JP2009273011A - Portable rfid reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control gain and directivity without increasing costs, upsizing a casing and decreasing reliability. <P>SOLUTION: A portable RFID reader/writer 1 is composed so that a parasitic element 31 can be attached or detached at a position for forming a director of Yagi antenna to an element 21 of a dipole antenna 20 and at a position for forming a reflector of Yagi antenna to the element 21 of the dipole antenna 20 while a parasitic element 30 can be attached or detached. By fitting the parasitic elements 30, 31, the Yagi antenna can be formed with the element 21 of the dipole antenna 20 and the parasitic elements 30, 31, thus appropriately controlling gain and directivity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable RFID reader / writer in which a housing is provided with a dipole antenna that transmits and receives radio waves to and from an RF tag.

In portable RFID reader / writers, for the purpose of controlling gain and directivity, a configuration is provided in which an antenna can be attached and detached and the angle and length of the antenna can be changed according to the application (for example, patents). References 1 and 2).
Japanese Patent No. 3637821 JP 2005-78100 A

  However, in a configuration in which another antenna is attached to the built-in antenna, it is necessary to provide a contact for supplying power to the other installed antenna and a circuit for separating the built-in antenna. It is also necessary to provide a mechanism for performing drip-proofing. As a result, there arises a problem that the cost is increased and the case size is increased, and there is a problem that reliability is deteriorated due to a contact failure of a contact for supplying power. Further, in the configuration in which the antenna is movable, it is necessary to provide a mechanism for moving the antenna. In this case as well, there arises a problem that the cost is increased and the housing size is increased.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to appropriately control gain and directivity without causing an increase in cost, an increase in size of a housing, or a decrease in reliability. It is an object of the present invention to provide a portable RFID reader / writer that can perform the above.

  According to the first aspect of the present invention, the position where the director of the Yagi antenna is formed with respect to the element of the dipole antenna that transmits and receives radio waves to and from the RF tag, and the element of the dipole antenna Since the attachment / detachment mechanism that can attach / detach the parasitic element is provided at least at one of the positions where the reflector of the Yagi antenna is formed, the element of the dipole antenna is not attached by attaching (attaching) the parasitic element to the housing. The Yagi antenna can be formed by the feed element, and the gain and directivity can be controlled appropriately.

  That is, the dipole antenna is linearly polarized and has an absolute gain of about 2.15 [dBi] at the maximum. In free space, the gain has a characteristic of drawing a figure 8 over the entire circumference in the direction perpendicular to the axis of the element. It is difficult to give a strong directivity in a desired direction (RF tag reading / writing direction) in which radio waves are to be transmitted and received. On the other hand, by attaching a parasitic element to the position of the dipole antenna element at the position where the director of the Yagi antenna is formed, the radio wave is strengthened, and the dipole antenna element By attaching a parasitic element to the position where the reflector is formed, the radio waves are weakened so that the radio wave is greatly radiated in the direction from the element of the dipole antenna toward the parasitic element side forming the director, The gain in the planar direction formed by including the element of the dipole antenna and the parasitic element can be increased, and strong (sharp) directivity can be given in that direction.

  Therefore, by attaching a parasitic element to the housing so that a plane is formed including the elements of the dipole antenna and the parasitic element in the desired direction in which the radio wave is to be transmitted / received, the desired direction in which the radio wave is to be transmitted / received Gain can be increased, and a strong directivity can be provided in a desired direction in which radio waves are to be transmitted and received. In this case, as described above, in order to increase the gain in the desired direction in which radio waves are to be transmitted and received, it is only necessary to attach a parasitic element to the housing, so a contact for supplying power to another antenna or a built-in antenna There is no need to provide a circuit for separating and a mechanism for preventing dust and drip, and it is possible to avoid an increase in cost, an increase in the size of the housing, and a decrease in reliability.

