JP2021073558A - Wireless tag and system - Google Patents

Abstract

To achieve a wireless tag and a system allowing easy confirmation of a communication state between the wireless tag and a master machine.SOLUTION: A wireless tag 10 includes: electric field intensity detection means 103 for detecting intensity of an electric wave from a master machine 20; a light emission unit 12 having a light emission element 121; and a light emission element control unit 104 for controlling both or one of a luminous color and blinking of the light emission element 121, according to the intensity of the electric wave from the master machine 20 detected by the electric field intensity detection means 103, so that the electric field intensity can be confirmed to determine the quality of a communication state by visual inspection or the like of the luminous color or the like of the light emission unit 12 from a place separated from the wireless tag 10, and the communication state can be adjusted easily to a preferable one by adjusting a position/direction of the wireless tag while visually observing the luminous color or the like of the light emission unit 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless tag and a system provided with a display for displaying the strength of radio waves from a master unit.

In order to detect the storage location, type, quantity, etc. of articles exhibited and stored in warehouses and stores, an article management system that detects the position of the wireless tag by attaching a wireless tag to the article is practical. (For example, RFID (Radi Frequency Identification) system). In such an article management system, a master unit communicates with a wireless tag which is a slave unit through a wireless line under the control of a computer or the like, and the computer or the like identifies each wireless tag by their unique identification code and wirelessly. By detecting the position of the tag, the storage location, type, quantity, etc. (article information) of each article are detected.

Therefore, in such an article management system, the communication state of the wireless line between the master unit and the wireless tag must be maintained in good condition. However, wireless lines in stores and warehouses where an article management system is installed have the strength of radio waves (electric field strength) from the master unit due to the reflection and absorption of radio waves by the installations on the walls, ceiling, floor and buildings. ) May become weak and it may not be possible to maintain a good communication state.

Further, in a specific place such as in a store, a so-called null point may occur in which the electric field strength is remarkably lowered due to multipath propagation in which a plurality of radio wave propagation paths are formed between the master unit and the wireless tag. ..

The wireless tag placed at such a null point causes a failure in communication with the master unit, and the article management system cannot detect the article information. Null points generally become narrower as the frequency of radio waves increases, and the number of null points also increases, making them more susceptible to the surrounding environment (distance to walls, other articles placed adjacent to them, etc.). For example, in the 2.4 GHz band, since the wavelength is as short as about 13 cm, a null point may occur even if the attachment position of the wireless tag is changed by about several centimeters or the attachment direction of the wireless tag is slightly changed.

As a technique for detecting such a place where the electric field strength is weak or a null point, a radio wave measuring instrument for measuring the electric field strength in the frequency band used for the article management system has been developed. For example, the radio wave measuring instrument disclosed in Patent Document 1 displays the electric field strength detected by the antenna with a level meter composed of a plurality of light emitting diodes. This radio wave measuring instrument can display that the electric field strength is equal to or higher than a predetermined value, and can also detect the direction of arrival of the radio wave.

Japanese Unexamined Patent Publication No. 2016-40523

However, even if the wireless tag is attached to the article after confirming that the electric field strength is sufficient using a radio wave measuring instrument, if the quantity or position of the article placed around it changes, or the installation location of the master unit is changed. If it is changed, the strength of the radio wave from the master unit may decrease and fall below the detection limit of the wireless tag, or a null point may occur at the position of the antenna of the wireless tag due to multipath propagation.

Then, every time the surrounding environment changes, or when it may change, maintenance personnel, etc., in order to maintain the communication state, the place where the goods etc. with the wireless tag are placed (multiple places such as warehouse). The strength of the radio wave from the master unit must be measured by patrol. Confirmation of the communication status by such a radio wave measuring instrument is complicated and leads to an increase in the running cost of the article management system.

Even if a location with low electric field strength or a null point is found using a radio wave measuring instrument, the wireless tag should be positioned appropriately while avoiding the null point due to the difference in the positional relationship between the antenna of the wireless tag and the antenna of the radio wave measuring instrument. Can be difficult.

Therefore, according to the present invention, it is possible to easily confirm whether or not the communication state between the wireless tag attached to the article or the like and the master unit is good from a place away from the wireless tag, and the maintenance personnel and the like can easily check the communication state. When it was discovered that it was not good, the challenge was to realize a wireless tag that can easily adjust the attachment position and attachment direction of the wireless tag that provides good communication conditions.

