JPH0486704A - Production of metallic dichroic mirror - Google Patents

Abstract

PURPOSE:To easily form a stable heat ray absorbing film by depositing metal chromium by evaporation as the heat ray absorbing film on the surface of a base material consisting of a metal or ceramics to form the film and forming dichroic films thereon. CONSTITUTION:The metal chromium as the heat ray absorbing film 2 is deposited by vapor deposition on the base material 1 consisting of aluminum and further, multilayered reflecting films (dichroic films) 3 of IR transmissibility are formed on the heat ray absorbing film 2. The dichroic films 3 consist of the alternate layers of 10 to 30 layers which are deposited with a high-refractive index film 3-1 consisting of titanium dioxide film or zine sulfide as a 1st layer, is deposited with the low-refractive index film 3-2 consisting of silicon dioxide or magnesium fluoride as a 2nd layer and is thereafter deposited successively with the high-refractive index films and low-refractive index films 3-n. The stable heat ray absorbing film 2 having the high adhesive property is easily obtd. in this way.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a reflector for a lighting device.

[Prior Art] High-intensity lighting equipment that uses incandescent bulbs, halogen lamps, carbon arc lamps, etc. as a light source, such as studio floodlights and movie projectors, has a metal film coated with aluminum or the like, or a metal film coated with aluminum or the like. A reflector made of a metal plate such as stainless steel is often used. Since these mirrors also reflect well the infrared rays emitted from the light source, they have the disadvantage that they cause a significant temperature rise on the irradiated surface, giving the irradiated person unbearable thermal discomfort.

On the other hand, glass, which is widely used in store lighting equipment, is used as a base material, and its surface is coated with an infrared-transmissive multilayer reflective film (
A so-called cold mirror (cold ray) equipped with a dichroic film has the property of reflecting only visible light and transmitting infrared rays, so it does not raise the temperature of the irradiated surface like the metal reflector mentioned above. However, since it cannot be made lighter like metal ones, it is heavy and difficult to handle.
Moreover, there is no degree of freedom in shaping.

Furthermore, it is easily damaged and poses safety problems.

A metal dichroic mirror, in which a heat ray absorbing film is formed on a metal or ceramic base material and a dichroic film is formed thereon, has been proposed and commercialized as a device that combines the above-mentioned advantages. ing.

The key point in manufacturing the metal dichroic mirror is the heat ray absorbing film formed between the base material and the dichroic film, and there are various types of the film, formation method, degree of heat ray absorption rate, and durability. A mirror has been devised.

Therefore, in Table 1 below, the method of forming a heat ray absorbing film and the types of the film are specified, and the drawbacks thereof are also listed.

[Table 1 below: The representative examples above are only a few examples of formation, but each
It has advantages and disadvantages in terms of durability and heat ray absorption rate, and also has the disadvantage that the forming method is complicated.

In particular, the formation method shown in Table 1 (3) is a formation method by introducing oxygen, and the degree of oxidation is controlled by the amount of oxygen.

However, 1. It has the disadvantage that the degree of oxidation is not stable depending on the vacuum level reached inside the Pelger, the substrate temperature, etc., so the control method is complicated, and the progress of oxidation due to changes over time leads to a decrease in absorbency. phenomenon is caused.

For this reason, conventionally, a simple method and.

A method for forming a stable heat ray absorbing film has been desired.

[Problems to be Solved by the Invention] The present invention has been made in view of the above, and as a method for forming the heat ray absorbing film, the heat ray absorbing film is formed by an extremely simple method, and the film is The present invention aims to provide a metal dichroic mirror formed by coating.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a metal dichroic ink mirror according to the present invention includes vaporizing metallic chromium (Cr) as a heat ray absorbing film on the surface of a base material made of metal or ceramics. It is characterized by using different materials to form a jet black metallic chromium film, and then forming a dichroic film on top of it.

[Function] In the reflecting mirror according to the present invention, only visible rays of light emitted from the light source are reflected by the upper infrared-transmissive multilayer reflective film, and infrared rays (heat rays) are transmitted. Then, the transmitted heat rays are absorbed by the jet-black metallic chromium film of the base layer,
It is converted into thermal energy and transferred to the substrate. The transferred heat is diffused or radiated backward from the back surface of the substrate by conduction or radiation through the substrate.

[Example] Embodiments according to the present invention will be described below based on the drawings.

FIG. 1 is an explanatory diagram showing a laminated structure of a reflecting mirror according to the present invention.

In the figure, 1 is a base material made of aluminum (AQ), and metal chromium (C
r) is deposited by vapor deposition.

