JP2021162695A - Reflector and method for producing the same - Google Patents

Abstract

To provide a reflector that can prevent pin holes of a reflection layer from increasing with time without complicating a protective layer to be formed on a reflection film.SOLUTION: A reflector has a base material having reflection layers and protective layers laminated thereon, where, at least two or more protective layers are continuously laminated, made of the same material.SELECTED DRAWING: None

Description

The present invention relates to a reflective material and a method for producing the same. Specifically, the present invention relates to a reflective material used in a projector and an optical device and a method for manufacturing the same.

Conventionally, in a projector or an optical device, a metal film is formed on the surface of a resin base material on a mirror or the like that reflects an image and is projected onto a projection surface, and the metal film is covered with a dielectric film to protect the metal film. The product is being manufactured. As the reflective members such as these mirrors, those in which thin films are laminated by using a vapor deposition apparatus are used, and an apparatus for forming the thin films is also proposed.

Patent Document 1 includes a step of heating a resin work to a temperature equal to or lower than the softening temperature of the resin constituting the work, and can improve the reflectance of the metal thin film even when sputtering is performed at high speed. The film forming method and the film forming apparatus are described.

Patent Document 2 relates to a method of vapor-depositing a protective film for a light emitting element, wherein a first protective film of silicon nitride is vapor-deposited at a predetermined film thickness ratio, and then a second protective film of silicon oxide is vapor-deposited. Therefore, a method is described in which a protective film having a low water permeation amount similar to the conventional one but having a thickness significantly thinner than that of the conventional protective film can be vapor-deposited.

JP-A-2017-82291 Special Table 2019-512874

However, Patent Document 1 describes an apparatus and process for forming a reflective member, and a film forming method for improving reflectance, but describes reducing pinholes generated over time in the reflective layer. Not.
Further, Patent Document 2 describes that a protective layer is laminated on the light emitting element in order to protect the light emitting element, but does not describe that the protective layer suppresses the occurrence of pinholes. Further, there is a problem that the reflection characteristics are changed by laminating different kinds of films, and the degree of freedom in designing the thickness of the films is reduced.

Therefore, it is an object of the present invention to provide a reflective material capable of suppressing an increase in pinholes of the reflective layer over time without complicating the protective layer formed on the reflective film.

As a result of diligent studies to solve the above problems, the present inventors have completed the following inventions.
The first aspect of the present invention is a reflective material in which a reflective layer and a protective layer are laminated on a base material, in which at least two or more protective layers are continuously laminated on the same material.

In the first invention, the number of pinholes measured by the following method per ^{100 cm 2} of the reflective material after being stored in a constant temperature and humidity chamber at 85 ° C. and 85% for 1000 hours is preferably 200 or less. ..
<Pinhole measurement method>
The reflector was placed on the surface light source with the protective layer facing up, a luminance meter was installed at a position 45 cm away from the reflector, and the measured value of the luminance was measured by two-dimensional data analysis.

In the first invention, it is preferable that the protective layer is a silicon oxide thin film.

In the first invention, the total film thickness of the protective layer is preferably 15 nm or more and 50 nm or less.

In the first invention, it is preferable that the protective layer is formed by a chemical vapor deposition method.

In the first invention, it is preferable that the reflective layer is an aluminum film.

In the first invention, it is preferable that the reflective layer is formed by a sputtering method.

In the first invention, it is preferable that the base material is made of resin.

The first reflective material of the present invention is preferably used for automobiles.

The first reflective material of the present invention is preferably for a head-up display.

The second invention is a method for producing a reflective material in which a reflective layer and a protective layer are sequentially formed on a resin base material, wherein the protective layer is a first protective layer and a second protective layer. An installation step of providing a protective layer and installing a resin base material in the chamber, a depressurizing step of reducing the pressure in the chamber, a reflective layer film forming step of forming the reflective layer by sputtering, and the first protective layer. At least a first protective layer film forming step for forming a film by a plasma CVD method and a second protective layer forming step for forming the second protective layer on the first protective layer by a plasma CVD method are provided. This is a method for producing a reflective material, wherein after the first protective layer film forming step, the second protective layer film forming step is performed without opening the chamber to the atmosphere.

