JP2011221207A - Aluminum surface reflection mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a film structure that entirely satisfies humidity resistance, heat resistance and light resistance such that mechanical deterioration and functional deterioration of a film can be suppressed even in a harsh usage environment.SOLUTION: A reflection mirror is configured such that an adhesion layer 2, a reflection layer 3 made of an aluminum film and a dielectric layer 4 are stacked in this order on a resin substrate 1. The adhesion layer 2 is composed of two layers, and is configured such that a first layer 2a and a second layer 2b are stacked in this order from the side of the resin substrate 1. The first layer 2a is composed of a cerium oxide film, and the second layer 2b is composed of a layer made of a mixture of titanium oxide and praseodymium oxide.

Description

  The present invention relates to an aluminum surface reflecting mirror in which an adhesion layer is formed between a resin substrate and a reflecting layer made of aluminum.

  In recent years, plastic substrates have been used instead of glass substrates as reflector substrates. This is because, if it is a plastic substrate, a free curved surface can be easily formed, and the cost can be reduced compared to glass. However, the metal surface reflecting mirror in which a metal such as aluminum, silver, gold, or copper is directly formed on such a plastic substrate is easy to peel off the metal film from the substrate, and has an environment resistance such as heat resistance, moisture resistance, and light resistance. Inferiority was a problem.

  Therefore, in Patent Documents 1 to 5, for example, an adhesion layer is formed between the plastic substrate and the metal film, and a protective layer is formed on the metal film, thereby improving the adhesion between the plastic substrate and the metal film. To improve the environmental resistance. More details are as follows.

  In Patent Document 1, an oxide base layer made of cerium oxide (film thickness 15 nm), a reflective layer made of aluminum (film thickness 100 nm), and a protective layer made of aluminum oxide (film thickness 20 nm) are formed on a substrate made of polycarbonate. Formed in order.

  In this configuration, in an environment of 40 ° C. and 95% RH (relative humidity), the time until the film is peeled off by the cellophane tape is 504 hours or more, and the film adhesion and moisture resistance are high. Further, it is known that there is almost no change in the spectral reflectance with respect to 45-degree incident light before and after the moisture resistance test. Furthermore, even when silicon dioxide is used instead of cerium oxide as the oxide underlayer, the time until the film peels in an environment of 40 ° C. and 95% RH is 312 hours or more, and film adhesion and moisture resistance Is expensive.

  In Patent Document 2, on a substrate made of cycloolefin resin, a base layer made of aluminum oxide (film thickness 68 nm), an adhesion layer made of copper (film thickness 40 nm), a reflective layer made of silver (film thickness 150 nm), an oxide A reflection-enhancing layer composed of two layers of aluminum (optical film thickness 110 nm) and titanium oxide (optical film thickness 110 nm) and a protective layer (film thickness 21 nm (optical film thickness 30 nm)) made of silicon dioxide are formed in this order. . In addition, the base layer, the increased reflection layer, and the protective layer are formed by IAD (ion-assisted vapor deposition). The metal constituting the reflective layer may be aluminum.

In this configuration, in the evaluation of adhesion by a cross-cut tape test (based on JIS K5400), 100 squares (one square; 1 mm ² ) formed on the substrate surface (film formation surface) are adhesive tapes. All remains without being peeled by the film, and the adhesion is good. Further, a reflectance of 95% or more is ensured, a decrease in reflectance after an abrasion test (according to MIL M-13508), and a substrate after film formation in an atmosphere of 95% humidity at 60 ° C. The decrease in the reflectance after leaving for 240 hours is within 1%, and the wear and moisture resistance are good.

  In Patent Document 3, on a plastic substrate made of acrylic resin, a base film made of silicon monoxide (thickness of several thousand mm (1 mm = 0.1 nm)), a metal film made of aluminum (thickness of several thousand mm), dioxide A protective layer (thickness of about 5000 mm) made of silicon is formed in this order. Thus, by interposing the base film made of silicon monoxide between the plastic substrate and the metal film, the adhesion of the metal film to the plastic substrate is improved.

  In Patent Document 4, a base film made of aluminum oxide (for example, a film thickness of 100 nm), an adhesion layer made of two layers of chromium (for example, a film thickness of 10 nm) and copper (for example, a film thickness of 30 nm), and a reflection made of silver on a plastic substrate. A film (for example, a film thickness of 100 nm), an aluminum oxide film, a zirconium oxide film, a silicon dioxide film, a reflectance adjusting layer composed of three layers, and a water-repellent film (for example, a film thickness of 5 nm) having a fluorine-containing silicon compound are formed in this order. ing.

