JPS60131502A - Metallic total reflection mirror - Google Patents

Abstract

PURPOSE:To obtain a total reflection film superior in both of adhesion with a glass base and reflectance, especially suitable for a type fixed to the inside of a polarizing prism by attaching an interlayer having a specified thickness range thinner than conventional ones on one side of a glass base. CONSTITUTION:A thin film 12 of a metal, such as Cr, Ni, or W, is vapor-deposited on a washed glass base 11. A total reflection film 13 is formed on the film 12 by vapor deposition of Cu or the like, and then, a corrsion-resistance film 14 is vapor-deposited on the film 12. The use of the thin metal interlayer 12 permits adhesion between the glass base 11 and the total reflection film 13 to be greatly enhanced and the polarized light reflectance to be remarkably made higher than the case of using the film 13 alone, up to a degree as high as 97.8% of P-polarized light and 98.4% of S-polarized light.

Description

DETAILED DESCRIPTION OF THE INVENTION iai Technical Field of the Invention The present invention relates to a reflective film that totally reflects light in an optical switch or the like, and more particularly to a metal total reflective film built into a polarizing prism.

(bl Technology background) An optical switch that uses a Faraday rotator as one of its main components and uses polarized light to switch the transmission path is incorporated into an optical signal transmission circuit system as a non-mechanical optical switch with no curved parts. A component whose configuration example is shown in Fig. 1.
As shown in FIG. 1, there are two polarizing beams a1 and 2, a 45-degree Faraday rotator 3 made of a Alladay rotation material such as '/IG driven by an electromagnet (not shown), and a 1''/2' wavelength. The polarizing prisms 1 and 2 are made up of a plate 4, with a polarizing prism 1 and 2 on one side, a polarizing film 5, and a total reflection film 6 deposited on the other half. Closely attached to both sides of glass flat plate '7, 2 pieces ty3
= It is composed of square prisms 8' and 9. The aforementioned polarization separation film 5 has such a ray quality that if the light incident from the 45-degree direction returns as P-polarized light, it will pass through the beam, and if it is S-polarized light, it will be totally reflected. - It is assumed that the total reflection film 6 totally reflects all light, regardless of whether it is p-polarized light or s-polarized light. By combining the Fala inserted in the middle of -゛≠--by rotating the electric current flowing through the stone bag that drives the rotator to rotate the light passing through the Hookday rotator clockwise or counterclockwise. , 1Npu
Take a t-! ;! INpjT-2 color polarizing prism 1
0υTPIIT of the light incident on the polarizing prism 2
-1 or 0IITPOT-2.

The polarization separation film and total reflection film incorporated into the polarizing prism in such an optical switch are required to have as little light loss as possible.

(C) Conventional technology and problems As a total reflection film used for the above applications, a metal total reflection film is used in which copper, which has a high reflectance in the wavelength band used for optical communications, is vapor-deposited on the surface of a glass substrate. It is being However, the reflectance of conventional metal total reflection films for light incident at an angle of 45 degrees is less than 82% for P-polarized light and less than 90% for S-polarized light, and each of the Reflectance for polarized light: 97.8%, 98. ' This is an extremely low value compared to 4%.

The reason for this is that copper has poor adhesion to the glass substrate, so metals such as chromium, tungsten, and nickel, which are known as 9) J, are deposited as an intermediate layer between the copper and the glass substrate to improve adhesion. However, the reflectance of the copper layer is highly dependent on the thickness of the intermediate layer. However, conventional metal total reflection films have an intermediate layer of 50 Å or more in consideration of the stability of adhesion, and there is a problem that the originally high reflectance cannot be effectively utilized due to consideration of the stability of adhesion. there were.

(dl Object of the Invention) An object of the present invention is to provide a metal total reflection film that has high adhesion between a glass substrate and a metal film and has a high reflectance.

(el) The structure and purpose of the invention is to increase the thickness of the intermediate layer formed between the glass substrate and the metal film by 5250 mm in a metal total reflection film formed by coating a metal film on one side of a glass substrate. I have achieved this by being a person.

in Examples of the invention The present invention will be explained in detail below with reference to the accompanying drawings.

FIG. 2 is a sectional view showing one embodiment of the present invention, in which 11 represents a glass substrate, 12 represents an intermediate layer, 13 represents a metal reflective film, and 14 represents a protective film.

First, various intermediate layers 12 are formed on a cleaned glass substrate 11 by depositing a chromium layer with varying thickness in a range of 5 to 100 layers. Subsequently, after copper is vapor-deposited as a metal 4 11113, a protective film 14 is applied to the metal reflective film 13 to prevent corrosion.
The metal is completely immersed and a spray film is obtained. .

Figure 3 shows the reflectance measured when the metal total reflection film having various intermediate layers 12 thus obtained was irradiated with a laser beam with a wavelength of 1.3μ from an angle of 45 degrees, and the thickness of the intermediate layer was measured. According to Figure 3, the reflectance is 9 for P-polarized light when the thickness of the chromium layer is 10.
4.8%, 97.2% for S-polarized light, and reflectance of 97.8% and 98.4 for each polarized light in case of copper single layer.
%.

On the other hand, regarding adhesion, a peel test was conducted on the metal total reflection films having various intermediate layers 12 obtained in the above-mentioned examples after adhering an adhesive tape to the metal reflection film 13. It was confirmed that if 5 layers were attached, the adhesion between the glass substrate and the metal film would be greatly improved, and if 10 layers were attached, it would be sufficient for practical use.

(Effects of the Invention 1) As described above, according to the present invention, it is possible to provide a metal total reflection film with high adhesion between a glass substrate and a metal film and a high reflectance.

[Brief explanation of the drawing]

Figure 1 shows an example of the configuration of an optical switch, Figure 2 is a sectional view showing an embodiment of the present invention, and Figure 3 shows the relationship between the thickness of the chromium layer and the reflectance of the metal reflective film using actual measurements. I'll do it with a diagram. In the figure, 11 represents a glass substrate, 12 represents an intermediate layer, 13 represents a gold reflective film, and 14 represents a protective film. 1 Figure 1 Army Figure 3 Figure 06010゜c, film thickness <A)

Claims (1)

[Claims] 1) In a metal total reflection film formed by coating a metal film on one side of a glass substrate, the thickness of the intermediate layer formed between the glass substrate and the metal film is 5 to 50 mm. A metal total reflection film that is unique in that it interacts with humans. 2. A metal total reflection film according to claim 1, characterized in that a protective film for preventing corrosion is provided on the metal film.