JP2000344547A - Production of base plate having transmissibility to radio waves and wavelength selectivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a base plate effective in transmissibility to radio waves and visible light and reflects solar heat beams by, after applying an AlN layer on the heated surface of a glass substrate or on a glass substrate, then heating the resulting surface, forming an Ag layer being a continuous layer by a sputtering method or the like and changing the formed layer to the Ag-layer comprising particulate Ag. SOLUTION: An Ag-layer being a continuous layer is obtained by heating the surface of a glass substrate which is coated with a transparent dielectric layer other than AlN or coated with an AlN layer and forming the continuous Ag film by a sputtering method, a CVD method, a thermal spraying method, a vacuum deposition method or an ion-plating method, and the Ag-layer comprising particulate Ag is formed by changing the formed Ag-layer. At this time, the heat treatment is preferably carried out at a temp. of about 100 to 500 deg.C and for about 5 to 180 min. The preferable method for forming film is the sputtering method from viewpoints of uniformity in Ag particle size and productivity. It is possible to further coat the AlN-layer on the Ag-layer comprising particulate Ag.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can efficiently transmit radio waves and visible light arriving at windows of buildings, automobiles, etc., and exhibit sufficient heat insulation by reflecting the heat rays of the sun. The present invention relates to a wavelength selection substrate that can be used.

[0002]

2. Description of the Related Art In recent years, window glasses which are coated with a conductive thin film or pasted with a film containing a conductive thin film for the purpose of shielding solar radiation have begun to spread. When such a window glass is applied to a high-rise building, radio waves in the TV frequency band are reflected, causing a ghost on a TV screen and making it difficult to receive satellite broadcasts with an indoor antenna. In addition, when used as a window glass for a house or a window glass for an automobile, it may be difficult for a cellular phone to be connected, or the gain of a glass antenna may be deteriorated.

Under such circumstances, at present, a glass substrate is coated with a transparent heat ray reflective film having a relatively high electric resistance.
It has been practiced to partially prevent the transmission of visible light and reduce the reflection of radio waves to prevent radio interference.

In the case of glass with a conductive film, the length of the conductive film parallel to the direction of the electric field of the incident radio wave is set to be less than 1/20 times the wavelength of the radio wave. Japanese Patent Application Laid-Open No. 2620456 discloses that the signal is divided so as to prevent radio interference.

[0005]

However, the conventional method of coating a transparent heat ray reflective film having a relatively high electric resistance can reduce the reflection of radio waves and prevent radio wave interference, but the heat ray shielding performance can be reduced. Was not enough and there was a problem in the comfort of life. Further, in the method of dividing the conductive film disclosed in Japanese Patent No. 2620456, the length of division is much larger than the wavelengths of visible light and near-infrared light that occupy most of sunlight. Are all reflected,
Although a radio wave transmitting wavelength-selective screen glass having sufficient solar radiation shielding performance while preventing radio wave interference can be obtained, there is a problem that the transmission of visible light cannot be ensured. Further, in a window having a large opening such as 2 m × 3 m, for example,
To transmit satellite broadcast waves, the wavelength of satellite
1/20 of 5 mm, at least the conductive film must be cut into 1.25 mm square, preferably 0.5 mm square. Cutting a large-area conductive film into such small segments with, for example, an yttrium-aluminum-garnet laser requires a long time and is not practical.

[0006]

First, the present inventors disclosed in Japanese Patent Application No. 11-90597 a method in which a sputtered film was formed on the surface of a glass substrate or a surface of a glass substrate coated with an AlN layer (aluminum nitride layer). Ag consisting of a continuous layer by the method
After the layer is formed, heat treatment is performed to obtain granular Ag.
An application was made for a radio wave transmitting wavelength selective glass in which an Ag layer changed and generated was laminated. After various studies,
The granular Ag layer is not limited to a method in which a continuous Ag layer is formed and then heat-treated. The AlN layer (aluminum nitride layer) is coated on a heated glass substrate or a glass substrate, and then the substrate is coated with a continuous layer on the substrate surface. It has been found that a good radio wave transmitting wavelength selective substrate can be obtained even if the Ag layer is changed into a granular Ag layer by forming a film, and the film formation is not limited to the sputtering method, and other film forming methods can be applied. Thus, the present invention has been accomplished.

The present invention reduces the reflectivity of radio waves in the frequency bands of TV broadcasts, satellite broadcasts, and mobile phones to prevent radio interference, and has sufficient solar shading performance and visible light transmittance. It is an object of the present invention to provide a radio wave transmitting wavelength selecting substrate.

