Magnetic marker

Abstract

A magnetic marker is a sheet-shaped magnetic marker (1) which is laid on a road surface in a manner that can be detected by a magnetic sensor installed on a vehicle and is used to implement vehicle-side control. The vehicle-side control is used to implement support for the vehicle's driving operation performed by the driver, or automatic driving that does not rely on the driver's operation. The magnetic marker is divided into a plurality of grid-shaped areas by a slit (1C) that cuts the magnet sheet (11) and the anti-slip layer (181) while leaving an adhesive layer (185). Therefore, when a part peels off, the area including the peeled part can be separated, and the peeling can be prevented from expanding.

Description

Technical Field

[0001] The present invention relates to a magnetic marker laid on a road to assist vehicle driving. Background Art

[0002] In the past, there is known a magnetic marker detection system for a vehicle using a magnetic marker laid on a road (for example, see Patent Document 1). The purpose of such a magnetic marker detection system is to provide various driving assistance such as automatic steering control and lane departure warning using magnetic markers laid along a lane for a vehicle equipped with a magnetic sensor.

[0003] As a magnetic marker, for example, a sheet-shaped magnetic marker is proposed (for example, refer to Patent Document 2). If it is a sheet-shaped magnetic marker, it can also be attached to the road surface. The construction of attaching the magnetic marker to the road surface without providing a receiving hole is low-cost, so the cost required for laying the magnetic marker can be reduced.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-202478

[0007] Patent Document 2: Japanese Patent Application Publication No. 2017-139402 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, if a magnetic marker attached to a road surface is used for a long period of time, there is a risk that the magnetic marker may be peeled off from the road surface.

[0010] The present invention has been made in view of the above-mentioned conventional problems, and aims to provide a sheet-shaped magnetic marker capable of minimizing the influence of peeling.

[0011] Solutions to Solve Problems

[0012] The present invention is a magnetic marker, which is a sheet-shaped magnetic marker laid on a road surface in a manner that can be detected by a magnetic sensor installed on a vehicle and is used to implement vehicle-side control, wherein the vehicle-side control is used to support the driving operation of the vehicle performed by the driver or to implement automatic driving that does not depend on the driver's operation, wherein:

[0013] The magnetic marker is divided into at least two areas by continuous or discontinuous slits.

[0014] Effects of the Invention

[0015] The magnetic marker of the present invention is divided into at least two regions by a slit. Therefore, in the case where peeling occurs in any region, the region can be separated by the slit. If the region where peeling occurs can be separated in this way, the risk of peeling spreading to other regions can be suppressed. The magnetic marker of the present invention has the excellent characteristics that the risk of peeling immediately spreading to the entire region is small and the influence of peeling can be suppressed to a minimum. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a stereogram of a magnetic marker.

[0017] Figure 2 It is a diagram showing the cross-sectional structure of a magnetic marker.

[0018] Figure 3 It is a figure which shows the structure of a magnet piece.

[0019] Figure 4 This is a front view of a piece (ground side) constituting the magnet piece.

[0020] Figure 5 It is a three-dimensional diagram of a wireless tag.

[0021] Figure 6 This is an explanatory diagram of the slit provided in the magnetic marker.

[0022] Figure 7 It is a front view of a magnetic marker with slits.

[0023] Figure 8 It is a flowchart showing the steps of making a magnetic marker.

[0024] Fig. 9 It is a three-dimensional image of the Thomson mold.

[0025] Fig.10 This is an explanatory diagram of the first cutting step.

[0026] Fig.11 This is an explanatory diagram of the second cutting step.

[0027] Fig.12 It is an explanatory diagram showing a magnetic marker held by a sheet-like substrate (liner).

[0028] Fig.13 This is an illustration of a stitch-like cut.

[0029] Fig.14 This is the front view of one of the other magnetic markers.

[0030] Fig.15 This is the front view of one of the other magnetic markers.

[0031] Fig.16 This is an explanatory diagram of one of the other slit windows.

[0032] Fig.17 This is an explanatory diagram of another slit window 2. DETAILED DESCRIPTION

[0033] The slit of the magnetic marker of the present invention can be a slit that penetrates in the thickness direction of the sheet-like magnetic marker, or a slit with a bottom that does not penetrate in the thickness direction. In the case of the slit that penetrates, it is preferred that the range that penetrates in the thickness direction is intermittently set, for example, like a needle trace. If it is a needle trace-shaped slit, even if the slit penetrates in the thickness direction, the magnetic marker will not be separated into a plurality of regions.