  According to the second aspect of the present invention, the element holding member having the attaching / detaching portion that is attachable / detachable with respect to the attaching / detaching mechanism of the casing is provided in a mode of holding the parasitic element, and the attaching / detaching portion of the element holding member is By attaching to the attachment / detachment mechanism, no power is supplied to at least one of the position where the director of the Yagi antenna is formed with respect to the element of the dipole antenna and the position of the reflector of the Yagi antenna with respect to the element of the dipole antenna. Since the element is arranged, the optimum directivity can be realized according to the usage form by performing a simple operation of attaching / detaching the element holding member to / from the housing.

  In other words, the element is used only when it is necessary to use a dipole antenna alone without attaching an element holding member to the housing in a normal use form and to have a strong directivity in a desired direction as a radio wave transmission / reception direction. By attaching the holding member to the housing and using the dipole antenna as a Yagi antenna together with the parasitic element, the characteristics of the antenna can be freely selected according to the usage form.

  According to the third aspect of the present invention, the element holding member is configured to be mounted on the attachment / detachment mechanism of the casing so that the element holding member can be rotated about the axis of the element of the dipole antenna. Even when the directivity is changed, it is not necessary to remove (remove) the element holding member mounted on the housing from the housing, and the element holding member can be mounted in the desired state while the element holding member is mounted on the housing. Directivity can be easily changed by rotating to a rotational position.

  According to the invention described in claim 4, a plane formed by including a dipole antenna element and a parasitic element arranged at a position where a director of the Yagi antenna is formed with respect to the element of the dipole antenna, or An element holding member is attached so that the electronic component does not relate to the plane formed including the element of the dipole antenna and the parasitic element arranged at the position where the reflector of the Yagi antenna is formed with respect to the element of the dipole antenna. Since the attachment / detachment portion of the element holding member is attached to the attachment / detachment mechanism of the housing so as to be rotatable about the axis of the element of the dipole antenna, it is formed including the element of the dipole antenna and the parasitic element. It is possible to prevent the gain and directivity from deteriorating due to the presence of electronic components on the flat surface. You can, gain and directivity can be controlled appropriately.

  According to the fifth aspect of the present invention, the optical code reading means for optically reading data from the data reading target is provided, the direction in which the dipole antenna transmits and receives radio waves to and from the RF tag, and the optical code reading means reads the data. The detachable part of the element holding member can be rotated on the axis of the element of the dipole antenna so that the element holding member can be rotated about the axis of the element of the dipole antenna so as to include the rotation position where the direction of optically reading data from the target is the same Since it is configured to be attached to the attachment / detachment mechanism, the direction in which the dipole antenna transmits and receives radio waves and the direction in which the optical code reading means optically reads data can be matched, and the data reading target having the RF tag and the information code The position of the portable RFID reader / writer with respect to the data reading target is not changed. , The data can be read data optically and from the information code can be read and written to the RF tag.

(First embodiment)
A first embodiment in which the present invention is applied to a portable RFID reader / writer having an information code reading function for optically reading data recorded in an information code (one-dimensional code or two-dimensional code) will be described below with reference to FIG. It will be described with reference to FIG. FIG. 1 shows the overall configuration of a portable RFID reader / writer. The portable RFID reader / writer 1 includes a case 2 made of, for example, a plastic material, which is formed into a bent shape having a generally “H” shape, a head 4 having a reading port 3, and a grip portion 5 that a user grips. Are combined.

  Housed in the housing 2 are a main circuit board 6, a radio circuit board 7, an optical code reading sensor 8 (optical code reading means in the present invention), a battery 9, and the like. The main circuit board 6 is a double-sided mounting board on which various parts can be mounted on both surface parts 6a and 6b, and a liquid crystal display 10 and a key switch part 11 are mounted on one surface part 6a. Various electronic components 12 are mounted on the other surface portion 6b.

  The wireless circuit board 7 is arranged in parallel with the main circuit board 6 described above, and is a double-sided mounting board on which various parts can be mounted on both surface portions 7a and 7b. The electronic component 13 is mounted, and various electronic components 14 are also mounted on the other surface portion 7b. The optical code reading sensor 8 has a function of optically reading data recorded in the information code, and is arranged so that the reading surface 8 a is flush with the opening surface 3 a of the reading port 3.

