JP7365458B2 - Window glass for vehicles and glass antenna for DAB - Google Patents

Description

The present invention relates to a vehicle window glass and a DAB glass antenna.

BACKGROUND OF THE INVENTION A defogger for removing dew condensation or icing, an antenna for receiving predetermined radio waves, and the like are sometimes provided on the surface of a vehicle window glass (particularly a rear glass) attached to an automobile. For example, Patent Document 1 proposes a vehicle window glass that includes a defogger and a glass antenna for receiving DAB (Digital Audio Broadcasting; hereinafter referred to as "DAB") broadcasts.

Re-published patent number 2012/153664

2. Description of the Related Art Techniques for improving the reception performance of glass antennas have been developed.

In particular, in order to receive vertically polarized DAB broadcasts with high sensitivity, a glass antenna having a certain length in the vertical direction is provided. On the other hand, when a defogger is provided together with a glass antenna, the range in which the glass antenna can be placed becomes narrower by the area occupied by the defogger. Therefore, the length in the vertical direction in which the glass antenna can be arranged is limited, and it has been difficult to provide a glass antenna that can receive vertically polarized DAB broadcasts with high sensitivity.

Furthermore, in vehicle models such as hatchback-type vehicles in which the mounting angle of the rear glass is close to vertical or relatively large, the glass area of the rear glass is relatively small. Therefore, when installing a defogger and a glass antenna on the rear glass, the range in which the glass antenna can be placed is extremely limited, and it is difficult to install a glass antenna that can receive DAB broadcasts with high sensitivity. Ta.

One aspect of the present invention has been made in view of the above circumstances, and an object thereof is to provide a technique that can improve the reception performance of DAB broadcasts.

The present invention adopts the following configuration in order to solve the above-mentioned problems.

That is, a vehicle window glass according to one aspect of the present invention includes a glass plate and a DAB glass antenna formed on either surface of the glass plate, and the DAB glass antenna is connected to the glass plate. It has a power feeding part disposed on the lower side of the plate and a first element extending in the vertical direction.

Generally speaking, it is said that installing an antenna at a high place is more advantageous because the antenna is less affected by obstacles when it is installed at a high place than when it is installed at a low place. Therefore, the glass antenna for DAB has conventionally been placed on the upper side of the window glass. On the other hand, as a result of our earnest efforts, the inventors of the present invention have found that arranging the DAB glass antenna on the lower side of the window glass improves the sensitivity of the DAB glass antenna than arranging it on the upper side of the glass plate. I found out that it gets better. Therefore, in this configuration, by arranging the power feeding part of the DAB glass antenna on the lower side of the glass plate, the DAB glass antenna is arranged on the lower side of the window glass. Therefore, according to this configuration, by arranging the DAB glass antenna on the lower side of the window glass, the receiving performance of DAB broadcasting can be improved.

In addition, when an amplifier is provided between the power feeding section and the receiver, this amplifier is generally placed on the lower side of the window glass. Therefore, if the power supply part is placed on the top side of the window glass, it may be necessary to partially cut out the vehicle frame for the wiring extending from the power supply part to the amplifier. If cut out, the strength of the vehicle body will be reduced. On the other hand, according to the above configuration, since the power feeding section is arranged on the lower side of the window glass, the above possibility can be eliminated. Furthermore, the distance between the amplifier and the power feeding section can be shortened, and the reception performance of the DAB glass antenna can be improved.

Moreover, as another form of the window glass according to the one aspect, the first element may extend vertically upward from the power feeding section. According to this configuration, since the first element is directly connected to the power feeding section, the overall size of the DAB glass antenna can be made compact.

Further, as another form of the window glass according to the above one aspect, the window glass includes a pair of opposing bus bar parts and a plurality of hot wire parts each extending in the horizontal direction and arranged in the vertical direction, and the window glass has a pair of bus bar parts facing each other, and a plurality of hot wire parts each extending in the horizontal direction and arranged in the vertical direction. The defogger may further include a plurality of hot wire portions, each of which is connected to each of the pair of busbar portions. The defogger may be arranged above the DAB glass antenna, and the DAB glass antenna may further include a second element extending in the horizontal direction and connected to the first element. According to this configuration, since the defogger is provided, the range in which the DAB glass antenna can be installed is limited on the surface of the glass plate. Therefore, in this configuration, by providing the second element extending in the horizontal direction in the DAB glass antenna, it is possible to suppress the vertical length of the DAB glass antenna while maintaining the DAB broadcast reception performance. Therefore, according to the configuration, a DAB glass antenna with guaranteed reception performance can be provided on a window glass provided with a defogger.

Moreover, as another form of the window glass according to the one aspect, the defogger may further include one or more vertical striations extending in the vertical direction so as to intersect each of the plurality of hot wire parts. The inventors of the present invention have discovered that the sensitivity of a glass antenna for DAB can be improved by providing a vertical linear portion on the defogger. Therefore, according to the configuration, by providing the defogger with one or more vertical striations, the DAB broadcast reception performance can be improved.

Moreover, as another form of the window glass according to the one aspect, the defogger may be arranged so that standing waves are not generated in the defogger by radio waves in the DAB frequency band. The inventors of the present invention have found that depending on the arrangement of the vertical linear portions, standing waves of radio waves in the DAB frequency band are generated in the defogger, and the sensitivity of the DAB glass antenna is reduced. Therefore, according to the configuration, it is possible to prevent the sensitivity of the DAB glass antenna from decreasing and improve the reception performance of DAB broadcasts.

Moreover, as another form of the window glass according to the one aspect, the defogger may be disposed vertically upwardly by 46 mm or more from the upper end of the DAB glass antenna. The inventors have discovered that when a DAB glass antenna is brought closer to a distance of less than 46 mm from a defogger (especially when there is no vertical striation), the sensitivity of the DAB glass antenna decreases due to interference from the defogger. I found it. Therefore, in this configuration, by arranging the defogger so as to be vertically upwardly separated by 46 mm or more from the upper end of the DAB glass antenna, the DAB glass antenna is separated from the defogger by 46 mm or more. Therefore, according to the configuration, by separating the DAB glass antenna from the defogger by 46 mm or more, the DAB broadcast reception performance can be improved.

Moreover, as another form of the window glass according to the one aspect, the first element of the DAB glass antenna may have a vertical length of 20 mm or more. Generally, in order to receive vertically polarized DAB broadcasts, it is desirable to use an antenna with a long vertical length. However, there are cases where the range in which the glass antenna is provided is limited, such as by providing a defogger, and in such a case, there is a possibility that the length of the DAB glass antenna in the vertical direction cannot be formed to a desired length. On the other hand, the inventors of the present invention have found that if the length of the DAB glass antenna in the vertical direction is 20 mm or more, the DAB broadcast reception performance can be maintained. Therefore, with this configuration, the DAB broadcast reception performance can be maintained while reducing the vertical length of the DAB glass antenna.

In addition, as another form of the window glass according to the above one aspect, the vehicle window glass is such that parallel light is applied to the window glass from the horizontal direction, and the projected area of the window glass thereby generated is 0.5 m ² . Therefore, the window glass may be attached to the window frame of the vehicle such that the attachment angle of the window glass is 45 degrees or more and 75 degrees or less when the horizontal direction is a reference. In such a window with a narrow mounting area, the range in which the DAB glass antenna can be installed is limited. In particular, when a DAB glass antenna is provided together with a defogger, the range in which the DAB glass antenna can be installed is limited. However, according to the present invention, the sensitivity of the DAB glass antenna can be increased, so that it can be installed even in windows with such a narrow installation area. In other words, the present invention is particularly effective in such windows with a narrow installation area. Note that a window glass having such a mounting area and mounting angle is, for example, a rear glass of a hatchback type automobile. Here, the rear glass is generally curved. When the window glass is curved, the mounting angle varies at each point on the window glass. In the above configuration, the curved window glass is attached so that the attachment angle at any point on the window glass is 45 degrees or more and 75 degrees or less, when the horizontal direction is 0 degrees.

Further, a DAB glass antenna according to one aspect of the present invention is a DAB glass antenna formed on either side of a glass plate used as a window glass for a vehicle, and arranged on the lower side of the glass plate. and a linear first element extending in the vertical direction. As described above, with this configuration, the reception performance of DAB broadcasting can be improved.

According to the present invention, the reception performance of DAB broadcasting can be improved.

FIG. 1 schematically illustrates a window glass according to an embodiment. FIG. 2 schematically shows an example of how the window glass according to the embodiment is used. FIG. 3A schematically illustrates a window glass according to another form. FIG. 3B schematically illustrates a window glass according to another form. FIG. 3C schematically illustrates a window glass according to another form. FIG. 3D schematically illustrates a window glass according to another form. FIG. 4 schematically illustrates a window glass according to another form. FIG. 5A schematically illustrates an embodiment in which a DAB glass antenna is provided on the lower side of the glass plate. FIG. 5B schematically illustrates a comparative example in which a DAB glass antenna is provided on the upper side of the glass plate. FIG. 6A shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB. FIG. 6B shows the average value of the sensitivity (gain) of each example in the band 3 of DAB. FIG. 7A shows the measurement results of sensitivity (gain) of each comparative example for each frequency of band 3 of DAB. FIG. 7B shows the average value of the sensitivity (gain) of each comparative example in the DAB band 3 band. FIG. 8 schematically illustrates an example in which an L-shaped DAB glass antenna is provided on the lower side of the glass plate. FIG. 9A shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB. FIG. 9B shows the average value of sensitivity (gain) of each example in the band 3 of DAB. FIG. 10 schematically illustrates an example in which a defogger is provided on a glass plate with an L-shaped DAB glass antenna provided on the lower side. FIG. 11A shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB. FIG. 11B shows the average value of the sensitivity (gain) of each example in the band 3 of DAB. FIG. 12 schematically illustrates an embodiment in which a defogger is provided with a vertical line portion. FIG. 13A shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB. FIG. 13B shows the average value of the sensitivity (gain) of each example in the band 3 of DAB. FIG. 14 schematically illustrates an example in which a DAB glass antenna is provided on the lower side of a glass plate provided with a defogger having five vertical striations, with the lengths of vertical elements and horizontal elements adjusted respectively. do. FIG. 15A shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB. FIG. 15B shows the average value of sensitivity (gain) of each example in the band 3 of DAB. FIG. 16 schematically illustrates a reference example in which an L-shaped DAB glass antenna is provided on the upper side of the glass plate. FIG. 17A shows the measurement results of sensitivity (gain) of each reference example for each frequency of band 3 of DAB. FIG. 17B shows the average value of the sensitivity (gain) of each reference example in the band 3 of DAB. FIG. 18 schematically illustrates an embodiment in which a defogger is provided on a glass plate with an L-shaped DAB glass antenna provided on the upper side. FIG. 19A shows the measurement results of the sensitivity (gain) of each reference example for each frequency of band 3 of DAB. FIG. 19B shows the average value of sensitivity (gain) of each reference example in the band 3 of DAB. FIG. 20 schematically illustrates a reference example in which a defogger is provided with a vertical linear portion. FIG. 21A shows the measurement results of the sensitivity (gain) of each reference example for each frequency of band 3 of DAB. FIG. 21B shows the average value of the sensitivity (gain) of each reference example in the band 3 of DAB. FIG. 22 schematically illustrates a reference example in which a defogger is provided with a vertical linear portion. FIG. 23A shows a simulation result of current distribution when a 170 MHz radio wave is received in a reference example in which one vertical linear portion is provided. FIG. 23B shows a simulation result of current distribution when a 240 MHz radio wave is received in a reference example in which one vertical linear portion is provided. FIG. 24A shows a simulation result of current distribution when a 170 MHz radio wave is received in a reference example in which three vertical linear portions are provided. FIG. 24B shows a simulation result of current distribution when a 240 MHz radio wave is received in a reference example in which three vertical linear portions are provided. FIG. 25 shows simulation results of the sensitivity (gain) of each reference example for each frequency of band 3 of DAB. FIG. 26 schematically illustrates an embodiment in which the power feeding section is provided closer to the side. FIG. 27 shows the measurement results of sensitivity (gain) of each example with respect to each frequency of band 3 of DAB.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment (hereinafter also referred to as "this embodiment") according to one aspect of the present invention will be described below based on the drawings. However, this embodiment described below is merely an illustration of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the invention. That is, in implementing the present invention, specific configurations depending on the embodiments may be adopted as appropriate.

