JPH02109003A - Reflection mirror - Google Patents

Abstract

PURPOSE:To make adhesion of a light reflection layer to a base body strongly, to improve the resistance of a reflect mirror to environmental changes and to easily facilitate its production by forming an intermediate layer consisting of metal oxide or metal nitride on the base body, laminating a light reflection layer thereon and laminating, if necessary, a protective layer on the light reflection layer. CONSTITUTION:An intermediate layer consisting of metal oxide or metal nitride is formed on a base body, and a light reflection layer is laminated thereon. If necessary, a protective layer is laminated on the light reflection layer. The base body consists of an inorganic material such as glass, several kinds of ceramic material, or metal, or an org. material such as polystyrene, poly(methyl methacrylate), polycarbonate which is formed by casting, etc. The metal oxide to be used for the intermediate layer is such as chrome oxide, titanium oxide, tungsten oxide, tin oxide. A metal such aluminum, gold, silver, copper, or a metal compd. such as titanium nitride, is used for a material for the light reflection layer.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a reflecting mirror that totally reflects light.

More specifically, the attachment of the light reflecting layer to the substrate is strong,
This invention relates to a reflecting mirror with excellent environmental resistance and productivity.

[Background of the Invention t1 In a reflective mirror, it is generally known to use a metal having a high reflectance, such as silver, copper, gold, or aluminum, as a reflective film.

When such a metal reflective film, such as copper (Cu), is provided on a transparent substrate, conventionally, in order to improve the adhesion between the copper and the substrate, chromium, tungsten, or nickel is used as an intermediate layer between the copper and the substrate. , titanium, etc. have been proposed.

However, in this case, if the thickness of the intermediate layer is increased, the light reflectance of the upper metal film decreases, so the thickness of the intermediate layer must be reduced to about 5A to 50A. If the film thickness is limited to
; In this case, the metal film will be insufficiently attached.

Furthermore, while using the reflecting mirror, the problem of film fading occurs, resulting in insufficient environmental resistance.

In order to improve the adhesion between the base made of a synthetic resin member and the metal film, layers of SiJ, Cr and A1 are sequentially formed on this base, and a low refractive material (
Sins) and high refractive materials (TiOl, Ce0z+Ta
*Os or ZrO! After repeatedly forming at least 6 layers of Si and Tie in this order, a surface layer (Si
02) has been proposed.

However, this reflecting mirror has a two-layer metal film structure, which increases the manufacturing cost, and since it uses metallic chromium, there is a limit to the film thickness. However, when polycarbonate is used as the synthetic resin, the coating is insufficient, and when an adhesive tape is attached to the reflective mirror and then peeled off, part of the coating peels off.

[Objective of the Invention 1] The present invention solves the above-mentioned conventional problems and provides a light reflecting layer that is firmly attached to a substrate, has excellent environmental resistance,
It is an object of the present invention to provide a reflecting mirror that is easy to manufacture and has high productivity.

[Structure of the invention] Such an object is to provide an intermediate layer made of a metal oxide or metal nitride on a substrate, to laminate a light-reflecting layer thereon, and to further layer this light-reflecting layer as necessary. This can be achieved by the reflective mirror of the present invention, which has a protective layer laminated thereon.

Substrates used in the reflective mirror of the present invention include, for example, inorganic materials such as glass, various ceramic materials, and metals, or organic polymers such as polystyrene, polymethyl methacrylate, polycarbonate, and acrylonitrile-styrene copolymers. Precision parts made of materials and molded by casting, injection, or other molding methods can be exemplified.

Part 1. Therefore, the reflecting mirror of the present invention using these as a base is shown in Example/l.
For example, it is useful as a 45'' mirror in a laser beam printer, especially in a laser optical system, a polygon mirror in an automobile, and a rear light source mirror in a liquid crystal display.

In the reflective mirror of the present invention, gold a is used as the intermediate layer.
Examples of oxides include chromium oxide, titanium oxide,
Examples include oxides of metals such as tungsten oxide, tin oxide, indium oxide, aluminum oxide, chromium oxide, titanium, tungsten, tin, indium and aluminum, but preferred are chromium oxide or tin oxide. Can give examples of things.

In addition, metal nitrides that can be used as intermediate films in the same way as metal oxides include, for example, chromium nitride, titanium nitride, tungsten nitride, and nitrides of metals such as chromium nitride, titanium nitride, tungsten nitride, titanium, and tungsten. An example of this is chromium nitride.

In the present invention, no particular adverse effects are observed even if the thickness of the intermediate film is made larger than before, so the allowable range can be made wider than before.

The thickness range of this interlayer film is usually 50A to 2000A, preferably 100A to 1000A.

