Reader

Abstract

To achieve a higher gain of an antenna while achieving a smaller size of a device.SOLUTION: A reading device includes an antenna element, a substrate having a communication circuit that transmits and receives a wireless signal to and from an RFID tag, a connecting member that electrically connects the communication circuit and the antenna element, a housing, a control unit that controls the communication circuit, a battery, and a power supply unit that supplies power from the battery to the communication circuit and the control unit. In a horizontal direction that is horizontal to the surface of the substrate having the communication circuit, the distance between a power feeding point where the connecting member contacts the antenna element and the communication circuit is shorter than the distance between the power feeding point and the control unit.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a reading device that performs wireless communication with a wireless device such as an RFID tag.

Background Art

[0002] Conventionally, a reading device such as an RFID reader that reads information by wireless communication from a wireless device such as an RFID (Radio Frequency Identification) tag attached to a management target such as a person or an object is known. Patent Document 1 describes that in a handy type RFID reader used by a user, a coaxial cable connecting an RFID substrate and an antenna is arranged such that a part thereof extends along a main substrate. According to this document, the gain of the antenna in the longitudinal direction of the main substrate is improved by using the ground of the main substrate as the virtual ground of the antenna.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The RFID reader is desired to be miniaturized according to the purpose of use. On the other hand, the RFID reader may include components such as a battery other than the RFID substrate and an external communication unit that performs wireless communication with an object different from the RFID tag. However, when miniaturized, the distance between the RFID substrate and each member becomes short, and it may be difficult to achieve a high gain of the antenna.

[0005] Therefore, an object of the present invention is to provide a reading device capable of achieving a high gain of an antenna while suppressing an increase in the size of the device.

Means for Solving the Problems

[0006] One aspect of the present invention is a reading device comprising: an antenna element; a substrate having a communication circuit that transmits and receives wireless signals with an RFID (Radio Frequency Identification) tag via the antenna element; a connecting member protruding from the substrate in the thickness direction of the substrate and electrically connecting the communication circuit and the antenna element; a housing that holds the antenna element, the substrate and the connecting member; a control unit that controls the communication circuit; a battery; and a power supply unit that supplies power from the battery to the communication circuit and the control unit, wherein, in a horizontal direction parallel to the surface of the substrate having the communication circuit, the distance between the power supply point where the connecting member contacts the antenna element and the communication circuit is shorter than the distance between the power supply point and the control unit. [Effects of the Invention]

[0007] According to the present invention, it is possible to achieve miniaturization while increasing the gain of the antenna. [Brief explanation of the drawing]

[0008] [Figure 1] A block diagram showing the configuration of the RFID reader according to Example 1. [Figure 2] Figures (a, b) illustrating an example of using the RFID reader according to Example 1. [Figure 3] A diagram showing the arrangement of the main components of the RFID reader according to Example 1. [Figure 4] A perspective view of the main components of the RFID reader according to Example 1. [Figure 5] Side view of the main components of the RFID reader according to Example 1. [Figure 6] Cross-sectional view of the RFID reader according to Example 1. [Figure 7] A diagram showing the electromagnetic wave radiation characteristics of the RFID reader according to Example 1. [Figure 8] Six-view drawings (a-e,g) and a cross-sectional view (f) of the RFID reader according to Example 1. [Figure 9] Exploded view of the RFID reader according to Example 1. [Figure 10] Exploded view of the RFID reader according to Example 1. [Figure 11] Figures (a, b) showing the positional relationship between the front cover and the components in Example 1. [Figure 12] Figures (a, b) showing the positional relationship between the back cover and the components in Example 1. [Figure 13] Figures (a, b) show the method of joining the front cover and back cover according to Example 1. [Figure 14] A diagram showing the arrangement of the main components of the RFID reader according to Example 2. [Figure 15] Perspective views (a, b) of the RFID reader according to Example 3. [Figure 16] A cross-sectional view (a) and a magnified view (b) of a part thereof of the RFID reader according to Example 3. [Modes for carrying out the invention]

[0009] The embodiments relating to this disclosure will be described below with reference to the drawings.

[0010] In the following description, the thickness direction of the RFID reader 100 is defined as the X-axis direction. The Y-axis direction and the Z-axis direction are defined as directions perpendicular to the X-axis direction and mutually perpendicular to each other. In the embodiment described below, the RFID reader 100 has a thin, plate-like (tablet-like) external shape in which the dimension (thickness) in the X-axis direction is smaller than the height and width as viewed in the X-axis direction. The external shape of the RFID reader 100 is rectangular, with the Z-axis direction being the height direction (long side direction, up and down direction) and the Y-axis direction being the width direction (short side direction, left and right direction) as viewed in the thickness direction. However, the external shape and components of the RFID reader 100 are not limited to those described below and can be appropriately changed depending on the purpose of use. Depending on the specific configuration of the RFID reader 100, the axial direction in the in-plane direction perpendicular to the thickness direction (X-axis direction) can be changed.

[0011] The side (+X side) where the switch 131, which will be described later with respect to the X-axis direction, is arranged is defined as the front side of the RFID reader 100, and the opposite side (-X side) is defined as the back side of the RFID reader 100. With respect to the Z-axis direction, the side (+Z side) where the LED 130, which will be described later, is arranged is defined as the upper side of the RFID reader 100, and the opposite side (-Z side) is defined as the back side of the RFID reader 100. Also, when the RFID reader 100 is viewed from the front side with the upper surface of the RFID reader 100 facing the upper side in the vertical direction (gravity direction), the right side (+Y side) is defined as the right side of the RFID reader 100, and the opposite side (-Y side) is defined as the left side of the RFID reader 100.

[0012] Also, the "RFID reader" shall include an RFID reader / writer having a function of reading information from a wireless device such as an RFID tag and a function of writing information to the wireless device.

[0013] 1. Example 1 1.1. Basic configuration of the RFID reader First, the components and functions of the RFID reader 100 according to Example 1 will be described with reference to FIG. 1. FIG. 1 is a block diagram illustrating the electrical configuration of the RFID reader 100.

[0014] As shown in FIG. 1, the RFID reader 100 includes an antenna unit 115 and an RF communication unit 120 that performs wireless communication with a wireless device such as an RFID tag 200 via the antenna unit 115. The RFID reader 100 also includes an arithmetic unit 101, a storage unit 102, a data communication unit 103, an external interface (I / F) 104, a charging unit 105, a battery 106, a power supply unit 107, a measurement unit 108, an LED 130, and a switch 131.

[0015] The antenna unit 115 and the RF communication unit 120 constitute a detection means (reading means, communication means) for detecting the RFID tag 200 and reading information from the RFID tag 200. The RFID reader 100 emits electromagnetic waves from the antenna unit 115. The RF communication unit 120 is provided on a substrate 150, which will be described later, and is a communication circuit that transmits and receives wireless signals via the antenna unit

[0016] The RFID tag 200 is a passive tag that incorporates a small IC chip, memory, and antenna, and stores identification information and other information that identifies the tag in its memory. The IC chip inside the RFID tag 200 is activated by electromagnetic waves emitted by the RFID reader 100, and the ID information is transmitted using the energy of the electromagnetic waves by being carried on the reflected electromagnetic waves from the RFID reader 100.

