JP3335599B2 - Heat shielding film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat ray shielding film having excellent moisture resistance.

[0002]

2. Description of the Related Art An oxide film, an Ag film, a three-layer film in which an oxide film is sequentially laminated on a substrate surface, or an oxide film, Ag
A film composed of (2n + 1) layers (n ≧ 1), such as a film composed of five layers in which a film, an oxide film, an Ag film, and an oxide film are sequentially laminated,
This is a heat ray blocking film called a Low-E (Low-Emissivity) film, and the glass on which the Low-E film is formed is called a Low-E glass.

[0003] Low-E glass is a functional glass that can prevent a temperature drop in a room by reflecting heat rays from the room, and is mainly used in cold regions for the purpose of reducing a heating load. It also has the effect of blocking solar heat, so that it is also used in automotive window glass. Since it is transparent and shows conductivity, it is also used as an electromagnetic shielding glass. If an electric heating means such as a bus bar made of a conductive print or the like is provided, it can be used as an electrically heated glass.

[0004] The main Low-E glass is ZnO.
/ Ag / ZnO / glass. However, such a film lacks durability such as abrasion resistance and chemical stability, so that it cannot be used as a single plate and needs to be laminated glass or double glazing. In particular, there is a problem in moisture resistance, and white spots and white turbidity are generated due to humidity in the air and moisture contained in an interlayer film when laminated glass is used. For this reason, care has to be taken in storage and handling of veneers.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a heat ray shielding film having excellent moisture resistance.

[0006]

According to the present invention, an oxide film, a metal film, and an oxide film are alternately laminated on a substrate (2n +
1) In the heat ray blocking film composed of layers (n ≧ 1), when viewed from the substrate, the oxide film (B) formed on the metal film (A) mainly composed of Ag which is farthest from the substrate is Sn. The present invention provides a heat ray shielding film including at least one zinc oxide film having a content of 1 to 4 atomic% with respect to the total amount of Zn. The oxide film (B) is a film formed on the metal film (A) farthest from the substrate when viewed from the substrate (the side opposite to the substrate side of the metal film (A)), and has a Sn content. Is 1 to the total amount with Zn
This is a film including at least one ZnO film of 4 atomic% (Sn is doped with 1 to 4 atomic% with respect to the total amount of Zn).

Hereinafter, the oxide film (B) according to the present invention will be described. As described above, in the case of the conventional Low-E glass (film composition: ZnO / Ag / ZnO / glass), when left in a single plate indoors, white spots and white turbidity occur due to moisture in the air. By observing the film having white spots and opacity with a scanning electron microscope (SEM), the presence of cracks and wrinkles on the surface of the film and the presence of peeling of the film were confirmed.

[0008] Regarding the peeled portion of this film, Ag and Zn
Elemental analysis was performed for each of the elements. Ag was present in a substantially constant amount regardless of the presence or absence of peeling.
In the case of n, the detection amount was almost halved at the peeled portion. That is,
It was found that the peeling occurred at the interface between the uppermost ZnO layer and the Ag layer.

Next, a moisture resistance test (50 ° C., 95% relative humidity)
Samples before and after standing in an atmosphere for 6 days) were examined by X-ray diffraction using CuKα radiation. For the (002) diffraction line of hexagonal ZnO and the (111) diffraction line of cubic Ag, the diffraction angle is 2
Table 1 shows θ (the center of gravity of the peak), the crystal plane distance d, and the integral width IW.

The degree of lattice distortion due to internal stress can be detected from the degree of peak shift in the X-ray diffraction method. ZnO
In the case of the sample of (b) / Ag / ZnO (a) / glass, the peak of ZnO (b) in the uppermost layer is ZnO (b).
Since the peak is detected at 5 to 15 times the intensity of the peak according to (a), the peak of ZnO in the whole sample by the X-ray diffraction method is as follows:
Although there may be some influence by ZnO (a), it can be considered that the peak is almost due to hexagonal ZnO (b) in the uppermost layer.

[0011]

[Table 1]

According to Table 1, the (002) diffraction line of ZnO of the Low-E film before the humidity resistance test was 2θ = 3 of ZnO powder.
The position is considerably shifted as compared with 4.44 ° . This suggests the presence of crystal strain. This crystal strain is considered to be due to the internal stress of the film. In the sample before the moisture resistance test, the crystal plane distance d = 2.650 °, and Zn
It is 1.8% larger than d = 2.602 ° of the O powder. This indicates that the crystal has received a fairly large compressive stress. In the sample after the moisture resistance test, d =
2.641 °, and the crystal strain is slightly reduced. This corresponds to the fact that the internal stress of the hexagonal ZnO in the uppermost layer was partially relaxed by cracks, wrinkles, and peeling.