The reflective material of the present invention suppresses the increase of pinholes with time, can extend the life of the reflective material while maintaining the reflective characteristics, and has high industrial value. Further, according to the method for producing a reflective material of the present invention, it is possible to produce the reflective material of the present invention without adding a special process.

(A) shows the layer structure of the reflector of Examples 1 and 2, (b) shows the layer structure of the reflector of Comparative Example 1, and (c) shows the layer structure of the reflector of Comparative Example 2. (D) shows the layer structure of the reflective material of Comparative Example 3, and (e) shows the layer structure of the reflective material of Comparative Example 4.

Next, the present invention will be specifically described based on an example of the embodiment of the present invention, but the present invention is not limited to the embodiment described below.

<Reflective material>
The reflective material of the present invention has a structure in which a film of a reflective layer and a protective layer is laminated on the surface of a base material, and the protective layer is made of the same material and at least two or more layers are continuously laminated. As described below, the base material is preferably a resin base material, the reflective layer is preferably a metal film such as an aluminum film, and the protective layer is preferably a thin film composed of silicon oxide. Further, the adhesion improving layer may be formed between the base material and the reflective layer.

In the present invention, the protective film is formed by forming the same film multiple times without breaking the vacuum. As a result, it is possible to effectively reduce the intrusion of water vapor and the like from the outside as compared with the case of forming a film at one time, and effectively suppress the occurrence of pinholes in the reflective layer over time due to oxidation or the like. can do.

Pinholes occur due to various causes, but the pinholes that increase over time become transparent because the metal of the reflective layer changes to oxides, etc. due to the intrusion of water, oxygen, etc. from the outside of the reflective material. It is thought that it occurs when the film becomes thin or the film is reduced.

In the present invention, during the non-deposition time between the film formation of the plurality of protective layers and the film formation, the very thin layer on the surface is slightly oxidized and changed to change the surface state, and different types of films are laminated. The same effect as is obtained, and contributes to the improvement of barrier properties such as water and oxygen.
In addition, since the amount of oxygen is low during the non-deposition period, the thickness of the layer affected by oxidation is extremely thin, and since a film under the same conditions is formed, it functions even though it is a plurality of layers. In terms of surface, it can be regarded as one layer as a whole.
Since it is difficult for a thin film to exhibit its function unless it has a certain thickness, when laminating different types of films, it is necessary to make each film a certain thickness, and it is difficult to reduce the overall film thickness. Is.
On the other hand, in the present invention, since the layer affected by the oxidation between the films is extremely thin, the overall thickness can be reduced while obtaining the effect of stacking the layers, and the outside of the reflector can be reduced. It is considered that the increase in pinholes over time due to the influence of the film could be reduced and the decrease in reflectance due to the increase in film thickness could be prevented.

In addition, the presence of an ultra-thin oxide layer between layers stops the growth of layer defects (when there is a film defect, for example, a foreign substance), and the ultra-thin oxide layer stops the growth of a new layer. Can be uniformly formed. Further, even if there are pinholes in each layer, the positions are displaced, so that pinhole defects can be suppressed even if each layer is thin.

Further, when the same type of film is formed multiple times, the conditions at the time of forming the film are not changed and there is no need to add an apparatus, etc., as compared with the case where different types of films are laminated, so that the film forming is easily performed. be able to. Further, as compared with the single protective layer, the protective layer of the present invention composed of a plurality of layers can obtain an effect even if the overall film thickness is a thin film, so that the reflection characteristics such as reflectance can be improved. You can expect it.

From the above effects, in the present invention, it is possible to easily and easily suppress an increase in pinholes over time by laminating a plurality of layers of the same material without laminating different films as a protective layer. Become.

The fact that the protective layers are laminated "at least two or more layers of the same material" means that there is a non-deposited time between the layers in the film forming process of the protective layer.
Also, the fact that the protective layers are "continuously" laminated means that there is no layer made of another material between the layers made of the same material. In the above, it was stated that during the non-deposition time between layers, the very thin layer on the surface of the protective layer is slightly oxidized and changes, and the surface state changes. Even if there is a very small amount of a very thin oxide layer, it is interpreted as continuous.