[0017] The RFID reader 100 can read ID information from the RFID tag 200 by detecting electromagnetic waves from the RFID tag 200 via the antenna unit 115.

[0018] The frequency of the electromagnetic waves used for communication between the RFID reader 100 and the RFID tag 200 is not particularly limited, but for example, radio waves in the UHF band can be used. The RFID reader 100 and the RFID tag 200 can communicate at a distance of several meters (within the reading range).

[0019] The arithmetic unit 101 and the storage unit 102 function as a control unit (controller) that controls the operation of the RFID reader 100. The arithmetic unit 101 is, for example, a CPU (Central Processing Unit). The storage unit 102 includes ROM (Read Only Memory) as non-volatile memory and RAM (Random Access Memory) as volatile memory. The ROM stores, for example, a program that defines the operating procedure of the RFID reader 100 and data collected by the RFID reader 100.

[0020] The arithmetic unit 101 controls the operation of each part of the RFID reader 100 by executing a program read from ROM using RAM as the workspace. For example, the arithmetic unit 101 causes the RF communication unit 120 to read RFID tags within the reading range, and stores the read information and reading time as reading result data in the storage unit 102. In parallel with reading the RFID tags, the arithmetic unit 101 measures the amount of movement of the RFID reader 100 based on the measurement results of the measurement unit 108, and stores the measured amount of movement and measurement time as measurement result data in the storage unit 102. Then, the arithmetic unit 101 transmits the reading result data and measurement result data stored in the storage unit 102, along with the identification information of its own device, to the management server via the data communication unit 103. Note that a single-chip microcontroller integrating the arithmetic unit 101 and the storage unit 102 may also be used.

[0021] By temporarily storing data in the memory unit 102 and transmitting it to an external device in a timely manner via the data communication unit 103, the frequency of communication between the RFID reader 100 and the external device can be reduced, thereby lowering the power consumption of the RFID reader 100. Furthermore, even when the RFID reader 100 cannot communicate with an external device, information can be temporarily stored in the memory unit 102.

[0022] The calculation unit 101 has a timer 121 that sets the operating period of the RFID reader 100. The timer 121 can count multiple times in parallel, acting as a time timer or a timer that determines the elapsed time of a predetermined period.

[0023] The measurement unit 108 can measure the relative movement of the RFID reader 100 and data of the environment in which the RFID reader 100 is placed, and output the measured data to the calculation unit 101. The measurement unit 108 in this embodiment includes an acceleration / gyro sensor 108a, a geomagnetic sensor 108b, and a barometric pressure sensor 108c. The acceleration / gyro sensor 108a measures the acceleration applied to the RFID reader 100 in the device coordinate system unique to the RFID reader 100 and outputs acceleration data. The acceleration / gyro sensor 108a also measures the angular velocity of the RFID reader 100, i.e., the change in the attitude of the RFID reader 100, and outputs angular velocity data. The geomagnetic sensor 108b measures the orientation of the RFID reader 100 in real space and outputs orientation data. The barometric pressure sensor 108c measures the atmospheric pressure in the space in which the RFID reader 100 is placed and outputs barometric pressure data.

[0024] The measurement unit 108 can measure the relative movement of the RFID reader 100 by accumulating the acceleration while converting the direction of the acceleration of the RFID reader 100 to a direction in a real-space coordinate system, based on the data from the sensor. This measurement of movement may be performed according to any known self-position estimation method. The relative movement output from the measurement unit 108 to the calculation unit 101 may be a two-dimensional vector in a plane parallel to the ground plane (floor) of the target area, or it may be a three-dimensional vector that also includes a component in the height direction. The reference position for measuring the relative movement may be, for example, the position of the RFID reader 100 when the RFID reader 100 is activated.

[0025] Although Figure 1 shows an example in which the RFID reader 100 includes a measuring unit 108, the measuring unit 104 may be included in an external device that is capable of communicating with the RFID reader 100 and is carried by the user together with the RFID reader 100. In that case, the RFID reader 100 receives movement amount information from the external device that indicates the relative amount of movement measured by the measuring unit 108.

[0026] The type of sensor placed in the measurement unit 108 can be changed according to the intended use of the RFID reader 100. Furthermore, when the RFID reader 100 is used in a fixed position in real space, the RFID reader 100 may be configured without the measurement unit 108.

[0027] The RF communication unit 120 is an electronic circuit controlled by the calculation unit 101 that transmits and receives electromagnetic waves to and from the RFID tag 200 via the antenna unit 115. The RF communication unit 120 includes an RF control unit 110, a power amplifier 111, a filter 112, a first coupler 113, a second coupler 114, an RF power detection unit 116, and a carrier cancellation unit 117.

[0028] The RF control unit 110 outputs a transmission signal (for example, a signal modulated in the UHF band) from the TX terminal to the power amplifier 111 according to instructions from the calculation unit 101. The power amplifier 111 amplifies the transmission signal input from the RF control unit 110 and outputs it to the filter 112. The filter 112 removes unwanted low-frequency components from the transmission signal after amplification by the power amplifier 111. The power of the RF output can be changed according to instructions from the calculation unit 101.

[0029] The first coupler 113 distributes the transmitted signal that has passed through the filter 112 to the coupler 114 and the power detection unit 116. The second coupler 114 outputs the transmitted signal input from the first coupler 113 to the antenna unit 115, and outputs the received signal input from the antenna unit 115 to the RF control unit 110. Alternatively, instead of the second coupler 114, a circulator may be used to separate the path for sending the transmitted signal from the first coupler 113 to the antenna unit 115 from the path for sending the received signal received by the antenna unit 115 to the RF control unit 110.

[0030] The antenna unit 115 has at least one antenna element. The antenna unit 115 radiates the transmission signal input from the second coupler 114 as an electromagnetic wave around the RFID reader 100. The antenna unit 115 also receives the signal returned from the RFID tag 200 and outputs the received signal to the second coupler 114.

[0031] The power detection unit 116 detects the power level of the signal input from the first coupler 113 and outputs a signal (RF_Detection) indicating the detected power level to the calculation unit 101. The carrier cancellation unit 117 cancels the carrier component of the received signal received by the antenna unit 115 via the second coupler 114 (Carrier Cancellation) based on the signal received from the calculation unit 101. As a result, the RF control unit 110 inputs the desired signal component of the received signal at the RX terminal. The RF control unit 110 demodulates the signal input from the RX terminal, obtains the ID information and other information returned from the RFID tag 200, and outputs the obtained information to the calculation unit 101.

