JP2001343510A - Metallic reflecting mirror and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the enhancement of the durability and quality of an Ag film or the like deposited on a plastics substrate. SOLUTION: An undercoat 2 comprising a heterogeneous Cr film with a Cr oxide layer whose oxygen content varies in the thickness direction is deposited on a plastics substrate 1 of PC or the like, a metallic reflecting film 3 such as an Ag film is deposited on the undercoat and an overcoat 4 of a dielectric containing Al2O3 or the like is disposed on the reflecting film. Since the lowest layer of the undercoat 2 which adheres to the plastics substrate 1 is a Cr oxide layer having the highest oxygen content and the top layer which adheres to the reflecting film 3 is a Cr layer not containing oxygen, the undercoat 2 has high bonding power to both the substrate and the reflecting film and superior durability is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera, a copying machine,
The present invention relates to a metal reflecting mirror used as an optical component of a printer or the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a metal reflecting mirror used as an optical component of an optical machine such as a camera, a copying machine, a printer, etc. is provided with a uniform oxide undercoat on the surface of a substrate to improve adhesion. In general, a metal reflective film such as Ag, Al, Cu, Au or the like having a high reflectivity is formed thereon, and a protective film of a dielectric material or an enhanced reflective film is further provided thereon.

[0003] In particular, Ag (silver) has the highest reflectivity over the entire visible range and has a property of being hardly oxidized, so that it is considered that there are various merits in practical use. However, when exposed to the atmosphere, a trace amount of sulfur components in the atmosphere causes corrosion or the like by a sulfidation reaction, so that it is difficult to avoid deterioration in a high-temperature and high-humidity environment.

It is known that this tendency is particularly remarkable when the packing density of the Ag film is low or when the surface of the Ag film is rough. In addition, since film strength and solvent resistance are generally low, various measures have been taken to compensate for these.

[0005]

However, according to the above prior art, even if a metal reflective film such as an Ag film is deposited on a so-called resin substrate such as plastic, there is no adhesive force.
As described above, in order to improve the adhesion to a substrate, a uniform undercoat is usually formed in several layers, and a metal film is deposited thereon. Therefore, the film forming process is complicated and the cost is high.

In recent years, a new film forming method other than the vacuum deposition method has been developed. However, the new film forming method requires a new facility. This is not preferable because of the possibility of incorporation.

[0007] It would be economically very effective if an excellent film could be produced by improving the process technology using existing equipment well.

The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and has a high adhesion between a metal reflective film and a substrate, and therefore has a high durability and a reflectance with time. A metal reflecting mirror and a method for manufacturing the same which are suitable for plastic optical components because the substrate can be formed without heating and which can be formed without heating, and which has a simple manufacturing process and low equipment cost, and thus is inexpensive. It is intended to provide.

[0009]

To achieve the above object, a metal reflector according to the present invention comprises a substrate and a metal reflection film laminated on the substrate via an undercoat.
The undercoat is a heterogeneous Cr film having a Cr oxide layer whose oxygen content changes in the film thickness direction.

[0010] In the heterogeneous Cr film, the layer that is in close contact with the substrate is preferably a Cr oxide layer having the highest oxygen content.

[0011] In the heterogeneous Cr film, the layer that is in close contact with the metal reflection film is preferably a Cr layer that does not contain oxygen.

In addition, a substrate and a metal reflection film laminated on the substrate via an undercoat are provided, wherein the undercoat includes a Cr oxide layer having a predetermined oxygen content and a Cr-free layer containing oxygen. A metal reflector having at least two layers may be used.

The method for manufacturing a metal reflector according to the present invention includes a step of forming an undercoat containing Cr as a main component on a substrate in a vacuum evaporation apparatus and forming a metal reflection film thereon.
During the formation of the undercoat, a heterogeneous Cr film is formed by changing the amount of oxygen gas introduced into the vacuum deposition apparatus.

The method further comprises the step of forming an undercoat mainly composed of Cr on a substrate in a vacuum evaporation apparatus, and forming a metal reflection film thereon. In step (2), oxygen gas was introduced into the vacuum deposition apparatus, and in the latter half, the introduction of oxygen gas was stopped.
A method of manufacturing a metal reflecting mirror, which comprises forming a two-layer film composed of an r layer, may be used.

Further, all the film forming steps are performed without heating the substrate in the same vacuum evaporation chamber.

