JPH0423633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a heat ray shielding laminate, particularly an improved heat ray shielding layer that prevents the occurrence of color unevenness due to interference between multilayer films and allows the transmittance in the visible range to be set to an arbitrary value. Relating to a shielding laminate.

BACKGROUND ART A visible light transmitting substrate, such as a glass plate or a plastic plate, usually has good visible light transmittance, but on the other hand, it also has good transmittance to light rays with wavelengths longer than the visible region (infrared rays). For this reason, it has become necessary to process the energy of the heat rays transmitted through the substrate by appropriate means.

For example, when this type of substrate is used for automobile glass, there are problems such as an increase in indoor temperature due to sunlight, which has the disadvantage of requiring a large-capacity cooling device.

For this reason, it has conventionally been put into practical use that this type of substrate is coated with a predetermined coating to reflect or absorb heat rays and shield them. For example, on a transparent substrate such as glass or plastic, a high refractive index transparent dielectric thin film layer made of TiO ₂ or CeO ₂ with a thickness that satisfies infrared reflection conditions, and a SiO ₂ film with a thickness of approximately A heat ray shielding laminate in which low refractive index transparent dielectric thin film layers made of , MgF ₂ or CeF ₃ are alternately laminated is well known, and this laminate has excellent visible light transmittance and heat ray reflection properties. It is widely used in automobile and building window glass and other applications.

However, in such conventional heat ray shielding laminates, color unevenness occurs due to light interference in the multilayer film laminated on the surface of the substrate, and when the laminate is used as a film on glass for automobiles and buildings, Reflected light causes light pollution to the surrounding environment, and furthermore, the discoloration of the glass surface causes discomfort to people nearby, and effective countermeasures have been desired.

Additionally, approximately 50% of the solar thermal energy that is subject to heat ray shielding exists in the visible range and 50% in the infrared range. Therefore, improving the visible light transmittance of the heat ray shielding laminate leads to an increase in the penetration of thermal energy into the interior through the half glass substrate.

However, although conventional heat ray shielding laminates efficiently shield thermal energy in the infrared region, most of the thermal energy in the visible region is transmitted through them, which has the drawback of limiting their heat ray shielding properties.

In particular, in recent years there has been a very active movement to reduce the heat load by shielding as much as possible the solar heat energy that enters through the window glass of automobiles and buildings, but with conventional heat ray shielding laminates, As explained above, there is a limit to the heat ray shielding effect, and effective countermeasures have been desired.

Purpose of the Invention The present invention was made in view of the above-mentioned conventional problems, and its purpose is to prevent the occurrence of color unevenness due to interference in multilayer films, and to adjust the visible light transmittance to any value depending on the purpose of use. The object of the present invention is to provide a heat ray shielding laminate that can be set to a value of .

Structure of the Invention The laminate of the present invention has high refractive index thin film layers and low refractive index thin film layers made of a visible light transparent material alternately laminated on the heat source side surface of a visible light transparent substrate, and the outermost thin film layer is characterized by forming a low refractive index thin film layer, adding a predetermined metal to the low refractive index thin film layer, and setting the visible light transmittance to an arbitrary value.

As described above, according to the present invention, by adding a predetermined metal to the low refractive index thin film layer, while maintaining the interference reflection characteristics in the infrared region, the transmittance in the visible region can be adjusted to any value depending on the purpose of use. It becomes possible to set.

Furthermore, by controlling the type and state of the metal added at this time, it is possible to adjust the color tone of the surface of the laminate and improve the added value of the glass substrate or the like on which the laminate is provided.

Embodiments Next, preferred embodiments of the present invention will be described based on the drawings.

In the present invention, on the heat source side surface of the visible light transmitting substrate,
A heat ray shielding laminate is formed by alternately laminating high refractive index thin film layers made of a visible light transparent material and low refractive index thin films made of a visible light transparent material.