  In the housing 2, an opening 15 is formed in a rectangular shape on the upper surface 4 a of the head 4, and the transparent panel 16 is opposed to the display surface of the liquid crystal display 10 in the opening 15. Has been placed. An LED display unit 17 is disposed on the upper surface 4 a of the head 4 in the housing 2, and is integrated with the key switch unit 11 on the upper surface 5 a of the grip 5 in the housing 2. Several key tops 18 are arranged. When the user presses the key top portion 18, the pressing force is transmitted to the key switch portion 11, and the key switch portion 11 detects the key pressing operation by the user.

  Push-type trigger switches 19a and 19b for driving the optical code reading sensor 8 described above are arranged on the left and right side surfaces 5b and 5c of the holding unit 5 in the housing 2. In this case, when the user optically reads the data recorded in the information code, the user reads the data on the opening surface 3a of the reading port 3 (the reading surface 8a of the optical code reading sensor 8) while holding the grip portion 5. By pressing the trigger switches 19a and 19b while being addressed to the target information code, the optical code reading sensor 8 can be driven to optically read the data recorded in the information code. It is.

  In the housing 2, a dipole antenna 20 is extended on the head 4 in a direction orthogonal to the longitudinal direction of the housing 2 (directions indicated by “arrows S 1 and S 2” in FIG. 1). The element 21 of the dipole antenna 20 is made of, for example, a copper wire member having a circular longitudinal section, and its length (element length) is a length corresponding to a half wavelength (half wavelength) of radio waves. That is, for example, in a configuration for transmitting and receiving 950 [MHz] UHF band radio waves, one wavelength of the 950 [MHz] UHF band radio waves is about 32 [cm]. [Cm]. The power supply line 22 drawn out from the wireless circuit board 7 is connected to the intermediate portion of the element 21, and the intermediate portion of the element 21 to which the power supply line 22 is connected is a power supply point 23.

  FIG. 2 is a functional block diagram showing the electrical configuration of the portable RFID reader / writer 1 described above. The portable RFID reader / writer 1 has a microcomputer and executes a control program to control the overall operation of the portable RFID reader / writer 1, an RF tag processing unit 25 that transmits and receives radio waves, and the above-described components. An optical code reading sensor 8, an LED display unit 17, a liquid crystal display 10, an external interface (IF) unit 26, a key switch unit 11, a speaker 27, a memory 28, and a power supply unit 28 are provided. Has been.

  The RF tag processing unit 25 transmits a carrier wave modulated by transmission data from the dipole antenna 20, a receiving unit 25b that demodulates the carrier wave received by the dipole antenna 20 and extracts reception data, A signal processing unit 25c that performs signal processing on the transmission data and the reception data is provided. The external interface unit 26 has a wired or wireless connection interface with an external device provided outside the portable RFID reader / writer 1, and transmits / receives various data to / from the external device.

  The speaker 27 receives an output command from the control unit 24 when the control unit 24 normally completes the data transmission / reception operation in the RF tag processing unit 25 and the optical read operation of data in the optical code reading sensor 8, for example. And a notification sound for notifying the user that these operations have been completed normally. The memory 28 stores a control program executed by the control unit 24 and has a storage area capable of storing various work data. The power supply unit 29 generates operating power from the power supplied from the battery 9 and supplies it to each functional block. These functional blocks are constituted by the various electronic components 12 to 14 described above.

  In the present embodiment, the parasitic element 30 is detachably disposed at a position where the waveguide of the Yagi antenna is formed with respect to the element 21 of the dipole antenna 20 described above, and the Yagi is separated from the element 21 of the dipole antenna 20. The parasitic element 31 is detachably disposed at a position where the reflector of the antenna is formed.