That is, the method for manufacturing a radio wave transmitting wavelength selective substrate according to the present invention comprises the steps of: applying a sputtering method, a CVD method to a heated glass substrate surface, or coating an AlN layer (aluminum nitride layer) on a glass substrate and then heating the surface. The method is characterized in that an Ag layer formed of a continuous layer is formed by any one of a method, a thermal spraying method, a vacuum evaporation method, and an ion plating method to thereby change and generate an Ag layer formed of granular Ag. .

On the surface of the granular Ag layer obtained above, an Ag layer composed of a second continuous layer is further formed and then heat-treated to form an Ag layer composed of the second continuous layer. It can be changed into a granular Ag layer.

Further, the method for producing a radio wave transmitting wavelength selective substrate according to the present invention is characterized in that a CVD method is applied to a surface of a glass substrate or a surface of a glass substrate coated with an AlN layer (aluminum nitride layer).
An Ag layer consisting of a continuous layer is formed by any one of the following methods, a thermal spray method, a vacuum evaporation method, and an ion plating method.
It is characterized in that it is changed and generated in an Ag layer composed of.

Furthermore, an aluminum nitride layer can be further coated on the Ag layer made of granular Ag.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The radio wave transmitting wavelength selective substrate of the present invention is an Ag having a structure in which granular Ag is dispersed on the surface of a heat resistant substrate such as glass or the surface of a substrate coated with a transparent dielectric layer. It is formed by coating a layer.

As a typical method for forming a granular Ag layer, for example, the following two methods can be used.

The first method is to form a continuous Ag layer on the surface of a substrate coated with a transparent dielectric layer other than AlN (aluminum nitride), and then heat-treat the Ag layer.
It can be produced by changing Ag in the Ag layer composed of Ag of the continuous layer into granular Ag. Granular Ag obtained by such a method has the advantages of a large particle size, excellent crystallinity, and high electrical conductivity within the particles. Therefore, characteristics such as high heat ray reflection characteristics can be expected. Good and preferable.

The second method is to use a heated AlN
By forming an Ag layer consisting of a continuous layer on the surface of a transparent substrate covered with a transparent dielectric layer excluding (aluminum nitride), it can be immediately changed into an Ag layer consisting of granular Ag. Granular Ag obtained by such a method
Is preferred because the particle size becomes uniform and characteristics such as excellent wavelength selectivity are improved.

A continuous Ag layer is formed on the surface of the transparent substrate covered with the transparent dielectric layer except for the heated AlN (aluminum nitride), so that the Ag is immediately changed into granular Ag. Forming an Ag layer comprising a second continuous layer on the surface thereof and performing a heat treatment on the Ag layer.
Can be changed into a granular Ag layer, and this method is particularly preferable because a granular Ag having a uniform particle size and a large particle size can be obtained. The substrate temperature when forming the Ag layer composed of the second continuous layer is not particularly limited, but is preferably around room temperature in order to make Ag particles coarse.

The heat treatment temperature is 100 ° C. to 5 ° C.
00 ° C., the holding time is preferably about 5 to 180 minutes,
It is not particularly limited to this range in order to obtain the desired particle size.

Although the details of the mechanism by which the above-mentioned heat treatment is performed to change the continuous Ag layer into a granular Ag layer are unknown, the silver film deposited by the sputtering method has a high surface energy. It is considered that by applying heat energy, the particles are dispersed in a particle state and a stable state with low surface energy is obtained.

A method for forming a continuous Ag layer is as follows.
The sputtering method, the vacuum evaporation method, the CVD method, the thermal spray method, the ion plating method and the like are not particularly limited, but the sputtering method is particularly preferable in terms of uniformity of Ag particles to be produced and productivity.

The transparent substrate is not particularly limited as long as it has heat resistance, but a glass substrate is particularly preferable in terms of transparency, heat resistance and the like.

The transparent dielectric film excluding AlN of the present invention may be a transparent nitride film such as Si ₃ N ₄ , SiAlN or the like.
iO _x N _y, a transparent oxynitride film such as TiO _x N _y is preferred. In addition, as the transparent oxynitride film, Cr,
A metal oxynitride made of at least one kind of metal element such as Zn, Zr, Sn, and Ta can also be used. Also, S
A transparent metal oxide composed of at least one metal element such as i, Ti, Cr, Zn, Zr, Sn, and Ta can be used. In that case, however, before depositing the outermost transparent oxide film, In addition, a metal sacrificial layer for preventing oxidation of silver fine particles needs to be deposited in a thickness of several angstroms to several tens angstroms.

