JP2005026989A - Antenna device and non-contact ic card reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device capable of stably performing communication with a non-contact IC card held in all directions against the antenna surface. <P>SOLUTION: The antenna device comprises a first antenna coil L1 that is composed of two loops so that the total area of a loop antenna is equally divided into two and generates magnetic fluxes in reverse directions from each loop section by energization; a second antenna coil L2 that is overlapped on the first antenna coil L1 in an insulated state for arrangement, is made of three loops aligned in a line on a plane, has the same area as the total area of the antenna of the first antenna coil L1 as a whole, sets the area ratio of the intermediate loop in the three loops to each loop at both sides to 2:1, and generates the magnetic fluxes in reverse directions from the intermediate loop and the loop sections at both ends by energization; and a third antenna coil that is overlapped in an insulated state to the first antenna coil L1 in a direction, where rotation is made by approximately 90 degree in the plane, for arrangement and has the same shape as the first antenna coil L1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device and a non-contact IC card reader / writer device that are employed in, for example, an automatic ticket gate, a wireless automatic toll collection system, etc., and perform wireless communication with a non-contact IC card.
[0002]
[Prior art]
In recent years, automatic ticket gates have been introduced to save labor in various toll collection sites. This automatic ticket gate takes in ticket media such as admission tickets, commuter passes, and train tickets when a user enters a facility such as a station premises or amusement facility, or enters a facility. Based on the ticket information stored in, a pass determination process is performed to determine whether or not to allow the user to pass.
[0003]
In recent years, ticket gate machines that perform ticket gate processing by performing wireless communication with a non-contact IC card that is a wireless communication medium have been put into practical use. Such a ticket gate is provided with a non-contact IC card reader / writer, which is a wireless communication device for performing wireless communication with a non-contact IC card, and is not in contact with the antenna portion of the non-contact IC card reader / writer. Ticket gate processing can be performed simply by tapping the IC card horizontally. In addition, toll collection using such a contactless IC card is also being considered for use in a toll collection system on a toll road.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-150993
[Problems to be solved by the invention]
However, the conventional non-contact IC card reader / writer has the following problems due to the single loop of the antenna. That is, when the non-contact IC card is placed horizontally on the antenna surface, the magnetic flux generated from the antenna of the non-contact IC card reader / writer passes through the antenna coil of the non-contact IC card, and therefore communicates with the non-contact IC card. However, when the contactless IC card is tilted perpendicular to the antenna surface, the magnetic flux generated from the antenna of the contactless IC card reader / writer does not pass through the antenna coil of the contactless IC card, so communication fails. There was a fear.
[0006]
The present invention is for solving such a problem, and an antenna device capable of performing stable communication with a non-contact IC card that is laid in any direction with respect to the antenna surface. An object is to provide a non-contact IC card reader / writer device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the antenna device of the present invention has two antenna coils, and each of these antenna coils is a loop antenna formed on a plane, and the total area of the loop antenna is reduced. The loops are divided into two equal parts, and are formed so as to generate magnetic fluxes in opposite directions from each loop portion when energized, and the two antenna coils are substantially in a plane with each other. It is characterized by being arranged in an insulated state in a direction rotated by 90 degrees. According to this antenna device, by switching and using individual antenna coils, even when the non-contact IC card is leaned horizontally as viewed from the user and tilted perpendicular to the antenna surface, the user can Communication with the non-contact IC card is assured in both cases where the posture is vertical when viewed and the device is tilted vertically with respect to the antenna surface.
[0008]
The antenna device of the present invention is a loop antenna formed on a plane, and is constituted by two loops so as to divide the total area of the loop antenna into two equal parts. A first antenna coil that generates magnetic fluxes in opposite directions from each other, and a second antenna coil that is disposed in an insulated state on the first antenna coil, and is formed by three loops arranged in a line on a plane. The overall area of the first antenna coil is the same as the total area of the loop antenna, and the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2: 1. And a second antenna coil for generating magnetic fluxes in opposite directions from the intermediate loop portion and the loop portions at both ends when energized. According to this antenna device, by switching and using individual antenna coils, when the non-contact IC card is folded vertically with respect to the antenna surface and when horizontally folded with respect to the antenna surface, In either state, communication with the non-contact IC card is guaranteed.
