Vehicle window glass

Abstract

The purpose of the present invention is to improve appearance and ensure antenna characteristics.　This vehicle window glass comprises a glass plate, a light-shielding layer formed on the glass plate, and a planar antenna in which a hollowed-out portion including at least one hole is formed in a planar conductor, wherein where in a plan view of the glass plate, a region having the light-shielding layer is defined as a light-shielding region, and a region having no light-shielding layer is defined as a transmission region, the planar antenna is arranged across the boundary of the light-shielding region and the transmission region and has a first conductor portion that overlaps with the light-shielding region and a second conductor portion that overlaps with the transmission region, and where an area where the planar antenna overlaps with the light-shielding region is defined as a first overlapping area, an area where the planar antenna overlaps with the transmission region is defined as a second overlapping area, the ratio of the area of the first conductor portion to the first overlapping area is defined as a first conductor density, and the ratio of the area of the second conductor portion to the second overlapping area is defined as a second conductor density, the second conductor density is smaller than the first conductor density.

Description

[Technical Field]

[0001] This disclosure relates to vehicle window glass. [Background technology]

[0002] Conventionally, a planar antenna with a grid-like cutout formed in a conductive film is known as an antenna installed on vehicle windows (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2017 / 018324 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] As with the planar antenna described above, if the cutout formed in a planar conductor such as a conductive film becomes larger, the planar antenna becomes less noticeable, which is thought to improve the overall appearance of the window glass. However, if the cutout becomes larger, the area of ​​the conductive portion in the planar conductor becomes smaller, which may make it difficult to ensure the antenna characteristics of the planar antenna.

[0005] This disclosure provides vehicle window glass that can improve appearance and ensure antenna characteristics. [Means for solving the problem]

[0006] According to one aspect of this disclosure, The antenna comprises a glass plate, a light-shielding layer formed on the glass plate, and a planar antenna in which a cutout portion containing at least one void is formed within a planar conductor. In a plan view of the glass plate, when the region having the light-shielding layer is defined as the light-shielding region and the region not having the light-shielding layer is defined as the light-transmitting region, The planar antenna is arranged to straddle the boundary between the light-shielding region and the light-transmitting region, and has a first conductor portion that overlaps with the light-shielding region and a second conductor portion that overlaps with the light-transmitting region. When the area in which the planar antenna overlaps with the light-shielding region is defined as the first overlapping area, the area in which the planar antenna overlaps with the light-transmitting region is defined as the second overlapping area, the ratio of the area of ​​the first conductor portion to the first overlapping area is defined as the first conductor density, and the ratio of the area of ​​the second conductor portion to the second overlapping area is defined as the second conductor density, A vehicle window glass is provided in which the second conductor density is lower than the first conductor density. [Effects of the Invention]

[0007] According to one aspect of this disclosure, it is possible to provide vehicle window glass that can improve appearance and ensure antenna characteristics. [Brief explanation of the drawing]

[0008] [Figure 1] This is an enlarged view showing a portion of the vehicle window glass of the first embodiment in a plan view. [Figure 2] This is an enlarged view showing a portion of the vehicle window glass of the second embodiment in a plan view. [Figure 3] This is an enlarged view showing a portion of the vehicle window glass of the third embodiment in a plan view. [Figure 4] This is an enlarged view showing a portion of the vehicle window glass of the fourth embodiment in a plan view. [Figure 5] This is an enlarged view showing a portion of the vehicle window glass of the fifth embodiment in a plan view. [Figure 6] This figure shows an example of the measured VSWR results for a planar antenna according to the first embodiment. [Figure 7] This figure shows an example of the measured VSWR results for a planar antenna according to the second embodiment. [Figure 8] This figure shows an example of the measured VSWR results for a planar antenna according to the third embodiment. [Figure 9] This figure shows an example of the measured VSWR results for a planar antenna according to the fourth embodiment. [Figure 10]It is a diagram showing an example of the measured VSWR results of the planar antenna of the fifth embodiment. [Figure 11] It is a diagram showing an example of the VSWR results by simulation of another planar antenna of the first embodiment. [Figure 12] It is a diagram showing the dimensions of the planar antenna of the first embodiment in the measurement of VSWR. [Figure 13] It is a diagram showing the dimensions of the planar antenna of the second embodiment in the measurement of VSWR. [Figure 14] It is a diagram showing the dimensions of the planar antenna of the third embodiment in the measurement of VSWR. [Figure 15] It is a diagram showing the dimensions of the planar antenna of the fourth embodiment in the measurement of VSWR. [Figure 16] It is a diagram showing the dimensions of the planar antenna of the fifth embodiment in the measurement of VSWR. [Figure 17] It is a diagram showing the dimensions of another planar antenna of the first embodiment in the VSWR results by simulation. [Figure 18] It is a table showing each condition value at the time of measuring VSWR. [Figure 19] It is a diagram showing an example of the measured antenna gain results of the planar antenna of the second embodiment. [Figure 20] It is a diagram showing an example of the measured antenna gain results of the planar antenna of the fifth embodiment.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described with reference to the drawings. For ease of understanding, the scales of each part in the drawings may be different from the actual ones. In directions such as parallel, right angle, orthogonal, horizontal, vertical, up and down, left and right, and terms such as identical and equal, a deviation that does not impair the actions and effects of the embodiments is allowed.