[0032] The data communication unit 103 is a connection means (external communication unit) for connecting the RFID reader 100 to an external device (an object other than the RFID tag 200) in a communicative manner. The data communication unit 103 may be, for example, a wireless module unit that performs Bluetooth® communication, or a wireless module that performs Wi-Fi communication. The data communication unit 103 may also be a WLAN interface for communicating with a WLAN (Wireless Local Area Network) access point, or a cellular communication interface for communicating with a cellular base station. Furthermore, the data communication unit 103 may be a connection interface for connecting to a relay device (for example, a terminal owned by the user).

[0033] The external I / F 104 is a communication interface for wired connection between the RFID reader 100 and an external device. The RFID reader 100 can perform firmware updates via communication through the external I / F. In this embodiment, the external I / F 104 also serves as an interface connected to a power line to receive power for charging the battery 106. The external I / F 104 is, for example, a USB (Universal Serial Bus) connector (USB port).

[0034] The charging unit 105 is a circuit for charging the battery 106. The charging unit 105 has a charging IC (charging control IC) that controls the voltage and current supplied to the battery 106 while monitoring the state of the battery 106. The charging unit 105 charges the battery 106 using power supplied from an external source via the external I / F 104.

[0035] The battery 106 is a rechargeable and reusable secondary battery, such as a lithium-ion battery. The power supply unit 107 is a circuit that has a DC-DC converter and the like, and receives power from the battery 106 to supply power voltage to each part of the RFID reader 100.

[0036] The LED (Light Emitting Diode) 130 is a display means for notifying the external system of the status of the RFID reader 100. The LED 130 is controlled to light up and turn off by the calculation unit 101. A multicolor LED chip capable of emitting light of multiple colors and having multiple LEDs may be used as the display means. For example, the LED 130 lights up green when in use, amber when charging, and turns off when the power is off.

[0037] Switch 131 is an operating unit for switching the operating state of the RFID reader 100 from an external source. Switch 131 is a tact switch that operates when the button (131B), described later, is pressed by the user. For example, the user can turn the power of the RFID reader 100 on / off by pressing and holding switch 131, and perform a firmware reset by pressing and holding it again. In addition, by pressing switch 131, the user may instruct the RFID reader 100 to start or stop reading RFID tags 200, or to switch to power-saving mode.

[0038] The calculation unit 101 interprets the user's operation based on the current operating state of the RFID reader 100 and the operation method of the switch 131 (including the length of time and number of times it is pressed). However, the operating state of the RFID reader 100 is not limited to this. In addition, there may be an operation unit that accepts user operations on the RFID reader 100 instead of, or separately from, the switch 131.

[0039] 1.2. Examples of RFID reader usage The RFID reader 100 can constitute an RFID system that enables the determination of the location of an object in real space based on the results of reading identification information from RFID tags distributed at multiple locations. The object of location determination may be, for example, the RFID tag itself, a person, animal or object to which the RFID tag is attached, an RFID reader that reads the identification information, a user who possesses the RFID reader, or a machine equipped with an RFID reader.

[0040] Examples of RFID reader 100 usage are shown in Figure 2(a, b). As shown in Figure 2(a), in this example, the user carries the RFID reader 100 in a pocket of their clothing. As shown in Figure 2(b), an RFID tag 200 (referred to as an item tag) is attached to each item to be managed (in this case, an item). In addition, an RFID tag 200 (location tag, reference tag) that serves as a reference for location information is placed at a specific location within the building.

[0041] The RFID reader 100 calculates the amount of movement from the time the location tag was detected based on the measurement results of the measurement unit 108, and can determine the reader's current position as its relative position to the location tag. Furthermore, the RFID reader 100 can acquire location information for multiple items dispersed in real space by associating its current position at the time the item tag was detected with the ID information of the item tag.

[0042] The RFID reader 100 can provide the location information of an item to an external information processing device via the data communication unit 103. Alternatively, the RFID reader 100 itself can be equipped with a display device such as a liquid crystal panel to display the location information of an item acquired by the reader or another reader connected to it in a communicative manner.

[0043] Note that the example shown in Figure 2(a, b) is just one example, and the configuration of an RFID system that can use the RFID reader 100 is not limited to this. For example, instead of the RFID reader 100 being carried by the user, it may be mounted on a mobile machine (e.g., a drone, vehicle, or robot). Alternatively, for example, the RFID reader 100 may be fixed at a predetermined location in the physical space, and a system may be configured to determine the location of a managed object moving in the physical space by detecting the RFID tag 200 attached to the managed object.

[0044] The RFID tag 200 is an example of a wireless device whose information can be read by the RFID reader 100. The wireless device may also be an active type RFID tag. If the wireless device actively (for example, periodically) transmits information to its surroundings using power from a battery built into the wireless device itself, the device may be called a beacon tag. The wireless device may also be called by names such as IC tag, IC card, or responder. Furthermore, the information that the RFID reader 100 reads from the wireless device is not limited to ID information, but may be other types of information.

[0045] 1.3. Planar arrangement of components Next, the features of this embodiment will be described. In this embodiment, most of the components of the RFID reader 100 shown in Figure 1 are arranged on a single substrate. The external shape of the substrate 150 and the arrangement of the main components of the RFID reader 100 will be described using Figures 3 to 5. Figure 3 is an arrangement diagram showing the arrangement of the main components of the RFID reader 100, and represents the view of the substrate 150 etc. from the front side (+X side) in the thickness direction of the RFID reader 100. Figure 4 is a perspective view of the main components of the RFID reader 100. Figure 5 is a side view of the main components of the RFID reader 100 viewed from the right side (+Y side).

[0046] As shown in Figure 3, the substrate 150 has a roughly rectangular shape with the vertical direction (Z-axis direction) as the longer side and the horizontal direction (Y-axis direction) as the shorter side. In Figure 3, the vertical center of the substrate 150 is represented by Z0, and the horizontal center of the substrate 150 is represented by Y0.

[0047] As shown in Figures 3 and 4, the LED 130 is positioned near the upper edge of the substrate 150. As will be described later, the light guide 130g (Figure 6(a)) that radiates the light emitted by the LED 130 to the outside is exposed to the outside of the housing 160 at the edges of the front portion 160F and the top portion 160U of the housing 160 of the RFID reader 100. Therefore, it is preferable to position the LED 130 near the exposed portion of the light guide 130g.

[0048] The antenna section 115 of this embodiment transmits and receives radio waves, and is composed of a fed antenna element 115f and a passive antenna element 115p. Each antenna element can be made of a phosphor bronze base material with Ni+Au plating applied to its surface to provide corrosion resistance and reduce contact resistance. Each antenna element is attached to the inner surface of the housing 160, for example, with double-sided tape.

