DESCRIPTION
Title of Invention: MARKER FOR MOBILE COMMUNICATION
Technical Field
5 [00011
The present invention relates to a marker which is a ground-fixed type
wireless communication unit to be used for wireless communication with a
mobile body such as an automobile or a railway vehicle, and specifically,
relates to a mounting structure of an electric circuit board for suppressing
10 temperature change of the board loaded on the marker.
Background Art
[oooal
As a marker for mobile communication, for example, a road surface
fixed-type marker to be used in communication with automobiles is known. As
15 such ground-fixed type marker, techniques disclosed in Patent Literature 1
and Patent Literature 2 are provided.
[00031
Patent Literature 1 discloses providing a marker having superior antishock
resistance, by configuring the marker by laminating, on an upper
20 surface of a radome material at an upper portion of an antenna stored inside
the marker, an impact absorbing material with a dielectric constant lower than
the dielectric constant of the radome material.
[00041
Patent Literature 2 discloses achieving adsorption of impact applied to
25 the marker, and inhibiting rainwater and the like from entering inside the
marker from an opening unit, by blocking the opening unit of the marker with
a first lid fitted to a stepped unit, and by blocking a gap between an outer
peripheral surface of the first lid and an inner peripheral surface of the
opening unit with a second lid.
30 Citation List
Patent Literature
[00051
[PTL 11 Japanese Patent Laid-Open Publication No. 11-258330
[PTL 21 Japanese Patent Laid-Open Publication No. 2003-209490
35 Summary of Invention
Technical Problem
[0006]
Explanation will be gven on the problem to be solved by the present
invention, with reference to FIG. 2. A marker 1 shown in FIG. 2 is a
generalized marker of the markers disclosed in Patent Literatures 1 and 2.
[00071
5 A major portion of the marker 1 is installed in an outdoor environment
where there is no roof. Therefore, the marker 1 is exposed to solar radiation 6
from the sun. A part of the solar radiation 6 is reflected on an upper surface
unit of a casing 7, but the remaining solar radiation energy is absorbed by a
casing material and converted to heat, and raises a surface temperature of the
10 casing. According to estimation by the present inventors, the casing surface
temperature reaches 100 "C or higher, depending on a combination of a
material characteristics of the casing and an environment of the installed
marker. The heat is transferred to an electric circuit board 9 by heat
conduction 8 via the casing 7 and a material 5 covering the board, and
15 consequently raises the temperature of the electric circuit board 9. On the
other hand, during nighttime, a phenomenon that the casing surface
temperature becomes lower than outdoor air temperature occurs, from heat
radiation from the upper surface of the casing 7 to the sky. That is, a variation
of the casing surface temperature becomes greater than a variation of the
20 outdoor air temperature in one day. If the variation of the casing surface
temperature is transmitted to the inside of the marker, the electronic circuit
board 9 will also be exposed to severe temperature variation.
[00081
In a case where the marker is placed in a severe environment in which
25 the temperature variation becomes significant, there is a problem that a
deterioration of lifetime of electronic components or soldered joint units on the
electronic circuit board 9 occurs. Further, during high temperature in the
daytime, there is a possibility that the electric circuit performs abnormal
operation from heat.
30 [0009]
As measures for the problem of temperature variation of the electronic
circuit board accompanying the variation of the casing surface temperature, it
is conceivable to use a material having low thermal conductivity such as an
urethane foam material as the material 5 covering the board. However, on the
35 other hand, the electronic components loaded on the board itself generate heat,
and it is necessary to dissipate the heat generated by the electronic
components to the outside of the casing. Therefore, in a structure where the
board is covered with a material with low thermal conductivity, it becomes
difficult to dissipate the heat generated by the electronic component to outside
the casing.
[oolol
The present invention aims at providing a marker capable of protecting
5 the board from the temperature variation caused by the solar radiation 6 and
radiative cooling at the upper surface of the casing 7, and radiating the heat
generated from the electronic components mounted on the board to the outside
of the marker efficiently.
Solution to Problem
10 [00111
In order to solve the above-mentioned problem, for example, a
configuration disclosed in the scope of the claims is adopted. The present
application contains a plurality of means for solving the above-mentioned
problem, and one example thereof is a marker for mobile communication
15 installed on ground, characterized in that the marker has an insulating layer
such as an air layer or a vacuum layer or a foam material layer or a fiber
material layer between an electronic circuit board and an upper portion of a
casing, and that the lower side portion from the electronic circuit board is
configured from only a material with larger heat conductivity than the
insulating layer.