In the reflecting mirror of the present invention, the light reflecting layer laminated on the intermediate layer is made of, for example, a metal such as aluminum, gold, silver, or copper, or a metal compound such as titanium nitride. The thickness of this light reflective layer is usually 500A to 300A.
0 people, preferably 700 to 2000 people.

In the present invention, a protective layer is provided on the light reflective layer as necessary, but this layer is made of silicon oxide 7 (SiOx,
l≦X≦2), and by setting the film thickness (nd) to 1/2 of the reflected light wavelength (λ), an increased reflection effect is produced, which is preferable.

Further, in the present invention, the protective layer is composed of alternating layers of low refractive layers (L layers) and high refractive layers (H layers), and has at least 6
It is also possible to provide a layer in which an even number of layers are laminated, and the optical thickness (nd) of each layer is 1 of the reflected light wavelength (λ).
/2 is preferable.

At this time, it is usually preferable to use sio, mgp, etc. as the L layer, and TiO2, Ce0, etc. as the H layer.
1, Ta□0, or ZrO, and T10. It is preferable to use a mixture with

[Effects of the Invention] Next, to explain the effect I of the present invention in detail, a titanium (Ti) layer or a chromium (C'') layer is formed as an intermediate layer on a transparent substrate such as glass, and then In a conventional reflector made by laminating copper (Cu) ffl (film thickness: 2,000 yen) as a light reflecting layer on a mirror, as the thickness of the intermediate layer increases, the reflectance decreases as already mentioned. .

This relationship is shown using Fig. 1 and Table 1. Fig. 1 shows that a conventional reflecting mirror using Cr as an intermediate layer and Cu (film thickness 200 OA) as a light reflecting layer has a wavelength of 1°. 3μ
When a semiconductor laser beam of l is incident, its angle of incidence is 4
5", the horizontal axis of the figure represents the film thickness (layer) of the C" intermediate layer, and the vertical axis represents the light reflectance (%). The thickness of the intermediate layer is 1
It shows the light reflectance of the reflecting mirror when there are 0 people and 100 people.

As is clear from Table 1, when the film thickness of the Cr intermediate layer increases, the light reflectance decreases significantly for both P-polarized light and S-polarized light.

In this reflector, when polycarbonate is used as the base, when the thickness of the Cr intermediate layer is 10 people, part of the film peels off in a peel test in which adhesive tape is applied and then peeled off, resulting in insufficient film attachment. Met. On the other hand, when the film thickness is 100 mm, the film adhesion is good, but a decrease in reflectance becomes a problem.

This tendency was also the same when a laser beam with a wavelength of 780 nn+ was used.

On the other hand, in the reflector of the present invention, a chromium nitride (CrN) layer is provided as an intermediate layer on the substrate, and an aluminum (AI) layer is laminated thereon as a light reflecting layer with a thickness of 1,000 to 2,000 layers. FIG. 2 and Table 2 show the relationship between the thickness of the CrN intermediate layer and the light reflectance of the mirror when a laser beam with a wavelength of 780 nm is incident at an incident angle of 45 degrees.

Table 2 (Reflector of the present invention) It is possible to extend the allowable limit to a much larger area than before.

Therefore, according to the present invention, it is possible to improve the attachment of the light reflecting layer to the substrate without reducing the light reflectance of the reflecting mirror, and it is also possible to improve the environmental resistance of the reflecting mirror. Can be done.

In addition, in the reflecting mirror of the present invention, the relationship between the film thickness of the CrN intermediate layer and the peeling of the film by the above-mentioned adhesive tape when polycarbonate was used as the base was as shown in Table 3 below.

As is clear from the comparison between Table 2 and Table 1, in the reflecting mirror of the present invention, even if the thickness of the intermediate layer is increased, the rate of decrease in light reflectance is the same as in Table 1 (conventional). It's much less compared to that.

Therefore, in the present invention, the film thickness of the intermediate layer is
...Peeling ○...No peeling In this type of reflecting mirror, it is usually necessary to obtain a light reflectance of 85% or more. To this end, the thickness of the CrN intermediate layer in the reflector of the present invention in 8 is preferably selected appropriately within the range of 50 to 1500, taking into account the tape removability shown in Table 3.

The effects of the present invention when chromium nitride (Cr?J) is used as the intermediate layer have been explained above.
The optimum film thickness for each test conducted in the same manner as in the case of rN) is shown in Table 4 below.

Table 4 (Reflector of the present invention) According to the present invention, after providing an intermediate layer made of a metal oxide or metal nitride on a substrate and laminating a light reflecting layer thereon,
On top of this light-reflecting layer, silicon oxide (SiOx, 1≦
A protective film consisting of X≦2) is provided, and its optical film thickness (ad)
is the reflected light wavelength (λ), for example 1.780n+n. /2, the light reflectance can be increased by 3 to 5% compared to the case where this protective film is not provided.