[0010] Examples of vehicle window glass in this embodiment include a rear window installed at the rear of the vehicle, a windshield installed at the front of the vehicle, side windows installed at the sides of the vehicle, and roof glass installed on the ceiling of the vehicle. Vehicle window glass is not limited to these examples. Hereinafter, in this embodiment, vehicle window glass will also be simply referred to as window glass.

[0011] Figure 1 is an enlarged view showing a portion of a vehicle window glass of the first embodiment in plan view. The window glass 201 shown in Figure 1 is an example of a vehicle window glass. Figure 1 shows an enlarged view of a portion of the peripheral area of ​​the outer edge 64 of the window glass 201. The window glass 201 comprises a glass plate 65, a light-shielding layer 130, and a planar antenna 101.

[0012] The first, second, third, and fourth directions indicate the direction of the glass plate 65 or the planar antenna 101 in a plan view. The third direction indicates the direction opposite to the first direction, and the fourth direction indicates the direction opposite to the second direction. In this embodiment, adjacent directions in the first, second, third, and fourth directions intersect at a right angle (may include approximate right angles). These descriptions can also be applied to other plan views.

[0013] The glass plate 65 is a vehicle glass plate having a main surface 60 and an outer peripheral edge 64. The main surface 60 is, for example, the surface on the inside of the vehicle. The outer peripheral edge 64 corresponds to the outer edge of the main surface 60. The flange end 67 of the vehicle body represents the inner peripheral edge of the flange (window frame) to which the glass plate 65 (window glass 201) is attached. The glass plate 65 may be for a windshield, side glass, rear glass, or roof glass. The glass plate 65 may be a single glass plate, or it may be laminated glass in which multiple glass plates are laminated with an interlayer containing a resin such as polyvinyl butyral (PVB) or ethylene-vinyl acetate copolymer (EVA) sandwiched in between.

[0014] The light-shielding layer 130 is a layer that blocks visible light. The light-shielding layer 130 is formed on the glass plate 65, for example, on the main surface 60 of the glass plate 65. If the glass plate 65 is laminated glass, the light-shielding layer 130 may be formed on the inner main surfaces of the multiple glass plates that make up the laminated glass.

[0015] The light-shielding layer 130 is, for example, an opaque colored ceramic layer with a thickness of about 5 μm to 25 μm. The color of the light-shielding layer 130 is arbitrary, but dark colors such as black, brown, gray, dark blue, or white are preferred, with black being more preferred. Because a portion of the planar antenna 101 overlaps with the light-shielding layer 130 and the glass plate 65 in a planar view, the overlapping portion with the light-shielding layer 130 becomes difficult to see, thus improving the appearance of the window glass 201 equipped with the planar antenna 101.

[0016] The light-shielding layer 130 is, for example, a band-shaped region formed along the outer edge 64. In this case, the inner edge of the light-shielding layer 130 corresponds to the outer edge of the opening (transmitting region 62) of the window glass 201. In a plan view of the glass plate 65, the region having the light-shielding layer 130 is referred to as the light-shielding region 61, and the region not having the light-shielding layer 130 is referred to as the transmittance region 62. The light-shielding region 61 is the region where visible light is blocked by the light-shielding layer 130, and the transmittance region 62 is the region where visible light is not blocked by the light-shielding layer 130.

[0017] The light-shielding layer 130 may include a boundary region 63 in which multiple dots are arranged. The boundary region 63 is a region along the inner edge of the light-shielding layer 130 (the boundary 66 between the light-shielding region 61 and the transparent region 62), and is a gradient region in which the degree of light shielding gradually changes.

[0018] The planar antenna 101 is an example of a planar antenna in which a cutout containing at least one void is formed within a planar conductor, and in this example, a cutout containing multiple voids is formed in a flat conductor 20. The conductor 20 is an example of a planar conductor.

[0019] The planar antenna 101 is positioned so as to straddle the boundary 66 between the light-shielding region 61 and the light-transmitting region 62 in a plan view of the glass plate 65. In the illustrated example, the boundary 66 is macroscopically a straight line, but it may also include curves. In a plan view of the glass plate 65, the planar antenna 101 has a first conductor portion 31 which is the conductor portion of the conductor 20 that overlaps with the light-shielding region 61, and a second conductor portion 32 which is the conductor portion of the conductor 20 that overlaps with the light-transmitting region 62.

[0020] In the example shown in Figure 1, the planar antenna 101 has a first cutout 23 formed in the first conductor portion 31 and a second cutout 24 formed in the second conductor portion 32. The first cutout 23 and the second cutout 24 are non-conducting regions in the conductor 20 where no conductor portion exists. The first cutout 23 is the region where the cutout portion of the conductor 20 overlaps with the light-shielding region 61 in a plan view of the glass plate 65, and in the example shown in Figure 1, it includes a plurality of voids 27 formed in the conductor 20. The second cutout 24 is the region where the cutout portion of the conductor 20 overlaps with the transmission region 62 in a plan view of the glass plate 65, and in the example shown in Figure 1, it includes a plurality of voids 28 formed in the conductor 20.

