JP7748816B2 - Double-glazed panel - Google Patents

Description

The present invention relates to a double-glazing panel.

A type of window glass known as a multi-glazing panel has a first glass pane and a second glass pane, with a Low-E film (low-emissivity film) that reflects infrared rays formed on one of the surfaces of the first glass pane and the second glass pane (see, for example, Patent Document 1). Using such a multi-glazing panel can improve the thermal insulation properties of the window glass.

Japanese Patent Application Laid-Open No. 2006-143525

However, double-glazed glass panels coated with Low-E (low-emissivity) coating have low radio wave permeability, making it difficult to transmit and receive radio waves, for example, from mobile phones.

In light of the above situation, there is a demand for double-glazed glass panels that have sufficient thermal insulation while ensuring radio wave transparency.

A characteristic configuration of a double-glazed glass panel according to the present invention is one comprising: a first glass plate; a second glass plate disposed opposite the first glass plate; and a spacer disposed between the first glass plate and the second glass plate to form an air gap between the first glass plate and the second glass plate; a plate surface of at least one of the first glass plate or the second glass plate has a coated region where a Low-E film is formed and an exposed region where the Low-E film is not formed, the exposed region being rectangular, and the distance between the outer edge of the exposed region and the outer edge of the plate surface having the Low-E film being 15 cm or less; an antenna being provided at a position overlapping with a corresponding region of either the first glass plate or the second glass plate that corresponds to the exposed region when viewed from a direction perpendicular to the first glass plate and the second glass plate; the exposed region being configured to allow radio waves corresponding to ultra-high frequencies (3 to 30 GHz, 100 mm to 10 mm) to pass through, and the distance from the lower end of the corresponding region to the lower end of the antenna being 10 mm or more .

According to this configuration, the double-glazing panel has a coated area on which a Low-E film is formed and an exposed area on which no Low-E film is formed on at least one of the surfaces of the first or second glass sheet. Therefore, the double-glazing panel can ensure thermal insulation through the coated area on which the Low-E film is formed. Furthermore, the double-glazing panel can ensure radio wave transparency through the exposed area on which no Low-E film is formed. This means that, for example, if an antenna is placed on the indoor side, it can transmit and receive radio waves to and from the outdoor side via the exposed area.

The exposed area can be formed by removing the Low-E film from the surface of the glass plate on which it is formed, or by using various masking materials. Therefore, the exposed area can be easily positioned at the desired location on the glass plate.

As another characteristic configuration, when the first glass sheet faces the exterior side and the sheet surface of the first glass sheet opposite the air gap layer is defined as the first surface, the sheet surface of the first glass sheet facing the air gap layer is defined as the second surface, the sheet surface of the second glass sheet facing the air gap layer is defined as the third surface, and the sheet surface of the second glass sheet opposite the air gap layer is defined as the fourth surface, it is preferable that the coated region and the exposed region are located on the second surface of the first glass sheet or the third surface of the second glass sheet.

According to this configuration, the Low-E film is disposed on the side of the first or second glass sheet facing the air gap layer. This allows heat to be blocked in the coating area where the Low-E film is formed, with the air gap layer acting as a boundary. As a result, the thermal insulation performance of the double-glazed glass panel can be improved.

As another characteristic configuration, it is preferable that the Low-E film is disposed on the second surface of the first glass plate, and the heat-shielding film is disposed on the first surface of the first glass plate, the third surface of the second glass plate, or the fourth surface of the second glass plate.

With this configuration, a Low-E film is disposed on the second surface of the first glass sheet, and a heat-shielding film is disposed on the other surface of the first or second glass sheet. This allows the double-glazed panel to block infrared rays contained in sunlight using the heat-shielding film, thereby providing heat-shielding properties across the entire surface of the double-glazed panel. In other words, the heat-shielding film ensures heat-shielding properties even in exposed areas where the Low-E film is not formed.

As another characteristic configuration, it is preferable that the Low-E film is disposed on the third surface of the second glass plate, and the heat-shielding film is disposed on the second surface of the first glass plate.

Most Low-E films reflect and block infrared rays, while most heat-shielding films absorb and block infrared rays. Therefore, heat-shielding films easily transfer heat to adjacent glass panes. Therefore, if a heat-shielding film is placed on the third surface of the second glass pane, the second glass pane will be heated by the heat-shielding film, and the room will be more likely to warm up due to radiant heat, resulting in a decrease in thermal insulation performance. On the other hand, if a heat-shielding film is placed on the second surface of the first glass pane, as in this configuration, the second glass pane will be separated from the heat-shielding film and will therefore be less likely to heat up. This improves the thermal insulation performance of the double-glazed panel.
Furthermore, if an antenna is placed indoors, the Low-E film is placed on the third surface of the second glass plate, which brings the antenna closer, and a noise reduction effect can be obtained by coupling the antenna with the Low-E film, which is made of, for example, a conductive thin film, thereby improving the performance of the antenna placed indoors.

As another characteristic configuration, it is preferable that the heat-shielding film is a heat-absorbing film.

When the heat-shielding film is a heat-absorbing film, as in this configuration, the heat-shielding film can absorb infrared rays, improving the heat-shielding performance of the double-glazed glass panel.

Another characteristic feature is that the surface resistivity of the heat-shielding film is preferably 20 Ω or more.

When the surface resistivity of the heat-shielding film is 20 Ω or higher, as in this configuration, the heat-shielding film has high radio wave transmittance, reducing the loss of radio waves when passing through the heat-shielding film.

As another characteristic configuration, the plate surface having the Low-E film has at least one exposed area, and it is preferable that the exposed area be larger than a 10 cm square area and smaller than a 60 cm square area.

