very wide wavelength range of 1070 nm
In the wavelength region of 430 to 1000 nm, the reflectance is 1% or less, which is a good characteristic.

Further, this optical element is used under the conditions of a temperature of -40 to 80 ° C. and a humidity of 95% as in the first embodiment.
A heat cycle test was repeated for a day, but no change was observed in the appearance and properties of the antireflection film.

(Embodiment 5) Injection-molded refractive index
Light 1.49 polymethylmethacrylate (PMMA)
This plastic optical component used as a material for scientific elements
8 layers of antireflection film were provided on the surface of the. Anti-reflection film is optical
The element was placed in a vacuum chamber and TiO 2 was added as in the first embodiment._Two,
SiO_Two, TiO_Two, SiO_Two, TiO_Two, SiO_Two,
TiO_Two, SiO _TwoOptical thickness of 26.6
nm, 78.7 nm, 77.9 nm, 32.6 nm, 2
11.0 nm, 20.5 nm, 90.3 nm, 164.
It was provided by forming a film with a thickness of 1 nm.

40 of the antireflection film thus produced
The result of having measured the spectral reflectance characteristic at 0 to 1200 nm is shown in FIG. As shown in the figure, the reflectance is 2% or less in the entire wavelength range of 430 to 1120 nm, and 1% or less in the wavelength range of 480 to 760 nm, and particularly the average reflection at 500 to 700 nm. Rate is 0.52
%, Which is a good characteristic.

This optical element is used in the same manner as in the first embodiment.
A heat cycle test was repeated for 3 days under the conditions of a temperature of 40 to 80 ° C. and a humidity of 95%, but no change was observed in the appearance and properties of the antireflection film.

(Embodiment 6) Molded by extrusion
Made of amorphous polyolefin having a refractive index of 1.52
Used as a material for the surface of this plastic optical component
8 layers of antireflection film were provided. This antireflection film is an optical element
The child is placed in a vacuum chamber and TiO 2 is added as in the first embodiment._Two, S
iO_Two, TiO_Two, SiO_Two, TiO_Two, SiO_Two, T
iO_Two, SiO _TwoOptical thickness of 26.6n
m, 76.7 nm, 78.9 nm, 33.5 nm, 21
1.0 nm, 20.3 nm, 90.3 nm, 164.3
It was provided by forming a film with a thickness of nm.

40 of the antireflection film thus produced
The results of measuring the spectral reflectance characteristics at 0 to 1200 nm are shown in FIG. As shown in the same, 430 to 1100 nm
Has a reflectance of 2% or less over a very wide wavelength range, and is 1% or less in a wavelength range of 450 to 770 nm, and particularly has an average reflectance of 0.54% in a wavelength range of 500 to 700 nm. It has various characteristics.

Similar to the first embodiment, this optical element is
A heat cycle test was repeated for 3 days under the conditions of a temperature of 40 to 80 ° C. and a humidity of 95%, but no change was observed in the appearance and properties of the antireflection film.

(Embodiment 7) Injection-molded polycarbonate (PC) having a refractive index of 1.57 was used as a material for optical elements, and an 8-layer antireflection film was provided on the surface of this plastic optical component. In this antireflection film, the optical element is placed in a vacuum chamber, and TiO ₂ , Si is used as in the first embodiment.
O ₂ , TiO ₂ , SiO ₂ , TiO ₂ , SiO ₂ , Ti
Optical film thickness of 26.1n in the order of O ₂ and SiO ₂ respectively
m, 71.6 nm, 77.5 nm, 35.4 nm, 20
0.6 nm, 19.4 nm, 88.4 nm, 156.7
It was provided by forming a film with a thickness of nm.

40 of the antireflection film thus produced
FIG. 7 shows the result of measurement of the spectral reflectance characteristic at 0 to 1200 nm. As shown in the same, 420 ~ 1020nm
Has a reflectance of 2% or less over a very wide wavelength range, and is 1% or less in the wavelength range of 420 to 780 nm, and an average reflectance of 0.57% particularly in the wavelength range of 420 to 700 nm. It has various characteristics.