[0021] The planar antenna 101 is impedance-matched to be suitable for transmitting and receiving (either or both) radio waves in a predetermined frequency band. The shape of the planar antenna is not limited to the shape shown.

[0022] Here, the area where the planar antenna 101 overlaps with the light-shielding region 61 is defined as the first overlapping area S1, and the area where the planar antenna 101 overlaps with the transmission region 62 is defined as the second overlapping area S2. The first overlapping area S1 may be defined as the area where the planar antenna 101 overlaps with the light-shielding region 61, assuming that the planar antenna 101 is a solid planar conductor without any cutouts. Similarly, the second overlapping area S2 may be defined as the area where the planar antenna 101 overlaps with the transmission region 62, assuming that the planar antenna 101 is a solid planar conductor without any cutouts. Furthermore, the ratio of the area of ​​the first conductor portion 31 to the first overlapping area S1 is defined as the first conductor density D1, and the ratio of the area of ​​the second conductor portion 32 to the second overlapping area S2 is defined as the second conductor density D2.

[0023] In this case, if the second conductor density D2 is lower than the first conductor density D1, the second conductor portion 32 in the transparent region 62 will be less dense than the first conductor portion 31 in the light-shielding region 61. When the second conductor portion 32 in the transparent region 62 is less dense, it becomes less conspicuous. Therefore, not only the first conductor portion 31 in the light-shielding region 61 but also the second conductor portion 32 becomes less conspicuous, improving the appearance of the planar antenna 101, and consequently improving the overall appearance of the window glass 201. Also, if the second conductor density D2 is lower than the first conductor density D1, the first conductor portion 31 in the light-shielding region 61 will be denser than the second conductor portion 32 in the transparent region 62. When the first conductor portion 31 is denser, the area of ​​the first conductor portion 31 is relatively well-secured, making it easier to ensure the antenna characteristics of the planar antenna 101. Therefore, we can provide a window glass 201 for vehicles that offers improved appearance and ensures antenna performance.

[0024] for example, D1 / D2 > 1.00 ···(1a) Satisfying these conditions allows for improved appearance and ensured antenna performance. In terms of improving appearance and ensuring antenna characteristics, D1 / D2 ≥ 1.03 ···(1b) This is preferable, D1 / D2 ≥ 1.40 ···(1c) More preferable, D1 / D2 ≥ 1.80 ···(1d) This is even more preferable. In terms of improving appearance, the upper limit of D1 / D2 is not particularly limited, but for example, it may be 5.00 or less, 4.00 or less, or 3.50 or less.

[0025] The second cutout portion 24 may be located in the second conductor portion 32 to improve appearance, but the first cutout portion 23 does not need to be located in the first conductor portion 31. Even if the first cutout portion 23 is not located in the first conductor portion 31, if the second conductor density D2 is lower than the first conductor density D1, it is possible to provide a vehicle window glass that improves appearance and ensures antenna characteristics.

[0026] Furthermore, the area of ​​the second cutout 24 is preferably larger than the area of ​​the first cutout 23 in terms of improving appearance. This makes the second conductor portion 32 in the transparent region 62 less conspicuous, improving the appearance of the planar antenna 101, and consequently improving the appearance of the window glass 201 as a whole. Depending on the external shape of the planar antenna 101 and the positional relationship of the boundary 66, it is preferable that the area of ​​the widest of the multiple voids 28 included in the second cutout 24 is larger than the area of ​​the widest of the multiple voids 27 included in the first cutout 23. This improves appearance. Furthermore, in terms of appearance, it is preferable that the area of ​​the narrowest of the multiple voids 28 included in the second cutout 24 is larger than the area of ​​the widest of the multiple voids 27 included in the first cutout 23.

[0027] In the example shown in Figure 1, the planar antenna 101 has a feed conductor section 7 having a feed point 5 and a ground conductor section 8 having a ground point 6. A signal line (not shown) is electrically connected to the feed point 5, and a ground wire (not shown) is electrically connected to the ground point 6. For example, the inner conductor (signal line) at one end of a coaxial cable is electrically connected to the feed point 5, and the outer conductor (ground wire) at the other end of the coaxial cable is electrically connected to the ground point 6. The other end of the coaxial cable is connected to, for example, a device that has one or both a transmitting function and a receiving function. The feed point 5 may also be equipped with a connector that can transmit and receive radio waves in a predetermined frequency band on the planar antenna 101, and connected to the device via the connector and coaxial cable.

[0028] In the example shown in Figure 1, the feed point 5 and the ground point 6 are included in the first conductor section 31. As a result, at least a portion of the feed conductor section 7 and at least a portion of the ground conductor section 8 overlap with the light-shielding region 61 in a plan view of the glass plate 65, making the feed conductor section 7 and the ground conductor section 8 less conspicuous. Therefore, the appearance of the planar antenna 101 is improved, and consequently, the appearance of the window glass 201 as a whole is also improved. Even if only one of the feed point 5 and the ground point 6 is included in the first conductor section 31, the conductor section including that one will overlap with the light-shielding region 61 in a plan view of the glass plate 65, thus improving the appearance.