Regarding the (111) diffraction line of Ag, since the integration width IW after the moisture resistance test is small, it is considered that the Ag undergoes grain growth by performing the moisture resistance test.

That is, the mechanism of white turbidity is that the uppermost ZnO film cannot withstand the internal stress, and peels and breaks from the interface with the Ag film, and then the silver deteriorates, that is, the grain size increases, and this breakage occurs. It is considered that the light is scattered by the scratched surface and the large silver particles, and appears turbid. In the example of Table 1,
The internal stress is a compressive stress, and there are two types of internal stress, a compressive stress and a tensile stress, both of which cause film breakage.

From the above, it can be seen that it is effective to reduce the internal stress of the uppermost ZnO film in order to suppress the clouding due to moisture.

In the present invention, it has been found that by doping Zn into ZnO, the internal stress can be reduced and the moisture resistance of the heat ray blocking film can be improved.

The internal stress of one layer (450 °) of the oxide film (B) and the glass / ZnO (450 °) / Ag (10
0 °) on the same oxide film (B) (450 °) as a heat ray blocking film formed by sputtering.
Table 2 shows the relationship between the diffraction angle 2θ (center of gravity position) of the (002) diffraction line and the moisture resistance of the heat ray blocking film.

[0018]

[Table 2]

The moisture resistance was evaluated by performing a test in which it was left in an atmosphere at 50 ° C. and a relative humidity of 95% for 6 days. The evaluation criteria were as follows: if there was no white turbidity near the edge of the film and no white spots with a diameter of 1 mm or more appeared, those where white turbidity appeared near the edge of the film or those where white spots with a diameter of 1 mm or more appeared Δ, when the cloudiness occurred on the entire surface of the film was evaluated as x. S
The doping amounts of n , Ca, and Ba are all 4% in atomic ratio with respect to the total amount with Zn.

According to Table 2, when Sn is doped into the ZnO film, the internal stress of the ZnO film is reduced. The moisture resistance of the heat ray blocking film using the ZnO film doped with these various elements is improved. In this case, the diffraction angle 2θ (center of gravity) of the (002) diffraction line of ZnO shifts to a higher angle side as compared with the non-doped one. This suggests that the crystal strain is smaller than that of the non-doped one, and supports that the internal stress of the film is small.

FIG. 1 is a sectional view of a typical example of the heat ray blocking film of the present invention. FIG. 1A is a cross-sectional view of a heat ray blocking film composed of three layers, and FIG. 1B is a cross-sectional view of a heat ray shielding film composed of (2n + 1) layers (n ≧ 1). Reference numeral 1 denotes a substrate, 2 denotes an oxide film, 3 denotes a metal film, and 4 denotes an oxide film (B) including at least one Sn- doped ZnO film.

As the substrate 1 in the present invention, besides a glass plate, a film or plate of plastic or the like can be used.

The oxide film (B) is made of Zn doped with Sn.
Contains at least one O film. If the doping amount of Sn is less than 1 atomic%, the internal stress does not decrease much, and the moisture resistance is not improved. Even if it exceeds 10 atomic%, the effect of reducing the internal stress does not change so much. Further, when the amount of addition is large, haze is likely to be generated due to moisture, and on the contrary, moisture resistance is deteriorated. Furthermore, as the amount of addition increases, the film formation rate decreases, and the productivity deteriorates. In consideration of the above, the optimal doping amount is 1 to 4 atomic% with respect to the total amount of Zn . Is preferably 2 atomic% or more, especially.

Regarding the ZnO film constituting the oxide film (B), as described above, the internal stress of hexagonal ZnO and the CuO
Diffraction angle 2θ by X-ray diffraction using Kα ray (center of gravity)
And almost correspond. The crystal system of the film mainly composed of ZnO is hexagonal. In order to improve the moisture resistance of the heat ray-shielding film of the present invention, the diffraction angle 2θ of the (002) diffraction line of hexagonal ZnO in X-ray diffraction using CuKα ray of the heat ray-shielding film.
It is preferable that the (center of gravity position) is a value between 33.88 ° and 35.00 °, particularly a value between 34.00 ° and 34.88 °. When the diffraction angle 2θ is 34.44 ° or less, the compressive stress is applied. When the diffraction angle 2θ is 34.44 ° or more, the tensile stress is applied.
Show.