[0049] The feed antenna element 115f is connected to the RF communication unit 120 on the substrate 150 via a contact pin 125f as a connecting member, passive elements such as capacitors, inductors, and resistors (not shown) connected to the contact pin 125f, and a feed line 155 consisting of a conductor pattern formed on the substrate 150. The contact pin 125f and the feed line 155 constitute a transmission line for transmitting signals between the feed antenna element 115f and the RF communication unit 120. The feed antenna element 115f is a feed element that receives power from the RF communication unit 120 and radiates electromagnetic waves.

[0050] The unpowered antenna element 115p is connected to the ground plane of the circuit board 150 via a contact pin 125p and passive elements (not shown) such as capacitors, inductors, and resistors connected to the contact pin 125p. The unpowered antenna element 115p does not receive power directly from the RF communication unit 120, but resonates with the electromagnetic waves radiated by the fed antenna element 115f, thereby radiating electromagnetic waves together with the fed antenna element 115f. Both the fed antenna element 115f and the unpowered antenna element 115p function as receiving antennas.

[0051] Furthermore, contact pins 125f and 125p are connected to the power supply line 155 or ground plane of the circuit board 150 via passive elements such as capacitors, inductors, and resistors.

[0052] The substrate 150 has a ground plane (GND layer). The ground plane is formed as a conductive thin film pattern such as copper foil. The ground plane becomes the reference potential for the voltage applied to the feed antenna element 115f at the feed point FP. The substrate 150 used in this embodiment is a laminated substrate and has multiple ground plane layers. In Figure 5, the symbol “GND” indicates the ground plane formed on the surface layer of the substrate 150.

[0053] Of the ground plane of the circuit board 150, the area facing the antenna section 115 (the area above the switch 131 and power supply section 107) functions as part of the antenna. Therefore, it is desirable not to place electronic components around the antenna section 115.

[0054] The antenna section 115 is preferably composed of a planar element that extends substantially perpendicular to the X-axis direction (the thickness direction of the RFID reader 100). In this embodiment, the fed antenna element 115f and the unfed antenna element 115p each extend substantially perpendicular to the X-axis direction and have an L-shaped bend when viewed from the front side in the X-axis direction. In this embodiment, the fed antenna element 115f and the unfed antenna element 115p have a left-right symmetrical shape with respect to the central position Y0 in the left-right direction.

[0055] In this embodiment, the antenna portion 115 is positioned above the vertical center position Z0 of the substrate 150. Also in this embodiment, the feed point FP of the fed antenna element 115f is provided at the lower end of the fed antenna element 115f. Furthermore, the contact point between the unfed antenna element 115p and the contact pin 125p, which will be described later, is also provided at the lower end of the unfed antenna element 115p. That is, the antenna portion 115 extends upward from the contact point with the substrate 150.

[0056] The illustrated configuration of the antenna section 115 is an example, and the shape and arrangement of the antenna elements constituting the antenna section 115 can be changed according to the required directivity and polarization. For example, the fed antenna element 115f and / or unfed antenna element 115p may be further divided into multiple elements, or the antenna section 115 may be composed of a single antenna element. The antenna element may be, for example, a rectangular planar antenna in the X-axis direction, or a linear antenna such as an inverted F antenna. Furthermore, as will be described later, the antenna section 115 in this embodiment has omnidirectional and circularly polarized characteristics, but it may also have directivity or linear polarization. In addition, the antenna section 115 may be configured to allow switching between directivity and polarization.

[0057] In this embodiment, all components of the RFID reader 100 shown in Figure 1, except for the LED 130, are arranged to be concentrated below the antenna section 115 in the vertical direction. In other words, in this embodiment, the communication circuit, the external communication section, the control section, the power supply section, and the battery are arranged to be concentrated on one side in the height direction relative to the antenna element and the passive antenna element. This arrangement allows the electronic components and the conductor patterns connecting the electronic components to each other on the substrate 150 to be kept away from the vicinity of the antenna section 115.

[0058] The switch 131 is positioned near the center Y0,Z0 in the vertical and horizontal directions of the circuit board 150. Because the switch 131 is positioned between two antenna elements in the horizontal direction, the antenna characteristics are not hindered by the placement of the switch 131. For example, there is no need to change the shape of the antenna elements to avoid the switch 131 and the button assembly 131B described later. In addition, because the switch 131 is positioned in the center of the RFID reader 100, the user can easily operate the switch 131.

[0059] The RF communication unit 120 is positioned below the vertical center position Z0 of the substrate 150. Furthermore, the area occupied by the RF communication unit 120 in the vertical direction at least partially overlaps with the area occupied by the battery 106 in the vertical direction. The RF communication unit 120 is positioned to the right of the battery 106.

[0060] In other words, the side on which the RF communication unit 120 is located in the left-right direction is the same as the side on which the powered antenna element 115f, which receives power from the RF communication unit 120, is located (right side, +Y side). To put it another way, the antenna element and the unpowered antenna element are arranged side by side in the width direction, and the communication circuit is located on the same side as the antenna element in the width direction. Therefore, the loss of transmitted or received signals in the power supply line 155 extending from the RF communication unit 120 to the power supply point FP of the powered antenna element 115f can be reduced. Note that in the actual circuit board 150, it is not necessary to form the power supply line 155 in the path shown in Figure 3, and the path is designed considering the positional relationship with other electronic components and the relationship with the wavelength of electromagnetic waves used for transmission and reception with the RFID tag 200.

[0061] Furthermore, in this embodiment, a feed point FP is provided at the lower end of the feed antenna element 115f, and an element (second coupler 114) connected to the feed point FP via the feed line 155 is positioned at the top of the RF communication unit 120. This further reduces losses in the feed line 155.

[0062] Here, the feeding distance Df is defined as the distance (straight-line distance in the YZ plane) from the feeding point FP of the feeding antenna element 115f to the element (second coupler 114 in this embodiment) that applies high frequency to the feeding point FP via the feeding line 155 within the RF communication unit 120. Here, the YZ plane is the horizontal plane that is horizontal to the surface of the substrate having the communication circuit.

[0063] In this embodiment, the power supply distance Df is shorter than the distance from the power supply point FP to the calculation unit 101 (control unit). Therefore, the influence of electromagnetic noise emitted by the calculation unit 101 (control unit) on the transmission and reception of signals via the power supply line 155 can be reduced. Also, the power supply distance Df is shorter than the distance from the power supply point FP to the data communication unit 103. Therefore, the influence of electromagnetic waves emitted by the data communication unit 103 during communication on the transmission and reception of signals via the power supply line 155 can be reduced. Also, the power supply distance Df is shorter than the distance from the power supply point FP to the power supply unit 107. Therefore, the influence of electromagnetic noise emitted by the DC-DC converter, etc., of the power supply unit 107 on the transmission and reception of signals via the power supply line 155 can be reduced. Thus, in this embodiment, the distance (Df) between the power supply point and the communication circuit on the substrate is shorter than the distance between the power supply point and the control unit, the distance between the power supply point and the external communication unit, and the distance between the power supply point and the power supply unit.

