JP4949333B2 - Reading / writing device and portable device - Google Patents

Description

  The present invention relates to a read / write device and a portable device. In particular, a read / write device (reader / writer) for reading / writing recorded contents of a portable recording medium such as a non-contact IC card and an RF (Radio Frequency) tag, and a portable device that carries the read / write device and processes and communicates various information. The present invention can be suitably applied to devices (such as information processing devices and information communication devices).

  As a read / write device for reading / writing recorded contents of a portable recording medium such as a non-contact IC card or an RF tag, Japanese Patent Laid-Open No. 2001-229347 “Reader / Writer” and Japanese Patent Laid-Open No. 2003-256679 “Contactless” are disclosed. As described in “Antenna Sheet for Media and Reader / Writer System”, technologies for ensuring installation flexibility by mounting antenna coils on a flexible substrate have been disclosed. However, it has not yet been realized to be downsized to such an extent that it can be incorporated into a portable device.

  Specifically, the antenna coil and the control circuit of the read / write device (reader / writer) are each mounted on separate substrates, and also for connecting to a host device (information processing device, information communication device, etc.) Since the storage location of the connection cable in the read / write device (reader / writer) is also a separate configuration, the occupied size is increased, and not only the flexibility of installation but also the incorporation into portable devices where further miniaturization is essential Is in a difficult situation.

  Further, as a read / write device (reader / writer) that attempts to achieve downsizing to such an extent that it can be incorporated into a portable device, the present inventors of Non-Patent Document 1 “Multi-interface ultra-compact suitable for incorporation into a portable device”. There is a technique described in "Reader / Writer" (The Institute of Electronics, Information and Communication Engineers, IEICE Technical Report USN 2007-64 (2008-01), pp. 55-60). However, even in the technology described in Non-Patent Document 1, the mounting substrate of the antenna coil portion and the control circuit is premised on a separate type, so that it is sufficient for portable devices that are increasingly pursued to be miniaturized. It has not yet reached a size that allows it to be mounted on a vehicle.

Under the circumstances as described above, there is a strong demand for realizing an ultra-small read / write device (reader / writer) that has both the “integration of an antenna circuit and a control circuit” and “installation flexibility”.
JP 2001-229347 A JP 2003-256777 A Hideo Yamamoto, Minoru Ikeda, Yasuhiro Hosoda; “Multi-interface ultra-compact reader / writer suitable for incorporation into portable devices”, IEICE, IEICE Technical Report USN 2007-64 (2008-01), pp55-60

  In the conventional technology, as described above, the antenna coil and the control circuit of the read / write device (reader / writer) are mounted on different substrates, respectively, and the read / write device and the host device (information processing device) For example, a place for storing a connection cable for connecting a portable device such as an information communication device in a read / write device is prepared separately, so that the entire read / write device can be housed in a portable device that is becoming smaller and lighter. Therefore, there is a problem that it is impossible to reduce the size until it can be easily achieved.

  The present invention has been made in view of such circumstances, and provides a read / write device that has both flexibility and miniaturization that can be sufficiently mounted on a portable device, and further includes the read / write device. The object is to provide a portable device that can be functionalized.

  In order to solve the above-mentioned problems, the present invention takes into account the incorporation of a read / write device (reader / writer) for reading and writing recorded contents of a portable recording medium in a narrow space in the portable device, and the curved surface on the inner surface of the portable device. In the conventional technology, the antenna coil and the control circuit constituting the read / write device are mounted on a flexible substrate, and in the conventional technology, two antenna substrates and a control circuit substrate are mounted. What is configured separately on the board is mounted on a single board, and the connection cable for connecting to the host device is also connected to the antenna coil by utilizing the plasticity of the flexible board. A flexible board on which the control circuit is mounted is extended by a predetermined length and has a host device connection terminal for connection to the host device. By utilizing as that connecting cable, it is characterized in that it downsized.

  At this time, the antenna coil and the control circuit are mounted and integrated on a single flexible substrate so that the magnetic field generated by the antenna coil is prevented from being adversely affected by the ground plane (ground plane) of the control circuit. In addition, the control circuit should be intensively installed in the vicinity of the position corresponding to the central axis of the antenna coil where the magnetic field intensity inside the antenna coil is the weakest, and the control circuit should match the central axis of the antenna coil as the ground pattern of the ground plane. A plurality of notches are formed radially from the center of the ground surface to suppress eddy currents.

  Specifically, the present invention comprises the following technical means.

According to a first technical means, in a read / write device for reading / writing recorded contents of a portable recording medium, an antenna coil electromagnetically coupled to the portable recording medium on a single flexible substrate having a plurality of levels of plasticity, the antenna control circuit via a coil for reading and writing operations of data to and from the portable recording medium, and to implement a connection means for electrically connecting to a host device for controlling the operation of the control circuit, further, the control A ground plane for providing a ground potential of the circuit is formed on any one of the layers of the flexible substrate so as to cover an arrangement region of the control circuit, with a position coincident with a center axis of the antenna coil as a center; and A plurality of notches are formed radially from the center of the ground surface toward the outer peripheral side .

