JPH05314330A - Attaching device for noncontact ic card - Google Patents

Abstract

PURPOSE:To reduce an influence of a window glass upon the characteristic of an antenna at the time of setting a noncontact IC card to the inside of the window glass of a vehicle. CONSTITUTION:A part, which is placed between a front glass 4 of the vehicle and an antenna 2, of a device 10 which attaches a noncontact IC card 1 to an inside 4a of the front glass 4 is made of a dielectric member 11, and the dielectric constant and the thickness of the dielectric member 11 are set to match the impedance of the front glass 4 to that of the antenna 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for attaching a non-contact IC card used in a non-stop and cashless toll collection system for toll roads to a window glass of a vehicle without deteriorating antenna characteristics.

[0002]

2. Description of the Related Art Conventionally, in toll collection systems for toll roads, there is a system in which a tollgate collector collects cash directly from a driver, or a system in which a driver puts cash into an automatic machine to automatically collect the toll. Has been adopted. For this reason,
Drivers need to stop at the toll booth or prepare cash.

On the other hand, at present, as a toll collection system in the near future, non-stop cashless systems using non-contact IC cards have been developed all over the world.

A charge collection system using a non-contact IC card (hereinafter, simply referred to as an IC card) will be described with reference to FIGS. 4 to 7.

FIG. 4 shows the appearance of an IC card, in which a planar antenna 2 in the microwave band is arranged on the surface of the IC card 1. As shown in FIG. 5, this IC card 1 is attached to the inside of a window glass of a vehicle 3, for example, a windshield 4, with its antenna surface facing. Information such as an ID number unique to each vehicle is stored in the memory of the IC card 1.

FIG. 6 shows an outline of a toll collection system, in which a tollgate 5 is provided for a vehicle 3 having the IC card 1 described above.
A ground station 7 having an antenna 6 is arranged in the vicinity of the ground station 7, the ground station 7 is connected to a terminal computer 8 in the tollgate 5, and the terminal computer 8 is connected to a host computer 9. With such a system configuration, when the vehicle 3 having the IC card 1 passes in front of the ground station 7, the ID number and the traffic pass between the ground station 7 and the IC card 1 via the antennas 2 and 6. Information such as charges is automatically wirelessly communicated by microwaves. After the information is recognized by the ground station 7, it is transmitted to the terminal computer 8 and stored in the memory there, and further transmitted from the terminal computer 8 to the host computer 9, and the bank where the passing vehicle 3 is registered. Toll charges will be cleared automatically from your account.

[0007]

Since the antenna 2 of the IC card 1 has the windshield 4 on its front surface,
The influence of the glass deteriorates the antenna characteristics as compared with the case of a single IC card. FIG. 7 shows the influence of glass on the circularly polarized wave type antenna 2, and the transmittance and the axial ratio of the radio wave transmitted and received by the antenna 2 greatly change depending on the relationship between the wavelength λ of the radio wave and the glass thickness. This is meaningless even if the antenna 2 is matched to the impedance of the air, and means that the antenna 2 must be designed, manufactured and adjusted including the glass thickness. Therefore, in consideration of the fact that the glass thickness often differs depending on the vehicle type, it is necessary to produce various types of IC cards 1, and the production equipment including human ones becomes extremely large. Further, if the adjustment is performed with the glass included, when the IC card for a certain vehicle type is detached from the vehicle and used alone or in another vehicle type, the antenna characteristics change.

In addition to the circular polarization type, a linear polarization type antenna 2 is also used. This is likely to cause fading due to reflected waves, but the influence of glass is relatively small. However, since the degree of influence of glass is not zero, if the glass thickness varies depending on the vehicle model, the antenna characteristics will still change.

In view of the above-mentioned prior art, the present invention is a non-contact type I.
An object of the present invention is to provide a device in which a C card can be mounted inside a window glass of a vehicle without deteriorating antenna characteristics.

[0010]

According to the present invention, there is provided a non-contact IC card mounting device, comprising a dielectric member and a card holder for removably holding the non-contact IC card with the antenna surface facing the dielectric member. And a mounting member for mounting the dielectric member and the card holding member to the vehicle with the dielectric member facing the inner surface of the window glass of the vehicle, the dielectric member matching the impedance of the window glass with the impedance of the antenna. It is characterized by having a dielectric constant and a thickness.

[0011]

The dielectric member is inserted between the front surface of the antenna and the window glass to reduce the influence of the window glass on the antenna. As a result, the antenna can be designed, manufactured and adjusted according to, for example, the impedance of air without considering the window glass. Therefore, non-contact IC including antenna
Labor saving of processes and equipment such as card production. In addition, stable wireless communication can be ensured by using the circularly polarized antenna. Further, since the antenna characteristics are almost the same when the non-contact IC card is used alone and when it is mounted on the vehicle, not only the toll fee is paid for the non-contact IC card, but also it is charged when the card is removed from the vehicle. It can be used for cashless payment for shopping, etc. by bringing it to the service area of the road and wireless communication with the ground station installed there, and the application of the contactless IC card spreads.

