JPH02901A - Optical body having excellent durability - Google Patents

Abstract

PURPOSE:To obtain the optical body having excellent chemical stability and wear resistance by using an amorphous oxide film to the outermost side viewed from a substrate, i.e. the extreme outside layer on an air side. CONSTITUTION:The substrate consists of transparent or colored glass or plastic, etc. A 1st layer 2 consists of a metal, nitride, carbide, oxide or the composite composed thereof and the 2nd layer 3 consists of the amorphous oxide film which is the extreme outside layer on the air side. The amorphous oxide film of the 2nd layer 3 is good if the film is amorphous when the film is examined by X-rays; more specifically, the composite oxide film contg. at least one kind selected from the group of titanium, zirconium, hafnium, tin, tantalum, and indium and at least one kind of boron or silicon. The excellent wear resistance and the sufficient chemical stability are simultaneously obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a highly durable optical body having various optical functions.

[Conventional technology] Conventionally, optical functions have been added by forming thin films on transparent substrates such as glass or plastic, such as mirrors, heat-reflecting glasses, low-emission glasses, interference filters, and anti-reflection for camera lenses and eyeglass lenses. There are coats etc.

In a normal mirror, Ag is formed by an electroless plating method, or AI, Cr, etc. are formed by a vacuum evaporation method, a sputtering method, or the like. Among these, the Cr film is relatively strong, so it is partially used as a surface mirror with an exposed coated surface.

Heat-reflective glass has been formed using titanium oxide, tin oxide, or the like by a spray method, a CVD method, or a dipping method. Recently, metal films, nitride films, tin-doped indium oxide (ITO), etc., formed on glass plate surfaces by sputtering have come to be used as heat-reflecting glasses. The sputtering method allows for easy film thickness control and the ability to form multiple films in succession, and in combination with a transparent oxide film, it is possible to design transmittance, reflectance, color tone, etc. For this reason, demand is increasing for architectural applications where design is important.

Low-emissivity glass (low-emissivity glass) that reflects radiant heat from indoor heaters and walls indoors is a three-layer system of ZnO/Ag/ZnO, in which silver is sandwiched between zinc oxides, or ZnO/Ag/Z.
Five-layer system of nO/Ag/ZnO (Patent application 1981-28084
(See No. 4) and is used in the form of double-glazed or laminated glass. In recent years, its popularity in cold regions of Europe has been remarkable.

Anti-reflection coatings for lenses, etc., are made by alternately laminating high refractive index films such as titanium oxide or zirconium oxide and low refractive index films such as silicon oxide or magnesium fluoride.Usually, a vacuum evaporation method is used. During film formation, the substrate is heated to improve scratch resistance.

[Problems to be Solved by the Invention] Antireflection coatings for surface mirrors, single-panel heat-reflecting glasses, lenses, and the like are used with the coated film exposed to the air. For this reason, it must have excellent chemical stability and abrasion resistance, but even low-emission glass can be defective due to scratches during transportation or handling before it is made into double-glazed or laminated glass. For this reason, there is a demand for an optical thin film that is stable and has excellent wear resistance and also serves as a protective film.

To improve durability, a chemically stable and transparent oxide film is usually provided on the air side. These oxide films include titanium oxide, tin oxide, tantalum oxide, zirconium oxide, silicon oxide, etc., and have been selected and used depending on the required performance.

However, although titanium oxide and zirconium oxide have excellent chemical stability, they tend to form crystalline films with large irregularities on the surface, which increases friction when rubbed and has poor wear resistance. .

On the other hand, tin oxide and silicon oxide are weak to acids and alkalis, respectively, and cannot be soaked for long periods of time. Among these, tantalum oxide has both wear resistance and chemical stability, but it cannot be said to be sufficient in terms of wear resistance.

Furthermore, titanium oxide, tin oxide, tantalum oxide, and zirconium oxide have a relatively high refractive index, whereas silicon oxide has a relatively low refractive index, which limits the degree of freedom in optical design when providing various optical functions. be.

As described above, there is no known thin film that has both high durability and a wide degree of freedom in optical design.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and is directed to an optical body in which an optical thin film consisting of at least two layers is formed on a substrate, in which the outermost layer on the air side is The present invention provides an optical body having excellent durability and characterized by being made of an amorphous oxide film.

FIG. 1 shows a cross-sectional view of an example of an optical body according to the present invention, where ① is a substrate made of transparent or colored glass or plastic, and 2 is a substrate made of metal, nitride, carbide, oxide, or any of these. The first layer consists of a composite of
3 indicates an amorphous oxide film which is the outermost layer on the air side, particularly a second layer made of an oxide containing at least zirconium and boron.