[oo121
The "insulating layer" in the present application is not limited to the
air layer, the vacuum layer, the foam material layer, the fiber material layer,
or a layer configured from a member with remarkably high heat insulating
25 effect, but in a broad sense, widely includes a material with lower heat
conductivity than the member arranged to a lower side from the electronic
circuit board.
Advantageous Effects of Invention
[00131
30 It becomes possible to provide a marker capable of suppressing the
temperature variation of the electronic circuit board caused by the solar
radiation and the radiative cooling, and radiating the heat generated from the
electronic components mounted on the board to outside the marker with good
efficiency.
35 Brief Description of Drawings
Coo 141
[FIG. 11 FIG. 1 is a perspective view of an installation mode of a maker for
automobile.
[FIG. 21 FIG. 2 is a cross-sectional view taken at line A-A' in FIG. 1 of a
conventional marker.
[FIG. 31 FIG. 3 is an exploded view of the marker according to one mode of
Embodiment 1 of the present invention.
5 [FIG. 41 FIG. 4 is a perspective view of the marker viewed from an upper
surface side thereof according to one mode of Embodiment 1 of the present
invention.
[FIG. 51 FIG. 5 is a perspective view of the marker viewed from a lower surface
side thereof according to one mode of Embodiment 1 of the present invention.
10 [FIG. 61 FIG. 6 is a cross-sectional view taken at line B-B' in FIG. 4 of the
marker according to one mode of Embodiment 1 of the present invention.
[FIG. 71 FIG. 7 is a cross-sectional view taken at line B-B' in FIG. 4 of the
marker according to one mode of Embodiment 2 of the present invention.
[FIG. 81 FIG. 8 is a cross-sectional view of the marker according to one mode of
15 Embodiment 3 of the present invention.
[FIG. 91 FIG. 9 is a cross-sectional view of the marker according to one mode of
Embodiment 4 of the present invention.
[FIG. 101 FIG. 10 is a schematic diagram showing a wireless communication
between the marker and an antenna on a vehicle side.
20 Description of Embodiments
[OOl51
Various embodiments will be explained below with reference to
accompanying drawings.
Embodiment 1
25 [OOI~I
Explanation will be given on a wireless communication between a
marker and a vehicle, taking an automobile as an example of a mobile body,
with reference to FIG. 10. A marker 1 fixed on a road surface performs a
wireless communication 25 with an on-vehicle antenna 24 loaded on a vehicle
30 23 passing thereabove. For example, in a case where the marker 1 is installed
on a toll road or the like, it is possible for the marker 1 to receive information
such as the type of the vehicle, the entered toll gate and the like from the
vehicle 23, to compute a toll information calculated from these information, for
example, and to transmit the same to the vehicle 23. By doing so, it becomes
35 possible to collect a fare without stopping the vehicle 23. Further, it becomes
possible to transmit information of a speed limit of a traveling section or an
information of a curve or intersection on a route and the like to the vehicle 23,
process these information at the vehicl~2: 3 side, and notify the same as visual
information or voice information to a driver, or make the vehicle 23 decelerate
automatically to a safe speed after comparing the same with the speed and
acceleration of the vehicle 23. As is explained above, the wireless
communication in mobile communication is required to have high reliability,
5 since it is frequently used in managing money transfers or improvement of
safety.
[00171
An installation mode of the marker on the road surface is shown in
FIG. 1. As is shown in FIG. 1, a major portion of the marker 1 is installed
10 outdoors, so that the temperature of the marker 1 becomes higher than an
outdoor temperature from direct sunlight during daytime, and becomes lower
than the outdoor temperature from radiative cooling during nighttime. As
such, the marker is exposed to extremely severe temperature cycle
environment. If this temperature cycle reaches an electronic circuit board
15 inside the marker, there is a possibility that a life duration of electronic
components inside the marker or soldered joint units on the electronic circuits
may decrease, and also there is a possibility that an abnormal operation of the
electronic circuit occurs if the temperature increase of the electronic circuit
board becomes extremely high from solar radiation during the daytime.
