Glass body

Abstract

To provide a glass body having radio wave transmission capable of expanding a reception area.SOLUTION: A glass body 100 includes a first glass plate 1 having a first surface, and a second surface 12 opposite to the first surface, wherein at least one plate surface of the first surface and the second surface 12 includes a radio wave transmission region 43 capable of transmitting a radio wave having a straight-advancing wavelength, the radio wave transmission region 43 has a plurality of radio wave transmission parts 43A which transmit a radio wave and are separated from each other, and a conductive film part 43B formed with a conductive film having radio wave shielding property between the adjacent radio wave transmission part 43A, and the radio wave transmission region 43 is composed of such a radio wave diffusion structure that a part of the radio waves having transmitted through the plurality of radio wave transmission parts 43A diffracts, and is mutually superposed in a space opposite to the conductive film part 43B.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a glass body.

Background Art

[0002] There is known a glass body having heat insulation or heat shielding properties, in which a Low-E film (low-emissivity film) is formed on the plate surface of window glass for vehicles or buildings (see, for example, Patent Document 1). This Low-E film has a problem that it has low permeability (has blocking properties) to radio waves in a frequency band of several hundred MHz to several tens of GHz.

[0003] Therefore, the glass body described in Patent Document 2 provides an opening formed of a plurality of parallel lines in the Low-E film, and by defining the ratio of the length of the plurality of lines to the area of the Low-E film, the radio wave permeability is increased with respect to radio waves in a frequency band of several hundred MHz to several tens of GHz.

[0004] Further, the glass body described in Patent Document 3 is provided in a first film region having a Low-E film composed of a plurality of discontinuous islands, and this first film region has radio wave permeability. Further, Patent Document 3 discloses an embodiment of a multilayer glass panel in which a first film region is provided on the second surface of a first glass plate, and an antenna is provided at a position facing the first film region on the fourth surface of a second glass plate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The 700MHz to 30GHz radio waves included in the frequency band used by the fourth-generation mobile communication system (hereinafter referred to as "4G") and the fifth-generation mobile communication system (hereinafter referred to as "5G") have higher directivity compared to radio waves in lower frequency bands. The aperture described in Patent Document 2 and the first film region described in Patent Document 3 are set in a shape that ensures this directivity of radio waves. In particular, the aperture described in Patent Document 2 has multiple parallel lines provided in the Low-E film, making it easily visible as a striped pattern, which has a significant impact on the appearance. Furthermore, because 4G and 5G have high directivity, on the indoor side, the radio waves tend to weaken in areas other than the space facing the aperture when radio waves are coming from an outdoor base station, making it difficult to receive radio waves. For this reason, it is necessary to improve the indoor communication environment for radio waves with high directivity.

[0007] Therefore, there is a need for a glass material with radio wave transparency that can expand the reception area. [Means for solving the problem]

[0008] The characteristic configuration of the glass body according to the present invention is a first glass plate having a first surface and a second surface opposite to the first surface, wherein at least one of the plate surfaces, the first surface and the second surface, includes a radio wave transmitting region through which radio waves having a straight-traveling wavelength can pass, the radio wave transmitting region has a plurality of spaced-apart radio wave passing portions that allow the radio waves to pass through, and conductive film portions in which a conductive film that blocks the radio waves is formed between adjacent radio wave passing portions, and the radio wave transmitting region is configured as a radio wave diffusion structure in which a portion of the radio waves that have passed through the plurality of radio wave passing portions are diffracted and overlap in the space opposite to the conductive film portion.

[0009] As mentioned above, for example, radio waves in the 700MHz to 3.5GHz frequency band of 4G and the 3.6GHz to 30GHz frequency band of 5G have high directivity, and the radio wave intensity of radio waves passing through the glass is high in the area facing the region of the first glass plate that does not have a conductive film. On the other hand, in order to enlarge the radio wave reception area, it would be possible to omit the conductive film from the glass, but in that case, the heat insulation and heat shielding properties (hereinafter referred to as "heat insulation performance") would be lost, resulting in a trade-off relationship between heat insulation performance and radio wave transparency.

[0010] In this configuration, the glass body has multiple spaced-apart radio wave-transmitting sections that allow radio waves to pass through in the radio wave-transmitting region, and conductive film sections between adjacent radio wave-transmitting sections. In other words, by providing conductive film sections even in the radio wave-transmitting region, the heat insulation performance is enhanced, and by providing multiple radio wave-transmitting sections, radio wave transparency is improved.

[0011] Furthermore, the radio wave-transmitting region of this configuration is composed of a radio wave diffusion structure in which a portion of the radio waves that pass through multiple radio wave-transmitting sections are diffracted and overlap in the space opposite the conductive film section. In other words, the radio waves that pass through the radio wave-transmitting sections not only travel in a straight line but also diffract, and the radio wave diffraction components overlap in the space opposite the conductive film section. This makes it possible to increase the radio wave intensity in the space opposite the conductive film section, where radio wave intensity tends to be weaker, and thus expand the radio wave reception area. In this way, the glass body has radio wave transparency that allows for an expanded reception area.

