Antenna Unit

Abstract

To provide a versatile antenna unit that adapts to the usage situation and environment.SOLUTION: An antenna unit 11 includes an antenna 15, a holding member, a housing 21, and a matching circuit. The antenna 15 is formed in the shape of a long tape, includes a conductive portion, and has flexibility. The holding member holds one end of the antenna 15 in the longitudinal direction. The holding member is arranged inside the housing 21, the antenna 15 is housed in the housing 21, and a slit-shaped entrance / exit 25 is formed in which the antenna 15 is taken in and out from the other end 29 side in the longitudinal direction. One end of the matching circuit is connected to the conductive portion, and the other end is connected to a power supply.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an antenna unit. [Background technology]

[0002] Wireless power transmission is known as a technology that supplies power to a power receiving side that is far away from the power transmitting side. Power transmission methods include electric field coupling and magnetic field resonance. Wireless power transmission is used for charging smartphones, advertising using electronic paper, and supplying power to electronic shelf labels.

[0003] For example, Prior Document 1 discloses an electronic shelf label system that employs a magnetic resonance method. This electronic shelf label system generates a magnetic field by sending power to a coil, and supplies power between a power transmitting unit arranged on a rail and a power receiving unit provided on the label. Prior Document 2 discloses an electronic shelf label system that employs an electric field coupling method or a magnetic field coupling method. This electronic shelf label system includes a power transmitting device and a power receiving device. The power transmitting device has a transmission line that extends in one direction and is insulated except for both ends in the extension direction. The power transmitting device connects to an AC power source via an input end provided at a first end, and transmits power input via the input end to a second end. The power receiving device receives power by a coupler via an AC electric field or AC magnetic field leaking from an AC power transmission device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-014383 A [Patent Document 2] JP 2013-162626 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electronic shelf label system described in Prior Art 1 cannot be bent due to the coils provided. Therefore, this electronic shelf label system is difficult to install around curved shelves or cylinders, and lacks versatility in adapting to different situations and environments in which it is used. Furthermore, the location of the electronic shelf label may change depending on the rearrangement of products displayed on the shelves and the inventory status of products. However, the electronic shelf label system described in Prior Art 2 cannot accommodate rearrangements or the like using a single transmission line, and therefore lacks versatility.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide an antenna unit that is highly versatile and can be adapted to suit the situation and environment in which it is used. [Means for solving the problem]

[0007] The antenna unit of the present invention includes an antenna, a holding member, a housing, and a matching circuit. The antenna is formed in a long tape shape, has a conductive portion, and is flexible. The holding member holds one end of the antenna in the longitudinal direction. The housing has the holding member disposed therein, houses the antenna, and has a slit-shaped antenna entrance through which the antenna can be inserted and removed from the other end in the longitudinal direction. One end of the matching circuit is connected to the conductive portion, and the other end is connected to a power source. The holding member is a cylindrical core around which the antenna is wound and has a clamping portion that clamps one end of the antenna, and the housing has an axis on its inner wall that is inserted into the hollow portion of the core.

[0008] A matching circuit is preferably contained within the housing.

[0010] It is preferable that the winding core has a C-shaped cross section, is formed of an insulating material, and has a pair of winding core sections that hold one end of the antenna by clamping it between their one end faces, and a first conductive member formed of a conductive material and provided on one end face of the winding core sections in a state of contact with the conductive portion of the antenna.

[0011] It is preferable that the outer diameter of the shaft is smaller than the inner diameter of the winding core, a spiral spring is provided between the shaft and the winding core, and the outer peripheral surface of the spiral spring is in contact with the inner peripheral surface of the winding core.

[0012] It is preferable that the power spring is formed from a conductive material, the shaft is formed from an insulating material, extends in the axial direction, has a slit for holding the power spring, and has a second conductive member formed from a conductive material in the slit.