[0009]
Furthermore, the antenna device of the present invention is a loop antenna formed on a plane, and is constituted by two loops so as to divide the total area of the loop antenna into two equal parts. A first antenna coil that generates magnetic fluxes in opposite directions from each other, and a second antenna coil that is disposed in an insulated state on the first antenna coil, and is formed by three loops arranged in a line on a plane. The overall area of the first antenna coil is the same as the total area of the loop antenna, and the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2: 1. A second antenna coil that generates opposite magnetic fluxes from the intermediate loop portion and the loop portions at both ends when energized; and in-plane with respect to the first antenna coil. Are arranged to overlap in an insulated state in the rotated orientation about 90 degrees, characterized by comprising a third antenna coil having the same loop-shaped and the first antenna coil. According to this antenna device, by switching and using individual antenna coils, even when the non-contact IC card is leaned horizontally as viewed from the user and tilted perpendicular to the antenna surface, the user can In both cases of vertical orientation when viewed and tilted perpendicular to the antenna surface, communication with the non-contact IC card is guaranteed and the non-contact IC card is placed on the antenna surface. On the other hand, communication with a non-contact IC card is assured even when the device is placed horizontally.
[0010]
A non-contact IC card reader / writer device according to the present invention includes the antenna device described above as an antenna portion, and switching means for switching an antenna coil driven in the antenna portion.
[0011]
The non-contact IC card reader / writer device according to the present invention further includes a determination unit that sequentially switches antenna coils driven by the switching unit and determines an antenna coil used for communication with the non-contact IC card. Good.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a diagram schematically illustrating a configuration of an antenna device 100 according to an embodiment of the present invention, and FIGS. 2 to 5 are configurations of individual antenna coils L1, L2, L3, and L4 in the antenna device 100 of FIG. FIG.
[0014]
As shown in these drawings, this antenna device 100 is composed of four antenna coils L1, L2, L3, and L4, and these four antenna coils L1, L2, L3, and L4 are overlapped so that their surfaces are aligned with each other. The antenna support 1 is arranged. More specifically, the antenna device 100 is realized by sequentially forming the conductor patterns of the antenna coils L1, L2, L3, and L4 on the printed circuit board serving as the antenna support 1 through an insulating layer (not shown). Yes.
[0015]
Among these four antenna coils L1, L2, L3, and L4, the first antenna coil L1 is formed by an eight-shaped loop on a plane as shown in FIG. More specifically, the antenna coil L1 includes an antenna coil region L1A formed by one of the two loops separated by the intersection of the 8-shaped loops, and an antenna coil region L1B formed by the other loop. It consists of and. The antenna coil region L1A and the antenna coil region L1B have the same shape and area on the plane. That is, the antenna coil L1 has a certain width in the X-axis direction and is equally divided into the antenna coil region L1A and the antenna coil region L1B in the Y-axis direction.
[0016]
When a current in the direction of the arrow is passed through the antenna coil L1 from the terminal, a magnetic flux H1A is generated in the front direction of the paper at the center of one antenna coil region L1A, and toward the back of the paper at the center of the other antenna coil region L1B. Magnetic flux H1B is generated. The directions of the magnetic flux H1A and the magnetic flux H1A generated in each antenna coil region L1A and antenna coil region L1B are opposite. Therefore, as shown in FIG. 3, the boundary portion between the antenna coil region L1A and the antenna coil region L1B is substantially perpendicular to the surface of the first antenna coil L1, and the X axis and the Z axis. Suitable for communication with the magnetic flux H1C passing through the antenna device 2A of the contactless IC card 2 that is trapped in a substantially horizontal orientation with respect to the plane formed by The magnetic flux H1C in the opposite direction is formed.