In the examples, the visible light transmitting substrate is made of, for example, glass or plastic, and each high refractive index thin film layer coated on the heat source side surface of the substrate is made of TiO ₂ , CeO ₂ , ZnS, CdS
Or it is formed using ZrO ₂ . In addition, the low refractive index thin film layers, which are alternately laminated with the high refractive index thin film layers, are made of SiO ₂ with a film thickness that satisfies the infrared reflection condition.
It is formed using MgF ₂ , LiF, CeF ₃ or CaF ₂ .

The first characteristic feature of the present invention is that the outermost thin film layer of the multilayer films alternately laminated in this manner is a low refractive index thin film layer.

In the example, this low refractive index thin film layer on the outermost surface is made of SiO ₂ with a film thickness that satisfies the anti-reflection condition for visible light;
It is formed using MgF ₂ , LiF, CeF ₃ or CaF ₂ .

With the above configuration, the heat ray shielding laminate of the present invention can suppress the occurrence of color unevenness due to interference reflection of the multilayer film without substantially reducing the infrared reflectance.

Basic Configuration Example FIG. 1 shows a basic configuration example of the heat ray shielding laminate of the present invention. The heat ray shielding laminate in this example is
On the heat source side surface of the substrate 10 made of Corning No. 7059 glass with a thickness of 0.8 mm and a refractive index of about 1.5 and transparent in the visible and near-infrared regions, high refractive index thin film layers 20, 22, made of _TiO2 , 24 and low refractive index thin film layers 30 and 32 made of SiO ₂ are alternately laminated and coated, and a low refractive index thin film layer 40 made of SiO ₂ is further laminated and coated on the outermost surface as an interference anti-reflection layer.
It is formed into a multilayer film structure.

Here, each thin film layer 20, 22, 24, 3
The film thicknesses of 0, 32, and 40 were estimated by computer simulation, taking into account the previously measured refractive index of the TiO ₂ film or SiO ₂ film and the center wavelength (λ = 1000 nm) of the infrared rays to be interfered and reflected. The TiO ₂ thin film layers 20, 22, 24 are set to a range of 103±5 nm, and the SiO ₂ thin film layers 30, 32 are similarly set to a range of 103±5 nm.
is 172±8nm, and the outermost SiO ₂ thin film layer 40 is 86±5nm.
The range is set to m.

In manufacturing the heat ray shielding laminate of this example, the substrate 10 is thoroughly cleaned by RF sputtering.
Thereafter, a high refractive index thin film layer 20,
22, 24 and low refractive index thin film layers 30, 32, 40
are formed by alternately and sequentially laminating them.

Here, the high refractive index thin film layer 20, i.e.
The TiO ₂ thin film layer is formed by RF sputtering using a TiO ₂ target in an argon atmosphere containing 5 percent oxygen and a total pressure of 2×10 ⁻² TORR without any special substrate heating.

Furthermore, after the formation of the high refractive index thin film layer 20, the low refractive index thin film layer 30, that is, the SiO ₂ thin film layer, is formed using SiO ₂ under the same conditions as the TiO ₂ film forming conditions without breaking the vacuum. created using a target.

By repeating this film forming procedure, the film is formed on the substrate 10.
High refractive index thin film layers 20, 22, 24 made of TiO ₂
and low refractive index thin film layers 30, 32, made of SiO ₂ ,
40 is sequentially laminated and coated to form a six-layer TiO ₂ /SiO ₂ film.

FIG. 2 shows the spectral characteristics, that is, the transmittance characteristics with respect to wavelength, of the heat ray shielding laminate of this example formed in this manner.

Comparative Example Next, the characteristics of the heat ray shielding laminate of the present invention will be explained in comparison with the characteristics of a conventional heat ray shielding laminate.

FIG. 3 shows a conventional heat ray shielding laminate, and this heat ray shielding laminate is attached to the heat source side surface of the same glass substrate 10 as in the embodiment shown in FIG. Same high refractive index thin film layer 20, 2
2 and 24 and low refractive index thin film layers 30 and 32 are alternately laminated and coated in five layers. Therefore, this conventional heat ray shielding laminate is formed with a high refractive index thin film layer 24 laminated and coated on its outermost surface.