Furthermore, an infrared-transmissive multilayer reflective film (dichroic film) 3 is formed on the heat ray absorbing film.

The dichroic ink film has a titanium dioxide film (
A high refractive index film 3-1 of TiO2) or zinc sulfide (ZnS) is deposited, and silicon dioxide (SiO2) is deposited as the second layer.
z) Alternatively, a low refractive index film 3-2 of magnesium fluoride (MgF2) is deposited, and then a high refractive index film and a low refractive index film 3-n are sequentially laminated to form an alternating film of 10 to 3o layers. .

FIG. 2 is a characteristic diagram showing the spectral reflectance of this reflecting mirror.

As is clear from the figure, approximately 90% in almost the entire visible light range.
% or more, and in the infrared region with a wavelength of 780 nm or more, the reflectance is about 20% or less.

Next, a method for forming a metal dichroic mirror according to the present invention will be described.

The method for forming a heat ray absorbing film, which is a feature of the present invention, is as follows.

It is as follows.

When forming a metallic chromium film on a substrate using the conventional vacuum evaporation method, a conventional black oxide thin film (Table 1
), unlike the method using metallic chromium (Cr
) using the vapor deposition material.

It is characterized by heating and evaporating using an evaporation source such as an electron gun to form a jet black metallic chromium film on the base material.

At this time, by using an inert gas (argon gas, etc.) as the introduced gas, the evaporated particles of metallic chromium fly and adhere to the substrate without being oxidized, resulting in a stable film with extremely high adhesion. That's what you get.

The fine structure of this metallic chromium film is jet black and has a dense structure when observed with an optical microscope.

The thickness of the film is controlled depending on the heat ray absorption rate of the film, which is formed to such an extent that the surface of the base material is completely hidden (usually about 1,000 to 400 degrees).

A multilayer reflective film (dichroic film) that transmits infrared rays is formed directly on the surface of the heat ray absorbing film made of a jet-black metallic chromium film. This reflective film is the same as the dichroic film formed on the surface of a normal cold mirror.

That is, it is formed by laminating normally about 10 to 30 layers of two types: a high refractive index film such as T i O 2 or ZnS, and a low refractive index film such as SiO 2 or MgF 2 .

The thickness of each layer is such that the maximum reflectance is at wavelength 5°O-60.
0nm, optimally, it is obtained at a wavelength of about 550nm (2,.), and the reflectance in the infrared region of the entire reflector combined with the heat ray absorption film is about 2.
It is selected to be 0% or less. (The well-known relationship between the wavelength λ showing the maximum emissivity and the single layer thickness d is d=λ.

There is a relationship of /4. ) Next, experimental examples are shown in Table 2. Table 2 shows the durability test results of metal dichroic mirrors formed with heat ray absorbing films according to the present invention.

[See the blanks below] As described above, the metal dichroic mirror on which the heat ray absorbing film according to the present invention is formed has good spectral reflectance characteristics and durability.

In addition to the metallic chromium film according to the present invention, in addition to the films listed in Table 1 above, there are also films for absorbing infrared rays that have passed through the infrared-transmissive multilayer reflective film, as well as black paint films. However, the heat ray absorption rate and durability are insufficient, and it is difficult to laminate a dichroic film on top of it.

Furthermore, when using a vapor deposition method, the formation method is complicated and it is difficult to control the film thickness.

On the other hand, in the method of forming a metallic chromium film according to the present invention, the metallic chromium particles are deposited in an inert gas atmosphere, so that the metallic chromium particles adhere extremely firmly to the base material, forming a jet black metallic chromium film. It can be formed with durability comparable to that of conventional vapor deposition methods.

Also, in terms of controllability, the film thickness can be easily controlled.

[Effects of the Invention] As is clear from the above description, the manufacturing method according to the present invention can form a heat ray absorbing film for a metal dichroic mirror with a relatively simple configuration, and has good spectral reflectance characteristics. , and has advantages such as not only excellent durability but also easy manufacture and easy control of the thickness of the heat ray absorbing film.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of an embodiment according to the present invention, and Figure 2 is the same.
It is a figure showing the spectral reflectance characteristic of an example.

Claims (1)

[Claims] (1) Metal chromium is vacuum-deposited as a heat ray absorbing film on the surface of a base material made of metal or ceramics in an inert gas atmosphere, and a high refractive index film and a low refractive index film are further applied on the heat ray absorbing film. A method for manufacturing a metal dichroic mirror, characterized by forming an infrared-transmissive multilayer reflective film consisting of alternately laminated films.