[0016]

The Cr oxide layer, which is the lowermost layer of the undercoat, enhances the bonding strength (adhesion) with the plastic substrate. Since the uppermost Cr layer is a metal film of only Cr,
It has a high bonding force (adhesive force) with a metal reflective film such as a g film, and in addition, greatly contributes to forming a high-quality metal reflective film without defects. As a result, a metal reflector having extremely high durability and high quality can be obtained.

Further, according to the method for manufacturing a metal reflector of the present invention, since it is not necessary to heat the substrate in all the film forming steps, the method is suitable for manufacturing a metal reflector in which the substrate is made of plastic.

Further, since it is not necessary to heat and cool the substrate, the manufacturing process is simple, and the formation of the undercoat can be performed substantially simply by changing the amount of oxygen gas introduced using Cr as an evaporation source. Only the process, the equipment cost is low.

As a result, it is possible to realize a metal mirror which has high durability and high reflection characteristics, does not significantly deteriorate over time, and is lightweight and inexpensive.

[0020]

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

FIG. 1 shows a film configuration of a metal reflecting mirror E ₁ according to the _first embodiment, which is formed from a heterogeneous Cr film formed on the surface of a plastic substrate 1 such as PC (polycarbonate). An undercoat 2 formed on the undercoat 2, a metal reflective film 3 of Ag, Al, Cu, Au or the like formed on the undercoat 2, and an overcoat 4 which is a dielectric film such as an Al ₂ O ₃ film.

The undercoat 2, which is a heterogeneous Cr film,
It has a Cr oxide layer in which the oxygen content changes in the film thickness direction, and the lowermost layer which is in close contact with the surface of the plastic substrate 1 has the highest oxygen content and has a high bonding force (adhesive force) with the plastic substrate 1. . Further, the uppermost portion of the undercoat 2 which is in close contact with the metal reflection film 3 is made of Cr containing almost no oxygen.
This is a layer which has a high bonding force (adhesive force) to the metal reflective film 3 of Ag or the like, and is large for forming a high-quality film free of defects in a film forming process such as an Ag film. To contribute.

As described above, by inserting an undercoat between the metal reflection film and the substrate, which can enhance the bonding force between the two and improve the film quality of the metal reflection film, the durability of the metal reflection mirror and the durability of the metal reflection film are improved. The reflection characteristics can be greatly improved.

The overcoat of an Al ₂ O ₃ film or the like functions to improve the corrosion resistance and solvent resistance of the metal reflection film in the atmosphere.

As a result, it is possible to realize a metal reflector which is made of a lightweight and inexpensive plastic as a base material, has high durability and high reflection characteristics, and does not significantly deteriorate over time.

The film forming process for manufacturing the above-described metal reflecting mirror includes:
It is performed at a low temperature by a known vacuum evaporation apparatus without requiring substrate heating or the like. The step of forming an undercoat made of a heterogeneous Cr film is a substantial step of forming a film while changing the amount of oxygen gas introduced using a Cr evaporation source. That is, after evacuating the vacuum deposition chamber to a predetermined degree of vacuum,
The pressure is adjusted by introducing oxygen gas, and the Cr evaporation source is heated and evaporated by an electron gun or the like to form a Cr oxide layer to a predetermined film thickness. Then, the introduced amount of oxygen gas is gradually reduced. Finally, completely stop the introduction of oxygen gas and
Only adhere.

In this manner, a heterogeneous Cr oxide film having a variable oxygen content is formed in the film thickness direction, a metal reflection film such as Ag is deposited thereon, and further a metal reflection film such as Al ₂ O ₃ is formed. An overcoat is formed.

The process of forming the metal reflection film and the process of forming the overcoat are all performed continuously without heating the substrate in the same vacuum evaporation chamber.

Since the undercoat, the metal reflection film and the overcoat are continuously formed using a vacuum evaporation apparatus generally used conventionally, and it is not necessary to heat the substrate in all the steps. The deposition process is simple,
There is no increase in equipment cost.

That is, a metal mirror having high durability and high reflection characteristics can be manufactured at low cost.

FIG. 2 shows a metal reflector E _{2 according} to a _second embodiment, which is a two-layer undercoat 12 formed on the surface of a plastic substrate 11 such as a PC.
Ag, Al formed on the undercoat 12,
It has a metal reflection film 13 of Cu, Au or the like, and an overcoat 14 which is a dielectric film such as an Al ₂ O ₃ film.