[0034] In addition, for example, in the case of a magnetic marker having a multi-layer structure including an adhesive layer composed of an adhesive material relative to the road surface, a magnetic layer composed of a magnetic material, and an anti-slip layer containing aggregates such as sand, a slit may be provided to leave any one layer and penetrate the other layers. Similarly, the slit in this case may be either an intermittent slit like a needle mark or a continuous slit.

[0035] Example

[0036] (Example 1)

[0037] This example is an example of a sheet-shaped magnetic marker 1 laid on the road surface in a manner that can be detected by a magnetic sensor installed on a vehicle. The magnetic marker 1 is used to achieve vehicle-side control, which is used to support the driving operation of the vehicle performed by the driver or to achieve automatic driving that does not depend on the driver's operation. For more information, refer to Figure 1 to Figure 17 Provide explanation.

[0038] Figure 1 The magnetic marker 1 illustrated in the figure is a road marker that is flat and circular with a diameter of 100 mm and can be bonded to the road surface. A grid-shaped slit 1C is provided on the surface of the magnetic marker 1. The slit 1C helps to separate the peeled area and prevent the peeling from expanding when the magnetic marker 1 peels off from the bonding surface with respect to the road surface.

[0039] like Figure 2 As shown, the magnetic marker 1 is a marker having layers including paving materials on both sides of a flat magnet sheet 11 having a diameter of 100 mm and a thickness of 2 mm. The layer on the ground side when the magnetic marker 1 is laid is an adhesive layer 185 using asphalt as a paving material as an adhesive material. The layer on the surface side facing the upper surface when laid is an anti-skid layer 181 in which aggregate is mixed in asphalt as a paving material. The thickness of the adhesive layer 185 is about 1 mm. The thickness of the anti-skid layer 181 is about 1 mm.

[0040] In addition to the anti-skid function of reducing the risk of tire slippage, the anti-skid layer 181 also has the function of serving as a protective layer for protecting the magnet sheet 11. The anti-skid layer 181 may also be a layer formed by an anti-skid tape as an adhesive tape with an anti-skid function. In addition, a protective layer without an anti-skid function may be used instead of the anti-skid layer 181. As such a protective layer, there is, for example, a PET (PolyEthylene Terephthalate) film. In addition, release paper may be attached to the adhesive layer 185 in advance. During construction, the release paper can be peeled off and attached to the road surface. If release paper is used, the risk of reduced adhesion of the adhesive layer 185 can be suppressed during storage, transportation, construction work, etc.

[0041] The magnet sheet 11 is formed by bonding sheets 11A and 11B having a diameter of 100 mm and a thickness of 1 mm (see Figure 3 . ). In detail, an adhesive layer composed of an adhesive material or the like is formed between the sheet 11A and the sheet 11B. The sheets 11A and 11B are an example of intermediate sheets as intermediate processed products. The sheets 11A and 11B are obtained by forming an isotropic ferrite rubber magnet into a sheet shape, and the isotropic ferrite rubber magnet is obtained by dispersing magnetic powder of iron oxide as a magnetic material in a polymer material (non-conductive material) as a base material. The sheets 11A and 11B are sheets in which magnetic powder is dispersed in a non-conductive polymer material, and therefore have electrical properties such as low electrical conductivity. In addition, the sheets 11A and 11B have magnetic properties such as a maximum energy product (BHmax) = 6.4 kJ / cubic meter.

[0042] Here, the magnetic properties of the magnet sheet 11 as a magnetic source are briefly described. The magnetic flux density Gs on the surface of the magnet sheet 11 is 45mT (milli-Tesla). For example, for magnet sheets used on white boards in offices, refrigerator doors at home, and magnet sheets for beginners' signs attached to vehicle bodies, the surface magnetic flux density is about 20 to 40 millitesla. By comparing with these magnet sheets, it can be intuitively understood that the magnetic force generated by the magnetic marker 1 of this example is a weak magnetic force that cannot function as a normal magnet for adsorbing metal objects.

[0043] As for the installation height of the magnetic sensor on the vehicle side, it is assumed that the height is in the range of about 100 to 250 mm based on the road surface. According to magnetic field analysis simulation, actual test, etc., the magnitude of the magnetism acting on the highest 250mm position of the magnetic marker 1 is 40μT (micro Tesla) or more. Magnetism of about 40μT can be detected with high reliability by a highly sensitive magnetic sensor such as an MI sensor. It should be noted that the MI sensor is a magnetic sensor that uses the MI (Magneto Impedance) effect, in which the impedance of a magnetically sensitive body such as an amorphous wire changes sensitively according to an external magnetic field.