In the read / write device described in the first technical means, a second technical means includes an oscillation circuit that oscillates at a predetermined frequency as the control circuit, an antenna circuit that connects the antenna coil and performs at least impedance matching , It includes at least a modulation / demodulation circuit for modulating / demodulating data read / written to / from the portable recording medium.

A third technical means is the reading and writing apparatus according to the first or second technical means, prior Symbol antenna coil is divided into at least two levels or more of a plurality of hierarchies of the flexible substrate formed of a plurality of layers Each antenna coil arranged and divided into a plurality of layers is connected by a through hole.

  A fourth technical means is the read / write device according to the third technical means, wherein when the antenna coils arranged in a plurality of layers are connected to each other, the winding of the antenna coil of the younger-numbered layer is performed. It is characterized in that the end and the winding start of the antenna coil on the old side are sequentially connected.

  According to a fifth technical means, in the read / write device according to the third or fourth technical means, each of the antenna coils arranged in a plurality of layers is centered on the same central axis, respectively. It is characterized by being wound in the same direction along the outer circumference of each layer.

  According to a sixth technical means, in the read / write device according to the fifth technical means, the control circuit mounted on the flexible substrate is concentrated in the vicinity of a position coinciding with the central axis of the antenna coil. It is characterized by that.

A seventh technical means is the read / write device according to any one of the first to sixth technical means, wherein the number of the cuts increases as it approaches the outer peripheral side of the layer on which the ground surface is formed, and / Or a shape in which the width of the cut becomes wider as it is closer to the outer peripheral side of the layer on which the ground plane is formed, and / or a shape in which any of the cuts does not reach the center of the ground plane. Features.

According to an eighth technical means, in the read / write device according to any one of the first to seventh technical means, the connection means that is electrically connected to the host device is on any level of the flexible substrate. A connection cable having a terminal for connecting a host device for connecting to the host device is formed by extending the hierarchy by a predetermined length, and the connection cable is connected to the host device. It extends to the center of the hierarchy and is connected to the connection terminal of the control circuit by a through hole.

According to a ninth technical means, in the read / write device according to any one of the second to eighth technical means, the oscillation circuit includes an oscillator of either a crystal oscillator or a MEMS (micro electromechanical element) oscillator. And a voltage conversion circuit for converting a power supply voltage fed from the host device into an operating voltage of the oscillator.

A tenth technical means is the read / write device according to any one of the second to ninth technical means, wherein the antenna coil includes a first antenna element and a second antenna element, and the antenna coil is connected to the antenna coil. An antenna circuit connects one end of the first antenna element to the first antenna connection end of the modulation / demodulation circuit via a first capacitor, and connects to the ground via a third capacitor, and One end of the two antenna elements is connected to the second antenna connection end of the modulation / demodulation circuit via a second capacitor, and is connected to the ground via a fourth capacitor, and the other end of the first antenna element And the other end of the second antenna element is connected to the ground, and the connection point between the first capacitor and the third capacitor is the portable recording Characterized in that it is constructed by connecting the receiving end of the modem circuit for receiving a received signal from the body.

An eleventh technical means is the read / write device according to the tenth technical means, wherein the inductances of the first antenna element and the second antenna element are equal to each other, and the first capacitor and the second capacitor are , And the third capacitor and the fourth capacitor have the same capacitance.

A twelfth technical means is the read / write device according to the eleventh technical means, wherein a carrier frequency of a signal transmitted to and received from the portable recording medium is 13.56 MHz, and the first antenna element The second antenna element has an inductance of 1.0 μH, and the first capacitor and the second capacitor are a fixed capacitor having a capacitance of 22 pF or a variable capacitor including a capacitance of 22 pF within a variable range. In addition, the third capacitor and the fourth capacitor may be a fixed capacitor having a capacitance of 68 pF or a variable capacitor having a capacitance of 68 pF within a variable range.

A thirteenth technical means is the read / write device according to any one of the first to twelfth technical means, wherein each component constituting the control circuit is disposed only on one surface of the flexible substrate, The attachment means capable of attaching the read / write device to the inner wall surface of the host device is formed on the other surface of the flexible substrate.

A fourteenth technical means comprises a read / write device for reading / writing recorded contents of a portable recording medium, and in a portable portable device for performing various information processing and information communication, the read / write device is the first to thirteenth technologies. The reading / writing device according to any one of the means is used.

A fifteenth technical means is the portable device according to the fourteenth technical means, wherein the portable device is at least one of a mobile phone, a PHS terminal, a PDA (personal digital assistant), a portable music player, and a portable notebook PC. It is characterized by including.

  According to the read / write device and the portable device of the present invention, the antenna coil and the control circuit of the read / write device are integrated and mounted on a single flexible substrate, and the connection cable for connecting to the host device also includes the flexible substrate. Since the configuration used is used, it is possible to ensure flexibility in mounting the read / write device and to further reduce the size, and to be mounted on an ultra-small portable device that fits in the palm of the hand. In addition, it is possible to mount the read / write device in accordance with the shape inside the narrow housing of the mobile device, and there is an effect that it is possible to realize a mobile device that can be multifunctional.