The undercoat 12 having a two-layer structure is composed of a Cr oxide layer 12a having a predetermined oxygen content and a Cr layer 12b containing no oxygen, and the lower layer which adheres to the surface of the plastic substrate 11 is a Cr oxide layer 12a. Yes, the bonding strength (adhesion) with the plastic substrate 11 is high. The upper layer of the undercoat 2 that is in close contact with the metal reflective film 13 is a Cr layer 12b containing no oxygen, which has a high bonding force (adhesive force) to the metal reflective film 13 such as Ag.
This is very useful for forming a high-quality film having no defect in a film forming process such as an Ag film.

As described above, the durability and reflection characteristics of the metal mirror are greatly improved by inserting an undercoat capable of enhancing the bonding force of the metal reflection film to the substrate and improving the film quality of the metal reflection film. it can.

The overcoat such as an Al ₂ O ₃ film functions to improve the corrosion resistance and solvent resistance of the metal reflection film in the atmosphere.

As a result, it is possible to realize a metal reflector which is made of a lightweight and inexpensive plastic as a base material, has high durability and high reflection characteristics, and does not significantly deteriorate with time.

The film forming step for forming the metal reflecting mirror is as follows.
The heating is performed at a low temperature by a known vacuum deposition apparatus without requiring substrate heating. In the formation of a two-layer undercoat, the vacuum evaporation chamber is evacuated to a predetermined degree of vacuum, then oxygen gas is introduced to adjust the pressure, and the Cr evaporation source is heated and evaporated by an electron gun or the like. Oxidation C up to a predetermined film thickness
An r layer is formed, and then the introduction of oxygen gas is completely stopped, and only the Cr layer is deposited.

In this manner, the two layers of the Cr oxide layer and the Cr layer
An undercoat having a layer is formed, a metal reflective film such as an Ag film is adhered thereon, and an overcoat such as an Al ₂ O ₃ film is formed.

The process of forming the metal reflection film and the process of forming the overcoat are all performed continuously in the same vacuum deposition chamber without heating the substrate.

Next, an embodiment will be described.

(Example 1) A substrate made of polycarbonate was
After cleaning by nitrogen blow, 1 ×
10^-3After exhausting to a pressure of Pa or less, the reaction gas
8 × 10^-3Adjust to pressure of Pa
The Cr is heated by an electron gun at this degree of vacuum to form a film having a thickness of 2
Deposit a 0 nm Cr oxide layer and then gradually reduce the amount of oxygen introduced
And stop completely to form a Cr layer as it is
Then, a heterogeneous Cr film having a total film thickness of 40 nm is obtained. Then,
After confirming that the ultimate vacuum was reached, the Ag film was
Deposit 150 nm by resistance heating, then continue as above
1 × 10 ^-2Adjust to a vacuum of Pa
At this degree of vacuum, the electron gun_TwoO_ThreeEtc. dielectric film
Is deposited to a thickness of 120 nm. Above undercoat, metal anti
All evaporation and protective film (overcoat) depositions are based
This was done continuously without heating the plate.

(Example 2) A substrate made of polycarbonate was washed by nitrogen blow, and then washed with a vacuum evaporation apparatus to obtain a 1 × substrate.
After evacuating to a pressure of 10 ⁻³ Pa or less, oxygen gas is introduced from a reaction gas introduction line to adjust the pressure to 8 × 10 ⁻³ Pa.
A Cr oxide layer having a thickness of 20 nm was formed after a 0-nm thick Cr oxide layer was formed.
Form a film. Thereafter, as in Example 1, an Ag film was deposited to a thickness of 150 nm by resistance heating. Subsequently, oxygen gas was introduced to adjust the degree of vacuum to 1 × 10 ⁻² Pa as described above. To form a dielectric film such as Al ₂ O ₃
is formed to a thickness of nm. The deposition of the undercoat, the metal reflective layer, and the overcoat serving as the protective layer were all performed continuously in the same vacuum deposition chamber without heating the substrate.

