JP5724393B2 - Communication module, reader / writer - Google Patents

Description

  The present invention relates to a communication module including a circuit for matching with an antenna and a reader / writer using the communication module.

  For example, in near field communication (NFC), from the application of the device to which it is applied, the components (antennas and modules) for near field communication processing built into the device are reduced in size and space. Is often required. In response to such demands, some circuit components can be built into the board using a component built-in wiring board as a module, and the size can be reduced. On the other hand, an antenna generally requires a larger space than a module, but the available space is not constant depending on the applied device, and is often designed according to the actual device.

  The module that drives the antenna needs a matching circuit (matching circuit) that performs matching with the characteristics of the antenna. When the matching circuit is composed of circuit components with a built-in wiring board, it is convenient for miniaturization as a module. On the other hand, a matching circuit according to the characteristics of various antennas can be used. It becomes impossible at the stage.

JP 2004-23584 A JP 2003-188340 A

  The present invention has been made in consideration of the above-described circumstances, and is a communication module having a wiring board in which components can be incorporated, and a communication module capable of adjusting matching according to antenna characteristics and a reader using the same The purpose is to provide a writer.

In order to solve the above problems, a communication module according to one embodiment of the present invention includes a wiring board, a communication processing IC provided in the wiring board, and the wiring electrically connected to the communication processing IC. A matching circuit provided on a plate for matching with an antenna provided outside, wherein the matching circuit is a capacitance element connected in series from the communication processing IC. A second capacitance element which is a capacitance element connected between a node passing through the first capacitance element and the ground, and an element to which one end is connected to the node and an antenna is connected to the other end a circuit of a passive device circuitry and a resistor element is configured at the first capacitance Jer Is a circuit element made by parallel connection of a surface mount type first capacitor built in the wiring board and a surface mount type second capacitor mounted on the surface of the wiring board, The second capacitance element was formed by parallel connection of a surface mount type third capacitor built in the wiring board and a surface mount type fourth capacitor mounted on the surface of the wiring board. A circuit element, wherein the resistance element is a series connection of a first surface mount type resistor built in the wiring board and a second surface mount type resistor mounted on the surface of the wiring board. characterized in that there.

That is, in this communication module, the matching circuit for the antenna is as follows. First, the matching circuit includes a first capacitance element that is a capacitance element connected in series from the communication processing IC, and a capacitance element that is connected between a node that has passed through the first capacitance element and the ground. A circuit of a passive element network comprising a second capacitance element and a resistance element, one end of which is connected to the node and the other end of which is connected to an antenna ; and The first capacitance element is a circuit element formed by parallel connection of a surface mount type first capacitor built in the wiring board and a surface mount type second capacitor mounted on the surface of the wiring board. And the second capacitance element is a surface mount type third capacitor built in the wiring board. Circuit element formed in parallel connection with a surface mount type fourth capacitor mounted on the surface of the wiring board, and the resistance element is a surface mount type first resistor built in the wiring board. And a surface mount type second resistor mounted on the surface of the wiring board . Therefore, it is possible to adjust the element constant set only with the built-in passive element component by the passive element component mounted on the surface. Therefore, the communication module can be adjusted for matching according to the characteristics of the antenna.

Further, a reader / writer according to another aspect of the present invention is provided in the wiring board, the communication processing IC provided in the wiring board, and the wiring board electrically connected to the communication processing IC. A matching circuit for matching with an antenna provided outside, wherein the matching circuit is a capacitance element connected in series from the communication processing IC, and the first capacitance element A second capacitance element that is a capacitance element connected between a node that has passed through the capacitance element and ground; a resistance element that is an element to which one end is connected to the node and an antenna is to be connected; a circuit of a passive device circuitry is configured to have a first capacitance element, the wiring board A circuit element formed by parallel connection of a built-in surface mount type first capacitor and a surface mount type second capacitor mounted on the surface of the wiring board, wherein the second capacitance element is A circuit element formed by parallel connection of a surface mount type third capacitor built in the wiring board and a surface mount type fourth capacitor mounted on the surface of the wiring board; A reader / writer circuit module in which the element is a series connection of a first resistor mounted on the surface of the wiring board and a second resistor mounted on the surface of the wiring board ; And an antenna connected to the matching circuit of the reader / writer circuit module.

  This reader / writer is configured to be a reader / writer by providing the communication processing IC included in the communication module as a communication processing IC for reading and writing data, and further providing an antenna. Therefore, a reader / writer using a reader / writer circuit module capable of adjusting the matching according to the characteristics of the antenna is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, it is a communication module which has a wiring board which can incorporate components, Comprising: The communication module which can adjust a matching according to the characteristic of an antenna, and a reader / writer using the same can be provided.