[0044] The sheet 11A constituting the magnet sheet 11 is a sheet on the ground side, and the sheet 11B is a sheet on the front side. In the magnet sheet 11, an RFID tag (Radio Frequency IDentification, wireless tag) 2 for providing information to the vehicle side by wireless communication is disposed between the two sheets 11A and 11B.

[0045] The RFID tag 2 is attached to the surface of the sheet 11A, and a conductive layer 112 is formed which is not electrically connected to the RFID tag 2. The conductive layer 112 in this example is a silver paste layer formed by applying a silver paste as a conductive ink (an example of a conductive material). As the conductive ink, in addition to the silver paste, graphite paste, silver chloride paste, copper paste, nickel paste, etc. can also be used. In addition, a thin conductive layer made of a metal material can also be formed by sputtering, evaporation, etc.

[0046] The conductive layer 112 is provided over the entire area of ​​the surface of the sheet 11A, leaving the slit window 113 (see Figure 4 . ). The slit window 113 is a gap with a width of 2.5 mm and a length of 70 mm. The slit window 113 is formed along the radial direction of the circular sheet 11A. It should be noted that the length of the slit window 113 can also be set to 60 mm. The length of the slit window 113 is preferably set to about 60 mm to 70 mm. The RFID tag 2 is arranged on the inner side of the slit window 113 in a manner not to be in electrical contact with the conductive layer 112. In this example, the RFID tag 2 is located near the end of the slit window 113. The conductive layer 112 functions as a booster antenna (Booster Antenna, an example of a secondary antenna) that amplifies the radio waves received and transmitted by the RFID tag 2.

[0047] RFID tag 2( Figure 5) is an electronic component having an IC (Integrated Circuit) chip 27 mounted on the surface of a label sheet 20 as a sheet-like member. The RFID tag 2 is configured to operate using power supplied from the outside through wireless transmission, and to wirelessly transmit information stored in the IC chip 27. The RFID tag 2 is in the form of a square sheet with a size of 2 mm square and a thickness of 0.7 mm. The RFID tag 2 is arranged in the slit window 113 ( Figure 3 ) near the end.

[0048] The label sheet 20 is a sheet-like member cut out from a PET (PolyEthylene Terephthalate) film. An antenna pattern 231 is formed on the surface of the label sheet 20 as a printed pattern of a conductive ink composed of a silver paste. The antenna pattern 231 is in a ring shape with a notch, and a chip mounting area (not shown) for mounting an IC chip 27 is formed in the notch portion. If the IC chip 27 is bonded to the chip mounting area, the antenna pattern 231 is electrically connected to the IC chip 27. The IC chip 27 forms a processing circuit for information transmitted and received through wireless communication. The antenna 23 formed by the antenna pattern 231 transmits and receives radio waves superimposed with information when electrically connected to the IC chip 27.

[0049] The antenna 23 formed by the antenna pattern 231 has the function of a power supply antenna that generates an excitation current by electromagnetic induction from the outside and a communication antenna for wirelessly transmitting information. It should be noted that as a conductive ink for printing the antenna pattern 231, in addition to silver paste, graphite paste, silver chloride paste, copper paste, nickel paste, etc. can also be used. In addition, the antenna pattern 231 can also be formed by copper etching, etc. It should be noted that the conductive layer 112 as the above-mentioned booster antenna functions as a secondary antenna for amplifying the radio waves received and transmitted by the antenna 23 as an example of a primary antenna in a state of electrical non-contact with the antenna 23.

[0050] IC chip 27( Figure 5 ) is an electronic component in which semiconductor elements including ROM (Read Only Memory) and RAM (Random Access Memory) as storage means are mounted on the surface of a sheet-like substrate. The IC chip 27 includes a processing circuit for processing information provided to the vehicle side. The RFID tag 2 is manufactured by attaching the IC chip 27 to the surface of the above-mentioned tag sheet 20 as described above. For attaching the insertion type IC chip 27 provided with electrodes not shown in the figure, in addition to conductive adhesive materials, various bonding methods such as ultrasonic bonding and riveting bonding can be used.

[0051] It should be noted that, as the base material of the tag sheet 20 and the IC chip 27, resin films such as polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP), paper, etc. can be used. Furthermore, as the above-mentioned IC chip 27, it can be either a semiconductor element itself or a chip formed by encapsulating a semiconductor element using plastic resin, etc. In addition, the RFID tag is not limited to the structure of this example. Various RFID tags with different antenna shapes, IC chip forms, and IC chip configurations can be used.