[0012] Another characteristic feature is that the maximum length of the line segment passing through the center of the radio wave-transmitting section is four times or less the wavelength.

[0013] For example, we found that if the radio wave-passing section is rectangular with a side length of 100 mm, the radio wave diffraction component with a wavelength of 25 mm or more (frequency band of approximately 12 GHz or less) increases. As in this configuration, by setting the maximum length of the line segment passing through the center of the radio wave-passing section to four times the wavelength or less, it is possible to determine the dimensions of the radio wave-passing section that can increase radio wave intensity over a wide reception area, depending on the frequency band used.

[0014] Another characteristic feature is that the width of the conductive film portion that is the shortest distance between adjacent radio wave passing portions is between 10 mm and 500 mm.

[0015] As in this configuration, if the width of the conductive film portion that is the shortest distance between adjacent radio wave passing portions is between 10 mm and 500 mm, both thermal insulation performance and radio wave transparency can be achieved. However, if the width of the conductive film portion is less than 10 mm, the radio wave blocking performance of the conductive film portion decreases, and the entire radio wave transmission region becomes a unified radio wave transparency, thus reducing the radio wave diffraction component. If the width of the conductive film portion is greater than 500 mm, a dead space where there is no overlap of radio waves is likely to occur in the space near the first glass plate.

[0016] Another characteristic feature is that at least one of the plate surfaces includes a radio wave non-transmissive region where the conductive film is formed around the radio wave transparent region, and the radio wave passing portion has a pattern formed having a plurality of islands covered with the conductive film that are spaced apart from each other.

[0017] As in this configuration, if a pattern is formed in the radio wave-transmitting portion having multiple islands covered with conductive films spaced apart from each other, the visual impact between the radio wave-impermeable region and the radio wave-transmitting region can be reduced.

[0018] Another characteristic feature is that a fine line having a line width of 1 μm to 100 μm is formed between adjacent islands, and the distance between adjacent fine lines is 200 μm to 10 mm.

[0019] In a configuration like this, between adjacent islands, there are fine lines with a line width of 1 μm or more and 100 μm or less. If the interval between adjacent fine lines is 200 μm or more and 10 mm or less, while ensuring radio wave permeability, the impact on appearance can be minimized. If the line width of the fine lines is less than 1 μm, it becomes difficult to insulate between adjacent islands, making it difficult to ensure radio wave permeability. If it exceeds 100 μm, the heat insulation performance is likely to deteriorate. Also, if the interval between adjacent fine lines is less than 200 μm, the heat insulation performance deteriorates, and if it exceeds 10 mm, the radio wave permeability is likely to deteriorate.

[0020] As another characteristic configuration, the island is rectangular.

[0021] If the island is rectangular as in this configuration, patterning processing is easy.

[0022] As another characteristic configuration, the wavelength is 10 mm or more and 428 mm or less.

[0023] If the wavelength is 10 mm or more and 428 mm or less (frequency band is 700 MHz or more and 30 GHz or less) as in this configuration, the straightness is particularly high, so the usefulness of adopting the glass body with the above configuration can be enhanced.

[0024] As another characteristic configuration, the conductive film is a Low-E film.

[0025] If the conductive film is a Low-E film as in this configuration, while enhancing the heat insulation performance, it is possible to ensure radio wave permeability that can expand the reception area.

[0026] As another characteristic configuration, it further includes a second glass plate having a third surface facing the second surface and a fourth surface on the opposite side of the third surface, and a spacer that contacts the second surface and the third surface and forms a void layer between the first glass plate and the second glass plate, and the radio wave transmission region is formed on the second surface or the third surface.

[0027] In a double-glazed glass structure like the one described, the thermal insulation performance is enhanced by placing a Low-E film on the second surface of the first glass pane or on the third surface of the second glass pane. In this glass structure with enhanced thermal insulation performance, the usefulness of adopting the glass structure described above can be increased by forming a radio wave transmitting region on the second or third surface. [Brief explanation of the drawing]

[0028] [Figure 1] This is a conceptual diagram of a structure equipped with a glass body according to this embodiment. [Figure 2] This is a side cross-sectional view of the glass body in the first embodiment. [Figure 3] This is a side cross-sectional view of the glass body in the second embodiment. [Figure 4] This is a front view of a glass body having a radio wave transmission region according to this embodiment. [Figure 5] This figure shows the simulation results of radio waves passing through the aperture in the comparative example. [Figure 6] This figure shows the simulation results of radio waves passing through the radio wave transmission region in this embodiment. [Figure 7] This figure shows the simulation results of radio waves passing through the radio wave transmission region in this embodiment. [Figure 8] This figure shows the simulation results of radio waves passing through the radio wave transmission region in this embodiment. [Figure 9] This figure shows the spread of radio waves passing through the aperture in Comparative Example 1. [Figure 10] This figure shows the spread of radio waves passing through the aperture in Comparative Example 2. [Figure 11] This figure shows the spread of radio waves passing through the aperture in Comparative Example 3. [Figure 12] This figure shows the spread of radio waves passing through the radio wave transmission region in this embodiment. [Figure 13] This figure shows the spread of radio waves passing through the aperture when multiple glass bodies of Comparative Example 3 are arranged side by side in the direction of the plate surface. [Figure 14]This figure shows the spread of radio waves passing through the radio wave transmission region when multiple glass bodies of this embodiment are arranged side by side in the direction of the plate surface. [Figure 15] This is an enlarged front view of a glass body having a radio wave transmitting region in another embodiment. [Modes for carrying out the invention]