§1 Configuration example <Window glass>
First, a window glass 1 according to the present embodiment will be explained using FIG. 1. FIG. 1 is a plan view schematically illustrating a window glass 1 according to this embodiment. Note that FIG. 1 schematically illustrates the window glass 1 seen from the inside of the vehicle. That is, the back side of the paper in FIG. 1 is the outside of the vehicle, and the front side of the paper in FIG. 1 is the inside of the vehicle. Hereinafter, for convenience of explanation, the vertical direction in FIG. 1 will be referred to as "up and down," the right direction in FIG. 1 will be referred to as "left," and the left direction in FIG. 1 will be referred to as "right." Note that the horizontal direction in FIG. 1 corresponds to the "horizontal direction" of the present invention, and the vertical direction in FIG. 1 corresponds to the "vertical direction" of the present invention. Here, the vertical direction refers to, for example, a direction perpendicular to the ground when the window glass 1 is attached to the vehicle body. Further, the horizontal direction refers to, for example, a direction parallel to the ground when the window glass 1 is attached to the vehicle body. Note that when the surface is inclined, the vertical direction and the horizontal direction include approximate directions having components in each direction.

The window glass 1 according to this embodiment is a vehicle window glass that is attached to an automobile, and specifically is a rear glass of the automobile. However, the type of window glass of the present invention is not limited to the rear glass, and can be appropriately selected depending on the embodiment. As illustrated in FIG. 1, a window glass 1 according to the present embodiment includes a substantially trapezoidal glass plate 2, and is attached to a window frame provided at the rear of an automobile.

As illustrated in FIG. 1, a DAB glass antenna 4 for receiving DAB broadcasting is provided on the lower side of the glass plate 2, and above the DAB glass antenna 4. , an anti-fog defogger 3 having a predetermined pattern is provided. The defogger 3 and the DAB glass antenna 4 may be provided on either the inside surface or the outside surface of the glass plate 2. Each of these components will be explained below.

<Glass plate>
First, the glass plate 2 will be explained. As illustrated in FIG. 1, the glass plate 2 according to the present embodiment includes an upper side portion 21 extending in the left-right direction, a lower side portion 22 facing the upper side portion 21 on the lower side, and the upper side portion 21 and the lower side portion 22. , and a right side 24 that connects the right ends of the upper side 21 and the lower side 22.

The glass plate 2 according to this embodiment is used as a window glass for an automobile, and is configured in a shape that corresponds to the window frame of the automobile to which it is attached. The type of automobile to which the glass plate 2 is attached may be appropriately selected depending on the embodiment, and may be a hatchback type, for example. For example, the glass plate 2 may be used as a rear window of a hatchback type automobile. Moreover, the glass plate 2 may be formed into a curved shape. For example, the glass plate 2 may be formed in a curved shape from the periphery to the center so that the surface on the inside of the vehicle is concave and the surface on the outside of the vehicle is convex.

Such a glass plate 2 can have various configurations depending on the embodiment. Further, as the glass plate 2, a known glass plate for automobiles can be used. For example, the glass plate 2 may be made of heat-absorbing glass, general clear glass or green glass, or UV green glass. However, such glass plate 2 can be adjusted so that its solar absorption rate, visible light transmittance, etc. satisfy safety standards. An example of the composition of clear glass and an example of the composition of heat ray absorbing glass are shown below.

(clear glass)
SiO ₂ :70-73% by mass
Al ₂ O ₃ :0.6-2.4% by mass
CaO: 7-12% by mass
MgO: 1.0 to 4.5% by mass
R ₂ O: 13 to 15% by mass (R is an alkali metal)
Total iron oxide (T-Fe ₂ O ₃ ) converted to Fe ₂ O ₃ : 0.08 to 0.14% by mass

(heat ray absorbing glass)
The composition of the heat ray absorbing glass is, for example, based on the composition of clear glass, the ratio of total iron oxide (T-Fe ₂ O ₃ ) converted to Fe ₂ O ₃ is 0.4 to 1.3% by mass, and CeO The ratio of TiO ₂ is 0 to 2% by mass, the ratio of TiO ₂ is 0 to 0.5% by mass, and the glass framework components (mainly SiO ₂ and Al ₂ O ₃ ) are replaced with T-Fe ₂ O ₃ and CeO ₂ and TiO ₂ can be reduced by the increment of TiO 2 .

Note that the type of glass plate 2 is not limited to clear glass, heat ray absorbing glass, etc., and can be appropriately selected depending on the embodiment. For example, the glass plate 2 may be a resin window made of acrylic, polycarbonate, or the like.

<Defogger>
Next, the anti-fogging defogger 3 will be explained. As illustrated in FIG. 1, the defogger 3 according to the present embodiment is provided on the upper side 21 side of the glass plate 2 so as to be disposed above the DAB glass antenna 4, which will be described later. It has a predetermined pattern to remove ice.

Specifically, the defogger 3 includes a pair of busbar portions 31 that face each other in the left-right direction, and a plurality of (six in FIG. 1) hot wire portions 32 that extend in the left-right direction and are arranged in the vertical direction. . Both ends of each hot wire section 32 are connected to each bus bar section 31, respectively. Each bus bar section 31 is provided with a connection section 34 for attaching a predetermined connection terminal.

A predetermined connection terminal is attached to this connection portion 34 by soldering or the like, and a wiring (not shown) from a power source of the automobile is connected to the bus bar portion 31 via the connection terminal. Therefore, the driver of the car can supply electricity to the defogger 3 by operating an operation panel (not shown).

When electricity is supplied to the defogger 3, a current is generated in each hot wire section 32 via the bus bar section 31. Then, each hot wire portion 32 is heated by the flowing electric energy, and the glass plate 2 is heated at the portion where each hot wire portion 32 is formed. Thereby, dew condensation and freezing on the surface of the glass plate 2 can be removed.

Further, the defogger 3 according to the present embodiment is provided with a plurality of (five in FIG. 1) vertical linear portions 33 that extend in the vertical direction so as to intersect each heating wire portion 32. The defogger 3 is made of an electrically conductive material. Therefore, when this defogger 3 is close to a DAB glass antenna 4, which will be described later, the defogger 3 may affect the reception performance of the DAB glass antenna 4.

Here, as shown in each experiment (particularly Experiment 4 and Experiment 8) to be described later, the reception performance of the DAB glass antenna 4 is improved by short-circuiting each hot wire section 32 by each vertical line section 33. be able to. Therefore, in this embodiment, the defogger 3 is provided with a plurality of vertical linear portions 33 to improve the reception performance of the DAB glass antenna 4. In the example of FIG. 1, one vertical filament 33 is arranged at the center of the glass plate 2 in the left-right direction, and two vertical filaments are arranged in the left-right direction around this one vertical filament 33. The portions 33 are arranged symmetrically. Thereby, the defogger 3 according to this embodiment is formed symmetrically.

Note that the shape, number, and arrangement of the bus bar section 31, the shape, number, and arrangement of the hot wire section 32, the shape, number, and arrangement of the vertical striation section 33, and the position of the connection section 34 are not limited to these examples. It can be designed as appropriate depending on the embodiment. For example, the vertical filament 33 may be a single piece or may be omitted. However, as shown in Experiment 9, which will be described later, the present inventors discovered that depending on the arrangement of the vertical striations 33, standing waves are generated in the defogger 3 due to radio waves in the DAB frequency band, and the DAB glass antenna 4 It was found that the sensitivity of Therefore, it is preferable that the vertical striations 33 be arranged so that standing waves of radio waves in the DAB frequency band do not occur in the defogger 3. This prevents the sensitivity of the DAB glass antenna 4 from decreasing and improves the reception performance of DAB broadcasts.

Specifically, the arrangement of the vertical linear portions 33 such that standing waves of DAB radio waves are not generated is as follows. That is, in each hot wire portion 32, the distance P (hereinafter, this distance is When the pitch (which may also be referred to as "pitch") is an integral multiple of the half wavelength of the received radio wave, a standing wave of the radio wave may occur in each part. Therefore, by arranging each vertical linear part 33 so that the distance P of each part is not equal to an integral multiple of F shown in Equation 1 below, standing waves due to radio waves in the DAB frequency band are not generated in the defogger 3. You can do it like this.

Note that F indicates a half wavelength of DAB radio waves. λ ₀ indicates the wavelength of the DAB radio wave on the hot wire section 32. K indicates the wavelength shortening rate on the hot wire portion 32. The value of this K (wavelength shortening rate) can be specified based on the physical properties (relative dielectric constant) of the glass, the thickness of the glass, the frequency of the radio waves to be received, and the like. For common glasses, the value of K is set in the range of 0.6 to 0.8. Further, c indicates the speed of light. f indicates the frequency of DAB radio waves.