[0052] like Figure 1 , Figure 6 as well as Figure 7 As shown, the magnetic marker 1 of this example is divided into a plurality of areas by a grid-shaped slit 1C. The slit 1C is set to leave the adhesive layer 185 and cut the anti-slip layer 181 and the magnet sheet 11. The interval between the slits 1C in the grid-shaped slit 1C that are parallel to each other is 14.3 mm. The slit 1C is set to avoid the RFID tag 2 accommodated inside the magnet sheet 11 (between the sheets 11A and 11B). That is, the RFID tag 2 is arranged on the inner side of any area in the grid-shaped area divided by the grid-shaped slit 1C.

[0053] The magnetic marker 1 having the above structure can be obtained by a process including steps P1 to P3. Figure 8 Steps are used to make it. Step P1 is a step of forming the isotropic ferrite rubber magnet into a sheet shape to make sheets 11A, 11B (intermediate sheets). Step P2 is a step of bonding sheets 11A, 11B with the RFID tag 2 sandwiched therebetween. Step P3 is a step of forming the slit 1C. In sheet 11A, a conductive layer 112 having a slit window 113 is formed over nearly the entire surface, and the RFID tag 2 is attached to the surface of sheet 11A corresponding to the inner side of the slit window 113. Therefore, if step P2 is implemented, a conductive layer 112 that amplifies the radio waves sent and received by the RFID tag 2 can be formed between the layers of sheets 11A, 11B.

[0054] In step P3, for example, Fig. 9 The Thomson mold 30 is used to form the slit 1C. The Thomson mold 30 in the figure is a mold in which a plurality of linear Thomson blades 31 are arranged in parallel at intervals of 14.3 mm. If the first cutting step is performed by bringing the Thomson mold 30 close to the mounting surface (not shown) of the magnetic marker 1 until a gap of 1 mm is formed, then Fig.10 As shown in FIG. 1 , the magnetic marker 1 can be cut off with the adhesive layer 185 of 1 mm thickness left, thereby the magnetic marker 1 can be divided into narrow and long areas. Afterwards, if the Thomson mold 30 is rotated 90 degrees relative to the magnetic marker 1 and a second cutting process is performed, as shown in FIG. Fig.11As shown in FIG. 1 , it is possible to form a slit 1C orthogonal to the slit 1C provided by the first cutting step described above. Figure 7 . ) For example, it can be formed by the two cutting steps as described above.

[0055] Next, the advantages of the magnetic marker 1 provided with the slit 1C will be described.

[0056] The magnetic markers laid on the road are also sometimes exposed to wind and rain and trampled by tires. If the use period of the magnetic marker 1 is long, there is a risk of reduction in the bonding force relative to the road surface and a gap between the road surface and the road surface, resulting in peeling from the road surface. If peeling occurs at one part of the joint surface, the possibility of the peeled area expanding is high. The peeled area is also sometimes accelerated to expand until the entire magnetic marker is peeled off.

[0057] On the other hand, the magnetic marker 1 of this example is divided into a plurality of grids by a grid-like slit 1C. For example, in the case where peeling occurs on a portion of the joint surface, the area to which the portion belongs can be separated by the slit 1C. Therefore, the possibility of the peeling of the magnetic marker 1 expanding is small, and the risk of the peeling of a portion reaching the peeling of the whole is small. In addition, even if one of the areas divided into grids is separated, the remaining other areas can be used to maintain the magnetic properties of the magnetic marker 1 to a certain extent, and the risk of the magnetic marker 1 being unable to be used on the vehicle side is small. As mentioned above, the magnetic marker 1 of this example acts on a position of 250 mm in height relative to the road surface and is more than 40 μT (micro Tesla). Even if the magnetic marker becomes smaller due to separation from the outer peripheral side corresponding to the peeling, it can be detected on the vehicle side if it is in a state where a magnetic field of more than 10 μT is applied to a position of 250 mm in height.