In order to solve the above problems, the wireless tag according to the present invention includes an electric field strength detecting means for detecting the strength of a radio wave from a received master unit, a light emitting unit, a light emitting element included in the light emitting unit, and an electric field strength detection. A configuration including a light emitting element control unit for controlling both or one of the light emitting color and blinking of the light emitting element according to the intensity of the radio wave from the master unit detected by the means (claim 1).

In the wireless tag, the light emitting element control unit controls both or one of the light emitting color and blinking of the light emitting element according to the strength of the radio wave from the master unit. For example, when the electric field from the master unit can be received strongly or satisfactorily, the light emitting unit controlled by the light emitting element control unit emits green light, and the radio wave from the master unit is not strong, but the reception sensitivity of the wireless tag is lower than that of the radio tag. When not, the light emitting unit controlled by the light emitting element control unit emits yellow light, and when the radio wave from the master unit is weak and before or after the detection limit or below the detection limit, the light emitting unit controlled by the light emitting element control unit emits red light. ..

Further, as described in claim 2, the light emitting unit of the wireless tag is provided with a light diffusing unit that diffuses the light emitted by the light emitting element, so that the light from the light emitting element can be emitted to a wide range.

Further, as described in claim 3, if the light emitting element is a light emitting diode, high brightness light emission can be realized with low power consumption.

Further, as described in claim 4, the light from the light emitting portion is further widened by positioning the light emitting portion on at least one wall surface of the wireless tag and projecting the light diffusing portion from the wall surface on which the light emitting portion is positioned. Can spread over a range.

According to the wireless tag according to the present invention having the above configuration, the communication state between the wireless tag and the master unit is confirmed by confirming the light emitted by the wireless tag from a monitoring place or the like away from articles or the like. Can be done. For example, a wireless tag that emits light from a wireless tag and has strong radio waves from the master unit and can communicate normally with the master unit, and a wireless tag that does not have strong radio waves from the master unit but can communicate normally with the master unit. Alternatively, identify a wireless tag that cannot normally receive radio waves from the master unit (unfavorable communication status), go to the wireless tag with unfavorable communication status, and slightly shift or direct the position of the wireless tag. Good communication with the master unit can be ensured by changing the radio wave. That is, by using the wireless tag according to the present invention, it is possible to realize an article management system that can reliably detect article information such as the storage location and quantity of articles.

It is a figure which shows the schematic appearance structure of the wireless tag which concerns on this invention. It is a figure which shows the schematic circuit structure of the wireless tag shown in FIG. It is a figure which shows the schematic circuit structure of the light emitting part and the light emitting element control part of the wireless tag shown in FIG. It is a figure for demonstrating the communication state between a wireless tag and a master unit shown in FIG. 1, and FIG. 1A shows the case where there is no obstacle or the like between a wireless tag and a master unit, and FIG. (B) shows a case where an obstacle intervenes between the wireless tag and the master unit, and FIG. 3C shows a multipath radio wave propagation path formed between the wireless tag and the master unit by a reflection wall or the like. Show the case. It is a figure for demonstrating the diffusion of the light emitted from the light emitting part of the wireless tag shown in FIG.

Hereinafter, the wireless tag according to the present invention will be described with reference to the drawings.

<Outline configuration of wireless tag>
As shown in FIG. 1, the wireless tag 10, which is an embodiment of the wireless tag according to the present invention, has, for example, a tag main body 11 having a substantially rectangular shape and a flat plate shape, and a top plate surface of the tag main body 11 (of the wireless tag). A light emitting unit 12 positioned on the one wall surface) 11a is provided.

As shown in FIG. 2, the wireless tag 10 includes, for example, a battery (not shown) for driving the wireless tag 10 in addition to the antenna 101 and the transmission / reception unit 102 inside the tag main body 11. The transmission / reception unit 102 includes, in addition to a transmission / reception means (not shown) for communicating with the master unit and a computer (not shown) for controlling communication with the master unit, at least the strength of radio waves from the master unit. The electric field strength detecting means 103 and the light emitting element control unit 104 for measuring the above are provided.

Here, the electric field strength detecting means 103 identifies and detects the strength of the radio wave of the master unit captured by the antenna 101 into the following plurality of levels, for example.
Level 1: The strength of radio waves is strong enough.
Level 2: The strength of radio waves is strong.
Level 3: The strength of the radio wave is not strong but not weak.
Level 4: The strength of the radio wave is weak, but it is stronger than the detection limit of the wireless tag 10.
Level 5: The strength of the radio wave is close to the detection limit of the wireless tag 10 (barely detectable).
Level 6: The strength of the radio wave is below the detection limit of the wireless tag 10 (cannot be detected).