Assuming that DAB band 3 is assumed, 170 MHz to 240 MHz is substituted for f in Equation 1 above. Also, if we substitute 3.0×10 ⁸ (m/s) for the speed of light c and 0.7 for the wavelength shortening rate K, then F will be a value in the range of 0.44 m to 0.62 m. Become. Therefore, the distance P between the portion sandwiched between the bus bar portion 31 and the vertical striation portion 33 and the portion sandwiched between the adjacent vertical striation portions 33 ranges from 0.44 m to 0.62 m. (and an integral multiple of this), it is possible to prevent standing waves from occurring in the defogger 3 due to band 3 radio waves. Note that the above calculation was performed using simple numerical values for convenience of explanation. In determining the value F that should be avoided by the distance P of each part, the values of K, f, and c are not limited to the above values, and may be appropriately selected according to the embodiment.

The defogger 3 is formed by laminating a conductive material on the surface of the glass plate 2 in a predetermined pattern. The material of the defogger 3 only needs to have conductivity, and can be selected as appropriate for the embodiment. Examples of the material of the defogger 3 include silver, gold, platinum, and the like. This defogger 3 can be formed, for example, by printing a conductive silver paste containing silver powder, glass frit, etc. on the surface of the glass plate 2 and firing it.

<Glass antenna for DAB>
Next, the DAB glass antenna 4 for receiving DAB broadcasting will be explained. DAB is a digital radio broadcasting standard adopted in Europe and other countries. DAB mainly uses a band 3 having a frequency band of 174 MHz to 240 MHz and an L band having a frequency band of 1452 MHz to 1492 MHz. The DAB glass antenna 4 may be configured as appropriate depending on the frequency band to be received. Note that each frequency band may be slightly changed depending on the specifications of the automobile. Therefore, for example, the band 3 from 174 MHz to 240 MHz may be treated as a band from 170 MHz to 240 MHz. In this specification, for convenience of explanation, a band from 170 MHz to 240 MHz is also used as the DAB band 3 frequency band.

The DAB glass antenna 4 according to the present embodiment includes a rectangular power feeding part 41 arranged on the lower side 22 side of the glass plate 2, and a linear vertical element 42 extending vertically upward from the power feeding part 41. A linear horizontal element 43 is connected to the vertical element 42 and extends in the left direction (horizontal direction). As illustrated in FIG. 1, the horizontal element 43 is connected to the upper end of the vertical element 42 at its right end. Thereby, the vertical element 42 and the horizontal element 43 constitute an L-shaped antenna. Of this L-shaped antenna, the vertical element 42 corresponds to the "first element" of the present invention, and the horizontal element 43 corresponds to the "second element" of the present invention.

As mentioned above, the conventional glass antenna for DAB is arranged on the upper side of the window glass. On the other hand, the present inventors found that placing the DAB glass antenna on the bottom side of the window glass was better than placing it on the top side of the glass plate, based on various experiments (especially Experiment 1) described below. It has been found that the sensitivity of the glass antenna for DAB is improved. Therefore, in this embodiment, the power feeding part 41 of the DAB glass antenna 4 is placed on the lower side 22 side of the glass plate 2, so that the DAB glass antenna 4 is placed on the lower side of the window glass 1. Thereby, the DAB broadcast reception performance of the DAB glass antenna 4 can be improved.

Here, the length of the vertical element 42 in the vertical direction (vertical direction) and the length of the horizontal element 43 in the horizontal direction (horizontal direction) may be set as appropriate depending on the frequency band to be received. Generally, in order to receive a vertically polarized signal such as DAB, it is better to make the vertical length of the vertical element 42 as long as possible.

However, in this embodiment, since the defogger 3 is provided above the DAB glass antenna 4, the range in which the DAB glass antenna 4 can be installed is limited. In other words, the vertical length of the vertical element 42 that can be formed is limited by the length of the defogger 3 in the vertical direction.

Therefore, in this embodiment, in order to ensure the length of the DAB glass antenna 4, a horizontal element 43 connected to the vertical element 42 is provided. Thereby, in this embodiment, the length of the vertical element 42 in the vertical direction can be suppressed while maintaining the reception performance of the DAB glass antenna 4.

However, if the vertical element 42 is extremely short, the reception performance of the DAB glass antenna 4 will be significantly reduced. Therefore, based on the experiments described below (particularly Experiment 2, Experiment 5, and Experiment 6), it is desirable that the vertical length of the vertical element 42 be 20 mm or more. Further, it is desirable that the total length of the vertical element 42 and the horizontal element 43 be configured to be equal to 1/2 wavelength of the radio wave to be received.

Further, as illustrated in FIG. 1, the DAB glass antenna 4 according to the present embodiment is arranged such that the upper end of the DAB glass antenna 4 is separated downward from the defogger 3 by a distance D1. In other words, the defogger 3 is arranged at a distance D1 vertically upward from the upper end of the DAB glass antenna 4. In this embodiment, since the horizontal element 43 is connected to the upper end of the vertical element 42, the upper end of the vertical element 42 and the upper side of the horizontal element 43 correspond to the upper end of the glass antenna 4.

The distance D1 may be set as appropriate depending on the embodiment. However, if the distance D1 is too short, the defogger 3 made of a conductive material may have an adverse effect on the reception performance of the DAB glass antenna 4. Therefore, based on the experiments described below (especially Experiment 3), in order to prevent the defogger 3 from affecting the reception performance of the DAB glass antenna 4, it is desirable to set the distance D1 to 46 mm or more. . Note that if the distance D1 is too long, the range in which the DAB glass antenna 4 can be installed becomes narrow, and the length of the vertical element 42 in the vertical direction is greatly restricted. Therefore, the upper limit value of the distance D1 may be set as appropriate depending on the length of the vertical element 42 in the vertical direction.

Note that the DAB glass antenna 4 according to this embodiment is configured as a so-called dipole antenna. That is, the DAB glass antenna 4 further includes a rectangular ground connection part 44 disposed near the power feeding part 41, and a filamentous ground line part extending leftward (horizontally) from this ground connection part 44. It is equipped with 45.

The inner conductor of a coaxial cable (not shown) connected to a receiver (not shown) mounted on the vehicle is electrically connected to the power feeding section 41 and receives signals received by the vertical element 42 and the horizontal element 43. receive. On the other hand, the outer conductor of the coaxial cable is electrically connected to the ground connection part 44 and grounded. An amplifier (not shown) may be provided between the power feeding section 41 and the receiver. As a result, DAB broadcasts can be received by a receiver installed in a car. Note that when an amplifier is provided between the power feeding section 41 and the receiver, this amplifier is placed on the lower side 22 side of the window glass 1. Thereby, the amplifier and the power feeding section 41 can be connected by wiring without cutting out the frame of the vehicle body. Furthermore, the distance between the amplifier and the power feeding section 41 can be shortened, thereby suppressing loss in wiring and improving the reception performance of the DAB glass antenna 4.

However, the configuration of the DAB glass antenna 4 is not limited to this example, and the DAB glass antenna 4 may be configured as a so-called monopole antenna by omitting the ground connection part 44 and the ground wire part 45. may be done. In this case, the outer conductor of the coaxial cable may be grounded, for example, by being directly connected to the body of the automobile.

Similar to the defogger 3, the DAB glass antenna 4 can be formed by laminating conductive materials on the surface of the glass plate 2 in a predetermined pattern. The material of the DAB glass antenna 4 only needs to have conductivity, and can be selected as appropriate for the embodiment. Examples of materials for the DAB glass antenna 4 include silver, gold, platinum, and the like. This DAB glass antenna 4 can be formed, for example, by printing a conductive silver paste containing silver powder, glass frit, etc. on the surface of the glass plate 2 and firing it.

<Manufacturing method>
Next, a method for manufacturing the window glass 1 according to this embodiment will be explained. The glass plate 2 of the window glass 1 according to the present embodiment can be formed by a press forming method in which the glass plate 2 is formed by pressing, a self-weight bending method in which the glass plate 2 is bent by its own weight, or the like.

Here, when forming the glass plate 2 in each method, the glass plate 2 is heated in a heating furnace to around its softening point. Before being carried into the heating furnace, the glass plate 2 is formed into a flat plate, and a conductive silver paste containing silver powder, glass frit, etc. is printed on the surface of the glass plate 2. Then, by carrying the glass plate 2 into a heating furnace, the glass plate 2 is molded, and the silver paste printed on the glass plate 2 is fired to form the defogger 3 and the DAB glass antenna 4. can.

<Usage example>
Next, an example of use of the window glass 1 according to this embodiment will be explained using FIG. 2. FIG. 2 schematically shows an example of how the window glass 1 according to this embodiment is used. As illustrated in FIG. 2, the window glass 1 according to this embodiment can be used as a rear glass of a hatchback type vehicle 8.

This vehicle 8 is equipped with a window frame 9 on the rear side, and the window glass 1 is attached to this window frame 9. For example, window glass 1 is illuminated with parallel light from the horizontal direction, the resulting projected area is 0.5 m ² , and the installation angle is 45 m when the horizontal direction is the reference (when the horizontal direction is 0 degrees). It is attached to the window frame 9 so that the angle is greater than or equal to 75 degrees. Note that when the window glass 1 is curved, the mounting angle varies at each point on the window glass 1. In this case, the window glass 1 is attached to the window frame 9 such that the attachment angle at any point on the window glass 1 is greater than or equal to 45 degrees and less than or equal to 75 degrees. Further, the projected area can be measured, for example, as follows. That is, the window glass 1 is attached to the window frame of a vehicle, and parallel light parallel to the ground is irradiated onto the window glass 1 from inside the vehicle. Then, the transmitted light of the window glass 1 is projected onto a screen outside the vehicle installed perpendicular to the ground, and the area of the shadow of the window glass 1 projected onto this screen is measured. Thereby, the projected area of the window glass 1 can be measured.

When the window glass 1 is attached to the window frame 9 having such an attachment area and attachment angle, the size of the window glass 1 becomes relatively small. Therefore, if the defogger 3 is provided on the window glass 1 together with the DAB glass antenna 4, the range in which the DAB glass antenna 4 can be installed will be limited. However, as described above, according to this embodiment, the length of the vertical element 42 in the vertical direction can be suppressed while maintaining the receiving performance of the DAB glass antenna 4. That is, even if the range in which the DAB glass antenna 4 can be installed is limited, it is possible to maintain the receiving performance of the DAB glass antenna 4. Therefore, this embodiment is particularly effective for windows with such a mounting area and mounting angle.

§2 Modifications Although the embodiments of the present invention have been described in detail above, the above descriptions are merely illustrative of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the invention. Regarding each component of the window glass 1, glass plate 2, defogger 3, and DAB glass antenna 4, components may be omitted, replaced, or added as appropriate depending on the embodiment. For example, the following changes are possible. In addition, below, the same code|symbol is used regarding the same component as the said embodiment, and description was abbreviate|omitted suitably.