[0013] The other end of the matching circuit is preferably connected to a power source via a power spring. Effect of the Invention

[0014] According to the present invention, it is possible to realize an antenna unit with excellent versatility that can be adapted to the situation and environment in which it is used. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of an electronic shelf label device including an antenna unit according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the antenna unit. [Diagram 3] FIG. 2 is a schematic exploded view of the antenna unit. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 4 is an explanatory diagram of a matching circuit and a power spring. [Figure 7] FIG. 2 is a schematic diagram of a rotating shaft and a spiral spring. [Figure 8] FIG. 2 is a schematic diagram of an antenna. [Figure 9] FIG. 2 is a block diagram of the electronic shelf label device. [Figure 10] FIG. 4 is an explanatory diagram of a first matching circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The embodiment shown below is an example of the present invention, and the present invention is not limited to this example. An electronic shelf label device 10 shown in FIG. 1 includes an antenna unit 11, an electronic shelf label 12, and a shelf 13, which are an example of the present invention, and the electronic shelf label 12 is provided on the shelf 13 for use. The shelf 13 is used for displaying products in a store or stock items in a warehouse. The shelf 13 includes a shelf board 13a on which products or stock items are placed, and a plurality of supports 13b for holding the shelf board 13a horizontally, and the supports 13b are formed hollow. The electronic shelf label device 10 uses the antenna unit 11 connected to a power source 14, and connects the power source 14 and the antenna unit 11. The conductor L1 is arranged inside the support 13b, which is hollow. The antenna unit 11 is fixed to the support 13b, and an antenna 15 drawn out from the antenna unit 11 is arranged and fixed on the shelf 13. The electronic shelf label 12 is held by a holder 16 on the antenna 15. The antenna 15 transmits power supplied from the power source 14 to the electronic shelf label 12, and the electronic shelf label 12 receives power from the antenna 15. In this example, an electric field coupling method is adopted for power transmission and reception. From the viewpoint that the antenna 15 is stored in a housing 21 (see FIG. 2) as described later, it is preferable that the power transmission and reception be performed by the electric field coupling method. The antenna 15 will be described in detail later using another figure.

[0017] The electronic shelf label 12 includes a second electrode 86 (see FIG. 9) of the power receiving unit 83, a display unit 85 (see FIG. 9) using electronic paper, a power supply control unit 82 (see FIG. 9) that controls the output power, and a battery 84 (see FIG. 9). The electronic shelf label 12 functions as a power receiving device by including the second electrode 86. The configuration of the electronic shelf label 12 is not limited to this, and the type of the display unit 85 and the type of the battery 84 may be determined appropriately. The power supply 14 is an AC power supply. The antenna unit 11 may be used not only indoors but also outdoors. When the antenna unit 11 is used outdoors, the power supply 14 may be replaced with a DC power supply. When a DC power supply is used instead of the power supply 14, for example, a converter that converts DC to AC may be provided between the power supply 14 and the antenna 15. The holder 16 may be any device that can hold the electronic shelf label 12 detachably to the antenna 15, and may be, for example, a clip provided on the antenna 15 or a protruding member (not shown) provided to protrude from the antenna 15. When a protruding member is used as the holder 16, for example, a plurality of protruding members each having a bent tip may be formed, and the electronic shelf labels 12 may be fitted into the plurality of protruding members.

[0018] The antenna unit 11 transmits power supplied from the power source 14 to the power receiving unit 83 (see FIG. 9) of the electronic shelf label 12. The antenna unit 11 includes a housing 21 and an antenna 15 as shown in FIG. 2. The antenna 15 is flexible and formed in a long tape shape, and the housing 21 accommodates the antenna 15. The housing 21 has a housing upper part 22 that is an upper part when the housing is placed on the shelf 13, and a housing lower part 23 that is a lower part when the housing is placed on the shelf 13. An antenna entrance (hereinafter simply referred to as "entrance") 25 is formed in the housing lower part 23, and the antenna 15 is held by the housing 21 at one end 49 (see FIG. 4) in the longitudinal direction, and is inserted and removed through the entrance 25 from the other end 29 side in the longitudinal direction. A stopper 26 is provided at the other end 29 to prevent the other end 29 from entering the housing 21.