As shown in FIG. 3, the light emitting unit 12 includes a light emitting element 121 (s) and a light diffusing unit 122, and the light emitting element (light emitting diode) 121 includes, for example, a red light emitting diode chip 121r (s) and a red light emitting diode chip 121r (s). It is equipped with 121 g (s) of green light emitting diode chips.

The light diffusing portion 122 (see FIGS. 1 and 3) is formed of, for example, a milky white plastic plate material and has a substantially semi-cylindrical shape with an open bottom. In the internal space thereof, for example, the top plate surface of the tag body 11 is formed. The light emitting element 121 positioned so as to protrude from 11a is positioned.

As shown in FIG. 3, the red light emitting diode chip 121r is controlled to blink by the red switch circuit 104r of the light emitting element control unit 104, and the green light emitting diode chip 121g is controlled to blink by the green switch circuit 104g of the light emitting element control unit 104. ..

<Changes in communication status between the base unit and wireless tag>
Next, the relationship between the communication state between the wireless tag 10 and the master unit 20 and the light emission of the light emitting unit 12 will be described with reference to FIG.

Here, when the communication state between the master unit and the wireless tag is good, the wireless tag 10 emits, for example, green light Lg from the light emitting unit 12, paying attention to the communication state between the master unit and the wireless tag. When necessary, the wireless tag 10 emits, for example, red light Lr and green light Lg from the light emitting unit 12, and when the radio wave intensity of the master unit is before or after the detection limit of the wireless tag or below the detection limit, the radio tag 10 is wireless. The tag 10 emits, for example, red light Lr from the light emitting unit 12.

<When communication is good>
In FIG. 4A, it is assumed that the wireless tag 10 is stored or displayed together with the article 30 relatively close to the master unit 20. In such a case, the wireless tag 10 and the master unit 20 are often maintained in a good communication state via the radio wave propagation path P1 at the shortest distance and without any obstacles. In this case, the radio tag 10 and the master unit 20 are maintained in a good communication state. The electric field strength detecting means 103 included in the wireless tag 10 detects the strength of the radio wave from the master unit 20 as any of level 1 to level 3.

Based on the detection result of the electric field strength detecting means 103, the green switch circuit 104g of the light emitting element control unit 104 continuously or periodically conducts, and the green light emitting diode chip 121g of the light emitting element 121 is continuously lit. Or blink at regular intervals.

The green light Lg emitted in this way is diffused by the light diffusing portion 122 of the light emitting portion 12, and as shown in FIG. 5, the article 30 to which the wireless tag 10 is attached is substantially in all directions on the top plate surface 11a side of the tag main body 11. Is diffused in almost all directions that can be seen. As a result, the maintenance personnel of the article management system visually observes the green light Lg from the light emitting unit 12 from a place away from the article 30, and the communication state between the master unit 20 and the wireless tag 10 attached to the article 30 is good. You can confirm that there is.

<When you need to pay attention to the communication status>
In FIG. 4A, it is assumed that the wireless tag 10 is stored or exhibited together with the article 30 in a place close to the outside of the service area of the master unit 20 although it is inside the service area. In such a case, the communication state between the wireless tag 10 and the master unit 20 via the radio wave propagation path P1 often requires attention. In this case, the electric field strength detecting means 103 included in the wireless tag 10 is the parent. The intensity of the radio wave from the machine 20 is detected as level 4 or 5 (or level 4).

Based on the detection result of the electric field strength detecting means 103, the green switch circuit 104g and the red switch circuit 104r of the light emitting element control unit 104 conduct continuously or at regular intervals, and the green light emitting diode chip 121g and the red light emitting diode chip 121r Lights up continuously or blinks at regular intervals.

The red light Lr and the green light Lg emitted in this way are diffused by the light diffusing portion 122 of the light emitting portion 12, and are diffused in substantially all directions on the top plate surface 11a side of the tag main body 11 as shown in FIG. As a result, the maintenance personnel of the article management system recognizes the green light Lg and the red light Lr of the light emitting unit 12 as yellow light or orange light from a place away from the article 30, and wirelessly attached to the master unit 20 and the article 30. It can be confirmed that the communication state with the tag 10 is a state requiring attention.