  With this configuration, in both the high temperature test and the temperature cycle test, there is no problem that hinders practical use on the film formation surface. In addition, the high temperature test is performed by confirming the presence or absence of cracks or peeling on the film formation surface after 5 hours at a temperature of 70 ° C. In the temperature cycle test, the reflector is held at −20 ° C. for 2 hours, then heated to 65 ° C. in 2 hours, held at 65 ° C. for 2 hours, and further cooled to −20 ° C. in 2 hours. The temperature cycle is repeated eight times, and the presence or absence of cracks or peeling on the film formation surface is confirmed.

  In Patent Document 5, a base layer made of silicon monoxide (film thickness 50 nm), a chromium film (film thickness 5 nm), a silver reflective film (film thickness 150 nm), and a chromium film (film thickness 2 nm) on a substrate made of polycarbonate. ), A protective layer composed of two layers of an aluminum oxide film (film thickness 100 nm) and a silicon dioxide film (film thickness 10 nm) is formed in this order. In this configuration, the reflectivity hardly decreases after 500 hours in an environment of a temperature of 60 ° C. and a humidity of 90%.

JP-A-3-239201 (see Examples 5 and 8) JP 2008-260978 A (see paragraphs [0009], [0013] to [0015], [0025], [0026], Example 2 etc.) JP-A-52-40348 (see page 2, upper left column, upper right column, etc.) JP 2004-219974 (see paragraphs [0015] to [0036], [0067] to [0071], etc.) JP-A-8-234004 (see paragraphs [0020] to [0034], [0042], etc.)

  By the way, when the metal surface reflecting mirror is used for, for example, an in-vehicle application (for example, a room mirror), considering that the interior of the vehicle in summer becomes a high temperature and humidity environment or a high temperature environment, the metal surface reflection mirror is in a high temperature and humidity environment (for example, 85 The film structure is required to suppress mechanical deterioration (peeling, cracks) of the film and functional deterioration such as a decrease in reflectance even in a high-temperature environment (for example, 115 ° C.). In particular, it is desirable to ensure 90% or more of the average reflectance in the visible light region of 420 nm to 700 nm.

  However, when the present inventors conducted a moisture resistance test assuming a high-temperature and high-humidity environment of 85 ° C. and 85% RH and a heat resistance test assuming a high-temperature environment of 115 ° C., the present inventors etc. The film floated (peeled) during the property test, and cracks occurred during the heat resistance test, and the above requirements could not be satisfied.

  In addition, when using a metal surface reflector for in-vehicle applications, it is necessary to consider the influence of ultraviolet rays, and it is also necessary to have a film configuration that can suppress mechanical deterioration and functional deterioration of the film due to ultraviolet rays. Is done.

  The present invention has been made to solve the above-described problems, and its purpose is to realize a film configuration that satisfies all of moisture resistance, heat resistance, and light resistance, and is suitable for high temperature and high humidity environments, high temperature environments, and ultraviolet rays. An object of the present invention is to provide an aluminum surface reflecting mirror capable of suppressing mechanical deterioration and functional deterioration of a film even under severe conditions of use such as an affected environment.

  The aluminum surface reflecting mirror of the present invention is formed by laminating an adhesive layer, a reflective layer made of an aluminum film, and a dielectric layer in this order on a resin substrate, and the adhesive layer is composed of two layers. A first layer and a second layer are laminated in this order from the resin substrate side, the first layer is composed of a cerium oxide film, and the second layer is composed of titanium oxide and It is characterized by comprising a layer made of a mixture with praseodymium oxide.

  In the aluminum surface reflecting mirror of the present invention, the dielectric layer is composed of a dielectric multilayer film in which a low refractive index layer and a high refractive index layer are laminated, and the low refractive index layer contains silicon dioxide. The high refractive index layer is preferably composed of any one of a layer containing titanium oxide, a layer made of zirconium oxide, and a layer made of tantalum oxide.