[0019] The housing 21 is cylindrical, and each end face, which is a perfect circle, is closed. The shape of the housing 21 may be determined according to the state in which the antenna 15 is housed. For example, when the antenna 15 is housed in a wound state, the housing 21 is preferably cylindrical in shape from the viewpoint of taking in and out the wound antenna, and when the antenna 15 is housed in a folded state, the housing 21 is preferably rectangular in shape. When the antenna 15 is housed in a folded state, the antenna 15 may have grooves (not shown) extending in the width direction perpendicular to the longitudinal direction, at equal intervals in the longitudinal direction, and alternately on one side and the other side in the longitudinal direction. This makes it easy to make mountain folds along the grooves, resulting in a folding structure that can be easily folded. However, the outer shape of the housing 21 may be determined by prioritizing the installation location and installation method of the antenna unit 11 over such a housing mode. In this example, the antenna 15 is housed in the housing 21 in a wound state, as described later.

[0020] The housing 21 is separable into an upper housing portion 22 and a lower housing portion 23. Since the housing 21 is thus separable, it is easy to perform maintenance on the inside of the housing 21 and the antenna 15. The housing 21 is not limited to a separable structure, and may be determined according to the situation and environment in which it is used.

[0021] The housing lower part 23 functions as a storage part for the antenna 15, and the housing upper part 22 functions as a lid. The entrance 25 is formed in a slit shape on the side surface, which is the circumferential surface of the housing lower part 23. In this example, the antenna 15 is stored in such a way that the width direction of the long antenna 15 in the rolled state coincides with the vertical direction in FIG. 2, and the entrance 25 is formed so that the extension direction of the entrance 25 coincides with the width direction of the antenna 15. As a result, the antenna 15 stored in the rolled state can be easily inserted and removed while being prevented from being bent. In addition, in order to remove foreign matter attached to the antenna 15 when used outdoors, for example, a brush-like brushed material 28 may be provided at the entrance 25, and is provided in this example as well. Therefore, dirt is removed by the brushed material 28 when the antenna 15 is inserted and removed. In addition, in order to prevent leakage current, a rubber frame material, for example, may be provided at the entrance 25 in addition to or instead of the brushed material 28.

[0022] The stopper 26 provided at the other end 29 of the antenna 15 functions as a pull-out member that is held by, for example, an operator with his / her fingertips when pulling out the antenna 15. By pulling the stopper 26 in a direction away from the housing 21, the housed antenna 15 is pulled out. Also, by releasing the force applied to the stopper 26 in the direction away from the housing 21, the antenna 15 is rewound. This allows the antenna 15 to be easily and quickly pulled out. The stopper 26 may be any size larger than the entrance / exit 25. Also, the stopper 26 used is one that extends longer than the short-side length (width) of the antenna 15, but the shape and size can be appropriately determined as long as the other end 29 of the antenna 15 can be kept outside the housing 21. A flange (not shown) is formed at the other end 29 of the antenna 15, and a groove (not shown) is formed in the stopper 26 in a shape corresponding to the flange, so that the stopper 26 fits into the other end 29 of the antenna 15.

[0023] Stopper 26 functions as a position-maintaining member for maintaining antenna 15 in the pulled-out position when pulled-out antenna 15 is placed in an upright position on shelf 13 (see FIG. 1). In this case, the shape of stopper 26 can be determined according to the shape of shelf 13 to be used.

[0024] As shown in FIG. 3, the antenna unit 11 includes a cylindrical core 31, and the antenna 15 is wound around the core 31 and housed in the lower housing part 23. The core 31 is cylindrical and has a perfect circular cross section. By forming the core 31 into a perfect circular shape, the antenna 15 is wound around the core 31 without any creases. As a result, the antenna 15 is not creased even when stored for a long period of time, and can be used and stored for a long period of time. A rotating shaft 32 is formed on the bottom surface inside the lower housing part 23 in an upright position. The rotating shaft 32 is fixed to the inner wall of the bottom surface of the lower housing part 23 so as not to rotate in the circumferential direction, and is an example of a shaft that is inserted through the hollow part of the core 31 and serves as the center of rotation of the core 31. The center of the bottom surface of the rotating shaft 32, which is a perfect circle, and the axis of the rotating shaft 32 are positioned so as to overlap on a straight line. The core 31 is attached to the rotating shaft 32 to be disposed inside the housing 21, and the wound antenna 15 is housed in the lower housing part 23. When storing the antenna 15, the other end 29 of the antenna 15 is brought out of the lower housing part 23 through the entrance 25, a stopper 26 is attached to the other end 29, and the upper housing part 22 is attached to the lower housing part 23.