  Furthermore, the control circuit of the read / write device is concentrated in the vicinity of the position corresponding to the central axis where the magnetic field intensity inside the antenna coil is the weakest, and as a ground pattern for the ground of the control circuit, As a structure that suppresses eddy current by forming a plurality of notches radially from the center position of the ground plane (position that coincides with the central axis of the antenna coil) arranged to cover the arrangement range of the control circuit Therefore, a portable recording medium that can obtain a large magnetic field strength as a magnetic field generated by the antenna coil of the read / write device and consumes a large amount of power even in an ultra-small read / write device mounted on a small portable device. Even when the recorded contents are read and written, the recorded contents of the portable recording medium can be reliably read and written.

  Hereinafter, an example of the best embodiment of the read / write device (reader / writer) and portable device according to the present invention will be described in detail with reference to the drawings. The read / write device according to the present invention is a device for reading / writing recorded contents of a portable recording medium such as a non-contact IC card or an RF (Radio Frequency) tag, while the portable device according to the present invention is connected to the read / write device. Is a portable information processing device / information communication device that incorporates the read / write device and performs various types of information processing and information communication, including a mobile phone, PHS (Personal Handy-Phone System) ) The reading / writing device such as a terminal, a PDA (Personal Digital Assistants), a portable music player, a portable notebook PC (Personal Computer), etc. can be accommodated to use the recorded contents of the portable recording medium. As long as it is a thing, it may be in any form.

(Features of the present invention)
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. In the read / write device (reader / writer) according to the present invention, an antenna coil is arranged along the outer periphery of one flexible substrate having plasticity, and a control circuit is provided in the vicinity of a position coincident with the central axis inside the antenna coil. As a ground pattern of a ground plane formed so as to cover the entire area where the control circuit is arranged (preferably, the center of the control circuit coincides with the central axis of the antenna coil). The eddy current generated by the magnetic field generated by the antenna coil is suppressed by forming a plurality of cuts radially from the center position of the ground plane corresponding to the position corresponding to the center axis of the antenna coil toward the outer periphery. The main feature is to suppress adverse effects on the magnetic field generated by the antenna coil.

  Thus, it is possible to obtain flexibility in mounting the read / write device by using a flexible substrate, and to reduce the size of the read / write device by integrating the mounting substrate of the antenna coil and the control circuit. At the same time, it is possible to easily mount a read / write device on a portable device whose functions are diversifying, and to improve the added value (multifunctionality) of the portable device.

(Configuration example of read / write device according to the present invention)
As a configuration example of the read / write device according to the present invention, FIG. 1 shows an implementation of each component constituting the read / write device. In the schematic diagram of FIG. 1, FIG. 1A shows the front surface of the flexible substrate 1 that is a mounting substrate of the read / write device, and FIG. 1B shows the back surface of the flexible substrate 1.

  As shown in FIG. 1A, the read / write device of this embodiment includes an antenna coil 2 that reads and writes information by electromagnetic coupling with a portable recording medium on a flexible substrate 1 having plasticity, and an antenna. A control circuit 3 that performs a data read / write operation with a portable recording medium via the coil 2 is mounted, and a portable device that is an example of a host device that controls the operation of the control circuit 3 of the read / write device. As a connection means for electrical connection, a connection cable 4 provided at one end with a host device connection terminal 5 for connecting to the host device is extended to a predetermined appropriate length of the flexible substrate 1. Equipped in the form.

  The flexible substrate 1 is formed by laminating materials such as a polyimide film, a photo solder resist film, and a liquid crystal polymer rich in plasticity in two or more layers, and is configured as an n-layer (n ≧ 2) multilayer substrate. Is done. From the viewpoint of plasticity, it goes without saying that the copper foil used for wiring between the components mounted on the flexible substrate 1 is also a material rich in plasticity.

  As shown in FIG. 2, the antenna coil 2 is arranged in a plurality of layers (in the case of FIG. 2, the first layer 11, the second layer 12,..., The nth layer 1n) of at least two layers. It is divided and arranged. In addition, antenna coils of each layer arranged by being divided into a plurality of layers are connected to each other through the respective through holes 10. Furthermore, the center of the antenna coils (first layer antenna coil 21, second layer antenna coil 22,..., N layer antenna coil 2n) of each layer arranged in a plurality of layers is on the same central axis. The antenna coils of each layer arranged in a divided manner are wound in the same direction along the outer periphery of each layer with the same central axis as the center. In addition, in order to connect the antenna coils of each layer arranged in series through the through-hole 10, the end of winding of the antenna coil of the younger side and the start of winding of the container coil of the older side The through holes 10 are sequentially connected.

  Here, FIG. 2 is a schematic diagram showing an example of the structure of the antenna coil of the read / write device according to the present invention, and the antenna coil 2 is divided into n layers (n ≧ 2) of the flexible substrate 1 and arranged. An example of winding in the same direction and in the same direction (counterclockwise in FIG. 2) so that the central axes coincide with each other along the outer circumference of each layer. Show.