  According to the present invention, by forming a cerium oxide film on the resin substrate as the first layer of the adhesion layer, the resin substrate and the multilayer film (reflective layer, dielectric layer) can be separated from each other in a high temperature and high humidity environment. And functional deterioration of the reflective layer due to moisture (decrease in reflectance) can be suppressed. Further, by forming a layer made of a mixture of titanium oxide and praseodymium oxide as the second layer of the adhesion layer, the effect of suppressing the penetration of moisture from the resin substrate side and suppressing the functional deterioration of the reflective layer, The effect of reducing the occurrence of cracks in a high temperature environment and the effect of suppressing a decrease in the adhesion between the resin substrate and the reflective layer can be expected in an environmental resistance test (including tests on moisture resistance, heat resistance, and light resistance). Furthermore, by forming a dielectric layer on the reflective layer, it is possible to suppress the intrusion of moisture, sulfur, and the like from the outside to suppress the functional deterioration of the reflective layer and improve the mechanical strength.

  As described above, the film structure that combines the structure in which the adhesion layer composed of two layers is formed between the resin substrate and the reflective layer and the structure in which the dielectric layer is formed on the reflective layer provides a moisture resistance, heat resistance, An aluminum surface reflecting mirror that satisfies all light resistance can be realized, and mechanical and functional deterioration of the film can be suppressed even under severe conditions such as in-vehicle use.

It is sectional drawing which shows the schematic structure of the reflective mirror which concerns on one Embodiment of this invention. It is explanatory drawing which shows the film | membrane structure and the result of an environmental test about the reflective mirror of Examples 1-5. It is explanatory drawing which shows the film | membrane structure and the result of an environmental test about the reflective mirror of Examples 6-8. It is explanatory drawing which shows the film | membrane structure and the result of an environmental test about the reflective mirror of Comparative Examples 1-5. It is explanatory drawing which shows the film | membrane structure and the result of an environmental test about the reflective mirror of Comparative Examples 6-10. It is explanatory drawing which shows the film | membrane structure and the result of an environmental test about the reflective mirror of Comparative Examples 11-13. It is explanatory drawing which shows the change of the reflectance with respect to the wavelength before and after each test in the reflective mirror of Example 1, and the change of the reflectance with respect to the wavelength after the moisture resistance test in the reflective mirror of Comparative Example 1.

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

[Configuration of reflector]
FIG. 1 is a cross-sectional view showing a schematic configuration of an aluminum surface reflecting mirror (hereinafter also referred to as a reflecting mirror) according to an embodiment of the present invention. The reflecting mirror of this embodiment is configured by laminating an adhesion layer 2, a reflecting layer 3, and a dielectric layer 4 in this order on a resin substrate 1. In the present embodiment, the reflective layer 3 is made of an aluminum film.

  The resin substrate 1 is composed of a plastic substrate using a resin material such as polycarbonate (PC), cycloolefin polymer resin, or cyclic olefin resin.

  The adhesion layer 2 includes two layers, and is configured by laminating a first layer 2a and a second layer 2b in this order from the resin substrate 1 side. The first layer 2a is composed of a cerium oxide film, and the second layer 2b is composed of a layer made of a mixture of titanium oxide and praseodymium oxide.

  The dielectric layer 4 is composed of a dielectric multilayer film in which a low refractive index layer and a high refractive index layer are laminated. Here, the refractive index of the low refractive index layer is 1.35 to 1.60, and the high refractive index layer has a higher refractive index than the low refractive index layer. In the present embodiment, the dielectric layer 4 is composed of three layers, and from the resin substrate 1 side, the first low refractive index layer 4a (first L layer) containing silicon dioxide and the high refractive index containing titanium oxide. The refractive index layer 4b (H layer) and the second low refractive index layer 4c (second L layer) containing silicon dioxide are laminated in this order. In addition to the layer containing titanium oxide, the high refractive index layer may be composed of a layer composed of zirconium oxide or a layer composed of tantalum oxide.

  Note that the low refractive index layer containing silicon dioxide may be a layer formed using only silicon dioxide, or formed using a mixture of silicon dioxide and another material (for example, aluminum oxide). It may be a layer. Further, the high refractive index layer containing titanium oxide may be a layer formed using only titanium oxide, or formed using a mixture of titanium oxide and another material (for example, lanthanum oxide). It may be a layer.

  By forming a cerium oxide film on the resin substrate 1 as the first layer 2a of the adhesion layer 2, an effect of suppressing a decrease in adhesion between the resin substrate 1 and the reflective layer 3 due to water absorption of the resin substrate 1 itself; The effect of suppressing the penetration of moisture from the resin substrate 1 to the reflective layer 3 can be expected. As a result, in a high temperature and high humidity environment, peeling between the resin substrate 1 and the multilayer film (the reflective layer 3 and the dielectric layer 4) formed on the resin substrate 1 is suppressed, and the functional degradation (reflection) of the reflective layer 3 due to moisture is suppressed. (Decrease in rate) can be suppressed.