[0025] As shown in FIG. 4, the winding core 31 has a cylindrical support member 41 extending in the axial direction, and a pair of winding core parts 42, 43 that are roughly halved along the axial direction, i.e., have a C-shaped cross section perpendicular to the axial direction. One end of each of the winding core parts 42, 43 is supported by the support member 41 and rotates around the support member 41. As a result, the winding core 31 is in an open state in which the ends of the winding core parts 42, 43 on the opposite side to the side supported by the support member 41 are separated from each other, and in a closed state in which they are in contact. In this example, the winding core 31 is in a closed state in which the winding core parts 42, 43 are biased to a closed state and one end 49 of the antenna 15 in the longitudinal direction is clamped. In the closed state, the part where the winding core parts 42, 43 clamp the antenna 15 is called a clamping part 45 (see FIG. 5), and the surface that contacts the antenna 15 is called a clamping surface 46. One end 49 of antenna 15 is clamped by clamping surface 46 and held by winding core 31. In this manner, winding core 31 is one example of a holding member that holds one end 49 of antenna 15. The holding method is not limited to clamping in this example, and antenna 15 may be held to winding core 31 by soldering, screws, bolts and nuts, adhesive, etc.

[0026] The winding core portions 42 and 43 are formed of an insulating material, and a first conductive member 47 is provided in the clamping portion 45, and the first conductive member 47 constitutes a clamping surface 46. The first conductive member 47 forms the entire surface of the clamping surface 46, and thus the first conductive member 47 comes into contact with the entire surface where one end 49 of the antenna 15 and the clamping surface 46 are in contact.

[0027] 5, the antenna 15 sandwiched by the winding core 31 includes a first electrode 51 and a first insulating material part 52 that covers the first electrode 51 and is formed of an insulating material, and one end 49 (see FIG. 4) of the antenna 15 has a part that is not covered by the first insulating material part 52. In the longitudinal direction of the antenna 15, the exposed part of the first electrode 51 that is not covered by the first insulating material part 52 is a sandwiched position 53 that is a target part to be sandwiched by the winding core 31.

[0028] The clamping portion 45 clamps the clamping position 53, and the clamping surface 46 contacts the clamping position 53. In FIG. 5, the portion of the first insulating material portion 52 above the first electrode 51 at the clamping position 53 is drawn with a two-dot chain line so that the covered first electrode 51 can be easily seen, and the internal first electrode 51 is shown with a solid line. That is, the first electrode 51 above the clamping position 53 is not actually exposed. The length L2 in the longitudinal direction of the antenna 15 at the clamping position 53 is formed to be smaller than the width L3 of the clamping surface 46 where the first conductive member 47 contacts the antenna 15. In this example, when the thickness direction of the antenna 15 is the vertical direction, the insulating material of the same thickness is removed from all surfaces except the top and bottom surfaces to expose the first electrode 51, forming the clamping position 53. By removing the insulating material from the top and bottom surfaces of the antenna 15 when the thickness direction is the up-down direction to provide the clamping position 53, the thickness of the clamping position 53 becomes thinner, so that the clamping force does not need to be too strong. This makes it possible to prevent breakage of the first electrode 51 and damage to the winding core 31. In addition, by insulating the top and bottom surfaces of the first electrode 51 in FIG. 5, there are no exposed portions of the first electrode 51 that are not in contact with the first conductive member 47, reducing the risk of electric leakage and the like.

[0029] The clamping position 53 may be a certain region including the edge of the antenna 15. In addition, in FIG.

[0030] As shown in FIG. 6, a circuit board 62 on which a first matching circuit 61 (see FIG. 9) is formed is embedded inside each of the winding cores 42 and 43, and a spiral spring 63 is provided in the hollow portion of the winding core 31. The first matching circuit 61 is for matching impedance values, which are complex numbers representing the resistance of each of the first electrodes 51. The circuit board 62 is embedded so as to be covered entirely by the winding cores 42 and 43 formed of an insulating material, and is disposed extending in the circumferential direction. One end 91 (see FIG. 10) of the first matching circuit 61 provided on the circuit board 62 extending in the circumferential direction is in contact with the first conductive member 47. The other end 92 (see FIG. 10) of the first matching circuit 61 on the support member 41 side is partially exposed as an exposed portion 65 from the winding cores 42 and 43. A spring end 66 of the spiral spring 63 is joined in a state of covering the exposed portion 65. The exposed portion 65 and the spring end 66 have shapes and sizes corresponding to each other. This allows the spring end 66 to be joined to the exposed portion 65 without any gaps.