As shown in FIG. 4B, when an obstacle S (for example, a wall, another article, a person, etc.) intervenes in the radio wave propagation path P2 between the wireless tag 10 and the master unit 20, the master unit 20 The radio wave from is attenuated, and the communication state may become a state requiring attention. Also at this time, the electric field strength detecting means 103 included in the wireless tag 10 detects the strength of the radio wave from the master unit 20 as level 4 or 5 (or level 4).

As shown in FIG. 4C, the radio wave propagation path P3 from the master unit 20 and the radio wave propagation path P4 reflected by the reflection wall R (for example, ceiling, wall, other articles, etc.) When reaching the antenna 101 of the wireless tag 10 via the multipath propagation path formed by, be careful of the communication state due to the interference of the multipath radio waves even if the distance between the wireless tag 10 and the master unit 20 is short. It may be in a state that requires. Also at this time, the electric field strength detecting means 103 included in the wireless tag 10 detects the strength of the radio wave from the master unit 20 as level 4 or 5 (or level 4).

The green switch circuit 104g and the red switch circuit 104r of the light emitting element control unit 104 are continuously or continuously based on the detection result of the electric field strength detecting means 103 even when the obstacle S is present and in the case of the above-mentioned multi-pass. Conducting with a constant cycle, the green light emitting diode chip 121g and the red light emitting diode chip 121r are continuously lit or blinked at a constant cycle.

As shown in FIG. 5, the red light Lr and the green light Lg emitted in this way are diffused in substantially all directions on the top plate surface 11a side of the tag body 11, and as a result, the maintenance personnel of the article management system are separated from the article 30. By recognizing the yellow light or the orange light from the location, it can be confirmed that the communication state between the master unit 20 and the wireless tag 10 attached to the article 30 requires attention.

By the way, even if the maintenance personnel of the article management system can confirm that the communication status requires attention, it depends on the distance between the wireless tag 10 and the master unit 20, the obstacle S, or the multipath. In many cases, it is difficult to distinguish.

Therefore, when the maintenance personnel of the article management system confirms that the communication state between the master unit 20 and the wireless tag 10 attached to the article 30 needs attention with the emission color of the light diffusing unit 122, the maintenance personnel go to the article 3 Therefore, the antenna 101 of the wireless tag 10 can satisfactorily receive the radio wave from the wireless tag 30 by shortening the distance between the wireless tag 10 and the master unit 20 or changing the direction of the wireless tag 10 with respect to the article 30. (It is desirable to improve the reception state of the wireless tag 10). The improvement of the reception state of the wireless tag 10 can be easily determined by whether or not the emission color of the light emitting element 121 changes to green.

<When the strength of the radio wave of the master unit is before or after the detection limit of the wireless tag, or below the detection limit>
In FIG. 4A, it is assumed that the wireless tag 10 is stored or exhibited together with the article 30 in the boundary region between the service area and the outside of the service area of the master unit 20 or outside the service area. In such a case, the strength of the radio wave of the master unit is often before or after the detection limit of the wireless tag or below the detection limit. In this case, the electric field strength detecting means 103 of the wireless tag 10 is the radio wave of the master unit. Intensity is detected as level 5 or 6 (or level 6).

Based on the detection result of the electric field strength detecting means 103, the red switch circuit 104r of the light emitting element control unit 104 conducts continuously or at a fixed cycle, and the red light emitting diode chip 121r is continuously lit or at a fixed cycle. Make it blink.

The red light Lr emitted in this way is diffused by the light diffusing unit 122 of the light emitting unit 12, and is diffused in substantially all directions on the top plate surface 11a side of the tag main body 11 as shown in FIG. Can confirm that there is a problem in the communication state between the master unit 20 and the wireless tag 10 attached to the article 30.

As shown in FIG. 4B, when the obstacle S intervenes in the radio wave propagation path P2 between the wireless tag 10 and the master unit 20, the radio wave from the master unit 20 is attenuated and the master unit 20 The strength of the radio wave may be before or after the detection limit of the wireless tag 10 or below the detection limit. Also at this time, the electric field strength detecting means 103 included in the wireless tag 10 detects the strength of the radio wave of the master unit as level 5 or 6 (or level 6).

As shown in FIG. 4C, the radio wave from the master unit 20 passes through the multipath propagation path formed by the radio wave propagation path P3 having the shortest distance and the radio wave propagation path P4 reflected by the reflection wall R. When reaching the antenna 101 of the wireless tag 10, even if the distance between the wireless tag 10 and the master unit 20 is short, the radio waves from the master unit 20 are attenuated due to the interference of the multipath radio waves, and the radio waves of the master unit 20 are radio waves. The strength of the radio wave tag 10 may be around the detection limit or below the detection limit. Also at this time, the electric field strength detecting means 103 included in the wireless tag 10 detects the strength of the radio wave from the master unit 20 as level 5 or 6 (or level 6).