  As shown in FIG. 2, the winding end 91 of the first layer antenna coil 21 of the first layer 11 is connected to the winding start 82 of the second layer antenna coil 22 of the next second layer 12, and the second layer 12 second The winding end 92 and the winding start of the antenna coil of each layer are sequentially connected using the through hole 10 such that the winding end 92 of the layer antenna coil 22 is connected to the winding start of the antenna coil of the next layer. Thus, even if the number of turns of the entire antenna coil is increased, the antenna coil is divided and arranged in each layer, so that the diameter of each antenna coil is not reduced, and a decrease in magnetic field strength is prevented. it can.

  It should be noted that the first layer 11 of the first layer 11 that is the first layer 11 and the winding start 8n of the nth layer antenna coil 2n of the nth layer 1n that is the last layer (the previous layer ( The winding end 9n of the nth layer antenna coil 2n to which the winding end of the (n-1) th layer) antenna coil is connected is the first layer 11 of the layer that becomes the front (front) surface of the flexible substrate 1 Connected to the antenna connection terminal of the control circuit 3 mounted on

  Further, as shown in FIG. 1A, the control circuit 3 mounted on the first layer 11 is near the center of the flexible substrate 1, that is, the position that coincides with the central axis 6 of the antenna coil 2 that is dividedly arranged in each layer. (Preferably, the center position of the control circuit 3 is disposed so as to coincide with the center axis of the antenna coil 2), and the antenna coil is generated by the current flowing through the control circuit 3. Consideration is made so that the influence on the magnetic field generated by 2 is minimized.

  Each component such as a circuit element constituting the control circuit 3 is arranged only on one surface, that is, the front surface of the flexible substrate 1, and the other surface, that is, the back surface of the flexible substrate 1, is completely free of components such as circuit elements. The mounting surface is a smooth surface that is not mounted, and an attachment means that can attach the read / write device, that is, the flexible substrate 1 to the inner wall surface of another device (that is, a host device) on which the read / write device is mounted is formed on the back surface. Has been. Specifically, as shown in FIG. 1B, as the attachment means, for example, a double-sided tape 7 is pasted on the back surface of the flexible substrate 1, and the read / write device is built in another device (that is, a host device). Sometimes, the cover of the double-sided tape 7 is peeled off and attached to the inner wall surface of the other device, so that it can be fixedly attached.

  Next, a configuration example of a connection cable, which is a connection unit that electrically connects the read / write device configured as shown in FIG. 1 and the host device, will be described with reference to FIG. FIG. 3 is a schematic diagram showing one configuration example of the connection cable of the read / write device according to the present invention. As shown in FIG. 3, the connection cable 4 of the read / write device is formed by performing wiring on any one layer of the multi-layer flexible substrate 1.

  In the case of the example shown in FIG. 3, for example, a layer for forming connection means for electrically connecting the i-th layer 1 i (1 <i <n) of the layer where the antenna coil 2 is not arranged with the host device. As the connection cable 4 having a host device connection terminal 5 connected to the host device at one end, the plastic i-th layer 1i is extended to a predetermined appropriate length, and the connection cable 4 Is extended to the center on the i-th layer 1i, and the connection cable 4 is connected to the connection terminal of the control circuit 3 disposed on the first layer 11 on the surface of the flexible substrate 1 by the through hole 10. .

  As described above, by using any one of the multi-layered flexible boards 1 (i-th layer 1i in the case of FIG. 3), by forming the connection cable 4 for electrical connection with the host device, Integration of the mounting portions of the antenna coil 2, the control circuit 3, and the connection cable 4 can be realized.

  Next, an example of a print pattern showing the electrical wiring system of the control circuit 3 mounted on the hierarchy, for example, the first layer 11 on the surface of the flexible substrate 1 will be described with reference to FIG. FIG. 4 is a schematic diagram showing an example of a print pattern showing a wiring system on the flexible substrate 1 of the control circuit 3 of the read / write device according to the present invention. As shown in FIG. 4, in order to perform electrical connection as the control circuit 3, as a printed pattern using copper foil, a land for mounting each circuit component, wiring between each circuit component, jumper wire, power supply Lines, connection cables, ground planes, and the like are arranged in each layer of the flexible substrate 1.

  In the example of FIG. 4, on the first layer 11 on which the control circuit 3 is mounted, a component mounting surface / inter-component wiring surface 51 is formed as a printed pattern for wiring between circuit component mounting lands and circuit components. On the i-th layer 1i forming the connection cable 4 for connection with the host device, the connection cable installation surface / part as a print pattern for connecting cable 4, the lead-out line to the connection cable 4 and jumper wiring between circuit parts In the example, the intermediate wiring surface 5 i is formed, and the last n-th layer 1 n is formed with the ground surface 5 n for applying the electrical ground potential of the control circuit 3. In the present embodiment, the ground plane 5n is formed in the final nth layer. However, if an electrical ground plane for the control circuit 3 can be formed, it is formed in a layer other than the nth layer. You may make it do.

  4, the ground pattern of the ground surface 5n formed in the last n-th layer 1n is generally centered on a position coincident with the central axis of the antenna coil 2. It is desirable to have a wide copper foil surface that covers the entire arrangement range where the one-layer control circuit 3 is arranged. However, when the ground plane 5n is formed as a continuous plane covering a wide area, the magnetic field generated by the antenna coil 2 intersects with the ground plane 5n, and a large eddy current flows, and as a result, the antenna There is an adverse effect that the magnetic field intensity generated by the coil 2 is weakened.