(Glass plate)
For example, regarding the above-described specific configuration of the glass plate 2, components may be omitted, changed, replaced, or added as appropriate depending on the embodiment. The glass plate 2 may have a shape that is curved toward the front, or may have a flat shape, for example. Further, the glass plate 2 may be used for purposes other than rear glass.

Further, the glass plate 2 is composed of one glass plate. However, the glass plate 2 may be composed of a laminated glass in which an outer glass plate and an inner glass plate are bonded to each other via an interlayer film. Furthermore, the glass plate 2 is formed into a trapezoidal shape. However, the shape of the glass plate 2 does not need to be limited to such a shape, and may be appropriately selected depending on the embodiment.

(Glass antenna for defogger and DAB)
Further, for example, regarding the specific configurations of each of the defogger 3 and the DAB glass antenna 4, components may be omitted, changed, replaced, or added as appropriate depending on the embodiment.

For example, the defogger 3 does not have to be formed symmetrically. Further, in the embodiment described above, a plurality of (five in the figure) vertical linear portions 33 are arranged symmetrically. However, the plurality of vertical striations 33 do not have to be arranged symmetrically in this way. Further, in the embodiment described above, five vertical linear portions 33 are provided. However, the number of vertical striations 33 is not limited to five, and may be one to four, or six or more. That is, the arrangement and number of vertical striations 33 may be appropriately selected depending on the embodiment. However, so that the pitch between adjacent vertical line portions 33 and the pitch between the bus bar portion 31 and the vertical line portion 33 adjacent to the bus bar portion 31 are not equal to an integral multiple of F shown in Equation 1 above, It is preferable to select the arrangement and number of vertical striations 33. Further, the vertical arrangement interval of the hot wire portions 32 may or may not be constant. Furthermore, the shapes of the power supply section 41 and the ground connection section 44 do not need to be limited to rectangular shapes, and may be appropriately selected depending on the embodiment.

Further, for example, in the DAB glass antenna 4, the positions where the vertical element 42 and the horizontal element 43 are connected are not limited to the above example, and may be appropriately selected depending on the embodiment. . For example, the horizontal element 43 may be connected to any position of the vertical element 42 in the center. This allows a T-shaped or cross-shaped antenna to be constructed.

Furthermore, the window glasses 1A to 1C illustrated in FIGS. 3A and 3B may be configured. FIG. 3A schematically illustrates a window glass 1A in which the defogger 3 is omitted from the window glass 1 described above. FIG. 3B schematically illustrates a window glass 1B in which the vertical striation portion 33 is omitted from the window glass 1.

First, the window glass 1A illustrated in FIG. 3A will be described. As illustrated in FIG. 3A, the defogger 3 may be omitted. In this case, the defogger 3 no longer limits the installation range of the DAB glass antenna. Therefore, as illustrated in FIG. 3A, the horizontal element 43 may be omitted from the DAB glass antenna 4, and the antenna may be configured with the vertical element 42. A DAB glass antenna 4A illustrated in FIG. 3A is similar to the DAB glass antenna 4 described above, except that the horizontal element 43 is omitted.

Next, the window glass 1B illustrated in FIG. 3B will be described. As illustrated in FIG. 3B, the vertical linear portion 33 in the defogger 3 may be omitted. The defogger 3B illustrated in FIG. 3B is the same as the defogger 3 described above except that the vertical linear portion 33 is omitted. In this case, the effect of improving the reception performance of the DAB glass antenna 4 due to the vertical striations 33 cannot be expected. Therefore, in this case, it is desirable that the distance D1 is set to 46 mm or more so that the defogger 3B does not adversely affect the receiving performance of the DAB glass antenna 4.

Further, for example, in the embodiment described above, the power feeding section 41 is arranged at the center in the horizontal direction, and the vertical element 42 is directly connected to the power feeding section 41. However, the arrangement of the power feeding section 41 and the shape of each element of the DAB glass antenna 4 do not need to be limited to such an example, and may be changed as appropriate depending on the embodiment. The power feeding unit 41 may be arranged closer to the left side portion 23 or closer to the right side portion 24. Furthermore, the vertical element 42 does not need to be directly connected to the power supply section 41. As an example, the modifications shown in FIGS. 3C and 3D are possible.

FIG. 3C schematically illustrates a window glass 1D in which a DAB glass antenna 4D is provided near the right side portion 24. The DAB glass antenna 4D includes a power feeding portion 41D disposed near the right side portion 24, and a wiring portion 46D extending from the power feeding portion 41D toward the left side portion 23. The wiring portion 46D includes, in order from the power feeding portion 41D side, a first portion 461D extending slightly upward from the power feeding portion 41D, a second portion 462D extending to the left from the upper end of the first portion 461D, and a second portion 462D extending slightly from the left end of the second portion 462D. It is composed of a third portion 463D extending downward, and a fourth portion 464D extending largely to the left from the lower end of the third portion 463D.

In this modification, the vertical element 42D is connected to the left end of the fourth portion 464D of the wiring portion 46D, and extends vertically upward from the left end of the fourth portion 464D. Further, the horizontal element 43D is connected to the upper end of the vertical element 42D and extends to the right from the upper end of the vertical element 42D. This horizontal element 43D is shorter in the left-right direction than the fourth portion 464D of the wiring portion 46D.

Moreover, a ground connection part 44D is arranged on the left side of the power supply part 41D. In this modification, as shown in FIG. 3C, the first part 461D to the third part 463D of the wiring part 46D are arranged to surround the upper side of the ground connection part 44D, so that An extending linear portion 47D is provided. The ground filament portion 45D extends horizontally from the lower end of the filament portion 47D.

In addition, the window glass 1D has the same configuration as the window glass 1 described above. Note that the wiring portion 46D may be formed of the same material as each element (42D, 43D). Therefore, all or part of the wiring section 46D may be configured to perform the same function as each element (42D, 43D).

Moreover, FIG. 3D schematically illustrates a window glass 1E having a DAB glass antenna 4E having a different shape from the DAB glass antenna 4D shown in FIG. 3C. The DAB glass antenna 4E includes a power feeding section 41E disposed near the right side portion 24, and a grounding connection section 44E disposed on the right side of the power feeding section 41E.

A wiring section 46E extends horizontally from the power supply section 41E. The vertical element 42E is connected to the left end of the wiring section 46E and extends vertically upward from the left end of the wiring section 46E. Further, the horizontal element 43E is connected to the upper end of the vertical element 42E and extends to the right from the upper end of the vertical element 42E. This horizontal element 43E is shorter in the left-right direction than the wiring portion 46E. Similar to the above modification, this wiring portion 46E may be formed of the same material as each element (42E, 43E). Therefore, all or part of this wiring section 46E may be configured to perform the same function as each element (42E, 43E).

On the other hand, a filament portion 47E extends slightly downward from the ground connection portion 44E. The ground wire portion 45E extends horizontally from the lower end of the wire portion 47E. This ground wire portion 45E extends to the left side portion 23 side from the vertical element 42E. In addition, the window glass 1E has the same configuration as the window glass 1 described above.

As described above, the arrangement of the power feeding section 41 and the shape of each element of the DAB glass antenna 4 can be changed as appropriate depending on the embodiment.

<Others>
Further, as described above, by providing the vertical linear portion 33 on the defogger 3, it is possible to improve the reception performance of the DAB glass antenna 4. Therefore, when improving the receiving performance of the DAB glass antenna 4 by providing the vertical striation 33 on the defogger 3, the DAB glass antenna 4 is placed on the upper side 21 side of the glass plate 2. It's okay. This example will be explained below using FIG. 4.

FIG. 4 schematically illustrates a window glass 1C in which a DAB glass antenna 5 is provided on the upper side 21 side of the glass plate 2. The DAB glass antenna 5 illustrated in FIG. 4 is the same as the DAB glass antenna 4 described above, except that it is disposed on the upper side 21 side of the glass plate 2.

That is, the DAB glass antenna 5 includes a rectangular power feeding part 51 disposed on the upper side 21 side of the glass plate 2, a linear vertical element 52 extending vertically downward from the power feeding part 51, and a vertical element 52. A linear horizontal element 53 is connected to and extends in the left direction (horizontal direction). Further, the DAB glass antenna 5 is configured as a dipole antenna, and includes a rectangular ground connection part 54 arranged near the power feeding part 51 and a rectangular ground connection part 54 extending leftward (horizontally) from this ground connection part 54. A ground filament portion 55 is provided.

Furthermore, the defogger 3C illustrated in FIG. 4 is the same as the defogger 3 described above except that it is disposed on the lower side 22 side of the glass plate 2. Here, the distance D2 between the lower end of the DAB glass antenna 5 and the defogger 3C may be set as appropriate depending on the embodiment. Based on each experiment (especially Experiment 7) described later, the distance D2 may be set to 85 mm or more. Note that in this modification, the horizontal element 53 is connected to the lower end of the vertical element 52. Therefore, the lower end of the vertical element 52 and the lower side of the horizontal element 53 correspond to the lower end of the DAB glass antenna 5.

Examples of the present invention will be described below. However, the present invention is not limited to this example. In order to examine the reception performance of the DAB glass antenna of the present invention, the following experiments 1 to 9 were conducted. Each experiment will be explained below.

(1) Experiment 1: Arrangement of glass antenna for DAB First, in this experiment 1, as illustrated in FIGS. 5A and 5B, the glass antenna for DAB was arranged on the upper side or lower side of the glass plate. We investigated the influence of this on the reception performance of a glass antenna for DAB. FIG. 5A schematically illustrates Example 1 in which the DAB glass antenna 4C is arranged on the lower side 22 side of the glass plate 2. Moreover, FIG. 5B schematically illustrates Comparative Example 1 in which the DAB glass antenna 5 is arranged on the upper side 21 side of the glass plate 2.

As illustrated in FIG. 5A, a window glass of Example 1 having the same configuration as the modified window glass 1A illustrated in FIG. 3A was prepared. Specifically, a curved rear glass of a hatchback type wagon was prepared as the window glass according to Example 1. The prepared window glass according to Example 1 was then attached to the rear window frame of a hatchback type wagon. The length of the upper side of the window frame to which the glass plate 2 was attached was 920 mm, the length of the lower side of the window frame was 1100 mm, and the vertical height of the window frame was 415 mm. A glass plate 2 was formed by a known manufacturing process to match the size of this window frame. In addition, the power supply part 41, the ground connection part 44, and the ground wire part 45 are arranged 5 mm above the lower side of the window frame, and the power supply part 41 and the vertical element 42 are arranged in the center of the glass plate 2 in the left-right direction. The window glass according to Example 1 was obtained by configuring the DAB glass antenna 4A. The power supply section 41 and the ground connection section 44 according to Example 1 each had a rectangular shape of 20 mm x 20 mm. Further, the length of the vertical element 42 in the vertical direction was 300 mm. Furthermore, the length of the ground wire portion 45 in the left-right direction was 110 mm.