(Base material)
The base material used for the reflective material of the present invention is not particularly limited, and may be a film, a sheet, or a molded product, and is not particularly limited as long as it is a base material capable of forming a film on the surface.
As the base material of the present invention, a resin base material is preferable, and a resin molded body is more preferable.

The material used as the base material may be any material such as resin or glass that can form a film on the surface, and the material is not limited. Further, the base material may have a multi-layer structure in which two or more kinds of materials are laminated.

When a resin is used as the base material, for example, polyethylene terephthalate resin (PET), polyethylene terephthalate-based copolymer resin (copolymer resin using cyclohexanedimethanol or the like as the alcohol component of polyester instead of ethylene glycol). Etc.), Polybutylene terephthalate resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin (PP), cycloolefin copolymer resin (COC, cyclic olefin copolymer), cycloolefin polymer resin (COP), ionomer resin, poly-4 -Methylpentene-1 resin, polymethylmethacrylate resin, polystyrene resin, ethylene-vinyl alcohol copolymer resin, acrylonitrile resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polyamideimide resin, polyacetal resin, polycarbonate resin ( PC), polysulfone resin, ethylene tetrafluoride resin, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin and the like, and among these, polycarbonate resin (PC) is preferable in terms of versatility and moldability.

The size of the base material varies depending on the use of the reflective material and is not particularly limited. The thickness of the base material is preferably 1 to 10 mm from the viewpoint of imparting a predetermined strength to the reflective material.

(Adhesion improvement layer)
In the reflective material of the present invention, there may be an adhesion improving layer between the base material and the reflective layer to reduce peeling of the reflective layer. The adhesion improving layer is not limited to the film-formed layer, and may be a surface-treated base material such as plasma treatment. Further, depending on the material of the base material and the reflective layer, it is possible to omit the adhesion improving layer when the adhesion improving force can be obtained without a practical problem even if the adhesion improving layer is not provided.

When forming the adhesion improving layer, a thin film such as silicon oxide is preferable, but the material, film thickness, and manufacturing method are not limited. For example, in consideration of simplification of the manufacturing process, it is preferable to form a film with the same raw material and the same method as the film used for the protective layer. As a film forming method, either a physical vapor deposition method (PVD) or a chemical vapor deposition method (CVD) is possible, but the plasma CVD method, which is a film forming method using plasma, is desirable. Further, it may be formed by coating with a wet coat regardless of PVD and CVD.

The film thickness of the adhesion improving layer is preferably 8 nm or more and 15 nm or less, and more preferably 9 nm or more and 13 nm or less. If it is 8 nm or more, it can be formed as a film, and if it is 15 nm or less, the heat load at the time of forming a film can be reduced.

When processing other than film formation, a particular method such as corona treatment, plasma treatment, flame treatment, etc. is not selected. Further, the treatment may be performed in a process different from that of the apparatus for forming the reflective layer.

<Reflective layer>
Deposition of metal elements is desirable as the reflective layer. Aluminum, silver, gold, copper, nickel, platinum, or any other material exhibiting reflective characteristics may be used, and is not limited, but aluminum is preferable from the viewpoint of reflective performance and price. The film forming method is not particularly limited, but any method such as vacuum heating vapor deposition, electron beam beam deposition, ion plating, and sputtering method can be applied. From the viewpoint of handling of raw materials and reflection performance, film formation by the sputtering method is desirable.

The film thickness of the reflective layer is not particularly limited, but is preferably 90 nm or more, more preferably 100 nm or more, and further preferably 110 nm or more in order to prevent a decrease in reflectance due to light transmission. .. When the film forming time is long, a heat load is applied, so that the base material may be deformed. Therefore, 500 nm or less is preferable, 400 nm or less is more preferable, and 300 nm or less is further preferable.