Here, the thickness and manufacturing method of each thin film layer 20, 22, 24 and 30, 32 are the same as in the embodiment of the present invention shown in FIG. 1 above.

FIG. 4 shows the spectral characteristics of the comparative example shown in FIG. 3, that is, the transmittance characteristics with respect to wavelength.

From the spectral characteristics of the comparative example shown in Figure 4, the conventional heat ray shielding laminate has good heat ray reflection properties with an average transmittance of about 81% in the visible range from 380 to 780 nm and an infrared reflectance of about 86% at 1000 nm. It is understood that

However, as shown in FIG. 4, this heat ray shielding laminate exhibits variations in transmittance within the visible range.
Here, high refractive index thin film layers 20, 22, 24
TiO ₂ thin film and low refractive index thin film layer 30 forming
Since the SiO ₂ thin film forming 32 itself does not have any absorption characteristics for visible light, the minimum transmittance shown in FIG. 4 means the maximum reflectance.

In this way, conventional heat ray shielding laminates reflect light of specific wavelengths in the visible range, causing color unevenness on the multilayer film surface. When a film is formed and used on commercial glass, the occurrence of color unevenness causes light pollution to the surrounding environment due to reflected light, and sometimes the color of the glass surface becomes unpleasant, reducing the added value of the film. was causing

On the other hand, the heat ray shielding laminate of the basic configuration example is
As is clear from the spectral characteristics shown in Figure 2,
Since it exhibits a substantially flat transmittance in the visible range of 380 to 780 nm, the occurrence of color unevenness is sufficiently suppressed. The visible light transmittance also shows an average of 91% or more, and the infrared reflectance maintains 83% at 1000 nm.

As described above, in the heat ray shielding laminate of the present invention, by making the outermost thin film layer the low refractive index thin film layer 40, the visible light transmittance is improved without substantially reducing the infrared reflectance, and the color It is understood that since the occurrence of unevenness can be effectively suppressed, it can be widely applied to, for example, automobiles, building window glass, and other uses.

Example Next, embodiments of the present invention will be described based on the drawings.

In this basic configuration example, high refractive index thin film layers and low refractive index thin film layers made of a visible light transparent material are alternately laminated on the heat source side surface of a visible light transparent substrate, as in the above embodiment, and The thin film layer is a low refractive index thin film layer.

A feature of the present invention is that a predetermined metal is added to the low refractive index thin film layer of the thin film layer formed in this manner.

In this way, by adding a different metal element to a low refractive index thin film layer, the visible light transmittance of the heat ray shielding laminate can be adjusted to an arbitrary value by adjusting the amount of the metal added or the deposition conditions of the thin film layer to which the metal is added. It is possible to set it to a value.

In particular, since a metal element is added to the low refractive index thin film layer, the degree of freedom in setting the visible light absorption wavelength is increased by adding the metal element, and the color tone of transmitted light can be set to an arbitrary value.

Here, the metal added to the low refractive index thin film layer is preferably a metal element such as Ag, Pd, Au, Co, Fe, or Cu, and in the examples, the amount of such metal element added is 1. The visible light transmittance is set to an arbitrary value by adjusting in the range of ~10A%.

FIG. 5 shows such a specific embodiment of the present invention, and the heat ray shielding laminate of the embodiment has a high refractive index made of a visible light transmitting material on the heat source side surface of the glass substrate 10. Six thin film layers 20, 22, 24 and low refractive index thin film layers 30, 32, 40 are alternately laminated, and the outermost thin film layer 40 is the low refractive index thin film layer as in the previous embodiment.

Here, the substrate 10 and each thin film 20, 2
The configurations, materials, etc. of 2, 24 and 30, 32, 40 are basically the same as those of the embodiment shown in FIG.
Consisting of TiO ₂ thin film layer, low refractive index thin film layer 30,3
2 and 40 are SiO ₂ thin film layers.

