JP3192137B2 - Manufacturing method of transparent heat ray reflection glass of radio wave reflection suppression type - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a transparent heat ray reflective glass having a high architectural design without causing a television radio wave reflection obstacle. More specifically, by forming a zirconium nitride film on the surface of a glass substrate by direct current sputtering in a nitrogen-rare gas mixed gas atmosphere containing nitrogen at 30% by volume or more, the reflection attenuation of TV radio waves is increased. And a method for manufacturing the same.

[Related Art] In recent years, in order to improve architectural design and reduce cooling load, transparent heat ray reflecting glass has been frequently used in buildings such as buildings. Among them, the high-performance heat-reflective glass is obtained by coating the surface of a glass substrate with a thin film of a metal, a metal oxide, a metal nitride or the like in a vacuum by a sputtering method or the like, and has the following excellent characteristics.

It has a wide variety of colors such as silver, bronze, blue, and green, so it has excellent architectural design.

Visible light transmittance of 8-40%, visible light reflectance of 10-45% and good balance of visible light create a comfortable indoor space,
It is also effective in protecting privacy.

Since it exhibits excellent solar radiation blocking performance, it helps to reduce the cooling load.

[Problems to be Solved by the Invention] Conventional high-performance heat-reflective glass uses metal or metal nitride as a coating thin film as described above, and has a low surface resistance. It has a property close to that of a plate and tends to have a low return loss.

For example, a conventional high-performance heat ray reflective glass has a coating thin film having a surface resistance value of 250Ω / □ or less, and the return loss of this glass is 7dB or less in a VHF band and a UHF band. The return loss represents the ratio of the reflected radio wave energy to the incident radio wave energy. The larger the value is, the less the reflection is, and the less likely the ghost failure is. If the return loss of the glass is 7 dB or less in the VHF band and the UHF band as described above, ghost interference of television waves may occur depending on the use environment (especially when used in a large area in a high-rise building).

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 method for producing a new transparent heat ray reflective glass that does not cause ghost interference of television radio waves while maintaining excellent architectural design. .

[Means for Explaining the Problem] It is said that the transparent heat ray reflective glass does not cause a problematic ghost failure if the return loss is 15 dB or more. Therefore, first, the surface resistance of a thin film that does not cause ghost damage was determined from the theory. Consider a model in which a television wave is incident on glass having a thin film on the back surface as shown in FIG. This model can be generally rewritten equivalently to a distributed constant circuit as shown in FIG. The input impedance Z _in as seen from the terminal AB on the right side is expressed by the equation (1).

Further, the specific impedance _A and the propagation constant of the glass are represented by the equations (2) and (3), respectively.

Z ₀ : Impedance of space, Z ₀ = 377Ω j: Imaginary unit: Inductance of glass, = 7−0.1jt: Thickness of glass λ ₀ : Wavelength of radio wave On the other hand, a thin film is a perfect reflector such as a metal plate. Since it does not exist, it is represented by the parallel resistance of R and Z ₀ , and its incident characteristic impedance _B is as shown in equation (4).

As described above, the reflectance に よ る of the glass is represented by equation (5).

Therefore, the return loss η is expressed by the following equation (6).

η = 20logΓ (6) Here, when the wavelength λ ₀ = 300 cm (frequency f = 100 MHz) and the glass thickness t = 10 mm, in order to obtain the return loss η ≧ 15 dB necessary for preventing the occurrence of ghost disturbance. Means that the surface resistance of the thin film should be 1000Ω / □ or more.

Thus, as a result of examining a thin film material having a surface resistance value of 1000 Ω / □ or more and having excellent heat ray reflection performance and architectural design, it has been found that a zirconium nitride film formed by a specific manufacturing method is useful. In FIG. 1, the horizontal axis represents the ratio of nitrogen (volume%) to the volume of the mixed gas of nitrogen and argon, and the vertical axis represents a visible light transmittance of 30% formed on a glass substrate by DC sputtering in the gas atmosphere. 5 is a graph showing the surface resistance of the zirconium nitride film of FIG. From the figure, the ratio of nitrogen to mixed gas [N ₂ / (Ar + N
₂ )] shows that the surface resistance of the nitrogen zirconium film formed in a gas atmosphere of 30% by volume or more is 1000Ω / □ or more. Accordingly, such a film can be used as a radio wave reflection suppressing type transparent heat ray reflective film.

That is, according to the present invention, the surface of a glass substrate is
This is a method for producing a radio-reflection-suppressing transparent heat ray reflective glass in which a zirconium nitride film is formed by DC sputtering in a mixed gas atmosphere of nitrogen and a rare gas or a gas atmosphere of 100% nitrogen.