[0031] The circuit board 62 is not limited to being disposed inside each of the winding cores 42 and 43, and may be disposed outside the antenna unit 11. When disposed outside the antenna unit 11, it is preferable to dispose the circuit board 62 between the power source 14 and the antenna 15, since this simplifies the work when replacing the power source 14 with another power source, since only the power source needs to be replaced.

[0032] An outer spring end 66 of the spiral spring 63 is joined to the circuit board 62, and thereby electrically connected to the other end 92 of the first matching circuit 61 (see FIG. 9). The spiral spring 63 applies a force pulling the one end 49 side of the antenna 15, and the antenna 15 is wound around the winding core 31 and accommodated in the housing 21. The length (width) of the spiral spring 63 in the short side direction may be any length that fits into the hollow portion of the winding core 31. Furthermore, the length in the long side direction is not limited as long as the function of the spiral spring 63, in this example, the function of winding up the pulled-out antenna 15, is not impaired.

[0033] In this example, the antenna 15 (see FIG. 6) is wound by the power spring 63, but the configuration may be such that the antenna 15 is wound without using the power spring 63. An example of winding the antenna 15 without using the power spring 63 is a configuration in which a handle (not shown) extending outside the housing 21 (see FIG. 2) is provided on, for example, a cylindrical winding core (not shown) that does not have the clamping portion 45, and the winding core is rotated in the circumferential direction by rotating the handle. In this configuration, the antenna 15 is manually wound. Specifically, the handle is fixed to one end of the winding core in the axial direction, and one end 49 (see FIG. 4) of the antenna 15 is fixed to the circumferential surface of the winding core. Since the handle is fixed to the winding core, the winding core rotates by turning the handle, and the antenna 15 drawn out to the other end 29 side is wound around the winding core 31. When antenna 15 is accommodated in housing 21 in a foldable manner, a fixed portion (not shown) is provided inside housing 21, and one end 49 of antenna 15 is fixed to this fixed portion. One end 49 of antenna 15 may be fixed to the winding core or fixed portion by any of the above-mentioned methods such as soldering, screws, bolts and nuts, adhesive, etc.

[0034] Since the outer diameter of the rotating shaft 32 is smaller than the inner diameter of the winding core 31, the spiral spring 63 is provided between the winding core 31 and the rotating shaft 32. The outer peripheral surface of the spiral spring 63 contacts the winding core 31, and a spring center 67 on the inner peripheral surface of the spiral spring 63 contacts the rotating shaft 32. The spiral spring 63 is formed of a conductive material. As a result, the spring end 66 is electrically connected to the circuit board 62, and the spiral spring 63 is also electrically connected to the rotating shaft 32.

[0035] As shown in Fig. 7, the power spring 63 is fixed by having the spring center 67 sandwiched in a slit 71 formed in the rotating shaft 32. The rotating shaft 32 has a first shaft portion 32a and a second shaft portion 32b formed in a semicylindrical shape with a semicircular cross section, and the slit 71 is formed as a gap between the first shaft portion 32a and the second shaft portion 32b. That is, the slit 71 extends from one of the top surface and the bottom surface of the rotating shaft 32 in Fig. 7 to the other. However, it is sufficient that the slit 71 is provided in a range such that the spring center 67 fits into a part of the space between the top surface and the bottom surface of the rotating shaft 32.

[0036] A second conductive member 72 is provided on a surface that defines a slit 71 between the first shaft portion 32a and the second shaft portion 32b, and is electrically connected to the power source 14 outside the antenna unit 11 by a conductor L1. As a result, power sent from the power source 14 is sent to the spiral spring 63 through the second conductive member 72. In this example, the spiral spring 63 and the second conductive member 72 are electrically connected by contacting each other, but the electrical connection is not limited to this. For example, a slip ring (not shown) is provided, and the other end 92 of the first matching circuit 61 (see FIG. 9) is connected to the power source through the slip ring. Small and hollow slip rings are generally known, and the type of slip ring may be appropriately determined according to the size of the antenna 15 and the size of the housing 21.

