JP2787987B2 - Reflector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for manufacturing devices and measuring devices for laser applications, optical devices for optical communication and optical information processing, OA devices, optical devices such as cameras, and the like. Related to reflecting mirrors.

[Conventional technology]

In laser application equipment and optical application equipment, reflecting mirrors are often used as components of an optical system. Such reflecting mirrors include aluminum, silver, gold, and copper on the surface of a mirror-polished glass substrate or a metal substrate. , A reflective film made of a metal such as chromium, and a thin layer of silicon monoxide, magnesium fluoride, etc. as a protective film for providing mechanical and chemical durability, In order to have an improvement effect, a thin layer of zirconium dioxide, titanium dioxide, cerium dioxide, or the like is used as a single layer or in combination to provide a multilayer structure.

[Problems to be solved by the invention]

Such conventional mirrors are used by being incorporated in various devices, but since the surface is contaminated with dust, dirt, moisture, or chemicals, a cloth or paper for wiping is sometimes used. It needs to be cleaned with a cleaning solution. However, when such cleaning is performed, there is a defect that the reflection surface is easily scratched or peeled off, and there is also a problem that peeling or clouding occurs due to a change in temperature or humidity, resulting in poor durability.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a reflecting mirror which has excellent durability, can withstand cleaning, and has good optical characteristics.

[Means for solving the problem]

Such an object of the present invention, on the substrate surface of the optical element, a reflective layer comprising a metal layer or a metal layer and a dielectric material layer,
A surface protection layer composed of a mixture of silicon nitride and silicon dioxide can be attained by a reflecting mirror characterized by being sequentially laminated, and further comprising silicon carbide between the substrate surface and the reflection film layer By providing the lower layer, a more reliable reflecting mirror can be provided.

The base material for achieving the reflecting mirror of the present invention may be a glass substrate or a metal substrate whose surface is mirror-polished, or a synthetic resin. Although a reflective film layer may be provided directly on the surface of such a base material, a lower layer made of silicon carbide may be provided by, for example, a vacuum evaporation method,
It can be provided by a thin film forming method such as a sputtering method or an ion plating method. Due to the existence of such a lower layer made of silicon carbide, the durability of the reflective film layer is further improved. In this case, the thickness of the lower layer is preferably in the range of 400 to 600 °.

The metal constituting the reflective film layer of the reflector of the present invention may be a known metal conventionally used to form a reflective film, for example, aluminum, silver, gold, copper, chromium, or the like,
Such a metal layer can be formed by the same thin film forming method as the lower layer, and the thickness thereof is preferably in the range of 1,000 to 2,000 mm. The dielectric material layer also forming part of the reflection film layer may be a single layer of a thin layer of, for example, zirconium dioxide, titanium dioxide, cerium dioxide, silicon dioxide, magnesium fluoride, or the like, or zirconium dioxide, titanium dioxide. And a thin layer such as cerium dioxide and a thin layer such as silicon dioxide and magnesium fluoride. Such a dielectric material layer is formed by laminating on the metal layer by the same thin film forming method as described above.
Its thickness is preferably about 1/4 or 1/2 of the wavelength of the light used.

Further, the mixture of silicon nitride and silicon dioxide which is to be the surface protective layer of the reflector of the present invention is preferably a mixture of superior silicon nitride and inferior silicon dioxide. Mixtures with up to 10% of silicon dioxide are preferably used. Such a surface protective layer can be formed by the same thin film forming method as described above, but its thickness is preferably about 1/4 or 1/2 of the wavelength of the light used.

[Operation] The reflecting mirror of the present invention does not cause peeling or corrosion of the reflecting film even under high humidity, and scratches are generated even when rubbed with a cloth or paper containing a cleaning liquid such as a solvent. There is no fear.

[Example 1] A substrate made of float glass (FL-5) was washed sufficiently and dried sufficiently, and then attached to a holder and set in a vacuum deposition apparatus. The substrate temperature was 180 ° C and the degree of vacuum was 1 × 10 ^-5. ~ 3 × 10
Aluminum deposited under ^-5 Torr film forming conditions, thickness 1500Å
Was formed.

Next, using a target of a mixture of silicon nitride and silicon dioxide in a weight ratio of 85:15, the substrate temperature was set to 180 ° C., and the film was deposited on the reflective film layer by electron beam heating, and the optical film thickness was adjusted to the wavelength used. A surface protective layer corresponding to 1/4 was formed.

The sectional configuration of the reflector A thus obtained is as shown in FIG. Here, 1 is a substrate, 3 is a reflective film layer, and 4 is a surface protective layer.

This reflector A was subjected to a moisture resistance test for 72 hours in an atmosphere of 50 ° C. and 90% RH, but no change was observed.
A cleaning test was conducted by rubbing with a cloth containing a mixed cleaning solution of ethanol and ether, but no scratches or peeling occurred.

 FIG. 3 shows the optical characteristics of the reflecting mirror A.

Example 2 Using a substrate similar to that of Example 1, a reflective film layer of aluminum having a thickness of 1200 ° was first formed by the same method as that of Example 1. Next, the temperature of the substrate was set to 270 ° C., and a magnesium fluoride film having an optical thickness corresponding to / 4 of the wavelength used was formed on the aluminum layer.

Next, in the same manner as in Example 1, using a target of a mixture of silicon nitride and silicon dioxide in a weight ratio of 80:20,
Vapor deposition was performed on the reflective film layer by electron beam heating to form a surface protective layer whose optical film thickness was equivalent to 1/4 of the wavelength used.