[0029] Embodiments of the glass body according to the present invention will be described below with reference to the drawings. However, the invention is not limited to the embodiments described below, and various modifications are possible without departing from the spirit of the invention.

[0030] The glass body 100 in this embodiment can be used for various purposes, for example, as window glass in buildings, automobiles, aircraft, ships, trains, and other moving objects. Figure 1 shows a schematic diagram in which the glass body 100 is used as window glass in a building. The glass body 100 may be window glass that is in contact with the outside air, or window glass that partitions the interior of a room.

[0031] As shown in Figure 1, the glass body 100 comprises a first glass plate 1 having a rectangular outer shape. The glass body 100 includes a radio wave-transmitting region 43 through which radio waves corresponding to the entire or partial frequency band of the 4G frequency band of 700 MHz to 3.5 GHz (wavelength 428 mm to 85 mm) and the 5G frequency band of 3.6 GHz to 30 GHz (wavelength 83 mm to 10 mm), which have straight-line propagation, can pass, and a radio wave-impermeable region 42 around the radio wave-transmitting region 43 where a Low-E film 41 (an example of a conductive film) is formed. In this embodiment, the radio wave-transmitting region 43 has a radio wave diffusion structure in which a portion of the radio waves are diffracted to expand the radio wave reception area. Details of the radio wave-transmitting region 43 will be described later.

[0032] The material of the first glass plate 1 (and the second glass plate 2 described later) is not particularly limited, and any known glass plate can be used. For example, various glass plates such as heat-absorbing glass, clear glass, green glass, UV green glass, and soda-lime glass can be used. The thickness of the first glass plate 1 is not particularly limited, but is preferably 2 to 15 mm, and more preferably 2.5 to 8 mm.

[0033] <First Embodiment: Single-Pane Glass> As shown in Figure 2, the first glass plate 1 has a first surface 11 and a second surface 12 opposite to the first surface 11. A Low-E film 41 (an example of a conductive film) having radio wave blocking properties is formed on the second surface 12 of the first glass plate 1. The Low-E film 41 is a conductive thin film that blocks radio waves. Preferably, the surface resistivity of the conductive thin film is less than 20 Ω. In this case, the Low-E film 41 has high reflectivity in the wavelength range from the infrared region to the radio wave region (frequency band of several hundred MHz to several tens of GHz). Therefore, the surface of the first glass plate 1 on which the Low-E film 41 is formed has low radio wave transmittance but also low emissivity. The second surface 12 of the first glass plate 1 has a radio wave non-transmissive region 42 on which the Low-E film 41 is formed over the entire surface. Furthermore, a radio wave transparent region 43 is provided on a part of the second surface 12, which is the plate surface on which the Low-E film 41 is formed (the central part in the figure), where a part of the Low-E film 41 has been removed by laser processing or the like. This radio wave transparent region 43 is arranged to allow the transmission of radio waves corresponding to the entire or a part of the frequency band of 4G, which has straight-line propagation, from 700 MHz to 3.5 GHz (wavelength 428 mm to 85 mm), and the frequency band of 5G, from 3.6 GHz to 30 GHz (wavelength 83 mm to 10 mm). Note that a radio wave non-transparent region 42 and a radio wave transparent region 43 may also be provided on the first surface 11 of the first glass plate 1.

[0034] <Second Embodiment: Double Glazing> As shown in FIG. 3, the glass body 100 is a multi-layer glass having two glass plates with substantially the same rectangular outer shape on the plate surface, that is, a first glass plate 1 and a second glass plate 2. A pair of glass plates 1 and 2 are connected to each other by a spacer 5 disposed at their peripheral portions. A void layer 3 is formed between the pair of glass plates 1 and 2 by the spacer 5. The first glass plate 1 has a first surface 11 which is the plate surface on the outdoor side and a second surface 12 which is the plate surface on the side of the void layer 3 opposite to the first surface 11. The second glass plate 2 has a third surface 13 which is the plate surface on the side of the void layer 3 and a fourth surface 14 which is the plate surface on the indoor side opposite to the third surface 13. That is, the spacer 5 is in contact with the second surface 12 and the third surface 13. A Low-E film 41 (an example of a conductive film) having radio wave shielding properties is formed on the plate surface (second surface 12) on the side of the void layer 3. Although not shown, the void layer 3 is sealed by a frame body in which a sealing material is disposed outside the spacer 5.

