KR20110079991A - Multi-layer thin film for low emissivity and automobile glass containing the same - Google Patents

Abstract

The present invention relates to a hot-reflective multilayer thin film and an automotive glass including the same, wherein the heat-reflective multilayer thin film according to the present invention is a high-refractive transparent thin film and a hot-reflective metal thin film repeatedly laminated on a transparent substrate, and a high-refractive transparent thin film and a hot-reflective metal A heat ray reflection multilayer thin film in which a protective thin film is laminated between thin films, wherein the high refractive transparent thin film is a metal oxide having a compressive stress, and the protective thin film is formed of a metal having a tensile stress that attenuates the compressive stress of the high refractive transparent thin film. .

Description

Multi-layer thin film for Low emissivity and automobile glass containing the same}

The present invention relates to a heat ray reflection multilayer thin film and an automotive glass including the same, and more particularly, to a heat ray reflection multilayer thin film and an automobile glass including the same that can prevent the durability of the heat ray reflection laminate from being compressed.

Typically, the solar energy reaching the earth's surface occupies about 6% ultraviolet light, about 46% visible light, and about 48% infrared light. That is, half of the solar energy does not contribute to the light and generates heat. In the summertime, 71% of the heat flowing from the outside of the building to the inside comes from the glass, so the reduction of heat can be expected to achieve significant energy savings.

In recent years, with increasing interest in energy saving and cooling efficiency, heat ray reflection glass (or low-e glass) that transmits visible light incident from sunlight and reflects heat rays (infrared rays) is also known. Is in progress.

Hot-reflective glass is largely made by two methods. The first method is to coat a single layer of semiconductors (e.g. ITO, SnO2: F, etc.) with largely degenerated bad gabs, and the second method is transparent in the visible region on a transparent substrate. And a high refractive transparent thin film and a heat ray reflective metal thin film having a refractive index of 1.45 or more and 2.5 or less in a multilayer thin film structure.

The heat-reflective glass manufactured by the first method is called hard coating glass because of its excellent chemical and physical properties. The heat-reflective glass manufactured by the second method is soft because it has relatively low chemical and physical durability. It's called Yuri. The heat reflectivity of double soft coated glass is better than that of hard coated glass. Currently, the production of soft coating glass is being made worldwide because vacuum deposition technology that can produce soft coating glass in a large scale and reproducibility is common.

By the way, in the case of the hot-reflective glass manufactured by the soft coating method, there is a problem in that the durability of the hot-reflective metal thin film, in particular, moisture resistance, deteriorates with time as the compressive stress of the high refractive transparent thin film exists.

The present invention has been proposed in the above background, and an object of the present invention is to provide a heat-reflective multilayer thin film and an automotive glass including the same that can prevent the durability of the heat-reflective metal thin film due to the compressive stress.

In order to achieve the above object, the heat-reflective multilayer thin film according to an aspect of the present invention, a high refractive index transparent film and a heat-reflective metal thin film is repeatedly laminated on a transparent substrate, a protective thin film between the high-refractive transparent film and the heat-reflective metal thin film As the laminated heat ray reflection multilayer thin film, the high refractive transparent thin film is a metal oxide having a compressive stress, and the protective thin film is formed of a metal having a tensile stress that attenuates the compressive stress of the high refractive transparent thin film.

Preferably, the high refractive index transparent thin film is a metal oxide having a compressive stress of 0.1 GPa or more and 0.2 GPa or less, and the protective thin film is formed of a metal having a tensile stress of 1.0 GPa or more and 2.0 GPa or less.

Preferably, the thickness of the high refractive transparent thin film is 30nm or more, 36nm or less, the protective thin film is characterized in that the thickness is 1.0nm or more, 4.0nm or less.

Preferably, the high refractive index thin film is niobium pentoxide (Nb ₂ O ₅ ), the protective film is characterized in that formed of any one of aluminum (Al), chromium (Cr), nickel (Ni), nickel chromium (NiCr). .