(Comparative Example 1) A film formation method other than the undercoat film formation was performed in the same manner as in Examples 1 and 2. The undercoat film formation was performed by introducing oxygen and applying a pressure of 8 × 10 ⁻³ Pa. The Cr was heated by an electron gun at this degree of vacuum to form a Cr oxide film having a thickness of 40 nm. As shown in FIG. 3, the film configuration is such that a plastic substrate 31 and a homogeneous Cr oxide
Undercoat 32 as a film and Ag as a metal reflection film
It comprises a film 33 and an overcoat 34 of an Al ₂ O ₃ film.

(Comparative Example 2) The film forming method other than the undercoat film formation was performed in the same manner as in Examples 1 and 2, and the undercoat film was formed by a conventional method of forming a Cr film using an electron gun. The pressure was adjusted to 1 × 10 ⁻³ Pa, and a film was formed at this degree of vacuum. As shown in FIG. 4, the film configuration includes a plastic substrate 41, an undercoat 42 consisting only of a Cr film, an Ag film 43 serving as a metal reflection film, and an overcoat 44 consisting of an Al ₂ O ₃ film.

In both Examples 1 and 2, the evaluation of the adhesion by the tape test after the durability test under constant temperature and humidity was good. In addition, no abnormalities such as cloudiness, film cracking, film peeling, etc. were observed in appearance. On the other hand, in Comparative Examples 1 and 2, Comparative Example 1
From the upper part, Comparative Example 2 was easily peeled off from the substrate side by the adhesion test after the durability test, and it was found that the durability was poor. Table 1 shows the results of the evaluation test.

[0045]

[Table 1]

[0046]

Since the present invention is configured as described above, the following effects can be obtained.

It is possible to realize a metal mirror which has high durability and high reflection characteristics, does not cause the reflectance to decrease with time, and has a simple manufacturing process and is inexpensive.

[Brief description of the drawings]

FIG. 1 is a diagram showing a film configuration of a metal reflecting mirror according to a first embodiment.

FIG. 2 is a diagram showing a film configuration of a metal reflecting mirror according to a second embodiment.

FIG. 3 is a diagram showing a film configuration according to Comparative Example 1.

FIG. 4 is a diagram showing a film configuration according to Comparative Example 2.

[Explanation of symbols]

 1,11 plastic substrate 2,12 undercoat 3,13 metal reflective film 4,14 overcoat

Claims (11)

[Claims] 1. A heterogeneous device comprising: a substrate; and a metal reflection film laminated on the substrate via an undercoat, wherein the undercoat includes a Cr oxide layer having a variable oxygen content in a film thickness direction. A metal reflector characterized by being a Cr film. 2. The metal reflector according to claim 1, wherein, in the heterogeneous Cr film, a layer in close contact with the substrate is a Cr oxide layer having the highest oxygen content. 3. The metal reflector according to claim 1, wherein, in the heterogeneous Cr film, the layer that is in close contact with the metal reflection film is a Cr layer that does not contain oxygen. 4. A substrate comprising: a substrate; and a metal reflection film laminated on the substrate via an undercoat, wherein the undercoat includes a Cr oxide layer having a predetermined oxygen content and a Cr-free layer containing oxygen. A metal reflector having at least two layers. 5. The method according to claim 1, wherein the metal reflection film is an Ag film, an Al film, a Cu film.
5. The metal reflector according to claim 1, wherein the metal reflector includes at least one of a film and an Au film. 6. The metal reflecting mirror according to claim 1, wherein an overcoat made of a dielectric film is provided on the metal reflecting film. 7. The metal reflector according to claim 1, wherein the substrate is a plastic substrate. 8. A step of forming an undercoat containing Cr as a main component on a substrate in a vacuum deposition apparatus, and forming a metal reflection film thereon,
A method for manufacturing a metal reflector, characterized in that a heterogeneous Cr film is formed by changing the amount of oxygen gas introduced into the vacuum evaporation apparatus. 9. A step of forming an undercoat mainly composed of Cr on a substrate in a vacuum evaporation apparatus and forming a metal reflection film thereon, wherein the first half of the undercoat film forming step is performed. In the method for producing a metal reflecting mirror, an oxygen gas is introduced into the vacuum vapor deposition apparatus in the above, and the introduction of the oxygen gas is stopped in the latter half to form a two-layer film composed of a Cr oxide layer and a Cr layer. Method. 10. The method according to claim 8, further comprising the step of forming an overcoat on the metal reflection film. 11. The method according to claim 8, wherein all film forming steps are performed without heating the substrate in the same vacuum evaporation chamber.