  In addition, by forming a layer made of a mixture of titanium oxide and praseodymium oxide as the second layer 2b of the adhesion layer 2, the penetration of moisture from the resin substrate 1 side is suppressed and the functional deterioration of the reflective layer 3 is reduced. In the effect of suppressing, the effect of reducing the occurrence of cracks in a high temperature environment, and the environmental resistance test such as a moisture resistance test, a heat resistance test, and a light resistance test described later, the adhesion strength between the resin substrate 1 and the reflective layer 3 is reduced. We can expect the effect to suppress.

  Further, since the dielectric layer 4 is formed on the reflective layer 3, it is possible to prevent moisture and sulfur from entering the reflective layer 3 from the outside, and the functional of the reflective layer 3 due to moisture and sulfur. Deterioration can be prevented. Further, the dielectric layer 4 can prevent the reflective layer 3 from being damaged by an external factor, and the effect of improving the mechanical strength can also be obtained.

  Therefore, as described above, a film structure in which the structure in which the adhesive layer 2 including two layers is provided between the resin substrate 1 and the reflective layer 3 and the structure in which the dielectric layer 4 is formed on the reflective layer 3 is combined. In addition, it is possible to realize a reflecting mirror having good environmental resistance such as moisture resistance, heat resistance, and light resistance. Thereby, for example, even when the usage environment of the reflecting mirror is severe, such as in-vehicle use, it is possible to suppress functional deterioration such as mechanical deterioration (peeling, cracking) and reflectance reduction of the film constituting the reflecting mirror.

  In particular, when the dielectric layer 4 is composed of a dielectric multilayer film in which a low refractive index layer and a high refractive index layer are alternately laminated, an increased reflection effect can be obtained, and the function as a reflecting mirror is further improved. be able to. That is, it is possible to reliably avoid a decrease in reflectance even in a severe environment.

  In addition, by forming each layer under the preferable conditions shown below, after the moisture resistance test, heat resistance test, and light resistance test described later, an average reflectance of 90% or more in the visible light region of 420 nm to 700 nm can be reliably realized. Can do.

[Preferred conditions for each layer]
The cerium oxide film as the first layer 2a of the adhesion layer 2 preferably has a physical film thickness of 5 nm or more, and a physical film thickness of 20 nm or more from the viewpoint of preventing moisture penetration and improving adhesion. It is more preferable to have. Further, the cerium oxide film as the first layer 2a preferably has a physical film thickness of 150 nm or less from the viewpoint of preventing film cracking and film floating, and in particular, if the physical film thickness is 70 nm or less. It is more preferable because the effect of preventing cracks in a high temperature environment is enhanced.

  Further, the second layer 2b of the adhesion layer 2, that is, a layer made of a mixture of titanium oxide and praseodymium oxide has a physical film thickness of 5 nm or more from the viewpoint of preventing moisture penetration and improving adhesion. In particular, a physical film thickness of 18 nm or more is more preferable because adhesion in a high-temperature and high-humidity environment is improved and reliability is improved. Further, the second layer 2b made of the above mixture preferably has a physical film thickness of 40 nm or less, and has a physical film thickness of 28 nm or less, from the viewpoint of preventing film cracking and film floating. It is more preferable. In addition, when using the IAD (Ion Assist Deposition) method, if the physical thickness of the second layer 2b is 15 nm or more and 25 nm or less, the crack prevention effect in a high temperature environment and the decrease in adhesion in a high temperature and humidity environment are caused. Since the prevention effect can be obtained remarkably, it is more preferable.

  From the viewpoint of obtaining a high reflectance, the aluminum film as the reflective layer 3 preferably has a physical film thickness of 40 nm or more, and more preferably has a physical film thickness of 50 nm or more. In addition, the aluminum film as the reflective layer 3 preferably has a physical film thickness of 200 nm or less from the viewpoint of preventing film cracking and film floating. In particular, if the physical film thickness is 80 nm or less, the aluminum film It is more preferable because the occurrence of cracks under the environment can be suppressed and the reliability is improved.

