JPH01229202A - Multi-layered reflection mirror - Google Patents

Abstract

PURPOSE:To obtain the multi-layered reflection mirror which has superior heat resistance and moisture resistance by providing such film density characteristics that the film density of a thin film of zinc sulfide is >=0.96 and the film density of a thin film of magnesium fluoride is >=0.98. CONSTITUTION:The reflection mirror 1 for a halogen lamp which is made of hard glass has a rotary parabolic recessed part 2 whose one surface is expanded, and the halogen lamp 3 is mounted in the center of the recessed part 2. A multi-layered film 4 adhered on the recessed part 2 consists of alternate 25 layers (lambda1-13=600nm, lambda14-25=450nm) of optical film thickness 1/4lambda of ZnS/ MgF2 constitution so that the film density of thin ZnS films is >=0.96 and the film density of the MgF2 films is >=0.98. Namely, when a high-refractive-index material of ZnS is denoted as H and a low-refractive-index material of MgF2 is denoted as L, those H and L are adhered six times each to form 12 layers and one layer of H is added to form 13 layers in total; and further the L and H are adhered six times each to form 12 layers in total, and those films are all formed by ion plating film formation.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a multilayer film reflector used for floodlights, etc., particularly a multilayer film reflector based on a cold light mirror and having excellent heat resistance and moisture resistance. .

[Conventional technology]

Conventionally, multilayer reflectors based on cold light mirrors have been widely used as light sources for store lighting, medical lighting, etc.; By doing so, the illuminated object is less likely to be heated by the heat rays, and the substrate is not heated when the heat rays pass through the multilayer film. This multilayer film reflector is made by alternately stacking thin films of high refractive index materials and thin films of low refractive index materials on the surface of a reflective substrate using a vacuum evaporation method. The larger the ratio, the higher the reflectance and the wider the reflection band. Generally, zinc sulfide (Zn8) and magnesium fluoride (MgF
2) Z n 8 / M g with thin films alternately laminated
Fz alternating layers or zinc sulfide and silicon oxide (8iO□)
The Zn8/8i0□ alternating layers are made by laminating thin films of
It is used as a multilayer film for reflective mirrors.

ZnS 7MgF2 alternating layers or ZnS/8
Table 1 shows the time required for the film to peel off when the lamp is turned on and when the mirror is left in a high temperature and humid atmosphere for the multilayer film reflector coated with alternating t O2 layers. The heat load due to lamp lighting is necessarily at 300°C and 350°C, and the high temperature and humidity atmosphere is when the reflecting mirror is left in an atmosphere with a temperature of 50°C and humidity of 90%.

Table 1 Z n 87M g F 2-thread layer film has good moisture resistance but poor heat resistance, so it is applied to light sources with relatively low heat load and long life, such as low output and long life halogen lamps. . Zn8/SiOz-based layered films have good heat resistance but poor moisture resistance, so they are applied to light sources with a high heat load and short life, such as high-output, short-life halogen lamps.

Further, when forming the above-mentioned multilayer film, a thin film formed by vacuum evaporation becomes a porous film due to the columnar growth of the film, resulting in a low S film density. Table 2 shows the confidentiality of each film forming material in the vacuum evaporation method.

Table 2 [Problems to be Solved by the Invention] Conventional multilayer film reflecting mirrors have drawbacks in either heat resistance or moisture resistance due to the low film density of the multilayer film. I had to select and use the appropriate one. However, as light sources have become higher in output and have a longer lifespan, it has become necessary to enhance the heat resistance and moisture resistance of multilayer films.

The present invention was made in consideration of the above circumstances, and
The object of the present invention is to provide a multilayer film reflecting mirror with excellent heat resistance and moisture resistance by increasing the film density of a MgF2-based multilayer film.