[0029] In the example shown in Figure 1, the boundary 66 follows at least a portion of the outer edge 25 of the first cutout 23 and at least a portion of the outer edge 26 of the second cutout 24. As a result, multiple voids 27 and multiple voids 28 are arranged along the boundary 66, creating a uniform pattern with multiple voids neatly arranged, improving the appearance. In the example shown in Figure 1, the outer edge 25 is a line segment passing through the edges on the first direction side of the multiple voids 27 arranged in the second direction on the first direction side, and the outer edge 26 is a line segment passing through the edges on the third direction side of the multiple voids 28 arranged in the second direction on the third direction side. Note that even if the boundary 66 follows only one of at least a portion of the outer edge 25 and at least a portion of the outer edge 26, the cutout portion of the conductor 20 will follow the boundary 66, improving the appearance.

[0030] The first cutout portion 23 may include a plurality of holes 27 arranged along a direction substantially orthogonal to the boundary 66 (in the example shown in FIG. 1, the first direction or the third direction). Thereby, the plurality of holes 27 form a uniform pattern in which they are linearly and neatly arranged, improving the appearance. Similarly, the second cutout portion 24 may include a plurality of holes 28 arranged along a direction substantially orthogonal to the boundary 66 (in the example shown in FIG. 1, the first direction or the third direction). Thereby, the plurality of holes 28 form a uniform pattern in which they are linearly and neatly arranged, improving the appearance.

[0031] Let the total area of the plurality of holes 28 in the transmission region 62 be S V , and the area of the second conductor portion 32 be S C2 . At this time, S V / S C2 ≧1.0 ···(2a) If it satisfies, the enlargement of the second cutout portion 24 and the securing of the second conductor portion 32 can be achieved simultaneously, so it is preferable because it is possible to improve the appearance and secure the antenna characteristics. In terms of improving the appearance and securing the antenna characteristics, S V / S C2 ≧2.0 ···(2b) is more preferably satisfied, S V / S C2 ≧4.0 ···(2c) is even more preferable. In improving the appearance, the lower limit of S V / S C2 is not particularly limited, but for example, it may be 10.0 or less, or may be 6.0 or less.

[0032] If any of the formulas (2a), (2b), and (2c) is satisfied and the plurality of holes 28 in the transmission region 62 are arranged substantially uniformly, the appearance is particularly improved. If the plurality of holes 28 in the transmission region 62 are substantially the same size as each other, they are arranged substantially uniformly, so the appearance is particularly improved. Also, if the plurality of holes 28 in the transmission region 62 are arranged along a predetermined direction, they are arranged substantially uniformly, so the appearance is particularly improved.

[0033] Next, the planar antenna of the first embodiment will be described in more detail.

[0034] The planar antenna 101 shown in Figure 1 is a slot antenna having slots 10 formed in a flat conductor 20. Figure 1 is a plan view of the planar antenna 101 attached to a part of the main surface 60 of the glass plate 65, or the planar antenna 101, in plan view.

[0035] The planar antenna 101 comprises a flat conductor 20 in which slots 10 are formed. Slots 10 are elongated notches formed in the conductor 20.

[0036] The conductor 20 is an example of a flat conductor in the form of a film or plate, and in this example, it is a conductive film (a film having conductivity) whose overall shape is substantially rectangular. In the first embodiment, the conductor 20 has an outer edge 91 on the first direction side, an outer edge 92 on the second direction side, an outer edge 93 on the third direction side, and an outer edge 94 on the fourth direction side.

[0037] The conductor 20 has a flat first planar conductor 21 that extends to one side relative to the slot 10 and a flat second planar conductor 22 that extends to the other side relative to the slot 10. In this embodiment, the first planar conductor 21 and the second planar conductor 22 are separated by the slot 10. The conductor 20, including the first planar conductor 21 and the second planar conductor 22, may be directly attached to the main surface 60 of the glass plate 65, or it may be attached via the dielectric layer 120.

[0038] The planar antenna 101 may include a dielectric layer 120 on which a flat conductor 20, including a first planar conductor 21 and a second planar conductor 22, is formed. The conductor 20 may be a conductor formed by firing a paste containing a conductive metal (e.g., silver paste). For example, the planar antenna 101 may include a substrate (e.g., a flexible substrate) on which the flat conductor 20, including the first planar conductor 21 and the second planar conductor 22, is laminated on the dielectric layer 120. The dielectric layer 120 is preferably formed from a transparent resin such as polyimide or PET (polyethylene terephthalate), and the conductor 20 may be formed from copper or the like. By having such a laminated structure in the planar antenna 101, dimensional deviations of slots 10, etc., can be suppressed even if the conductor 20 is divided into a first planar conductor 21 and a second planar conductor 22. In addition, the planar antenna 101 can be easily attached to a mounting surface such as the main surface 60 of a glass plate 65.

[0039] The first planar conductor 21 has a feed point 5 to which a signal line (not shown) is electrically connected, and the second planar conductor 22 has a ground point 6 to which a grounding wire (not shown) is electrically connected. For example, the first planar conductor 21 is wider than the second planar conductor 22.

[0040] Slot 10 includes slots 11, 12, 13, and J-shaped slot 50. Slots 13, 11, 12, and J-shaped slot 50 are connected in this order.

[0041] Slot 11 is an example of a first slot, extending in a first direction between the power supply point 5 and the ground point 6.