<Protective layer>
As the protective layer, an inorganic-containing thin film such as silicon oxide is preferable when forming a film, but the material, film thickness, and manufacturing method are not particularly limited. For example, in consideration of simplification of the manufacturing process, when the adhesion improving layer is provided, it is preferable to use a film used for the adhesion improving layer and a film capable of forming a film by the same raw material and the same method.
As the inorganic-containing thin film, at least one selected from the group consisting of silicon oxide, silicon nitride, silicon nitride, silicon oxide, silicon oxide nitride, aluminum oxide, aluminum nitride, aluminum nitride and aluminum oxide, and silicon carbide. A thin film containing an inorganic compound is preferable. Further, as the metal oxide or the metal nitride, those obtained by plasma decomposition of an organic compound may be used. From the viewpoint of protective properties and transparency, metal oxide-based films such as silicon oxide and aluminum oxide are preferable, and silicon oxide is particularly preferable.

When the protective layer is formed by the plasma CVD method, as a raw material for forming a silicon oxide thin film, a silicon compound can be used in any state of gas, liquid, or solid under normal temperature and pressure. .. In the case of gas, it can be introduced into the discharge space as it is. In the case of liquid or solid, it can be vaporized by means such as heating, bubbling, depressurization, and ultrasonic irradiation. Further, the solvent may be diluted before use, and the solvent may be an organic solvent such as methanol, ethanol or n-hexane, or a mixed solvent thereof.

Examples of the silicon compound include silane, tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetrat-butoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and diethyldimethoxy. Silane, diphenyldimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltriethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, hexamethyldisiloxane (HMDSO), bis (dimethylamino) dimethyl Silane, bis (dimethylamino) methylvinylsilane, bis (ethylamino) dimethylsilane, N, O-bis (trimethylsilyl) acetamido, bis (trimethylsilyl) carbodiimide, diethylaminotrimethylsilane, dimethylaminodimethylsilane, hexamethyldisilazane, hexamethyl Cyclotrisilazane, heptamethyldisilazane, nonamethyltrisilazane, octamethylcyclotetrasilazane, tetrakis (dimethylamino) silane, tetraisocyanatosilane, tetramethyldisilazane, tris (dimethylamino) silane, triethoxyfluorosilane, allyl Dimethylsilane, allyltrimethylsilane, benzyltrimethylsilane, bis (trimethylsilyl) acetylene, 1,4-bistrimethylsilyl-1,3-butadiine, di-t-butylsilane, 1,3-disilabtan, bis (trimethylsilyl) methane, cyclopenta Dienyltrimethylsilane, phenyldimethylsilane, phenyltrimethylsilane, propargyltrimethylsilane, tetramethylsilane, trimethylsilylacetylene, 1- (trimethylsilyl) -1-propine, tris (trimethylsilyl) methane, tris (trimethylsilyl) silane, vinyltrimethylsilane, Examples thereof include hexamethyldisilane, octamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, hexamethyldisiloxane, hexamethylcyclotetrasiloxane, and methylsilicate (for example, "Methylsilicate 51" manufactured by Corcote Co., Ltd.).

The protective layer needs to be formed in a plurality of times under the same conditions. However, in this case, it is preferable not to break the vacuum between the film formations.

If the thickness of the protective layer is too thick, it has the effect of suppressing an increase in pinholes over time, but it causes a decrease in reflectance. Further, if it is too thin, the function as a film cannot be obtained, so that it does not contribute to the suppression of the increase of pinholes with time.
The thickness of each single layer of the protective layer composed of a plurality of layers is preferably 8 nm or more and 15 nm or less, and more preferably 9 nm or more and 13 nm or less. If the single layer film thickness of the protective layer is 8 nm or more, it can be formed as a film. If it is 15 nm or less, the heat load at the time of film formation can be reduced.
The total thickness of the entire protective layer is preferably 16 nm or more and 50 nm or less, more preferably 17 nm or more and 40 nm or less, and further preferably 19 nm or more and 30 nm or less. If the total thickness of the entire protective layer is 16 nm or more, it functions as a protective layer. If it is 50 nm or less, it does not cause deterioration of optical characteristics.

<Characteristics of reflector>
(Pinhole resistance)
The reflective material of the present invention has pinhole resistance, and the ^{number of pinholes per 100 cm 2} of the reflective material after film formation (the number of pinholes after film formation) is preferably 10 or less, and 5 pieces. The following is more preferable, and 0 is further preferable.
^{The number of pinholes per 100 cm 2} of the reflective material (the number of pinholes after storage) after storage in a constant temperature and humidity chamber at 85 ° C. and 85% for 1000 hours is preferably 300 or less, preferably 250 or less. More preferably, the number is more preferably 200 or less, and particularly preferably 150 or less.
The pinhole measurement method is performed by arranging the reflector on the surface light source with the protective layer facing up, installing a luminance meter at a position 45 cm away from the reflector, and analyzing the measured brightness by two-dimensional data analysis. rice field.