  In this case, the parasitic element 30 that can be attached to and detached from the position where the element 21 of the dipole antenna 20 and the director of the Yagi antenna are formed, and the parasitic element 31 that can be attached to and detached from the position where the reflector of the Yagi antenna is formed. An example of the relationship is shown in FIG. The element length of the parasitic element 30 (indicated by “L1” in FIG. 3) is formed to be shorter than the length of the element 21 of the dipole antenna 20 (indicated by “L2” in FIG. 3). The length of the element 31 (indicated by “L3” in FIG. 3) is formed to be longer than the length of the element 21 of the dipole antenna 20. Further, the element of the parasitic element 30 and the element 21 of the dipole antenna 20 are parallel, and their distance (indicated by “D1” in FIG. 3) is about 0.5 to 1. The length corresponds to 4 times. The element of the parasitic element 31 and the element 21 of the dipole antenna 20 are parallel to each other, and their distance (indicated by “D2” in FIG. 3) is a length corresponding to a quarter wavelength of the radio wave. The relationship between the length of the element of the parasitic element 31 and the distance between the element of the parasitic element 31 and the element 21 of the dipole antenna 20 needs to be adjusted because the optimum value varies depending on the antenna configuration. .

  4 and 5 show a specific configuration in which the parasitic elements 30 and 31 described above are detachably attached to the portable RFID reader / writer 1. As shown in FIG. 4, the element holding member 32 is formed symmetrically in a “B” shape using, for example, resin or rubber having non-conductive characteristics, and corresponds to the parasitic element 30 described above. The first element 33 is fixed to the side portion 34, and the second element 35 corresponding to the parasitic element 31 is fixed to the side portion 36 facing the side portion 34. A rotating shaft 38 (detachable part in the present invention) is provided in the middle of the side part 37 that connects the side part 34 and the side part 36 on one side, and protrudes inward. A rotating shaft 40 (an attaching / detaching portion in the present invention) projects inward from an intermediate portion of the side portion 39 that connects the side portion 34 and the side portion 36 on the other side. Unlike the side part 34 and the side part 35, the side part 37 and the side part 39 can be elastically deformed outwardly because the first element 33 and the second element 35 are not fixed (see FIG. 4 is indicated by a two-dot chain line).

  The first element 33 and the line segment connecting the rotary shafts 38 and 40 are parallel to each other, and their distance (indicated by “D11” in FIG. 4) is the element of the parasitic element 30 described with reference to FIG. Is equal to the distance between the dipole antenna 20 and the element 21. The line segment connecting the second element 35 and the rotation shafts 38 and 40 is parallel, and the distance (indicated by “D12” in FIG. 4) is the element of the parasitic element 31 described in FIG. Is equal to the distance between the dipole antenna 20 and the element 21.

  On the other hand, as shown in FIG. 5, the housing 2 is provided with detachable mechanisms 42 a and 42 b symmetrically on the left and right side surfaces 4 b and 4 c of the head 4. Shaft holes 43 a and 43 b are formed in the attachment / detachment mechanisms 42 a and 42 b so as to be located on the axis of the element 21 of the dipole antenna 20. The inner diameters of the shaft hole portions 43a and 43b are slightly larger than the outer diameters of the rotary shafts 38 and 40 of the element holding member 32 described above. The user positions (opposes) the rotary shafts 38 and 40 in the shaft hole portions 43a and 43b in a state where the side portions 37 and 39 of the element holding member 32 are elastically deformed outward, and the side portion 37 of the element holding member 32 is placed. , 39 is released, the rotary shafts 38, 40 can be inserted into the shaft hole portions 43a, 43b, and the element holding member 32 can be attached to the housing 2.

  In this case, the first element 33 fixed to the side 34 of the element holding member 32 acts as a parasitic element 30 that forms a director of the Yagi antenna with respect to the element 21 of the dipole antenna 20, thereby holding the element. The second element 35 fixed to the side portion 36 of the member 32 acts as a parasitic element 31 that forms a reflector of the Yagi antenna with respect to the element 21 of the dipole antenna 20.

  Further, as described above, since the inner diameters of the shaft hole portions 43a and 43b are slightly larger than the outer diameters of the rotary shafts 38 and 40, the element holding member 32 is a dipole antenna as shown in FIG. It can rotate in the circumferential direction (indicated by “arrows P1 and P2” in FIG. 6) about the axis of the 20 elements 21 as the center of rotation. That is, the first element 33 rotates in a state where the distance from the element 21 of the dipole antenna 20 is maintained at a length corresponding to about 0.5 to 1.4 times the quarter wavelength of the radio wave. The element 35 rotates in a state where the distance from the element 21 of the dipole antenna 20 is maintained at a length corresponding to a quarter wavelength of the radio wave.

