JPS63297548A - Optical protective film and production thereof - Google Patents

Abstract

PURPOSE:To protect the surface of an optical material and to prevent the reflection of light from the surface of the film by dry-coating the surface with a heat radiating thin film whose thickness corresponds to <=1/4 of the operative wavelength. CONSTITUTION:An optical material as a reflecting film or a transmitting film for laser is prepd. The surface of the optical material is dry-coated with a heat radiating substance to form a film whose thickness corresponds to <=1/4 of the operative wavelength. The surface of the optical material is protected and the reflection of light from the surface of the film is prevented.

Description

[Detailed description of the invention] (Technical field) The present invention relates to an optical protective film.

More specifically, this invention has an extremely thin film with strong adhesion.
The present invention also relates to an optical protective film for lasers, etc., which has excellent surface flatness and heat dissipation properties, and a method for manufacturing the same.

(Background technology) Conventionally, thin films for lasers such as CaF and MgF2,
For example, when irradiated with a high-power laser, damage such as lattice defects may occur on the surface, or cracks may occur due to the generated lattice defects, reducing the reflectance and transmittance of the laser thin film. Ta.

Also, Hou To&! When producing a protective film using a fluorine-based reactive gas or a fluorine-based reactive gas, conventionally, the W of these gases was
The surface of the protective film is damaged by the I-blow, making it impossible to obtain a protective film with a homogeneous and flat surface.It also requires a film thickness of several thousand amps or more, which adversely affects the optical properties. There was a problem that deterioration due to heat was significant.

(Purpose of the Invention) The present invention was made in view of the above circumstances, and aims to improve the drawbacks of conventional optical protective films for lasers due to irradiation with light or heat, and to provide an extremely thin film. Even though
Optical protective liquid with good optical properties and can significantly reduce damage and deterioration! The purpose is to provide a V manufacturing method.

(Disclosure of the Invention) In order to achieve the above object, the optical protective film of the present invention is characterized by comprising a heat dissipating thin film having a thickness of 174 or less of the operating wavelength, and protecting the surface of an optical material. .

Further, the method for manufacturing the optical protective film of the present invention is characterized in that, for example, the surface of the laser material is dry-coated with a heat dissipating material having a thickness of 174 nm or less of the operating laser wavelength.

The optical material that protects the surface of the optical protective film of this invention is not particularly limited, and includes, for example, a reflective film or a transparent film deposited on a substrate for laser, ultraviolet light, or other optical applications, or even the substrate itself. The zero-reflection film and transmission film included may be a single layer film or a multilayer film.

Examples of such optical materials include KCjJ? ?
Vacuum evaporation, sputtering,
Single-layer or multilayer optical film, L i N b O produced by methods such as ion blating, ion beam deposition, cluster ion beam deposition, etc.
Examples include nonlinear optical crystal materials having deliquescent properties such as 3.L iI O3.

As heat dissipating thin films that protect the surfaces of these optical materials, A I N and A, which are transparent and have high thermal conductivity, are used.
1203, B e O, S XO, S 102, B
It is preferable to use a material such as N. The iF made of such a material is preferably formed by dry coating in a gas phase, and deposition by a cluster ion beam method is particularly preferred.

The thickness of this protective film is an extremely thin film of 174 nm or less of the operating wavelength used, for example, about 100 to 200 A in the case of laser light. There is no need for a conventional film thickness of several 100 OA or more.

To further explain along the attached drawings, for example, the first
As illustrated in the figure, a multilayer thin film 2 and thin ff3 formed by vacuum evaporation, sputtering, ion blating, cluster ion beam deposition, etc. are disposed on a substrate 1 of a laser optical material such as KCjl or NaCj. An optical protective film 4 is formed on all or a part of the surface of the optical film by, for example, cluster ion beam deposition as described above.

In the case of the cluster ion beam method, by controlling the acceleration voltage during vapor deposition and the electron current for ionization, a thin film of metal, semiconductor, or recording material with strong adhesion and excellent surface flatness is produced, for example, in the number of tens to Even an ultra-ri film of several tens of OA can be easily produced.

By making the film thickness of Hikari i7han WA4 thinner than 1/4 wavelength, reflection on the surface of this protective film 4 is prevented,
Moreover, light absorption in the protective film 4 can be significantly reduced.

Such optical protection vi4 protects the substrate 1 and the multilayer structure l.
It can prevent lA2.3 from being exposed to the atmosphere, and KC
Not only can the deliquescence of j+ substrates, NaCj substrates, etc. be suppressed, but also the ultra-thin film realizes a protective film with good optical properties and strong adhesion that suppresses damage and deterioration. In particular, in this invention, the thermal conductivity is high,
Since the protective film is made of a material with excellent heat dissipation,
For example, it is possible to obtain a protective film that dissipates heat caused by laser beam irradiation, has excellent cooling effects and heat resistance properties, and improves the incident energy of laser beams.

Next, Examples will be shown and the optical protective film of the present invention will be explained in more detail.

Example 1 Copper (C) cluster ion beam-deposited on a glass substrate
u) As a thin protective film, 1506 Aj! Coated with Nl. The manufacturing conditions for obtaining the AJN/Cu laminate are T
s R, T, PN2 = 2x10'Torr.

Regarding the obtained protective film AJIH, all differences in reflectance before and after laser annealing were determined in the 2nd L! Even by annealing in air at 300°C for 15 minutes as shown in J.
Compared to non-annealed AJIN/Cu (a), the anti-resistance properties of annealed AfJN/Cu (b) are almost unchanged.
) Oxidative deterioration of the film surface is suppressed.

For comparison, when looking at a copper (Cu) film without an AIN protective film, the reflectance of the annealed film (d) is significantly lower than that of the non-annealed film (C).

Example 2 An Al2O3 protective film was fabricated on a S i (111) substrate using a cluster ion beam.

Aluminum (All
A41203 was fabricated by simultaneously performing the vapor deposition of 1) and simultaneously irradiating 02 ions using an attached microwave ion source.

FIG. 3 shows the characteristics of the obtained A1□03 film as a relationship between the incident energy of oxygen gas (O2) and the etching rate with hydrofluoric acid (HP).

In the case of Al2O3 protective film (111), T sx 100
℃, P N 2-w4 X 10-5 Torr.

For the neutral (a) of the All cluster, Ie
= 20011A, V, = 0.5 and V (b) has a high etching rate and is a stable protective film.

Note that Aj2o3v! was created using the so-called reactive cluster ion beam method using aluminum cluster ions in an oxygen (02) atmosphere. However, similar characteristics can be obtained.

(Effects of the Invention) According to the present invention, an optical protective film for lasers, etc., which has excellent optical properties, heat dissipation properties, etc., even with an extreme FJ film, can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the present invention. FIGS. 2 and 3 are characteristic diagrams of optical thin films for lasers shown as examples of the present invention. 1...Substrate, 2.3...Thin film, 4...Optical protective film. Agent Patent Attorney Toshio Nishizawa No. 1
Figure 2 Temporary length (nm)

Claims (3)

[Claims] (1) An optical protective film comprising a heat-dissipating thin film having a thickness of 1/4 or less of the operating wavelength and protecting the surface of an optical material. (2) The optical protective film according to claim (1), wherein the optical material is a reflective film or a transparent film for laser. (3) A method for producing an optical protective film, which comprises dry-coating the surface of an optical material with a heat-dissipating material having a thickness of 1/4 or less of the operating wavelength.