Further, the present invention is a radio wave reflection suppressing type transparent heat ray reflective glass in which a zirconium nitride single layer film having a geometric thickness d of 10 nm ≦ d ≦ 200 nm is formed on the surface of a glass substrate by the above method. Further, the present invention forms a two- to five-layer film of a transparent dielectric film and a zirconium nitride film by the above method on the surface of a glass substrate, and the optical thickness nd of the transparent dielectric film is 5 nm in total.
≦ nd ≦ 300 nm, and a radio-reflection-suppressing transparent heat ray reflective glass in which the total thickness d of the zirconium nitride film is 10 nm ≦ d ≦ 200 nm.

Incidentally, the zirconium nitride film has been often used recently as a titanium decoration film as a golden decoration and wear-resistant film.
For example, a geometric thickness of 100 n formed by sputtering in a mixed gas of nitrogen and argon having a nitrogen content of 10% by volume.
The zirconium nitride film of m has a film surface reflection color of L ^* = 70.5, a ^* = 1.5, b ^* = 32.7 in 2 ° visual field C light (JIS Z8729), and exhibits a bright gold color. The surface resistance of the film is 22Ω
/ □ and conductive. This film is a zirconium nitride film of stoichiometry or a composition close to stoichiometry used for gold decoration, in a mixed gas atmosphere of nitrogen and a rare gas having a nitrogen ratio of 30% by volume or more, or in a gas atmosphere of 100% nitrogen. The zirconium nitride film of the present invention formed by DC sputtering has a different composition from the zirconium nitride film of the present invention.

Here, the thickness range of zirconium nitride is set to 10 nm ≦ d ≦ 200 n
If m is less than 10 nm, the heat ray reflection performance will be reduced, while if it exceeds 200 nm, optical characteristics different from thinner films will not be added, but the film formation time will be longer and the production cost will increase. There is no merit just to do it. The reason why the thickness range of the transparent dielectric film is set to 5 nm ≦ nd ≦ 300 nm in optical thickness is that when the thickness is less than 5 nm, there is almost no effect on the improvement of the optical characteristics and the durability, while forming a thick film exceeding 300 nm. This is also because there is no merit just because the film formation time becomes longer and the cost rises.

In the present invention, the order of the zirconium nitride film and the transparent dielectric film with respect to the glass substrate may be arbitrary. In the case of three or more layers, zirconium nitride films and transparent dielectric films are provided alternately. In the case of a five-layer structure, the transparent dielectric film has three layers.

The film formed on the glass substrate is preferably formed by direct current sputtering. TiO ₂ , ZrO ₂ , Ta ₂ O ₅ ,
Nb ₂ O _{5 and the} like are preferred.

[Operation] The zirconium nitride film formed on the surface of the glass substrate by the above-described method has a surface resistance value of 1000Ω / □ or more and a return loss of 15 dB or more with respect to an incident television wave, so that ghost damage is substantially eliminated. Does not occur. Also, this film exhibits excellent heat ray reflection characteristics. Further, the transmittance and the reflection color can be adjusted by controlling the film thickness or by combining the film with the transparent dielectric film.

The transparent dielectric film is irrelevant to the electrical characteristics, improves transmittance and reflectance, adjusts the reflection color tone, and improves abrasion resistance and chemical resistance.

Example 1 FIG. 2 is a sectional view showing one example of the transparent heat ray reflective glass according to the present invention. This is an example in which a zirconium nitride film 12 having a geometric thickness (physical thickness) d of 36 nm is formed on the surface of a glass substrate 10 by a DC sputtering method.

FIG. 3 schematically shows the DC sputtering apparatus used here. An exhaust port 24 provided with a variable valve 22 is formed in a part of the grounded vacuum chamber 20, and connected to a vacuum pump 26 via the exhaust port 24 so that the pressure in the vacuum chamber 20 can be reduced. A magnetron cathode is provided above the vacuum chamber 20.
28a and 28b are provided and connected to DC power supplies 30a and 30b. A gas supply pipe 34 having a valve 32 is provided between the magnetron cathodes 28a and 28b so that gas can be supplied into the vacuum chamber 20. Further, a reciprocable transport belt 36 is arranged below each magnetron cathode 28a, 28b.

First, a Zr target 38a is attached to the lower surface of the cathode 28a. Then, the washed glass substrate 10 is placed on the substrate holder 40 on the conveyor belt 36, the variable valve 22 is opened, and the pressure in the vacuum chamber 20 is reduced to 5 × 10 ⁻⁶ Torr or less. Next, nitrogen gas is supplied through the gas supply pipe 34, the variable valve 22 is closed, and the pressure in the vacuum chamber 20 is set to 2 × 10 ⁻³ Torr. Cathode
A negative voltage of 600 V is applied to 28a, and the glass substrate 10 is
The zirconium nitride film 12 is formed on the surface of the glass substrate 10 by moving below the surface 8a.