When transmitting and receiving radio waves in the 5G band, the exposed area on the surface of the double-glazed glass panel that has the Low-E film is preferably 10 cm square or larger. A larger exposed area is preferable for more reliable transmission and reception of radio waves in the 5G band. However, if the area of the exposed area is increased, the proportion of the exposed area on the first or second glass sheet increases, further reducing the insulating properties of the double-glazed glass panel. Therefore, in this configuration, the surface of the first or second glass sheet that has the Low-E film has at least one exposed area that is larger than a 10 cm square area and smaller than a 60 cm square area. This allows the double-glazed glass panel to minimize the impact of the exposed area on the insulating properties.

The exposed area on the plate surface having the Low-E film is preferably positioned to allow the passage of radio waves corresponding to high frequencies (30-300 MHz, 10 m-1 m), ultra-high frequencies (300-3000 MHz, 1 m-100 mm), and/or even higher ultra-high frequencies (3-30 GHz, 100 mm-10 mm).

The exposed area is also preferably positioned to allow the passage of electromagnetic radiation corresponding to ultra-high frequencies and/or ultra-high frequencies only, more preferably radio waves corresponding to mobile phones or mobile phones only, and/or devices that can connect wirelessly to the Internet.

As another characteristic configuration, it is preferable that the plate surface having the Low-E film has only one exposed area.

According to this configuration, the surface of the first or second glass sheet that has the Low-E film has one exposed area. This allows the double-glazed glass panel to further reduce the impact of the exposed area on its thermal insulation properties. Furthermore, having one exposed area makes it easier to position an antenna on the radio wave transmission path, making it easier to improve the antenna's reception sensitivity.

As another characteristic configuration, it is preferable that the difference in visible light transmittance between the coated area and the exposed area, calculated in accordance with JIS R3106 (1998), is less than 10%.

By setting the difference in visible light transmittance between the coated and exposed areas small, as in this configuration, the difference in appearance between the coated and exposed areas is reduced. This allows the double-glazed glass panel to have a smaller impact on the appearance of the exposed areas.

Another characteristic feature is that the difference in visible light transmittance between the coated region and the exposed region is preferably less than 5%.

With this configuration, the difference in visible light transmittance between the coated area and the exposed area is less than 5%. Therefore, the impact of the exposed area on the appearance of the double-glazed glass panel can be further reduced.

As another characteristic configuration, it is preferable that the difference in reflected color tone between the coated area and the exposed area, calculated in accordance with JIS Z8781-4 (2013) based on observation from outside the room, is within 10 for a* and within 10 for b* on the CIE L*a*b* chromaticity coordinate diagram.

By setting a small difference in the reflected color tone between the coated and exposed areas, as in this configuration, the difference in appearance between the coated and exposed areas is reduced. This allows the double-glazed glass panel to minimize the impact of the exposed areas on its appearance.

As another characteristic configuration, it is preferable that the difference in the reflected color tone between the coated area and the exposed area is within 5 for a* and within 5 for b* on the CIE L*a*b* chromaticity coordinate diagram.

With this configuration, the difference in reflected color tone between the coated area and the exposed area is within 5. Therefore, the impact of the exposed area on the appearance of the double-glazed glass panel can be further reduced.

As another characteristic feature, it is preferable that the Low-E film is a conductive thin film.

With this configuration, the Low-E film is a conductive thin film that can transmit and capture visible light while reflecting infrared light to block heat. This improves the thermal insulation performance of the double-glazed panel.

Another characteristic feature is that the surface resistivity of the conductive thin film is preferably less than 20 Ω.

With this configuration, the surface resistivity of the conductive thin film is less than 20 Ω and has high reflectivity in the wavelength range from the infrared to the radio wave range. As a result, the coated area has low radio wave transmittance, but also low emissivity. This improves the thermal insulation performance of the double-glazed glass panel.

As another characteristic feature, the Low-E film preferably contains a metal layer whose main component is silver.

When the Low-E film contains a metal layer primarily composed of silver, as in this configuration, the Low-E film can suppress heat radiation. This can improve the thermal insulation performance of the double-glazed glass panel.

Another characteristic feature is that the thickness of the metal layer is preferably 5 nm or more and 15 nm or less.

In this configuration, the Low-E film has a metal layer of a specified thickness, which allows the Low-E film to suppress heat radiation. This improves the insulating performance of the double-glazed glass panel. Furthermore, by keeping the metal layer thickness to 15 nm or less, the impact of the Low-E film on the appearance can be minimized.

In another configuration, the Low-E film has a first anti-reflection layer on the inner side of the metal layer, closer to the plate surface on which the Low-E film is formed, and it is preferable that the total optical film thickness of the first anti-reflection layer is 60 nm or more and 120 nm or less.

With this configuration, the Low-E film has a first anti-reflection layer of a specified thickness located closer to the glass plate surface than the metal layer. This allows the first anti-reflection layer to protect the metal layer, ensuring that the low-emission performance of the metal layer is fully realized. Furthermore, the multi-glazed panel can achieve high visible light transmittance and a favorable reflection color tone.

As another characteristic configuration, the Low-E film preferably has a second anti-reflection layer on the outer side of the metal layer, away from the plate surface on which the Low-E film is formed, and the total optical film thickness of the second anti-reflection layer is preferably 60 nm or more and 120 nm or less.

With this configuration, the Low-E film has a second anti-reflection layer of a specified thickness located on the far side of the glass plate from the metal layer. This allows the second anti-reflection layer to protect the metal layer, ensuring that the low-emission performance of the metal layer is fully realized. Furthermore, the multi-glazed panel can achieve high visible light transmittance and a favorable reflection color tone.

As another characteristic feature, it is preferable that the conductive thin film is a TCO (Transparent Electrically Conductive Glass) thin film.