In order to suppress the generation of such eddy (eddy) currents in write, as shown in FIG. 5, toward the outer periphery from the center 6n _c of the center axis or the ground surface 5n of the antenna coil 2, a plurality of radially slits 7n Is forming. Figure 5 is a schematic diagram showing an example of a ground pattern 6n forming a ground plane 5n of the reading and writing apparatus according to the present invention, radially toward the outer periphery from the center 6n _c of the center axis or the ground surface 5n of the antenna coil 2 An example in which 16 cuts 7n are formed is shown.

Note that the notch 7n of the ground surface 5n is closer to the peripheral side (outer peripheral side) of the flexible substrate 1 close to the antenna coil 2, that is, the magnetic field strength of the antenna coil 2 is higher, and the current density of the eddy current is higher. As shown in FIG. 5, the higher the portion, the larger the number of cuts 7n, and / or the wider the cut 7n, the closer to the peripheral side (outer peripheral side) of the flexible substrate 1, and / or it is desirable to either cut 7n does not reach even to the center 6n _c of the ground plane 5n shape.

  By using a ground pattern 6n in which a notch 7n is formed in the ground surface 5n, the ground surface 5n is prevented from becoming a continuous copper foil surface over a wide range, and thus an eddy current is generated. The effect which suppresses can be acquired.

  Next, an example of the circuit configuration of the control circuit 3 of FIG. 1 showing an example of the configuration of the read / write device according to the present invention will be described with reference to FIG. 6 is a circuit diagram showing an example of the circuit configuration of the control circuit 3 of the read / write device according to the present invention. FIG. 6A shows an example of the overall circuit configuration of the control circuit 3, and FIG. These show an example of the circuit configuration of the antenna circuit 40 connected to the modulation / demodulation circuit 31 of the control circuit 3.

  As shown in the circuit diagram of FIG. 6A, the control circuit 3 mainly converts a voltage to be read / written to / from a portable recording medium into a modulation / demodulation circuit 31 for modulating / demodulating data and a voltage value to be supplied to the oscillation circuit 33. The conversion circuit 32, the oscillation circuit 33 that oscillates at a predetermined frequency, the antenna circuit 40 that connects the antenna coil 2, and the host device connection terminal 5 for connection to the host device 50 are configured. Here, the digital signal processing related to the data read / written by the read / write device is configured to be performed on the host device 50 side.

  As shown in “power supply” in FIG. 6, the modem circuit 31 performs modulation / demodulation of read / write data that is fed from the host device 50 via the host device connection terminal 5 and exchanged with the portable recording medium. Further, communication relating to read / write data between the modem circuit 31 and the host device 50 via the host device connection terminal 5 is performed using the “digital signal input” and “digital signal output” signal lines shown in FIG. . Further, the modem circuit 31 is provided with a terminal for synchronizing with the host device 50. As shown in "Synchronization with host device" in FIG. 6, the host device 50 is connected via the host device connection terminal 5. And a clock output terminal (not shown).

  The voltage conversion circuit 32 is a circuit that converts a power supply voltage fed from the host device 50 via the host device connection terminal 5 into an operating voltage to be fed to the oscillator of the oscillation circuit 33. For example, a converter diode Consists of. The voltage conversion circuit 32 may be housed in the oscillation circuit 33 and configured as a part of the oscillation circuit 33.

  The oscillation circuit 33 has a carrier frequency (in this embodiment, a 13.56 MHz frequency for a non-contact IC card defined in the ISO standard as one of portable recording media read / written by the read / write device). This is for generating an unmodulated carrier. The oscillator circuit 33 may be any oscillator as long as it can generate a 13.56 MHz unmodulated carrier, and not only a crystal oscillator widely used at present, but also a MEMS (Micro Electro- The same effect can be obtained even with an oscillator (Mechanical Systems). Here, the frequency of 13.56 MHz is a carrier frequency of a signal transmitted / received to / from a portable recording medium.

  Next, the configuration of the antenna circuit 40 when the antenna coil 2 includes the first antenna element L1 and the second antenna element L2 will be described with reference to the circuit diagram shown in FIG.

  The antenna coil 2 connected to the antenna circuit 40 is preferably composed of a first antenna element L1 and a second antenna element L2 having the same inductance, and the antenna circuit 40 is mainly configured as shown in FIG. Desirably, the first capacitor C1 and the second capacitor C2 having the same capacitance, and the third capacitor C3 and the fourth capacitor C4 having the same capacitance, one end of the first antenna element L1, and the second antenna element. A resistor R1 connected between one end of L2 is provided.

Further, the antenna circuit 40 has a ground (GND) terminal for grounding the other end of the first antenna element L1 and the second antenna element L2 on the antenna coil 2 side, and one end of the first antenna element L1 is connected to the first capacitor C1. via the second antenna connecting terminal 31 of the first first connection terminal 41 for connection to the antenna connection terminal 31 _1, the modem circuit 31 to one end of the second antenna element L2 via the second capacitor C2 of the modem circuit 31 ₂ the second connection terminal 42 for connection to, for connecting the receiving end ₃₁₃ of the modulation and demodulation circuit 31 to a connection point between the first capacitor C1, one end of the first antenna element L1 is connected to the third capacitor C3 The third connection terminal 43 is included. The third connection terminal 43 receives a reception signal related to read data from a portable recording medium such as a non-contact IC card.