The block diagram which shows the communication module which is one Embodiment of this invention. FIG. 2 is a schematic cross-sectional view showing the communication module shown in FIG. 1 including the structure of a wiring board. FIG. 3 is a component layout diagram of external mounting / internal mounting of a wiring board included in the communication module shown in FIG. 1. The table | surface which shows the design example of the matching circuit at the time of applying the communication module shown in FIG. 1 to each antenna from which a characteristic differs.

As state like the present invention, the passive element circuit network of the matching circuit, passes through the first and the capacitance element the capacitance elements connected in series from the communication processing IC, and the capacitance element of the first node And a second capacitance element that is a capacitance element connected between the ground and the ground, and a resistance element that is connected to the node at one end and to which an antenna is to be connected at the other end. Tei Ru.

This ensures that the capacitor for obtaining a capacitance, and resistance is small as parts, are particularly well suited to miniaturization as a communication module.

Further, as the state-like, the first capacitance element, a first capacitor surface mount type which is built in the wiring board, has been surface mount second mounting on a surface of the wiring board a circuit element made of parallel connection of the capacitor, the second capacitance element, a third capacitor surface mount type which is built in the wiring board, which is mounted on a surface of the wiring board table Ru der circuit elements made of parallel connection of the fourth capacitor of a surface mounting type.

This ensures that the adjustment of the capacitance value of the capacitance elementary theft is, the added value of the capacitance value is likely to do Ri Do the combined capacitance value.

Further, as the state-like, wherein the resistance element is a first resistor in surface mount incorporated in the wiring board, the second resistor of surface mount mounted on the surface of the wiring board Ru series connection der.

This ensures that the adjustment of the resistance value of the resistor elementary theft is, the sum of the resistance value is easy to do Ri Do the combined resistance value.

  As an embodiment, the communication processing IC may generate a transmission signal in a 13.56 MHz frequency band toward the antenna via the matching circuit. The 13.56 MHz frequency band is one standard frequency band used in NFC. The concept is the same for other standards with different frequency bands.

  Based on the above, embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram illustrating a communication module according to an embodiment of the present invention. The communication module 10 is a module (= reader / writer circuit module) having a function of reading or writing data in a contactless manner with a medium (data carrier) carrying information as a specific function.

  As shown in FIG. 1, the communication module 10 includes a communication processing IC, a crystal component 12, a power supply component 13, other components 14, an EMC (electro-magnetic compatibility) filter 15, and a matching circuit 16. These components are mounted on a component built-in wiring board (FIG. 2) described later. An antenna 17 is connected to the reader / writer circuit module 10, and the form of the antenna 17 (an example will be described later; FIG. 4) is designed according to the available space of the applied device. .

  The communication processing IC 11 is an IC that performs data read / write processing. Data, control information, and the like are exchanged as necessary with a host included in a device to which the module 10 is applied. Data obtained from the host is modulated so as to be compatible with short-range wireless communication, and output as a transmission signal to the EMC filter 15 and the matching circuit 16 side. Conversely, the RF signal input from the data carrier (not shown) via the antenna 17 and the matching circuit 16 is received and subjected to processing such as demodulation, and the data obtained by the processing is sent to the host side as necessary. To pass.

  The crystal component 12 is a peripheral component that is provided in electrical connection with the communication processing IC 11 and is necessary for clock generation of the communication processing IC 11. The power supply component 13 is a peripheral component necessary for stable power feeding to the communication processing IC, which is provided by being electrically connected to the communication processing IC. The other component 14 is a peripheral component for other functions that is provided by being electrically connected to the communication processing IC 1. This function includes, for example, guiding the received RF signal to the communication processing IC 11 without using the function of the EMC filter 15 in the case of data reading.

  The EMC filter 15 is a low-pass filter having a function of cutting a frequency band higher than the frequency band used for communication. That is, the output signal from the communication processing IC 11 is filtered with a specific characteristic and is output to the matching circuit 16. This module 10 can use a frequency band having a center frequency of 13.56 MHz, for example, for communication. Therefore, the EMC filter 15 has a cut-off frequency in consideration of a frequency band that spreads around this frequency band. Is set. As shown in the figure, the EMC filter 15 used here is a secondary low-pass filter composed of L and C, and its output side is connected to both ends of the antenna 17, so that the circuit configuration with the ground as the center of symmetry is provided. It has become.