A TCO-based thin film made of a transparent conductive oxide is a transparent conductive film that is coated on the surface of glass during the glass manufacturing process. Therefore, by using a TCO-based thin film as the conductive thin film, as in this configuration, the conductive thin film can be easily placed on the glass plate. Furthermore, because TCO-based thin films are transparent, the coated areas of a double-glazed panel can be made transparent. This reduces the impact of the coated areas on the appearance of the double-glazed panel.

As another characteristic configuration, it is preferable that the exposed area is an area where the antenna can be installed.

With this configuration, the antenna is installed in an exposed area where no conductive film is formed, allowing the antenna to transmit and receive radio waves effectively through the exposed area, which has high radio wave transparency.

1 is a cross-sectional view of a double-glazing panel according to a first embodiment. FIG. 2 is a view taken along the line II-II in FIG. FIG. 10 is a cross-sectional view of a double-glazing panel according to a second embodiment. FIG. 4 is a view taken along the line IV-IV in FIG. 3. FIG. 2 is a cross-sectional view of a double glazing panel showing the location of the antenna area. FIG. 2 is a cross-sectional view of a double glazing panel showing the location of the antenna area. FIG. 2 is a plan view showing the positional relationship between a corresponding region and an antenna region. FIG. 2 is a plan view showing the positional relationship between a corresponding region and an antenna region. FIG. 2 is a plan view showing the positional relationship between a corresponding region and an antenna region. 1A and 1B are diagrams showing the configuration and test results of an example. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing a simulation result of radio waves passing through an aperture. FIG. 10 is a diagram showing another embodiment of a double glazing panel.

First Embodiment
A first embodiment of a double-glazing panel (hereinafter also referred to as "glass panel") 100 according to the present invention will be described with reference to Figures 1 and 2. The glass panel 100 can be used for a variety of purposes, for example, as window glass for buildings, and for mobile objects such as automobiles, aircraft, ships, and trains. In addition, various antennas 60 for receiving radio waves can be disposed on the indoor (interior) side of both plate surfaces of the glass panel 100.

<Overview of double-glazed glass panels>
As shown in FIG. 1 , the glass panel 100 includes two glass sheets, namely, a first glass sheet 1 and a second glass sheet 2, each having a substantially identical rectangular outer surface. The glass sheets 1 and 2 are connected to each other by a spacer 5 disposed around their peripheries. The spacer 5 forms an air gap 3 between the two glass sheets 1 and 2. Furthermore, a Low-E film 41 having radio wave blocking properties is formed on the surface (second surface 12) of the first glass sheet 1 facing the air gap 3. The Low-E film 41 is, for example, a conductive thin film. The surface resistivity of the conductive thin film is preferably less than 20 Ω. In this case, the conductive thin film (Low-E film 41) has high reflectivity in the wavelength range from the infrared to the radio wave range. Therefore, the coating region 42 where the Low-E film 41 is formed has low radio wave transmittance but also low emissivity. This improves the thermal insulation performance of the double-glazed glass panel. The antenna 60 for transmitting and receiving radio waves may be installed on the indoor-facing surface (fourth surface 14) of the glass panel 100, or may be installed on the indoor ceiling, etc. Although not shown, the air gap layer 3 is sealed by a frame body on which a sealing material is arranged and which is located outside the spacer 5.

The first glass plate 1 has a first surface 11, which is the surface facing the exterior, and a second surface 12, which is the surface facing the air gap layer 3. The second glass plate 2 has a third surface 13, which is the surface facing the air gap layer 3, and a fourth surface 14, which is the surface facing the interior.

The second surface 12 of the first glass plate 1 has a coated region 42 where a Low-E film 41 is formed. As shown in FIG. 2, an exposed region 43 where the Low-E film 41 is not formed is provided on a portion of the second surface 12, which is the plate surface on which the Low-E film 41 is formed. The exposed region 43 is an area where an antenna 60 can be installed. As shown in FIG. 1, the antenna 60 is attached, for example, to the plate surface on the indoor (vehicle interior) side of the glass panel 100. By installing the antenna 60 in the exposed region 43 in this way, the antenna 60 can transmit and receive radio waves well via the exposed region 43.

<Low-E film>
The Low-E film 41 is not particularly limited as long as it does not impede the objectives of the present invention, but is preferably a multilayer film including a layer primarily composed of silver. The Low-E film 41 is also preferably a multilayer film formed by stacking two or more layers selected from a metal layer, a metal oxide layer, a metal nitride layer, and a metal oxynitride layer. A suitable example of the metal layer is a silver layer. A suitable example of the metal oxide layer is a tin oxide layer, a titanium oxide layer, or a zinc oxide layer. A suitable example of the metal nitride layer is silicon nitride. A suitable example of the metal oxynitride layer is silicon oxynitride. The Low-E film 41 is preferably formed by a vacuum deposition method such as physical vapor deposition (PVD), with sputtering being particularly preferred because it allows for uniform deposition over a large area. The exposed region 43 is formed, for example, by forming the Low-E film 41 on a glass plate by sputtering and then removing the Low-E film 41 by laser processing or the like. The exposed region 43 may also be formed using various masking materials. By forming the exposed area 43 in this manner, it can be easily positioned at a desired position on the glass plate.

More preferably, the Low-E film 41 is made of a multilayer structure consisting of three or more layers selected from a tin oxide layer, a silicon nitride layer, a silicon oxynitride layer, a titanium oxide layer, a zinc oxide layer, and a silver layer. Most preferably, the Low-E film 41 is made of three or five layers consisting of, in order from the glass plate surface, (1) a tin oxide layer (an example of a first antireflection layer), a zinc oxide layer (an example of a first antireflection layer), a silver layer (an example of a metal layer), an aluminum-added zinc oxide layer (an example of a second antireflection layer), and a tin oxide layer (an example of a second antireflection layer); and (2) a silicon nitride layer (an example of a first antireflection layer), an aluminum-added zinc oxide layer (an example of a first antireflection layer), a silver layer (an example of a metal layer), and an aluminum-added zinc oxide layer (an example of a second antireflection layer).