<Manufacturing method of reflective material>
The method for producing a reflective material of the present invention is a method for producing a reflective material in which a reflective layer and a protective layer are formed in order on a resin base material, and the protective layer is a first protective layer. With a second protective layer
Installation process of installing a resin base material in the chamber,
A decompression step of depressurizing the inside of the chamber,
A reflective layer film forming step of forming the reflective layer by sputtering,
A first protective layer film forming step of forming the first protective layer by a plasma CVD method, and
A second protective layer film forming step of forming the second protective layer on the first protective layer by a plasma CVD method is provided at least.
After the first protective layer film forming step, the second protective layer film forming step is performed without opening the chamber to the atmosphere.

In the method for producing a reflective material of the present invention, an adhesion improving layer forming step of forming an adhesion improving layer on the surface of a base material may be provided before the reflective layer forming step.

When installing a resin base material in a chamber, in order to prevent moisture from adhering to the surface of the base material, the resin base material is injection-molded and then immediately installed in the chamber to start film formation. Is preferable.

In the depressurizing step, the pressure is preferably reduced to 10 Pa or less, more preferably 5 Pa or less, and further preferably 1 Pa or less. As the inert gas to be introduced, xenon, argon, neon, helium and the like can be used, and among them, argon having a large atomic weight is more preferable from the viewpoint of economy and sputter yield.

In the above description, the form of forming the two protective layers of the first protective layer and the second protective layer has been described, but as long as the protective layer is two or more layers, the number of layers is not particularly limited and each protection is provided. The film may be formed between the layers without opening the chamber to the atmosphere.

As a film forming apparatus for producing a reflective material, the reflective layer and the protective layer can be formed on the base material without being released to the atmosphere (preferably, the base material and the reflective layer are further adhered to each other). A device capable of forming a plurality of films in one film forming chamber is preferable (so that an improved layer can be formed). However, it is also possible to form a film using a plurality of devices in which a plurality of chambers can be connected without opening to the atmosphere.

<Use of reflective material>
The reflective material of the present invention can be suitably used for in-vehicle use, and above all, it can be suitably used as a reflective material for a head-up display. The reflective material of the present invention can suppress an increase in pinholes over time, and can extend the life of the reflective material for a long period of time, even when used for in-vehicle use, which can be in a harsh condition where the temperature becomes high.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.

<Film formation equipment>
The reflective material was produced using a high-speed sputtering film forming apparatus. This device is equipped with a plasma CVD chamber and a sputtering film formation chamber, and the work mounting portion on which the substrate is placed moves between the two film formation chambers, so that the adhesion improving layer is not opened to the atmosphere. It is possible to form a reflective layer and a protective layer.

<Film formation method>
After preparing the reflective material and opening it to the atmosphere, the base material was placed on the work mounting portion and vacuum exhaust was performed. After reducing the pressure to 0.5 Pa, the work mounting portion is moved to the plasma CVD chamber when the adhesion improving layer and the protective layer are formed, and to the sputtering film forming chamber when the reflective layer is formed. Gas was introduced to generate plasma, and film formation was carried out. After the film was formed, the apparatus was opened to the atmosphere, and then a sample was taken out from the work mounting portion.

(Base material)
A polycarbonate molded product was used as a base material constituting the reflective material. The size of the molded product is 145 mm × 58 mm × 5 mm. After molding the base material by injection molding, the base material was immediately placed on the work mounting portion of the film forming apparatus to perform the following film forming treatment.

(Adhesion improvement layer)
The vacuum device in which the base material was inserted was exhausted to 0.5 Pa. Then, argon (Ar) was supplied at 100 sccm and hexamethyldisiloxane (HMDSO) was supplied at 5 sccm at the same time, and when the pressure became constant, the RF power was set to 800 W, and discharge and film formation were carried out. The film formation time was 60 seconds.