20 [0018]
FIG. 3 is an exploded view of the marker according to the present
embodiment. The marker 1 is equipped with an upper casing unit 12
configuring an upper surface and side surfaces, a lower casing unit 13
configuring a lower surface, an electronic circuit board 9 loaded with an
25 electronic component and a wireless communication antenna, and an insert 14
for fixing a bolt, which is directly molded to the upper casing unit 12.
[OO1 91
The upper casing unit 12 and the lower casing unit 13 serve a purpose
of protecting the electronic circuit board 9 and the antenna existing inside
30 thereof from external environment, and is configured from a hard material
such as a FRP (Fiber Reinforced Plastic) which is a fiber-reinforced resin
material, taking into consideration an electric wave permeability in wireless
communication and a strength against vibration and crushing. Further, the
electronic circuit board 9 is sealed so that the whole surface is covered by a
35 rubber-like board sealing resin 11. Since the marker is fixed with respect to a
mount 10 by a bolt 2, the lower surface of the marker does not directly contact
the road surface or a base. A fixing method of the mount 10 to the road surface
or the base may be a method of directly fastening to the road surface or the
base via the bolt, or may be a method of fixing with a belt in a case of the base.
[00201
At an inner side of the lower casing unit 13, an inner wall 15 is
5 provided each to an outer peripheral unit and to a bolt piercing unit. When
manufacturing the marker, the electronic circuit board 9 is first installed to the
lower casing unit 13 while maintaining a gap between an inner bottom surface
of the lower casing unit 13, and thereafter, the board sealing resin 11 is
directly casted in a fluidized state, thereby making it possible to fix the
10 electronic circuit board 9 in a state closely contacting the lower casing unit 13,
and to cover the whole surface of the electronic circuit board 9 with the board
sealing resin 11. Thereafter, the upper casing unit 12 and the lower casing
unit 13 fixed with the electronic circuit board 9 are matched, and the marker
and the mount 10 are fixed with the bolt 2 and the insert 14 for fixing the bolt.
15 When matching the upper casing unit 12 and the lower casing unit 13, it
becomes possible to configure the marker having a space between an inner
upper surface of the upper casing unit 12 and the board sealing resin 11.
[002 11
FIG. 4 shows a perspective view of the marker seen from an upper
20 surface side thereof. The marker has two piercing units for fixing the marker
and the mount 10 with the bolts 2. Further, the side surface of the marker has
a connector for connecting the marker and a superior ground device with a
communication wire, and both side surfaces of the connector are equipped with
projecting units. When a vehicle passes the marker, foreign matters on the
25 road surface collide thereto by being flicked by tires and the like. Therefore, by
having such projecting units, it becomes possible to prevent the foreign matters
from colliding to a connecting portion between the marker and the
communication wire and damaging the connecting portion.
[00221
3 0 FIG. 5 shows a perspective view of the marker seen from a lower
surface side. As is shown in FIG. 5, the lower casing unit 13 is provided with
an unevenness unit 16. The unevenness unit is designed to increase a surface
area of the lower side surface of the casing, and to improve a heat radiation
effect from a lower side portion of the marker. Further, the lower casing unit
35 13 is arranged so as to enter into an inner side of a side surface unit of the
upper casing unit 12. With such configuration, it becomes possible to make it
difficult for rainwater to enter the interior of the marker. Further, if the
mount 10 is configured to cover the whole surface of the lower casing unit 13,
there is fear that the radiation performance from the lower side surface of the
lower casing unit 13 is deteriorated. Therefore, the mount 10 is configured to
cover a section of the lower casing unit 13.
100231
5 FIG. 6 shows a cross-sectional view taken at B-B', when the marker is
cut between B-B' shown in FIG. 4. In FIG. 6, the shaded area indicates a cut
surface. As is shown in FIG. 6, a space 17 is provided between the upper
casing unit 12 and the board sealing resin 11 covering the electronic circuit
board 9.
10 loo241
The space 17, that is, an air layer (which may be a gas layer other than
air) functions as an insulating layer as it is, and is capable of effectively
suppressing heat conduction from the upper surface unit of the marker which
becomes hot by solar radiation to the electronic circuit board 9. It is possible to
15 make the space 17 function as the insulating layer, for example, by installing
heat insulating material such as an urethane foam or a glass wool and the like.
Further, it is possible to further improve an insulating effect than that of the
air layer, by making the space to a vacuum state. In this case, it is not easy to
obtain a complete vacuum state, so that it is possible to exert a larger
20 insulating effect than that of the air layer, by filling the air layer with a lower
air pressure than the atmospheric pressure or other gas.