The obtained wavelength-selective substrate reduces the reflectivity of radio waves in the frequency bands of TV broadcasting, satellite broadcasting, and cellular phones to prevent radio interference, and has sufficient solar shading performance and visible light. It is a radio wave transmitting wavelength selecting substrate having transparency.

The reflectance (Rdp) of the wavelength selective glass is:
It can be calculated from the shape of silver by a theoretical formula as shown by the following formula (1). (This theoretical formula is expressed by the present inventor as Journal of Applied Physs.
ics Volume 84, Number 11,
6285-8290 (1998). )

[0024]

(Equation 1)

Here, Rdp: reflectance λ: wavelength [nm] AR: area ratio occupied by silver fine particles Rms: reflectance of silver multilayer film having silver layer thickness D D: silver layer thickness [nm] Esg A division coefficient (reflection of a system in which the ratio of the length of a square segment composed of perfect conductors arranged infinitely repeatedly on a glass substrate or a dielectric film to the wavelength of incident light is Li / λ, and the area ratio occupied by the segment is AR) Ratio) Li: particle size of silver fine particles [nm] Sr: area ratio of silver fine particles of particle size Li ni: number of silver fine particles of particle size Li The reflectance (Rdp) of the wavelength selective glass of the present invention is as follows.
The following formulas (2) to (1) show that it can be calculated from the shape of silver by the theoretical formula shown by the above formula (1).
This will be described in 3).

Hereinafter, a method of deriving an electrical integral equation for calculating the reflectance of a system in which perfect conductor segments are periodically fixed on a dielectric substrate will be described step by step. First, a method of obtaining the division coefficient Esg using a theoretical formula will be described.

(1) Induced Current Distribution In the following calculations, it is assumed that radiation from the conductor segments and the dielectric substrate induces an electromagnetic field.

FIG. 1 geometrically shows the state of the periodic array and the electromagnetic waves discussed here. An infinite periodic array of each of the x-axis and y-axis periodic units a and b is fixed on a dielectric substrate. The thickness of the substrate is d and the dielectric constant is εr. It is assumed that an incident plane wave having an electric field intensity Ei propagated from the (θi, φi) direction irradiates the frequency selection screen. α is (θi, φi)
This is the polarization angle in the plane.

[0029]

(Equation 2)

Here, r is a position vector, and ki is a propagation vector of an incident wave (a wave number vector indicating a propagation constant in a traveling direction of an electromagnetic wave).

It is assumed that the current Jc is induced on the conductor surface by the incident wave. This current is proportional to the phase of the incident wave. And since the structure is periodic, the current can be Fourier series expanded. Therefore, the current distribution can be expressed as follows.

[0032]

(Equation 3)

[0033]

(Equation 4)

Since the electromagnetic field generated by the scattered wave from the conductor and the electromagnetic field generated by the scattered wave from the dielectric surface are handled by a single electromagnetic field, the equivalent current Ji induced on the dielectric substrate surface is equivalent. The magnetic current Mi is defined as follows.

[0035]

(Equation 5)

A conductor of any shape can be electrically approximated by a wire segment. The current distribution is divided sinusoidally (PW
S) It can be represented by a function.

[0037]

(Equation 6)

[0038]

Equation 7

(2) Radiation field (reflection electric field and reflection magnetic field) The electric field emitted by the induced magnetic current and induced current on the surface of the scatterer is called a reflected electric field. This reflected electric field can be expressed by Expression (8) using a Green function.

[0040]

(Equation 8)

(3) Power reflectivity

[0042]

[Equation 9]

[0043]

(Equation 10)

[0044]

[Equation 11]

The method for obtaining the division coefficient Esg has been described above. Next, the particle size distribution (the particle size, area ratio, and number of silver particles) of equation (1) is determined.

(4) Average particle size of silver particles

[0047]

(Equation 12)

The average particle size (l) of the silver particles can be calculated as follows.

[0049]

(Equation 13)

As described in Reference Example 2 below, in order to secure a shielding efficiency in the near infrared region of 0.3 or more, the average particle size of silver particles is 10 nm or more and the thickness of silver particles is 5 nm or more. Is preferred. The silver particles had a particle size of 0.5
If the distance is not less than mm, a problem of radio interference occurs, which is not preferable. Next, a method of obtaining the reflectance from the above-described division coefficient Esg and the particle size distribution will be described.

(5) The reflectivity of the AlN-based system in which silver is dispersed
The reflectance of the theoretical Ag layer is affected by the plasma vibration of silver atoms. Therefore, the reflectance (Rdp) of the AlN layer in which silver is dispersed
Depends on the surface resistivity (Rsq), the wavelength (λ) of the incident wave, and the silver particle size. The effect of the particle size on Rdp is determined by the division factor (E
sg).