The thickness of the oxide film (B) is not particularly limited, but is preferably 200 to 700 ° in consideration of the color tone and the visible light transmittance of the entire heat ray blocking film. The oxide film (B)
It may be a multilayer. For example, in the case where the heat ray blocking film of the present invention is placed inside and another substrate is laminated via a plastic intermediate film to form a laminated glass, the adhesion to the plastic intermediate film is adjusted or the durability is improved. Layer (the layer farthest from the substrate) in contact with the intermediate film for the purpose of
酸化 物 In some cases, the following oxide film (for example, a chromium oxide film), a film made of an oxide doped with another element, a composite oxide film, or the like is formed. It can also be configured.

When the oxide film (B) is formed by reactive sputtering in an oxygen-containing atmosphere, the metal film (A)
In order to prevent oxidation of the metal film, it is desirable to first form a thin metal film or a metal oxide film with insufficient oxidation on the metal film (A) in an atmosphere containing less oxygen. This thin metal film is oxidized during the formation of the oxide film (B) to become an oxide film. The preferable thickness of the oxide film (B) is a thickness including the thickness of the oxide film formed by oxidizing such a thin metal film.
In this specification, the same applies to an oxide film formed on the metal film 3.

The material of the oxide film 2 other than the oxide film (B) is not particularly limited. ZnO, SnO ₂ , TiO ₂ ,
A laminated film containing two or more of these materials, a film obtained by adding other elements to the film, or the like can be used. Further, considering productivity, any _{two of} a ZnO film, a SnO ₂ film, and a ZnO—SnO ₂ film are used. Of two or more layers alternately stacked, Si,
At least one of Ti, Cr, B, Mg, Sn, and Ga
Z total amount of seed is from 1 to 10 atomic%, relative to the total amount of the Zn
An nO film is preferred.

In consideration of the color tone and the visible light transmittance, the thickness of the oxide film 2 is desirably 200 to 700 °.
In the case of a laminated film, the total thickness may be 200 to 700 °, and the thickness of each layer is not limited.

Particularly, in the case of a heat ray blocking film having a five-layer structure of an oxide film, a metal film, an oxide film, a metal film, and an oxide film, or a film structure of five or more layers, the outermost oxide film (B ) Except for Si, Ti, Cr, B, Mg, Sn, G
a at least one of them is 1 to the total amount with Zn.
It is desirable that the film comprising at least one layer of ZnO film is 10 atomic%. In particular, it is preferably at most 6 atomic%.
It is particularly preferable that the content be 2 atomic% or more.
No.

The metal film 3 in the present invention is made of Ag
A film having a heat ray blocking performance such as a film or a film containing Ag as a main component containing at least one of Au, Cu, and Pd can be used. The metal film 3 may have a metal layer having various functions in addition to the metal film having the heat ray blocking performance. For example, it has a metal layer that adjusts the adhesive force between the metal film having the heat ray blocking performance and the oxide film (B) or the oxide film 2, or has a function of preventing metal diffusion from the metal film having the heat ray blocking performance. Examples include a metal layer. Examples of the metal constituting the metal layer having these functions include Zn,
Examples include Al, Cr, W, Ni, Ti, and alloys of two or more of these metals.

The thickness of the entire metal film 3 including these metal layers is suitably 50 to 150 °, particularly about 100 °, in consideration of the balance between the heat ray blocking performance and the visible light transmittance.

[0032]

[Action] oxide film at least a ZnO film containing the amount of Sn as (B) is from 1 to 10 atomic%, relative to the total amount of the Zn
By including the layer, the moisture resistance is remarkably improved as compared with the conventional heat ray shielding film. This is presumably because the oxide film (B) is less likely to be damaged due to the low internal stress of the oxide film (B), and deterioration due to moisture is suppressed.

[0033]

The EXAMPLES EXAMPLES dc sputtering on a glass substrate, Ar:
In an atmosphere of 2.0 × 10 ⁻³ Torr with O ₂ = 1: 9,
ZnSn containing 3.0 atomic% of Sn with respect to the total amount of Zn
Using a metal as a target, Sn-doped ZnO
Å formed.