(Reflective layer)
After film formation of the adhesion improving layer, the work mounting portion was moved to the sputtering film formation chamber. Ar was introduced by 270 sccm, and when the pressure became constant, the DC power was set to 35 kW and the Al target was sputtered to form a reflective layer. The film formation time was 8 seconds.

(Protective layer)
After the reflective layer was formed, the work mounting portion was moved to the plasma CVD chamber in which the adhesion improving layer was formed. Then, only HMDSO was supplied in an amount of 60 sccm, and when the pressure became constant, the RF power was set to 500 W, and discharge and film formation were carried out. The film formation time and the number of film formations were changed so as to obtain the predetermined film thickness shown in Table 1.

<Evaluation of reflective material>
(Pinhole)
The pinholes after film formation (the number of pinholes after film formation) were measured by the following method. After the measurement, the reflective material was stored in a constant temperature and humidity chamber at 85 ° C. and 85%, and 1000 hours later, the number of pinholes of the same sample was measured (the number of pinholes after storage) to evaluate the increase in pinholes. ..
To evaluate pinholes, a surface light source (Treviewer A4-500, manufactured by Tri-Tech Co., Ltd.) that emits uniform light intensity is placed horizontally, and a reflector sample prepared on it is placed with the protective layer side facing up. A lens of a luminance meter (manufactured by Konica Minolta Co., Ltd., model: CA-2000) was installed at a position 45 cm away from the surface of the reflector sample on the side opposite to the surface light source side, and the luminance was measured. The two-dimensional data of the obtained brightness measurement values (x and y are the film coordinates, z is the absolute value of the brightness) are analyzed, and the brightness value is a constant threshold value (1 or more when the brightness is 100 at the brightest point). Those exceeding) were counted.

(Evaluation of film thickness)
When the base material was formed, the silicon wafer was placed next to the base material, and the same film as the reflective material was formed on the silicon wafer. After the film formation, the total film thickness deposited on the silicon wafer taken out was measured using a high-precision fine shape measuring instrument (manufactured by Kosaka Laboratory Co., Ltd., product name "Surfcoder ET4000A"). Further, the film thickness of each layer was measured by forming a single-layer film of each layer by the same method and using the same high-precision fine shape measuring instrument.

Reflective materials of each Example and each Comparative Example were prepared according to the above-mentioned film forming method, and evaluated according to the above-mentioned evaluation method. Table 1 shows the film thicknesses of each Example and each Comparative Example, and the evaluation results. Further, FIG. 1 (a) shows the layer structure of the reflective material of Examples 1 and 2, FIG. 1 (b) shows the layer structure of the reflective material of Comparative Example 1, and FIG. 1 (c) shows the layer structure of the reflective material. 1 (d) shows the layer structure of the reflective material of Comparative Example 3, and FIG. 1 (e) shows the layer structure of the reflective material of Comparative Example 4. The thickness of each layer in the figure does not indicate an accurate ratio of each layer thickness.
<Example 1>
Adhesion improving layer and reflective layer are formed on a polycarbonate base material under the above method and conditions, protective layer 1 is formed with a film thickness of 10 nm, discharge is stopped once, and protective layer 2 is provided with the same gas flow rate and RF power. A 10 nm film was formed.

<Example 2>
A film was formed in the same manner as in Example 1 except that the thickness of the protective layer 2 was 11 nm.

<Comparative example 1>
A 20 nm protective layer was formed in the same manner as in Example 1 except that one layer was formed.

<Comparative example 2>
In Comparative Example 1, a film was formed in the same manner as in Comparative Example 1 except that the thickness of the protective layer was 60 nm.

<Comparative example 3>
In Comparative Example 1, a film was formed in the same manner as in Comparative Example 1 except that the thickness of the protective layer was 10 nm.

<Comparative example 4>
In Comparative Example 3, the thickness of the reflective layer was set to 60 nm, and after the film formation was completed, the work mounting portion was moved to the plasma CVD chamber, and the thickness of the protective layer 1 was set to 10 nm. Then, it was moved to a sputtering film formation chamber, and the same insertion layer as the reflection layer was formed with a thickness of 60 nm. Next, the work mounting portion was moved to the plasma CVD chamber, and the protective layer 2 was formed again with a thickness of 10 nm.