[0058] The area divided by the slit 1C is a thin and small sheet with a thickness of about 3mm and a size of 14.3mm square. If it is such a thin and small square sheet of peeling material, it will rotate under the action of air resistance and immediately lose power, unlike the block-shaped flying objects, and it is likely that it will not fly far. Therefore, the risk of the peeling material from the magnetic marker 1 hitting a vehicle or a person is extremely small. Even if it hits the peeling material, the degree of its impact is less than the impact caused by inevitable flying stones on the road. For example, an anti-skid layer 181 mixed with aggregates of various sizes can also be used. In this case, convex and concave are formed on the surface of the anti-skid layer 181, thereby increasing the air resistance when the peeling material rotates. If the peeling material is difficult to rotate, the distance it flies when it has been separated from the magnetic marker 1 can be suppressed. An anti-skid layer with a deviation in layer thickness can also be used. In this case, the air resistance when the peeling material rotates can be increased by the undulations on the surface of the anti-skid layer, and the center of gravity of the peeling material can be eccentric, thereby making it difficult for the peeling material to rotate. If the peeled material is difficult to rotate, the risk of it flying far away is reduced.

[0059] In addition, for example, the shape of the stripping object can also be set to a shape with a larger moment of inertia than a square shape. If it is a shape with a large moment of inertia, the stripping object separated from the magnetic marker is difficult to rotate and difficult to scatter to a distance. As a shape with a larger moment of inertia than a square shape, a rectangular shape, a parallelogram shape, a trapezoidal shape, etc. are considered. The slit can also be set in a way that the shape of the stripping object is not a symmetrical shape but an asymmetrical shape. In this case, the stripping object can be difficult to rotate. For example, the square shape is symmetrical up and down and also symmetrical left and right. If it is a trapezoid that is symmetrical left and right but asymmetrical up and down, the moment of inertia becomes larger than the square shape. And, if it is a trapezoid that is asymmetrical left and right and up and down, the moment of inertia becomes further larger.

[0060] It should be noted that the inventors conducted verification experiments and magnetic field analysis simulations on the effect of the slit 1C on the magnetic properties. As a result, the effect of the slit 1C that divides the magnet sheet 11 on the magnetic properties is extremely slight and at a level that can be ignored. In addition, the inventors also confirmed through verification experiments that the effect of the slit 1C on the antenna function of the conductive layer 112 is also slight and at a level that can be ignored.

[0061] In this example, a continuous slit 1C is illustrated in which the magnet sheet 11 and the anti-slip layer 181 are cut while leaving the adhesive layer 185. Alternatively, a slit may be used in which the iron sheet 11 and the adhesive layer 185 are cut while leaving the anti-slip layer 181. Alternatively, a slit may be used in which only the magnet sheet 11 is cut. In addition, for example, after a slit is formed in the magnet sheet 11 to divide the magnet sheet 11 into a plurality of areas, an anti-slip layer 181 and an adhesive layer 185 may be formed on both sides. It should be noted that a slit may be used in which half (0.5 mm) of the 1 mm thick adhesive layer 185 is left and the remaining half (0.5 mm) of the adhesive layer 185, the magnet sheet 11, and the anti-slip layer 181 are cut.

[0062] It should be noted that a sheet-shaped substrate 100 ( Fig.12). In this case, the magnetic marker 1 will not separate even if a slit 1C is provided that penetrates in the thickness direction. After the magnetic marker 1 in a single-sided state held by the substrate 100 is pressed and joined to the road surface, etc., the magnetic marker 1 can be transferred to the road surface by peeling off the substrate 100. In this case, if it is transferred and joined to the road surface, the magnetic marker 1 is not separated but is integrated. The substrate 100 preferably holds the surface of the anti-slip layer 181 side of the magnetic marker 1. In this case, the magnetic marker 1 can be pressed against the road surface for each substrate 100. It should be noted that the substrate 100 can be a single-piece substrate that holds the magnetic marker 1 individually, or a continuous strip-shaped substrate that holds multiple magnetic markers 1. The magnetic marker can also be held in a sandwiched manner using two sheet-like substrates. In this case, it is preferred to press the magnetic marker against the road surface after peeling off the substrate on the adhesive layer 185 side.

[0063] Instead of the continuous slit 1C shown in the example, an intermittent slit such as a stitch in which the cut portion 1K and the uncut portion 1P are repeatedly connected may be provided. Fig.13 The cut portion 1K of the needle trace may penetrate in the thickness direction, or only the anti-slip layer 181 and the magnet sheet 11 may be cut, or only the adhesive layer 185 and the magnet sheet 11 may be cut, or only the magnet sheet 11 may be cut. The length of the cut portion 1K may be, for example, 2 to 5 mm, and the length of the uncut portion 1P may be, for example, 1 to 2 mm.