[0037] As shown in FIG. 8, the antenna 15 has two first electrodes 51 covered with a first insulating material portion 52. The antenna 15 has a length L4 of 900 mm, a width L5 of 30 mm, and a thickness L6 of 1.6 mm. The first electrode 51 has a length of 895 mm, a width L7 of 12 mm, and a thickness of 0.1 mm. The antenna 15 is flexible. The length and width of the antenna 15 may be appropriately determined according to the situation and environment in which it is used. The thickness of the antenna 15 is preferably thin from the viewpoint of being rolled up and stored. In FIG. 8, the thickness of the antenna 15 is greatly exaggerated relative to the width L7 of the first electrode 51. In FIG. 8, the clamping position 52 (see FIG. 5) is omitted in order to avoid complication of the figure.

[0038] The larger the cross-sectional area of ​​the first electrode 51 in the direction of width L5, the higher the efficiency of power transmission, i.e., the amount of power transmission per unit time. For this reason, the first electrode 51 is preferably in the form of a plate or sheet, which can be formed to have a larger cross-sectional area than those of a line or rod, even if the thickness is about the same as those of the line or rod. Also, from the viewpoint of storage, it is preferable that the first electrode 51 is in the form of a thin, flat plate or sheet. The antenna 15 in this example has two first electrodes 51, but the number of first electrodes 51 may be three. From the viewpoint of bending or folding the antenna 15, it is preferable that the first insulating material portion 52 is elastically deformable, and for example, silicone is preferable.

[0039] The antenna 15 may further include a ground member (not shown) made of metal. The ground member is a member for determining a reference potential in an electric circuit and an electronic circuit, so the shape and the position inside the antenna 15 may be appropriately determined as long as the function is not impaired. In the present embodiment, when a ground member is provided, the ground member is disposed inside the antenna 15 to determine a reference potential of the first electrode 51 in the antenna 15. The ground member is formed of a sheet-like metal, and may be disposed so that the longitudinal direction of the ground member is parallel to the longitudinal direction of the first electrode 51. In particular, when there are two first electrodes 51, providing the ground member reduces leakage of magnetic flux. Reducing leakage of magnetic flux improves power supply efficiency.

[0040] As shown in FIG. 9 , the electronic shelf label 12 has a power supply control unit 82, a power receiving unit 83, a battery 84, and a display unit 85. The power receiving unit 83 is connected to the power supply control unit 82, and the power supply control unit 82 is connected to the battery 84 and the display unit 85. The power supply control unit 82 controls the power receiving unit 83 to output the received power to the battery 84 or the display unit 85, and also functions as a so-called regulator that controls to keep the current and voltage constant. By connecting the power supply control unit 82 to the power receiving unit 83, the display unit 85, and the battery 84, the power sent from the power receiving unit 83 to the power supply control unit 82 is output to the battery 84 or to the display unit 85. The battery 84 stores power using the power output from the power supply control unit 82. The power supply control unit 82 also controls the power stored in the battery 84 to be output to the display unit 85. As a result, even if power is not being supplied from the power receiving unit 83 to the power supply control unit 82, the power supply control unit 82 supplies power from the battery 84 to the display unit 85, so that the display unit 85 displays predetermined information.

[0041] The power receiving unit 83 has a second electrode 86, a second insulating material part (not shown), a second matching circuit 87, and a rectifier part 88. The second electrode 86 is covered with the second insulating material part. The second electrode 86 is connected to the second matching circuit 87 and the rectifier part 88, and power is supplied to the power supply control unit 82. Since the second electrode 86 is covered with the second insulating material part, even if an operator touches the power receiving unit 83, he or she will not receive an electric shock. In addition, since the second matching circuit 87 functions as a resonant circuit, the power receiving unit 83 receives power transmitted from the antenna 15. The rectifier part 88 is for converting AC power into DC power. For example, it is an inverter.