100251
Such structure is effective not only in protecting the electronic circuit
board 9 from the temperature rise from the solar radiation during daytime, but
25 also in protecting the electronic circuit board 9 from the temperature drop from
the radiative cooling during nighttime.
100261
On the other hand, the electronic circuit board 9 contacts the lower
casing unit 13 via the board sealing resin 11, so that the heat conduction with
30 the lower surface side of the marker becomes larger compared to that of the
upper surface side of the marker. In the day time, the lower surface side of the
marker is in the shade, so that there is no fear that the surface temperature of
the lower surface side of the marker rises by direct sunlight, unlike the case for
the upper surface side. The temperature rise during daytime of the road
35 surface or the base becomes large, since the road surface or the base is exposed
to direct sunlight. However, the lower surface of the marker does not contact
the road surface or the base directly from the mount 10, and most part of the
lower surface of the marker is configured to contact the outer air, therefore,
there is little effect of heat conduction from the road surface or the base which
became hot. As such, the temperature change of the lower side of the marker
is similar to ambient temperature change of the surroundings. Therefore, it is
preferable to load the electronic circuit board 9 to a lower side of the marker 1.
5 The mount 10 is equipped with a projecting unit 19 at a bolt joining portion,
and a space is provided between the lower surface of the marker and the
mount 10 by the projecting unit 19 when the mount 10 is fixed to the marker.
By providing a space between the lower surface of the marker and the mount
10, it becomes possible to secure a radiation effect from the lower surface of the
10 marker.
[00271
The problems to be considered in addition to the temperature rise from
solar radiation are the heat generation by elements mounted on the electronic
circuit board. The marker basically operates only during passing of the vehicle,
15 so that there is small possibility that regular heat generation from element
occurs. However, in a case where the vehicle stops in a state in which the onvehicle
antenna position and the marker position coincides, wireless electric
supply by the on-vehicle antenna continues, and there is a possibility that the
heat generation by the elements loaded to the marker increases. Supposing
20 that the board is covered by the same material as the insulating layer, the
effect of suppressing the temperature rise of the board from solar radiation
improves, but it has the opposite effect in radiating heat generated by the
element. Therefore, by adopting a rubber-like polyurethane-based potting
agent with high thermal conductivity (at least having higher thermal
25 conductivity than the insulating layer) and the like as the board sealing resin
11, it becomes possible to effectively dissipate the heat to the outside of the
element, and to suppress rise in element temperature during heat generation.
It is necessary to eventually dissipate the heat from the board sealing resin 11
to the outside of the marker. As is explained above, the temperature of the
30 upper surface side of the marker becomes high from the solar radiation, so that
it is preferable to aim at radiating heat from the lower surface side of the
casing in which the temperature is comparatively low. Further, the electronic
circuit board 9 and the inner side surface of the lower casing unit 13 are closely
contacted by the board sealing resin 11. By adopting the structure of the
35 present embodiment, it becomes possible to perform heat radiation effectively
from the lower side of the marker, since the electronic circuit board 9 is closer
to the lower surface of the marker than the upper surface thereof, and since no
insulating layer is provided to the lower side of the electronic circuit board 9.
The thickness of the board sealing resin 11 is preferably set to be as
thin as possible, taking into consideration a height of the electronic
components mounted on the electronic circuit board 9, fluidity of the sealing
5 resin during manufacturing, and a relationship between moisture permeability
and thickness and the like. By making the thickness of the sealing resin thin,
loading position of the board further approximates the lower surface of the
casing, and the heat radiation performance from the lower surface improves
further. Therefore, even in a case where the electronic components mounted
10 on the electronic circuit board 9 generates heat, the marker 1 of the present
configuration is capable of radiating heat effectively from the lower surface
side of the casing 7 the temperature of which is low.
[00291
Further, if materials with high dielectric loss exist in the surroundings
15 or in the vicinity of the antenna, power loss becomes large and the wireless
communication performance decreases. Therefore, it is necessary to give
attention to a mounting structure of the antenna upon designing, but
especially in a case where the antenna is mounted on to the electronic circuit
board, and a material with high dielectric loss is used for the board sealing
20 resin 11, there is a possibility that the wireless communication performance
decreases largely, since the antenna and the material with high dielectric loss
closely contact each other. Therefore, by making the thickness of the sealing
resin thin, it becomes possible to perform the wireless communication of the
antenna loaded to the electronic circuit board 9 satisfactorily.