[0064] At least a portion (preferably the whole) of the RF communication unit 120 is covered by a shielding plate 153. Covering the RF communication unit 120 with the shielding plate 153 reduces the reception of electromagnetic waves from the RFID tag 200 or electromagnetic noise from outside or inside the device by the RF communication unit 120 through a path other than the antenna unit 115. The shielding plate 153 is, for example, a tin plate and is mounted on the substrate 150 by soldering.

[0065] The measurement unit 108 is positioned below the RF communication unit 120, near the central position Y0 of the substrate 150 in the left-right direction. In the up-down direction, the measurement unit 108 is positioned on the opposite side of the antenna unit 115 from the RF communication unit 120, thus reducing the possibility of electromagnetic waves radiated by the antenna unit 115 interfering with the sensors of the measurement unit 108. In other words, the distance between the power supply point and the communication circuit on the substrate is shorter than the distance between the power supply point and the measurement unit, thus reducing the possibility of electromagnetic waves radiated by the antenna unit 115 interfering with the measurement unit.

[0066] The geomagnetic sensor 108b of the measurement unit 108 is positioned in a GND-less region (dashed line in Figure 3) on the substrate 150 where a ground plane is not formed, so that it can accurately detect the Earth's magnetic field. On the other hand, in order to reduce the influence of electromagnetic noise from outside the device and to reduce the radiation of electromagnetic noise to the outside of the device, it is desirable to position the ground plane so as to surround the outer periphery of the substrate 150. In this embodiment, the measurement unit 108 is positioned near the center in the left-right direction, and below the RF communication unit 120 and above the storage unit 102 and external I / F 104 in the vertical direction, so that the GND-less region for the sensor does not overlap with the ground plane on the outer periphery of the substrate.

[0067] The data communication unit 103 is located at the lower end of the circuit board 150. Since the data communication unit 103 is located on the opposite side of the antenna unit 115 in the vertical direction, electromagnetic interference between the data communication unit 103 and the antenna unit 115 can be reduced.

[0068] The external interface 104 is located at the lower end of the circuit board 150, near the center position Y0 in the left-right direction. The connector of the external interface 104 is exposed on the bottom surface of the housing 160 (Figure 8(g)). This allows the user to connect a charging cable to the external interface 104 and charge the RFID reader 100 in the same way as a smartphone.

[0069] The battery 106 is positioned on the opposite side of the antenna unit 115 in the vertical direction (i.e., on the lower side of the circuit board 150) and on the opposite side of the RF communication unit 120 in the horizontal direction (on the left side of the circuit board 150). The circuit board 150 is provided with an inverted L-shaped notch 159 (recess) to form a space for housing the battery 106. Since the battery 106 is one of the thicker components of the RFID reader 100, providing the notch 159 in the circuit board 150 makes it possible to make the entire RFID reader 100 thinner. More details will be described later using Figure 5.

[0070] Furthermore, the battery 106 is a component of the RFID reader 100 that is large in both height (vertical length) and width (horizontal length). By placing such a battery 106 on the opposite side of the RF communication unit 120 in the left-right direction, a wide ground plane can be secured on the side (right side) of the power supply antenna element 115f, thereby improving the antenna characteristics.

[0071] The power supply unit 107 and the charging unit 105 are positioned vertically between the antenna unit 115 and the battery 106, and horizontally on the same side as the battery 106 (left side of the circuit board 150). The power supply unit 107 is covered by a shielding plate 154 to suppress the radiation of switching noise from the DC-DC converter (Figure 4). The shielding plate 154 is, for example, a tin plate and is mounted on the circuit board 150 by soldering.

[0072] In this embodiment, the antenna element, the communication circuit, the control unit, and the external communication unit are arranged sequentially on the substrate from one side in the width direction toward the other side in the height direction. Furthermore, the passive antenna element, the power supply unit, and the battery are arranged sequentially on the substrate from one side in the width direction toward the other side in the height direction. This arrangement allows for efficient placement of components within the limited space of the housing while improving antenna performance.

[0073] 1.4. Component placement in the thickness direction Next, the arrangement of components in the thickness direction (X-axis direction) of the RFID reader 100 will be explained using Figures 5 and 6. Figure 6 is a cross-sectional view of the RFID reader 100 cut by a virtual plane perpendicular to the Y-axis direction.

[0074] As shown in Figures 4, 5, and 6, the antenna elements 115f and 115p of the antenna section 115 in this embodiment are spaced apart from the substrate 150 on one side (front side, +X side) in the thickness direction (X-axis direction) of the RFID reader 100.

[0075] The antenna elements 115f and 115p and the circuit board 150 are connected via contact pins 125f and 125p, which act as connecting members. The contact pins 125f and 125p are mounted on the circuit board 150 and protrude from the circuit board 150 on one side in the thickness direction (X-axis direction) (front side, +X side). On the other hand, the antenna elements 115f and 115p are held by the front cover 161 of the housing 160, which will be described later, and when the circuit board 150 is attached to the front cover 161, the antenna elements 115f and 115p come into contact with the contact pins 125f and 125p, respectively.

[0076] As shown in Figure 6, the distance in the thickness direction (X-axis direction) from the contact point (feed point FP) between the feed antenna element 115f and the contact pin 125f to the ground plane GND on the substrate 150 is defined as the first distance D1. If the substrate 150 has multiple layers of ground planes, the distance from the feed point FP to the nearest ground plane is defined as the first distance D1. The distance in the thickness direction (X-axis direction) from the back surface 150b of the substrate 150 to the inner surface 162i of the back surface 160B (first surface) of the housing 160 is defined as the second distance D2. If there are protrusions such as reinforcing ribs on the inner surface 162i of the back surface 160B, the second distance D2 is defined based on the inner surface 162i at a location without protrusions. In other words, the distance in the thickness direction from the feed point where the connecting member contacts the antenna element to the ground plane is defined as the first distance, and the distance in the thickness direction between the substrate and the first surface is defined as the second distance.

[0077] In this embodiment, a configuration is adopted in which the first distance D1 is greater than the second distance D2. In other words, the feed antenna element 115f, the substrate 150, and the rear portion 160B are arranged such that D1 > D2.

[0078] In one configuration example of this embodiment, the first distance D1 is 6.2 mm and the second distance D2 is 1.6 mm. The overall thickness of the housing 160 is approximately 13 mm. The overall thickness of the housing 160 is preferably 20 mm or less, and more preferably 10 mm to 15 mm. Furthermore, although the height (vertical width, dimension in the height direction) and width (horizontal width, dimension in the width direction) of the housing 160 are not particularly limited, it is preferable from a usability standpoint to make it a size that can be carried by a user in a clothing pocket, for example.

[0079] If an antenna element is placed on the substrate 150, the antenna element will be close to the ground plane GND of the substrate 150. In this case, the electromagnetic waves radiated by the antenna element will decrease, which may reduce the antenna gain.