[0042] Slot 12 is an example of a second slot, extending from the first-direction end 40 of slot 11 in a second direction different from the first direction.

[0043] Slot 13 is an example of a third slot. Slot 13 extends in a fourth direction from end 41 to an open end 42. End 41 is an example of the end of the first slot opposite to the first direction. Open end 42 is an example of an open end that opens in a fourth direction. Open end 42 opens at its outer edge 94 toward the fourth direction.

[0044] The J-shaped slot 50 extends in a J-shape from end 43 to open end 44. End 43 is an example of the end of the second slot in the second direction. Open end 44 is an example of an open end that opens in the first direction. The open end 44 opens at its outer edge 91 toward the first direction.

[0045] The slot width at the open end 44 of the J-shaped slot 50 is wider than the slot width at the second end 43 of the slot 12.

[0046] In this case, if the vehicle body is made of metal, and the radiating element of a wire antenna made of silver paste is placed close to the vehicle body on the window glass, the antenna's receiving gain tends to decrease due to interference with the metal.

[0047] However, since the planar antenna 101 according to this embodiment is a slot antenna, the electric field created by the current flowing through the conductor 20 is formed in a closed manner inside the conductor 20, and is therefore less susceptible to interference from metals or resins.

[0048] Therefore, the planar antenna 101 according to this embodiment can obtain stable characteristics even if metal objects such as a defogger or vehicle body are in close proximity to it, or even if resin parts of the vehicle body are in close proximity. Furthermore, even if a metal film such as a transparent conductive film is formed around it, it can similarly obtain characteristics that make it less susceptible to interference.

[0049] Communication frequencies vary from country to country, and even within a single country, different carriers use different frequency bands. Therefore, a broadband antenna capable of transmitting and receiving multiple communication waves is preferable.

[0050] The planar antenna 101 according to the first embodiment has a plurality of slots, such as slot 11, slot 12, slot 13, and J-shaped slot 50. In such a planar antenna 101 having a plurality of slots, the lower limit of the frequency of radio waves that can be transmitted and received is 450 M The frequency is preferably Hz, more preferably 500 MHz, and even more preferably 600 MHz or higher. The upper limit of the frequency of the radio waves that can be transmitted and received is preferably 7.5 GHz, more preferably 6.5 GHz, and even more preferably 6 GHz. The upper and lower limits can be appropriately combined depending on the communication standard used, but for example, it is preferable that the impedance is matched to be suitable for transmitting and receiving radio waves in the relatively high frequency band of the UHF (Ultra High Frequency) band and the 600 MHz to 6 GHz frequency band (sub6) used in fifth-generation communication (5G) standards, and the above frequency band is more preferably 450 MHz to 7.5 GHz.

[0051] The planar antenna 101 may be impedance-matched to efficiently transmit and receive Wi-Fi radio waves, which are part of a wireless LAN (Local Area Network). The planar antenna 101 may also be impedance-matched to transmit and receive radio waves in the frequency bands defined by the communication standards IEEE 802.11a, b, g, n, ac, ah, ax (863MHz~868MHz (Europe), 902MHz~928MHz (USA), 2400MHz~2497MHz (global), 5150MHz~5350MHz (global), 5470MHz~5850MHz (global), and even 5935MHz to 7125MHz, etc.).

[0052] The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency range of 2400MHz to 2483.5MHz used by Bluetooth®. The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency bands used for vehicle-to-infrastructure (V2I) or vehicle-to-vehicle (V2V) communication in Intelligent Transport Systems (ITS) (e.g., 755.5MHz to 764.5MHz as defined in ARIB STD-T109 (Japan), 5850MHz to 5925MHz as defined in IEEE802.11p). The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency bands used by other wireless communication technologies such as WiMAX® (e.g., 2300MHz to 2400MHz, 2496MHz to 2690MHz, 3400MHz to 3600MHz). The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the low band (3245MHz~4742MHz) of a UWB (ultra-wideband) wireless communication system.

[0053] Thus, according to the first embodiment, a wideband planar antenna capable of handling relatively high frequency bands up to about 6 GHz can be obtained, and a vehicle window glass equipped with the planar antenna can also be obtained.

[0054] In the planar antenna 101 shown in Figure 1, the J-shaped slot 50 has a curved contour. The curved contour of the J-shaped slot 50 allows the planar antenna 101 to transmit and receive signals across a wider frequency range.

[0055] The J-shaped slot 50 may have a portion where the slot width gradually increases. This allows the frequency range that the planar antenna 101 can transmit and receive to be broadened. As shown in Figure 1, the J-shaped slot 50 may have a portion that extends from the end 43 in the second direction of the slot 12 with a gradually increasing slot width, and then extends in the first direction while maintaining approximately the same slot width.

[0056] The J-shaped slot 50 may have a contour that is half the shape of an ellipse with a major axis substantially parallel to the second direction. This results in a smooth curve in the contour of the J-shaped slot 50, which allows the frequency range that the planar antenna 101 can transmit and receive to be broadened. The planar antenna 101 shown in Figure 1 is an example in which the slot width gradually increases until the extension direction of the J-shaped slot 50 is toward the first direction, and the slot width becomes substantially the same in the portion extending parallel to the first direction.