The surface resistance of the manufactured transparent plate was 2 MΩ / □ or more. The visible light transmittance is 35%, and the non-film surface reflection is 2 反射 visual field C.
With light (JIS Z8729), L ^* = 72.7, a ^* =-4.6, and b ^* = 4.8, indicating a pale yellow-green reflection color.

Example 2 A negative voltage of 500 V was applied to the cathode 28a in the same manner as in Example 1, and a zirconium nitride film having a geometric thickness (physical thickness) d of 180 nm was formed on the surface of the glass substrate. did.

This transparent plate had a surface resistance of 2 MΩ / □ or more.
The visible light transmittance was 23%, and the non-film surface reflection was L ^* = 44.7, a ^* =-2.9, b ^* =-12.2.

Example 3 The pressure in the vacuum chamber 20 was reduced to 5 × 10 ⁻⁶ Torr or less in the same manner as in Example 1 using the apparatus shown in FIG. Next, a mixed gas of nitrogen and argon containing 60% by volume of nitrogen is supplied through a gas supply pipe 34, the variable valve 22 is closed, and the pressure in the vacuum chamber 20 is set to 2 × 10 ⁻³ Torr. A negative voltage of 500 V is applied to the cathode 28a, and the glass substrate is moved below the cathode 28a.

This results in a geometric thickness d on the surface of the glass substrate.
A 58 nm zirconium nitride film was formed. The surface resistance of this transparent plate was 652 kΩ / □. The visible light transmittance is 32.
%, Non-film surface reflection is L ^* = 67.6, a ^* =-
4.6, b ^* = 28.6, which was a bronze reflection color.

Example 4 A zirconium nitride film having a geometric thickness d of 33 nm was formed on the surface of a glass substrate in the same manner as in Example 3. However, the gas atmosphere used was a mixed gas of nitrogen and argon containing nitrogen at a ratio of 30% by volume.

The surface resistance of the manufactured transparent plate was 1300 Ω / □.
In addition, the visible light transmittance was 30%, and the non-film surface reflection was L ^* = 49.0, a ^* =-0.5, b ^* =-13.2 in C light of 2 [deg.] Field of view, which was a blue reflection color.

Example 5 As shown in FIG. 4, a zirconium nitride film 52 having a geometric thickness d of 33 nm and an optical thickness nd were formed on the surface of a glass substrate 50.
A titanium oxide film 54 of 25 nm was formed.

Again, the sputtering apparatus shown in FIG. 3 was used. First, a Zr target 38a is placed on the lower surface of the cathode 28a, and the cathode 28b
The Ti target 38b is attached to the lower surface of the. Then, similarly to the first embodiment, the pressure in the vacuum chamber 20 is reduced to 5 × 10 ⁻⁶ Torr or less. Next, a mixed gas of nitrogen and argon containing 30% by volume of nitrogen was introduced from a gas supply pipe 34, and a variable valve 22 was used.
Is closed, and the pressure in the vacuum chamber 20 is set to 2 × 10 ⁻³ Torr. A negative voltage of 500 V is applied to the cathode 28a, and the glass substrate is moved under the cathode 28a to form the first zirconium nitride film.
Form as a tank.

Then, the power of the cathode 28a is turned off, the variable valve 22 is opened, and the pressure is again reduced to 5 × 10 ⁻⁶ Torr or less.
Is closed, and the pressure in the vacuum chamber 20 is set to 2 × 10 ⁻³ Torr. Next, a negative voltage of 500 V is applied to the cathode 28b, and the glass substrate is moved under the cathode 28b to form a titanium oxide film as a second layer on the zirconium nitride film.

The parallel resistance value of the manufactured transparent plate was 1300Ω / □.
Visible light transmittance is 33%, non-film surface reflection is L at 2 ° field of view C light
^* = 56.2, a ^* =-2.4, b ^* =-11.3, which was a blue reflection color.

Embodiment 6 As shown in FIG. 5, a titanium oxide film 62 having an optical thickness nd of 25 nm, a zirconium nitride film 64 having a geometric thickness d of 33 nm, and an optical thickness A titanium oxide film 66 having an nd of 50 nm was formed.

The sputtering apparatus is as shown in FIG. First, a Zr target 38a is placed on the lower surface of the cathode 28a, and the cathode 28b
The Ti target 38b is attached to the lower surface of the. Then, similarly to the first embodiment, the pressure in the vacuum chamber 20 is reduced to 5 × 10 ⁻⁶ Torr or less. Oxygen gas is introduced from the gas supply pipe 34, the variable valve 22 is closed, and the pressure in the vacuum chamber 20 is set to 2 × 10 ⁻³ Torr. Next, a negative voltage of 500 V is applied to the cathode 28b, and the glass substrate is moved below the cathode 28b to form a titanium oxide film as a first layer on the glass substrate.