[0080] In this embodiment, the antenna element 115f is positioned at a distance from the ground plane GND on the substrate 150, so that D1 > D2, thereby improving the antenna gain. In other words, according to this embodiment, it is possible to increase the antenna gain while suppressing an increase in the thickness of the device.

[0081] Furthermore, the relationship D1 > D2 described above also applies to the unpowered antenna element 115p. That is, the distance in the thickness direction from the contact point between the unpowered antenna element 115p and the contact pin 125p to the ground plane GND on the circuit board 150 is greater than the distance in the thickness direction from the back surface 150b of the circuit board 150 to the inner surface 162i of the back cover 162 of the housing 160.

[0082] The contact pins 125f and 125p are preferably, for example, spring pin type contacts (spring connectors). A spring pin type contact is a contact unit comprising a cylindrical body portion f1, a contact portion f2 held at the tip of the body portion, and a spring that biases the contact portion f2 toward protruding from the body portion f1. In this case, when the contact pins 125f and 125p come into contact with the antenna elements 115f and 115p, the contact portion f2 is pushed in against the biasing force of the spring. By using a spring pin type contact, component tolerances and assembly tolerances of the housing 160 and the substrate 150 can be absorbed, and electrical conductivity between the substrate 150 and the antenna elements 115f and 115p can be more reliably ensured.

[0083] Furthermore, a configuration in which an elastic conductor, such as a spring contact, directly contacts the antenna element is also possible. Alternatively, conductivity may be ensured by a slidable contact between a part of the antenna element and a part of the contact member on the substrate side. That is, by making at least one of the contacts on the substrate side or the contacts on the antenna element side a structure that can be elastically deformed in the thickness direction, or by making the contact portion between the contacts a slidable structure, conductivity between the substrate 150 and the antenna elements 115f, 115p can be more reliably ensured.

[0084] 1.5. Antenna Characteristics The radiation characteristics of the antenna section 115 in this embodiment will be explained using Figure 7. The radiation pattern shown in Figure 7 was measured using the so-called Standard Antenna Method. In the Standard Antenna Method, the antenna gain (relative gain) of the object being measured (in this case, the RFID reader 100) is measured by comparing it with an antenna whose gain is known in advance (standard antenna, reference antenna).

[0085] The measurement environment used is an anechoic chamber (or anechoic box) equipped with a turntable. A horn antenna is used as the standard antenna. For example, the measurement shown in Figure 7 used a measurement system combining a six-sided anechoic chamber, a horn antenna, a spectrum analyzer ESW26 (manufactured by ROHDE & SCHWARZ), and a signal generator N5171B (manufactured by Keysight). Note that the measurement equipment used in the measurement shown in Figure 7 can be any equipment capable of equivalent measurement, and is not limited to the equipment mentioned above.

[0086] The measurement procedure involves first setting up a standard antenna and a receiving antenna in an anechoic chamber, and having the standard antenna emit electromagnetic waves at the same frequency used by the RFID reader 100 for communication, while measuring the field strength E0 with the receiving antenna. Next, the RFID reader 100 is placed in the same location where the standard antenna was installed, and the RFID reader 100 is made to radiate electromagnetic waves while the field strength E is measured with the receiving antenna. If the gain of the standard antenna is G0, the gain G(dB) of the RFID reader 100 is expressed as G=G0+E-E0. To obtain the radiation pattern, the gain values ​​measured while rotating the turntable can be plotted on a circular graph. Furthermore, by using a horizontally polarized or vertically polarized antenna as the receiving antenna, the linearly polarized component of the electromagnetic waves radiated by the RFID reader 100 can be measured.

[0087] The top row of Figure 7 shows the horizontal polarization gain (left) and vertical polarization gain (right) of RFID reader 100 in a plane perpendicular to the Z-axis (XY plane). The middle row of Figure 7 shows the horizontal polarization gain (left) and vertical polarization gain (right) of RFID reader 100 in a plane perpendicular to the Y-axis (XZ plane). The bottom row of Figure 7 shows the horizontal polarization gain (left) and vertical polarization gain (right) of RFID reader 100 in a plane perpendicular to the X-axis (YZ plane).

[0088] As shown in the figures in Figure 7, the antenna section 115 of this embodiment has roughly the same gain in all directions on a spherical surface. Specifically, for horizontal polarization and vertical polarization, the difference between the maximum gain and minimum gain in the XY plane, XZ plane, and YZ plane is 30 dB or less. Therefore, stable communication can be achieved regardless of the position of the RFID tag 200 with respect to the RFID reader 100 as the center of the coordinate axis, or the relative orientation of the antenna element of the RFID tag 200 with respect to the RFID reader 100. Consequently, even when a user carries the RFID reader 100 and moves around, or when the RFID tag 200 is attached to a moving object, the RFID reader 100 can detect the RFID tag 200 more reliably.

[0089] The radiation characteristics of the RFID reader 100 can be changed depending on the intended use of the RFID reader 100 and the configuration of the RFID system. For example, if the orientation of the RFID tag 200 is limited, the RFID reader may have the omnidirectional properties described above for either horizontal or vertical polarization. Also, if it is known from the intended use of the RFID reader 100 that there is always an obstruction in a predetermined direction relative to the RFID reader 100, the RFID reader may have directivity with that direction as the null point.

[0090] 1.6. Enclosure Configuration Next, the housing configuration of the RFID reader 100 will be explained using Figures 8(a-f) to 13(a, b).

[0091] Figures 8(a-g) show a top view (a), rear view (b), left side view (c), front view (d), right side view (e), cross-sectional view (f), and bottom view (g) of the RFID reader 100 according to Embodiment 1. Figures 9 and 10 are exploded views of the RFID reader 100. Figure 11(a) is a view of the front cover 161 of the housing 160, to which the antenna elements 115f, 115p and light guide 130g are attached, as seen from the rear side (-X side). Figure 11(b) is a view of the front cover 161 of the housing 160, to which the button assembly 131B is further attached, as seen from the rear side (-X side). Figure 12(a) is a view of the circuit board 150, battery 106, and back cover 162 as seen from the front side (+X side). Figure 12(b) is a diagram showing Figure 12(a) with the addition of the antenna section 115, button assembly 131B, and shielding plates 153 and 154. Figures 13(a, b) are diagrams illustrating the method of joining the front cover 161 and the back cover 162.

[0092] As shown in Figures 8(a-g), 9, and 10, the housing 160 of the RFID reader 100 in this embodiment is composed of two components: a front cover 161 and a back cover 162. The front cover 161 is a substantially rectangular component that covers the substrate 150 from the front side (+X side) in the thickness direction, and constitutes the front portion 160F of the housing 160. The back cover 162 is a substantially rectangular component that covers the substrate 150 from the back side (-X side) in the thickness direction, and constitutes the back portion 160B of the housing 160.

[0093] The front cover 161 and the back cover 162 are made of a resin material that transmits electromagnetic waves emitted by the antenna section 115. Furthermore, since the dielectric constant and dielectric loss tangent values ​​of the housing 160 material affect the radio wave characteristics, it is desirable to optimize the shape of the antenna section 115 according to the materials of the front cover 161 and the back cover 162.