[0064] In addition, instead of providing the slits 1C in a grid pattern, a plurality of concentric slits having different diameters and slits that divide the annular region divided by the plurality of concentric slits in the circumferential direction (e.g., radial slits) may be combined ( Fig.14 ). Or, Fig.15 In that way, radial radial slits and spiral slits can also be combined. It can also be only a plurality of concentric slits or spiral slits. In the case of a plurality of concentric slits or spiral slits, the possibility of gradually peeling off from the outer peripheral side is high. When the magnetic marker 1 peels off, it can be separated from the outer peripheral side of the magnetic marker 1 and its circular shape can be maintained. If the shape of the magnetic marker 1, which is originally a circular shape, can be maintained, the characteristics of the shape of the magnetic distribution of the surrounding magnetic marker 1 can be maintained. If the characteristics of the shape of the magnetic distribution can be maintained, the relationship between the shape of the magnetic distribution and the position of the magnetic marker is close to constant. For example, there is an application of determining the position of the magnetic marker based on the distribution of the magnetic measurement value of the magnetic sensor. Even if the magnetic marker peels off, if the change in the shape of the magnetic distribution of the surrounding magnetic marker is small, the risk of significantly reducing the accuracy of determining the position of the magnetic sensor is small.

[0065] In this example, two sheets 11A and 11B are bonded together to produce a magnetic marker 1 in which an RFID tag 2 is accommodated inside a magnetic sheet 11. In the magnetic marker 1 in which an RFID tag 2 is accommodated inside a magnetic sheet 11, the durability of the RFID tag 2 can be improved compared to a structure in which the RFID tag 2 is attached to the surface of the magnetic sheet 11 or the surface of the magnetic marker 1 itself. This is because the sheets 11A and 11B constituting the magnetic sheet 11 can function as protective sheets for the RFID tag 2.

[0066] In this example, sheet 11B on the surface side is attached to sheet 11A on the ground side to which RFID tag 2 is attached and on which conductive layer 112 is formed. Instead of this, a conductive layer may be provided on one of sheets 11A and 11B, and RFID tag 2 may be attached on the other side. The slit window and the RFID tag may be aligned in such a manner that the RFID tag is located on the inner side of the slit window formed in the conductive layer when sheets 11A and 11B are attached. Furthermore, a conductive layer 112 may be provided on the outer surface of the magnet sheet 11 in which the RFID tag 2 is accommodated. It should be noted that, in the case where the conductive layer 112 and the RFID tag 2 are arranged on different layers, the conductive layer 112 may be formed over the entire surface of the magnet sheet 11.

[0067] It should be noted that, in this example, the RFID tag 2 is arranged near the end of the slit window 113 of the conductive layer 112. The position of the RFID tag 2 in the slit window 113 can be appropriately adjusted. The optimal position of the RFID tag 2 in the slit window 113 is different depending on the relationship between the size of the long side direction of the slit window 113 and the wavelength of the radio wave received and transmitted by the RFID tag 2. It is preferred to consider the relationship between the size of the slit window 113 and the wavelength, and appropriately adjust the position of the RFID tag 2 to near the end of the slit window 113, near the center of the slit window 113, etc.

[0068] It should be noted that, in the case of the magnetic marker 1 of this example in which the slit 1C is provided so as to be separated from the outer peripheral side in accordance with the peeling from the road surface, the position of the RFID tag 2 is preferably near the center of the magnetic marker 1. When the RFID tag 2 is arranged near the end of the slit window, the slit window 113 may be formed into an arc shape, a spiral shape, or a bent shape, and the RFID tag 2 may be arranged at the end. Fig.16). In this case, the RFID tag 2 can be located near the center of the magnetic marker 1 while satisfying the requirements of the position of the RFID tag 2 in the slit window. In this case, even if the outer peripheral side of the magnetic marker 1 is separated, the risk of affecting the RFID tag 2 can be reduced, and the RFID tag 2 can transmit radio waves with high reliability. The RFID tag 2 can also be arranged near the center of the long side direction of the slit window extending radially along the circular magnetic marker 1.

[0069] Can also be substituted in Figure 3 , Figure 4 The slit window 113 shown in the examples is adopted Fig.17 The slit window 113 illustrated in the figure. The main part of the slit window 113 illustrated in the figure is narrower than the RFID tag 2. And, the label space 113S for configuring the RFID tag 2 is provided at the end of the slit window 113. The label space 113S is a square-shaped space that is one size larger than the square-shaped RFID tag 2. If the RFID tag 2 is configured in the label space 113S, a substantially constant gap G can be formed between the outer periphery of the square-shaped RFID tag 2 and the conductive layer 112. If the size of the gap G between the RFID tag 2 and the conductive layer 112 is appropriately set, the degree of electromagnetic coupling between the antenna 23 inside the RFID tag 2 and the secondary antenna formed by the conductive layer 112 is improved, and the sensitivity of the radio wave transmission and reception performed by the RFID tag 2 can be improved. It should be noted that, as the size of the gap G, for example, a size of about 0.25 mm to 0.5 mm, or about 0.1 mm to 1 mm can be set. In particular, if it is Fig.17 Such a square-shaped tag space 113S can be configured with a substantially constant gap G facing all four sides of the quadrilateral (square) RFID tag 2. If the gap G is configured in this way, the electromagnetic coupling degree between the antenna 23 inside the RFID tag 2 and the secondary antenna formed by the conductive layer 112 is further improved, and the sensitivity of the radio wave transmission and reception performed by the RFID tag 2 can be further improved.