25 [0030]
Further, there are cases where debris interrupting wireless
communication, such as powder of asphalt, iron powder, or water droplets,
adhere to the upper surface of the marker. In some cases, there is a possibility
that the marker 1 is flooded. In such case, compared to the case where the
30 antenna is set to the upper surface side of the marker casing, the present
structure is capable of securing large distance between the antenna loaded to
the electronic circuit board 9 and the debris adhering to the upper surface of
the marker. Therefore, it becomes possible to further reduce the attenuation
amount of the electric wave.
35 [00311
Further, since the marker is installed slightly above the road surface,
there is a possibility that the foreign matters collide to the lower surface of the
marker 1, by being flicked by tires and the like during passing of the vehicle.
Even in this case, by adopting the present structure of covering the lower side
of the marker with the lower casing unit 13, it becomes possible to protect the
electronic circuit board 9 from the collision of the foreign matters, since the
lower surface side of the casing is covered with hard material.
5 [00321
Further, in order to prevent moisture and the like from entering inside
the marker, it is desirable that an end of contacting surface unit 18 of the
upper casing unit 12 and the lower casing unit 13 takes a configuration to be at
the lower surface side of the marker to which raindrops do not directly fall.
10 That is, it is desirable that the lower casing unit 13 is arranged so as to enter
to the inner side of the side surface unit of the upper casing unit 12.
[00331
Further, to the lower surface side of the marker of the lower casing
unit 13, the unevenness unit 16 may be provided, as is shown in FIG. 5, so as
15 to increase the surface area thereof, and to aim at improving the heat radiation
effect from the lower side portion of the marker. Further, the lower side from
the wireless communication antenna does not become a transmitting surface of
the communication radio wave. Therefore, metal materials such as aluminum
alloy with higher thermal conductivity may be used for the lower casing unit
20 13.
Loo341
The marker in the above-explained embodiment is capable of
significantly reducing the heat conduction from the upper surface unit of the
casing to the electronic circuit board 9, with the insulating layer provided
25 between the upper surface unit of the casing and the electronic circuit board 9
sealed with resin. By doing so, it becomes possible to substantially suppress
the temperature rise of the electronic circuit board, even in a case where the
marker is placed under high solar radiation environment such as in lowlatitude
region, thereby making it possible to improve robustness of the
30 marker.
Loo351
Also, during nighttime, the surface temperature of the marker becomes
lower than the ambient temperature from heat radiation from the casing to the
outside, and in such case, it becomes possible to substantially suppress the
35 heat conduction from the electronic circuit board to the upper surface of the
casing with the above-explained insulating layer. As a result, it becomes
possible to further reduce the temperature variation of one day to which the
electronic circuit board is exposed. Thereby, it becomes possible to improve the
lifetime of the electronic components or the soldered joint units mounted on the
electronic circuit board, contributing to enhancement of long-term reliability of
the marker, even in a case where the marker is installed to an environment
with severe temperature environment.
5 [00361
On the other hand, by configuring the lower surface side of the casing
from the electronic circuit board with material having larger heat conduction
than that of the insulating layer, without providing the above-mentioned
insulating layer, it becomes possible to effectively release heat generated by
10 the electronic circuit components from the lower surface of the casing to which
no direct solar radiation reaches.
[00371
Further, in a case where the electronic circuit board is sealed with a
resin superior in heat conduction, with the aim of improving heat conduction to
15 the lower surface of the casing, it is possible to reduce the energy absorbed by
the board sealing resin, by taking a structure in which a part of or all of the
antenna for wireless communication is separated from the electronic circuit
board and is not sealed by the resin.
Embodiment 2
20 LO0381
In Embodiment 1, the structure of FIG. 6 in which the antenna for
wireless communication is loaded to the electronic circuit board 9 is adopted.
In Embodiment 2, the structure shown in FIG. 7, in which the antenna for
wireless communication is changed to a separated antenna 20 and is separated
25 from the electronic circuit board 9, is adopted. Other structure and
manufacturing method are the same as that in Embodiment 1.
[00391
In the structure of Embodiment 1, the board sealing resin 11 is filled
even on the antenna for wireless communication. Some of the resin material
30 used for the purpose of sealing the board has large dielectric loss. Therefore, in
a case where a resin with large dielectric loss is adopted in the structure of
Embodiment 1, wireless power loss is large, and there is a possibility that
reliability of the wireless communication deteriorates.