If the antenna of the non-contact IC card is made constant by adjusting it to the impedance of the air, a mounting device having a different dielectric member will be used for each thickness of the window glass of the vehicle. As compared with the case where various types of antennas are manufactured according to the window glass, the equipment and cost are low and advantageous.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a mounting device 10 for a non-contact IC card. As shown in FIG. 1A, this mounting device 10 has a plate-shaped dielectric member 11 made of plastic or the like and a space on the back surface of the dielectric member 11. A card holding member 13 connected by opening 12 and a mounting member 14 formed on the front surface of the dielectric member 11 by a thin film of an adhesive material, for example. The front surface of the dielectric member 11 is closely attached to the inner side 4a of the windshield 4 of the vehicle. And pasted. The space 12 is dimensioned so that a non-contact IC card (hereinafter, also simply referred to as an IC card) can be inserted from the side. The card holding member 13 has elasticity, and the IC card inserted in the space 12 is elastically pressed by the back portion 13a to be held in close contact with the dielectric member 11 to prevent the IC card from moving or coming off. .. The IC card 1 is shown in FIG.
Shows a state in which the front surface of the planar antenna 2 is inserted into the space 12 with the front surface facing the dielectric member 11.

Here, the antenna 2 of the IC card 1 is a circular polarization type planar antenna which is matched to the specific impedance Zo of air (Zo = 120π≈377 ohm). Therefore, as shown in the equivalent circuit of FIG.
When the C card 1 is used after being removed from the vehicle, the radiation impedance Zout seen from the antenna 2 is Zout = Zo, and matches the air 15.

On the other hand, the IC card 1 is attached to the mounting device 10
When attached to the antenna, the radiation impedance Zout seen from the antenna 2 is as shown in the equivalent circuit of FIG.
It is expressed by the following equation (1). Zout = Zo + Zg + Zd (1) where Zo: impedance of the air 15 Zg: impedance of the windshield 4 Zd: impedance of the dielectric member 11

Therefore, the impedance Z of the dielectric member 11
Since d is a function of its relative permittivity ε _r and thickness t, ε _r
By adjusting t and t to appropriate values, the following equation (2) is obtained. Zo + Zg + Zd = Zo (2)

By defining ε _r and t as described above,
The radiation impedance Zout seen from the antenna 2 is the air 1
5 and the impedance Zo of the antenna 2, which is equivalent to the case shown in FIG. 2A without being affected by the glass 4.

An example of wireless communication between the IC card and the ground station will be described with reference to FIG. In FIG. 3, first, the local oscillator 21 of the ground station 7 to the amplifier 2
2, unmodulated microwave (hereinafter, CW (Continuous Wav) via the power divider 23 and the transmission antenna 6a.
e). ) 31 is transmitted to the IC card 1. This C
W31 is a receiving antenna 2 arranged on the IC card 1.
The information is received by a and is modulated by the modulator 18 by the information such as the ID number registered in the RAM (memory) 17 and then returned from the transmitting antenna 2b to the ground station 7. 16 is CP
U. At the ground station 7, the modulated wave 32 from the IC card 1
Is received by the receiving antenna 6b, and homodyne detection using the local oscillation signal from the power divider 23 is performed by the mixer 24 to demodulate information such as the ID number of the IC card 1. The demodulated signal has a noise component removed by the BPF 25, is amplified by the IF amplifier 26 to an appropriate size, is waveform-shaped by the comparator 27, and is sent to the terminal computer 8 as a digital signal.

[0019]

As described above on the basis of the embodiments, according to the present invention, the dielectric member of the mounting device is inserted between the window glass of the vehicle and the antenna of the non-contact IC card, and the window for the antenna is formed. Reduce the effect of glass. As a result, the antenna can be designed, manufactured and adjusted according to, for example, the impedance of air without considering the window glass. Therefore, it is possible to save labor in the process and equipment such as non-contact IC card production including the antenna. In addition, stable wireless communication can be ensured by using the circularly polarized antenna. Further, since the antenna characteristics are almost the same when the non-contact IC card is used alone and when it is mounted on the vehicle, not only the toll fee is paid for the non-contact IC card, but also it is charged when the card is removed from the vehicle. It can be used for cashless payment for shopping, etc. by bringing it to the service area of the road and wireless communication with the ground station installed there, and the application of the contactless IC card spreads.

[Brief description of drawings]

FIG. 1 is a sectional view of a non-contact IC card mounting device according to an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram for explaining the principle of reducing the influence of glass.

FIG. 3 is a block diagram showing an example of wireless communication between a non-contact IC card and a ground station.

FIG. 4 is an external view showing an example of a non-contact IC card.

FIG. 5 is a diagram showing a state in which a conventional non-contact IC card is attached to a vehicle.

FIG. 6 is a conceptual diagram showing a fee collection system using a contactless IC card.

FIG. 7 is a characteristic diagram for explaining the influence of the window glass on the antenna.

[Explanation of symbols]

 1 Non-contact IC card 2 Antenna 3 Vehicle 4 Windshield 10 Mounting device 11 Dielectric member 12 Space 13 Card holding member 14 Mounting member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // G07B 15/00 N 8111-3E

Claims (1)

[Claims] 1. A dielectric member, a card holding member that detachably holds a non-contact IC card with the antenna surface facing the dielectric member, and a state in which the dielectric member faces the inner surface of a window glass of a vehicle. And a mounting member for mounting the card holding member on the vehicle, the dielectric member having a permittivity and a thickness for matching the impedance of the window glass with the impedance of the antenna.
C card mounting device.