[0070] In addition, a slender depression with a width of 2.5 mm and a length of 70 mm along the radial direction may be provided on the surface of the circular intermediate sheet composed of the isotropic ferrite rubber magnet, and then the conductive layer 112 may be formed on the surface other than the depression to form the slit window 113. Alternatively, the sheet 11A formed with the conductive layer 112 having the slit window 113 may be processed to make the inner side of the slit window 113 concave. As processing for concave, there are, for example, stamping processing, countersinking processing, etc. The concave inside the slit window 113 is useful for ensuring a storage space for the RFID tag 2 between the sheets 11A and 11B.

[0071] In addition, instead of laminating the two sheets 11A and 11B, a magnet sheet containing the RFID tag 2 may be produced by insert molding the RFID tag 2. In this case, a conductive foil such as copper foil may be insert molded together with the RFID tag 2. Alternatively, a conductive layer may be formed on the surface of the magnet sheet with the RFID tag 2 insert molded therein.

[0072] In this example, an integrated RFID tag 2 in which an IC chip 27 and an antenna 23 are arranged on the surface of a tag sheet 20 is illustrated, and a structural example in which the entire RFID tag 2 is housed inside a magnet sheet 11 is shown. In the case of an RFID tag in which an external antenna (primary antenna) is electrically connected to an IC chip forming a processing circuit, the IC chip may be housed inside the magnet sheet 11, and on the other hand, the antenna may be arranged on the surface of the magnet sheet 11. Alternatively, the antenna may be housed inside the magnet sheet 11, and on the other hand, the IC chip may be arranged on the surface of the magnet sheet. In this way, instead of housing the entire RFID tag inside the magnet sheet 11, a portion of the RFID tag may be housed inside the magnet sheet 11. In the case in which a portion of the RFID tag is housed inside the magnet sheet 11, the sheets 11A and 11B constituting the magnet sheet 11 may be used to protect a portion of the RFID tag. In this case, the durability of the RFID tag may be improved compared to the case in which the entire RFID tag is attached to the surface of the magnet sheet.

[0073] The sheets 11A and 11B in this example have electrical properties such as low electrical conductivity. Such electrical properties of sheets 11A and 11B play a very effective role in the operation of the RFID tag 2. For example, when the power required for the operation of the RFID tag 2 is wirelessly transmitted by electromagnetic induction, if eddy currents are generated inside the sheets 11A and 11B, the efficiency of power transmission is significantly impaired. If the sheets 11A and 11B are formed by molding magnetic powder, the internal resistance is high, so the eddy currents can be suppressed and power can be transmitted efficiently. Similarly, the radio waves sent by the RFID tag 2 are attenuated to a low degree inside the sheets 11A and 11B, so the radio waves sent by the RFID tag 2 can be received with high reliability on the vehicle side.

[0074] The magnetic marker 1 of this example is a magnetic marker having an adhesive layer 185 on the back of a magnet sheet 11 and an anti-skid layer 181 on the surface. Instead of the adhesive layer 185 or the anti-skid layer 181, a resin layer made of a resin material may be provided. Alternatively, a layer may be formed of a composite material in which a resin material is impregnated with glass fiber or the like. A resin layer may also be formed on the outer peripheral side of the magnetic marker. Instead of the anti-skid layer 181, a weather-resistant sheet with a small degree of deformation, discoloration, degradation, etc. in an outdoor environment may be used. As a weather-resistant sheet, for example, a sheet made of a resin material mixed with an ultraviolet absorber may also be used.

[0075] It should be noted that, in this example, the magnetic marker 1 is illustrated as having the RFID tag 2, but the RFID tag 2 is not an essential structure. Regarding the magnetic marker 1 not having the RFID tag 2, the technical concept of dividing into a plurality of areas by slits is also effective.