The heat ray reflection multilayer thin film according to the present invention configured as described above is useful for improving the durability, especially moisture resistance, of the heat ray reflection metal thin film by reducing the compressive stress of the high refractive transparent thin film which affects the heat ray reflection metal thin film. It works.

In particular, when the high refractive index thin film is implemented with niobium pentoxide (Nb ₂ O ₅ ), light absorption in the blue region is less, resulting in a clear color, which has a useful effect of improving visibility.

In addition, the heat ray reflecting multilayer thin film according to the present invention has a high refractive index thin film of 30nm or more, 36nm or less, the thickness of the protective film is 1.0nm or more, 4.0nm or less, the tensile stress of the first and second protective thin film While the compressive stress of the high refractive transparent thin film is sufficiently attenuated, there is a useful effect of not lowering the light transmittance.

1 is an exemplary view for explaining a heat ray reflection multilayer thin film according to the present invention,
2 is a cross-sectional view of a heat ray reflection multilayer thin film according to a first embodiment of the present invention;
3 is a cross-sectional view of a heat ray reflection multilayer thin film according to a second embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand and reproduce the present invention.

1 is an exemplary view for explaining a heat ray reflection multilayer thin film according to the present invention.

As shown, the heat ray reflection multilayer thin film 10 according to the present invention includes a first high refractive index transparent film 12a, a first passivation thin film 13a, a heat ray reflection metal thin film 14, and a second layer on the transparent substrate 11. The multilayer thin film structure consisting of the protective thin film 13b and the second high refractive transparent thin film 12b in that order is repeatedly stacked.

The transparent substrate 11 is not limited as long as it has excellent light transmittance and excellent mechanical properties. For example, the transparent substrate 11 is an organic film capable of thermal curing or UV curing, mainly a polymer-based material such as polyethylene terephthalate (PET), acryl (Acryl), polycarbonate (PC), urethane acrylate (Urethane Acrylate) , Polyester (Polyester), epoxy acrylate (Epoxy Acrylate), polyvinyl chloride (PVC) can be implemented. In addition, the transparent substrate 11 may be formed of soda-lime glass or aluminosilicate glass (SiO ₂ -Al ₂ O-Na ₂ O) as chemically strengthened glass, and the amount of Na and Fe is It can be adjusted low depending on the application.

The first and second high refractive index thin films 12a and 12b may be formed of a metal oxide having a compressive stress of 0.1 GPa or more and 0.2 GPa or less, for example, niobium pentoxide (Nb ₂ O ₅ ). Preferably, the thicknesses of the first and second high refractive transparent thin films 12a and 12b are 30 nm or more and 36 nm or less.

When the first and second high refractive index transparent films 12a and 12b are formed of niobium pentoxide (Nb ₂ O ₅ ), for example, the heat ray reflection multilayer thin film 10 of the present invention may be formed on automotive glass. Typically, automotive glass is subjected to a heat treatment process of a heating temperature of 650 ℃ or more, 750 ℃ or less for strengthening or curved surface treatment. Niobium pentoxide (Nb ₂ O ₅ ) is a material having a coefficient of thermal expansion similar to that of the transparent substrate 11, and prevents crack generation of the thin film after heat treatment and exhibits excellent moisture resistance characteristics.

The first and second protective thin films 13a and 13b serve to attenuate the compressive stresses of the first and second high refractive transparent thin films 12a and 12b. For example, the first and second protective thin films 13a and 13b may be formed of any one of aluminum (Al), chromium (Cr), nickel (Ni), and nickel chromium (NiCr). Preferably, the thicknesses of the first and second protective thin films 13a and 13b are 1.0 nm or more and 4.0 nm or less.

The heat ray reflecting metal thin film 14 is made of a material having high light transmittance in the visible light region (380 nm to 780 nm) while high light reflectance in the infrared region. For example, the heat ray reflective metal thin film 14 may be formed of silver (Ag) or an alloy containing silver (Ag) as a main component.