  The first low refractive index layer 4a and the second low refractive index layer 4c of the dielectric layer 4 are preferably silicon dioxide films formed without introducing oxygen. The reason is that when the silicon dioxide film is formed without introducing oxygen into the vacuum chamber, the heat resistance performance is improved. The high refractive index layer 4b is particularly preferably composed of a mixture of titanium oxide and lanthanum oxide from the viewpoint of improving mechanical resistance (mechanical strength).

  When the reference wavelength λ is 500 nm, the dielectric layer 4 has an optical film thickness of 0.1 to 4 with respect to 4 nd / λ (n: refractive index, d: physical film thickness (nm)). Preferably, when an excellent reflecting mirror is formed, it is preferable to form a multilayer structure as the increased reflection layer. In particular, in the case of forming the increased reflection layer with a three-layer structure, the optical film thickness of the first low refractive index layer is 1, the optical film thickness of the high refractive index layer is 1, and the second The optical film thickness of the low refractive index layer is preferably 0.3. In the present embodiment, the dielectric layer 4 has a three-layer structure, and each layer has the above-described optical film thickness, so that the effect as an increased reflection layer appears remarkably.

  As a method for forming the adhesion layer 2, the reflective layer 3, and the dielectric layer 4 described above, a known method such as a vacuum deposition method, a sputtering method, a chemical vapor deposition method, or the like can be used. In particular, the use of an IAD (Ion Assist Deposition) method is more preferable because the film becomes denser and an improvement in environmental resistance is expected.

[Examples and Comparative Examples]
Next, examples and comparative examples of the reflecting mirror will be described as Examples 1 to 8 and Comparative Examples 1 to 13.

(Example 1)
First, a cerium oxide film having a physical thickness of 30 nm is formed on the resin substrate 1 made of polycarbonate as the first layer 2a of the adhesion layer 2 by the IAD method, and subsequently vapor deposition made of a mixture of titanium oxide and praseodymium oxide. A second layer 2b having a physical film thickness of 20 nm was formed by IAD method using OH-10 (manufactured by Canon Optron) as a material.

  Next, an aluminum film having a physical thickness of 70 nm was formed as the reflective layer 3 on the adhesion layer 2 formed of such a multilayer film by resistance heating vapor deposition using an aluminum material. Then, a dielectric multilayer film of the dielectric layer 4 having the effect of increasing reflection was formed on the reflective layer 3 by electron beam evaporation. Specifically, a silicon dioxide film having a physical film thickness of 88 nm is formed as the first low refractive index layer 4a of the dielectric layer 4, and subsequently, the physical film thickness is formed using H4 which is a vapor deposition material manufactured by Merck. A 65 nm high refractive index layer 4b was formed, and a silicon dioxide film having a physical thickness of 26 nm was further formed thereon as a second low refractive index layer 4c. H4 is a material composed of a mixture of titanium oxide and lanthanum oxide. In Example 1, the refractive index of the first low refractive index layer 4a and the second low refractive index layer 4c is 1.46, and the refractive index of the high refractive index layer 4b is 1.90.

(Example 2)
A reflective mirror was produced under the same conditions as in Example 1 except that ZEONOR (registered trademark; ZEON CORPORATION), which is a cycloolefin polymer resin, was used as the resin substrate 1.

(Example 3)
A reflecting mirror was produced under the same conditions as in Example 1 except that Arton (registered trademark; JSR Corporation), which is a cyclic olefin resin, was used as the resin substrate 1.

Example 4
The first layer 2a (cerium oxide film, physical film thickness 30 nm) of the adhesion layer 2 is formed by electron beam evaporation, and the second layer 2b (OH-10, physical film thickness 23 nm) is formed by electron beam evaporation. Produced a reflecting mirror under the same conditions as in Example 1.

(Example 5)
A reflective mirror was produced under the same conditions as in Example 1 except that the reflective layer 3 was formed by electron beam evaporation using an aluminum material.

(Example 6)
Reflective mirror under the same conditions as in Example 1 except that the first low refractive index layer 4a and the second low refractive index layer 4c of the dielectric layer 4 are formed using L5 which is a vapor deposition material manufactured by Merck. Was made. L5 is a material composed of a mixture of silicon dioxide and aluminum oxide. In Example 6, the refractive index of the first low refractive index layer 4a and the second low refractive index layer 4c is 1.47.