[0076] The specific examples of the present invention are described in detail above as in the embodiments, but these specific examples are only examples of the technology included in the technical solution. Of course, the technical solution should not be interpreted restrictively by the structure, numerical value, etc. of the specific example. The technical solution includes the known technology, the technology obtained by variously deforming, changing or appropriately combining the specific examples using the knowledge of those skilled in the art, etc.

[0077] Description of Reference Numerals

[0078] 1 Magnetic marker

[0079] 1C Slit

[0080] 11. Magnets

[0081] 11A, 11B (middle piece)

[0082] 112 Conductive layer (secondary antenna)

[0083] 113 Slit Window

[0084] 181 Anti-slip layer

[0085] 185 Adhesive layer

[0086] 2 RFID tags (wireless tags)

[0087] 20 Labels

[0088] 23 Antenna (primary antenna)

[0089] 27 IC chip (processing circuit).

Claims

1. A magnetic marker, which is a sheet-shaped magnetic marker laid on a road surface in a manner that can be detected by a magnetic sensor installed on a vehicle and is used to achieve vehicle-side control, wherein the vehicle-side control is used to achieve support for the driving operation of the vehicle performed by the driver or automatic driving that does not depend on the driver's operation, The magnetic marker is characterized in that The magnetic marker is composed of at least a layer of a magnet sheet as a sheet-shaped magnet, which is divided into at least two areas by a continuous or intermittent slit that cuts the magnet sheet in the thickness direction, and the at least two areas are not separated but are integrally joined to the road surface. Each of the at least two regions is configured to be separable from an adjacent region by the cut when peeled off from the road surface.

2. The magnetic marker according to claim 1, characterized in that: The slits are arranged in a lattice shape.

3. The magnetic marker according to claim 1, characterized in that: The slits include a plurality of concentric slits having the same center and different diameters, and slits for dividing the annular region divided by the plurality of concentric slits in the circumferential direction. The magnetic marker is constructed so that the region located on the outer peripheral side of the at least two regions constituting the magnetic marker can be separated from the adjacent inner peripheral side region by the slit, and the regions constituting the magnetic marker are peeled off from the outer peripheral side.

4. The magnetic marker according to claim 1, characterized in that: The magnetic marker is laminated with a layer of adhesive material for attachment to the road surface. The slit is formed so as to penetrate all layers except the adhesive material layer.

5. The magnetic marker according to claim 1, characterized in that: The magnetic marker includes a wireless tag that outputs information to the vehicle side through wireless communication, and the wireless tag has a processing circuit for processing information and a primary antenna electrically connected to the processing circuit in a manner capable of transmitting and receiving radio waves superimposed with information. The slit is formed to at least avoid the processing circuit and the primary antenna.

6. The magnetic marker according to claim 5, characterized in that: The wireless tag includes a secondary antenna for amplifying radio waves transmitted and received by the primary antenna in a state of being electrically non-contacted with the primary antenna, and the secondary antenna is divided into at least two areas by the slit.

7. The magnetic marker according to any one of claims 1 to 6, characterized in that: The slits are intermittent slits like needle traces in which the cut portions and the uncut portions are repeatedly connected and penetrate the magnetic marker in the thickness direction.

8. The magnetic marker according to any one of claims 1 to 6, characterized in that: The magnetic marker before being laid on the road surface is held on a sheet-like substrate that holds the magnetic marker. After the magnetic marker in a single-sided state held by the substrate is joined to the road surface, the magnetic marker can be transferred to the road surface by peeling off the substrate. The magnetic marker held by the substrate is divided into at least two areas by a continuous slit that penetrates in the thickness direction.

9. The magnetic marker according to any one of claims 1 to 6, characterized in that: The magnetic marker includes an anti-skid layer, which has an anti-skid function to reduce the risk of the tires of the vehicle slipping. The anti-slip layer is an anti-slip layer including aggregates of different sizes, or an anti-slip layer having a deviation in layer thickness.

10. The magnetic marker according to any one of claims 1 to 6, characterized in that: The shape when the regions have been separated is a shape having a larger moment of inertia than a square shape.

11. The magnetic marker according to claim 10, characterized in that: The shape of the regions when separated is an asymmetrical shape.

12. The magnetic marker according to claim 1, characterized in that: The magnetic marker is provided with spiral slits and radial slits. The magnetic marker is constructed so that the region located on the outer peripheral side of the at least two regions constituting the magnetic marker can be separated from the adjacent inner peripheral side region by the slit, and the regions constituting the magnetic marker are peeled off from the outer peripheral side.

Images