[0017]
As shown in FIG. 4, the second first antenna coil L2 is obtained by adding another loop to the 8-shaped loop of the first antenna coil L1, that is, three antenna coil regions L2A, It is formed of L2B and L2C. The plane area relationship between these antenna coil regions L2A, L2B, and L2C is approximately L2B = L2A + L2C, and the area of the intermediate antenna coil region L2B is the sum of the areas of the antenna coil regions L2A and L2C on both sides. It is almost equal to the thing. More specifically, the widths in the X-axis direction of the antenna coil regions L2A, L2B, and L2C of the second antenna coil L1 are equal, and the relationship between the widths in the Y-axis direction is approximately L2B = L2A + L2C.
[0018]
When a current in the direction of the arrow flows through the second antenna coil L2 from the terminal, a magnetic flux H2A and a magnetic flux H2C in the front direction of the paper are generated in the antenna coil regions L2A and L2C on both sides, and a paper surface in the intermediate antenna coil region L2B. A magnetic flux H2B in the back direction is generated. The directions of the magnetic flux H2A and the magnetic flux H2C generated in the antenna coil regions L2A and L2C on both sides are opposite to the direction of the magnetic flux H2B generated in the intermediate antenna coil region L2B. Therefore, as shown in FIG. 5, the second antenna coil is provided at the boundary portion between the antenna coil region L2A and the antenna coil region L2B and at the boundary portion between the antenna coil region L2B and the antenna coil region L2C, respectively. A magnetic flux H2D and a magnetic flux H2E in a direction passing through the antenna 2A of the non-contact IC card 2 tilted almost horizontally with respect to the surface of L2, that is, a direction suitable for communication with the non-contact IC card 2 tilted in the same posture Magnetic fluxes H2D and H2E are formed.
[0019]
As shown in FIG. 6, the third antenna coil L3 is obtained by exchanging the directions of the X axis and the Y axis of the first antenna coil L1. That is, the first antenna coil L1 is disposed in a state of being rotated by 90 degrees or substantially 90 degrees in a plane formed by the X axis and the Y axis. Therefore, as shown in FIG. 7, the boundary between the antenna coil region L3A and the antenna coil region L3B is substantially perpendicular to the surface of the third antenna coil L3, and the Y axis and the Z axis. Suitable for communication with the magnetic flux H3C that passes through the antenna 2A of the non-contact IC card 2 that is trapped in a substantially horizontal orientation with respect to the plane formed by the contact, that is, the non-contact IC card 3 that is trapped in the same state. Directional magnetic flux H3C is formed.
[0020]
As shown in FIG. 8, the fourth antenna coil L4 is obtained by exchanging the directions of the X axis and the Y axis of the second antenna coil L2. That is, the second antenna coil L2 is disposed in a state of being rotated 90 degrees or substantially 90 degrees in a plane formed by the X axis and the Y axis. Therefore, as shown in FIG. 9, the fourth antenna coil L4 is provided at the boundary portion between the antenna coil region L4A and the antenna coil region L4B and at the boundary portion between the antenna coil region L4B and the antenna coil region L4C, respectively. The magnetic flux H4D and the magnetic flux H4E are oriented to pass through the antenna 2A of the non-contact IC card 2 that is tilted almost horizontally with respect to the surface, that is, the orientation suitable for communication with the non-contact IC card 2 that is tilted in the same posture. Magnetic fluxes H4D and H4E are formed.
[0021]
Note that both the second antenna coil L2 and the fourth antenna coil L4 form a magnetic field in a direction suitable for communication with a non-contact IC card that is placed almost horizontally with respect to the antenna surface. And not. Either one may be used. Moreover, there is no restriction | limiting in the lamination | stacking order of each said antenna coil to the antenna support body 1, You may laminate | stack each antenna coil in what order.
