Data communication apparatus

TITLE OF THE INVENTION

Data Communication Apparatus

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to a data communication apparatus for non-contact data communication exploiting electromagnetic induction.

Description of Related Art

Recently, in the field of automatic ticket checkers or electronic money systems, a non-contact IC card is in use. This non-contact IC card includes, within the bulk of the card, an IC (integrated circuit) chip, composed of various electronic circuits, adapted for performing various processing operations for data write/readout, and a loop coil antenna, composed of a conductor wound in a flat configuration. The non-contact IC card exploits the; a.c. voltage, induced in a loop coil antenna provided to the non-contact IC card, under an a.c. magnetic field of, for example, 13.56 MHz, generated in the loop coil antenna provided to a reader/writer adapted to write or read out data for the non-contact IC card, on the basis of the principle of electromagnetic induction, as a power supply for actuating an IC chip. Moreover, the non-contact IC card has non-contact data communication with the reader/writer by changing the load impedance.

Thus, with the present non-contact IC card, in which the power as needed is supplied from the reader/writer, there is no necessity of providing an internal power supply, such that the data write/readout operation may be carried out with ease speedily, simply by momentarily holding the card over the reader/writer.

Meanwhile, in view of user-friendliness of the non-contact IC card, it is now being contemplated to have the above-described non-contact IC card mounted on e.g. a portable device, such as a cellular phone, so that the portable device itself may serve as the non-contact device for wireless near-distance transmission, without the necessity for a user to carry about the card, as disclosed in the Japanese laid-Open Patent publication 11-213111.

However, if, with the above-described data communication apparatus, the planar loop coil antenna 101, mounted on the non-contact IC card, is arranged in an enclosure 100 of a veritable thickness, such as the cellular phone schematically shown in Fig.7, sensitivity offset occurs across one of the major surfaces of the enclosure 100, in which the loop coil antenna 101 is arranged, and the other major surface, thus deteriorating the user friendliness. That is, if the planar loop coil antenna 101 is arranged within the inside of the enclosure 100, having the veritable thickness, such a problem is raised in which the sensitivity of the loop coil antenna

101 is changed with the orientation or the sensitivity area becomes smaller in size.

Thus, for equalizing the sensitivity of the loop coil antenna 101 across both major surfaces of the loop coil antenna 101, the planar loop coil antenna 101 must be arranged centrally in the enclosure 100, However, if, with the portable device, such as the aforementioned cellular phone, this planar loop coil antenna is arranged centrally in the enclosure, there is imposed significant mounting constraint.

Moreover, if, with the above-described loop coil antenna 101, the number of turns of the conductor Is increased, the opening area of the loop coil antenna is decreased, thus narrowing down the area of sensitivity of communication with the reader/writer.

Thus, for equalizing the sensitivity of the loop coil antenna 101 across both major surfaces of the loop coil antenna 101, the planar loop coil antenna 101 must be arranged centrally in the enclosure 100. However, if, with the portable device, such as the aforementioned cellular phone, this planttr loop coil antenna is arranged centrally in the enclosure, there is imposed significant mounting constraint.

Moreover, if, with the above-described loop coil antenna 101, the number of turns of the conductor is increased, the opening area of the loop coil antenna is decreased, thus narrowing down the area of sensitivity of communication with the reader/writer.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a data communication apparatus whereby it is possible to resolve the aforementioned problems inherent in the prior art.

It is another object of the present invention to provide a non-contact data communication apparatus in which the sensitivity of the loop coil antenna is equalized on both major surfaces of the enclosure, regardless of the thickness of the enclosure, and in which it is possible to enlarge the sensitivity area.

A data communication apparatus according to the present invention includes an enclosure, a mobile phone function unit arranged within said enclosure, a loop coil antenna arranged so that at least a portion of a conductor extends along lateral surfaces, which are surfaces forming said enclosure with the exclusion of both major surfaces of the enclosure, and a semiconductor integrated circuit connected to said loop coil antenna, said semiconductor integrated circuit carrying out non-contact data communication over said loop coil antenna with an exterior communication device with use of electromagnetic induction, and having the function of a noncontact IC card and/or a reader/writer function.