The theoretical value of the reflectance of a system in which square segments of a perfect conductor are periodically fixed on an AlN layer having a thickness of 40 nm is defined as Esg. The theoretical value is calculated using equation (11). This coefficient depends on L / λ and the area ratio (AR). L / λ is the ratio between the size of the segment (corresponding to the particle size of the silver particles) and the wavelength of the incident light shown in FIG.
Incidentally, FIG. 2 is a diagram showing the ratio of the wavelength of the AR = 2 ^{2/3 2} of division factor (Esg) and L / lambda (segment size and the incident light.

AR is L / a, that is, the ratio of the area of the segment to the area of the unit cell (minimum repeating unit) shown in FIG. Despite AR = 2/3 (= 0.444), Esg in FIG. 2 approaches 1.0 with L / λ = 0.525. This is because when the Rsq. Of the conductor and the dielectric loss factor of the substrate are negligibly small, the energy of the incident wave is all converted to the induced current on the unit cell at the resonance frequency. Assuming that Rdp is equal to the product of Rms and Esg, formula (1) for finding Rdp is proposed. Rms is AlN
(30 nm) / Ag (Dnm) / Reflectance of AlN (10 nm) multilayer film. D is the average thickness of the Ag particles.

[0054]

(Equation 1)

Here,

[0056]

(Equation 14)

Here, ARo is the ratio of silver particles to the total area of the thin film.

Rms is a function of Rsq and λ. And E
Since sq depends on L / λ, equation (1) shows that Rdp is Rsq,
It is shown that it depends on λ and L. The term Σ depicts the effect of silver particle size distribution on Rdp. As shown in FIG. 2, since the change of Esq with respect to the increase of L / λ is nonlinear, the term of Σ is necessary.

Since the total weight of Ag in the AlN layer is kept constant during the heat treatment of the Ag layer, D and L can be expressed by equations (1) and (14).

[0060]

(Equation 15)

[0061]

(Equation 16)

Where Lm is the average length of the segment,
D0 is the thickness of the Ag layer in the multilayer film immediately after film formation.

Ag has a plasma frequency in the ultraviolet region, and further, there is a region called "silver window" where the extinction coefficient of Ag is infinitely small on the low frequency side. By controlling the thickness of the particles and the thickness of the dielectric interference film, the transmittance of visible light can be secured.

The Ag film changes to a state of being dispersed in particles by heating. This particle size is much smaller than the above-mentioned 0.5 mm. By controlling the thickness of the Ag film, heat treatment conditions, and the like, a glass that selectively reflects near infrared rays can be obtained.

Hereinafter, examples of the specification filed by the present inventors will be shown as reference examples.

[0066]

REFERENCE EXAMPLE Reference Example 1 A radio wave transmitting wavelength selective glass was formed by a DC magnetron sputtering method. Before sputtering, the vacuum chamber was evacuated to 2 × 10 ⁻⁴ Pa. During sputtering, the distance between the target and the glass substrate was fixed at 90 mm. The lowermost AlN layer is a pure Al target (diameter 129).
mm, and a thickness of 10 mm). In addition, in order to prevent abnormal discharge, the frequency 10 k
Hz rectangular pulse wave was applied to the cathode. During sputtering, the pressure of the mixed gas was controlled at 0.7 Pa by a method of adjusting the N ₂ / Ar gas flow ratio to 20/80. Using a pure Ag target (diameter 129 mm, thickness 5 mm) at an argon gas pressure of 0.7 Pa, the intermediate layer A
A g layer was deposited. Before stacking the uppermost AlN layer, the AlN / Ag layer immediately after film formation is placed in a sputtering vacuum chamber at 2 × 10 ^-4 P
a, Heat treatment was performed at 200 ° C. The uppermost AlN layer is formed by the same method as the lowermost AlN layer by using a pure Al target (diameter 129 mm, thickness 10 m).
m) and deposited by reactive sputtering.

The sample composed of the glass substrate / AlN layer / Ag layer after the above-mentioned steps or the above was measured for the particle size distribution of silver particles by the following method.

A. The state of the surface of the sample composed of the glass substrate / AlN layer / Ag layer after the step of silver particle size distribution was observed with a scanning electron microscope (SEM) using Hitachi S-415. The results are shown in FIG. Table 1 shows the particle size distribution obtained by reading the size of each particle in FIG. 3 by the Martin method.