FIG. 2 shows a cross-sectional view of another example of the optical body according to the present invention, where jO is various substrates similar to the above-mentioned substrate l,
11 is a first layer made of a transparent dielectric film, 12 is a second layer made of a nitride film, and 13 is an amorphous oxide film which is the outermost layer on the air side, especially an oxide containing at least zirconium and boron. This shows the third layer.

As described above, the present invention has at least a two-layer structure, but depending on the case, the substrate l and the first layer 2. 1st layer 2
and the second layer 3, or the substrate lO and the first layer 11 in FIG.
, the first layer 11 and the second layer 12, or the second layer 12 and the third layer 1
3. One layer or multiple layers may be formed between the 3 and 3 layers to improve adhesion, adjust optical properties, or provide various other functions. 1 The most significant feature of the present invention is that By forming an amorphous oxide film on the outer layer, it is possible to create an optical body with excellent wear resistance and chemical stability.

The amorphous oxide film of the second layer 3 in FIG. 1 or the third layer 13 in FIG. 2 is not particularly limited as long as it is amorphous when viewed from X-rays. Specifically, a composite oxide film containing at least one member selected from the group of titanium, zirconium, hafnium, tin, tantalum, and indium and at least one member of boron or silicon is preferable. A composite oxide film containing boron is preferable because it has excellent scratch resistance and sufficient chemical stability.

As described above, when an oxide containing zirconium and boron is used for the second layer 3 or the third layer 13, the boron content is not particularly limited. Although the refractive index of the film decreases from 2.1 to below 1.8, both abrasion resistance and chemical stability are good. Therefore, the boron content can be selected based on the optically required refractive index; numerically, the boron content is 1 part or more, preferably 3 parts or more, especially 5 parts or more in atomic ratio per 100 parts of zirconium. Boron is preferred. If the boron content is less than this, sufficient amorphization cannot be obtained, resulting in a decrease in wear resistance, and the superiority over ordinary boron-free zirconium oxide is no longer recognized.

On the other hand, the upper limit of the boron content is not particularly limited, but it is preferably 2000 parts or less, preferably 1000 parts or less, particularly 500 parts or less in atomic ratio to 100 parts of zirconium. If the amount of boron is higher than this, the refractive index becomes very small, the chemical stability becomes insufficient, and the abrasion resistance also decreases, which is not preferable.

Such an oxide film containing zirconium and boron is not limited to the three components of zirconium, boron, and oxygen, but also has improvements in durability, adjustment of optical constants, stability during film formation, and improvement in film formation speed. It goes without saying that there is no problem even if other ingredients are included. Further, the amorphous oxide film of the present invention does not necessarily have to be transparent, and an absorbent film in an oxygen-deficient state or a film containing -partial nitrogen is equally effective.

The thickness of the second layer 3 or the third layer 13, which is the outermost layer, is not particularly limited and may be determined depending on the application by considering the transmitted color and reflected color, but if it is too thin, it may not have sufficient durability. 50 Å or more, preferably 100 Å or more,
In particular, it is desirable that the thickness be 200 Å or more.

The film forming method for the second layer 3 or the third layer 13 is not particularly limited. Any method such as a vacuum evaporation method, an ion blating method, or a sputtering method is possible, but heat ray reflective glass or the like may be used.
When large-area coating is required, such as for automobiles or architecture, reactive sputtering is preferred because of its excellent uniformity.

The film material of the first layer 2 is not particularly limited, and is selected from metals, nitrides, carbides, borides, oxides, silicides, or composites thereof depending on the application or required specifications.

In the case of heat ray reflective glass, the first layer 2 is mainly selected from nitrides such as titanium nitride, zirconium nitride, hafnium nitride, chromium nitride, tantalum nitride, or tin-doped indium oxide (ITO).

The thickness of the nitride film of the first layer 2 is preferably 1000 Å or less, preferably 500 Å or less, although it depends on the desired transmittance. If it exceeds 100 OA, the absorption of the nitride film becomes too large and peeling tends to occur due to internal stress.

When using a nitride film, it is effective to form another layer between the substrate and the nitride film to form a three-layer structure as shown in FIG. 2 in order to increase adhesion to the glass interface. The first layer 11 is preferably a transparent dielectric film made of an oxide such as titanium oxide, zirconium oxide, hafnium oxide, tin oxide, tantalum oxide, indium oxide, or zinc sulfide.
Considering the adhesion with the nitride film of the second layer 12 and productivity in sputtering, a dielectric film containing the same elements as the nitride film of the second layer is preferable, but it is not limited to this. The combination of the first layer II/second layer 12 can be various, such as tantalum oxide/titanium nitride, zirconium oxide/titanium nitride, or tin oxide/zirconium nitride. The transparent dielectric film of the first layer 11 may be the same as the amorphous film described above.