Further, in this case, it is also possible to improve the environmental resistance of the reflecting mirror.

Furthermore, in the present invention, a low refractive layer (L layer,
) and a low refractive layer (H
The light reflectance of the mirror can also be increased by providing a protective film consisting of repeated layers.

Therefore, in the present invention, such a protective film can be further provided on the light reflecting layer, if necessary.

[Example 1] Next, the present invention will be specifically explained with reference to Examples, but it goes without saying that the present invention is not limited to these.

In each of the following examples, a high frequency ion plate (Fugu method) was applied to form the intermediate layer, light reflective layer, protective layer, etc., but the present invention is limited to this film forming method. However, other film forming methods such as sputtering can also be applied.

Example 1 A molded polycarbonate resin member was used as a base, and a chromium nitride layer was formed as an intermediate layer on this base using a high-frequency ion plate (Fugu method) by heating and evaporating a chromium evaporation source with an electron gun. The membrane striae properties were as follows.

Next, a light reflecting layer (A1 layer) and a protective layer (Si03 layer) were sequentially formed on this chromium nitride intermediate layer under the conditions shown below to create a reflecting mirror of the present invention.

When a semiconductor laser beam with a wavelength of 7,800 wavelengths is incident on the reflector made in this way at an incident angle of 45'', the light reflectance is 88% to 86% (P polarized light) and 89% to 87%.
(S polarized light).

Also, in a peel test in which adhesive tape was pasted on the reflective mirror and then peeled off, no peeling of the film was observed, indicating that the film was well attached.

In addition, the reflector was placed in an environment with a temperature of 60°C and humidity of 90%.
Even when the film was left for 4 hours (environmental resistance test), no deterioration in the releasability was observed.

Example 2 A molded member of polymethyl methacrylate resin is used as a base,
A tin oxide layer was formed as an intermediate layer on the upper surface of this substrate by high-frequency ion blasting, by heating and evaporating a tin evaporation source with an electron gun. The film forming conditions were as per the boundary test in Example 1.
When conducted under the same conditions as in Example 1, good results similar to those in Example 1 were obtained.

Example 3 A polycarbonate I/resin molded member was used as a base, and a titanium nitride layer was formed as an intermediate layer on this base by high-frequency ion plate (Fugu method) by heating and evaporating a titanium evaporation source with an electron gun. The film forming conditions were as follows: and protective layer (Sin,
layers) were sequentially formed under exactly the same conditions as in Example 1 to create a reflective mirror of the present invention. When a semiconductor laser beam with a wavelength of 7800A is incident on the reflector thus prepared at an incident angle of 45'', the light reflectance is 87% to 85%.
% (P polarized light) and 88% to 85% (S polarized light).

Then, the peel test and ring resistance (A1
A reflective mirror of the present invention was produced by sequentially forming a protective layer (Sin layer) and a protective layer (Sin layer) under exactly the same conditions as in Example 1.

When a semiconductor laser beam with a wavelength of 7800 A is incident at an incident angle of 45° on the reflector thus created, the light reflectance is 89% to 85% (P polarized light), 89% to 8
It was 6% (S polarized light).

Then, when the peel test and environmental resistance test shown in Example 1 were conducted under the same conditions as in Example 1, good results similar to those in Example 1 were obtained.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the relationship between the film thickness of the chromium intermediate layer (Cr layer) and the light reflectance of the reflecting mirror in a conventional reflecting mirror,
The horizontal axis of the figure represents the film thickness (in thickness) of the chromium intermediate layer (Cr layer), and the vertical axis represents the light reflectance (%) of the reflecting mirror. FIG. 2 is a diagram showing the relationship between the film thickness of the intermediate layer and the light reflectance of the reflective mirror in the reflective mirror of the present invention. Represents the light reflectance (%) of a reflecting mirror.

Claims (6)

[Claims] (1) A reflecting mirror comprising an intermediate layer made of a metal oxide provided on a substrate, a light reflecting layer laminated thereon, and, if necessary, a protective layer laminated on the light reflecting layer. (2) Claim 1 uses an oxide of a metal selected from the group consisting of chromium, titanium, tungsten, tin, indium, and aluminum as the metal oxide.
Reflector described in ). (3) The reflecting mirror according to claim (1) or (2), in which the light reflecting layer is made of aluminum, gold, silver, copper, or titanium nitride. (4) A reflecting mirror comprising an intermediate layer made of metal nitride provided on a base, a light reflecting layer laminated thereon, and further a protective layer laminated on this light reflecting layer as required. (5) The reflecting mirror according to claim (4), wherein the metal nitride is a metal nitride selected from the group consisting of chromium, titanium, and tungsten. (6) The reflecting mirror according to claim (4) or (5), in which the light reflecting layer is made of aluminum, gold, silver, copper, or titanium nitride.