[0042] The power source 14 is connected to the first matching circuit 61, and the first matching circuit 61 is connected to the first electrode 51. The first electrode 51 and the second electrode 86 are electrically connected, and thus the antenna unit 11 is electrically connected to the power receiving unit 83. The power supplied to the second electrode 86 is connected to the rectifier 88 via the second matching circuit 87, and the power is converted from AC to DC. The power source control unit 82 to which the rectifier 88 is connected is electrically connected to the display unit 85. As a result, power is supplied to the display unit 85, and predetermined information is displayed on the display unit 85. In addition, the battery 84 is connected to the power source control unit 82. The power is converted from AC to DC by the rectifier 88, and the battery 84 is electrically connected to the power source control unit 82, so that the battery 84 is stored. The power from the power source 14 passes through the first matching circuit 61 and the second matching circuit 87, and thus impedance matching is achieved.

[0043] 10, the first matching circuit 61 has one end 91 electrically connected to the first conductive member 47 and the other end 92 electrically connected to the spiral spring 63. Power sent from the power source 14 to the spiral spring 63 is sent to the first conductive member 47 via the first matching circuit 61 on the circuit board 62. As a result, power is supplied to the antenna 15 electrically connected to the first conductive member 47. The second matching circuit 87 has one end connected to the second electrode 86 and the other end connected to the rectifier 88. The structure of the second matching circuit 87 is similar to that of the first matching circuit 61, and therefore will not be described.

[0044] Next, the operation of the above-mentioned configuration will be described. The antenna 15 is housed in the housing 21 with one end 49 in the longitudinal direction held by the core 31, and is held by the stopper 26 with the other end 29 protruding from the housing 21. As shown in FIG. 2, the stopper 26 is moved in a direction away from the housing 21, whereby the tape-like antenna 15 wound around the core 31 is unwound and pulled out from the other end 29 to the outside of the housing 21. The entrance 25 is formed in a slit shape, and the antenna 15 is smoothly pulled out while being prevented from bending. The housing 21 and the stopper 26 are held in a predetermined position on the shelf 13, and the antenna 15 is arranged in a state where it is pulled out to a predetermined length. In this way, the antenna 15 is formed in a tape shape, and the length pulled out from the housing 21 can be freely set, so that it is easy to install on an installation target such as a curved shelf (not shown), and the antenna unit 11 is installed in a manner according to the situation and environment in which it is used, and is highly versatile.

[0045] A stopper 26 is provided at the other end 29 of the antenna 15, so that the antenna 15 can be quickly pulled out from the entrance 25 by pulling the stopper 26 with the fingers or the like, improving the ease of installation.

[0046] The antenna 15 is wound around the core 31 with one end 49 held by it, and the core 31 is attached to the rotating shaft 32 fixed to the housing 21 so as to be rotatable in one direction and the other direction. As a result, the core 31 rotates around the rotating shaft 32 while being supported by the rotating shaft 32, so that the core 31 rotates in one direction as the antenna 15 is pulled out. The core 31 rotates in the other direction, so that the antenna 15 is wound around the core 31. The antenna 15 is formed in a tape shape and has a flexibility sufficient to be wound around the core 31, so that the antenna 15 is stored in a state where it does not come out of the housing 21. The antenna unit 11 is thus compact and easy to store, transport, install, and perform other tasks.

[0047] 4, the winding core 31 rotates around the support member 41, and the clamping portion 45 opens and closes as the winding core portions 42 and 43 move. Since the winding core portions 42 and 43 are biased toward the closed position that closes the winding core 31, the clamping surface 46 holds the clamping position 53 of the antenna 15 in a clamped state. However, since the clamping portion 45 is for holding the clamping position 53 in a clamped state, the winding core portions 42 and 43 do not have to be biased toward the closed position as long as they are configured to hold the antenna 15 in a clamped state.

[0048] The clamping portion 45 holds the antenna 15 in a state in which the first conductive member 47 is in contact with the first electrode 51 exposed at the clamping position 53. This allows the first conductive member 47 and the first electrode 51 to be electrically connected to each other.