The film thickness of such dielectric material lll11 is not particularly limited, but
These dielectrics have a large refractive index, and if an appropriate film thickness is selected, it is possible to adjust the reflectance and color tone by utilizing interference effects. In particular, when used in heat-reflecting glass that aims to achieve high transmission and low reflection in the visible range by utilizing the interference effect, the first
The thickness of the layer 11 and the third layer 13 is 1000 to 1 in terms of optical thickness.
Preferably, the range is adjusted to 800 people. First layer 11
It is desirable that the refractive index of the third layer 13 is selected within the range of 2.0 to 2.5, but even outside this range, it is acceptable as long as the optical film thickness is within an appropriate range. The thickness of the nitride film of layer 12 is preferably 1000 Å or less, although it depends on the desired transmittance, and is optimally in the range of 50 to 500 Å. 100
If the number exceeds 0, the absorption of the nitride film becomes too large, and
Peeling is likely to occur due to internal stress.

When the outermost layer of the second layer 3 or the third layer 13 is an oxide film containing zirconium and boron, between the first layer 2 and the second layer 3,
Alternatively, boron may be used as the first layer 2 or the second layer 12 in order to improve the adhesion between the second layer 12 and the third layer 13 and reduce the internal stress of the first layer 2 or the second layer 12. It is effective to use nitrides containing zirconium nitride, especially zirconium nitride.

The first layer 2 is made of tin-doped indium oxide (ITO).
), it is desirable to use ITO with a high carrier concentration and mobility and a film thickness of 4000 Å or more in order to improve heat ray reflection performance.In order to suppress reflected color due to interference, ITO should be formed with a thickness of at least 7000 Å or more. is preferred. A second layer 3 is formed thereon as a protective layer. Such a low-resistance, high-transmittance, and durable optical thin film can be used not only as heat-reflecting glass, but also as a single-pane window glass for shielding electromagnetic waves, an electrically heated windshield for automobile windshields, and a defogger for rear windows. Alternatively, it can be used as a transparent antenna. Furthermore, by taking advantage of its chemical durability, it can also be used as a protective coat for ITO (power supply electrode) of electrochromic display elements.

In the case of low-reflection glass, a film having a higher refractive index than the outermost layer 3 on the air side is formed as the first layer 2, or a multilayer structure of three or more layers is used. In the case of a 3-layer film,
By forming another layer between the substrate 1 and the first layer 2 or between the first layer 2 and the second layer 3 in FIG. 1 and adjusting the refractive index and film thickness, the reflectance is reduced. The first layer 2 and the newly inserted layer are not particularly limited, but it is also possible to use a low refractive index film and a high refractive index film having different boron contents.

In the case of low-emission glass, it has a three-layer structure of substrate/oxide film/Ag/amorphous oxide film (especially an oxide film containing boron and zirconium), or substrate/oxide film/Ag/oxide film/Ag.
/It is effective to have a five-layer structure of amorphous oxide films. Such an oxide film is not particularly limited, but an example is ZnO, and an oxide film containing zirconium and boron may also be used.

When applied to a surface mirror, a metal such as ROM, which has good adhesion to glass, is formed as the first layer 2 on the substrate, and on top of that, the amorphous oxide film of the present invention is formed as the second layer 3. In particular, an oxide film containing boron and zirconium may be formed.

The substrate 1 or 10 is usually made of glass, plastic, or the like. When used as a mirror, the substrate is not limited to this, and an opaque substrate such as metal or ceramic may be used as long as it is smooth.

As for other applications, although it is not an optical thin film, it can also be used as a protective film for memory denosks such as thermal heads and magnetic disks.

Further, in the present invention, the optical thin film may be formed on only one side of the substrate as shown in FIGS. 1 and 2, or may be formed on both sides of the substrate.

[Function] The amorphous oxide film that is the outermost layer on the air side of the optical body in the present invention, that is, the second layer 3 in FIG. 1 or the third layer 13 in FIG. The optical body of the present invention is made amorphous by containing silicon, which increases the smoothness of the surface and reduces frictional resistance, resulting in high durability. It plays the role of a protective layer to improve chemical properties, and furthermore, by adjusting its refractive index, film thickness, etc., it has optical functions, that is, functions to adjust transmittance, reflectance, color tone, etc.