Furthermore, as illustrated in FIG. 5A, window glasses according to Examples 2 to 5 were obtained by moving the DAB glass antenna 4A of Example 1 toward the right side portion 24 at a pitch of 100 mm. That is, the window glass according to Example 2 was obtained by horizontally moving the DAB glass antenna 4A of Example 1 toward the right side portion 24 by 100 mm. Similarly, window glasses according to Examples 3, 4, and 5 were obtained by horizontally moving the DAB glass antenna 4A of Example 1 by 200 mm, 300 mm, and 400 mm toward the right side portion 24, respectively. In each of the DAB glass antennas 4A according to Examples 2 to 4, the length of the vertical element 42 in the vertical direction was 300 mm, as in Example 1. On the other hand, the vertical length of the vertical element 42 of the DAB glass antenna 4A according to Example 5 was 290 mm. In the window glass according to Example 5, the distance from the right side portion 24 of the glass plate 2 to the vertical element 42 was 141.5 mm.

On the other hand, as illustrated in FIG. 5B, a window glass of Comparative Example 1 was prepared by arranging the DAB glass antenna 4A of Example 1 on the upper side 21 side of the glass plate 2. Specifically, a glass plate 2 was formed in the same manner as in Example 1 above. In addition, the power supply part 51, the ground connection part 54, and the ground wire part 55 are arranged 5 mm below the top edge of the window frame, and the power supply part 51 and the vertical element 52 are arranged in the center of the glass plate 2 in the left-right direction. By configuring the DAB glass antenna 5, a window glass according to Comparative Example 1 was obtained. The power supply section 51 and the ground connection section 54 according to Comparative Example 1 each had a rectangular shape of 20 mm x 20 mm, as in Example 1. Further, the vertical length of the vertical element 52 was 310 mm. Furthermore, the length of the ground wire portion 55 in the left-right direction was 110 mm.

Further, as illustrated in FIG. 5B, window glasses according to Comparative Examples 2 to 5 were obtained by moving the DAB glass antenna 5 of Comparative Example 1 toward the right side portion 24 at a pitch of 100 mm. That is, the window glass according to Comparative Example 2 was obtained by horizontally moving the DAB glass antenna 5 of Comparative Example 1 by 100 mm toward the right side portion 24 side. Similarly, window glasses according to Comparative Examples 3, 4, and 5 were obtained by horizontally moving the DAB glass antenna 5 of Comparative Example 1 by 200 mm, 300 mm, and 400 mm toward the right side portion 24, respectively. Note that the length in the vertical direction of each of the vertical elements 52 of the DAB glass antennas 5 according to Comparative Examples 2 to 4 was 300 mm. On the other hand, the vertical length of the vertical element 52 of the DAB glass antenna 5 according to Comparative Example 5 was 290 mm. In the window glass according to Comparative Example 2, the distance from the right side portion 24 of the glass plate 2 to the vertical element 52 was 60.5 mm.

The window glasses of Examples 1 to 5 and Comparative Examples 1 to 5 thus obtained were attached to a hatchback type wagon as described above. Then, the DAB band 3 radio waves are radiated to the wagon in the anechoic chamber, and each DAB glass antenna receives the DAB band 3 signal, thereby increasing the sensitivity of each DAB glass antenna. It was measured. A network analyzer (manufactured by Agilent, model: E-5071C) was used to measure the sensitivity of each DAB glass antenna. The specific conditions for measurement are as follows.
・Glass plate installation angle: 62 degrees tilted at the bottom point in the vertical direction, 54 degrees tilted at the center point in the vertical direction, 45 degrees tilted at the top point in the vertical direction ・Angular resolution: Angle Measurement by rotating the wagon 360 degrees every 3 degrees Frequency resolution: Measurement every 1 MHz in the range of 174 MHz to 240 MHz Elevation angle between radio wave transmission position and antenna: 1.7 degrees (0 degrees from the ground and horizontal direction) , the zenith direction is 90 degrees)
Note that the above conditions are the same in Experiments 2 to 8 below unless otherwise specified. The sensitivity of each DAB glass antenna was defined by relative gain (dBd) with respect to a half-wavelength dipole antenna. No amplifier was installed between the receiver and each DAB glass antenna, and a through cable was used. Figures 6A, 6B, 7A and 7B show the results.

FIG. 6A shows the measurement results of sensitivity (gain) of each of Examples 1 to 5 for each frequency of DAB band 3. Further, FIG. 6B shows the average value of the sensitivity (gain) of each of Examples 1 to 5 in the DAB band 3. On the other hand, FIG. 7A shows the measurement results of Comparative Examples 1 to 5 for each frequency of DAB band 3. Further, FIG. 7B shows the average value of the sensitivity (gain) of each of Comparative Examples 1 to 5 in the DAB band 3.

Comparing the average value of sensitivity of each Example 1 to 5 (FIG. 6B) and the average value of sensitivity of each Comparative Example 1 to 5 (FIG. 7B), each Example 1 to 5 is different from each Comparative Example 1 to 5. The sensitivity was about 1 dBd better. That is, it has been found that the reception performance of DAB broadcasts (particularly band 3) is better when the DAB glass antenna is placed on the bottom side of the window glass rather than on the top side.

Note that, referring to the measurement results, among Examples 1 to 5, Example 3 had the best reception performance. Furthermore, among Comparative Examples 1 to 5, Comparative Example 3 had the best reception performance. This is presumed to be due to the fact that each of the ground wire portions (45, 55) extends to the left. That is, by shifting the DAB glass antenna from the horizontal center of the glass plate in the opposite direction to the direction in which the ground wire extends by the length of the ground wire, the receiving performance of the DAB glass antenna can be improved. I found out that it is possible.

(2) Experiment 2: Length of vertical element and horizontal element Next, in this experiment 2, as illustrated in FIG. The effect of changing the length on the receiving performance of the DAB glass antenna was investigated. FIG. 8 schematically illustrates window glasses according to Examples 7 to 11 constituting the L-shaped antenna in Experiment 2.

First, by setting the length L1 of the vertical element 42 in Example 1 of Experiment 1 to 240 mm, and setting the horizontal length of the ground wire portion 45 to 300 mm, an implementation having the same configuration as Example 1 was performed. A window glass according to Example 6 was obtained. That is, in the DAB glass antenna 4 according to the sixth embodiment, the length L2 of the horizontal element 43 is 0 mm. Note that the wiring connected to the ground connection part 44 was grounded at a position 150 mm from the terminal of the connection part provided on the vehicle body side.

Then, by shortening the length L1 of the vertical element 42 of Example 6 and increasing the length L2 of the horizontal element 43, window glasses of Examples 7 to 11 were obtained. In the DAB glass antenna 4 according to Example 7, the length L1 of the vertical element 42 was 100 mm, and the length L2 of the horizontal element 43 was 120 mm. Further, in the DAB glass antenna 4 according to Example 8, the length L1 of the vertical element 42 was 80 mm, and the length L2 of the horizontal element 43 was 140 mm. Further, in the DAB glass antenna 4 according to Example 9, the length L1 of the vertical element 42 was 60 mm, and the length L2 of the horizontal element 43 was 160 mm. Further, in the DAB glass antenna 4 according to Example 10, the length L1 of the vertical element 42 was 40 mm, and the length L2 of the horizontal element 43 was 180 mm. Further, in the DAB glass antenna 4 according to Example 11, the length L1 of the vertical element 42 was 20 mm, and the length L2 of the horizontal element 43 was 190 mm. That is, in Examples 7 to 11, the vertical element 42 and the horizontal element 43 constituted an L-shaped antenna. For each of Examples 6 to 11, the sensitivity of each DAB glass antenna was measured in the same manner as in Experiment 1 above. Figures 9A and 9B show the results.

FIG. 9A shows the measurement results of sensitivity (gain) of each of Examples 6 to 11 with respect to each frequency of band 3 of DAB. Further, FIG. 9B shows the average value of the sensitivity (gain) of each of Examples 6 to 11 in the DAB band 3. As shown in FIGS. 9A and 9B, it was found that the reception performance of the DAB glass antenna decreased as the length L1 of the vertical element was shortened. As shown in FIG. 9B, the average sensitivity of the DAB glass antenna according to Example 11 was −8.4 dBd. It is presumed that if the sensitivity is lower than this, it will affect the reception of DAB broadcasts. That is, from these results, it was found that by setting the length of the vertical element to 20 mm or more, it is possible to ensure reception performance that can withstand receiving DAB (particularly band 3) broadcasting.

(3) Experiment 3: Distance between the defogger and the glass antenna for DAB Next, in this experiment 3, as illustrated in FIG. The influence of changing the distance D1 on the reception performance of the DAB glass antenna was investigated. FIG. 10 schematically illustrates a windowpane according to Example 14 in which two hot wire portions 32 are provided in Experiment 3.

First, by setting the length L2 of the horizontal element 43 in Example 7 of Experiment 2 to 120 mm, a window glass according to Example 12A having the same configuration as Example 7 was obtained. That is, the window glass according to Example 12A has the same configuration as the window glass according to Example 7 except for the length of the horizontal element 43 of the DAB glass antenna 4. Furthermore, a window glass according to Example 12B was obtained by setting the length L1 of the vertical element 42 of Example 12A to 80 mm and setting the length L2 of the horizontal element 43 to 140 mm.

Further, by setting the length L2 of the horizontal element 43 of Example 12A to 140 mm and providing the defogger 3B having one hot wire portion 32 to the window glass according to Example 12, the window glass according to Example 13 can be Obtained. In the window glass according to Example 13, the distance D1 between the defogger 3B and the DAB glass antenna 4 was 241 mm. Further, the length between the busbar portions 31 of the defogger 3B was 900 mm near the top end and 970 mm near the bottom end. Met. Then, as illustrated in FIG. 10, by increasing the hot wire portions 32 of the defogger 3B according to Example 13 downward at a pitch of 32.5 mm, window glasses according to Examples 14 to 20 are obtained. Ta. That is, in each of the window glasses according to Examples 14 to 20, a defogger 3B having 2 to 8 hot wire portions 32 is formed, and the distance D1 between the defogger 3B and the DAB glass antenna 4 is 208.5 mm and 176 mm, respectively. , 143.5mm, 111mm, 78.5mm, 46mm and 13.5mm. For each of Examples 12A, 12B, and 13 to 20, the sensitivity of each DAB glass antenna was measured in the same manner as in each experiment described above. Figures 11A and 11B show the results. Note that "Example 12" in FIG. 11A indicates the average value of the measured values obtained for Example 12A and Example 12B.