As a result, the area ratio (defined as the ratio of the area occupied by silver particles to the total area) was 0.20. Particle size (l) in Table 1
And the number (n) were substituted into the expressions (12) and (13), and as a result, the average particle size was 87 nm. The particle size distribution is shown in Table 2 as a function of Sr. Glass substrate after completion of step / Al
As a result of observing the state of the surface of the sample composed of the N layer / Ag layer with an atomic force microscope (AFM) using SPA-250 manufactured by Seiko, the average particle diameter was 168 nm and the area ratio was 0.38. Was.

[0070]

[Table 1]

[0071]

[Table 2]

B. Crystal Orientation The sample composed of the glass substrate / AlN layer / Ag layer which had been subjected to the above steps was evaluated for silver crystal orientation. In addition, the measurement was performed by the X-ray diffraction (XRD) method of RINT-1500 manufactured by Rigaku using characteristic X-rays of CuKα.

As a result, it is shown that the Ag layer in the glass substrate / AlN layer / Ag layer sample immediately after the film formation after completion of the step contains polycrystalline silver having an Ag (111) plane grown parallel to the substrate. I have. When the Ag continuous layer was changed into discontinuous particles as shown in FIG. 3 by performing the heat treatment in the step, the intensity of the diffraction peak on the Ag (200) plane was slightly increased. Table 3 shows that Ag (111)
As a result of the heat treatment in which the plane spacing was 2 hours, 236.6 to 2
35.9 pm. The half width of the peak also tended to decrease.

[0074]

[Table 3]

C. Reflectance The reflectance spectra of the sample immediately after the film formation in which the step was completed and the heat-treated sample in which the step was completed were measured. In addition,
FIG. 4 shows the results of the measurement of the reflection spectrum in the range of 350 to 1800 nm at room temperature using a Hitachi 340 spectrophotometer.

The thickness of the Ag layer is determined from the reflectance curve of the sample immediately after film formation after the completion of the step. As shown in FIG. 5, the theoretical curve of the reflectance calculated by the four-terminal matrix method was in good agreement with the measured value when the thickness of the Ag layer immediately after film formation was 8 nm. FIG. 5 is a diagram showing a comparison of the reflection spectrum between the experimental value (○) and the theoretical value (-) of the sample immediately after film formation. The theoretical values were calculated assuming that the thickness of the Ag layer was 8 nm.

On the other hand, in Table 3, Ag having a heating time of 0 hour was used.
The half-width of the (111) peak is calculated by the equation (17) [Scherr
er's equation], and the thickness of the crystal in the Ag layer immediately after film formation was determined. As a result, the value was 10 nm. The thickness of the Ag layer will be equal to the size of the crystal. That is, A
The g layer indicates that the Ag (111) plane parallel to the substrate is composed of the grown polycrystalline silver.

[0078]

(Equation 17)

Here, CT: thickness of crystal [結晶
Λ: wavelength of irradiated X-ray [Å] Δ (2θ): half width [radian] θ: incidence angle of X-ray [radian] From the reflectance curve of the heat-treated sample after completing the process shown in FIG. It has been shown that heat treatment of the layer increases the reflectivity of incident waves with wavelengths shorter than 780 nm and decreases the reflectivity of incident waves longer than 780 nm. This phenomenon is
This is considered to be due to the dispersion of silver particles having a particle size smaller than the wavelength of the incident wave.

The curve shown in FIG. 6 shows the area average particle diameter of silver fine particles of 130 nm, the thickness of silver particles of 18 nm, and the area ratio of 0.4.
The reflectance of the wavelength selection film of No. 44 is from 350 nm to 180
It is a theoretical curve calculated | required from theoretical formula (1) in the wavelength range of 0 nm. This curve is in good agreement with the values of the embodiment indicated by the black circles in FIG. However, as shown in Table 4, S
The average particle size observed by EM is a value smaller than the theoretical particle size. This difference is caused by underestimating the silver particle size in SEM observation. That is, it is considered that the intensity of the secondary electrons scattered from the base of the particle having a thickness of about 3 nm is weak, and thus the secondary electron cannot be detected as the base of the particle. Also,
As shown in Table 4, the thickness of the silver particles of the silver particles of the silver fine particles coincides with the measured value obtained by X-ray. In this reference example, the validity of the theoretical formula (1) was proved.

[0081]

[Table 4]

Reference Example 2 In Reference Example 1, the validity of the theoretical formula (1) was proved.
From the theoretical value of the equation (1), the shape of the silver fine particles suitable for the wavelength selection film is obtained. First, the shielding efficiency (Es) of the silver particle system is defined by equation (18).