[0094] A slit 161s is provided on the front and upper edge of the front cover 161, into which a light guide 130g for the LED 130 is attached (see Figures 8(d, f) and 9). The light guide 130g is a component that guides the light emitted by the LED 130 to the light-emitting surface exposed to the outside of the housing 160. The light guide 130g is bonded to the front cover 161 while fitted into the slit 161s.

[0095] The button assembly 131B is fixed to the front cover 161 from the back side by means of screws or other methods (see Figures 8(d), 10, and 11(a, b)). The button assembly 131B has a cap portion b1 that is exposed to the outside of the housing 160 through a window portion 161a (Figure 10) provided in the front cover 161, and a base b2 that elastically supports the cap portion. When the user presses the cap portion b1, the cap portion b1 presses the switch 131 (Figure 9) on the circuit board 150.

[0096] An antenna icon Ic is provided on the front portion 160F of the front cover 161, in the left-right center and above the button assembly 131B (see Figure 8(d)). The antenna icon Ic makes it immediately clear that the RFID reader 100 is a device that emits electromagnetic waves, and also serves to prevent the user from holding the antenna portion 115 to shield the electromagnetic waves. The antenna icon Ic can be represented by the uneven shape formed on the front portion 160F of the front cover 161.

[0097] The back cover 162 has two strap holes 162h and 162i at the top and bottom (Figure 8 (a, b, g)). Users can attach a neck strap or arm strap to the strap holes 162h and 162i as needed.

[0098] Additionally, a label Lb is affixed to the back surface 160B of the back cover 162. Label Lb is a regulated rating plate and includes information such as the serial number and construction certification.

[0099] As shown in Figures 10(a, b) and 6, the antenna elements 115f and 115p of this embodiment are held on the inner surface 161i (inner surface of the housing) of the front cover 161 which constitutes the front portion 160F (second surface) of the housing 160. When the circuit board 150 is fixed to the front cover 161 by screwing or other means in this state, the tips of the contact pins 125f and 125p on the circuit board 150 contact the antenna elements 115f and 115p, and electrical conductivity is established between the circuit board 150 and the antenna portion 115 (see Figures 12(a, b)).

[0100] As shown in Figures 13(a, b), the front cover 161 and the back cover 162 are joined together with the circuit board 150 and other components sandwiched inside. For example, adhesive is applied to the outer peripheral region Adh (shaded area) shown in Figure 13(b), and the front cover 161 and the back cover 162 are bonded together. This makes the housing 160 difficult to disassemble.

[0101] As shown in Figures 6 and 8(f), in this embodiment, in the assembled state of the RFID reader 100, the antenna elements 115f, 115p and the circuit board 150 are held in the space between the front cover 161 and the back cover 162. Since the circuit board 150 is fixed to the front cover 161 by means of screws or the like, the possibility of damage due to impacts such as dropping is reduced.

[0102] In this embodiment, in order to ensure the distance between the antenna elements 115f, 115p and the ground plane GND on the substrate 150, the main components on the substrate 150 are concentrated on the same surface of the substrate 150, on the side facing the antenna elements (front side, +X side). Specifically, the calculation unit 101, storage unit 102, data communication unit 103, external I / F 104, charging unit 105, power supply unit 107 (shield plate 154), LED 130, switch 131, and RF communication unit 120 (shield plate 153) are all located on the front side of the substrate 150. Furthermore, the front surface of the substrate 150 is offset to the rear side (-X side) from the central position X0 of the housing 160 in the thickness direction (X axis direction) (Figure 6). This configuration makes it possible to improve antenna gain by ensuring the distance between the antenna elements 115f, 115p and the ground plane GND on the substrate 150 while suppressing an increase in the thickness of the housing 160.

[0103] Furthermore, in this embodiment, the battery 106 is the component with the largest thickness among the RFID reader 100 components, excluding the housing 160. A larger battery capacity reduces the frequency of charging the RFID reader 100, improving usability. In this embodiment, a notch 159 (Figure 3) is provided in the substrate 150 to match the shape of the battery 106, allowing the battery 106 and the substrate 150 to be positioned with overlapping thickness-direction occupancy areas (Figure 5).

[0104] In other words, the substrate 150 and the battery 106 overlap when viewed in any direction perpendicular to the thickness direction. This allows the housing 160 to be made smaller in the thickness direction compared to a configuration where the substrate 150 and the battery 106 are aligned in the thickness direction. The thickness (maximum thickness) of the battery 106 is greater than the first distance D1 and less than the sum of the first distance D1 and the second distance D2.

[0105] 2. Example 2 The RFID reader 100A according to Example 2 will be described with reference to Figure 14. Hereinafter, elements having substantially the same configuration and operation as those in Example 1 will be denoted by the same reference numerals as in Example 1, and the differences from Example 1 will be mainly described.

[0106] Figure 14 is a layout diagram showing the arrangement of components on the substrate 150 according to Embodiment 2. Figure 14 shows the view of the substrate 150 from the front side (+X side) in the thickness direction of the RFID reader 100A. The components of the RFID reader 100A according to this embodiment are the same as those of Embodiment 1 shown in Figure 1, except for the arrangement of components on the substrate 150.

[0107] As shown in Figure 14, the battery 106 is positioned horizontally in a notch 159A formed in the lower part of the circuit board 150, and the power supply unit 107 is positioned to the right of the battery 106 and at the bottom of the circuit board 150. The power supply unit 107 is covered by a shielding plate 154. In addition, the charging unit 105 is positioned adjacent to the upper side of the battery 106. By arranging the power-related components together at the bottom of the circuit board 150 in this way, wiring efficiency is improved, and the possibility of noise emitted by the power supply unit 107 interfering with the transmission and reception of electromagnetic waves via the antenna unit 115 can be reduced.

[0108] The RF communication unit 120 is located on the right side of the circuit board 150, below the antenna unit 115 and above the power supply unit 107. The RF communication unit 120 is covered by a shielding plate 153. The side on which the RF communication unit 120 is located is the same as the side (right side, +Y side) on which the powered antenna element 115f, which receives power from the RF communication unit 120, is located. Therefore, the loss of the transmitted or received signal in the feed line 155 extending from the RF communication unit 120 to the feed point FP of the powered antenna element 115f can be reduced.

[0109] In this embodiment as well, the feed distance Df from the feed point FP of the feed antenna element 115f to the second coupler 114 of the RF communication unit 120 is shorter than the distance from the feed point FP to the calculation unit 101, the data communication unit 103, and the power supply unit. Therefore, the possibility of electromagnetic waves (noise) generated from these components interfering with the transmission and reception of signals via the feed line 155 can be reduced.