With the data communication apparatus, described above, in which the loop coil antenna is arranged with its conductor extending along the lateral side of the enclosure, the sensitivity of the loop coil antenna may be equalized in a direction along the thickness of the enclosure, thereby enlarging the area of communication sensitivity of the loop coil antenna.

Other objects and specified advantages of the present invention will become more apparent from the following explanation especially when read in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.l is a schematic perspective view showing the structure of a cellular phone embodying the present invention.

Fig.2 is a block diagram showing the structure of a semiconductor integrated circuit built into the cellular phone.

Fig.3 is a perspective view showing the structure of a loop coil antenna 15 arranged in the cellular phone.

Fig.4 is a plan view showing the structure of ihe loop coil antenna and a flexible printed circuit board.

Fig.5 is a perspective view showing the state in which the loop coil antenna is formed by the flexible printed circuit board.

Fig.6 is a perspective view showing a modified structure of a loop coil antenna arranged in the cellular phone.

Fig.7 is a perspective view showing the structure of a conventional loop coil antenna.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, a data communication apparatus according to the present invention is explained in detail.

The data communication apparatus, embodying the present invention, is a cellular phone 1, having a non-contact IC card function and a reader/writer function, in addition to the conventional phone function, as shown for example in Fig.l. This cellular phone 1 is of such a structure having a display part 3 mounted for opening/closure to a main body part 2.

Referring to Figs.l and 2, a semiconductor integrated circuit 4 (IC), having a non-contact IC card function and a reader/writer function, a loop coil antenna 5 on ¹⁵ the non-contact card side, and a loop coil antenna 6 oil the reader/writer side, are built in the cellular phone 1. The loop coil antennas 5. 6 are electrically connected to the semiconductor integrated circuit 4. Of these, the loop coil antenna 5 of the non-contact card side is arranged in an enclosure of the main body part 2, while the loop coil antenna 6 of the reader/writer side is arranged in an enclosure of the display part 3.

The semiconductor integrated circuit 4 includes a non-contact IC card 7, for which data is written and read out by an exterior reader/writer, not shown, a reader/writer transmitting circuit 8 for writing data on an exterior non-contact IC card, and a reader/writer receiving circuit 9 for reading out data from the exterior non-contact IC card. To this semiconductor integrated circuit 4, there is also ⁵ electrically connected a cellular phone function unit 20 for implementing the call or communication function of the cellular phone 1.

On receipt of an electromagnetic wave, as a query signal, sent out via loop coil antenna 6 on the reader/writer side, over the loop coil antenna 5, the non-contact IC card 7 rectifies the carrier of the electromagnetic wave to convert it ¹⁰ into a d.c. supply power, which drives an internal circuit, not shown. The non-contact IC card 7 also executes amplitude modulation, as the IC card changes the load between it and the exterior reader/writer side loop coil antenna, responsive to the query signal, to send a reply signal through the loop coil antenna 6 to the exterior reader/writer.

¹⁵ The reader/writer transmitting circuit 8 modulates the carrier for transmission, responsive to data for transmission, to send the query signal through the loop coil antenna 6 to the non-contact IC card. The reader/writer receiving circuit 9 receives a reply signal, sent from the exterior non-contact IC card, over the loop coil antenna 6, and demodulates the signal to acquire received data.

The non-contact IC card side loop coil antenna 5 is arranged so that its conductor 5a extends along the entire inner peripheral surface of an enclosure 2a of r\

Ob 'X the main body part 2, as shown in Figs.l and 3. This enables the sensitivity of the loop coil antenna 5 to be equalized along the thicknes s of the enclosure 2a, without dependency on the thickness of the enclosure 2a.

This loop coil antenna 5 has a three-dimensional shape by the conductor 5a being wound spirally along the inner lateral surface of the enclosure 2a. In this case, a large opening area of the loop coil antenna 5 may be provided without dependency on the number of turns of the winding of the conductor 5a, thus appreciably enlarging the area of sensitivity for communication with the reader/writer, as compared to a conventional loop coil antenna 101 shown in Fig.7.