  In this case, the element holding member 32 includes a planar direction formed by including the element of the dipole antenna 20, the first element 33, and the second element 35, and a direction in which the optical code reading sensor 8 optically reads data. Can be rotated including a rotational position (the rotational position indicated by a solid line in FIG. 6) where the two are the same. For rotation prevention when the element holding member 32 rotates, the rotary shafts 38 and 40 and the shaft hole are formed by forming the rotary shafts 38 and 40 into a chamfered shape or using the spring effect of the element holding member 32. The contact surfaces with the portions 43a and 43b are brought into strong contact with each other, and the rotation stop is realized by the frictional force.

  Next, referring to FIG. 7, the simulation results of the antenna directivity when the element holding member 32 is not attached to the housing 2 and when the element holding member 32 is attached to the housing 2 will be described. explain.

  When the element holding member 32 is not attached to the housing 2, as shown in FIG. 7 (a), the dipole antenna 20 is linearly polarized and the absolute gain is about 2.15 [dBi] at maximum. In the space, the gain has a characteristic of drawing a figure 8 over the entire circumference in the direction perpendicular to the axis of the element 21. On the other hand, when the element holding member 32 is attached to the housing 2, the absolute gain of the antenna is about 9 [dBi] as shown in FIG. The arrangement of the first element 33 at the position acts to strengthen the radio waves, while the arrangement of the second element 35 at the position where the reflector is formed acts to weaken the radio waves. Thus, radio waves can be greatly radiated in the direction from the element 21 of the dipole antenna 20 toward the first element 33 side. As a result, in the plane direction formed including the element 21 of the dipole antenna 20, the first element 33, and the second element 35 (in FIG. 7, the plane direction formed including the x axis and the y axis). The gain can be increased and a strong (sharp) directivity can be provided in that direction.

  In the above-described embodiment, the configuration in which one element is provided as a director and one element is provided as a reflector has been described. However, a configuration in which a plurality of elements are provided as a director (multi-stage) Configuration). That is, as shown in FIG. 8, in the element holding member 51, for example, three elements 52 to 54 are provided as a director (in three stages), and one element 55 is provided as a reflector. May be. In this case, the three elements 52 to 54 acting as the director are formed to have a shorter length as they move away from the rotation shafts 56 and 57.

  As described above, according to the first embodiment, by attaching (attaching) the element holding member 32 to the housing 2 in the portable RFID reader / writer 1, the first element 33 is connected to the dipole antenna 20. The second element 35 is arranged at a position where a Yagi antenna reflector is formed with respect to the element 21 of the dipole antenna 20. Therefore, the arrangement of the first element 33 acts to strengthen the radio waves, and the arrangement of the second element 35 acts to weaken the radio waves. A large radio wave is radiated in a direction from the element 21 toward the first element 33 acting as a director, The antenna element 21 of 20 and can be as high as the first element 33 the gain of the second element 35 and a comprise planar direction is formed, can have a strong directivity in that direction.

  Therefore, by mounting the element holding member 32 so that a plane including the element of the dipole antenna 20, the first element 33, and the second element 35 is formed in a desired direction in which radio waves are to be transmitted and received, The gain in the desired direction in which the user wants to transmit / receive can be increased, and strong directivity can be given to the desired direction in which the radio wave is transmitted / received. In this case, in order to increase the gain in a desired direction in which radio waves are to be transmitted / received, the element holding member 32 may be attached to the housing 2, so that a contact for supplying power to another antenna or a built-in antenna is cut off. It is not necessary to provide a circuit for separating and a mechanism for performing dustproofing and dripproofing, and it is possible to avoid an increase in cost, an increase in the size of the housing, and a decrease in reliability.

  In addition, since the element holding member 32 is configured to be detachable from the housing 2, the dipole antenna 20 is used independently without attaching the element holding member 32 to the housing 2 in a normal usage mode, and radio waves are transmitted and received. The element holding member 32 is attached to the housing 2 and the dipole antenna 32 together with the first element 33 and the second element 35 is attached to the Yagi antenna only when it is necessary to give strong directivity to the desired direction. As a result, the characteristics of the antenna can be freely selected according to the usage pattern.