2 is a cross-sectional view of a heat ray reflection multilayer thin film according to a first embodiment of the present invention.

The heat ray reflection multilayer thin film 20 according to the present embodiment is niobium pentoxide (Nb ₂ O ₅ ) / chromium (Cr) / silver (Ag) / chromium (Cr) / on a soda-lime glass 21. The multilayer thin film structures 22, 23, and 24 stacked in the order of niobium pentoxide (Nb ₂ O ₅ ) are repeatedly stacked three times. Herein, niobium pentoxide (Nb ₂ O ₅ ) has a compressive stress of 0.1 GPa or more and 0.2 GPa or less, and the tensile stress of chromium (Cr) is implemented to 1.0 GPa or more and 2.0 GPa or less.

3 is a cross-sectional view of a heat ray reflection multilayer thin film according to a second embodiment of the present invention.

The heat ray reflection multilayer thin film 30 according to the present embodiment is made of niobium pentoxide (Nb ₂ O ₅ ) / aluminum (Al) / silver (Ag) / aluminum (Al) / on a soda-lime glass 31. The multilayer thin film structures 32, 33, and 34 stacked in the order of niobium pentoxide (Nb ₂ O ₅ ) are repeatedly stacked three times. Here, niobium pentoxide (Nb ₂ O ₅ ) has a compressive stress of 0.1 GPa or more and 0.2 GPa or less, and the tensile stress of aluminum (Al) is 1.0 GPa or more and 2.0 GPa or less.

Hereinafter, the results of measuring the defect area ratio (ppm), sheet resistance (Ω / □), and light transmittance according to the thickness of the thin film of the heat ray reflection multilayer thin film according to FIGS. 2 and 3 will be described.

Multilayer thin film structure Each thin film thickness (nm) Defect area ratio (ppm) Sheet resistance Transmittance Example 1
G / (Nb ₂ O ₅ / Cr / Ag / Cr / Nb ₂ O ₅ ) × 3 30/3/13/3/30 0 1.3 75% Example 2 33/3/13/3/33 2 1.3 74% Example 3 30/2/13/2/30 6 1.2 79% Example 4 G / (Nb ₂ O ₅ / Al / Ag / Al / Nb ₂ O ₅ ) × 3 30/3/13/3/30 0 1.3 76% Comparative Example 1 G / (TiO ₂ / Cr / Ag / Cr / TiO ₂ ) × 3 28/3/13/3/28 13 1.3 77% Comparative Example 2 G / (SnO ₂ / Cr / Ag / Cr / SnO ₂ ) × 3 36/3/13/3/36 350 1.5 71% Comparative Example 3 G / (Nb ₂ O ₅ / ITO / Ag / ITO / Nb ₂ O ₅ ) × 3 28/5/13/5/28 136 1.2 78%

Here, G is soda-lime glass, and the defect area ratio (ppm) is the heat-reflective multilayer thin film in a thermo-hygrostat maintained at a temperature of 60 ° C. and a relative humidity of 80% for 7 days, and then the defect part is examined under a microscope. Measured using. The sheet resistance (Ω / □) was measured using an RSM-10 non-contact sheet resistance meter and the light transmittance using a Lambda-950 spectrophotometer. Here, the defect area ratio (ppm) was calculated by dividing the area of the identified defect by the area to be inspected, and the light transmittance was measured by using a Lambda-950 spectrophotometer to measure spectral transmittance and spectral reflectance in the range of 380 nm to 780 nm. Was calculated.

Examples 1, 2, and 3 are niobium pentoxide (Nb ₂ O ₅ ) / chromium (Cr) / silver (Ag) / chromium (Cr) / niobium pentoxide (Nb ₂ O ₅ ) on soda-lime glass. The laminated multilayer thin film structure was sequentially laminated three times. In Example 1, 2, and 3, the thin film thickness of niobium pentoxide (Nb ₂ O ₅ ) was 30 nm, 33 nm, and 30 nm, respectively, and the thin film thickness of chromium (Cr) 3 nm, 3 nm, and 2 nm, respectively, and the thin film thickness of silver (Ag) was 13 nm, respectively, and the defect area ratio (ppm), sheet resistance (Ω / □), and light transmittance were measured.