[0057] Furthermore, the J-shaped slot may be a slot bent into a J-shape, or it may be formed so that a straight line bends into a J-shape. As a result, the J-shaped slot includes multiple line segment slots whose direction of extension and length differ in at least one of them, making it easier to adjust the frequency for impedance matching.

[0058] The J-shaped slot may have a portion that extends in the first direction while maintaining approximately the same slot width. In the example shown in Figure 1, the slot extends in the first direction while maintaining approximately the same slot width. However, the J-shaped slot may have a portion that extends in the first direction while gradually increasing or decreasing the slot width. For example, the J-shaped slot may extend in the first direction toward the open end 44 while gradually increasing or decreasing the slot width.

[0059] In the example shown in Figure 1, slot 13 has a wider slot width than slot 11. This facilitates impedance matching in the frequency band between 600 MHz and 6 GHz. However, the slot width of slot 13 may be the same as or shorter than the slot width of slot 11.

[0060] As shown in Figure 1, it is preferable that the slot length of slot 12 is shorter than the slot length of slot 11. This makes impedance matching easier in the high frequency band of 2.69 GHz to 6 GHz.

[0061] In the example shown in Figure 1, the outer edge 94 where the open end 42 of the slot 13 is located has a portion that passes through the open end 42 of the slot 13 and is parallel to a virtual line 94a that is perpendicular to the extension direction of the slot 13. However, the outer edge 94 may also have a portion that is inclined with respect to the virtual line 94a.

[0062] In the planar antenna 101 shown in Figure 1, the outer edge 93 facing the outer edge 91 includes a curved portion 93a. The inclusion of the curved portion 93a in the outer edge 93 facilitates impedance matching in the frequency band of 750 MHz to 1 GHz. Furthermore, the amount of the first planar conductor 21 used can be reduced, improving productivity. In the first embodiment, the curved portion 93a, which is the end of the outer edge 93, has a contour that is one-quarter of an ellipse with a major axis substantially parallel to the second direction, but it may have other curved contours such as a circle or a contour that is one-quarter or less of an ellipse.

[0063] In the planar antenna 101 shown in Figure 1, the first planar conductor 21 and the second planar conductor 22 are formed in a grid-like shape, having perforated sections (cutout sections containing multiple voids) in which a part of the conductor 20 is hollowed out. In the planar antenna 101 shown in Figure 1, cutout sections are formed in the first planar conductor 21 and the second planar conductor 22.

[0064] In this example, the first planar conductor 21 includes a first cutout portion 23 that overlaps with the light-shielding region 61 and a first portion of the second cutout portion 24 that overlaps with the light-transmitting region 62 (in the example shown in Figure 1, this is the portion on the second direction side with respect to the open end 44). On the other hand, the second planar conductor 22 includes a second portion of the second cutout portion 24 that overlaps with the light-transmitting region 62 (in the example shown in Figure 1, this is the portion on the fourth direction side with respect to the open end 44).

[0065] In a configuration where the conductor 20 is mounted on the glass plate 65 by printing, if the metal area of ​​the conductor 20 is too large, the difference in heat absorption between glass and metal may reduce the moldability of the glass. By forming a cutout, the area of ​​the conductor 20 can be increased while ensuring the moldability of the glass. A larger area of ​​the conductor 20 improves the design flexibility of the slot antenna.

[0066] In this embodiment, in the region where the power supply conductor section 7 and the grounding conductor section 8 are not provided, the first planar conductor 21 has a grid-like cutout, and the second planar conductor 22 also has a grid-like cutout. The shape of each cutout (void) in the cutout is not limited to a square, but may be a polygon other than a square (for example, a triangle and a hexagon), a circle, or other shape.

[0067] Figure 2 is an enlarged view showing a portion of the vehicle window glass of the second embodiment in a plan view. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. The planar antenna 102 of the window glass 202 of the second embodiment differs from the first embodiment in that the D1 / D2 value is smaller than that of the first embodiment. This improves the appearance.

[0068] Figure 3 is an enlarged view showing a portion of the vehicle window glass of the third embodiment in plan view. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. The planar antenna 103 of the window glass 203 of the third embodiment differs from that of the first embodiment in that the shape of the void 28 has the second direction as the longitudinal direction. This further improves the appearance.

[0069] In the example shown in Figure 3, multiple voids 28 are arranged in the first direction. The vertical lines (conductor portions extending in the first direction) in the second conductor portion 32 have been removed. The absence of vertical lines results in a cleaner appearance and improved aesthetics.

[0070] Figure 4 is an enlarged view showing a part of the vehicle window glass of the fourth embodiment in plan view. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. The planar antenna 104 of the window glass 204 of the fourth embodiment differs from the first embodiment in that the second cutout portion 24 contains only a single void 28 within a closed loop region enclosed by the boundary 66 and the outer edge of the planar antenna 104. This improves the appearance. The planar antenna 104 also differs from the first embodiment in that the first cutout portion 23 contains only a single void 27 within a closed loop region enclosed by the boundary 66 and the outer edge of the planar antenna 104.