In particular, when the outermost layer is an oxide film containing zirconium and boron, boron is added to zirconium oxide, which has strong chemical stability against acids and alkalis, and the film becomes amorphous, making it resistant. This contributes to the realization of a highly durable film that satisfies both abrasion resistance and chemical stability.

Boron also contributes to adjusting the refractive index of the film.

That is, the refractive index can be lowered by increasing the boron content.

In the present invention, the layers other than the outermost layer mainly have an optical function, and are responsible for transmission and reflection performance.

In addition, in an optical body having heat ray reflecting performance, the nitride film also has a heat ray reflecting function. In addition, in heat-reflecting glass that uses interference effects to achieve high transmission and low reflection in the visible range, the second layer 12 in FIG. 2 has a heat-reflecting function, and the first layer 11 and The three layers 13 have a function of preventing reflection of the nitride film in the visible range.

[Example] (Example 1) A glass substrate was set in a vacuum chamber of a sputtering device.
It was evacuated to 116 Torr. Introduce a mixed gas of argon and nitrogen to increase the pressure to 2 x 1O-3Torr
After that, about 200 titanium nitrides (first layer) were formed by reactive sputtering of titanium.Then, the pressure was changed to a mixed gas of argon and oxygen at 2 x 1O-3 Torr.
r, zirconium/boron target (atomic ratio 70
/ 30) was reactively sputtered to form an amorphous oxide 115IZrBxOy (second
A group of approximately 500 people was formed.

Visible light transmittance TV of the heat ray reflective glass obtained in this way,
Sunlight transmittance TE, coating surface visible light reflectance RVF,
The glass surface visible light reflectance RVG is 53.42.
The film was immersed in 1 N hydrochloric acid or sodium hydroxide for 6 hours, or in boiling water for 2 hours to check its durability, but both of the transmittance and reflectance were 8.28 (%). Changes were within 1%.

Even in a rubbing test with a sand eraser, there were almost no scratches and it showed extremely excellent abrasion resistance.

(Example 2) Titanium nitride (first layer) was deposited on a glass substrate as in Example 1.
After forming about 200 people, we switched to a mixed gas of argon and oxygen and set the pressure to 2 x 1O-3 Torr to create a zero-order zirconium/boron target (atomic ratio 33/13?).
) was reactively sputtered to form an amorphous oxide film ZrBx07 (second layer) consisting of zirconium and boron (approximately 500%
Formed a person.

Optical performance TvTE, RV of the obtained heat ray reflective glass
F, RVG are 55.42.3.20 (%) respectively
Met.

A durability test similar to that in Example 1 was conducted, and similarly excellent performance was shown.

(Example 3) A glass substrate was set in a vacuum chamber of a sputtering device.
It was evacuated to X 10-6 Torr. Introducing a mixed gas of argon and oxygen and increasing the pressure to 2 x 1O-3Tot
r, heat the substrate to about 350°C, and then sputter an ITO target to deposit about 10% of the ITO (first layer).
Zirconium/boron target (atomic ratio 33/8) with different ratio of zero-order argon and oxygen mixed gas
7) by reactive sputtering to form an amorphous oxide film ZrBx.
07 (second tier) was formed with approximately 780 people.

The durability of the thus obtained heat ray reflective glass was evaluated in the same manner as in Example 1, and it was found to have extremely excellent durability.

(Example 4) A glass substrate was set in a vacuum chamber of a sputtering device.
It was evacuated to X 10-6 Tarr. Introducing a mixed gas of argon and oxygen and increasing the pressure to 2 x 1O-3 Torr
Then, about 620 tantalum oxides (first layer) were formed by reactive sputtering of tantalum. Subsequently, a zirconium/boron target (atomic ratio 33/87) was similarly reactively sputtered to form an amorphous oxide film ZrBxO.
y (second tier) was formed with approximately 760 people.

Once the vacuum was leaked and the substrate was turned over, a similar two-layer film was again formed on the back side.

The reflectance of the low-reflection glass thus obtained is approximately 1.
It was 5%. Further, the durability was also extremely excellent as in Example 1.

(Example 5) A glass substrate was set in a vacuum chamber of a sputtering device,
It was evacuated to I x 10-6 Torr. A mixed gas of argon and oxygen is introduced to increase the pressure to 2×1 (13 Torr).
After that, a zirconium target containing boron is subjected to high-frequency magnetron sputtering to form an amorphous oxide film ZrBx.
After forming about 600 Oy (first layer), switch to a mixed gas of argon and nitrogen and increase the pressure to 2 x 1O-3.
Approximately 120 titanium nitride layers (second layer) were formed by high-frequency magnetron sputtering using a titanium target at Torr. After that, ZrBx (
The h film (third layer) was formed to about SOO.