The Low-E film contains a metal layer whose main component is silver. The thickness of the metal layer is preferably 5 nm to 15 nm, and more preferably 5 nm to 10 nm. By having a metal layer of a predetermined thickness whose main component is silver, the Low-E film 41 can suppress heat radiation. This allows the glass panel 100 to have improved heat insulation performance. Furthermore, by having a metal layer whose thickness is 15 nm or less, the impact of the Low-E film on appearance can be reduced.

The Low-E film 41 preferably has a first anti-reflection layer on the inner side of the metal layer, closer to the plate surface on which the Low-E film 41 is formed, and the total optical thickness of the first anti-reflection layer is 60 nm or more and 120 nm or less. The Low-E film 41 preferably has a second anti-reflection layer on the outer side of the metal layer, farther from the plate surface on which the Low-E film 41 is formed, and the total optical thickness of the second anti-reflection layer is 60 nm or more and 120 nm or less. The optical thickness can be calculated by (refractive index n) x (film thickness d). If the first anti-reflection layer (second anti-reflection layer) is composed of multiple films, the sum of the optical thicknesses calculated for each film is the optical thickness of the first anti-reflection layer (second anti-reflection layer). When calculating the optical thickness, the refractive index varies depending on the wavelength of visible light. Here, the optical thickness is based on the refractive index when the wavelength of visible light is a common reference wavelength in the visible range (550 nm).

As described above, the Low-E film 41 has a first anti-reflection layer of a predetermined thickness located closer to the second surface 12 of the first glass plate 1 relative to the metal layer, which protects the metal layer and gives the Low-E film low reflection performance, ensuring heat insulation. It also enables the glass panel 100 to achieve high visible light transmittance and a favorable reflection color tone.

Furthermore, even if a second anti-reflection layer of a predetermined thickness is present on the side of the first glass plate 1 farther from the second surface 12 relative to the metal layer, the Low-E film 41 protects the metal layer, allowing the Low-E film to have low reflection performance and reliably block heat. It also enables the glass panel 100 to achieve high visible light transmittance and a favorable reflection color tone.

In this embodiment, the second surface 12 (plate surface) of the first glass plate 1, which has the coated region 42 and the exposed region 43, has only one exposed region 43. Having only one exposed region 43 makes it easier to position the antenna 60 on the transmission path of the radio waves, and the reception sensitivity of the antenna 60 can be easily improved.

The exposed area 43 is rectangular, and the distance between the outer edge 43a of the exposed area 43 and the outer edge 12a of the second surface 12 (plate surface) having the coated area 42 and exposed area 43 is within 15 cm. Furthermore, the exposed area 43 is larger than a 10 cm square area and smaller than a 60 cm square area.

By making the exposed area 43 rectangular, the radio wave transmittance of the glass panel 100 can be maximized when the antenna shape is rectangular. Furthermore, when transmitting and receiving radio waves in the 5G band, the exposed area 43 of the glass panel 100 is preferably 10 cm square or larger. A larger area of the exposed area 43 is preferable for more reliable transmission and reception of radio waves in the 5G band. However, if the area of the exposed area 43 is increased, the proportion of the exposed area 43 in the first glass plate 1 increases, further reducing the thermal insulation properties of the glass panel 100. Therefore, in this embodiment, the second surface 12 of the first glass plate 1 has at least one exposed area 43, which is larger than a 10 cm square area and smaller than a 60 cm square area. This allows the glass panel 100 to minimize the impact of the exposed area 43 on the thermal insulation properties.

Furthermore, if the distance between the outer edge 43a of the exposed region 43 and the outer edge 12a of the second surface 12 of the first glass plate 1 is within 15 cm, the outer edge 43a of the exposed region 43 will be close to the outer edge 12a of the second surface 12 of the first glass plate 1. This allows the exposed region 43 to be positioned close to the periphery of the second surface 12 of the first glass plate 1. As a result, the appearance of the glass panel 100 can be minimized due to the exposed region 43.

The difference in visible light transmittance between the coated region 42 and the exposed region 43, calculated in accordance with JIS R3106 (1998), is less than 10%. It is more preferable that the difference in visible light transmittance between the coated region 42 and the exposed region 43 be less than 5%.

The difference in the reflected color tone between the coated region 42 and the exposed region 43 and the plate surface not having the coated region 42 or the exposed region 43, calculated in accordance with JIS Z8781-4 (2013), is within 10 for a* and within 10 for b* on the CIE L*a*b* chromaticity coordinate diagram. It is more preferable that the difference in the reflected color tone between the coated region 42 and the exposed region 43 is within 5 for a* and within 5 for b* on the CIE L*a*b* chromaticity coordinate diagram.

The exposed area 43 is preferably positioned to allow the passage of radio waves corresponding to high frequencies (30-300 MHz, 10 m-1 m), ultra-high frequencies (300-3000 MHz, 1 m-100 mm), and/or even ultra-high frequencies (3-30 GHz, 100 mm-10 mm).

Furthermore, the exposed area 43 is preferably positioned to allow the passage of electromagnetic radiation corresponding to ultra-high frequencies and/or ultra-high frequencies only, more preferably radio waves corresponding to mobile phones or mobile phones only, and/or devices that can connect wirelessly to the Internet.

