JPH01155302A - Optical multilayered film of optical parts made of synthetic resin - Google Patents

Abstract

PURPOSE:To obtain optical multilayered films which have good adhesiveness to a synthetic resin substrate and are crack-free by forming a 1st layer on the substrate of SiO deposited at 3-5nm/sec vapor deposition rate, forming the even layers of the 2nd and subsequent layers of SiO2 and forming the odd layers of the 3rd and subsequent layers of CeO2. CONSTITUTION:The 1st layer on the front side of the optical multilayered films formed on the surface of the synthetic resin substrate 1 is formed of the SiO 2 formed at the vapor deposition rate set at 3-5nm/sec. The even layers of the 2nd and subsequent layers are formed of the SiO2 3 and the odd layers of the 3rd and subsequent layers are formed of the CeO2 4, by which the optical multilayered films of the synthetic resin parts are constituted. The optical multilayered layers function as multilayered reflecting films, antireflection layers, half mirrors, filters, etc. The excellent adhesiveness is thereby obtd. and the cracking is prevented without impairing the surface accuracy of the substrate; in addition, the durability is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical multilayer film for optical components made of synthetic resin.

[Conventional technology]

In recent years, in place of inorganic glass, synthetic resins, which have a greater degree of freedom in shape, are lightweight, and are inexpensive, have been increasingly used as materials for optical components such as lenses, mirrors, and prisms. Along with this, even more stringent conditions such as adhesion and heat resistance are required for the optical multilayer film of synthetic resin optical parts. Many anti-reflection films have been proposed, and conventionally, for example, optical multilayer films disclosed in Japanese Patent Publication No. 53-306, Japanese Patent Application Laid-open No. 56-121001, Japanese Patent Application Laid-Open No. 58-60701, etc. Are known.

Such conventional optical multilayer films for synthetic resin optical components form a SiO film as a first layer on the surface of a synthetic resin substrate to improve adhesion to the synthetic resin substrate, and (7) S
s i O, ALOi on the iO film.

A thin film of ZrOx, Tie, MgF, etc. is formed. This optical multilayer film has good adhesion to the substrate by using SiO for the first H in contact with the surface of the synthetic resin substrate.

On the other hand, ZrO□, TiO□, etc. have high melting points among the evaporation materials for the second layer and below to be formed on the SiO film, so they cannot be deposited using the same equipment setting method as when forming an optical multilayer film on a normal glass substrate. The evaporation substrate is heated under the influence of radiant heat from the evaporation source, which may deteriorate the surface precision, which is most important for optical components. As a countermeasure, methods have been considered to reduce the influence of radiant heat from the evaporation source by increasing the distance from the evaporation source to the substrate or by providing a shielding plate between the evaporation source and the substrate. However, both of the above methods inevitably require a long deposition time, which is undesirable from the viewpoint of productivity. Therefore, a low melting point substance is usually used as the vapor deposition material.

In addition, as mentioned above, the adhesion to the synthetic resin substrate can be solved by using SiO as the 11th layer, but when increasing the number of optical multilayer films, film stress and Due to the correlation between
We are trying to obtain good results in heat cycle tests.

[Problem that the invention seeks to solve]

However, in the optical part N film of the conventional synthetic resin base mentioned above, the tendency of the film stress in the SiO film formation state changes depending on the vapor deposition conditions of the first layer, SiO, and even if the film structure is the same, the vapor deposition conditions Depending on the difference in heat cycle test, some cranks occur and some don't.

The present invention has been made in view of these problems, and aims to provide an optical multilayer film for synthetic resin optical components that has good adhesion to the substrate and does not cause cracks, without impairing the surface precision of the substrate. purpose.

[Means and effects for solving the problems] In order to solve the above-mentioned conventional problems, the present invention provides the first layer on the surface side of the optical multilayer film formed on the surface of the synthetic resin substrate by reducing the deposition rate. An optical multilayer film of a synthetic resin optical component was constructed by using SiO formed at a rate of 3 to 5 rv/sec, the second and subsequent even-numbered layers being Sin, and the third and subsequent odd-numbered layers being CeO□.

Such an optical multilayer film is a multilayer reflective film 2 antireflection film.

It functions as a half mirror, filter, etc.

In the present invention, the deposition rate of the first layer is 3nwa/se.
The reason for choosing c is that if it is less than 3 nm/sec, cracks will occur in the heat cycle test and the adhesion with the substrate will deteriorate, and if it exceeds 5 nm/sec, there will be no evaporation source on the substrate. Splash (so-called flying, where the vapor deposition material adheres in the form of particles and causes film peeling) occurs, which is undesirable because it impairs the appearance quality, and there is also a lot of variation in controlling the film thickness. This is because it becomes difficult to obtain reproducibility of spectral characteristics.