FIG. 11A shows the measurement results of sensitivity (gain) of Examples 12 to 20 for each frequency of DAB band 3. Further, FIG. 11B shows the average value of the sensitivity (gain) of each of Examples 13 to 20 in the DAB band 3. As shown in FIGS. 11A and 11B, the reception performance of the DAB glass antenna did not change significantly between Examples 12 to 19, but deteriorated in Example 20. That is, it has been found that when the defogger is brought closer to a distance of less than 46 mm from the DAB glass antenna, the sensitivity of the DAB glass antenna decreases due to interference from the defogger. Therefore, it has been found that by setting the distance D1 between the defogger and the DAB glass antenna to be 46 mm or more, it is possible to prevent the defogger from affecting the reception performance of the DAB glass antenna. In particular, if the defogger is not provided with a vertical striation, it is possible to prevent the reception performance of the DAB glass antenna from deteriorating by setting the distance D1 between the defogger and the DAB glass antenna to 46 mm or more. I understand.

(4) Experiment 4: Vertical Line Section Next, in this Experiment 4, as illustrated in FIG. 12, the effect of providing a vertical line section on the reception performance of the DAB glass antenna was investigated. FIG. 12 schematically illustrates a window glass according to Example 23 in which five vertical striations 33 are provided.

First, a window glass according to Example 6 of Experiment 2 was prepared, in which a defogger was not provided and a linear antenna was configured. Further, in Example 12A of Experiment 3, where a defogger is not provided and an L-shaped antenna is configured, the length L1 of the vertical element 42 is 100 mm, and the length L2 of the horizontal element 43 is 140 mm. A window glass according to Example 12C was prepared. Furthermore, one hot wire section 32 was added to the lowest part of the defogger 3B of Example 20 of Experiment 3, in which a defogger was provided but no vertical striations were provided, bringing the total number of hot wire sections 32 to nine. I made it into a book. Then, the window glass according to Example 20A was prepared by shifting the defogger 3B upward so that the distance between the lowest heating wire part 32 and the DAB glass antenna 4 was 13.5 mm.

Then, as illustrated in FIG. 12, window glasses according to Examples 21 to 23 were obtained by providing the defogger 3B according to Example 20A with vertical striations 33. In the window glass according to Example 21, the vertical striation 33 was provided only in the center in the left-right direction. That is, in the window glass according to Example 21, a total of one vertical striation 33 was provided.

In addition, in the window glass according to Example 22, one vertical striation 33 is provided at the center in the left-right direction, and one vertical striation is formed in each of the left and right directions around the one vertical striation 33. 33 were arranged symmetrically. That is, in the window glass according to Example 22, a total of three vertical striations 33 were provided. In addition, the distance W1 between each vertical line part 33 arranged in the left-right direction and the vertical line part 33 arranged in the center was 200 mm.

Furthermore, in the window glass according to Example 23, one vertical striation 33 is provided at the center in the left-right direction, and two vertical striations are provided in the left-right direction around the one vertical striation 33. 33 were arranged symmetrically. That is, in the window glass according to Example 22, a total of five vertical striations 33 were provided. In addition, the distance W1 between each vertical line part 33 arranged on the inside in the left-right direction and the vertical line part 33 arranged in the center was 200 mm. Further, the distance W2 between each vertical striation 33 disposed on the outside in the left-right direction and the vertical striation 33 disposed in the center was 300 mm. For each of Examples 6, 12C, 20A, and 21 to 23, the sensitivity of each DAB glass antenna was measured in the same manner as in each experiment described above. Figures 13A and 13B show the results.

FIG. 13A shows the measurement results of sensitivity (gain) of Examples 6, 12C, 20A, and 21 to 23 for each frequency of DAB band 3. Further, FIG. 13B shows the average value of the sensitivity (gain) of each of Examples 6, 12C, 20A, and 21 to 23 in the DAB band 3. As shown in FIGS. 13A and 13B, Examples 22 and 23 in which a plurality of vertical linear portions were provided had almost the same reception performance as Example 6 in which a defogger was not provided. In particular, when comparing Examples 21 to 23, there was a tendency for the reception performance of the DAB glass antenna to improve as the number of vertical striations increased.

Here, Examples 22 and 23 are similar to the defogger in Example 20 of Experiment 3 above, with a plurality of vertical striations added. That is, in Examples 22 and 23, the reception performance of the DAB glass antenna was improved, even though the defogger was placed in a range where the reception performance of the DAB glass antenna deteriorated in Experiment 3 above. Therefore, from this experiment 4, even if the defogger is placed in a range that deteriorates the receiving performance of the DAB glass antenna, by providing the defogger with a vertical striation (particularly a plurality of vertical striations), it is possible to It was found that the reception performance of a glass antenna for DAB can be improved. Therefore, when a defogger is provided with a vertical striation, especially when a plurality of vertical striations are provided on a defogger, even if the DAB glass antenna is placed on the upper side of the window glass, the DAB It was speculated that there is a possibility of improving the reception performance of glass antennas.

Note that in Example 21, the receiving performance of the DAB glass antenna deteriorates around 210 MHz. This is assumed to be caused by the generation of standing waves in the defogger 3 due to radio waves at a frequency of about 210 MHz.

That is, in Example 21, the length between the busbar parts 31 was 900 mm near the top end and 970 mm near the bottom end. Since the vertical striations 33 were added only at the center in the left-right direction, the pitch between each busbar section 31 and the vertical striations 33 was 450 mm to 485 mm (0.45 m to 0.485 m). This pitch range is included in the above range of F (0.44 m to 0.62 m) assuming DAB band 3. That is, according to the condition of Equation 1 above, in Example 21, it was assumed that a standing wave would occur in the defogger 3.

Therefore, by substituting 0.45m to 0.485m (450mm to 485mm) for F in Equation 1, substituting 3.0×10 ⁸ (m/s) for the speed of light c, and substituting 0.7 for K, we get The value of f is 216 MHz to 233 MHz. This value of f is slightly deviated from the frequency of 210 MHz at which the reception performance deteriorated, but this is thought to be due to the fact that the value of K was set to 0.7.

On the other hand, in Example 22, each pitch was 200 mm or 250 mm to 285 mm. In Example 23, each pitch was 100 mm, 150 mm to 185 mm, or 200 mm. That is, in Examples 22 and 23, the pitch between the adjacent vertical filament parts 33 and the pitch of the vertical filament parts 33 adjacent to the buster part 31 and the bus bar part 31 are equal to an integral multiple of F in the above equation 1. There wasn't. In Examples 22 and 23, the reception performance did not deteriorate at around 210 MHz as in Example 21. Therefore, it was found that the conditions under which a standing wave is generated in the defogger 3 and the reception performance of the DAB glass antenna is degraded can be derived from the above equation 1.

(5) Experiment 5: Length of vertical element when multiple vertical striations are provided Next, in this Experiment 5, five vertical striations are provided as illustrated in FIG. We investigated the effect of changing the length of the vertical element on the reception performance of the DAB glass antenna. FIG. 14 shows the state of Experiment 5.

First, a window glass according to Example 23 of Experiment 4 was prepared. In the window glass according to Example 23, the distance D1 between the defogger 3 and the DAB glass antenna 4 was 13.5 mm, and the distance from the lower side of the window glass to the defogger 3 was 138.5 mm. Then, while maintaining this distance D1, the length L1 of the vertical element 42 of the DAB glass antenna 4 is shortened by 20 mm, and the hot wire part 32 is newly provided below by the shortened length. Window glasses according to Examples 24 to 27 were obtained. In the window glasses according to Examples 23 to 27, the total length L1 of the vertical element 42 and length L2 of the horizontal element 43 was fixed at 240 mm. That is, in the window glasses according to Examples 24 to 27, the length L1 of the vertical element 42 of the DAB glass antenna 4 is 80 mm, 60 mm, 40 mm, and 20 mm, and the length L2 of the horizontal element 43 is 160 mm, 180 mm, They were 200 mm and 220 mm. Further, in the window glasses according to Examples 24 to 27, the distances from the lower side of the window glass to the defogger 3 were 118.5 mm, 98.5 mm, 78.5 mm, and 58.5 mm, respectively. For each of Examples 23 to 27, the sensitivity of each DAB glass antenna was measured in the same manner as in each experiment described above. Figures 15A and 15B show the results.

FIG. 15A shows the measurement results of sensitivity (gain) of Examples 23 to 27 for each frequency of DAB band 3. Further, FIG. 15B shows the average value of the sensitivity (gain) of each of Examples 23 to 27 in the DAB band 3. Comparing FIG. 9B and FIG. 11B above, when the defogger is provided with five vertical striations, even if the length of the vertical element of the DAB glass antenna is 20 mm, the reception sensitivity of the DAB glass antenna is It turns out that it is possible to guarantee Furthermore, as shown in FIGS. 11A and 11B, the reception sensitivity of the DAB glass antenna was particularly good in the window glasses according to Examples 23 to 25, and the reception sensitivity of the DAB glass antenna was particularly good in the window glass according to Example 26. Sensitivity decreased slightly. Therefore, by setting the distance from the bottom edge of the window glass to the defogger, in other words, the vertical range in which the DAB glass antenna can be installed, to 78.5 mm or more (for example, 80 mm), the DAB glass antenna with good reception sensitivity can be achieved. I found out that I can get an antenna. In each of Examples 24 to 27, the pitch between adjacent vertical line portions 33 and the pitch between vertical line portions 33 adjacent to buster portion 31 and bus bar portion 31 are the same as in Example 23 above. Therefore, in each of Examples 24 to 27, each pitch was not equal to an integer multiple of F in Equation 1, and it is considered that the generation of standing waves in the defogger 3 could be avoided.

(6) Experiment 6: Case in which the DAB glass antenna was placed on the top side of the window glass Next, in this experiment 6, the DAB glass antenna was placed on the top side of the window glass, as illustrated in Figure 16. In this case, the effect of changing the vertical length of the vertical element and the horizontal length of the horizontal element in the DAB glass antenna on the reception performance of the DAB glass antenna was investigated. FIG. 16 schematically illustrates window glasses according to Reference Examples 2 to 6 that constitute the L-shaped antenna in Experiment 6. Note that this experiment 6 is similar to experiment 2 above.

First, by setting the length L3 of the vertical element 52 in Comparative Example 1 of Experiment 1 to 240 mm, and setting the horizontal length of the ground wire portion 55 to 310 mm, a reference example having the same configuration as that of Comparative Example 1 was prepared. A window glass according to Example 1 was obtained. That is, in the DAB glass antenna 5 according to Reference Example 1, the length L4 of the horizontal element 53 is 0 mm.