  The matching circuit 16 is a circuit for matching power with the antenna 17. If the matching is insufficient, sufficient power cannot be supplied to the antenna 17 (or the power received by the antenna 17 from the outside cannot be efficiently taken in), and the communication performance of the module 10 is deteriorated. In general, when an antenna is used, power matching with the antenna is essential in wireless communication.

  The matching circuit 16 here has capacitors C3 and C4 (C5 and C6) connected in series from the communication processing IC 11 via the EMC filter 15, as shown in the figure. In addition, capacitors C7 and C8 (C9 and C10) are connected between the node that has passed through the capacitors C3 and C4 and the ground. Further, one end is connected to the node, and the other end has a resistor R1 (R2) to which the antenna 17 is connected. Since the output side of the matching circuit 16 is connected to both ends of the antenna 17, the circuit is configured with the ground as the center of symmetry, which is the same as the EMC filter 15.

  When viewed as a circuit element, the matching circuit 16 includes three elements, that is, a series-connected capacitance element, a ground-connected capacitance element, and a series-connected resistance element. However, each of these circuit elements is configured so as to obtain a desired value by combining two components. More specifically, the capacitance element is configured by connecting two components in parallel as shown in the figure. The resistance element can possibly be configured by connecting two parts in series (drawn with a broken line), but here it is configured as a single part.

  One of the two parts functioning as each circuit element is built in the wiring board constituting the module 10, and the other is mounted on the outer surface of the wiring board. By arranging in this way, it is possible to adjust the matching according to the characteristics of the antenna 17 by changing the component constant of the mounting on the outer surface. In FIG. 1, C3 and C7 (C5 and C9) are capacitors built in the wiring board, and C4 and C8 (C6 and C10) are capacitors mounted on the outer surface of the wiring board. The capacitor C1 (C2), which is a component constituting the EMC filter 15, is also provided here as a built-in component. The other components of the EMC filter 15 and the matching circuit 16 are mounted on the outer surface of the wiring board.

  According to the reader / writer circuit module 10, the size can be reduced by using the component built-in wiring board, and the matching can be adjusted according to the characteristics of each antenna 17 only by changing the constants of the components mounted on the outer surface. Is possible. That is, a component built-in wiring board that is versatile with respect to changes in the characteristics of the antenna 17 can be used.

  As a configuration of the matching circuit 16, in addition to the above-described specific passive element network by RC, another configuration generally known as a matching circuit can be used. For example, a passive element network ((1) C, (2) CR, (3) CL, (4) CLR) including at least a capacitor, or a passive element network ((5) L, (6) LR) including at least an inductor. (7) LC, (8) LCR). Even in such a case, for each circuit element, if a built-in component and a secondary component for constant adjustment are provided in parallel or in series with each other, and the component for constant adjustment is externally mounted, desired adjustment can be achieved. It is possible on the wiring board.

  Whether to connect in parallel or in series is as follows. In the case of a capacitor as a circuit element, the parallel connection is easier to design. This is because in the case of parallel connection, the added value of the capacitance value becomes the combined capacitance value. On the other hand, when an inductor or a resistor is used as the circuit element, the series connection is easier to design. This is because in the case of series connection, the added value of the inductance value or resistance value becomes the combined inductance value or combined resistance value. However, even if the connection that is not easy to design is used, the effect that the matching can be adjusted according to the characteristics of each antenna 17 remains the same.

  FIG. 2 is a schematic cross-sectional view showing the communication module 10 shown in FIG. 1 including the structure of the wiring board. The communication module 10 shown in FIG. 1 can be configured using, for example, a wiring board having a structure as shown in FIG. The communication module 10 includes a surface-mounted passive element component 41 as a built-in component and a surface-mounted passive element component 71 as a surface-mounted component. The component 41 corresponds to C3, C7 (C5, C9) and C1 (C2), and the component 71 corresponds to C4, C8 (C6, C10), R1 (R2), and L1 (L2).

  In addition to the surface-mount type passive element components 41 and 71, the communication module 10 includes a wiring pattern 21 on the back surface including terminal electrodes for external connection, a wiring pattern 26 on the front surface, an inner wiring layer (inner layer wiring pattern) 22, 23, 24, 25, insulating layer 1, 2, 3, 4, 5, interlayer connection conductor 31, 32, 34, 35, through-hole conductor 33, solder resist 61, 62 , Solder 51 and 81. The wiring board used by the communication module 10 is a six-layer board having six wiring layers separated by insulating layers 1 to 5.

  Each of the insulating layers 1 to 5 is a rigid layer made of, for example, a glass epoxy resin. The wiring patterns 21 and 26 on the front and back surfaces and the wiring layers 22 to 25 on the inner layer are layers obtained by, for example, performing a desired patterning process on a copper foil by a known photolithography technique. The interlayer connection conductors 31, 32, 34, and 35 are connected bodies of conductive compositions that are interposed between the wiring patterns through the insulating layers 1, 2, 4, and 5, respectively. It functions as an electrical connection path.