  In addition, since the element holding member 32 is configured to be rotatable about the axis of the element 21 of the dipole antenna 20, the element holding member 32 attached to the housing 2 can be used even when the directivity is changed. The directivity can be easily changed by rotating the element holding member 32 to a desired rotational position while keeping the element holding member 32 mounted on the housing 2 without having to be detached from (removed from) 2. .

  Furthermore, the dipole antenna 20 is rotated by rotating the element holding member 32 to a rotational position where the direction in which the dipole antenna 20 transmits and receives radio waves and the direction in which the optical code reading sensor 8 optically reads data from the data reading target are the same. The direction of transmitting and receiving radio waves and the direction of optical data reading by the optical code reading sensor 8 can be matched, and a portable RFID reader for the data reading target with respect to the data reading target having the RF tag and the information code. Without changing the position of the writer 1, data can be read from and written to the RF tag, and data can be optically read from the information code.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted about the same part as above-mentioned 1st Embodiment, and a different part is demonstrated. This 2nd Embodiment differs in the position of attachment / detachment mechanism 42a, 42c which attaches / detaches the element holding member 32 with respect to above-described 1st Embodiment.

  That is, in the portable RFID reader / writer 61, the attachment / detachment mechanism support portion 64 is formed integrally with the housing 62 so as to protrude from the upper surface portion 63a of the head portion 63 in the housing 62. The attachment / detachment mechanisms 42a and 42c described in the first embodiment are arranged on the attachment / detachment mechanism support portion 64.

  In the first embodiment described above, since the rotation center axis of the element holding member 32 is disposed inside the housing 2, the element 21, the first element 33, and the second element 35 of the dipole antenna 20 are connected to each other. The element holding member 32 cannot rotate to a position where the plane formed including the plane is parallel to the longitudinal direction of the housing 2. On the other hand, in the second embodiment, the center axis of rotation of the element holding member 32 is disposed outside the housing 62 and above the upper surface portion 63a of the head 63, and therefore the element 21 of the dipole antenna 20 is used. The plane formed including the first element 33 and the second element 35 is parallel to the longitudinal direction of the housing 62 (the direction indicated by “arrows S1 and S2” in FIG. 9) (in FIG. 9). Then, the element holding member 32 can rotate up to a position indicated by a two-dot chain line.

  Therefore, according to the second embodiment, the gain can be increased in the direction parallel to the longitudinal direction of the housing 62 as a direction in which radio waves are transmitted and received, and strong directivity can be given in that direction.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted about the same part as above-mentioned 1st Embodiment, and a different part is demonstrated. In the third embodiment, the positions of the attaching / detaching mechanisms 42a and 42c for attaching / detaching the element holding member 32 are different from those in the first embodiment.

  That is, in the portable RFID reader / writer 71, the front protrusion 73 is formed integrally with the housing 72 on the front surface 73 a of the head 73 and protrudes forward from the front surface 73 a in the housing 72. The attachment / detachment mechanism support portion 64 that protrudes from the upper surface portion 74a and is described in the above-described second embodiment is formed integrally with the front protrusion portion 74 on the upper surface portion 74a of the front protrusion portion 74. Detachable mechanisms 42a and 42c are arranged on the mechanism support 64.

  In the third embodiment, the center axis of rotation of the element holding member 32 is disposed outside the housing 72 and in front of the front surface portion 73a of the head 73 and above the upper surface portion 73b. The plane formed including the first element 33, the first element 33, and the second element 35 is parallel to the longitudinal direction of the housing 72 (the direction indicated by “arrows S1 and S2” in FIG. 9) ( The element holding member 32 is rotatable up to the position indicated by one of the two-dot chain lines in FIG. 10 and is perpendicular to the longitudinal direction of the housing 72 (the position indicated by the other two-dot chain line in FIG. 10). Up to this, the element holding member 32 can rotate.