Next, 2.0 × 10 ⁻³ Torr of only Ar is used.
In an atmosphere of r, an Ag film is
0 ° was formed, and then a very thin Sn-doped Zn film of about 20 ° was formed using a target of ZnSn metal containing 3.0 atomic% of Sn with respect to the total amount of Zn without changing the atmosphere. Finally, 2.0 × 10 ^{−3 of} Ar: O ₂ = 1: 9
In an atmosphere of Torr, a Sn-doped ZnO film was formed on the Ag film by using a target of ZnSn metal containing 3.0 atomic% of Sn with respect to the total amount of Zn.

During the formation of the last Sn-doped ZnO film, S
Since the n-doped Zn film was oxidized into an Sn-doped ZnO film in an oxidizing atmosphere, the total thickness of the Sn-doped ZnO film formed on the Ag film was 450 °. The substrate temperature is room temperature, sputtering power density in the film formation, at the time of forming the Sn-doped ZnO film during the film deposition of 2.7 W / cm ^2, Ag film was 0.7 W / cm ^2. Note that the ratio of Sn and Zn in the Sn-doped ZnO film was the same as the ratio in the target.

The heat ray shielding film was subjected to a moisture resistance test in which it was left in an atmosphere at 50 ° C. and a relative humidity of 95% for 6 days. The appearance after the moisture resistance test was good, although very fine spots were observed, but no noticeable white spots and white turbidity were observed.

[0037] The Comparative Example dc sputtering on a glass substrate, Ar:
In an atmosphere of 2.0 × 10 ⁻³ Torr with O ₂ = 1: 9,
A ZnO film was formed at 450 ° using Zn metal as a target.

Next, 2.0 × 10 ⁻³ Torr of only Ar is used.
In an atmosphere of r, an Ag film is
0 ° and then, without changing the atmosphere, forming a very thin Zn film of about 20 ° using Zn metal as a target,
Finally, 2.0 × 10 ⁻³ Torr of Ar: O ₂ = 1: 9
A ZnO film was formed on the Ag film by using Zn as a target in the above atmosphere.

During the formation of the last ZnO film, the Zn film was oxidized in an oxidizing atmosphere to become a ZnO film. Therefore, the total thickness of the ZnO film formed on the Ag film was 450 °. The substrate temperature is room temperature, sputtering power density in the film formation, during the film deposition of the ZnO film during the film formation of 2.7 W / cm ^2, Ag film was 0.7 W / cm ^2.

The obtained heat ray shielding film was subjected to the same moisture resistance test as in the above example. As a result, after the moisture resistance test, clear white spots having a diameter of 1 mm or more and white turbidity were observed at the periphery.

[0041]

The heat ray shielding film according to the present invention has remarkably improved moisture resistance. For this reason, it is considered that handling with a single plate becomes easy. In addition, it can be stored for a long time in a single plate. Furthermore, it leads to improvement in reliability of heat ray shielding glass for automobiles and buildings. In addition, even when the laminated glass is used, it is not deteriorated by the moisture contained in the interlayer film, so that the durability of the laminated glass for automobiles and buildings is improved.

Since the heat ray blocking film of the present invention has a metal film, it has conductivity as well as heat ray blocking performance. Therefore, the heat ray blocking film of the present invention can be used in various technical fields utilizing this conductivity. For example, in the field of electronics, it can be used as an electrode (which can also be used as an electrode of a solar cell), as a heating element in an electrically heated window, and as an electromagnetic wave shielding film in windows and electronic components.
The heat ray blocking film of the present invention can be formed on a substrate through films having various functions, and the optimal thickness of each film of the heat ray blocking film of the present invention can be selected, so that an optical film can be formed according to its use. Performance can be adjusted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a heat ray blocking glass in which a heat ray blocking film according to the present invention is formed on glass.

[Explanation of symbols]

 1: substrate 2: oxide film 3: metal film 4: oxide film (B)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C03C 17/00-17/34

Claims (2)

(57) [Claims] 1. A heat ray blocking film composed of (2n + 1) layers (n ≧ 1) alternately laminated with an oxide film, a metal film, and an oxide film on a substrate, when viewed from the substrate, is farthest from the substrate. Was
An oxide film (B) formed on a metal film (A) containing Ag as a main component contains at least one zinc oxide film having a Sn content of 1 to 4 atomic% with respect to the total amount of Zn. Blocking membrane. 2. An oxide film other than the oxide film (B) has at least one layer of Si, Ti, Cr, B, Mg, S
The heat ray blocking film according to claim 1, wherein the total amount of at least one of n and Ga is a zinc oxide film of 1 to 10 atomic% based on the total amount with Zn.