  Furthermore, the solder resists 61 and 62 are protective films formed on the entire surface of the insulating layer 1 or the insulating layer 5 except for the region where the solder is to be placed. The through-hole conductor 33 is a vertical electrical connection path formed as a copper plating layer on the inner wall surface of the through-hole that penetrates the insulating layer 3.

  The manufacturing process of the communication module 10 is roughly as follows.

  First, a first partial laminate having a wiring pattern 26, a wiring layer 25, an insulating layer 5, and an interlayer connection conductor 35 (derived from conductive bumps printed by a conductive composition), a wiring layer 21, and a wiring layer 22 , Insulating layer 1, second partial laminate having interlayer connection conductor 31 (derived from conductive bump printed by conductive composition printing), wiring layer 23, wiring layer 24, insulating layer 3, through-hole conductor And a third partial stacked body having 33 are formed. The third partial laminate can be formed as a through-hole conductor 33 by forming a through hole in a normal double-sided copper-clad substrate and growing a copper plating layer on the inner wall surface thereof.

  An interlayer connection conductor 34 (conductive bump by conductive composition printing) and an insulating layer (prepreg stage) 4 are formed on the first partial laminate. In addition, an interlayer connection conductor 32 (conductive bump by conductive composition printing) and an insulating layer (prepreg stage) 2 are also formed on the third partial laminate. Thereafter, an opening is formed in the third partial laminate in accordance with the position of the component 41.

  On the second partial laminate, the component 41 is mounted at a predetermined position on the wiring layer 22 using solder 51. For this purpose, for example, the procedure of screen printing of cream solder to be the solder 51, placement of the component 41 by the mounter, and reflow of the cream solder can be adopted as in the case of normal component surface mounting.

  Thereafter, the second (lower), third (middle), and first (upper) partial laminates are stacked and pressed and heated with a press. As a result, the prepreg to be the insulating layer 2 and the prepreg to be the insulating layer 4 are completely cured, and the whole is integrated to obtain a laminate having five insulating layers. In this integration, due to the fluidity of each prepreg obtained by heating, each prepreg enters the space around the component 41 and the space inside the through-hole conductor 33 so that no gap is generated. The wiring layers 22 and 24 are electrically connected to the interlayer connection conductors 32 and 34, respectively.

  Thereafter, layers of solder resists 61 and 62 are formed on both sides of the laminate. Further, an electrical / electronic component such as the component 71 is mounted by executing a normal surface mounting process using the solder 81 to finish the communication module 10 as shown in FIG. In addition, about the wiring patterns 21 and 26 of the front and back, the patterning can also be performed after the whole lamination | stacking. Further, it is appropriate to perform Ni / Au plating treatment on the front surface of the wiring patterns 21 and 26 on the front and back surfaces so that the solder resists 61 and 62 are not formed thereon so as to be suitable for solder connection.

  If the above-described component built-in wiring board is used as the wiring board for configuring the communication module 10, the component mounting area can be saved, so that a smaller communication module can be obtained. This is convenient for downsizing the applied equipment and is valuable in that respect.

  FIG. 3 is a component layout diagram of external mounting / internal mounting of the wiring board included in the communication module 10 shown in FIG. The upper drawing shows the component layout for external mounting, and the lower drawing shows the built-in component layout. The size of the wiring board is 8.8 mm × 9.5 mm. The maximum thickness after all components are mounted on this wiring board is 1.65 mm. As shown in FIG. 3, the communication module using this wiring board has been greatly reduced in size as a whole due to the built-in components and high-density mounting on the outer surface. Regardless of this, there is an advantage that it is possible to cope with changes in the characteristics of antennas that can be connected.

  FIG. 4 is a table showing a design example of a matching circuit when the communication module 10 shown in FIG. 1 is applied to each antenna having different characteristics. Here, two cases are shown as the antenna 17 having the form and characteristics shown in the figure. The form such as the number of windings of the antenna 17 is generally determined according to the communication performance required by the device to be applied and the installation space prepared. Further, characteristics such as the equivalent series resistance of the antenna 17 are identified by using an antenna manufactured based on the determined form, and generally using a measuring instrument such as a network analyzer.

  As described above, the EMC filter component constant is determined so that the cut-off frequency is set on the outer side in consideration of the bandwidth of the frequency band to be used. Similarly, the component constant of the matching circuit is determined so that the power matching with the antenna 17 is sufficient. Specifically, it can be easily determined using a Smith chart.