[0022]
In this way, this antenna device 100 is configured by combining a plurality of antenna coils L1, L2, L3, and L4 having different loop shapes and orientations, so that these antenna coils L1, L2, L3, and L4 are switched. By communicating with each other, the contactless IC card 2 can communicate with the contactless IC card 2 regardless of whether the contactless IC card 2 is trapped vertically or horizontally with respect to the antenna surface of the antenna device 100. It becomes.
[0023]
Next, a non-contact type IC card reader / writer device 200 using the antenna device 100 will be described.
[0024]
FIG. 10 is a diagram showing a configuration of the non-contact type IC card reader / writer device 200. As shown in the figure, the non-contact type IC card reader / writer device 200 includes a wireless device 3 and a host device 4. The wireless device 3 includes the antenna device 100 and the control device 5 described above. The control device 5 transmits / receives various commands and data to / from the host device 4 and controls the entire radio 3, and the non-contact IC card 2 based on the communication command transmitted from the host device 4. A wireless circuit 52 that performs the wireless communication, a tuning circuit 53 that determines the resonance frequency of the antenna device 100, and a switching circuit 54 that switches the antenna coils L1, L2, L3, and L4 of the antenna device 100. The control circuit 51 includes a CPU circuit that analyzes commands and data, a memory circuit that stores various data, and a logic circuit. The radio circuit 52 includes a modulation circuit that modulates command data input via the control circuit 51 and a demodulation circuit that demodulates data received via the antenna device 100.
[0025]
Next, the operation of the non-contact type IC card reader / writer device 200 will be described.
[0026]
FIG. 11 is a flowchart showing a processing procedure when the antenna coils L1, L2, L3, and L4 of the antenna device 100 are switched to perform wireless communication with the non-contact IC card 2. FIG. 12 is a diagram showing the switching timing of the antenna coils L1, L2, L3, and L4.
[0027]
First, the host device 4 searches which antenna coils L1, L2, L3, and L4 can perform wireless communication with the non-contact IC card 2 trapped by the antenna device 100. This is done as follows.
[0028]
The host device 4 sends a control signal (a in FIG. 12) for connecting the first antenna coil (assumed to be the first antenna coil L1) to the control circuit 51 of the control device 5. The control circuit 51 of the control device 5 outputs the selection signal S1 of the first antenna coil L1 to the switching circuit 54 by this control signal (step 1101). The switching circuit 54 allows only the first antenna coil L1 to function effectively as an antenna during the period when the selection signal S1 is ON. That is, a current is supplied to only the first antenna coil L1 out of the four antenna coils L1-L4 to function as an antenna.
[0029]
Thereafter, a communication command (C1 in FIG. 12) is transmitted from the host device 4 to the control circuit 51 of the wireless device 3 (step 1102). The command data transmitted from the host device 4 is modulated by the modulation circuit of the radio circuit 52 and transmitted to the non-contact IC card 2 through the first antenna coil L1 of the antenna device 100 via the switching circuit 54 and the tuning circuit 53. The The host device 4 starts a timer simultaneously with the transmission of the communication command.
[0030]
If there is no response from the non-contact IC card 2 even after the set time has elapsed (NO in step 1103, YES in step 1104), the host device 4 controls the control circuit 51 of the control device 5 to switch to the next antenna coil. Is supplied with control signals (b and c in FIG. 12). Based on these control signals, the control circuit 51 of the control device 5 turns off the selection signal S1 for the first antenna coil L1 (step 1106), and instead, the selection signal for the second antenna coil L2, which is the next antenna coil. S2 is turned on (step 1107). The switching circuit 54 allows only the second antenna coil L2 to function effectively as an antenna while the selection signal S2 is ON. That is, a current is passed through only the second antenna coil L2 out of the four antenna coils L1-L4 to function as an antenna.