(Example 7)
A reflecting mirror was produced under the same conditions as in Example 1 except that the high refractive index layer 4b of the dielectric layer 4 was formed of tantalum oxide (Ta ₂ O ₅ ) having a physical thickness of 60 nm. In Example 7, the refractive index of the high refractive index layer 4b is 2.05.

(Example 8)
A reflecting mirror was produced under the same conditions as in Example 1 except that the high refractive index layer 4b of the dielectric layer 4 was formed of zirconium oxide (ZrO ₂ ) having a physical film thickness of 65 nm. In Example 8, the refractive index of the high refractive index layer 4b is 1.90.

(Comparative Example 1)
With reference to the film configuration of Patent Document 3, a silicon monoxide film having a physical thickness of 50 nm is formed as an adhesion layer on a resin substrate made of polycarbonate, and an electron beam using an aluminum material is formed on the adhesion layer. A reflective layer was formed by vapor deposition. Other film configurations are the same as those in the first embodiment.

(Comparative Example 2)
With reference to the film configuration of Patent Document 4, an aluminum oxide film having a physical film thickness of 11 nm, a chromium film having a physical film thickness of 5 nm, and a copper film having a physical film thickness of 22 nm are arranged in this order on a resin substrate made of polycarbonate. Formed with. The film configuration other than the adhesion layer is the same as in Comparative Example 1.

(Comparative Example 3)
With reference to the film configuration of Patent Document 5, a silicon monoxide film having a physical film thickness of 50 nm and a chromium film having a physical film thickness of 5 nm were formed in this order as an adhesion layer on a resin substrate made of polycarbonate. The film configuration other than the adhesion layer is the same as in Comparative Example 1.

(Comparative Example 4)
An adhesion layer having a physical thickness of 20 nm was formed on a resin substrate made of polycarbonate by IAD method using OH-10. The film configuration other than the adhesion layer is the same as that of the first embodiment.

(Comparative Example 5)
The same as Comparative Example 4 except that ZEONOR was used as the resin substrate.

(Comparative Example 6)
The same as Comparative Example 4 except that Arton was used as the resin substrate.

(Comparative Example 7)
On the resin substrate made of polycarbonate, an aluminum oxide (Al ₂ O ₃ ) film having a physical thickness of 20 nm is formed as the first layer of the adhesion layer, and subsequently, the physical film thickness is 20 nm by IAD method using OH-10. A second layer of was formed. The film configuration other than the adhesion layer is the same as that of the first embodiment.

(Comparative Example 8)
The same as Comparative Example 7, except that a zirconium oxide (ZrO ₂ ) film having a physical thickness of 20 nm was formed as the first layer of the adhesion layer.

(Comparative Example 9)
The same as Comparative Example 7, except that an yttrium oxide (Y ₂ O ₃ ) film having a physical thickness of 20 nm was formed as the first layer of the adhesion layer.

(Comparative Example 10)
The same as Comparative Example 7, except that a silicon dioxide (SiO ₂ ) film having a physical thickness of 20 nm was formed by the IAD method as the first layer of the adhesion layer.

(Comparative Example 11)
On the resin substrate made of polycarbonate, a first layer having a physical film thickness of 20 nm is formed by IAD method using OH-10 as an adhesion layer, and subsequently, silicon dioxide having a physical film thickness of 20 nm is formed as the second layer. A (SiO ₂ ) film was formed by the IAD method. The film configuration other than the adhesion layer is the same as that of the first embodiment.

(Comparative Example 12)
A cerium oxide film having a physical thickness of 30 nm is formed as a first layer of the adhesion layer on the resin substrate made of polycarbonate by the IAD method, and subsequently, a second film having a physical thickness of 20 nm is formed by the IAD method using OH-10. Further, as a third layer, a cerium oxide film having a physical thickness of 20 nm was formed by the IAD method. The film configuration other than the adhesion layer is the same as that of the first embodiment.

(Comparative Example 13)
A cerium oxide film having a physical film thickness of 30 nm is formed on the resin substrate made of polycarbonate by the IAD method as a first layer of the adhesion layer, and then an aluminum oxide film (Al ₂ film having a physical film thickness of 100 nm is formed as the second layer. O _x (x = 1 to 3) was formed, and a third layer having a physical thickness of 20 nm was formed by IAD using OH-10. The film configuration other than the adhesion layer is the same as that of the first embodiment.

