JPH02230101A - Antireflection film for optical parts made of synthetic resin - Google Patents

Abstract

PURPOSE:To obtain a antireflection film having a low spectral reflectivity and good adhesive property and durability by forming vapor deposited films of a 4-layered structure having specific components on the surface of the optical parts made of a synthetic resin. CONSTITUTION:An SiOx (1<x<2) film having the good adhesive property is formed as a 1st layer to 50nm to 1mum thickness on the surface of the optical parts made of the synthetic resin. A 2nd layer 3 is formed of CeO2 to lambda/4 film thickness. Gaseous O2 is introduced to adjust the refractive index to 1.6 and a 3rd layer 4 is formed to 5 to 20nm film thickness at the time of the vapor deposition of an SiOy (1<y<2) film for this layer. A 4th layer 5 is formed of an Al2O3 film and is formed in such a manner that the film thickness obtd. after the thicknesses of the 3rd layer 4 and the 4th layer 5 are added attains lambda/4. The CeO2 film and the Al2O3 film are irradiated with oxygen ions by an ion assist method to have the better adhesive property and durability. As a result, the antireflection film having <=0.5 spectral reflectivity within lambda+ or -20nm range of central wavelength is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an antireflection coating for synthetic resin optical components used in optical systems that apply laser light, such as optical measurement and optical communication.

[Conventional technology]

Conventional antireflection coatings for synthetic resin optical components have a three-layer structure, with the first layer being SIOx and the second intermediate layer being C.I.O.x at a predetermined ratio. Mixture of 02 and S102, 3rd layer b”
8+Oy color rx ツ"C"), wavelength λ=780
It is known that the spectral reflectance is 0.5% or less at ~82 onm (for example, Japanese Patent Application Laid-Open No. 62-13460
No. 1.

[Problem to be solved by the invention]

However, the second layer, which is a vapor-deposited film made of a mixture of Ce02 and S+Oz, is unstable during vapor deposition because the melting points of each component are different, and the optical properties are unstable due to variations in refractive index power. Furthermore, since the third layer in contact with the air layer is made of SiO, it is not chemically stable and has a rather low surface hardness. The purpose of the present invention is to obtain a center wavelength λ0±2
The object of the present invention is to provide a stable antireflection coating for synthetic resin optical components that has a reflectance of 0.5% or less at 0 nm.

[Failure to solve the problem]

According to the present invention, from the surface side of the synthetic resin optical component, the first layer is SiOX (1<X<2), the second layer is C@02, and the third layer is S+Oy (1<)'<2. )
, the fourth layer is a vapor deposited film with a four-layer structure consisting of A4zQ3, and the third layer's S+Oy has approximately the same refractive index as the fourth layer's AlO3, and the thickness of the third layer is 5. ~2Qnm
This is achieved by forming an anti-reflection film with a

〔Example〕

Examples will be described with reference to the drawings.

FIG. 1 shows the structure of the antireflection coating of the synthetic resin optical component of the present invention. In Fig. 1K, PMMA is used as the synthetic resin substrate 10, and the first layer of 2 is St with good adhesion.
O. PM by introducing oxygen gas during vapor deposition.
The film is controlled to have a refractive index similar to that of the MA substrate, and is formed to have a film thickness of 5 Q nm to 1 μm. This film does not contribute to optical properties. The second layer of No. 3 is formed of Ce 0 2 as an antireflection film to have a thickness of λ/4.

Next, the third layer of No. 4 is an S + O y film, and the refractive index is adjusted to approximately 1.6 by introducing and controlling O2 gas during vapor deposition, and the film is formed to have a thickness of 5 to 200 m. The fourth layer of No. 4 is an AlzO3 film, and the combined thickness of the third and fourth layers is λ/
4 and f. Here CeO2 and A A!
The film of No. 203 was irradiated with oxygen ion gas using an ion assist method to form a film with good adhesion and durability. Next, the results of the environmental resistance test are shown.

1. Cracking resistance and peeling resistance test No cracks were observed after being left at 60°C, 90°C RH for 50 hours. Tape peeling test (Cellotape is peeled off instantly after adhesion. Repeated 20 times. No film peeling occurred.

2. Abrasion resistance test The lens paper was reciprocated 25 times under a load of 1 kg in dry and wet methods (lens paper soaked in ether alcohol), and no scratches were observed.

As described above, an antireflection film with good adhesion and durability was obtained.

Next, FIG. 2 shows the spectral reflectance characteristics of the antireflection film obtained in this example. Reflectance at center wavelength 73Qnm is 0.0
The optical properties show a minimum value of 5% or less, and a reflectance of 0.5% or less in the wavelength range of 760 to 800 nm. Note that the synthetic resin material is not limited to PMMA, but also PC.
, ps, etc. [Effects of the Invention] As described above, in the present invention, the center wavelength λθ±200
An anti-reflection film for synthetic resin optical parts can be obtained with a spectral reflectance of 0.5 inches or less in the range of m and good adhesion and durability.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the structure of the present invention. FIG. 2 is a graph showing the spectral reflectance in this example. 1...Synthetic resin substrate 2...First layer (8+Ox
) 3... 2nd layer (0.02) 4... 3rd layer
Layer (Stay) 5...4th layer (A/203) 1st side 2nd time

Claims (1)

[Claims] 1. A vapor deposited film having a four-layer structure of a first layer, a second layer, a third layer, and a fourth layer is formed from the surface side to the air side on the surface of a synthetic resin optical component. The structure constitutes an antireflection film, wherein the first layer is made of SiO_x (1<x<2), and the second layer is made of SiO_x (1<x<2).
The layer is made of CeO_2, and the third layer is made of SiO_y(1
<y<2), and the fourth layer is made of Al_O_3. 2. The third layer SiO_y is the fourth layer Al_2O
An antireflection film for a synthetic resin optical component according to claim 1, having a refractive index substantially the same as that of _3 and a film thickness of 5 to 20 nm.