When a moisture resistance test and a cleaning test were performed on the reflecting mirror B thus obtained in the same manner as in Example 1, almost the same results as those of the reflecting mirror A were obtained.

 The optical characteristics of the reflecting mirror B are shown in FIG.

Example 3 A substrate made of optical glass (BK7) was sufficiently precisely washed and dried, and then attached to a holder and set in a vacuum deposition apparatus. The substrate temperature was 250 ° C., and the degree of vacuum was 1 × 10 ^{−5 to} 3. × 10 ^-5 Tor
Silicon carbide was deposited under the film forming conditions of r to form a lower layer having a thickness of 500 mm.

Subsequently, gold was deposited at a substrate temperature of 200 ° C.
A reflective film layer of 反射 was formed.

Next, in the same manner as in Example 1, using a target of a mixture of silicon nitride and silicon dioxide in a weight ratio of 80:20,
Vapor deposition was performed on the reflective film layer by electron beam heating to form a surface protective layer whose optical film thickness was equivalent to half of the wavelength used.

The sectional configuration of the reflector C thus obtained is as shown in FIG. Here, 1 is a substrate, 2 is a lower layer, 3 is a reflective film layer, and 4 is a surface protective layer.

When a moisture resistance test and a cleaning test were performed on the reflecting mirror C, the results were not inferior to those of the reflecting mirror A. In addition, a film adhesion test using an adhesive tape was performed, but no peeling was observed.

 The optical characteristics of the reflecting mirror C are shown in FIG.

Example 4 Using a substrate made of Pyrex glass, a lower layer of silicon carbide having a thickness of 400 mm was first formed in the same manner as in Example 3.

Subsequently, copper was deposited at a temperature of 200 ° C. to form a reflective film layer having a thickness of 1800 °.

Next, using a target of a mixture of silicon nitride and silicon dioxide in a weight ratio of 85:15 by the same method as in Example 1,
Vapor deposition was performed on the reflective film layer by electron beam heating to form a surface protective layer whose optical film thickness was equivalent to half of the wavelength used.

When a moisture resistance test and a cleaning test were performed on the thus-obtained reflection film D, results almost equivalent to those of the reflection mirror C were obtained.

 FIG. 6 shows the optical characteristics of the reflecting mirror D.

Example 5 Reflector mirrors E, F, G, and H were formed in the same manner as in Example 1, except that a substrate made of copper, tungsten, molybdenum, or silicon whose surface was polished was used.

When a moisture resistance test and a cleaning test were performed on these reflectors E, F, G, and H, almost the same results as those of the reflector A were obtained.

[Comparative Example 1] An example except that a surface protective layer made of silicon oxide having an optical film thickness corresponding to half of the used wavelength was provided in place of the surface protective layer made of silicon nitride and silicon dioxide. A reflector a was prepared in exactly the same manner as in No. 1.

When a moisture resistance test was performed on this reflector a, fogging occurred due to corrosion. When a cleaning test was performed, scratches and peeling occurred.

 FIG. 7 shows the optical characteristics of the reflecting mirror a.

[Comparative Example 2] An example was made except that a surface protective layer made of silicon oxide having an optical film thickness corresponding to 1/4 of the used wavelength was provided in place of the surface protective layer made of silicon nitride and silicon dioxide. A reflector b was prepared in exactly the same manner as in No. 2.

When a moisture resistance test was performed on this reflector b, occurrence of corrosion was observed. In the cleaning test, scratches occurred.

[Comparative Example 3] Using a substrate made of optical glass (BK7), a chromium reflective film layer having a thickness of 80 mm was formed first, and a gold thin film layer having a thickness of 2000 mm was formed in the same manner as in Example 1. Thus, a reflecting mirror c was created.

Although the reflection mirror c passed the moisture resistance test and the film adhesion test, it suffered flaws and partial peeling in the cleaning test.

[Comparative Example 4] Using a substrate made of Pyrex glass, a copper reflective film layer having a thickness of 1800 mm was first formed by the same method as in Example 1, and then the optical film thickness was 1/100 of the wavelength used. A surface protective layer made of silicon dioxide corresponding to No. 4 was provided in a laminated manner to form a reflecting mirror d.

For the reflecting mirror d, corrosion of the film was observed in the moisture resistance test, and scratches were generated in the cleaning test.

〔The invention's effect〕

The reflecting mirror of the present invention has good optical characteristics, adhesion of the film,
It is excellent in moisture resistance, abrasion resistance, chemical resistance and the like, and has high durability, so that there is an advantage that it can be used stably for a long time.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are cross-sectional views showing the configuration of the reflecting mirror of the present invention. 3 to 6 are graphs showing optical characteristics of an example of the reflecting mirror of the present invention, and FIG. 7 is a graph showing optical characteristics of a conventional reflecting mirror as a comparative example. 1 ... substrate, 2 ... lower layer, 3 ... reflective film layer, 4 ... surface protective layer.

Claims (2)

(57) [Claims] A reflective layer comprising a metal layer or a metal layer and a dielectric material layer, and a surface protective layer comprising a mixture of silicon nitride and silicon dioxide are sequentially laminated on a substrate surface of an optical element. A reflecting mirror, comprising: 2. A substrate made of silicon carbide, a lower layer made of silicon carbide, a reflective film layer made of a metal layer and a dielectric material layer, and a surface made of a mixture of silicon nitride and silicon dioxide. A reflecting mirror comprising a protective layer and a protective layer laminated in this order.