This optical element is used in the same manner as in the first embodiment.
A heat cycle test was repeated for 3 days under the conditions of a temperature of 40 to 80 ° C. and a humidity of 95%, but no change was observed in the appearance and properties of the antireflection film.

[0035]

According to the first aspect of the present invention, the number of layers is increased to 6 as compared with the conventional antireflection film on the surface of the plastic optical component of about 3 layers, and the film thickness of each layer is further increased. Since it has been optimized, it is possible to extend the antireflection band not only to the visible region but also to the near infrared region.

According to the second aspect of the present invention, the number of layers is increased to eight layers as compared with the conventional antireflection film on the surface of the plastic optical component of about three layers, and the film thickness of each layer is further optimized. As a result, the antireflection band can be dramatically expanded to the near infrared region as well as the visible region.

According to the third aspect of the present invention, the number of layers is increased to eight layers as compared with the conventional antireflection film on the surface of the plastic optical component of about three layers, and the film thickness of each layer is further optimized. It is possible to dramatically widen the antireflection band not only in the visible region but also in the near infrared region, and it is possible to selectively reduce the reflectance particularly in the visible light region. This makes it possible to obtain a higher power generation effect when used in a protective panel for solar cells or the like, which has a higher conversion efficiency in the visible region than in the near infrared region.

[Brief description of drawings]

FIG. 1 is a spectral reflectance characteristic diagram of an antireflection film according to a first embodiment.

FIG. 2 is a spectral reflectance characteristic diagram of the antireflection film of the second embodiment.

FIG. 3 is a spectral reflectance characteristic diagram of an antireflection film according to a third embodiment.

FIG. 4 is a spectral reflectance characteristic diagram of an antireflection film according to a fourth embodiment.

FIG. 5 is a spectral reflectance characteristic diagram of the antireflection film of the fifth embodiment.

FIG. 6 is a spectral reflectance characteristic diagram of the antireflection film of the sixth embodiment.

FIG. 7 is a spectral reflectance characteristic diagram of the antireflection film of the seventh embodiment.

Claims (3)

[Claims] To 1. A plastic optical component of the surface, an optical film thickness of 47.5 nm ± 5% of TiO ₂ film, an optical film thickness of 40 nm ± 10% of the SiO ₂ film, an optical film thickness of 195 nm ± 5% TiO ₂ film, optical film thickness 16.5 nm ± 5% SiO ₂ film, optical film thickness 80 nm ± 5% TiO ₂ film, optical film thickness 149 nm ± 5% SiO ₂ film , Are laminated in order from the surface side to the air side, and an antireflection film for a plastic optical component. 2. A TiO ₂ film having an optical film thickness of 24 nm ± 5%, a SiO ₂ film having an optical film thickness of 78 nm ± 10%, and an optical film thickness of 75 nm ± 5% on the surface of a plastic optical component. TiO ₂ film, optical film thickness 34 nm ± 5% SiO ₂ film, optical film thickness 205 nm ± 5% TiO ₂ film, optical film thickness 24 nm ± 5% SiO ₂ film, optical film thickness 80 nm ± 5% of TiO ₂ film, an optical film thickness of 164 nm ± 5% of the SiO ₂ film, but the plastic optical component antireflection film characterized by being laminated in this order from the surface side to the air side . To 3. A plastic optical component of the surface, an optical film thickness of 26 nm ± 5% of TiO ₂ film, an optical film thickness of 74 nm ± 10% of the SiO ₂ film, an optical film thickness of 78 nm ± 5% TiO ₂ film, optical film thickness of 34 nm ± 5% SiO ₂ film, optical film thickness of 206 nm ± 5% TiO ₂ film, optical film thickness of 20 nm ± 5% SiO ₂ film, optical film thickness 90 nm ± 5% of TiO ₂ film, an optical film thickness of 160 nm ± 5% of the SiO ₂ film, but the plastic optical component antireflection film characterized by being laminated in this order from the surface side to the air side .