[0031]
Thereafter, a communication command (C2 in FIG. 12) is transmitted from the host device 4 to the control circuit 51 of the wireless device 3, and the command data is transmitted to the non-contact IC card 2 through the second antenna coil L2 of the antenna device 100 ( Step 1108). The host device 4 starts a timer simultaneously with the transmission of the communication command, waits for a response from the non-contact IC card 2 as described above (step 1109), and responds from the non-contact IC card 2 even if the set time has elapsed. If there is no (NO in step 1109, YES in step 1110), the host device 4 sends a control signal (d, e in FIG. 12) to the control circuit 51 of the control device 5 so as to switch to the next antenna coil again. Supply.
[0032]
Thus, each antenna coil L1-L4 is cyclically switched one by one until a response from the non-contact IC card 2 is generated. In this embodiment, the first antenna coil L1, the second antenna coil L2, the third antenna coil L3, and the fourth antenna coil L4 are switched in this order, and the contactless IC card 2 can be switched to the fourth antenna coil L4. If no response from is generated, the switching from the first antenna coil L1 is repeated again.
[0033]
When a response from the non-contact IC card 2 is returned within the set time during selection of any one of the antenna coils (assumed to be the fourth antenna coil L4) (YES in step 1121), from the non-contact IC card 2 Is received by the radio circuit 52 via the fourth antenna coil L4 of the antenna device 100 and demodulated by the demodulation circuit. The response data demodulated by the radio circuit 52 is sent back to the host device 4 by the control circuit 51. When determining that the response data is normally acquired, the host device 4 performs subsequent communication processing (for example, authentication, data reading, data writing, etc.) (step 1123). 54 is switched to the antenna coil in the next switching order (the first antenna coil L1 in this example) (step 1124, step 1125), and the search for the antenna coil to be used for communication with the next non-contact IC card 2 Migrate to
[0034]
This operation is performed when a response from the non-contact IC card 2 is returned within the set time during the selection of the first antenna coil L1, the second antenna coil L2, or the third antenna coil L3 (step 1103, step 1109, Alternatively, YES in step 1115 is also performed.
[0035]
Note that the switching order of the antenna coils of the antenna device 100 is not limited to the examples of FIGS. 11 and 12.
[0036]
In the above embodiment, communication with the non-contact IC card 2 is performed using the antenna coil that can receive the response first in the process of sequentially switching the antenna coils L1 to L4. The control circuit 51 may measure the reception level when the coils L1 to L4 are used, and may determine the antenna coil when the maximum reception level is obtained. According to this configuration, the process of determining the antenna coil to be used in the wireless device 3 is performed, so that the burden on the host device 4 can be reduced.
[0037]
By the way, generally, when a plurality of antenna coils are overlapped, electromagnetic coupling occurs between the antenna coils, and the antenna resonance frequency varies due to variations in the inductance of the antenna coils. However, although the antenna device 100 according to the present invention has a configuration in which the four antenna coils L1-L4 are overlapped, the antenna coils L1-L4 are not coupled to each other. Hereinafter, the principle will be described.
[0038]
FIG. 13 shows the principle that the four antenna coils L1-L4 are not coupled.
[0039]
First, attention is paid to one antenna coil region L1A while the first antenna coil L1 is energized. The magnetic flux H1A generated in the antenna coil region L1A passes through the frame 11 indicated by the dotted line of the second antenna coil L2, but at this time, the magnetic flux generated in the antenna coil region L2A at one end of the second antenna coil L2 and the intermediate The amount of magnetic flux generated in the upper half region of the antenna coil region L2B (the magnetic flux density) is equal, and the direction of the magnetic flux is reversed. Therefore, since both magnetic fluxes cancel each other and are canceled, the coupling between the antenna coil region L1A of the first antenna coil L1 and the antenna coil regions L2A and L2B of the second antenna coil L2 does not occur.
[0040]
Similarly, when attention is paid to the other antenna coil region L1B of the first antenna coil L1, the magnetic flux H1B generated in the antenna coil region L1B is similar to the above principle in the antenna coil regions L2B and L2C of the second antenna coil L2. Therefore, the coupling between the antenna coil region L1B of the first antenna coil L1 and the antenna coil regions L2B and L2C of the second antenna coil L2 does not occur.