[0071] In the example shown in Figure 4, the first portion of the second cutout 24 (in this example, the portion on the second direction side with respect to the open end 44) ​​contains only a single void 28 within a closed loop region enclosed by the boundary 66 and the outer edge of the second conductor portion 32. Similarly, the second portion of the second cutout 24 (in this example, the portion on the fourth direction side with respect to the open end 44) ​​contains only a single void 28 within a closed loop region enclosed by the boundary 66 and the outer edge of the second conductor portion 32. The first cutout 23 contains only a single void 27 within a closed loop region enclosed by the boundary 66 and the outer edge of the first conductor portion 31.

[0072] Figure 5 is an enlarged view showing a part of the vehicle window glass of the fifth embodiment in plan view. A description of the same configuration and effects as in the above-described embodiments will be omitted by referring to the above description. The planar antenna 105 of the window glass 205 of the fifth embodiment differs from the fourth embodiment in that the shape of the first cutout portion 23 is the same as that of the first embodiment. As a result, the appearance is further improved, and it is easier to secure the area of ​​the conductor portion in the conductor 20 compared to the fourth embodiment, thus making it easier to secure antenna characteristics.

[0073] Next, we will describe the measured VSWR, which is one of the antenna characteristics of the planar antennas in each embodiment.

[0074] Figures 6 to 10 show examples of measured VSWR results for planar antennas of the first to fifth embodiments, respectively. Figure 11 shows an example of simulation results for another planar antenna based on the first embodiment, with different dimensions for the first conductor section 31, the first cutout section 23, the second conductor section 32, and the second cutout section 24. VSWR represents the voltage standing wave ratio. A VSWR of 3.5 or less is preferable, and a value closer to 1 indicates better impedance matching. Note that in the 600MHz to 6GHz range, the VSWR standard (3.5 or less) is just an example, and there may be frequency bands where the VSWR exceeds 3.5, but it is preferable that the frequency band exceeding the predetermined VSWR is narrow.

[0075] In the case of the planar antenna 101 (Figure 1), as shown in Figure 6, the VSWR is 3.5 or less in the 600MHz to 6GHz band, resulting in impedance matching up to a relatively high frequency band of about 6GHz. In the case of another planar antenna 101 (Figure 17), as shown in Figure 11, the VSWR exceeds 3.5 from around 1.0GHz to around 1.4GHz and from around 5.0GHz to around 5.4GHz, but is 3.5 or less in other frequency bands. Therefore, impedance matching is achieved up to a relatively high frequency band of about 6GHz, excluding the ranges from around 1.0GHz to around 1.4GHz and from around 5.0GHz to around 5.4GHz. Thus, it is sufficient if the frequency bands from around 1.0GHz to around 1.4GHz and from around 5.0GHz to around 5.4GHz are unused.

[0076] In the case of the planar antenna 102 (Figure 2), as shown in Figure 7, impedance matching was achieved up to a relatively high frequency band of about 6 GHz, similar to the case of the planar antenna 101 (Figure 1).

[0077] In the case of the planar antenna 103 (Figure 3), as shown in Figure 8, the VSWR exceeds 3.5 around 2.5 GHz, but is 3.5 or less in other frequency bands. Therefore, impedance matching was obtained up to a relatively high frequency band of about 6 GHz, except around 2.5 GHz. Thus, it is sufficient if the frequency band around 2.5 GHz is not used.

[0078] In the case of the planar antenna 104 (Figure 4), as shown in Figure 9, the VSWR exceeds 3.5 below 1.0 GHz, but is 3.5 or less in the frequency band above 1.0 GHz. Therefore, impedance matching was obtained up to a relatively high frequency band of about 6 GHz, excluding below 1.0 GHz. Thus, it is sufficient if the frequency band below 1.0 GHz is not used.

[0079] In the case of the planar antenna 105 (Figure 5), as shown in Figure 10, impedance matching was achieved up to a relatively high frequency band of about 6 GHz, similar to the case of the planar antenna 101 (Figure 1).

[0080] In each measurement or simulation shown in Figures 6 to 11, the dimensions common to each planar antenna were set to the values ​​shown in Figure 12 (in mm). The dimensions unique to each planar antenna were set to the values ​​shown in Figures 12 to 17 (in mm). In Figure 17, the line width (including the outermost edge) is 0.1 mm. In each measurement, the planar antenna was placed on the upper passenger side of the vehicle's windshield, and the shortest distance between the planar antenna and the flange (the metal window frame that secures the window glass) was set to 20 mm.

[0081] Figure 18 is a table showing the VSWR values ​​under various conditions during actual measurement or simulation. In Figure 18, #1 to #6 correspond, respectively, to planar antennas 101 to 105 and 101 (another planar antenna in the first embodiment). #0 corresponds to the case where planar antenna 101 is a solid planar conductor without any cutouts. #* represents any of #1 to #6. S C2 This represents the area of ​​the second conductor section 32. C1This represents the area of ​​the first conductor section 31. V This represents the total area of ​​the multiple voids 28 in the permeable region 62.

[0082] In all cases from #1 to #6, satisfying the above equation "D1 / D2 > 1.00" yielded good impedance matching results as shown in Figures 6 to 11.