[0035] The second surface 12 of the first glass plate 1 has a radio wave non-transmission region 42 in which the Low-E film 41 is formed over the entire area. Further, a radio wave transmission region 43 in which a part of the Low-E film 41 is removed by laser processing or the like is provided on the second surface 12 which is the plate surface on which the Low-E film 41 is formed. This radio wave transmission region 43 is arranged to enable the transmission of radio waves corresponding to the entire band or a part of the band of the 4G frequency band having linearity, which is 700 MHz to 3.5 GHz (wavelength 428 mm to 85 mm), or the 5G frequency band of 3.6 GHz to 30 GHz (wavelength 83 mm to 10 mm). In a multi-layer glass as in the present embodiment, the heat insulation performance is enhanced if the Low-E film 41 is disposed on the second surface 12 of the first glass plate 1 or the third surface 13 of the second glass plate 2. Further, the radio wave non-transmission region 42 and the radio wave transmission region 43 may be provided on the first surface 11 of the first glass plate 1 or the fourth surface 14 of the second glass plate 2. Further, an antenna (not shown) for radio wave transmission and reception may be installed on the indoor side plate surface (fourth surface 14) of the glass body 100, or an antenna may be installed on the indoor ceiling or the like.

[0036] <Low-E film> The Low-E film 41 is not particularly limited as long as it does not hinder the objectives of the present invention, but is preferably a multilayer film including a layer mainly composed of silver. It is also preferable that the Low-E film 41 consists of a multilayer formed by laminating two or more layers selected from a metal layer, a metal oxide layer, a metal nitride layer, and a metal oxynitride layer. A preferred example of a metal layer is a silver layer. A preferred example of a metal oxide layer is a tin oxide layer, a titanium oxide layer, or a zinc oxide layer. A preferred example of a metal nitride layer is silicon nitride. A preferred example of a metal oxynitride layer is silicon oxynitride. The Low-E film 41 is preferably deposited using a vacuum deposition method such as physical vapor deposition (PVD), and sputtering is particularly preferred because it can uniformly deposit a film over a large area. The radio wave transparent region 43 is formed, for example, by depositing 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 radio wave transparent region 43 may also be formed using various masking materials. By forming the radio wave-transmitting region 43 using this method, it can be easily positioned at a desired location on the glass plate.

[0037] Furthermore, the Low-E film 41 is more preferably a multilayer formed by laminating 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, it consists of three or five layers, arranged sequentially from the surface of the glass plate: (1) a tin oxide layer (first anti-reflective layer), a zinc oxide layer (first anti-reflective layer), a silver layer (metal layer), a zinc oxide layer (second anti-reflective layer), and a tin oxide layer (second anti-reflective layer), and (2) a silicon nitride layer (first anti-reflective layer), a zinc oxide layer (first anti-reflective layer), a silver layer (metal layer), and a zinc oxide layer (second anti-reflective layer).

[0038] The Low-E film 41 contains a metal layer mainly composed of silver. The thickness of the metal layer is preferably 5 nm to 20 nm, and more preferably 10 nm to 15 nm. By having a metal layer of a predetermined thickness mainly composed of silver in the Low-E film 41, heat radiation can be suppressed. As a result, the heat insulation performance of the glass body 100 can be improved. Furthermore, by having a metal layer thickness of 15 nm or less, the visual impact of the Low-E film 41 can be minimized.

[0039] The Low-E film 41 preferably has a first anti-reflective layer on the inside 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-reflective layer is preferably 20 nm or more and 120 nm or less. The Low-E film 41 preferably has a second anti-reflective layer on the outside of the metal layer, further from the plate surface on which the Low-E film 41 is formed, and the total optical thickness of the second anti-reflective layer is preferably 60 nm or more and 120 nm or less. The optical thickness can be calculated by (refractive index n) × (thickness d). If the first anti-reflective layer (second anti-reflective layer) is composed of multiple films, the sum of the optical thicknesses calculated for each film becomes the optical thickness of the first anti-reflective layer (second anti-reflective 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 general reference wavelength in the visible range (550 nm).

[0040] As described above, the Low-E film 41 has low reflectivity because the metal layer is protected by the presence of a first anti-reflective layer of a predetermined thickness on the side of the first glass plate 1 closer to the second surface 12, relative to the metal layer, thereby ensuring reliable heat insulation. Furthermore, the glass body 100 can achieve high visible light transmittance and a suitable reflective color tone.

[0041] Furthermore, even when a second anti-reflective layer of a predetermined thickness exists on the side of the second surface 12 of the first glass plate 1 that is farther from the metal layer, the Low-E film 41 protects the metal layer and the Low-E film 41 has low reflectivity, thus reliably blocking heat. In addition, a high visible light transmittance and a suitable reflective color tone can be achieved in the glass body 100.