Next, the power of the cathode 28b is turned off, and the variable valve 2
2 is opened, the pressure is reduced again to 5 × 10 ⁻⁶ Torr or less, a mixed gas of nitrogen and argon containing 30% by volume of nitrogen is introduced from the gas supply pipe 34, the variable valve 22 is closed, and the vacuum layer is closed.
The pressure inside 20 is set to 2 × 10 ^-3 Torr. 500V for cathode 28a
The negative voltage is applied to move the glass substrate under the cathode 28a to form a zirconium nitride film as a second layer on the titanium oxide film.

The power of the cathode 28a is turned off, the variable valve 22 is opened, the pressure is reduced again to 5 × 10 ⁻⁶ Torr or less, oxygen gas is introduced from the gas supply pipe 34, the variable valve 22 is closed, and the pressure in the vacuum chamber 20 is reduced. 2 × 10 ^-3 Torr. Next, a negative voltage of 500 V is applied to the cathode 28b, and the glass substrate is moved under the cathode 28b to form a titanium oxide film as a third layer on the zirconium nitride film.

The parallel resistance value of the manufactured transparent plate was 1300Ω / □.
Visible light transmittance is 37%, non-film surface reflection is 2 ° C
^* = 60.3, a ^* =-5.7, b ^* =-1.3, which was a green reflection color.

In the above embodiment, a direct current sputtering method was used for film formation. This method does not require matching such as high-frequency sputtering, and has a large film-forming speed, which is advantageous in terms of cost, and is therefore preferable.

SnO ₂ , Al ₂ O ₃ , ZnO, Bi ₂ O ₃ , ZrO ₂ , Ta ₂ O
₅ , Nb ₂ O ₅ , AlN, etc., but TiO ₂ ,
ZrO ₂ , Ta ₂ O ₅ , and Nb ₂ O ₅ are preferred.

[Effect of the Invention] As described above, the present invention provides a glass substrate containing 30% by volume of nitrogen.
Since the zirconium nitride film is formed by direct current sputtering in a mixed gas atmosphere of nitrogen and a rare gas or in a nitrogen gas atmosphere of 100% nitrogen, the surface resistance value becomes 1000Ω / □ or more, and the incident TV wave In this case, the return loss is large, and the occurrence of a ghost failure can be prevented. In addition, it can exhibit reflection colors such as blue and green, and can exhibit excellent architectural design and heat radiation characteristics.

[Brief description of the drawings]

FIG. 1 shows nitrogen-sputtered zirconium nitride films.
FIG. 2 is a graph showing the relationship between the nitrogen concentration and the surface resistance in an argon mixed gas atmosphere, FIG. 2 is a cross-sectional view showing one embodiment of the transparent heat ray reflective glass according to the present invention, and FIG. 3 is suitable for carrying out the present invention. FIG. 2 is an explanatory diagram of a simple DC sputtering apparatus. 4th
FIG. 5 is a sectional view showing another embodiment of the present invention. FIG. 6 is an explanatory diagram of a model of radio wave incidence on transparent heat ray reflective glass, and FIG. 7 is an equivalent circuit diagram thereof. 10, 50, 60 ... glass substrate, 12, 52, 64 ... zirconium nitride film, 54, 62, 66 ... titanium oxide film.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03C 17/00-17/44 C23C 14/14 C23C 14/34-14/46

Claims (4)

(57) [Claims] 1. A radio frequency reflection suppression method comprising: forming a zirconium nitride film on a surface of a glass substrate by direct current sputtering in a mixed gas atmosphere of nitrogen and a rare gas containing nitrogen in a proportion of 30% by volume or more. Method of manufacturing transparent heat ray reflective glass. 2. A method for producing a radio-reflection-suppressing transparent heat ray reflective glass, comprising forming a zirconium nitride film on a surface of a glass substrate by direct-current sputtering in a 100% nitrogen gas atmosphere. 3. A radio-reflection-suppressing transparent heat ray reflective glass having a zirconium nitride single-layer film having a geometric thickness d of 10 nm ≦ d ≦ 200 nm formed on the surface of a glass substrate by the method of claim 1 or 2. 4. The method according to claim 1, wherein a transparent dielectric film and a zirconium nitride film formed by the method according to claim 1 are formed on a surface of the glass substrate.
A layer film is formed, and the optical thickness nd of the transparent dielectric film is 5n in total.
A radio-reflection-suppressing transparent heat ray reflective glass in which m ≦ nd ≦ 300 nm and the total geometric thickness d of the zirconium nitride film is 10 nm ≦ d ≦ 200 nm.