A feature of this embodiment is that 1 at percent metal Ag is added to the low refractive index thin film layers 30, 32, and 40 made of _SiO2 .

In manufacturing the heat ray shielding laminate of the example, a total pressure of 2× containing 5% oxygen was deposited on the substrate 10 by RF sputtering using a TiO ₂ target.
A high refractive index thin film layer 20 made of TiO ₂ is formed in a film thickness range of 103±5 nm in an argon atmosphere of 10 ^-2 TORR.

Following this, without breaking the vacuum, metal pieces of Ag were uniformly placed on the SiO ₂ target at an area ratio of 1:0.0017, and RF sputtering was performed in an argon atmosphere containing 5% oxygen to remove the Ag. Approximately 1at
A low refractive index thin film layer containing percent i.e.
A SiO ₂ thin film layer 30 is formed to a thickness of about 172±8 nm.

By repeating this film forming operation, the high refractive index thin film layers 20, 22, 24 and the metal element are formed on the surface of the substrate 10.
Low refractive index thin film layers 30, 32, and 40 containing Ag are alternately laminated and coated.

Note that the low refractive index thin film layer 40 on the outermost surface is formed to have a thickness within the range of 86±5 nm as in the above embodiment.

FIG. 6 shows the spectral characteristics, that is, the transmittance characteristics with respect to wavelength, of the heat ray shielding laminate of this example formed in this manner.

As is clear from the figure, the heat ray shielding laminate obtained in this example does not impair the infrared reflectance at about 1000 nm, and the wavelength range is 380 nm to 380 nm.
The transmittance in the visible range of 780 nm is almost flat, and color unevenness caused by transmittance fluctuations can be effectively suppressed.

In addition to this, in the heat ray shielding laminate of this example,
It is understood that the average transmittance in the visible range is suppressed by up to 77%.

That is, in the heat ray shielding laminate in which 1 at percent metal is added to the low refractive index thin film layers 30, 32, and 40 as in this example, the visible light is lower than that in the laminate of the basic configuration example described above in which no metal is added. It is understood that the transmittance has decreased by about 14% or more, and the shielding rate for thermal energy contained in the visible range has improved by more than 14%.

Note that this decrease in visible light transmittance is mainly due to the low refractive index thin film layers 30, 32, 40 containing metal Ag.
This is caused by the absorption of Therefore, it is conceivable that this heat absorption causes an increase in the surface temperature of each of these thin film layers 30, 32, 40, that is, the glass substrate 10, and slightly reduces the heat ray reflection characteristics. This does not pose any practical problem and can be ignored.

Thus, according to the present invention, the low refractive index thin film layer 3
It is possible to set the visible light transmittance to an arbitrary value by controlling the amount of metal added when forming SiO ₂ , 32, and 40 films and the gas composition during film formation. By increasing the amount of Ag added to 430nm from 1at% to 10at%, the visible light transmittance can be increased to 75nm.
Can be controlled in the range of ~30%.

Therefore, the visible light transmittance of the heat ray shielding laminate of the present invention can be set to any value depending on the purpose and use of the glass substrate covered with the laminate, and its application is extremely wide. I can say that there is.

For example, there is no legal standard for the visible light transmittance of automobile moonroofs and architectural window glass; in fact, it may be desirable for the visible light transmittance to be 50% or less for the purpose of protecting the secrets of the interior of a vehicle or residence. be. In such a case, by using the heat ray shielding laminate according to the present invention, it is possible to obtain a heat ray shielding glass whose visible light transmittance is set to a desired value.

In addition, the heat ray shielding glass obtained in this way has excellent infrared shielding properties as mentioned above, and can also shield heat rays in the visible range at any rate, reducing the heat load for cooling inside vehicles and residences. It becomes possible to exhibit excellent effects.

Further, as in this embodiment, the low refractive index thin film layer 30,
It was confirmed through experiments that the heat ray shielding laminate in which metal Ag was added to Nos. 32 and 40 exhibited a beautiful bronze color as a whole.