[0083]

(Equation 18)

Here, λ: wavelength of an electromagnetic wave incident on the window glass Rdp: reflectance of glass in which Ag is dispersed Isr: radiation intensity of the sun at an air mass of 1.0 Sr in the formula (1) is various average sizes of the segments (L
AR = 0.444, assuming constant for i)
The maximum shielding efficiency of the silver particle system of D0 = 8 nm is calculated by the equation (1). As shown in FIG. 7, when Li = 375 nm, the shielding efficiency is maximized in the visible light and broadcast wave regions while ensuring the transparency of the insulating glass. FIG. 7 is a diagram showing the shielding efficiency of silver particles and the average size of segments.
Saegihei efficiency, assuming ^{AR = 2 2/3 2,} Li = 18nm, was calculated from the equation (1). FIG. 9 shows a theoretical curve of the reflection spectrum at Li = 375 nm. FIG. 7 is a diagram showing a comparison between a theoretical reflection spectrum (−) at 375 nm and a measured reflection spectrum (●) at Lm = 130 nm in a silver particle-dispersed AlN film. Theoretical values assuming ^{AR = 2 2/3 2,} Li = 18nm, was calculated from the equation (1).

As Lm = Li increases from 130 nm to 375 nm, the position where the reflection becomes maximum shifts to the longer wavelength side. This indicates that a wavelength selection screen that reflects only near-infrared rays can be designed by adjusting the size of silver particles. The theoretical value of the reflectance is 800
It sharply decreases at 5 to 6 places in the wavelength range of nm or less. Since the segments are arranged periodically, in the case of FIG.
At /λ=0.626, the reflectivity sharply decreases.

Next, as a representative example, the dependence of the shielding efficiency in the near-infrared region of the wavelength-selective glass and the transmittance of visible light on the thickness of the silver fine particles when the area average particle size of the silver fine particles is 375 nm is expressed by a theoretical formula (1). ) Are shown in Tables 5 and 6. The area ratio used was 0.444 and 0.826 as representative values.

According to Tables 5 and 6, in order to secure a shielding efficiency in the near infrared region of 0.3 or more, the thickness of the silver fine particles must be 5n.
It is understood that m or more is necessary. On the other hand, when the thickness of the silver fine particles exceeds 30 nm, the shielding efficiency in the near infrared region reaches saturation while transmitting visible light.

The thickness of the silver particle obtained from the Scherrer's equation of the equation (17) is inversely proportional to the half width of the diffraction peak of the (111) plane of Ag. Determined by detection limit. This value is the current X
In a line diffractometer, the angle is about 0.01 degree. Substituting this value into equation (17) results in 1 μm. That is, Sc
The Herrer equation is applicable only when the thickness of the silver particles is 1 μm or less. Therefore, the preferred thickness of the silver fine particles is in the range of 5 nm to 1 μm. The characteristic X-ray wavelength of CuKα is 1.5405 °, and the incident angle of the X-ray corresponding to the (111) plane of Ag is 38.12.2 °.

[0089]

[Table 5]

[0090]

[Table 6]

As a typical example, the silver fine particles have a thickness of 20 nm.
Table 7 and Table 8 show the results obtained by using the theoretical formula (1) to determine the near-infrared region shielding effect and the dependence of the visible light transmittance on the area average particle diameter of the silver fine particles in the case of the above. From Tables 7 and 8, it can be seen that the particle size of the silver fine particles needs to be 100 nm or more in order to secure the shielding effect in the near infrared region of 0.3 or more. The shielding effect increases with an increase in the particle size, but decreases with a certain particle size or more depending on the area ratio. However, the shielding efficiency does not fall below 0.3. However, if the particle size is 1/20 or more of the wavelength of the shortest satellite broadcast wave among the currently used broadcast waves, radio interference becomes a problem (see Patent Registration No. 2620456). The particle size is desirably 0.5 mm or less.

[0092]

[Table 7]

[0093]

[Table 8]

[0094]

An embodiment of the present invention will be described below. However,
The present invention is not limited to this.

Example 1 A radio wave transmitting wavelength selective glass was formed by a magnetron sputtering method. Before sputtering, the vacuum chamber was evacuated to 2 × 10 ⁻⁴ Pa. During sputtering, the distance between the target and the glass substrate was fixed at 90 mm. The lowermost AlN layer is made of an Al target (having a diameter of 76 m).
m, thickness 5 mm) using DC reactive sputtering. N ₂ gas was used as the reactive gas, and the pressure was adjusted to 1.0 P by adjusting the N ₂ gas flow rate during sputtering.
a. Heat the glass substrate / AlN layer in a vacuum chamber at 250 ° C
Held in. Ag was deposited on a glass substrate maintained at 250 ° C. using a pure Ag target (diameter: 76 mm, thickness: 5 mm) under an argon gas pressure of 1.0 Pa. The AlN layer as the uppermost layer is made of an Al target (diameter: 76 mm, thickness: 5 mm) in the same manner as the lowermost AlN layer.
Was deposited by DC reactive sputtering.