[0041]
As described above, no coupling occurs between the first antenna coil L1 and the second antenna coil L2.
[0042]
When the magnetic flux H1A generated in the antenna coil region L1A of the first antenna coil passes through the third antenna coil L3, the magnetic flux generated in the upper half region of one antenna coil region L3A of the third antenna coil L3. Since the magnetic flux generated in the upper half region of the other antenna coil region L3B has the same amount (magnetic flux density) and the direction of the magnetic flux is reversed, the antenna coil region of the first antenna coil L1 is also used. The coupling between L1A and the antenna coil regions L3A and L3B of the third antenna coil L3 does not occur.
[0043]
Similarly, when the magnetic flux H1A generated in the antenna coil region L1A of the first antenna coil L1 passes through the fourth antenna coil L4, the upper half of each antenna coil region L4A, L4C on both sides of the fourth antenna coil L4. The sum of the magnetic fluxes generated in each region and the magnetic flux generated in the upper half region of the intermediate antenna coil region L4B are equal in amount (magnetic flux density) and the direction of the magnetic flux is opposite. No coupling occurs between the antenna coil region L1A of the one antenna coil L1 and the antenna coil regions L4A, L4B, and L4C of the fourth antenna coil L3.
[0044]
Similarly, when attention is paid to the area of the other antenna coil area L1B of the first antenna coil L1, the operation is the same as described above, and thus the coupling between the first antenna coil L1 and the other antenna coils L2, L3, and L4 occurs. Will not.
[0045]
Since the above principle is the same when all antenna coils are viewed in the same manner, the electromagnetic coupling between the four antenna coils L1 to L4 does not occur as a result.
[0046]
The antenna device and non-contact IC card reader / writer device of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. .
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to stably perform communication with a non-contact IC card that is trapped in any direction with respect to the antenna surface.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an antenna device 100 according to an embodiment of the present invention.
2 is a diagram showing a configuration of a first antenna coil L1 in the antenna device 100. FIG.
3 is a diagram showing magnetic coupling between the first antenna coil L1 and the non-contact IC card 2 of FIG. 2;
4 is a diagram showing a configuration of a second antenna coil L2 in the antenna device 100. FIG.
5 is a diagram showing magnetic coupling between the second antenna coil L2 and the non-contact IC card 2 of FIG. 4;
6 is a diagram showing a configuration of a third antenna coil L3 in the antenna device 100. FIG.
7 is a diagram showing magnetic coupling between a third antenna coil L3 and a non-contact IC card 2. FIG.
8 is a diagram showing a configuration of a fourth antenna coil L4 in the antenna device 100. FIG.
9 is a diagram showing magnetic coupling between the fourth antenna coil L4 and the non-contact IC card 2. FIG.
FIG. 10 is a diagram showing a configuration of a non-contact type IC card reader / writer device 200 according to an embodiment of the present invention.
FIG. 11 is a flowchart showing a processing procedure when wireless communication with the non-contact IC card 2 is performed by switching each antenna coil L1, L2, L3, L4 of the antenna device.
FIG. 12 is a diagram showing the switching timing of each antenna coil L1, L2, L3, L4.
FIG. 13 is a diagram for explaining a principle that antenna coils L1, L2, L3, and L4 are not coupled.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Antenna support body, 2 ... Non-contact IC card, 3 ... Radio equipment, 4 ... Host device, 5 ... Control device, 51 ... Control circuit , 52... Radio circuit, 53... Tuning circuit, 54... Switching circuit, 100... Antenna device, L1. Antenna coil, L3... Third antenna coil, L4.