  Note that one end of each of the third capacitor C3 and the fourth capacitor C4 is connected to one end of each of the first antenna element L1 and the second antenna element L2, and the other end is a ground (GND) terminal for grounding. Connected to.

  Next, a portable recording medium such as an ELWISE (registered trademark) card conforming to the ISO standard (for example, requiring a minimum operating magnetic field of about 3.5 A / m) such as a non-contact IC card (that is, at least It is possible to read / write the recorded content of a non-contact IC card having a high operating magnetic field, and to reduce the opening area of the antenna coil 2 (for example, 35 mm × 25 mm or less), thereby reducing the size of the read / write device. 6 to enable the circuit parameter values of the antenna coil 2 and the antenna circuit 40 (that is, the inductance of each of the first antenna element L1 and the second antenna element L2, and the electrostatic capacitance of each of the first to fourth capacitors C1 to C4). (Capacity) will be described.

  Generally, in order to reduce the size of an antenna, it is necessary to make the opening area of the antenna coil 2 as small as possible. However, if the opening area of the antenna coil 2 of the read / write device is made too small, a sufficient magnetic field cannot be secured, and the recorded content of the non-contact IC card can be read / written even if the non-contact IC card is brought close to the read / write device. The problem of being unable to do so occurs.

  Here, in the present embodiment, assuming that the antenna coil 2 can be sufficiently accommodated in the portable device, the inductance assumed for each of the first antenna element L1 and the second antenna element L2 forming the antenna coil 2 is as described above. Thus, they are equal to each other and both are 1.0 μH.

  Further, in the present embodiment, as described above, while making it possible to read and write the recording contents relating to a portable recording medium such as an ELWISE (registered trademark) card that requires a large amount of power, such as a non-contact IC card, In order to reduce the size of the read / write device, circuit parameter values (capacitances of the first to fourth capacitors C1 to C4) of the antenna circuit 40 in FIG. 6B are calculated using the following experimental procedure. ing.

  In order to make the opening area of the antenna coil 2 the smallest and to enable the most efficient power transmission to the portable recording medium, between the modem circuit 31 and the antenna circuit 40 in FIG. It is necessary to take impedance matching. Here, the state where the impedance matching between the two is taken is a state where “impedance seen from the output side of the modem circuit 31” and “impedance on the antenna circuit 40 side” are complex conjugates. That is, in the state where the impedance matching between the two is taken, if the “impedance seen from the output side of the modulation / demodulation circuit 31” is found, the “impedance on the antenna circuit 40 side” that is the complex conjugate thereof can be obtained.

  Accordingly, if the capacitances of the first to fourth capacitors C1 to C4 of the antenna circuit 40 are set so as to match the “impedance on the antenna circuit 40 side”, the first antenna element L1 and the second antenna element L2 are set. The antenna coil 2 having a predetermined opening area that can be sufficiently mounted on an ultra-small portable device has the highest magnetic field strength and the most efficient power transmission.

  A specific experimental procedure for calculating the capacitances of the first to fourth capacitors C1 to C4 forming the matching circuit of the antenna circuit 40 is as follows.

  (1) After mounting components other than the matching circuit of the antenna circuit 40 (components of the control circuit 3 other than the matching circuit of the antenna circuit 40 in FIG. 6, the antenna coil 2 and the connection cable 4) on the flexible substrate 1, FIG. A trimmer capacitor capable of manual adjustment with a maximum capacity of about 100 pF is mounted at each position of the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 of the antenna circuit 40.

  (2) After that, a 13.56 MHz carrier (carrier frequency) compliant with the ISO standard is actually emitted from the antenna coil 2, and the first capacitor C1, the second capacitor C2, While manually adjusting the four trimmer capacitors mounted at the positions of the third capacitor C3 and the fourth capacitor C4, the amplitude of the magnetic field strength is observed with an oscilloscope.

  Here, in order to equalize the setting of the two matching circuits of the antenna coil 2 (that is, the first antenna element L1 and the second antenna element L2 in FIG. 6 set to inductances of 1.0 μH which are equal to each other). As described above, the capacitance of the “first capacitor C1 and the second capacitor C2” and the capacitance of the “third capacitor C3 and the fourth capacitor C4” are set to the same value as much as possible. Manually adjust the trimmer capacitors so that their rotation angles are as uniform as possible.

  (3) As a result of observing the amplitude of the magnetic field intensity with an oscilloscope while manually adjusting the capacitance value of each trimmer capacitor, the first capacitor C1, the second capacitor C2, the second capacitor C2, Manual adjustment of the capacitance values of the trimmer capacitors of the third capacitor C3 and the fourth capacitor C4 is stopped.

  (4) Remove the trimmer capacitor mounted at each position of the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 from the flexible substrate 1 in the state of (3), and install the microcapacitor. Used to measure the capacitance of each trimmer capacitor. The measurement results of the capacitance values of the trimmer capacitors mounted on the first to fourth capacitors C1 to C4 in this experiment were C1 = 25 pF, C2 = 16 pF, C3 = 80 pF, and C4 = 60 pF.