<Discussion>
When Example 1 and Comparative Example 1 are compared, the number of pinholes in Example 1 in which the same protective layer is formed by dividing the film thickness into two times is about 1/2, which is the same film thickness. The increase was suppressed.
In Example 2, the thickness of the protective layer for the second time was increased, but by increasing the thickness of the protective layer, further suppression of the increase in pinholes was observed. There are various possible causes for the increase in pinholes, one of which is that the metal in the reflective layer forms a transparent oxide due to the intrusion of water and oxygen from the surface of the reflective material, and light escapes. Be done. Therefore, when the protective layer is formed, the film is not formed at once, but is formed in multiple times, so that cracks at the time of film formation and pinholes of the protective layer are canceled, resulting in the result. It is considered that the barrier performance was improved and the increase of pinholes over time was suppressed.

Further, in Comparative Example 2, the effect of suppressing the increase in pinholes is seen by increasing the film thickness of the protective layer, but as the film thickness increases, the reflectance decreases due to light absorption and the like. When high reflectance is desired, it is necessary to suppress the increase in pinholes while forming a thin film as in Examples 1 and 2.

In Comparative Example 3, the protective layer was thinned to 10 nm, but when the film thickness was thin, it is considered that the function as a film could not be sufficiently exhibited and the increase in pinholes could not be suppressed.
In Comparative Example 4, the protective layer was positively divided to form a film. That is, the protective layer cannot be continuously formed of the same material, and the insertion layer is formed between the two protective layers. In this case, pinholes are increasing even though the number of protective layers is three. It is considered that this is because, as shown in Comparative Example 3, since the film thickness of each silicon oxide film is thin, the function as a protective film is not sufficiently exhibited, and the reflective layer forms a compound, which leads to an increase in pinholes. Be done.

From the above, according to the reflective material of the present invention and the method for producing the same, it is possible to suppress an increase in pinholes after film formation while maintaining a high reflectance, and an increase in pinholes while keeping the thickness of the protective layer thin. It is useful because it has an inhibitory effect.

Since the reflective material of the present invention can suppress an increase in pinholes over time, the reflective material can be used for a long period of time, and is therefore industrially useful.

Claims (11)

In a reflective material in which a reflective layer and a protective layer are laminated on a base material,
A reflective material in which at least two or more protective layers are continuously laminated with the same material. The reflector according to claim 1, wherein the number of pinholes measured by the following method per ^{100 cm 2} of the reflector after being stored in a constant temperature and humidity chamber at 85 ° C. and 85% for 1000 hours is 200 or less.
Pinhole measurement method: The reflector was placed on the surface light source with the protective layer facing up, a luminance meter was installed at a position 45 cm away from the reflector, and the measured luminance was measured by two-dimensional data analysis. .. The reflective material according to claim 1 or 2, wherein the protective layer is a silicon oxide thin film. The reflective material according to any one of claims 1 to 3, wherein the total film thickness of the protective layer is 15 nm or more and 50 nm or less. The reflective material according to any one of claims 1 to 4, wherein the protective layer is formed by a chemical vapor deposition method. The reflective material according to any one of claims 1 to 5, wherein the reflective layer is an aluminum film. The reflective material according to any one of claims 1 to 6, wherein the reflective layer is formed by a sputtering method. The reflective material according to any one of claims 1 to 7, wherein the base material is made of resin. The reflective material according to any one of claims 1 to 8, which is used for an automobile. The reflective material according to claim 9, which is for a head-up display. A method for manufacturing a reflective material in which a reflective layer and a protective layer are formed in order on a resin base material.
The protective layer includes a first protective layer and a second protective layer.
Installation process of installing a resin base material in the chamber,
A decompression step of depressurizing the inside of the chamber,
A reflective layer film forming step of forming the reflective layer by sputtering,
A first protective layer film forming step of forming the first protective layer by a plasma CVD method, and
A second protective layer film forming step of forming the second protective layer on the first protective layer by a plasma CVD method is provided at least.
A method for producing a reflective material, wherein after the first protective layer film forming step, the second protective layer film forming step is performed without opening the chamber to the atmosphere.

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