Claims (9)

It has two antenna coils, and each of these antenna coils is a loop antenna formed on a plane, and is composed of two loops so as to divide the total area of the loop antenna into two equal parts. Are formed so as to generate magnetic fluxes in opposite directions from the portions of the loops, and the two antenna coils are arranged in an insulated state so as to rotate approximately 90 degrees in a plane. An antenna device characterized by the above. A loop antenna formed on a plane, which is composed of two loops so as to divide the total area of the loop antenna into two equal parts, and magnetic fluxes that are opposite to each other are generated from each loop part by energization. A first antenna coil;
A second antenna coil disposed in an insulated state on the first antenna coil, the loop being formed by three loops arranged in a line on a plane, and the total area of the loop antenna of the first antenna coil as a whole In addition to having the same area, the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2 to 1, and the middle loop portion and the loop portions at both ends are energized by energization. An antenna device comprising: a second antenna coil that generates magnetic fluxes in opposite directions. A loop antenna formed on a plane, which is composed of two loops so as to divide the total area of the loop antenna into two equal parts, and magnetic fluxes that are opposite to each other are generated from each loop part by energization. A first antenna coil;
A second antenna coil disposed in an insulated state on the first antenna coil, the loop being formed by three loops arranged in a line on a plane, and the total area of the loop antenna of the first antenna coil as a whole In addition to having the same area, the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2 to 1, and the middle loop portion and the loop portions at both ends are energized by energization. A second antenna coil that generates magnetic fluxes in opposite directions;
A third antenna coil disposed in an insulating state in an orientation rotated about 90 degrees in a plane with respect to the first antenna coil and having the same loop shape as the first antenna coil. Antenna device to do. It has two antenna coils, and each of these antenna coils is a loop antenna formed on a plane, and is composed of two loops so as to divide the total area of the loop antenna into two equal parts. The antenna unit is formed so as to generate magnetic fluxes in opposite directions from each loop part, and the two antenna coils are arranged in an insulated state in an orientation rotated approximately 90 degrees in a plane. When,
A non-contact IC card reader / writer device comprising switching means for switching an antenna coil to be driven out of two antenna coils of the antenna unit. 5. The non-contact IC card reader / writer according to claim 4, further comprising a determination unit that sequentially switches antenna coils driven by the switching unit to determine an antenna coil used for communication with the non-contact IC card. apparatus. A loop antenna formed on a plane, which is composed of two loops so as to divide the total area of the loop antenna into two equal parts, and magnetic fluxes that are opposite to each other are generated from each loop part by energization. A first antenna coil and a second antenna coil disposed in an insulated state on the first antenna coil, wherein the first antenna coil is formed of three loops arranged in a line on a plane, The loop antenna has the same area as the total area of the loop antenna, and the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2 to 1, An antenna portion having a second antenna coil that generates magnetic fluxes in opposite directions from the loop portions at both ends;
A non-contact IC card reader / writer device comprising switching means for switching an antenna coil to be driven out of two antenna coils of the antenna unit. 7. The non-contact IC card reader / writer according to claim 6, further comprising determination means for sequentially switching antenna coils driven by the switching means to determine an antenna coil used for communication with the non-contact IC card. apparatus. A loop antenna formed on a plane, which is composed of two loops so as to divide the total area of the loop antenna into two equal parts, and magnetic fluxes that are opposite to each other are generated from each loop part by energization. A first antenna coil and a second antenna coil disposed in an insulated state on the first antenna coil, wherein the first antenna coil is formed of three loops arranged in a line on a plane, The loop antenna has the same area as the total area of the loop antenna, and the area ratio between the middle loop portion of the three loops and the individual loop portions on both sides is set to 2 to 1, A second antenna coil that generates magnetic fluxes in opposite directions from the loop portions at both ends, and insulative state rotated approximately 90 degrees in a plane relative to the first antenna coil Are arranged to overlap, the antenna portion and a third antenna coil having the same loop-shaped and the first antenna coil,
A non-contact IC card reader / writer device comprising switching means for switching an antenna coil to be driven among the antenna coils of the antenna section. 9. The non-contact IC card reader / writer according to claim 8, further comprising determination means for sequentially switching antenna coils driven by the switching means to determine an antenna coil used for communication with the non-contact IC card. apparatus.

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