  As a result, as shown in FIG. 4, in the case of antenna # 1, C3 (C5) and C4 (C6) are constants that require 33 pF, and in the case of antenna # 2, similarly, 60 pF is required. It is a constant. Therefore, here, C3 (C5) = 33 pF is used as the built-in capacitor, and C4 (C6) is set to 0 pF (uses dummy parts or no parts are mounted) when antenna # 1 is used, and antenna # 2 is used. In this case, it is 27 pF. In this case, C3 (C5) may be a value smaller than 33 pF.

  Further, as shown in FIG. 4, in the case of antenna # 1, C7 (C9) and C8 (C10) are constants that require 101 pF (≈100 pF), and in the case of antenna # 2, similarly, it is 253 pF. (≈250 pF) is a necessary constant. Therefore, here, C7 (C9) = 33 pF is a built-in capacitor, and C8 (C10) is 68 pF when antenna # 1 is used, and 220 pF when antenna # 2 is used. In this case, C7 (C9) is not 33 pF but may be another constant of 100 pF or less.

  As for R1 (R2), as shown in FIG. 4, in the case of antenna # 1, R1 (R2) is a constant that requires 3Ω, and in the case of antenna # 2, R1 (R2) is 0Ω ( (Use dummy parts) is a necessary constant. Here, since R1 (R2) is a component mounted on the outer surface, a necessary number of components are mounted on the outer surface in accordance with the connected antenna.

  1, 2, 3, 4, 5 ... insulating layer, 10 ... communication module (reader / writer circuit module), 11 ... communication processing IC (data processing IC for data read / write), 12 ... crystal component, 13 ... power supply component, 14 ... Other parts, 15 ... EMC filter, 16 ... Matching circuit, 17 ... Antenna, 21 ... Wiring layer (outer layer wiring pattern), 22, 23, 24, 25 ... Wiring layer (inner layer wiring pattern), 26 ... Wiring layer ( Outer layer wiring pattern), 31, 32 ... interlayer connection conductor (derived from conductive bumps printed by conductive composition), 33 ... through-hole conductor, 34,35 ... interlayer connection conductor (conductivity by printing conductive composition) 41 ... Surface mount type passive component (built-in component), 51 ... Solder, 61,62 ... Solder resist, 71 ... Surface mount type passive component (External surface) Parts), 81 ... solder.

Claims (3)

A wiring board;
A communication processing IC provided on the wiring board;
A matching circuit electrically connected to the communication processing IC and provided on the wiring board for matching with an antenna provided outside,
The matching circuit is a first capacitance element that is a capacitance element connected in series from the communication processing IC, and a capacitance element that is connected between a node that passes through the first capacitance element and the ground. A circuit of a passive element network comprising a second capacitance element and a resistance element, one end of which is connected to the node and the other end of which is connected to an antenna ;
The first capacitance element was formed by parallel connection of a surface mount type first capacitor built in the wiring board and a surface mount type second capacitor mounted on the surface of the wiring board. Circuit element,
The second capacitance element was formed by parallel connection of a surface mount type third capacitor built in the wiring board and a surface mount type fourth capacitor mounted on the surface of the wiring board. Circuit element,
The resistance element is a series connection of a surface mount type first resistor built in the wiring board and a surface mount type second resistor mounted on the surface of the wiring board. Communication module.   The communication module according to claim 1, wherein the communication processing IC generates a transmission signal in a 13.56 MHz frequency band toward the antenna through the matching circuit. A wiring board; a communication processing IC provided in the wiring board; and a matching circuit that is electrically connected to the communication processing IC and is provided in the wiring board to match an antenna provided outside. The matching circuit is connected between a first capacitance element that is a capacitance element connected in series from the communication processing IC, and a node that passes through the first capacitance element and a ground. Circuit of a passive element network comprising a second capacitance element, which is a capacitance element, and a resistance element, one end of which is connected to the node and the other end of which is connected to an antenna. , and the first capacitance element, a first capacitor surface mount type which is built in the wiring board, A circuit element formed by parallel connection with a surface mount type second capacitor mounted on the surface of the wiring board, wherein the second capacitance element is a surface mount type first element built in the wiring board. 3 is a circuit element formed by parallel connection of a capacitor 3 and a surface mount type fourth capacitor mounted on the surface of the wiring board, and the resistance element is a surface mount type built in the wiring board. A reader / writer circuit module which is a series connection of the first resistor and a surface mount type second resistor mounted on the surface of the wiring board ;
An reader / writer comprising: an antenna connected to the matching circuit of the reader / writer circuit module.

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