With respect to the sample composed of the glass substrate / AlN layer / Ag / AlN layer after the above steps, the radio wave transmission, the average particle diameter of silver particles, the average thickness and the reflectance were measured by the following methods. Was.

A. Radio wave permeability Surface resistivity (Ω / sq) of the sample composed of the glass substrate / AlN layer / Ag layer / AlN layer after the above process
The surface resistance measurement device (MEGARESTA H070
As a result of the measurement in 9), it is 9.9 × 10 ¹² Ω / sq or more,
Radio wave transmission is satisfactory enough.

B. Particle Size Distribution of Silver Particles The state of the surface of the sample composed of the glass substrate / AlN layer / Ag layer which has been subjected to the above-mentioned steps is shown by S-4 manufactured by Hitachi, Ltd.
Field emission scanning electron microscope (FE-SE)
M), and the image was analyzed using Image-ProPLUS, an image analysis software manufactured by Cybemetics. As a result, the average particle diameter was 335 nm and the area ratio was 0.78.

C. Average Thickness of Silver Particles The orientation of the silver crystal of the sample composed of the glass substrate / AlN layer / Ag layer / AlN layer after the above-described steps was determined by Cu
The characteristic X-ray of Kα was measured by an X-ray diffraction (XRD) method of RINT-1500 manufactured by Rigaku. Based on the result, Ag
The half-width of the (111) peak is calculated by the equation (17) [Scherr
er's equation] and the thickness of the crystal in the Ag layer immediately after the film formation was determined. The result was 27 nm.

[0100]

(Equation 17)

Here, CT: thickness of crystal [結晶
Λ: wavelength of irradiated X-rays [Å] Δ (2θ): half-width [radian] θ: incident angle of X-rays [radian] D. Reflectance The reflection spectrum of the sample which has completed the above process is U- The measurement was performed in the range of 340 nm to 1800 nm using a 4000 type self-recording spectrophotometer. As a result, Ag is deposited on the heated substrate to form fine particles, so that the reflectance at a wavelength of 850 nm is 80, as shown in FIG.
% And a very high value.

Example 2 A radio wave transmitting wavelength selective glass was formed by a magnetron sputtering method. Before sputtering, the vacuum chamber was evacuated to 2 × 10 ⁻⁴ Pa. During sputtering, the distance between the target and the glass substrate was fixed at 90 mm. The lowermost AlN layer is made of an Al target (having a diameter of 76 m).
m, thickness 5 mm) using DC reactive sputtering. During sputtering, the pressure was controlled at 1.0 Pa by adjusting the N ₂ gas flow rate. Heat the glass substrate / AlN layer in a vacuum chamber at 250 ° C
Held in. Using a pure Ag target (diameter: 76 mm, thickness: 5 mm) under an argon gas pressure of 1.0 Pa, an Ag first layer was deposited on a glass substrate maintained at 250 ° C. After depositing the Ag first layer, the glass substrate temperature was cooled to room temperature. After cooling to room temperature, a second Ag layer was deposited under the same sputtering conditions as the first Ag layer. Immediately after forming the Ag second layer, the glass substrate / Ag first layer / A
g The second layer is placed in a sputtering tank at 2 × 10 ⁻⁴ Pa, 20
Heat treatment was performed at 0 ° C. for 2 hours. The AlN layer as the uppermost layer is made of an Al target (diameter: 76 mm, thickness: 5 mm) by the same method as the lowermost AlN layer.
Was deposited by DC reactive sputtering.

For the sample composed of the glass substrate / AlN layer / Ag first layer / Ag second layer / AlN layer after the above steps, the radio wave transmission, the average particle size of silver particles, The average thickness and the reflectance were measured.

A. Radio Wave Transmittance As a result of measuring the surface resistivity (Ω / sq) of the sample composed of the glass substrate / AlN layer / Ag first layer / Ag second layer / AlN layer after the above-mentioned steps, 9 .9 × 10 ^{1 2} Ω / sq
As described above, the radio wave transmittance is sufficiently satisfied.