Example 4 is laminated on a soda-lime glass in order of niobium pentoxide (Nb ₂ O ₅ ) / aluminum (Al) / silver (Ag) / aluminum (Al) / niobium pentoxide (Nb ₂ O ₅ ) in order. The multilayer thin film structure was repeatedly laminated three times. In Example 4, the thin film thickness of niobium pentoxide (Nb ₂ O ₅ ) was 30 nm, the thin film thickness of aluminum (Al) was 3 nm, and the thin film thickness of silver (Ag) was 13 nm. The defect area ratio (ppm), sheet resistance (kPa / square), and light transmittance were measured.

In Example 1, the defect area ratio (ppm) was 0, the sheet resistance (저항 / □) was 1.3, and the light transmittance was measured at 75%. In Example 2, the defect area ratio (ppm) was 2, the sheet resistance (저항 / □) was 1.3, and the light transmittance was measured at 74%. In the case of Example 3, the defect area ratio (ppm) was 6, the sheet resistance () / □) was 1.2, and the light transmittance was measured at 79%. In Example 4, the defect area ratio (ppm) was 0, the sheet resistance (저항 / □) was 1.3, and the light transmittance was measured at 75%.

Comparative Example 1 has a multilayer thin film structure in which titanium oxide (TiO ₂ ) / chromium (Cr) / silver (Ag) / chromium (Cr) / titanium oxide (TiO ₂ ) is stacked in order on soda-lime glass. The film was repeatedly laminated three times. In Example 4, the thickness of the thin film of titanium oxide (TiO ₂ ) was 28 nm, the thin film thickness of chromium (Cr) was 3 nm, and the thin film thickness of silver (Ag) was 13 nm. ppm), sheet resistance (Ω / □) and light transmittance were measured.

Comparative Example 2 has a multilayer thin film structure in which tin oxide (SnO ₂ ) / chromium (Cr) / silver (Ag) / chromium (Cr) / tin oxide (SnO ₂ ) is stacked in order on soda-lime glass. By repeating three times, the thin film thickness of tin oxide (SnO ₂ ) was 36 nm, the thin film thickness of chromium (Cr) was 3 nm, and the thin film thickness of silver (Ag) was 13 nm. ppm), sheet resistance (Ω / □) and light transmittance were measured.

Comparative Example 3 is niobium pentoxide (Nb ₂ O ₅ ) / indium tin oxide (ITO) / silver (Ag) / indium tin oxide (ITO) / niobium pentoxide (Nb ₂ O ₅ ) on soda-lime glass The laminated multilayer thin film structure was sequentially stacked three times. In Example 4, the thin film thickness of niobium pentoxide (Nb ₂ O ₅ ) was 28 nm, the thin film thickness of indium tin oxide (ITO) was 5 nm, and silver (Ag ), The defect area ratio (ppm), sheet resistance (Ω / □), and light transmittance were measured.

In the case of the comparative example 1, the defect area ratio (ppm) was 13, the sheet resistance (Ω / square) was 1.3, and the light transmittance was 77%. In the case of Comparative Example 2, the defect area ratio (ppm) was 350, the sheet resistance (Ω / □) was 1.5, and the light transmittance was measured at 71%. In Comparative Example 3, the defect area ratio (ppm) was measured at 136, the sheet resistance (, / □) was 1.2, and the light transmittance was 78%.

In Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, and 3, the multilayer thin film structures of the heat-reflective multilayer thin films were all shown to have a sheet resistance of less than 1.4 (Ω / □) and a light transmittance of 70% or more. The defect area ratio (ppm) shows a big difference. The compressive stress (0.1 GPa) of niobium pentoxide (Nb ₂ O ₅ ) used in Examples 1, 2, 3, and 4, and titanium oxide (TiO ₂ ) and tin oxide (SnO ₂ ) used in Comparative Examples 1 and ₂ ) The decrease in durability due to the difference in compressive stress (1.0GPa, 2.0GPa) was found to be the cause. In addition, in Comparative Example 3, niobium pentoxide (Nb ₂ O ₅ ) was used as in Examples 1, 2, 3, and 4, but there was a difference in the defect area ratio (ppm), which is a tensile strength of indium tin oxide (ITO). It was found that the stress was 0.6 GPa, and the degree of attenuation of the compressive stress of niobium pentoxide (Nb ₂ O ₅ ) was reduced.

Usually, it can be said that it is a heat ray reflection multilayer thin film which has the outstanding characteristic that a defect area ratio (ppm) and sheet resistance (kPa / square) are low, and light transmittance is high. Accordingly, as shown in Examples 1, 2, 3, and 4, the multilayer thin film structure of the heat-reflective multilayer thin film of the present invention has a defect area ratio (ppm) of less than 10 and a sheet resistance of less than 1.4 (Ω / □) and 70%. It is characterized by having the above light transmittance.

Thus far, the present specification has been described with reference to the embodiments shown in the drawings so that those skilled in the art to which the present invention pertains can easily understand and reproduce the present invention. Those skilled in the art will understand that various modifications and equivalent other embodiments are possible from the embodiments of the present invention. Accordingly, the true technical protection scope of the present invention should be defined only by the appended claims.

10, 20, 30: heat ray reflection multilayer thin film
11, 21, 31: transparent substrate
12a: first high refractive transparent thin film 12b: second high refractive transparent thin film
13a: first protective thin film 13b: second protective thin film
14: heat reflection metal thin film

Claims (10)

As a high-reflection transparent thin film and a hot-reflective metal thin film is repeatedly laminated on a transparent substrate, a protective thin film is laminated between the high-refractive transparent thin film and the hot-reflective metal thin film,
The high refractive transparent thin film is a metal oxide having a compressive stress,
The protective thin film is a heat ray reflection multilayer thin film, characterized in that formed of a metal having a tensile stress to attenuate the compressive stress of the high refractive transparent thin film. The method of claim 1,
The high refractive transparent thin film is a metal oxide having a compressive stress of 0.1 GPa or more and 0.2 GPa or less,
The protective thin film is a heat ray reflection multilayer thin film, characterized in that the tensile stress is formed of a metal of 1.0GPa or more, 2.0GPa or less. The method of claim 1,
The high refractive index thin film is 30nm or more, 36nm or less,
The protective thin film is a heat ray reflection multilayer thin film, characterized in that the thickness is 1.0nm or more, 4.0nm or less. The method of claim 1,
The high refractive transparent thin film,
A heat ray reflection multilayer thin film formed of niobium pentoxide (Nb ₂ O ₅ ). The method of claim 1,
The heat ray reflection metal thin film,
A heat ray reflection multilayer thin film, which is formed of silver (Ag) or an alloy containing silver (Ag) as a main component. The method of claim 1,
The protective film,
A heat ray reflection multilayer thin film, which is formed of any one of aluminum (Al), chromium (Cr), nickel (Ni), and nickel chromium (NiCr). The method of claim 1,
The hot-reflective multilayer thin film has a defect area ratio (ppm) of less than 10, a sheet resistance of less than 1.4 (µs / □), and a light transmittance of 70% or more. An automotive glass comprising the heat ray reflection multilayer thin film according to any one of claims 1 to 7. The method of claim 8,
The automotive glass,
Automotive glass, characterized in that the tempered or curved through a heat treatment process. The method of claim 9,
The heating temperature of the heat treatment step is 650 ℃ or more, 750 ℃ or less for automobile glass.

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