This coloring mechanism is based on the low refractive index thin film layers 30, 32, 4.
0, that is, it is presumed to be due to the absorption effect of Ag particles dispersed in the SiO ₂ thin film, and the color tone obtained in this way is very similar to that of bronze glass for automobiles, and has a deep and dignified appearance. The utility value is considered to be very high.

In other words, the number of cars equipped with bronze-colored glass has been rapidly increasing in the past few years, and they are becoming a symbol of luxury cars. On the other hand, in reality, bronze glass, which is colored by adding minute amounts of Se, Cd, etc. to the glass material, is very expensive because it is difficult to unify the color tone and the yield of additives is unstable. It has become a thing.

However, as mentioned above, the heat ray shielding laminate of this example has almost the same color tone as conventional bronze glass for automobiles, and also has a visible light transmittance of 75, which is the minimum standard required for automobile window glass for safe driving. well above the percentage. Therefore, by simply laminating and coating the glass surface with the heat ray shielding laminate of this example, it is possible to obtain automotive glass that has a classy feel that is completely comparable to the bronze automotive glass mentioned above. .

Furthermore, in the present invention, by controlling the amount of metal added to the low refractive index thin film layer, in the example, Ag, it is possible to make the color tone uniform with good reproducibility, and by simply applying the thin film to the glass surface. Since these color tones can be obtained by laminated coating, when the heat ray shielding laminate of the present invention is applied to bronze glass for automobiles, the cost is significantly lower than when manufacturing conventional bronze glass for automobiles. It becomes possible to aim down.

In addition, in this example, the low refractive index thin film layer 3
0,32,40, that is, when the metal Ag added to the SiO ₂ thin film is observed with a microscope, the metal
It has been confirmed that Ag is dispersed as particles with a size of about 1 nm and the amount thereof is small. Therefore, adding metallic Ag to the SiO ₂ thin film in this way _does not
It is understood that it does not affect the corrosion resistance, abrasion resistance, and heat resistance of the thin film at all, and there is no problem in practical use.

However, when the heat ray shielding laminate of this embodiment is used in a particularly harsh environment, as mentioned above, metal Ag is not uniformly dispersed in all of the SiO ₂ thin films 30, 32, and 40, and the glass Close to board 10
It is preferable to add metal Ag only to the SiO ₂ thin film. For example, a SiO ₂ thin film 3 near the glass substrate 10
If 3at% Ag is added only in 0, approx.
170nm _SiO2 thin film containing 1at% Ag
Transmittance equivalent to that of a 430 nm SiO ₂ thin film can be obtained.

Therefore, if the heat ray shielding laminate is expected to be used in a harsh environment, the glass substrate 1
By creating a structure in which metallic Ag is added to the SiO ₂ thin film layer that is closer to 0, the SiO ₂ thin film layer containing Ag is prevented from coming into direct contact with the outside air, and it is possible to effectively prevent the deterioration of its characteristics. Become.

Further, in the above embodiments, the heat ray shielding laminate was formed using the RF sputtering method, but the present invention is not limited to this, and the present invention is not limited to this.
It is also possible to form by a chemical method such as a dipping method or a spray method.

Further, as the substrate 10 used in the present invention, it is also possible to use a transparent resin substrate such as acrylic or polycarbonate, in addition to the glass substrate as in the above embodiment.

Furthermore, in this example, as the material of each thin film, TiO ₂ was used for the high refractive index thin film layer and SiO ₂ was used for the low refractive index thin film layer, but the present invention is not limited to this. Besides _TiO2 as
CeO ₂ , ZnS, CdS or ZrO ₂ is used, and in addition to SiO ₂ , CaF ₂ , LiF, MgF ₂ or CeF ₃ is used as a low refractive index thin film layer, and these are appropriately combined to achieve a film thickness that satisfies the interference conditions. It is possible to perform a multilayer coating and obtain optical properties similar to those of the previous example.