B. Average Particle Size of Silver Particles The state of the surface of the sample composed of the glass substrate / AlN layer / Ag first layer / Ag second layer after the above-mentioned steps is
In the same manner as in Example 1, a field emission scanning electron microscope (FE) was used.
-SEM), and the image was analyzed. As a result, the average particle diameter was 350 nm and the area ratio was 0.74.

C. Average Thickness of Ag Particles The orientation of the silver crystal of the sample composed of the glass substrate / AlN layer / Ag first layer / Ag second layer / AlN layer after the above process was completed was measured by RINT-RINT- X-ray diffraction of 1500 (X
RD) method. Based on the result, Ag (11
1) The half-width of the peak was substituted into the equation (17), and the thickness of the crystal in the Ag layer immediately after the film formation was obtained.
Met.

D. Reflectance The reflection spectrum of the sample after completing the above-mentioned steps was
The measurement was performed in a range from 0 nm to 1800 nm. as a result,
The first Ag layer is deposited on the heated substrate and then cooled,
10g by depositing a second layer film and performing a heat treatment.
As shown in the figure, the reflectance at a wavelength of 950 nm is 73%.
And very high values. As described above, the reflectance is maximized on the long wavelength side because uniform Ag fine particles serving as nuclei are formed by depositing the Ag first layer on the heated substrate,
Further, it is considered that the Ag nucleus is coarsened by depositing a second Ag layer thereon and performing a heat treatment.

[0108]

According to the present invention, the reflectance of radio waves in the respective frequency bands of TV broadcasting, satellite broadcasting, and portable telephones is reduced, and sufficient solar shading performance and visible light transmission are provided. It is possible to live a comfortable life without causing radio interference such as generation of a ghost, loss of communication with a mobile phone, or deterioration of the gain of a glass antenna, and sufficient shielding of solar radiation.

[Brief description of the drawings]

FIG. 1 shows a geometrical drawing of a scatterer.

[Figure 2] AR = ² 2/3 2 of the division factor (Esg) and L / λ
FIG. 6 is a diagram illustrating a relationship between (segment size and wavelength ratio of incident light).

FIG. 3 is a view showing a SEM micrograph of a silver-dispersed AlN layer.

FIG. 4 is a diagram showing reflectance before and after heat treatment.

FIG. 5 is a diagram showing a comparison between an experiment (○) and a theoretical (−) reflection spectrum of a sample immediately after film formation.

FIG. 6 is a diagram showing a comparison between an experimental value (●) and a theoretical value (−) of the reflection spectrum of a silver-dispersed AlN film.

FIG. 7 is a diagram showing a relationship between a shielding effect of a silver particle system and an average size of a segment.

FIG. 8 is a diagram showing a comparison between a theoretical reflection spectrum (−) at Lm = 375 nm and a measurement reflection spectrum (●) at Lm = 130 nm in a silver particle-dispersed AlN film.

FIG. 9 is a reflection characteristic diagram of the radio wave transmitting wavelength selective glass in Example 1.

FIG. 10 is a reflection characteristic diagram of the radio wave transmitting wavelength selective glass in Example 2.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masanobu Konan 1-47-9 Kitayama, Hirakata-shi, Osaka F-term (reference) 4G059 AA01 AC06 AC30 DA01 DB01 EA12 EB04 GA01 GA02

Claims (4)

[Claims] 1. A sputtering method, a CVD method, a thermal spraying method, a vacuum evaporation method, an ion plating method, on a heated glass substrate surface or on a heated surface after coating an AlN layer (aluminum nitride layer) on the glass substrate. A method for producing a radio wave transmitting wavelength selective substrate, characterized in that an Ag layer made of a continuous layer is formed by any one of the methods described above to thereby change into an Ag layer made of granular Ag. 2. The method according to claim 2, further comprising the step of:
2. The radio wave transmittance according to claim 1, wherein the Ag layer formed of the second continuous layer is formed into a granular Ag layer by heat treatment after forming the Ag layer formed of the continuous layer. A method for manufacturing a wavelength selection substrate. 3. The method according to claim 1, wherein A is on the surface of the glass substrate or on the glass substrate.
The surface coated with the 1N layer (aluminum nitride layer) is coated with a CVD method,
An Ag layer consisting of a continuous layer is formed by any one of a thermal spraying method, a vacuum evaporation method, and an ion plating method, and then heat-treated to be changed into an Ag layer consisting of granular Ag. A method for producing a radio wave transmitting wavelength selective glass, comprising: 4. The method according to claim 1, wherein a transparent dielectric layer is further coated on the Ag layer made of granular Ag.
A method for producing the radio wave transmitting wavelength selective substrate according to the above.