Second Embodiment
3 and 4 , in the glass panel 100 of the second embodiment, a heat-shielding film 51 is disposed on the second surface 12 of the first glass plate 1, and a Low-E film 41 is disposed on the third surface 13 of the second glass plate 2. The third surface 13 of the second glass plate 2 is provided with a coated region 42 where the Low-E film 41 is formed, and an exposed region 43 where the Low-E film 41 is not formed. The exposed region 43 is an area where an antenna 60 can be installed. As in the first embodiment, the Low-E film 41 is formed of, for example, a conductive thin film.

The exposed area 43 is rectangular, and the distance between the outer edge 43a of the exposed area 43 and the outer edge 13a of the third surface 13 (plate surface) of the second glass plate 2 having the coated area 42 and exposed area 43 is within 15 cm. The exposed area 43 is larger than a 10 cm square area and smaller than a 60 cm square area. Because 5G band radio waves are highly directional (straight-line), it is important to design the angle of radio wave transmission and reception according to the usage environment. In other words, the position of the exposed area 43 relative to the glass plate is important. Therefore, it is desirable to appropriately arrange the number, size, and position of the exposed areas 43 depending on the usage environment and the desired direction of radio wave transmission and reception.

<Heat-shielding film>
The heat-shielding film 51 is not particularly limited as long as it does not impede the object of the present invention, but is preferably a multilayer film including a layer whose main component is titanium nitride. A suitable example of a metal nitride layer is a titanium nitride layer. The film thickness of the heat-shielding film 51 is selected appropriately depending on the type of film to be laminated, but is typically 5 to 100 nm, and preferably 10 to 50 nm. The heat-shielding film 51 is composed of, for example, a heat-ray absorbing film. If the heat-shielding film 51 is a heat-ray absorbing film, infrared rays can be absorbed by the heat-shielding film 51, thereby improving the heat-shielding properties of the glass panel 100.

As shown in the table in Figure 8 below, the double-glazed glass panel having the heat-shielding film 51 (exposed area in Example 2) has a visible light transmittance of 60% or less and a solar heat gain coefficient calculated in accordance with JIS R3106 (1998) of 0.6 or less, while the Low-E film 41 (coated area in Example 1) has a visible light transmittance of 70% or more and a solar heat gain coefficient of 0.7 or more.

The Low-E film 41 is a heat ray reflective film containing a metal layer primarily composed of silver, for example. Heat ray reflective films have low radio wave transmittance and a surface resistivity of, for example, less than 20 Ω. On the other hand, the heat shielding film 51 is a heat ray absorbing film having, for example, a titanium nitride layer. Heat ray absorbing films have radio wave transmittance and a surface resistivity of 20 Ω or more. The surface resistivity of the TiN/TiO2 film used as the heat shielding film 51 in Example 2, described below, is 5000 Ω.

In the glass panel 100 of the second embodiment, the difference in visible light transmittance between the coated region 42 and the exposed region 43, calculated in accordance with JIS R3106 (1998), is also less than 10%. It is more preferable that the difference in visible light transmittance between the coated region 42 and the exposed region 43 be less than 5%.

Furthermore, the difference in reflected color tone between the coated region 42 and the exposed region 43, calculated by observation from the outside of the room in accordance with JIS Z8781-4 (2013), is within 10 for a* and within 10 for b* on the CIE L*a*b* chromaticity coordinate diagram. It is more preferable that the difference in reflected color tone between the coated region 42 and the exposed region 43 is within 5 for a* and within 5 for b* on the CIE L*a*b* chromaticity coordinate diagram.

In the first and second embodiments, the antenna can be placed, for example, on the surface facing the interior, i.e., the fourth surface 14 of the second glass plate 2. In this case, the position of the antenna area where the antenna is placed is not particularly limited, but it can be placed, for example, as shown in FIG. 5, particularly for 5G radio waves. In the example of FIG. 5, when both glass plates 1 and 2 are viewed from a direction perpendicular to them, the antenna 60 can be set in an area 6 (hereinafter referred to as the "corresponding area 6") on the fourth surface 14 of the second glass plate 2 that corresponds to the exposed area 43. The antenna 60 may be the same size as the corresponding area 6, or it may be smaller than the corresponding area 6. For example, because 5G radio waves have a high degree of directionality, placing the antenna 60 in the corresponding area 6 as described above can particularly increase the sensitivity of transmitting and receiving 5G radio waves.

Alternatively, as shown in Figures 6 and 7A, the antenna 60 can be formed so that at least a portion thereof extends into the corresponding area 6. In the example of Figures 6 and 7A, the lower end of the antenna 60 is located a distance L inward from the lower end of the corresponding area 6. This takes into account the linearity of 5G radio waves and assumes, for example, that the radio waves are incident at an angle on the glass body. That is, as shown in Figure 6, when highly linear radio waves are incident, the strength of the radio waves reaching the area extending from the edge of the corresponding area 6 to the distance L becomes weak. This distance L is, for example, preferably 10 mm or more, more preferably 20 mm or more, and particularly preferably 50 mm or more. Furthermore, the length S of the end portion extending into the corresponding area by this distance L (see Figure 7A) can be, for example, 10 mm or more.

A portion of the antenna 60 may extend beyond the corresponding region 6, as shown in FIG. 7B, for example. Also, as shown in FIG. 7C, the end of the antenna 60 that is a distance L away from the corresponding region 6 may be a side edge of the antenna 60.

The glass panels of Examples 1 and 2 are described below. The configuration of the glass panels of Examples 1 and 2 is as shown in Figure 8.