[00401
3 5 In such case, as is shown in FIG. 7, it is desirable to change the
antenna for wireless communication to the separated antenna 20, and to adopt
a structure in which the antenna is separated from the electronic circuit board
9. As an installing position of the separated antenna 20, a method of fixing the
same to the upper casing unit 12 is conceivable, however, the marker of the
present embodiment has the electronic circuit board 9 installed to the lower
casing unit, so that the wiring between the electronic circuit board 9 and the
separated antenna 20 or an assembly method thereof becomes complicated.
5 Therefore, it is desirable that the separated antenna 20 is installed to the
lower casing unit 13, and a method of fixing the separated antenna 20 to an
outer side or at an upper portion of the inner wall 15 is most appropriate.
Especially, when the latter method of fixing the separated antenna 20 to the
upper portion of the inner wall 15 is adopted, it becomes possible to offset the
10 height of an antenna plane and the height of the board sealing resin 11, so the
effect of suppressing wireless power loss becomes large.
Embodiment 3
[00411
In Embodiments 1 and 2, the marker casing is configured from two
15 members consisting of the upper casing unit 12 and the lower casing unit 13,
but on the other hand, Embodiment 3 adopts a structure in which only the
upper casing unit 12 exists and the lower casing unit 13 is omitted, as is shown
in FIG. 8. Other structure is the same as that in Embodiment 1. That is, it is
a structure in which the board sealing resin 11 configures the outer surface of
20 the lower portion of the marker. Further, in a case where an antenna for
performing communication with an on-vehicle side is arranged inside the
electronic circuit board 9, there is a technical request to arrange the electronic
circuit board to a position close to the upper surface of the marker in order to
improve the communication performance. However, in view of the heat from
25 the upper surface of the marker from solar radiation, there is a conflicting
technical request to arrange the electronic circuit board 9 to a position away
from the upper surface of the marker. As such, by configuring the board
sealing resin 11 with a material with larger thermal conductivity than a solid
insulating material 21 which covers the upper surface of the electronic circuit
30 board 9, as is in the present Embodiment, it becomes possible to make the
material arranged to the lower side of the electronic circuit board to be the
material with higher thermal conductivity than the material arranged to the
upper side of the electronic circuit board. With such configuration, it becomes
possible to secure communication performance, suppress heat quantity
35 transmitted from the upper surface of the marker to the electronic circuit
board minimum, and at the same time effectively perform heat radiation from
the lower surface side of the marker during heat generation from the circuit.
[00421
With such configuration, it becomes possible to arrange the electronic
circuit board 9 even closer to the lower surface of the marker, compared to
Embodiment 1 or 2. Therefore, it becomes possible to effectively promote the
heat radiation from the lower surface side of the casing. Further, the number
5 of components of the casing member may only be one, thereby contributing to
reducing the cost of the product. Still further, there is no connecting portion
between the casing units of the upper casing unit 12 and the lower casing unit
13 as is in Embodiment 1 or 2, so that it is an effective means for securing
watertightness of the electronic circuit board 9. Moreover, although not shown
10 in FIG. 8, by making the exterior side of the board sealing resin 11 in an
uneven shape, it becomes possible to aim at improving the heat radiation effect
from the lower side portion of the marker, by making the surface area of the
lower side surface of the casing larger.
Coo431
15 In the structure of Embodiment 1 or Embodiment 2, at the time of
manufacture, it is possible to seal the electronic circuit board 9 by casting the
board sealing resin 11 after fixing the electronic circuit board 9 to the lower
casing unit 13, but in the present Embodiment with no lower casing unit, it is
not possible to implement this manufacturing method. Therefore, in order to
20 realize the structure of the present Embodiment, the desirable manufacturing
method is preliminary filling the solid insulating material 21 such as a
urethane foam to the upper casing unit 12 and secure the thickness of the
insulating layer, thereafter installing the electronic circuit board 9 in a state
maintaining a gap between itself and the solid insulating material 21, and
25 thereafter casting the board sealing resin 11.
Coo441
In the present structure, the board sealing resin I1 becomes
exposed at the lower surface side of the marker, so the cooling performance is
high compared to that of Embodiment 1. However, it has a characteristic that
30 the strength with respect to collision of objects is low. Therefore, it is a
structure suitable for a marker which is installed on a road surface with no
possibility of collision of object from the lower surface of the marker.