[0042] <Radio wave transmission area> As shown in Figure 4, the radio wave non-transmissive region 42 in this embodiment is a region in which a Low-E film 41 is formed around the radio wave transparent region 43, and the radio wave transparent region 43 has a radio wave diffusion structure in which a portion of the radio waves diffract to expand the radio wave reception area. The radio wave transparent region 43 has a plurality of spaced-apart (25 in this embodiment, 5 x 5) radio wave passing sections 43A that allow radio waves with straight-directivity wavelengths (10 mm to 500 mm) to pass through, and conductive film sections 43B in which a radio wave blocking Low-E film 41 is formed between adjacent radio wave passing sections 43A. This radio wave transparent region 43 is composed of a radio wave diffusion structure in which a portion of the radio waves that have passed through the plurality of radio wave passing sections 43A diffract and overlap in the space opposite to the conductive film sections 43B.

[0043] In this embodiment, the radio wave passing section 43A is formed in a rectangular shape, and the longest of the four sides is four times or less the wavelength of the radio wave passing through (10 mm to 500 mm, hereinafter simply referred to as "wavelength"). In other words, the maximum length L of the line segment passing through the center of the radio wave passing section 43A (direction of electric field oscillation of the polarized radio wave) is four times or less the wavelength. By setting the maximum length L of the line segment passing through the center of the radio wave passing section 43A to four times or less the wavelength, the dimensions of the radio wave passing section 43A can be determined to increase the radio wave intensity over a wide reception area depending on the frequency band used. On the other hand, for radio waves corresponding to the 5G (millimeter wave) frequency band of 30 GHz to 300 GHz (wavelength less than 11 mm), processing the radio wave passing section 43A becomes difficult, and therefore it is not a desirable radio wave diffusion structure according to this embodiment. In such cases, the wavelength of the radio wave passing through may be set to 10 mm or more, or it may be limited to the 5G (sub6 band) wavelength of 49 mm or more (frequency band of 6 GHz or less). In this embodiment, since the radio wave transmission section 43A is a square, all four sides are equal to the maximum length L of the line segment passing through the center of the radio wave transmission section 43A. However, if it is a rectangle, the two longer sides of the four sides will be equal to the maximum length L of the line segment passing through the center of the radio wave transmission section 43A.

[0044] Furthermore, the maximum length L of the line segment passing through the center of the radio wave-transmitting section 43A is preferably 10 mm or more and 4 times or less the wavelength, and more preferably 20 mm or more and 2 times or less the wavelength. Note that if the maximum length L of the line segment passing through the center of the radio wave-transmitting section 43A is less than 10 mm, the patterning process described later becomes difficult, and if it exceeds 4 times the wavelength, the radio wave diffraction component decreases, making it difficult to increase the radio wave intensity over a wide reception area.

[0045] The width W of the conductive film portion 43B that is the shortest distance between adjacent radio wave passing portions 43A is preferably 10 mm or more and 500 mm or less, and more preferably 10 mm or more and 100 mm or less. In this way, if the width W of the conductive film portion 43B that is the shortest distance between adjacent radio wave passing portions 43A is 10 mm or more and 500 mm or less, both thermal insulation performance and radio wave transparency can be achieved. However, if the width W of the conductive film portion 43B is less than 10 mm, the radio wave blocking performance by the conductive film portion 43B decreases, and the entire radio wave transmission region 43 becomes a unified radio wave transparency, so the radio wave diffraction component decreases. If the width W of the conductive film portion 43B is greater than 500 mm, a dead space in the vicinity of the first glass plate 1 where there is no overlap of radio waves is likely to occur.

[0046] Each radio wave-transmitting section 43A has a pattern formed with multiple islands 43Aa covered with spaced-apart Low-E films 41. The radio wave-transmitting section 43A is formed by, for example, depositing a Low-E film 41 on a glass plate by sputtering, and then removing only the Low-E film 41 by laser processing or the like, thereby forming fine lines 43Ab between adjacent islands 43Aa. By forming fine lines 43Ab in this way, the glass plate is not scratched, and the fine lines 43Ab can be made less noticeable. In this embodiment, the multiple islands 43Aa are formed in a symmetrical shape, spaced equally apart from each other via fine lines 43Ab having the same line width.

[0047] The line width of the fine wire 43Ab is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 30 μm or less. If the line width of the fine wire 43Ab is less than 1 μm, it becomes a single Low-E film 41, making it difficult to insulate adjacent islands 43Aa from each other, thus making it difficult to ensure radio wave transparency. If it is greater than 100 μm, the thermal insulation performance tends to decrease.

[0048] The spacing between adjacent nanowires 43Ab (the distance between the centers of adjacent nanowires 43Ab) is preferably 200 μm or more and 10 mm or less, and more preferably 500 μm or more and 3 mm or less. Furthermore, if the spacing between adjacent nanowires 43Ab is less than 200 μm, the thermal insulation performance will decrease, and if it is greater than 10 mm, the radio wave transmittance will tend to decrease. The upper limit of the spacing between adjacent nanowires 43Ab is preferably one-third of the wavelength or less.