Example 1
The glass panel of Example 1 corresponds to the glass panel 100 of the first embodiment, and has a Low-E film 41 formed on the second surface 12 of the first glass plate 1. As shown in the table of Fig. 8 , the Low-E film 41 is formed by laminating tin oxide, zinc oxide, silver, a zinc-aluminum alloy, zinc oxide, and tin oxide from the plate surface of the second surface 12. The first glass plate 1 and the second glass plate 2 are made of float glass (soda-lime glass) with a plate thickness of 6 mm, and the gap layer 3 between the first glass plate 1 and the second glass plate 2 is 12 mm.

The Low-E film 41 has a first antireflection layer made of tin oxide (19 nm thick) and zinc oxide (27 nm thick) on the side closer to the plate surface on which the Low-E film 41 is formed, which is inside the silver metal layer. The Low-E film 41 has silver (6.5 nm thick) as the metal layer. The Low-E film 41 has a second antireflection layer made of a zinc-aluminum alloy (0.4 nm thick), zinc oxide (27 nm thick), and tin oxide (15 nm thick) on the side farther from the plate surface on which the Low-E film 41 is formed.
The total optical thickness of the first antireflection layer (inner antireflection layer optical thickness) is approximately 94 nm. The total optical thickness of the second antireflection layer (outer antireflection layer optical thickness) is approximately 85 nm. When calculating the optical thickness, the refractive index varies depending on the wavelength of visible light. Here, the optical thickness is based on the refractive index when the wavelength of visible light is a common reference wavelength in the visible range (550 nm). Incidentally, the refractive index of tin oxide is 2.08, and the refractive index of zinc oxide is 2.00.

Example 2
The glass panel of Example 2 corresponds to the glass panel 100 of the second embodiment, and has a heat-shielding film 51 formed on the second surface 12 of the first glass plate 1, and a Low-E film 41 formed on the third surface 13 of the second glass plate 2. As shown in the table of Fig. 8 , the Low-E film 41 has the same layer structure as in Example 1, and the heat-shielding film 51 is formed by laminating titanium nitride (film thickness 6 nm) and titanium oxide (film thickness 5 nm) from the plate surface of the second surface 12 of the first glass plate 1.

[First Test]
The visible light transmittance and visible light reflectance were calculated in accordance with JIS R3106: 1998 for the coated region 42 and exposed region 43 of the double-glazing panels of Examples 1 and 2. The values of the visible light transmittance and visible light reflectance, the solar heat gain coefficient calculated in accordance with JIS R3106 (1998), and the overall unit transmittance (U value) calculated in accordance with JIS R3107 (1998) are shown in Figure 8.

[First test results]
In Example 1, the difference in "visible light transmittance" between the coated region 42 and the exposed region 43 was 1.8%, the difference in "visible light reflectance/out" (outdoor side) was 2.4%, and the difference in "visible light reflectance/in" (indoor side) was 1.8%. Thus, in Example 1, the differences in visible light transmittance and visible light reflectance between the coated region 42 and the exposed region 43 were all within 5%. This proves that there is little difference in appearance between the coated region 42 and the exposed region 43 in the glass panel of Example 1.

In Example 2, the difference in "visible light transmittance" between the coated region 42 and exposed region 43 was 1.4%, the difference in "visible light reflectance/out" (outside the room) was 0.9%, and the difference in "visible light reflectance/in" (inside the room) was 2.5%. Thus, in Example 2 as well, the differences in visible light transmittance and visible light reflectance between the coated region 42 and exposed region 43 were all within 5%. This demonstrated that there was little difference in appearance between the coated region 42 and exposed region 43 in the glass panel of Example 2 as well. Furthermore, the solar heat gain coefficient was lower compared to Example 1, demonstrating that the formation of the heat-shielding film 51 improves the heat-shielding properties of the double-glazed glass panel.

[Second Test]
In the coated region 42 and exposed region 43 of the double-glazing panels of Examples 1 and 2, the transmitted color tone and reflected color tone were calculated based on observation from the outside of the room in accordance with JIS Z8781-4 (2013). Specifically, the transmitted color tone and reflected color tone were calculated as a* and b* in the CIE L*a*b* chromaticity coordinate diagram. The values of the transmitted color tone and reflected color tone are shown in Figure 8.

[Second test results]
The coated region 42, on which the Low-E film 41 is formed, has different transmitted color tones and reflected color tones from the exposed region 43, on which the Low-E film 41 is not formed. In Example 1, the difference in "transmitted color tone" between the coated region 42 and the exposed region 43 was 1.0 for "a*" and 1.7 for "b*." The difference in "reflected color tone/out" (outside of the room) was 1.0 for "a*" and 1.0 for "b*." The difference in "reflected color tone/in" (inside of the room) was 0.2 for "a*" and 0.1 for "b*." Thus, in Example 1, the difference in "a*" and the difference in "b*" between the coated region 42 and the exposed region 43 in "transmitted color tone,""reflected color tone/out" (outside of the room), and "reflected color tone/in" (inside) were all within 5. This demonstrates that there is little difference in appearance between the coated region 42 and the exposed region 43 in the glass panel of Example 1.

In Example 2, the difference in "transmitted color tone" between the coated region 42 and exposed region 43 was 0.9 for "a*" and 0.1 for "b*," the difference in "reflected color tone/out" (outside) was 0.1 for "a*," and 0.6 for "b*," and the difference in "reflected color tone/in" (inside) was 1.2 for "a*" and 0.9 for "b*." Thus, in Example 2, the difference in "a*" and the difference in "b*" between the coated region 42 and exposed region 43 in "transmitted color tone," "reflected color tone/out" (outside) and "reflected color tone/in" (inside) are all within 5. This proves that there is little difference in appearance between the coated region 42 and exposed region 43 in the glass panel of Example 2 as well.