  (5) Therefore, from the measurement result of the above (4), as the most desirable value of the first capacitor C1 and the second capacitor C2, the capacitance value in the range of 16 to 25 pF or the average value of both is 20.5 pF. It is desirable to set the capacitance value 22 pF of the commercially available capacitor closest to the capacitor, and the most desirable value of the third capacitor C3 and the fourth capacitor C4 is a capacitance value in the range of 60 to 80 pF, or an average value of both It can be determined that it is desirable to set the capacitance value 68 pF of the commercially available capacitor closest to 70 pF.

  In other words, the first capacitor C1 and the second capacitor C2 that desirably have the same capacitance are desirably a fixed capacitor having a capacitance of 22 pF or a variable capacitor having a capacitance within a variable range of 22 pF. Preferably, the third capacitor C3 and the fourth capacitor C4 having the same capacitance are mutually fixed capacitors having a capacitance of 68 pF or variable capacitors including a capacitance of 68 pF in the variable range. It can be said that it is desirable.

  Based on the experimental results, the antenna coil 2, the control circuit 3, and the connection cable 4 to the host device are integrally mounted on a single flexible substrate, and the magnetic field inside the antenna coil 2 is mounted. A structure in which the control circuit 3 is arranged so as to be concentrated in the vicinity of the position corresponding to the central axis where the intensity is the weakest is adopted, and the ground plane 6n of the ground plane 5n to which the ground potential of the control circuit 3 is applied is provided as a ground plane. An antenna circuit that employs a structure in which a plurality of cuts 7n are formed radially from the center of 5n toward the outer periphery and has the capacitance values of the first to fourth capacitors C1 to C4 as described above as circuit parameter values 40 and the antenna coil 2 having the inductances of the first and second antenna elements L1 and L2 as described above. Therefore, not only can the opening area of the antenna coil 2 be reduced and the size can be reduced, but also the most efficient power transmission can be performed, and reading and writing of recorded contents of a non-contact IC card with high power consumption It is also possible to provide a read / write device (reader / writer) that can also be used.

(Effect of this embodiment)
As described above, the antenna coil 2, the control circuit 3, and the connection cable 4, which are constituent elements of the read / write device, are integrated by being mounted on one flexible substrate 1, and can be miniaturized and have a plastic structure. Thus, even in an extremely narrow housing such as an ultra-small portable device that fits in the palm, the read / write device can be incorporated in accordance with the shape inside the housing.

  Further, the control circuit 3 is intensively disposed in the vicinity of the position corresponding to the central axis inside the antenna coil 2 where the magnetic field intensity is the weakest, and from the center of the ground surface 5n corresponding to the central axis of the antenna coil 2. By providing the ground pattern 6n formed with radial cuts 7n toward the outer peripheral side, a large magnetic field strength can be obtained as the antenna coil 2, and even a portable recording medium that requires a large amount of power for reading and writing recorded contents. It can be operated reliably, and the recorded contents can be read and written accurately.

  Furthermore, by incorporating a read / write device (reader / writer) like this, it is possible to realize a portable device that can be miniaturized and has various functions.

It is a schematic diagram which shows one structural example of the reading / writing apparatus by this invention. It is a schematic diagram which shows an example of the structure of the antenna coil of the reading / writing apparatus by this invention. It is a schematic diagram which shows one structural example of the connection cable of the reading / writing apparatus by this invention. It is a schematic diagram which shows an example of the print pattern which shows the wiring system etc. on the flexible substrate of the control circuit of the reading / writing apparatus by this invention. It is a schematic diagram which shows an example of the ground pattern which forms the ground surface of the reading / writing apparatus by this invention. It is a circuit diagram which shows an example of the circuit structure of the control circuit of the reading / writing apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flexible substrate, 2 ... Antenna coil, 3 ... Control circuit, 4 ... Connection cable, 5 ... High-order apparatus connection terminal, 6 ... Center axis of antenna coil, 7 ... Double-sided tape, 10 ... Through hole, 11 ... 1st Layer 12 ... 2nd layer, 1i ... i layer, 1n ... n layer, 21 ... 1st layer antenna coil, 22 ... 2nd layer antenna coil, 2n ... nth layer antenna coil, 31 ... modulation / demodulation circuit, 31 DESCRIPTION OF SYMBOLS ₁ ... 1st antenna connection end, 31 ₂ ... 2nd antenna connection end, 31 ₃ ... Reception end, 32 ... Voltage conversion circuit, 33 ... Oscillation circuit, 40 ... Antenna circuit, 41 ... 1st connection terminal, 42 ... 2nd Connection terminal 43 ... Third connection terminal 50 ... Host device 51 ... Component mounting surface / inter-component wiring surface 5i ... Connection cable installation surface / inter-component wiring surface (jumper) 5n ... Ground surface 6n ... Ground pattern , 6n c _... Gras Center of Dopatan, 7n ... cut (radial), 81,82, ..., 8n ... winding start, 91,92, ..., 9n ... winding end.