¹⁰ The loop coil antenna 5, having this three-dimensional shape, may readily be produced using a flexible printed circuit board shown in Fig.4. Specifically, the flexible printed circuit board 10 is a flexible elongated insulating substrate or film of, for example, polyimide. The conductor 5a is formed on the major surface of the flexible printed circuit board 10 as a plural number of linear copper foil patterns ¹⁵ arrayed in a direction perpendicular to the longitudinal direction of the substrate. This flexible printed circuit board 10 includes plural folding lines 10a in keeping with the comers of the inner lateral surface of the enc losure 2a. The forming positions of the folding lines 10a are optional.

This flexible printed circuit board 10 is bent along the folding lines 10a in the same direction and the longitudinal ends thereof are bonded together to form the flexible printed circuit board 10 in a tubular form. At this time, the one and the

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J’.'N T;/ other ends of the neighboring patterns of the conductor 5a are severally interconnected to form a sole loop coil of the conductor wound spirally along the short side direction of the flexible printed circuit board 10. It is noted that both ends of the loop coil are electrically connected to the s emiconductor integrated circuit 4 mounted on the flexible printed circuit board 10. The ends of the loop coil may also be connected to a substrate on which the semiconductor integrated circuit 4 is mounted e.g. by a wire.

The loop coil antenna 5, having the three-dimensional shape, may be produced extremely readily. This loop coil antenna 5 may readily be arranged along the lateral surface of the enclosure 2a. The loop coil antenna 5 is bonded to the lateral surface of the enclosure 2a using an adhesive or by plugging into a socket-like recess formed in the lateral surface of the enclosure 2a. The loop coil antenna 5 may also be secured by any other suitable methods as necessary.

Meanwhile, the loop coil antenna 5 may also be arranged so that, instead of ¹⁵ the conductor 5a being arranged on the entire periphe:-y of the enclosure 2a, the conductor 5 a is laid along a fraction of the lateral surf ace of the enclosure 2a, as shown for example in Fig.6a.

The loop coil antenna 5 may be directly embedded in the lateral surface of the enclosure 2a of resin. Alternatively, the conductor' 5 a may be plated on the lateral surface of the resin enclosure 2a, to a preset pattern, or the conductor 5a may be arranged in a groove formed in the lateral surface of the enclosure 2a.

In the cellular phone 1, described above, in which the non-contact IC card side loop coil antenna 5 is arranged for extending along the lateral surface of the enclosure 2a of the main body part 2, it is possible to provide for approximately equalized sensitivity of the loop coil antenna 5 along the thickness of the enclosure

2a on both major surfaces of the main body part 2 to enlarge the sensitivity area of communication of the cellular phone 1 with the exterior reader/writer. Thus, with the present cellular phone 1, it is possible to obtain the sensitivity of the loop coil antenna 5 which is substantially equalized across both major surfaces of the main body part 2, so that the sensitivity area for communication may be enlarged to ¹⁰ improve user friendliness further.

With the cellular phone 1, described above, the conductor provided to the reader/writer side loop coil antenna 6 may also be of a three-dimensional shape, that is, may be arranged so that its conductor 5a extends along the lateral surface of the enclosure of the display part 3, as in the case of the non-contact IC card side loop ¹⁵ coil antenna 5. Additionally, with the cellular phone 1, the non-contact IC card side loop coil antenna 5and the reader/writer side loop coil antenna 6 may be provided to the enclosure of the display part 3 and to the enclosure 2a of the main body part 2, respectively. Furthermore, with the cellular phone 1, both of the loop coil antennas 5, 6 may be provided to the enclosure of the main body part 2 or to the enclosure of the display part 3.

The data communication apparatus of the present invention is not limited to ' 4 i

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the cellular phone 1 and may be broadly applied to a non-contact device for wireless near-distance transmission carrying the aforementioned IC card function and/or the reader/writer function.

It should be noted that the present invention is not limited to the above ⁵ embodiment described in the foregoing with reference to the drawings and, as may be apparent to those skilled in the art, various changes, substitutions or equivalents may be envisaged without departing from the scope of the invention.

Industrial Utilizability

With the data communication apparatus, according to the present invention, 10 it is possible to obtain substantially equalized sensitivity of the loop coil antenna on both major surfaces of the enclosure having a veritable thickness, such that the sensitivity area which allows for communication may be enlarged, thus further improving the user friendliness.