(Consideration of antenna area location)
A simulation was performed using a shielding plate having an opening of 100 mm x 100 mm through which radio waves can pass. This opening was assumed to be the exposed area 43. A simulation was performed in which 30 GHz and 10 GHz radio waves were irradiated onto this shielding plate. The irradiation angles of the radio waves with respect to the shielding plate were 90°, 60°, and 30°. This simulation was performed using the electromagnetic field simulator Micro-Stripes2. FIG. 9A is a diagram showing the distribution of radio waves when 30 GHz radio waves are irradiated at 90°, and FIG. 9B is a diagram showing the distribution of radio waves when 10 GHz radio waves are irradiated at 90°. FIG. 10A is a diagram showing the distribution of radio waves when 30 GHz radio waves are irradiated at 60°, and FIG. 10B is a diagram showing the distribution of radio waves when 10 GHz radio waves are irradiated at 60°. FIG. 11A is a diagram showing the distribution of radio waves when 30 GHz radio waves are irradiated at 30°, and FIG. 11B is a diagram showing the distribution of radio waves when 10 GHz radio waves are irradiated at 30°. In these figures, radio waves are emitted in the direction of the arrows, and the areas surrounded by dotted lines indicate the distribution of strong or weak radio waves.

9 to 11, it can be seen that the radio waves travel straight in the direction of the arrow after passing through the opening.
In particular, it can be seen that the high-frequency 30 GHz radio waves have a higher degree of directivity than the low-frequency 10 GHz radio waves. It can be seen that the low-frequency 10 GHz radio waves spread out somewhat after passing through the opening.

In addition, because 30 GHz radio waves have a high tendency to travel in a straight line, when the radio waves are irradiated at an angle, as shown in Figures 10A and 11A, for example, not much of the radio waves reach the triangular area M after passing through the opening.

From the above, it has been found that, particularly for 5G radio waves, it is preferable to locate the antenna region in a position corresponding to the exposed region 43, as shown in Figures 5 to 7. Furthermore, when radio waves are incident at an angle, an area with weak radio wave strength such as the above-mentioned region M will occur. Therefore, it is preferable to locate the antenna region at a distance L from the corresponding region 6 depending on the direction of the radio waves, as shown in Figures 6 and 7, for example.

Figure 10A shows that one side of region M is 24 mm. This assumes, as an example, a glass body with a total thickness of 24 mm (first glass plate: 9 mm, air gap: 6 mm, second glass plate: 9 mm). In this case, it is shown that the radio wave strength is weak in a region on the fourth surface 14 of the second glass plate 2, extending 13.9 mm from the edge of the corresponding region. On the other hand, Figure 11A shows that one side of region M is 30 mm. This assumes, as an example, a glass body with a total thickness of 30 mm (first glass plate: 9 mm, air gap: 12 mm, second glass plate: 9 mm). In this case, it is shown that the radio wave strength is weak in a region on the fourth surface 14 of the second glass plate 2, extending 52 mm from the edge of the corresponding region.

Based on the above and the results of Figures 10A and 11A, the distance L shown in Figures 6 and 7 is preferably 10 mm or more, more preferably 20 mm or more, and particularly preferably 50 mm or more.

(Consideration of the size of the antenna area)
Simulations were performed in the same manner as described above (Study of the Antenna Region Position). Simulations were performed with aperture sizes of 100 mm x 100 mm and 33 mm x 33 mm. The results are shown in FIG. 12. FIG. 12A shows the results of a simulation using a 100 mm x 100 mm aperture (frequency: 30 GHz), and FIG. 12B shows the results of a simulation using a 33 mm x 33 mm aperture (frequency: 10 GHz). As shown in these figures, if the aperture size is small, the radio waves that pass through the aperture will spread and will not be able to propagate in a straight line. Therefore, it was found that the size of the above-mentioned exposed region 43 is preferably larger than a 33 mm x 33 mm rectangle.

Other Embodiments
(1) In the above embodiment, an example was shown in which the Low-E film 41 was disposed on the second surface 12 of the first glass plate 1 or the third surface 13 of the second glass plate 2. However, the Low-E film 41 may also be disposed on the first surface 11 of the first glass plate 1 or the fourth surface 14 of the second glass plate 2. In other words, the Low-E film 41 may be disposed on any one or two or more of the surfaces 11, 12 of the first glass plate 1 and the surfaces 13, 14 of the second glass plate 2.

(2) In the second embodiment, the heat-shielding film 51 is disposed on the second surface 12 of the first glass plate 1, and the Low-E film 41 is disposed on the third surface 13 of the second glass plate 2. However, the heat-shielding film 51 may be disposed on the first surface 11 of the first glass plate 1, and the Low-E film 41 may be disposed on the third surface 13 of the second glass plate 2. Alternatively, the Low-E film 41 may be disposed on the second surface 12 of the first glass plate 1, and the heat-shielding film 51 may be disposed on the first surface 11 of the first glass plate 1 or the third surface 13 or fourth surface 14 of the second glass plate 2. If the heat-shielding film 51 is disposed on the first surface 11 of the first glass plate 1, the glass panel 100 can be provided with heat-shielding properties over the entire surface of the glass panel 100, since the heat-shielding film 51 blocks infrared rays contained in sunlight. In other words, the heat-shielding film 51 ensures heat-shielding properties even in exposed areas where the Low-E film 41 is not formed.

(3) In the above embodiment, an example was shown in which the Low-E film 41 was a film containing a metal layer primarily composed of silver. However, the Low-E film 41 may also be a TCO-based thin film. A TCO-based thin film is a transparent conductive film that is coated on the glass surface during, for example, the glass manufacturing process (online CVD manufacturing method). The metal thin film of this transparent conductive film is a fluorine-doped tin oxide (FTO) film. Because the Low-E film 41 is a TCO-based thin film, it can be easily disposed on the glass plates 1 and 2. Furthermore, because TCO-based thin films are transparent, the coated region 42 of the glass panel 100 can be made transparent. This reduces the impact of the exposed region 43 on the appearance of the glass panel 100.