Claims (15)

In a read / write device for reading / writing recorded contents of a portable recording medium, an antenna coil that is electromagnetically coupled to the portable recording medium on a flexible substrate having a plurality of levels of plasticity, and the portable via the antenna coil A control circuit that reads / writes data from / to a recording medium, and a connection means that electrically connects to a host device that controls the operation of the control circuit are mounted , and a ground that provides a ground potential of the control circuit The surface is formed on any level of the flexible substrate so as to cover the arrangement area of the control circuit with the position coinciding with the central axis of the antenna coil as a center, and from the center of the ground plane A read / write device , wherein a plurality of slits are formed radially toward the outer peripheral side . 2. The read / write device according to claim 1, wherein the control circuit is an oscillation circuit that oscillates at a predetermined frequency, an antenna circuit that is connected to the antenna coil and performs at least impedance matching, and read / write between the portable recording medium. A read / write device comprising at least a modulation / demodulation circuit for modulating / demodulating data to be transmitted. In reading and writing apparatus of claim 1 or 2, before Symbol antenna coil, it is arranged by dividing into at least two levels or more of a plurality of hierarchies of the flexible substrate comprising a plurality of layers, and is divided into a plurality of layers A read / write device characterized in that the antenna coils arranged in a connected manner are connected by through holes.   4. The read / write device according to claim 3, wherein when the antenna coils arranged in a plurality of layers are connected to each other, the winding end of the antenna coil of the younger number side and the antenna coil of the old number side layer are connected. Read / write device characterized by sequentially connecting the beginning of winding.   5. The read / write device according to claim 3, wherein each of the antenna coils arranged in a plurality of layers is arranged in the same direction along the outer periphery of each layer with the same central axis as the center. A reading / writing device characterized by being wound toward the head.   6. The read / write device according to claim 5, wherein the control circuit mounted on the flexible substrate is concentrated in the vicinity of a position coinciding with the central axis of the antenna coil. 7. The read / write device according to claim 1 , wherein a shape in which the number of cuts increases as the distance from the outer peripheral side of the layer on which the ground surface is formed, and / or a layer on which the ground surface is formed. The read / write device has a shape in which the width of the cut becomes wider as it is closer to the outer peripheral side of the wire and / or a shape in which any of the cuts does not reach the center of the ground surface. In reading and writing apparatus according to any one of claims 1 to 7, wherein the connecting means for connecting to the host system and electrical are formed on one of the hierarchy on the flexible substrate, and defining the hierarchical pre Forming a connection cable having one end of a host device connection terminal for connecting to the host device, extending the length, and extending the connection cable to the center of the hierarchy A read / write device characterized in that a connection terminal is connected by a through hole. Power in the reading and writing apparatus according to any one of claims 2 to 8, the oscillating circuit is equipped with one of the oscillator of the crystal oscillator or MEMS (Micro-electro-mechanical device) oscillator, and fed from the host system A read / write device comprising a voltage conversion circuit for converting a voltage into an operating voltage of the oscillator. In reading and writing apparatus according to any one of claims 2 to 9, wherein the antenna coil, the antenna circuit comprises a first antenna element and second antenna element, connecting the antenna coil, one end of said first antenna element Is connected to the first antenna connection end of the modulation / demodulation circuit via the first capacitor, is connected to the ground via the third capacitor, and one end of the second antenna element is connected to the second capacitor. To the second antenna connection end of the modulation / demodulation circuit, to the ground via a fourth capacitor, and to connect the other end of the first antenna element and the other end of the second antenna element to the ground. And receiving a reception signal from the portable recording medium at a connection point between the first capacitor and the third capacitor. Write apparatus characterized by being constructed by connecting the receiving end of the demodulation circuit. The read / write device according to claim 10 , wherein inductances of the first antenna element and the second antenna element are equal to each other, and capacitances of the first capacitor and the second capacitor are equal to each other, and The read / write device, wherein the third capacitor and the fourth capacitor have the same capacitance. 12. The read / write device according to claim 11 , wherein a carrier frequency of a signal transmitted / received to / from the portable recording medium is 13.56 MHz, and the first antenna element and the second antenna element are 1.0 μH. And the first capacitor and the second capacitor are a fixed capacitor having a capacitance of 22 pF or a variable capacitor including a capacitance of 22 pF within a variable range, and the third capacitor and The read / write device according to claim 4, wherein the fourth capacitor is a fixed capacitor having a capacitance of 68 pF or a variable capacitor including a capacitance of 68 pF in a variable range. In reading and writing apparatus according to any one of claims 1 to 12, each part constituting the control circuit, the disposed only on one side of the flexible substrate, the reading and writing apparatus to the inside wall of the host system A read / write device, characterized in that an attaching means that can be attached is formed on the other surface of the flexible substrate. 14. A portable portable device having a read / write device for reading / writing recorded contents of a portable recording medium and performing various types of information processing and information communication, wherein the read / write device comprises the read / write device according to any one of claims 1 to 13. A portable device characterized by being made. The portable device according to claim 14 , wherein the portable device includes at least one of a mobile phone, a PHS terminal, a PDA (personal digital assistant), a portable music player, and a portable notebook PC.

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