Then, by shortening the length L3 of the vertical element 52 of Reference Example 1 and increasing the length L4 of the horizontal element 53, window glasses of Reference Examples 2 to 6 were obtained. In the DAB glass antennas 5 according to Reference Examples 2 to 6, the length L3 of the vertical element 52 is 100 mm, 80 mm, 60 mm, 40 mm, and 20 mm, and the length L4 of the horizontal element 53 is 130 mm, 150 mm, 170 mm, 190 mm, and 20 mm, respectively. It was set to 210 mm. That is, in Reference Examples 2 to 6, the vertical element 52 and the horizontal element 53 constituted an L-shaped antenna. For each of Reference Examples 2 to 6, the sensitivity of each DAB glass antenna was measured in the same manner as in each experiment described above. Figures 17A and 17B show the results.

FIG. 17A shows the measurement results of sensitivity (gain) of each of Reference Examples 1 to 6 for each frequency of DAB band 3. Further, FIG. 17B shows the average value of the sensitivity (gain) of each of Reference Examples 1 to 6 in the DAB band 3. As shown in FIGS. 17A and 17B, even when the DAB glass antenna is placed on the upper side of the window glass, the reception of the DAB glass antenna increases as the length L3 of the vertical element is shortened. It was found that performance deteriorated. In particular, as in Experiment 2 above, it was found that it is better to make the length of the vertical element 20 mm or more in order to ensure reception performance that can withstand receiving DAB (especially band 3) broadcasts. Ta.

(7) Experiment 7: Distance between the DAB glass antenna placed on the upper side of the window glass and the defogger Next, in this experiment 7, as illustrated in FIG. The effect of changing the distance D2 between the DAB glass antenna and the DAB glass antenna provided on the upper side of the window glass on the reception performance of the DAB glass antenna was investigated. FIG. 18 schematically illustrates a window glass according to Reference Example 7 in which two hot wire portions 32 are provided in Experiment 7. Note that this experiment 7 is similar to experiment 3 above.

First, a window glass according to Reference Example 7 was obtained by adding a defogger 3B having two hot wire parts 32 to the window glass according to Reference Example 2 in Experiment 6 above. In the window glass according to Reference Example 7, the interval between the two hot wire portions 32 was 32.5 mm. At this time, in the window glass according to Reference Example 7, the distance D2 between the defogger 3B and the DAB glass antenna 5 was 247.5 mm. Then, as illustrated in FIG. 18, window glasses according to Reference Examples 8 to 12 were obtained by increasing the hot wire portions 32 of the defogger 3B according to Reference Example 7 upwardly at a pitch of 32.5 mm. That is, in the window glasses according to Reference Examples 8 to 12, defoggers 3B each having 3 to 7 hot wire portions 32 are formed, and the distance D2 between the defogger 3B and the DAB glass antenna 5 is 215 mm and 182.5 mm, respectively. , 150mm, 117.5mm and 85mm. For each of Reference Examples 7 to 12, the sensitivity of each DAB glass antenna was measured in the same manner as in each of the experiments described above. Figures 19A and 19B show the results.

FIG. 19A shows the measurement results of sensitivity (gain) of Reference Examples 7 to 12 for each frequency of DAB band 3. Further, FIG. 19B shows the average value of the sensitivity (gain) of each of Reference Examples 7 to 12 in the DAB band 3. As shown in FIGS. 19A and 19B, the reception performance of the DAB glass antenna did not change significantly between Reference Examples 7 to 10, and slightly decreased in Reference Examples 11 and 12. Referring to FIG. 19A, in Reference Example 11, the sensitivity of the DAB glass antenna decreased near frequencies of 180 MHz and 240 MHz. Further, in Reference Example 12, the sensitivity of the DAB glass antenna decreased significantly in the frequency range of 180 MHz to 200 MHz.

Therefore, when the DAB glass antenna is placed on the top side of the window glass, if the defogger is brought closer than 85 mm from the DAB glass antenna, the sensitivity of the DAB glass antenna will decrease due to interference from the defogger. That's what I found out. Therefore, by comparing Experiment 3 and this Experiment 7, we found that the distance between the defogger and the DAB glass antenna, which is installed so that the defogger does not interfere with the reception of the signal of the DAB glass antenna, is It was found that placing it on the bottom side of the window glass requires less time than placing it on the top side of the window glass. In other words, these results show that placing the DAB glass antenna on the bottom side of the window glass, rather than on the top side, reduces the vertical installation range of the DAB glass antenna and improves reception performance. It has been shown that it can be improved.

(8) Experiment 8: Effect of vertical striations when the glass antenna for DAB is installed on the upper side of the window glass Next, in this experiment 8, as illustrated in FIG. The effect of providing a vertical striation on the reception performance of a DAB glass antenna when placed on the upper side of the glass was investigated. FIG. 20 illustrates window glasses according to Reference Examples 18 and 19 in which five vertical striations 33 are provided. Note that this Experiment 8 is similar to Experiment 4 above.

First, Reference Example 1 of Experiment 6 was prepared, in which a defogger was not provided and a linear antenna was configured. Further, Reference Example 3 of Experiment 6 was prepared, in which a defogger was not provided and an L-shaped antenna was configured. Furthermore, by providing the window glass according to Reference Example 3 with a defogger substantially similar to the defogger 3B according to Reference Example 12 in Experiment 7, a window glass according to Reference Example 13 in which the vertical striations were not provided was prepared. . Specifically, in the window glass defogger according to Reference Example 13, one hot wire part 32 was added at the top of the defogger 3B according to Reference Example 12 at a pitch of 20 mm. Therefore, in the window glass according to Reference Example 13, the distance D2 between the defogger 3B and the DAB glass antenna 5 was 85 mm, similar to the above-mentioned Reference Example 12. Note that the length between the busbar portions 31 of the defogger 3B according to Reference Example 13 was 900 mm near the upper end and 970 mm near the lower end, similarly to Example 13 above.

Then, as illustrated in FIG. 20, window glasses according to Reference Examples 14 to 19 were obtained by providing the defogger 3B according to Reference Example 13 with vertical striations 33. Specifically, in the window glass according to Reference Example 14, the vertical striation 33 was provided only in the center in the left-right direction. That is, in the window glass according to Reference Example 14, a total of one vertical striation 33 was provided.

Further, in each of the window glasses according to Reference Examples 15 to 17, one vertical striation 33 is provided at the center in the left-right direction, and one vertical striation 33 is provided in the left-right direction centering on the one vertical striation 33. The striated portions 33 are arranged symmetrically. That is, in each of the window glasses according to Reference Examples 15 to 17, a total of three vertical striations 33 were provided. In the window glasses according to Reference Examples 15 to 17, the distance W3 between each vertical striation 33 arranged in the left-right direction and the vertical striation 33 arranged in the center was 100 mm, 200 mm, and 300 mm, respectively.

Furthermore, in the window glasses according to Reference Examples 18 and 19, one vertical striation 33 is provided at the center in the left-right direction, and two vertical striations 33 are provided in the left-right direction centering on the one vertical striation 33. The striated portions 33 are arranged symmetrically. That is, in each of the window glasses according to Reference Examples 18 and 19, a total of five vertical striations 33 were provided. In the window glasses according to Reference Examples 18 and 19, the distance W3 between each vertical striation 33 arranged on the inside in the left-right direction and the vertical striation 33 disposed in the center was 100 mm and 200 mm, respectively. Further, in both the window glasses according to Reference Examples 18 and 19, the distance W4 between each of the vertical striations 33 disposed on the outside in the left-right direction and the vertical striation 33 disposed in the center was 300 mm. For each of Reference Examples 1, 3, and 13 to 19, the sensitivity of each DAB glass antenna was measured in the same manner as in each of the experiments described above. Figures 21A and 21B show the results.

FIG. 21A shows the measurement results of sensitivity (gain) of Reference Examples 3 and 13 to 19 for each frequency of DAB band 3. Further, FIG. 21B shows the average value of the sensitivity (gain) of each of Reference Examples 1, 3, and 13 to 19 in the DAB band 3. As shown in FIGS. 21A and 21B, the reception performance (sensitivity) of the DAB glass antenna was improved in Reference Examples 15 to 19 in which the defogger was provided with a vertical line portion. In particular, in Reference Examples 18 and 19 in which the defogger was provided with five vertical striations, the receiving performance (sensitivity) of the DAB glass antenna was favorably improved.

According to Experiments 1, 6, and 7 above, when the DAB glass antenna is placed on the upper side of the window glass, the DAB broadcast reception performance deteriorates and is more susceptible to the effects of the defogger. It has been shown that On the other hand, Reference Examples 15 to 19 are similar to Reference Example 12 of Experiment 7, in which one or more vertical striations are added to the defogger. That is, Reference Examples 15 to 19 are configurations in which the DAB glass antenna is placed on the upper side of the window glass, and the defogger is placed in the range where the receiving performance of the DAB glass antenna deteriorates in Experiment 7. Nevertheless, in Reference Examples 15 to 19, the sensitivity of the DAB glass antenna was improved, and better reception performance was obtained than in Reference Example 1, which did not include a defogger. Therefore, from this experiment 8, even if the DAB glass antenna is placed on the upper side of the window glass and the defogger is placed in the range where the reception performance of the DAB glass antenna is deteriorated in the above experiment 7, it is perpendicular to the defogger. It has been found that the reception performance of the DAB glass antenna can be improved by providing a linear portion (particularly a plurality of vertical linear portions). Therefore, when a defogger is provided with a vertical striation, especially when a plurality of vertical striations are provided on a defogger, even if the DAB glass antenna is placed on the upper side of the window glass, the DAB It has been shown that the reception performance of glass antennas can be improved.

Furthermore, in Reference Example 13, since the vertical striations are not provided, the pitch between the busbar parts 31 is 0.9m to 0.97m (900mm to 970mm), assuming DAB band 3. It was included in the range twice the above F (0.44 m to 0.62 m) derived from the above equation 1. Similarly, in Reference Example 14, since one vertical line portion 33 is provided at the center in the left-right direction, the pitch between each pass bar portion 31 and the vertical line portion 33 is between 0.45 m and 0.45 m. It was 485 m (450 mm to 485 mm). That is, in Reference Example 14, the pitch between each pass bar section 31 and the vertical line section 33 is F (0.44 m to 0.62 m), which is derived from the above equation 1 assuming band 3 of DAB. was included in the range. On the other hand, in Reference Examples 15 to 19, since each vertical line portion 33 is arranged as described above, the pitch between the bus bar portion 31 and the vertical line portion 33 adjacent to the bus bar portion 31 and the adjacent vertical line portion 33 are The pitch between the linear portions 33 was not an integral multiple of the above F.