(4) In the above embodiment, an example was shown in which the entire outer periphery of the exposed region 43 is formed at a position surrounded by the coated region 42. However, as shown in FIG. 13 , the exposed region 43 may be an exposed region 43A arranged at a corner of the surface of the glass plates 1 and 2 inside the frame, an exposed region 43B adjacent to one side of the surface of the glass plates 1 and 2, or an exposed region 43C whose longitudinal direction is the up-down direction. Furthermore, the exposed region 43 is not limited to a rectangular shape, and may be a circle including an ellipse or an oval, a triangle, a polygon with 5 or more sides, etc.

The present invention can be applied to double-glazed glass panels in which a Low-E film is formed on the glass sheets.

1: First glass plate 2: Second glass plate 3: Air gap layer 5: Spacer 11: First surface 12: Second surface 12a: Outer edge 13: Third surface 13a: Outer edge 41: Low-E film 42: Coated region 43: Exposed region 43A: Exposed region 43B: Exposed region 43C: Exposed region 43a: Outer edge 51: Heat-shielding film 60: Antenna 100: Glass panel (multi-layer glass panel)

Claims (20)

A first glass plate;
a second glass plate disposed opposite the first glass plate;
a spacer disposed between the first glass plate and the second glass plate and forming a gap layer between the first glass plate and the second glass plate,
a coated region on a surface of at least one of the first glass plate and the second glass plate, where a Low-E film is formed, and an exposed region on which the Low-E film is not formed;
the exposed area is rectangular;
the distance between the outer edge of the exposed region and the outer edge of the plate surface having the Low-E film is within 15 cm;
an antenna is provided at a position overlapping a corresponding area of either the first glass plate or the second glass plate that corresponds to the exposed area when viewed from a direction perpendicular to the first glass plate and the second glass plate;
The exposed area is configured to allow passage of radio waves corresponding to ultra-high frequencies (3 to 30 GHz, 100 mm to 10 mm),
A double-glazed glass panel , wherein the distance from the lower end of the corresponding area to the lower end of the antenna is 10 mm or more . When the first glass plate is on the outdoor side, and a plate surface of the first glass plate opposite to the air gap layer is defined as a first surface, a plate surface of the first glass plate on the air gap layer side is defined as a second surface, a plate surface of the second glass plate on the air gap layer side is defined as a third surface, and a plate surface of the second glass plate opposite to the air gap layer is defined as a fourth surface,
2. The double-glazing panel according to claim 1, wherein the coated area and the exposed area are located on the second surface of the first glass sheet or the third surface of the second glass sheet. the Low-E film is disposed on the second surface of the first glass plate;
The double-glazing panel according to claim 2 , wherein a heat-shielding film is disposed on the first surface of the first glass plate, the third surface of the second glass plate, or the fourth surface of the second glass plate. the Low-E film is disposed on the third surface of the second glass plate;
3. The double-glazing panel according to claim 2, wherein a heat-shielding film is disposed on the second surface of the first glass sheet. The double-glazed glass panel according to claim 3 or 4, wherein the heat-shielding film is a heat-absorbing film. The double-glazed glass panel according to claim 3 or 4, wherein the surface resistivity of the heat-shielding film is 20 Ω or more. the plate surface having the Low-E film has at least one exposed area;
7. A double glazing panel according to any preceding claim, wherein the exposed area is greater than an area of 10 cm square and less than an area of 60 cm square. The double-glazed glass panel according to claim 7, wherein the panel surface having the Low-E film has only one exposed area. A double-glazed glass panel according to any one of claims 1 to 8, wherein the difference in visible light transmittance between the coated area and the exposed area, calculated in accordance with JIS R3106 (1998), is less than 10%. In the coated region and the exposed region,
10. The insulating glazing panel of claim 9, wherein the difference in visible light transmittance is less than 5%. A double-glazed glass panel according to any one of claims 1 to 10, wherein the difference in reflected color tone between the coated area and the exposed area, calculated in accordance with JIS Z8781-4 (2013) based on observation from the outside of the room, is within 10 for a* and within 10 for b* on the CIE L*a*b* chromaticity coordinate diagram. In the coated region and the exposed region,
12. The insulating glass panel according to claim 11, wherein the difference in reflected color tone is within 5 in a* and within 5 in b* on the CIE L*a*b* chromaticity coordinate diagram. A double-glazed glass panel according to any one of claims 1 to 12, wherein the Low-E film is a conductive thin film. The double-glazed glass panel according to claim 13, wherein the surface resistivity of the conductive thin film is less than 20 Ω. A double-glazed glass panel according to any one of claims 1 to 14, wherein the Low-E film contains a metal layer whose main component is silver. The double-glazed glass panel described in claim 15, wherein the metal layer has a thickness of 5 nm or more and 15 nm or less. the Low-E film has a first antireflection layer on the inner side of the metal layer, closer to the plate surface on which the Low-E film is formed;
17. The double-glazing panel according to claim 16, wherein the total optical thickness of the first antireflection layer is 60 nm or more and 120 nm or less. the Low-E film has a second antireflection layer on the outer side of the metal layer, away from the plate surface on which the Low-E film is formed;
17. The double-glazing panel according to claim 16, wherein the total optical thickness of the second antireflection layer is 60 nm or more and 120 nm or less. The double-glazed glass panel according to claim 13 or 14, wherein the conductive thin film is a TCO-based thin film. 20. The double glazing panel according to claim 1, wherein the exposed area is an area where the antenna can be installed.