  Therefore, according to the third embodiment, the gain can be increased in a direction parallel to the longitudinal direction of the casing 72 as a direction in which radio waves are transmitted and received, and the gain is also perpendicular to the longitudinal direction of the casing 72. It can be made high and strong directivity can be given to those directions. In this case, since the optical code reading sensor 8 does not lie on the plane formed by including the element 21 and the first element 33 of the dipole antenna 20, the gain and directivity are affected by the influence of the optical code reading sensor 8. It is possible to avoid a decrease in performance, and it is possible to appropriately control the gain and directivity.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The present invention can also be applied to a configuration that does not have an optical code reading sensor.
The tip side of the element of the dipole antenna may be formed into a bent shape, or the element of the dipole antenna may be formed into a folded shape.

The 1st Embodiment of this invention is shown, the top view which shows the whole structure, a front view, and a vertical side view Functional block diagram The figure which shows an example of the relationship between the element of a dipole antenna and a parasitic element A plan view and a side view showing the element holding member The top view and side view which show the aspect by which the element holding member is mounted | worn Side view showing an aspect in which the element holding member is rotatable Diagram showing simulation results 4 equivalent diagram The side view which shows the 2nd Embodiment of this invention and shows the aspect which an element holding member can rotate The side view which shows the 3rd Embodiment of this invention and shows the aspect which an element holding member can rotate

Explanation of symbols

  In the drawings, 1 is a portable RFID reader / writer, 2 is a housing, 8 is an optical code reading sensor (optical code reading means), 20 is a dipole antenna, 21 is an element, 30 and 31 are parasitic elements, and 32 is an element holding element. Members, 38 and 40 are rotary shafts (detachable portions), 42a and 42c are removable mechanisms, 51 is an element holding member, 56 and 57 are rotary shafts (detachable portions), 61 is a portable RFID reader / writer, 62 is a housing, Reference numeral 71 denotes a portable RFID reader / writer, and 72 denotes a housing.

Claims (5)

A portable RFID reader / writer in which a housing is provided with a dipole antenna that transmits and receives radio waves to and from an RF tag,
The parasitic element is at least one of a position where a director of the Yagi antenna is formed with respect to the element of the dipole antenna and a position of the reflector of the Yagi antenna with respect to the element of the dipole antenna. A portable RFID reader / writer characterized in that an attachment / detachment mechanism that can attach / detach is provided. The portable RFID reader / writer according to claim 1,
The parasitic element is provided in an aspect that is held by an element holding member having a detachable part that can be attached to and detached from the attachment / detachment mechanism of the housing,
The attachment / detachment portion of the element holding member is attached to the attachment / detachment mechanism of the housing, so that the position of the director of the Yagi antenna is formed with respect to the element of the dipole antenna and the Yagi antenna with respect to the element of the dipole antenna The portable RFID reader / writer is characterized in that the parasitic element is disposed at at least one of the positions where the reflector is formed. The portable RFID reader / writer according to claim 2,
A portable RFID reader / writer, wherein an attaching / detaching portion of the element holding member is attached to an attaching / detaching mechanism of the housing so that the element holding member can rotate about the axis of the element of the dipole antenna. The portable RFID reader / writer according to claim 3,
A plane formed including the element of the dipole antenna and a parasitic element arranged at a position where a waveguide of the Yagi antenna is formed with respect to the element of the dipole antenna, or the element of the dipole antenna and the dipole antenna The element holding member is positioned on the axis of the element of the dipole antenna so that the electronic component does not relate to a plane formed including a parasitic element arranged at a position where the reflector of the Yagi antenna is formed with respect to the element. A portable RFID reader / writer in which an attaching / detaching portion of the element holding member is attached to the attaching / detaching mechanism of the housing so as to be rotatable around the center of rotation. The portable RFID reader / writer according to claim 3 or 4,
Optical code reading means for optically reading data from a data reading target is provided,
The element holding member includes a rotational position in which a direction in which the dipole antenna transmits and receives radio waves to and from the RF tag and a direction in which the optical code reading unit optically reads data from a data reading target are included. A portable RFID reader / writer characterized in that an attachment / detachment portion of the element holding member is attached to an attachment / detachment mechanism of the casing so as to be rotatable about the axis of the element of the dipole antenna.

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