  2 shows the reflecting mirrors of Examples 1 to 5, FIG. 3 shows the reflecting mirrors of Examples 6 to 8, FIG. 4 shows the reflecting mirrors of Comparative Examples 1 to 5, and FIG. FIG. 6 is an explanatory diagram showing the film configuration and the results of the environmental test for the reflecting mirrors of Comparative Examples 11 to 13.

2 to 6, the notation “SiO ₂ ” indicates that the SiO ₂ film is formed without introducing oxygen into the vacuum chamber. “H4” indicates a film formed of a material composed of a mixture of titanium oxide and lanthanum oxide, which is a vapor deposition material manufactured by Merck. “L5” indicates a film formed of a material made of a mixture of silicon dioxide and aluminum oxide, which is a vapor deposition material manufactured by Merck. The notation “−EB” indicates that the film is formed by electron beam evaporation, the notation “−RH” indicates that the film is formed by resistance heating evaporation, and “−IAD” indicates the IAD method. It shows that the film is formed using The notation “AL (O ₂ )” means an aluminum oxide film formed by aluminum vapor deposition in an oxygen atmosphere using aluminum instead of aluminum oxide as a vapor deposition material. “PC” as a substrate material indicates polycarbonate. “OH-10” is a layer formed using OH-10, and is a layer made of a mixture of titanium oxide and praseodymium oxide. Hereinafter, the term “OH-10” refers to a layer formed using OH-10 unless otherwise specified as an evaporation material.

  As the environmental test, a moisture resistance (high temperature and humidity resistance) test, a heat resistance test, and a light resistance test (fade meter test) were performed. In the moisture resistance test, the reflecting mirror was left in an atmosphere of 85 ° C. and 85% RH for 500 hours, and the appearance and tape were evaluated. The appearance was evaluated by observing the presence or absence of visual defects. The above-mentioned defects include those that mean film deterioration such as scratches, pinholes, partial cracks, film floating, and cloudiness. Evaluation with a tape was performed by observing the adhesiveness (degree of peeling) of the cellophane tape when the cellophane tape was peeled off after the cellophane tape (Nichiban L-pack) was adhered to the membrane with the belly of the finger.

In the heat resistance test, the reflector was left in an atmosphere at 115 ° C. for 500 hours, and the appearance and tape were evaluated in the same manner as in the humidity resistance test. In the light resistance test, the reflecting mirror was left in the fade meter for 500 hours, and the appearance and tape were evaluated in the same manner as the humidity resistance test. In the fade meter, a UV long life carbon arc lamp with a single-sided irradiance of 500 ± 100 W / m ² was used as the light source, and the sample (reflecting mirror) was placed at a distance of 25 cm from the light source in a testing machine within 63 ± 3 ° C. ) Were placed facing each other and irradiated with ultraviolet rays.

  The reflectance was also evaluated before and after each of the above tests. The reflectivity was evaluated by measuring the reflectivity at 30 ° incidence in a visible light region of 420 nm to 700 nm using a Hitachi spectrophotometer U-4100.

  In the evaluation of the appearance in each test of FIG. 2 to FIG. 6, “◎” indicates that there is no defect in appearance, and “◯” indicates that it is good but can be confirmed by gazing. It indicates that there is a defect, and “x” indicates that there is an obvious defect. In the evaluation by tape, “◎” indicates that there is no peeling by tape and is good, “◯” indicates that there is fine peeling that is good but can be confirmed by gazing, and “×” indicates , Indicating complete film delamination.

  Furthermore, in the evaluation of reflectance, ““ ”indicates that the average reflectance in the visible light region of 420 nm to 700 nm is 90% or more after any environmental test, and“ × ”indicates three environmental tests. It is indicated that at least one of the latter results in the above average reflectance being less than 90%.

  It can be seen that in Comparative Examples 1 to 3, the adhesion of the film is lowered in a high-temperature and high-humidity environment. From Comparative Examples 4 to 6, it can be seen that OH-10 is relatively strong in a high temperature environment, but defects such as film floating occur in a high temperature and high humidity environment. This is considered to be because the adhesion between the reflective layer and the resin substrate is weak when the adhesion layer is composed of only one layer of OH-10.

  In Comparative Examples 7 to 10, in order to improve the adhesion between the reflective layer and the resin substrate, OH-10 of the adhesion layer is the second layer, and the first layer is between the resin substrate and the second layer. A layer is provided. However, when the first layer of the adhesion layer is composed of aluminum oxide, zirconium oxide, yttrium oxide or silicon dioxide, the effect of improving adhesion under an environmental test (especially a moisture resistance test and a light resistance test) is obtained. Not.