[0049] <Evaluation Test> (Test conditions) A soda-lime glass first glass plate 1 with a thickness of 6 mm was used, and the Low-E film 41 covering the second surface 12 was made of SnO2 / ZnO / Ag / SUS / ZnO / SnO2 from the second surface 12 side of the first glass plate 1, with a total film thickness of 80 nm and an emissivity of 0.1. The laser processing conditions for removing the Low-E film 41 were set to remove only the Low-E film 41 without removing the glass, using a YAG:Nd laser with a repetition rate of 100 kHz, a wavelength of 355 nm, and an operating speed of 300 mm / sec.

[0050] (Emissivity) The emissivity was measured using a Fourier transform infrared spectrometer (Perkin Elmer Frontier Gold) in accordance with JIS-R3106. Table 1 shows the emissivity of the radio wave-transmitting sections 43A when the number and size of the radio wave-transmitting sections 43A, and the line width and spacing of the thin wires 43Ab are varied. All radio wave-transmitting sections 43A and islands 43Aa were formed as squares, and the width of the conductive film section 43B, which is the shortest distance between adjacent radio wave-transmitting sections 43A, was set to 50 mm. [Table 1]

[0051] As shown in test number (3) in Table 1, it can be seen that if the line width of the fine wire 43Ab is greater than 100 μm, the emissivity of the radio wave-transmitting portion 43A deteriorates significantly, and the thermal insulation performance decreases. Furthermore, as shown in test numbers (1), (2), (4), (5), and (6), it can be seen that regardless of the number or size of the radio wave-transmitting portions 43A, if the line width of the fine wire 43Ab is 100 μm or less and the spacing between the fine wires 43Ab is 200 μm or more, the deterioration of emissivity is suppressed and thermal insulation performance is maintained compared to the case where the entire surface of the first glass plate 1 is covered with the Low-E film 41.

[0052] (Radio wave transmission characteristics) Next, simulation results demonstrating that the radio wave transmission region 43 of the glass body 100 in this embodiment has a radio wave diffusion structure in which a portion of the radio waves are diffracted to expand the radio wave reception area will be described. Figures 5 to 14 show the simulation results confirming the radio wave transmission characteristics of the glass body 100 according to this embodiment and the glass body according to the comparative example. Figures 5 to 8 were calculated using the Micro-Stripes2 high-frequency electromagnetic field simulator, and Figures 9 to 14 were calculated using the Altair Feko high-frequency electromagnetic field simulator. Furthermore, Figures 5 to 12 represent perpendicular incidence, where the radio waves are incident perpendicularly to the first surface 11 of the first glass plate 1, while Figures 13 and 14 represent oblique incidence, where the radio waves are incident at an angle to the first surface 11 of the first glass plate 1.

[0053] Figures 5 to 8 show the simulation results from a plan view (top edge of the aperture) of the radio wave transmission region 43A, which has a 100 mm × 100 mm aperture (maximum length L of the line segment passing through the center is 100 mm). A simulation was performed in which radio waves from 30 GHz to 1 GHz (wavelength 10 mm to 300 mm) were irradiated onto this radio wave transmission region 43A. The area enclosed by the dashed line in the figure shows the distribution of strong radio waves (radio wave transmission loss of 10 dB or less when the incident radio wave is set to 0 dB).

[0054] As shown in Figure 5 as a comparative example, in the relatively high frequency band of 30 GHz to 15 GHz (wavelength 10 mm to 20 mm), it can be seen that the radio waves passing through the radio wave-passing section 43A travel in a straight line with almost no diffraction. On the other hand, as shown in Figure 6 as an embodiment, in the relatively low frequency band of 10 GHz to 1 GHz (wavelength 30 mm to 300 mm), it can be seen that the radio waves passing through the radio wave-passing section 43A are diffracted so as to spread into the space opposite the conductive film section 43B.

[0055] Figures 7 and 8 show the overlap of radio waves passing through adjacent radio wave-transmitting sections 43A when the width W of the conductive film section 43B is set to 50 mm. As shown in Figure 7, in the frequency band of 5 GHz (wavelength 60 mm), there is a wide overlap in the space opposite the conductive film section 43B. In the frequency band of 10 GHz (wavelength 30 mm), although the degree of overlap decreases slightly, it can be understood that the radio wave-transmitting region 43 is composed of a radio wave diffusion structure in which some of the radio waves that have passed through multiple radio wave-transmitting sections 43A are diffracted and overlap in the space opposite the conductive film section 43B. As shown in Figure 8, in the lower frequency band of 3 GHz to 1 GHz (wavelength 100 mm to 300 mm), there is a wide overlap in the space opposite the conductive film section 43B. From these, it can be seen that it is preferable for the wavelength of the radio waves (30 mm to 300 mm) to be greater than one-quarter of the aperture length of 100 mm (maximum length L of the line segment passing through the center). In other words, it is preferable that the radio wave-transmitting section 43A is four times the wavelength or less. Furthermore, it is even more preferable that the wavelength of the radio waves (60 mm to 300 mm) is greater than half the aperture length of 100 mm (the maximum length L of the line segment passing through the center). In this case, the radio wave passing portion 43A will be less than or equal to twice the wavelength.