Further, in each of the above examples, a heat ray shielding laminate is formed by laminating six high refractive index thin film layers and low refractive index thin film layers alternately, but the present invention is not limited to this. It is possible to have an arbitrary number of layers depending on the purpose.

In addition, in each of the above-mentioned examples, a very wide range of studies were carried out regarding the types and amounts of elements added to the SiO ₂ thin film, the addition method such as RF sputtering conditions, the relationship between the film thickness, visible light transmittance, and color tone, etc. The explanation was based on experimental data. From the above explanation, it was confirmed that in the heat ray shielding laminate of the present invention, the visible light transmittance can be set to an arbitrary value by adjusting the amount of metal added. However, in addition to this, it has been confirmed that the color tone of the film is significantly influenced by the film forming conditions, the amount of metal added, the state of its dispersion, and the state of chemical bonding. For example, in addition to Ag, metal elements to be dispersed include Au, Cu, Pd,
By dispersing and adding Co, Fe, etc. in the state of the metal itself in the range of 1 to 10 at% into the constituent materials of the thin film layer, bronze color, yellow, reddish brown, blue color,
You can freely obtain any color tone.

Effects of the Invention As explained above, according to the present invention, a predetermined metal is dispersedly added to the low refractive index thin film layer forming the multilayer film, so that the visible light is It becomes possible to set the transmittance to an arbitrary value and obtain an effective heat-ray shielding effect.

Further, according to the present invention, by adding metal to the low refractive index thin film layer, it is possible to obtain a desired deep color tone as a whole of the multilayer film, thereby enhancing the aesthetic appearance of the glass substrate on which the heat ray shielding laminate is provided. It becomes possible to improve the added value. In particular, by adding metal to the low refractive index thin film layer, any color tone can be obtained depending on the amount of metal added and the particle size.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the basic configuration of the heat ray shielding laminate of the present invention, FIG. 2 is a spectral characteristic diagram of the heat ray shielding laminate shown in FIG. 1, and FIG. 3 is a structural explanatory diagram of a comparative example. Figure 4 is a spectral characteristic diagram of the comparative example shown in Figure 3;
FIG. 5 is an explanatory diagram showing an embodiment of the heat ray shielding laminate of the present invention, and FIG. 6 is a spectral characteristic diagram of the heat ray shielding laminate shown in FIG. 10...Substrate, 20...High refractive index thin film layer, 22
...High refractive index thin film layer, 24... High refractive index thin film layer,
30...Low refractive index thin film layer, 32...Low refractive index thin film layer, 40...Low refractive index thin film layer.

Claims (1)

[Claims] 1. High refractive index thin film layers and low refractive index thin film layers made of a visible light transparent material are alternately laminated on the heat source side surface of a visible light transparent substrate, and the outermost thin film layer has a low refractive index. 1. A heat ray shielding laminate characterized in that the visible light transmittance is set to an arbitrary value by adding a predetermined metal to the low refractive index thin film layer. 2. In the heat ray shielding laminate according to claim 1, the low refractive index thin film layer contains Ag, Pd, Au, Co, Fe.
Or add Cu metal and adjust the amount of the metal to 1~
Visible light transmittance adjusted in the range of 10at% to 90%
A heat ray shielding laminate characterized in that it can be set to any value in the range of ~30%. 3. In the heat ray shielding laminate according to claim 1 or 2, the visible light transmitting substrate is formed using glass or plastic, and the high refractive index thin film layer has a film thickness that satisfies the infrared reflection condition. _TiO2 ,
Formed using CeO ₂ , ZnS, CdS or ZrO ₂ ,
The low refractive index thin film layer is made of SiO ₂ , MgF ₂ , LiF, CeF ₃ or CaF ₂ , with only the outermost thin film layer having a thickness that satisfies the visible light anti-reflection condition, and the other film thicknesses satisfying the infrared reflection condition.
A heat ray shielding laminate characterized in that it is formed using.