The visible light transmittance TV and sunlight transmittance TE of the sample thus obtained were approximately 80% and 60%, respectively. A durability test similar to that in Example 1 was conducted, and similar to Example 1, excellent performance was shown.

(Example 6) A glass substrate was set in a vacuum chamber of a sputtering device,
It was evacuated to 10-6 Torr. After introducing a mixed gas of argon and oxygen to set the pressure to 2×101 Torr, a titanium target containing silicon was subjected to high-frequency magnetron sputtering to form an amorphous oxide film Ti5ixOY.
Approximately 600 people formed the membrane (first layer). Next, switch to a mixed gas of argon and nitrogen and increase the pressure to 2
Approximately 120 titanium nitride layers (second layer) were formed by high-frequency magnetron sputtering using a titanium target. After that, the amorphous oxide film T is again made under the same conditions as the first layer.
About 800 people formed i5ixOy (third tier).

The visible light transmittance and sunlight transmittance of the sample thus obtained were almost the same as those of Example 5. Furthermore, the same results as in Example 5 were obtained regarding durability.

(Comparative Example 1) In order to see the effect of Example 5, about 600 people formed a zirconium oxide film (first layer) that did not contain boron. Next, the mixture gas of argon and nitrogen was changed to a gas mixture of argon and nitrogen, and the pressure was increased to 2×1O.
Titanium nitride (second layer) was deposited by high-frequency magnetron sputtering using a titanium target at −3 Torr.
0 people formed. Thereafter, about 600 people formed a zirconium oxide film (third layer) again under the same conditions as the first layer.

When the sample thus obtained was subjected to a sand eraser test, the abrasion resistance was poor and many scratches occurred.

(Comparative Example 2) In order to see the effect of Example 6, about 600 people formed a titanium oxide film (first layer) that did not contain silicon. Next, switch to a mixed gas of argon and nitrogen and increase the pressure to 2 x 101To
Approximately 120 titanium nitride layers (second layer) were formed by high-frequency magnetron sputtering using a titanium target. After that, the titanium oxide film (
Approximately 600 people formed the third layer.

When the sample thus obtained was subjected to a sand eraser test, it had poor abrasion resistance and a large number of scratches occurred.

[Effects of the Invention] The present invention improves chemical stability and resistance by using an amorphous oxide film as the outermost layer on the outermost side of the substrate, that is, on the air side, as shown in Examples 1 to 6. It is possible to obtain an optical body with excellent abrasion resistance.

Furthermore, when using an amorphous oxide film containing boron, the refractive index of the oxide film can be adjusted by changing the boron content, increasing the degree of freedom in optical film formation. It also has the effect of enlarging it.

[Brief explanation of the drawing]

FIG. 1 shows a partial cross-sectional view of an example of an optical body according to the present invention, and FIG. 2 shows a partial cross-sectional view of an example of an optical body having heat ray reflecting performance according to the present invention. 1.10: Substrate 2: Metal, nitride, carbide, boride, oxide film, silicide,
Or a film made of a composite of these (first layer) 3: Amorphous oxide film (82 layers) 11: Transparent dielectric film (first layer)! 2: Nitride film (second layer)

Claims (6)

[Claims] (1) An optical body having excellent durability, in which an optical thin film consisting of at least two layers is formed on a substrate, and the outermost layer on the air side is made of an amorphous oxide film. (2) The amorphous oxide film is made of an oxide containing at least one member selected from the group consisting of titanium, zirconium, hafnium, tin, tantalum, and indium, and at least one member of boron or silicon. The optical body with excellent durability according to claim 1. (3) The optical body with excellent durability according to claim 1, wherein the amorphous oxide film is an oxide film containing at least zirconium and boron. (4) A heat ray reflection according to any one of claims 1 to 3, characterized in that at least a two-layer film consisting of a nitride film and an amorphous oxide film is formed on the substrate in this order from the substrate side. A highly durable optical body with excellent performance. (5) Any one of claims 1 to 3, wherein at least a three-layer film consisting of a transparent dielectric film, a nitride film, and an amorphous oxide film is formed on the substrate in order from the substrate side. A highly durable optical body having heat ray reflection performance as described in 1. (6) Claim 4 characterized in that the nitride film is made of at least one member selected from the group of titanium nitride, zirconium nitride, hafnium nitride, tantalum nitride, and chromium nitride.
Or the highly durable optical body having heat ray reflection performance according to 5.