[0056] Figures 9 to 12 show the simulation results of the spread of radio waves in a space 1 m away from the second surface 12 of the first glass plate 1 (indicated by a dashed line in the figures) when radio waves with a frequency band of 3.5 GHz (wavelength 86 mm) are incident perpendicularly from the first surface 11 of the first glass plate 1. Figure 9 shows Comparative Example 1 in which the entire second surface 12 of the first glass plate 1 is covered with a Low-E film 41. Figure 10 shows Comparative Example 2 having one 100 mm × 100 mm opening formed by removing the Low-E film 41 in the center of the second surface 12 of the first glass plate 1. Figure 11 shows Comparative Example 3 having one 500 mm × 500 mm opening formed by removing the Low-E film 41 in the center of the second surface 12 of the first glass plate 1. Figure 12 shows an embodiment in which, as with the glass body 100 according to the embodiment described above, 5 x 5 100 mm x 100 mm radio wave passing sections 43A are arranged to form a total radio wave transparent area 43 of 500 mm x 500 mm in the center of the second surface 12 of the first glass plate 1.

[0057] In Comparative Example 1 shown in Figure 9, radio waves were blocked, and the radio wave transmission loss was 30 dB or more, so almost no radio waves were received on the second surface 12 side of the first glass plate 1. In Comparative Example 2 shown in Figure 10, only radio waves that traveled straight from the aperture were present, and there was no spread of radio waves at all. In Comparative Example 3 shown in Figure 11, the aperture length was 500 mm, which is more than four times the radio wave wavelength of 86 mm, so there was almost no spread of radio waves. On the other hand, in this embodiment shown in Figure 12, the radio wave transmission loss expanded to a range of 3 dB to 15 dB, and although the radio wave intensity decreased slightly, the radio wave reception area was expanded.

[0058] Figures 13 and 14 show the simulation results of the radio wave propagation when four first glass plates 1 are arranged side by side in the direction of the plate surface. Specifically, Figures 13 and 14 show the propagation of radio waves in a region R (shown as a dashed line in the figures) formed horizontally along the xy plane when radio waves with a frequency band of 3.5 GHz (wavelength 86 mm) are obliquely incident on each first glass plate 1 from the first surface 11 towards the second surface 12 at a rightward incidence angle of 45 degrees. Region R is a rectangular region formed by the first side A where the four first glass plates 1 are arranged side by side and the second side B which is perpendicular to the first side A. In Figures 13 and 14, the length of the first side A is set to 7800 mm and the length of the second side B is set to 5500 mm. Multiple openings (radio wave transmission areas 43) along the first side A are set so that the distance P1 from both ends of the first side A to the opening is 900 mm, and the distance P2 between adjacent openings is set to 1800 mm. In Figure 13, the glass body of Comparative Example 3 is used as the first glass plate 1, which has one 500 mm × 500 mm opening formed by removing the Low-E film 41 in the center of the second surface 12. In Figure 14, the glass body of this embodiment is used as the first glass plate 1, which, like the glass body 100 according to the embodiment described above, has 5 × 5 100 mm radio wave transmission areas 43A arranged in a row to form a total radio wave transmission area 43 of 500 mm × 500 mm in the center of the second surface 12.

[0059] In Figure 13, where the glass body of Comparative Example 3 is used, each radio wave passing through the opening of the first glass plate 1 has a small horizontal spread, so the radio waves only reach about half of region R. On the other hand, in Figure 14, where the glass body of this embodiment is used, each radio wave passing through the radio wave transmission region 43 has a large horizontal spread, so the radio waves spread throughout region R. The following explains this in detail. For region R, draw a virtual diagonal C from the upper left corner to the lower right corner, and define the area to the left of diagonal C as the first region R1 and the area to the right as the second region R2. In this case, in Figure 13, the radio waves passing through the opening of the first glass plate 1 reach the first region R1, but not the area of ​​the second region R2 that is far from diagonal C. On the other hand, in Figure 14, although the radio wave intensity is slightly reduced, it was confirmed that the radio waves spread widely not only to the first region R1 but also to the second region R2, and that the radio waves spread throughout region R.

[0060] Thus, in this embodiment, the glass body 100 has a plurality of spaced-apart radio wave passing sections 43A that allow radio waves to pass through in the radio wave transmission region 43, and conductive film sections 43B are provided between adjacent radio wave passing sections 43A. In other words, by providing conductive film sections 43B in the radio wave transmission region 43, the heat insulation performance is enhanced, and by providing a plurality of radio wave passing sections 43A, radio wave transparency is enhanced.