[0110] The external interface 104 and the data communication unit 103 are located at the left end of the circuit board 150. In the vertical direction, the data communication unit 103 is located on the opposite side (below) of the antenna unit 115, with the external interface 104 in between. Therefore, the possibility of electromagnetic waves generated by the data communication unit 103 during communication interfering with the transmission and reception of signals via the antenna unit 115 can be reduced.

[0111] The arithmetic unit 101 and the storage unit 102 are positioned between the external interface and data communication unit 103 and the RF communication unit 120 in the left-right direction. In the up-down direction, the arithmetic unit 101 is positioned on the opposite side (below) of the antenna unit 115, with the storage unit 102 in between. Therefore, the possibility of electromagnetic noise generated by the arithmetic unit 101 interfering with the transmission and reception of signals via the antenna unit 115 can be reduced.

[0112] In this embodiment, the antenna element, the communication circuit, and the power supply unit are arranged sequentially on the substrate from one side in the width direction toward the other side in the height direction. Furthermore, the passive antenna element, the external communication unit, and the battery are arranged sequentially on the substrate from one side in the width direction toward the other side in the height direction. This arrangement allows for efficient placement of components within the limited space of the housing while improving antenna performance.

[0113] In this embodiment as well, the antenna elements 115f and 115p are positioned at a distance from the ground plane GND on the substrate 150 to achieve D1 > D2. This makes it possible to increase the antenna gain while suppressing an increase in the thickness of the device. Furthermore, according to this embodiment, the antenna section 115 and the circuit on the substrate 150 can be efficiently arranged in the limited space within the housing 160 using a different layout than in Embodiment 1.

[0114] 3. Example 3 The RFID reader 100B according to Example 3 will be described using Figures 15(a, b) and 16(a, b). Hereinafter, elements having substantially the same configuration and operation as those in Example 1 will be denoted by the same reference numerals as in Example 1, and the differences from Example 1 will be mainly described.

[0115] Figure 15(a, b) is a perspective view of the RFID reader 100B according to Embodiment 3. Figure 16(a) is a cross-sectional view of the RFID reader 100B in a plane perpendicular to the Y-axis direction, and Figure 16(b) is an enlarged view of a part of it.

[0116] As shown in Figures 15(a, b) and 16(a, b), in this embodiment, the antenna elements 115f and 115p of the antenna section 115 are arranged on the outside of the housing 160. The antenna elements 115f and 115p are fixed to the outer surface 161o (outer surface of the housing) of the front cover 161 which constitutes the front part 160F (second surface) of the housing 160 using double-sided tape or the like.

[0117] A hole 161b (Figure 16(b)) is formed in the front cover 161, penetrating in the thickness direction (X-axis direction). The contact pin 125f, which serves as a connecting member provided on the substrate 150, contacts the antenna element 115f through the hole in the front cover 161. Although Figures 16(a, b) illustrate the contact configuration of the fed antenna element 115f, the contact configuration of the unfed antenna element 115p is similar.

[0118] In this embodiment as well, antenna elements 115f and 115p are positioned at a distance from the ground plane GND on the substrate 150 to ensure that D1 > D2. This makes it possible to increase the antenna gain while suppressing an increase in the thickness of the device.

[0119] Furthermore, according to this embodiment, the first distance D1 can be made larger than in Embodiment 1 without increasing the overall thickness of the housing 160. That is, compared to Embodiment 1 (Figure 6), the first distance D1 can be made larger by the thickness of the front cover 161. As a result, if the overall thickness of the housing 160 remains constant, the antenna gain can be further improved by securing the first distance D1. In addition, the housing 160 can be made thinner while maintaining the antenna gain.

[0120] In this embodiment, the antenna elements 115f and 115p located on the outside of the housing 160 may be covered with a resin film of about several tens to several hundred micrometers in thickness to protect them from corrosion or damage. Alternatively, the antenna elements 115f and 115p may be covered with an opaque resin film to improve their appearance. Even if the antenna elements 115f and 115p are covered with a very thin resin film, the radiation characteristics of the antenna section 115 are substantially maintained. [Explanation of symbols]

[0121] 100 RFID readers 115f antenna element (powered antenna element) 115p unpowered antenna element 125f Connecting Member 120 Communication Circuit 150 circuit boards 160 cabinets 160B 1st side (back side) 160F 2nd side part (front part) D1 1st distance D2 2nd distance FP power supply point GND Ground Plane

Claims

1. Antenna element and A circuit board having a communication circuit that transmits and receives wireless signals to and from an RFID (Radio Frequency Identification) tag via the aforementioned antenna element, A connecting member protrudes from the substrate in the thickness direction of the substrate and electrically connects the communication circuit and the antenna element, A housing that holds the antenna element, the substrate, and the connecting member, A control unit that controls the communication circuit, Battery and A power supply unit that supplies power from the aforementioned battery to the communication circuit and the control unit, A reading device equipped with, In the horizontal direction parallel to the surface of the substrate having the communication circuit, the distance between the power supply point where the connecting member contacts the antenna element and the communication circuit is shorter than the distance between the power supply point and the control unit. A reading device characterized by the following.

2. The control unit comprises an external communication unit that performs wireless communication with an object other than the object of wireless communication via the antenna element, and the control unit controls the external communication unit. The reading device according to feature 1.

3. The distance between the power supply point and the communication circuit in the horizontal direction is shorter than the distance between the power supply point and the external communication unit, and the distance between the power supply point and the power supply unit. The reading device according to feature 2.

4. The communication circuit has a coupler that outputs an input transmission signal to the antenna element and receives a reception signal input from the antenna element. The distance between the power supply point and the communication circuit in the horizontal direction is the distance between the power supply point and the coupler in the horizontal direction. The reading device according to feature 2.

5. The communication circuit, the external communication unit, the control unit, and the power supply unit are all arranged together on the same surface of the substrate, on the side of the substrate facing the antenna element. The reading device according to feature 2.

6. The system further comprises a powerless antenna element that does not receive power from the aforementioned communication circuit, The housing has a plate-like outer shape in which the dimension in the thickness direction is smaller than the dimensions in the height direction and width direction when viewed in the thickness direction. The aforementioned antenna element and the aforementioned unpowered antenna element are arranged side by side in the width direction. The communication circuit is arranged on the same side as the antenna element with respect to the width direction. The reading device according to feature 5.

7. The communication circuit, the external communication unit, the control unit, the power supply unit, and the battery are arranged to be concentrated on one side in the height direction relative to the antenna element and the passive antenna element. The reading device according to feature 6.

8. The device further includes a measuring unit provided on the substrate for measuring the amount of movement of the reading device or information about the environment in which the reading device is located. The distance between the power supply point and the communication circuit on the substrate is shorter than the distance between the power supply point and the measurement unit. The reading device according to feature 6.

9. The device emits electromagnetic waves into the reading range and uses the energy of the electromagnetic waves to read the information returned from the RFID (Radio Frequency Identification) tag. The reading device according to any one of claims 1 to 8.

Images