[0049] As shown in FIG. 6, the first conductive member 47 is joined to a first matching circuit 61 (see FIG. 9), and the first matching circuit 61 is joined to a spring end 66 at an exposed portion 65. The exposed portion 65 exposes the first matching circuit 61 from the winding core portions 42 and 43. Therefore, the spring end 66 contacts the exposed portion 65. That is, the spring end 66 contacts the first matching circuit 61 exposed from the exposed portion 65. As a result, power is sent from the spring end 66 to the first conductive member 47 via the first matching circuit 61. Then, the power is sent to the first electrode 51 electrically connected to the first conductive member 47. In this manner, power is sent to the antenna 15.

[0050] The circuit board 62 on which the first matching circuit 61 is formed is embedded inside the winding core 31. This prevents the first matching circuit 61 from being damaged by a load due to an external force.

[0051] A power spring 63 is provided inside the winding core 31, and a spring end 66 is joined to the exposed portion 65. Because the power spring 63 is provided, the portion of the antenna 15 that was pulled out from the opening 25 is wound around the winding core 31 and accommodated in the housing 21. When the spring center 67 rotates due to the rotation of the rotating shaft 32, an inwardly wound portion 68 (see FIG. 6) in the longitudinal direction of the power spring 63 is wound in the direction of rotation of the spring center 67, generating a spring force. However, since the spring end 66 does not rotate, the connection with the first matching circuit 61 is not lost. In other words, even if the winding core 31 rotates, the electrical connection with the first matching circuit 61 is maintained.

[0052] The power spring 63 is made of a conductive material, and a spring center 67 is clamped in a slit 71 of the rotating shaft 32. As shown in Fig. 7, a second conductive member 72 connected to the power source 14 is provided in the slit 71, so that the power supplied from the power source 14 is sent from the second conductive member 72 to the spring center 67. The power spring 63 is electrically connected to the first matching circuit 61, so that it is conducted to the antenna 15 electrically connected to the first matching circuit 61 via the first conductive member 47, and transmits power. [Explanation of symbols]

[0053] 10 Electronic shelf label device 11 Antenna unit 12 Electronic shelf label 13 Shelves 13a Shelf 13b Post 14 Power supply 15 Antenna 16 Holder 21 Housing 25 Antenna entrance / exit 26 Stopper 28 Brushed material 31 Roll core 32 Rotation axis 42, 43 Winding core 45 Clamping part 47 First conductive member 51 1st electrode 52 1st Insulating Materials Division 53 Clamping position 61 1st matching circuit 63 Spiral Spring 71 Slit 72 Second conductive member 82 Power supply control unit 83 Power receiving unit 84 Battery 85 Display section 86 2nd electrode 87 Second matching circuit 88 Rectifier L1 conductor

Claims

1. A flexible antenna formed in a long tape shape and having a conductive portion; a holding member for holding one end of the antenna in a longitudinal direction; The holding member is disposed inside, the antenna is housed therein, and the antenna is rotatable in the longitudinal direction and the other directions. A housing having a slit-shaped antenna entrance and exit formed therein for insertion and removal from an end side; a matching circuit having one end connected to the conductive portion and the other end connected to a power source; Equipped with the holding member is a cylindrical winding core around which the antenna is wound, and has a clamping portion that clamps the one end of the antenna, The housing is an antenna unit having an axis on its inner wall that is inserted into the hollow portion of the winding core.

2. The antenna unit according to claim 1 , wherein the matching circuit is accommodated in the housing.

3. The winding core is a pair of winding cores each having a C-shaped cross section, each made of an insulating material, and configured to sandwich and hold the one end of the antenna between one end surfaces of the pair of winding cores; 3. The antenna unit according to claim 1, further comprising: a first conductive member made of a conductive material and provided on one end surface of the winding core in a state of contact with the conductive portion of the antenna.

4. The outer diameter of the shaft is smaller than the inner diameter of the winding core, a power spring is provided between the shaft and the winding core, 4. The antenna unit according to claim 1, wherein an outer circumferential surface of the spiral spring is in contact with an inner circumferential surface of the winding core.

5. The power spring is made of a conductive material, 5. The antenna unit according to claim 4, wherein the shaft is made of an insulating material, extends in an axial direction, has a slit for holding the power spring therebetween, and has a second conductive member made of a conductive material in the slit.

6. 6. The antenna unit according to claim 5, wherein the other end of the matching circuit is connected to the power source via the power spring.

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