Embodiment 4
COO451
3 5 As is explained above, in Embodiment 3, the board sealing resin 11 is
exposed at the lower surface side of the marker, so that the board protecting
performance from collision of foreign objects being flicked by tires and the like
during traveling of the vehicle drops, compared to Embodiment 1 and
Embodiment 2, in a case where soft material is used as the board sealing resin
11. In order to supplement this drawback, Embodiment 4 adopts a structure
in which a protecting unit 22 configured from a hard material is provided at
the lower surface portion of the board sealing resin 11, as is shown in FIG 9.
5 As a forming method of the protecting unit 22, a method of casting a hard resin
such as epoxy resin, a method of fixing a preliminarily-shaped FRP board or a
metal plate, and the like, may be given.
[00461
Other structure is similar to that in Embodiment 1.
10 Reference Signs List
[00471
1 marker
2 bolt
3 road surface
15 4 base
5 material covering board
6 solar radiation
7 casing
8 heat conduction
20 9 electronic circuit board
10 mount
11 board sealing resin
12 upper casing unit
13 lower casing unit
25 14 insert
15 inner wall
16 unevenness unit
17 space
18 joining surface end unit
30 19 projecting unit
20 separated antenna
21 solid insulating material
22 protecting unit
2 3 vehicle
35 24 on-vehicle antenna
2 5 wireless co~nmunication
WE CLAIM:
[Claim 11
A marker installed on ground, and which performs wireless
communication with a wireless communication device mounted on a mobile
5 body, comprising:
an electronic circuit board covered with resin material; and
a casing which covers at least an upper side which is the mobile body
side of the electronic circuit board;
wherein a first material or a space is provided between an upper side
10 portion of the casing and the electronic circuit board, and
a lower side from the electronic circuit board is configured from a
material with larger thermal conductivity than the first material or the space.
[Claim 21
15 The marker according to Claim 1, wherein the resin material is a
material with larger thermal conductivity than the first material or the space.
[Claim 31
The marker according to Claim 1 or 2, wherein the space is an air layer
20
[Claim 41
The marker according to Claim 1 or 2, wherein
an inside of the space is a gas layer filled with gas, and
the gas layer has a negative pressure with respect to outside air of the
25 marker.
[Claim 51
The marker according to Claim 1 or 2, wherein the first material is
configured from a foam material.
3 0
[Claim 61
The marker according to Claim 1 or 2, wherein the first material is
configured from a fiber material.
35 [Claim 71
The marker according to Claim 1, wherein the casing is configured so
as to cover an upper surface unit and a side surface unit and a lower surface
unit of the marker, and is divided into two components of a component in
which the upper surface unit and the side surface unit are configured
integrally, and a component configuring the lower surface unit.
[Claim 81
5 The marker according to Claim 1, wherein the electronic circuit board
is fixed to an inner side of the lower surface unit of the casing via the resin
material.
[Claim 91
10 The marker according to Claim 1, wherein
the casing is configured so as to cover an upper surface unit and a side
surface unit and a lower surface unit of the marker, and
the lower side unit of the cover has an uneven rectangular groove
shape.
15
[Claim 101
The marker according to Claim 1, wherein the electronic circuit board
is equipped with an electronic component and an antenna for wireless
communication.
2 0
[Claim 111
The marker according to Claim 1, further comprising an antenna for
wireless communication separately from the electronic circuit board, wherein
the antenna is not covered with the resin material.
25
[Claim 121
The marker according to Claim 11, wherein
the casing is configured so as to cover an upper surface unit and a side
surface unit and a lower surface unit of the marker, and is divided into two
30 components of a component in which the upper surface unit and the side
surface unit are configured integrally, and a component configuring the lower
surface unit, and
the antenna is installed to the component configuring the lower surface
unit of the casing.
3 5
[Claim 131
The marker according to Claim 11 or 12, wherein the antenna is
installed to a height different from the electronic circuit board.
[Claim 141
The marker according to Claim 1, wherein
the casing is configured from a single component with a structure
where the lower surface side is opened,
5 the first material is configured from a solid material, and
the resin material covering the electronic circuit board is adhered to
the first material configured from the solid material.
[Claim 151
10 The marker according to Claim 14, wherein
the lower surface of the marker is configured from the resin material
having an uneven shape at a surface thereof.