In addition, when the film formation state was examined using an X-ray photoelectron analyzer (ESCA) when the deposition rate was less than 3 rv/see, it was found that the SiO component was lower than that of the film deposited at 3 to 5 nm/see, and the Si There were a lot of them. This indicates that Sigh was inferior to SiO in terms of adhesion and cracking to the synthetic resin substrate. Furthermore, the degree of vacuum during the first layer deposition was 6×10− to 9×10
-'Torr is preferred.

〔Example〕

(First Example) The optical multilayer film (multilayer antireflection l1l) of the synthetic resin optical component of this example is constructed as shown in FIG. 1 and Table 1.

Table 1 λ: 500 nm That is, the synthetic resin substrate l is made of PMMA, and the degree of vacuum before vapor deposition is 6 Xl0-'' to 8 Xl0-'Torr.
and the deposition rate is 3 to 5 n-/s without heating the substrate l.
A SiO film 2 is formed as a first N film on the surface of a synthetic resin substrate 1 by a resistance heating method while maintaining the temperature at EC. Also, 5iOtl of this 1st IW! A 5tot film 3 is formed on the even-numbered layers below the second layer on the second layer by an electron gun method, and the second layer of 5iO1l! A CeO film 4 is formed on odd-numbered layers of 3N and below on 2 by an electron gun method.

The optical multilayer film of this example has reflectance characteristics similar to those of ordinary optical glass products, as shown in FIG. 2.

In addition, heat cycle test (-30°C, 1 hour←→8
The optical multilayer film of this example had good adhesion and no cracks even after 10 repetitions of heating at 0°C for 1 hour).

(Second Example) The optical multilayer film (multilayer half mirror) of the synthetic resin optical component of this example is constructed as shown in FIG. 3 and Table 2.

Table 2 That is, the synthetic resin substrate 1 is made of PMMA, and the first
The layer is SiO film 2, and the even numbered layers below the second layer are SiO film 2.
O! lI3, CeotW14 for odd-numbered layers below the third layer
are formed under the same vapor deposition conditions as in the first embodiment.

The optical multilayer film of this example showed good results as shown in the reflectance characteristics shown in FIG. 4, and also had good adhesion and no cracks in the heat cycle test.

(Third Example) The optical multilayer film (multilayer half mirror) of the synthetic resin optical component of this example is constructed as shown in FIG. 5 and Table 3.

Table 3 λ: 500 nm That is, the synthetic resin substrate 1 is made of PMMA, and the first
SiO film 2 is used for N, and SiO□ is used for even-numbered layers below the second layer.
CeotMtr is formed in the film 3 and odd-numbered layers below the third layer under the same vapor deposition conditions as in the first embodiment.

As shown in the reflectance characteristics in FIG. 6, the optical multilayer film of this example had a reflectance of nearly 70% in the visible range at 45° incidence, and was a half mirror with little coloring. Also, in a heat cycle test, adhesion was good and no cracks were generated.

〔Effect of the invention〕

As described above, according to the optical multilayer film of the synthetic resin optical component of the present invention, the first layer on the synthetic resin substrate is formed of SiO at a vapor deposition rate of 3 to 5 nm/sec, and the second layer and Even-numbered layers are formed of Sin, and odd-numbered layers from the third layer onwards are formed of C.
Since it was formed with eO, without impairing the surface accuracy of the base,
It has excellent adhesion and can prevent cranking.
Improves durability. This expands the field of application of synthetic resin optical components and provides products with high added value.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the first example of the optical multilayer film of the synthetic resin optical component of the present invention, FIG. 2 is a reflectance characteristic diagram of the optical multilayer film obtained in the first example, and FIG. 4 is a longitudinal sectional view showing the second embodiment of the present invention, FIG. 4 is a reflectance characteristic diagram of the optical multilayer film obtained in the second embodiment, and FIG. 5 is a longitudinal sectional view showing the third embodiment of the present invention. , FIG. 6 is a reflectance characteristic diagram of the optical part KM obtained in the third example. 1...Synthetic resin substrate 2...Si○ film 3...Sin, film 4...CaO2 film Agent Patent attorney Takeshi Nara Figure 1 Figure 2 4oo soo soo 700 ,,,n) Wavelength Figure 3 Figure 4 4''' 31A1. 61#
! iTU tnm. Figure 5 Figure 6 Wavelength

Claims (1)

[Claims] (1) The first layer on the surface side of the optical multilayer film formed on the surface of a synthetic resin substrate is made of silicon monoxide formed at a vapor deposition rate of 3 to 5 nm/sec, and the even numbered layers from the second layer onwards are made of silicon dioxide. An optical multilayer film for a synthetic resin optical component, characterized in that the odd-numbered layers from the third layer onwards are made of cerium dioxide.