[0083] Figure 19 shows an example of the measured antenna gain of the planar antenna of the second embodiment (Figure 2). Figure 20 shows an example of the measured antenna gain of the planar antenna of the fifth embodiment (Figure 5). The antenna gain shown on the vertical axis in Figures 19 and 20 represents the average value of the measured antenna gain at each azimuth angle from 0° to 358° in the horizontal plane (elevation angle 0°). The dimensions used for the measurements in Figures 19 and 20 were also set to the values ​​shown in Figures 12, 13, and 16. Good results were obtained for antenna gain, one of the antenna characteristics, up to a relatively high frequency band of about 6 GHz.

[0084] Although embodiments have been described above, the technology of this disclosure is not limited to the embodiments described above. Various modifications and improvements are possible, such as combinations or substitutions with some or all of the other embodiments.

[0085] For example, a planar antenna placed on a glass plate may be part of or all of the multiple antennas included in a diversity antenna or a MIMO (Multiple-Input and Multiple-Output) antenna. This improves communication quality. [Explanation of symbols]

[0086] 5. Power supply point 6 Grounding point 7 Power supply conductor section 8. Grounding conductor section 10-17 slots 20 Conductors 21 First Planar Conductor 22 Second Planar Conductor 23. First cutout section 24. Second cutout section 25,26 Outer edge 27,28 Cavities 31 First Conductor Section 32 Second Conductor Section 40, 41, 43 Ends 42,44 open end 50 J-shaped slots 60 Main surface 61 Shading area 62 Transparent area 63 Boundary area 64 Outer edge 65 Glass plate 66 Boundary 67 Flange end 91, 92, 93, 94 Outer edge 93a Curved section 94a Virtual Line 101-105 Planar antenna 120 Dielectric layer 130 Light blocking layer 201-205 Windowpanes

[0087] Furthermore, the entire contents of the specifications, claims, drawings, and abstracts of Japanese Patent Application No. 2021-214751, filed on December 28, 2021, and Japanese Patent Application No. 2022-178312, filed on November 7, 2022, are incorporated herein by reference as disclosures of the present invention.

Claims

1. The antenna comprises a glass plate, a light-shielding layer formed on the glass plate, and a planar antenna in which a cutout portion containing at least one void is formed within a planar conductor. In a plan view of the glass plate, when the region having the light-shielding layer is defined as the light-shielding region and the region not having the light-shielding layer is defined as the light-transmitting region, The planar antenna is arranged to straddle the boundary between the light-shielding region and the light-transmitting region, and has a first conductor portion that overlaps with the light-shielding region and a second conductor portion that overlaps with the light-transmitting region. When the area in which the planar antenna overlaps with the light-shielding region is defined as the first overlapping area, the area in which the planar antenna overlaps with the light-transmitting region is defined as the second overlapping area, the ratio of the area of ​​the first conductor portion to the first overlapping area is defined as the first conductor density, and the ratio of the area of ​​the second conductor portion to the second overlapping area is defined as the second conductor density, The second conductor density is lower than the first conductor density. The cutout portion has a first cutout portion formed in the first conductor portion and a second cutout portion formed in the second conductor portion. The area of ​​the second cutout is larger than the area of ​​the first cutout. The first hollowed-out portion and the second hollowed-out portion each include a plurality of voids, A vehicle window glass in which the area of ​​the largest of the multiple voids included in the second cutout is larger than the area of ​​the largest of the multiple voids included in the first cutout.

2. The vehicle window glass according to claim 1, wherein the area of ​​the narrowest of the multiple voids included in the second cutout is larger than the area of ​​the widest of the multiple voids included in the first cutout.

3. The planar antenna includes a feed conductor portion having a feed point and a ground conductor portion having a ground point. The vehicle window glass according to claim 1, wherein at least one of the power supply point and the grounding point is included in the first conductor portion.

4. The vehicle window glass according to claim 1, wherein the boundary is along at least a portion of the outer edge of the cutout portion.

5. The vehicle window glass according to claim 1, wherein the cutout portion includes a plurality of voids arranged along the boundary.

6. The vehicle window glass according to claim 1, wherein the cutout portion includes a plurality of voids arranged along a direction substantially perpendicular to the boundary.

7. The total area of ​​the voids in the transparent region is S Ｖ The area of ​​the second conductor portion is S Ｃ２ In that case, S Ｖ / S Ｃ２ ≧1.0 A vehicle window glass according to claim 1 that satisfies the following conditions.

8. The window glass for a vehicle according to claim 7, wherein the voids in the transparent region are arranged substantially uniformly.

9. The vehicle window glass according to claim 4, wherein the cutout portion located in the transparent region contains only a single void within a closed-loop region enclosed by the boundary and the outer edge of the planar antenna.

10. The first conductor density is D １ , the second conductor density is D ２ In that case, D １ / D ２ A vehicle window glass according to claim 1, satisfying ≥ 1.

03.

11. The vehicle window glass according to claim 1, wherein the planar antenna is capable of transmitting and receiving radio waves of 600 MHz or higher.

12. The vehicle window glass according to claim 11, wherein the planar antenna is capable of transmitting and receiving radio waves of 6 GHz or less.

13. The vehicle window glass according to claim 1, wherein a plurality of the planar antennas are arranged on a single glass plate.

14. The vehicle window glass according to any one of claims 1 to 13, wherein the glass plate is for use as a windshield, side glass, rear glass, or roof glass.

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