Therefore, in Reference Examples 13 and 14, there is a frequency band in which the receiving performance of the DAB glass antenna is lower than in Reference Examples 15 to 19, and it is assumed that this is due to the generation of standing radio waves in the defogger. . In addition, from this, similar to Experiment 4 above, according to Equation 1 above, it is possible to derive a condition in which the reception performance of the DAB glass antenna decreases due to the generation of standing waves in the defogger 3. In other words, if the defogger receives radio waves, It was found that it is possible to predict whether or not standing waves will occur.

(9) Experiment 9: Simulation of the influence of vertical striations In Example 21 of Experiment 4 above, although one vertical striation was provided on the defogger, no vertical striation was provided on the defogger. The radio wave reception performance was lower in the vicinity of 170 MHz than in Example 20A. In order to investigate the cause of this, in Experiment 9, we investigated what kind of current distribution occurs in a window glass equipped with a defogger having vertical striations.

First, as illustrated in FIG. 22, a reference example 20 was set in which the defogger 3C was provided with one vertical linear portion 33. Conditions for each component according to Reference Example 20 are as follows.
・Length of top side of glass plate 2: 1030mm
・Length of the lower side of glass plate 2: 1200mm
・Vertical height of glass plate 2: 600mm
・Installation angle of glass plate 2: 20 degree inclination with respect to the vertical direction ・Number of hot wire parts 32: 12 ・Pitch of hot wire parts 32: 24 mm
・Horizontal length of defogger 3C (length of hot wire part 32): 1100mm
・Number of vertical striations 33: 1 ・Position of vertical striations 33: Center ・Length of vertical element 52: 160 mm
・Length of horizontal element 53: 200mm
・Distance D2 between DAB glass antenna 5 and defogger 3C: 10mm
・Defogger 3C line width: 1mm
・Line width of glass antenna 5 for DAB: 1mm
Note that the DAB glass antenna 5 was placed at a position 400 mm to the right from the center of the glass plate 2.

Further, a reference example 21 was set in which two vertical striations 33 were further added to reference example 20. The two vertical striations 33 were arranged at positions 300 pitch mm apart on both sides of the vertical striation 33 arranged at the center.

Then, for the window glasses of each reference example (20, 21) set in this way, DAB was performed using time domain three-dimensional electromagnetic field analysis software under the same conditions as in Experiments 1 to 8 above. A simulation was conducted in which Band 3 radio waves were emitted.
・Angular resolution: Measured by rotating the wagon 360 degrees every 3 degrees ・Frequency resolution: Measured every 1 MHz in the range of 174 MHz to 240 MHz ・Elevation angle between the radio wave transmission position and the antenna: 1.7 degrees (from the ground (The horizontal direction is 0 degrees and the zenith direction is 90 degrees.)
23A, 23B, 24A, 24B and 25 show the results.

23A and 23B show the current distribution in Reference Example 20. Specifically, FIG. 23A shows the current distribution when a 170 MHz radio wave is radiated to Reference Example 20. Further, FIG. 23B shows a current distribution when a 240 MHz radio wave is radiated to Reference Example 20. On the other hand, FIGS. 24A and 24B show the current distribution in Reference Example 21. Specifically, FIG. 24A shows the current distribution when a 170 MHz radio wave is radiated to Reference Example 21. Further, FIG. 24B shows a current distribution when a 240 MHz radio wave is radiated to Reference Example 21. Further, FIG. 25 shows simulation results of the sensitivity (gain) of each reference example (20, 21) for each frequency.

As shown in FIG. 23A, when a 170 MHz radio wave was emitted to Reference Example 20 provided with one vertical line portion 33, a standing wave of the radio wave was generated in the defogger of Reference Example 20. On the other hand, as shown in FIG. 23B, such standing waves were not generated in the defogger of Reference Example 20 when a 240 MHz radio wave was emitted. Furthermore, as shown in FIGS. 24A and 24B, in Reference Example 21 in which three vertical striations 33 were provided, no standing waves of the radio waves were generated even when radio waves of 170 MHz and 240 MHz were emitted.

Here, referring to FIG. 25, in Reference Example 20, the sensitivity decreased around 170 MHz where standing waves were generated. On the other hand, in the frequency band where no standing waves were generated (for example, 240 MHz), the sensitivities of Reference Examples 20 and 21 were approximately the same. That is, from this experiment 9, it was found that depending on the arrangement of the vertical striations, standing waves of radio waves are generated in the defogger, which deteriorates the receiving performance of the DAB glass antenna. Therefore, this experiment 9 showed that in order to prevent the reception performance of the DAB glass antenna from deteriorating, it is better to arrange the vertical striations so that such standing waves do not occur in the DAB frequency band. .

Specifically, in Reference Example 20, the pitch between each bus bar part 31 and the vertical striation part 33 is 0.55 m (550 mm), and the pitch between 0.44 m and 0.0 m assuming DAB band 3 is 0.55 m (550 mm). Included in the range of .62m. On the other hand, in Reference Example 21, the distances between the portion sandwiched between the bus bar portion and the vertical striation portion and the portion sandwiched between the adjacent vertical striation portions are 250 mm and 300 mm, respectively, and the distances are 250 mm and 300 mm, respectively. It was not equal to an integer multiple of F of 1. In Reference Example 21, as described above, no standing radio waves were generated in the defogger. Therefore, according to Equation 1 above, it has been found that it is possible to predict whether or not a standing radio wave will occur in the defogger. In other words, the distance between the part sandwiched between the bus bar part and the vertical line part and the part sandwiched between the adjacent vertical line parts is not equal to an integral multiple of F in the above equation 1. It has been found that by arranging the filamentous portion, it is possible to prevent the reception performance of the DAB glass antenna from deteriorating. Note that this decrease in reception performance is presumed to be due to DAB radio waves being trapped by the defogger. In other words, it is presumed that the defogger is in a state where it is easy to receive radio waves in that frequency band, which interferes with reception of radio waves by the DAB glass antenna.

(10) Experiment 10: Reception performance of other forms In this experiment 10, in order to investigate the reception performance of the DAB glass antenna of the form illustrated in Fig. 3C, we prepared examples (28, 29) shown in Fig. 26. . The conditions of the components according to Examples (28, 29) are as follows.
・Length of top side of glass plate 2: 1180mm
・Vertical height of glass plate 2: 340mm
- Number of hot wire parts 32: 9 - Pitch of hot wire parts 32: 27 mm (23 mm only at the bottom)
・Length of the lowest heating wire part 32: 1072mm
- Number of vertical striations 33: 3.
- Distance between bus bar part 31 and vertical striation part 33 (top): 260 mm
- Distance between the center vertical striation 33 and the right (left) vertical striation 33: 200 mm
・Vertical height of defogger 3: 212mm
・Length of horizontal element 43D: 150mm
・Length of ground wire portion 45D: 485mm
In the window glass of Example 28, the length of the vertical element 43D was 50 mm, and the distance D1 between the DAB glass antenna 4D and the defogger 3 was 5 mm. On the other hand, in the window glass of Example 29, the length of the vertical element 43D was 30 mm, and the distance D1 between the DAB glass antenna 4D and the defogger 3 was 25 mm. For Examples (28, 29), the sensitivity of each DAB glass antenna was measured in the same manner as in Experiment 1 above, except for the following two conditions.
・Glass plate installation angle: 45 degrees tilted at the bottom point in the vertical direction, 41 degrees tilted at the center point in the vertical direction, 37 degrees tilted at the top point in the vertical direction ・Frequency resolution: 174 MHz Measured every 3MHz in the range of ~240MHz

FIG. 27 shows the measurement results of sensitivity (gain) of each example (28, 29) for each frequency of DAB band 3. In the case where the glass plate is tilted from the vertical, and in the case where the length of the vertical element is short (Experiment 2 above), the reception performance of the DAB glass antenna can be significantly reduced. However, in each of the embodiments (28, 29), although the glass plate is relatively tilted from the vertical and the length of the vertical element 43D is relatively short, it is not possible to ensure a certain degree of reception performance. did it. This is because the glass antenna for DAB is arranged on the lower side of the window glass, and the pitch between the bus bar part and the vertical striations and between the adjacent vertical striations is equal to an integer multiple of F in the above equation 1. It is assumed that this is due to factors such as taking measures to prevent this from happening. In other words, it has been found that according to the features of the present invention, a certain degree of reception performance can be ensured even when the installation conditions of the DAB glass antenna are poor.

1...window glass,
2...Glass plate, 21...Upper side, 22...Lower side, 23...Left side, 24...Right side,
3... Defogger, 31... Bus bar part, 32... Heat wire part, 33... Vertical line part,
34...Connection part,
4... Glass antenna for DAB, 41... Power feeding part,
42...Vertical element (first element),
43...Horizontal element (second element),
44...Earth connection part, 45...Earth wire part,
5... DAB glass antenna, 51... Power feeding section,
52...Vertical element, 53...Horizontal element,
54...Earth connection part, 55...Earth wire part

Claims (3)

glass plate and
a DAB glass antenna formed on either side of the glass plate;
A pair of opposing busbar parts arranged below the DAB glass antenna, and a plurality of hot wire parts each extending in the horizontal direction and arranged in the vertical direction, both ends of which are respectively connected to the pair of busbar parts. a defogger having a plurality of connected hot wire parts;
Equipped with
The glass antenna for DAB is
a power supply unit disposed on the upper side of the glass plate;
a first element extending vertically from the power feeding section;
a second element extending horizontally and connecting to the first element;
a grounding connection part disposed near the power feeding part;
a ground wire portion connected to the ground connection portion and extending from the ground connection portion to a side opposite to the power feeding portion;
has
The defogger further includes one or more vertical linear portions extending in the vertical direction so as to intersect each of the plurality of hot wire portions,
The one or more vertical striations have a distance between a portion sandwiched between the busbar portion and the vertical striation, and a distance between the portion sandwiched between the adjacent vertical striations according to the following formula: arranged so as not to be equal to an integral multiple of F shown in 1,
Glass for vehicles.
F indicates the half wavelength of DAB radio waves,
λ ₀ indicates the wavelength of the DAB radio wave on the hot wire part,
K represents the wavelength shortening rate on the hot wire part,
c indicates the speed of light,
f indicates the frequency of DAB radio waves. The first element of the DAB glass antenna has a vertical length of 20 mm or more,
The vehicle glass according to claim 1 . The window glass for a vehicle is installed when parallel light is applied to the window glass from the horizontal direction, and the projected area of the window glass resulting from this is 0.5 ^m2 , and the window glass is installed with the horizontal direction as a reference. Attached to the vehicle window frame so that the angle is between 45 degrees and 75 degrees,
The vehicle glass according to claim 1 or 2 .