[Means to solve the problem]

In order to achieve the above object, the present invention forms a multilayer film having a film density at a high level of p1 by ionizing a vapor deposition material gas and depositing it on a substrate by an ion blating method. That is, in a multilayer reflector formed by alternately laminating a thin film of zinc sulfide and a thin film of magnesium fluoride on a reflective substrate surface, the film density of the thin film of zinc sulfide is 0.96 or more,
This is a multilayer film reflecting mirror having a secrecy characteristic in which the film density of a thin film of magnesium fluoride is 0.98 or more.

[For production]

Since the multilayer film reflector of the present invention has a multilayer film formed by the ion blating method, the film thickness is larger than that of the conventional multilayer film formed by vacuum evaporation, and the heat resistance and moisture resistance are greatly improved. can be done. Regarding the influence of the secrecy density of zinc sulfide and magnesium fluoride on the heat resistance and moisture resistance of multilayer films, we investigated the effect of the secrecy density t on multilayer film reflectors with different secrecy densities (t) when the lamp was turned on and when they were left in a bulky, hot and humid atmosphere. Table 3 shows the time required for film peeling to occur.

In the table, the atmosphere of the high temperature multi-channel is 50° C. and 90% humidity.

Table 3 As is clear from Table 3, the larger the flm film @ degree of zinc sulfide and magnesium fluoride, the better the heat resistance and moisture resistance, and the film density characteristics of the multilayer film reflector of the present invention.
That is, when the secrecy density of zinc sulfide becomes 0.96 or more and the secrecy density of magnesium fluoride becomes 0.98 or more, the heat resistance and moisture resistance reach almost the maximum value and become stable.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

A reflection for a halogen lamp (11 is made of hard glass) forms a paraboloid-shaped recess 5 (2) with its face expanded, and a halogen lamp (3) located in the center of the four parts (2). ) is attached. I!!lI9. (The multilayer film (4) deposited on 21 is Z n 8 / M g
Alternating layers with an optical thickness of 1/4λ consisting of 25 layers of P2 configuration (
λ1-13 = 6001m.

λ14-25 = 450 nm). That is, if the high refractive index material made of ZnS is the same and the low refractive index material made of MgF2 is (L), this (c) and C
(L) alternately 6 times for a total of 12 layers, and then (5) 1 time.
Layers were added to make a total of 13 layers, and (L) and (B) were further laminated and coated 6 times in total for a total of 12 layers. All of these coatings are formed by ion blasting.

The film forming conditions for the multi-rw expansion described above are as follows: a vacuum pressure of 8 x 10"" ~ I x 10") with argon gas introduced.
YV, AUG wave output 50W~10, DC bias 0~
1oKv1 substrate temperature 100-300°C, evaporation sources are resistance heating (Zn8) and electron beam (MgF2). Note that plasma cleaning is performed under the above conditions before film formation.

Table 4 shows the film density of the multilayer film and the time at which the film peels off when the lamp is turned on and when it is left in a high temperature and humid atmosphere for the multilayer film reflecting mirror configured as described above. The heat load due to lamp lighting is 300°C and 350°C, and the high temperature and humidity atmosphere is 50°C and 90% humidity.

Table 4 Note that the present invention is not limited to the above embodiments,
A similar effect can be obtained by depositing a multilayer film using the ion assist method. Further, a ZnS/8102-based multilayer film can also achieve the same effect as that of high exchange density.

〔Effect of the invention〕

The present invention is a multilayer film reflecting mirror configured as described above.
Since it has a high film density characteristic, it has much better heat resistance and moisture resistance than conventional ones, and is fully compatible with light sources such as high-output, long-life halogen lamps.

[Brief explanation of the drawing]

The drawings are cross-sectional views showing embodiments of the present invention.

Claims (1)

[Claims] In a multilayer reflector formed by alternately laminating zinc sulfide thin films and magnesium fluoride thin films on a reflective substrate surface, the film density of the zinc sulfide thin film is 0.96 or more, and the film density of the magnesium fluoride thin film is 0.96 or more. A multilayer film reflecting mirror having a film density characteristic of 0.98 or more.