  On the other hand, in Examples 1-8, the 1st layer 2a of the adhesion layer 2 is comprised with the cerium oxide film | membrane, and durability (humidity resistance) and adhesiveness in a high-temperature, high-humidity environment improve significantly. ing. That is, it can be said that the fact that the first layer 2a of the adhesion layer 2 is a cerium oxide film has a remarkable effect in improving durability and adhesion in a high temperature and high humidity environment.

  In Comparative Example 11, silicon dioxide is used as the second layer in order to improve the heat resistance performance, but the adhesion with OH-10 is insufficient. In Comparative Examples 12 and 13, the adhesion layer was composed of three layers with the aim of further improving the adhesion of the reflective layer. However, although the adhesion was improved, cracking in a high temperature environment could not be prevented.

  On the other hand, as in Examples 1 to 8, if the adhesion layer 2 is composed of two layers and the second layer 2b made of OH-10 is formed on the first layer 2a made of the cerium oxide film, By comparing with Comparative Examples 12 and 13, it can be said that the effect of reducing the occurrence of cracks in a high temperature environment can be demonstrated, and by comparing with Comparative Examples 7 and 8, the adhesion strength of the reflective layer in a high temperature and high humidity environment is reduced. It can be said that the effect of simultaneously suppressing the generation of cracks in a high temperature environment and the decrease in the adhesion of the reflective layer due to ultraviolet rays is exhibited.

  Moreover, when neither an cerium oxide film nor OH-10 is included in the adhesion layer as in Comparative Examples 1 to 3, an average reflectance of 90% or more in the visible light region cannot be ensured. Here, FIG. 7 shows the change in the reflectance with respect to the wavelength before and after each test in the reflector of Example 1, and the change in the reflectance with respect to the wavelength after the moisture resistance test in the reflector in Comparative Example 1. Show. As shown in the figure, in Example 1, even after any of the heat resistance test, the moisture resistance test, and the light resistance test, the reflectivity is hardly lowered from that before the test (initial stage). In the visible light region of 420 nm to 700 nm, an average reflectance of 90% or more can be secured, but in Comparative Example 1, after the moisture resistance test, an average reflectance of 90% or more cannot be secured in the visible light region. It is known that the changes in reflectance in the other Examples 2 to 8 show the same change as in Example 1.

  From the above, it can be said that according to the film configuration of the present invention, it is possible to realize a highly durable reflecting mirror that has all of moisture resistance, heat resistance and light resistance. And it can be said that functional deterioration such as mechanical deterioration such as film peeling and cracking and a decrease in reflectance can be suppressed even under severe conditions such as in-vehicle use. In particular, the first layer 2a of the adhesion layer 2 is composed of a cerium oxide film, the second layer 2b is composed of OH-10, and the reflective layer 3 and the dielectric layer are formed on the adhesion layer 2 composed of these two layers. It can be concluded that the configuration in which 4 is formed in order is the most preferable configuration capable of maintaining performance in both a high temperature and high humidity environment and a high temperature environment.

  INDUSTRIAL APPLICABILITY The present invention is used for reflectors that are used in harsh environments, such as in-vehicle applications, which require all of moisture resistance, heat resistance, and light resistance, such as reflection mirrors for illumination optical systems of room mirrors and head-up displays. Is possible.

DESCRIPTION OF SYMBOLS 1 Resin substrate 2 Adhesion layer 2a 1st layer 2b 2nd layer 3 Reflective layer 4 Dielectric layer 4a 1st low refractive index layer 4b High refractive index layer 4c 2nd low refractive index layer

Claims (2)

On the resin substrate, an adhesion layer, a reflective layer made of an aluminum film, and a dielectric layer are laminated in this order,
The adhesion layer is composed of two layers, and the first layer and the second layer are laminated in this order from the resin substrate side,
The first layer is composed of a cerium oxide film,
The aluminum surface reflecting mirror, wherein the second layer is formed of a layer made of a mixture of titanium oxide and praseodymium oxide. The dielectric layer is composed of a dielectric multilayer film in which a low refractive index layer and a high refractive index layer are laminated,
The low refractive index layer is composed of a layer containing silicon dioxide,
2. The aluminum surface reflecting mirror according to claim 1, wherein the high refractive index layer is formed of any one of a layer containing titanium oxide, a layer made of zirconium oxide, and a layer made of tantalum oxide.

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