[0061] Furthermore, the radio wave-transmitting region 43 is composed of a radio wave diffusion structure in which a portion of the radio waves that have passed through the multiple radio wave-transmitting sections 43A are diffracted and overlap in the space opposite the conductive film section 43B. In other words, the radio waves that have passed through the radio wave-transmitting sections 43A not only travel in a straight line but also diffract, and the radio wave diffraction components overlap in the space opposite the conductive film section 43B. As a result, it is possible to increase the radio wave intensity in the space opposite the conductive film section 43B, where the radio wave intensity tends to be weaker, and to enlarge the radio wave reception area. Therefore, the glass body 100 has radio wave transparency that can expand the reception area.

[0062] [Other embodiments] (1) The radio wave transmission region 43 in the above-described embodiment is not limited to a rectangular shape, but may be circular, oval, elliptical, cross-shaped, etc. In this case as well, it is preferable that the maximum length L of the line segment passing through the center of the radio wave transmission portion 43A is 10 mm or more and 4 times or less the wavelength. (2) As shown in Figure 15, the radio wave passing portion 43A of the radio wave transparent region 43 may be formed in an annular shape. In this case as well, it is preferable that the radio wave passing portion 43A is patterned by forming a plurality of fine lines 43Ab concentrically at equal intervals. The various dimensional ranges of the radio wave transparent region 43 are the same as in the embodiments described above. (3) The multiple islands 43Aa formed in the radio wave passing section 43A in the above-described embodiment may be omitted, and the Low-E film 41 may be removed over the entire area of ​​the radio wave passing section 43A. Furthermore, the shape of the islands 43Aa is not limited to a rectangular shape, but may be circular, oval, elliptical, etc. (4) In the radio wave transparent region 43, it is not necessary to remove the Low-E film 41 and expose the glass plate; it is sufficient if at least the silver-based metal layer is removed.

[0063] (5) In the double-glazed glass of the second embodiment, a heat-shielding film may be placed on the second surface 12 of the first glass plate 1, and a Low-E film 41 may be placed on the third surface 13 of the second glass plate 2. The heat-shielding film is preferably a multilayer film including a layer mainly composed of titanium nitride. A suitable example of the metal nitride layer is a titanium nitride layer. The thickness of the heat-shielding film is appropriately selected depending on the type of film to be laminated, but is usually 5 to 100 nm, preferably 10 to 50 nm. The heat-shielding film is composed of, for example, a heat-absorbing film. If the heat-shielding film is a heat-absorbing film, infrared rays can be absorbed by the heat-shielding film, thereby improving the heat-shielding performance of the glass body 100. [Industrial applicability]

[0064] This invention can be used for glass bodies such as windows in buildings, automobiles, aircraft, ships, trains, and other moving objects. [Explanation of Symbols]

[0065] 1: First glass plate 2: Second glass plate 3 :Void layer 5: Spacer 11: 1st page 12:Second side 13:Third side 14:Side 4 41: Low-E film (conductive film) 42:Radio wave non-transparent area 43:Radio wave transmission area 43A: Radio wave passing section 43Aa: Island 43Ab: Thin line 43B: Conductive film part 100: Vitreous body L: Maximum length of the line segment passing through the center W: Width of the conductive film portion

Claims

1. A glass body comprising a first glass plate having a first surface and a second surface opposite to the first surface, wherein at least one of the plate surfaces of the first surface and the second surface includes a radio wave transmission region through which radio waves having a straight-propagating wavelength can pass, the radio wave transmission region having a plurality of radio wave passing portions spaced apart from each other through which the radio waves pass, and a conductive film portion in which a conductive film having radio wave blocking properties is formed between adjacent radio wave passing portions, the radio wave transmission region being composed of a radio wave diffusion structure in which a part of the radio waves passing through the plurality of radio wave passing portions diffracts and overlaps in a space facing the conductive film portion.

2. The glass body according to claim 1, wherein the maximum length of a line segment passing through the center of the radio wave passing portion is 4 times or less the wavelength.

3. The glass body according to claim 1, wherein the width of the conductive film portion, which is the shortest distance between adjacent radio wave passing portions, is 10 mm or more and 500 mm or less.

4. At least one of the plate surfaces includes a radio wave non-transmission region in which the conductive film is formed around the radio wave transmission region, and the radio wave passing portion has a patterning having a plurality of islands covered with the conductive films spaced apart from each other.

5. The glass body according to claim 4, wherein thin lines having a line width of 1 μm or more and 100 μm or less are formed between adjacent islands, and the interval between adjacent thin lines is 200 μm or more and 10 mm or less.

6. The glass body according to claim 4, wherein the island is rectangular.

7. The glass body according to claim 1, wherein the wavelength is 10 mm or more and 428 mm or less.

8. The glass body according to any one of claims 1 to 7, wherein the conductive film is a Low-E film.

9. Further comprising a second glass plate having a third surface facing the second surface and a fourth surface opposite to the third surface, and a spacer that contacts the second surface and the third surface and forms a gap layer between the first glass plate and the second glass plate, wherein the radio wave transmission region is formed on the second surface or the third surface.

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