Even when an obstacle S is present and in the case of the above-mentioned multipath, the red switch circuit 104r of the light emitting element control unit 104 is continuously or periodically conductive based on the detection result of the electric field strength detecting means 103. The red light emitting diode chip 121r is continuously lit or blinks at regular intervals.

As shown in FIG. 5, the red light Lr emitted in this way is diffused in substantially all directions on the top plate surface 11a side of the tag body 11, and as a result, the maintenance personnel of the article management system are red from a place away from the article 30. By visually observing the optical Lr, it can be confirmed that the radio wave from the master unit 20 is attenuated and the strength of the radio wave of the master unit 20 is before or after the detection limit of the wireless tag 10 or below the detection limit.

By the way, the maintenance personnel of the article management system is in a state where the radio wave from the master unit 20 is attenuated by the emission color of the light diffusing unit 122 and the intensity of the radio wave of the master unit 20 becomes around the detection limit of the wireless tag 10 or below the detection limit. Even if it can be confirmed, it is difficult to determine in many cases whether it is due to the distance between the wireless tag 10 and the master unit 20, due to the obstacle S, or due to multipath.

Therefore, when the maintenance personnel of the article management system confirms that the communication state between the master unit 20 and the wireless tag 10 attached to the article 30 needs attention with the emission color of the light diffusing unit 122, the maintenance personnel go to the article 3 Therefore, the antenna 101 of the wireless tag 10 can satisfactorily receive the radio wave from the wireless tag 30 by shortening the distance between the wireless tag 10 and the master unit 20 or changing the direction of the wireless tag 10 with respect to the article 30. (Improve the reception state of the wireless tag 10). The improvement of the reception state of the wireless tag 10 can be easily determined by whether or not the emission color of the light emitting element 121 changes to green.

By the way, it is preferable to reduce the power consumption of the light emitting element 121. Therefore, for example, the master unit 20 issues a command to each wireless tag 10 to check the communication status, and the wireless tag 10 that receives this command activates the light emitting element control unit 104 to activate the electric field strength detecting means 103. It is preferable to drive the light emitting element 121 to emit light based on the detection result. In this case, after confirming the communication state, the wireless tag 10 stops the operation of the light emitting element control unit 104 and the light emitting element by canceling the command to check the communication state issued by the master unit 20. Power consumption is reduced by stopping the light emitting drive of 121.

On the other hand, in the wireless tag 10 that cannot receive the command to check the communication status, the electric field strength detecting means 103 detects the strength of the radio wave of the master unit as level 6, so that the command to check the communication status is issued. Regardless of the presence or absence, the light emitting unit 12 emits red light Lr.

<Modification example>
The wireless tag according to the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented without changing the gist thereof.

For example, the communication status between the wireless tag and the master unit can be determined in three cases: when it is good, when caution is required, and when the strength of the radio wave of the master unit is before or after the detection limit of the wireless tag or below the detection limit. It is not limited, for example, when it is good, when caution is required, when the strength of the radio wave of the master unit is close to the detection limit of the wireless tag, or when the strength of the radio wave of the master unit is less than or equal to the detection limit of the wireless tag. It may be further subdivided. In this case, the emission color of the light emitting element is increased.

The shape of the light diffusing part is not limited to the shape of a semi-cylindrical part, and the light diffusing part is positioned on one wall surface of the tag body, and the light emitted by the light emitting element is transmitted to a wide range on the one wall surface side, preferably almost all. It may be a hemispherical shape formed of a plastic plate, for example, as long as it can diffuse in the direction.

Further, the light emitting portion may be provided not only on one wall surface (top plate surface) of the wireless tag but also on another wall surface (side wall surface) so as to emit light in a wider range.

Of course, various modes of light emission such as continuous light emission, blinking light emission, and light emission in which the blinking cycle changes can be considered.

Since the wireless tag according to the present invention can be industrially manufactured, used, etc., and can be sold, rented, etc., the present invention is an invention having industrial applicability.

10 Wireless tag (slave unit)
103 Electric field strength detecting means 104 Light emitting element control unit 11a One wall surface of the wireless tag (top plate surface of the wireless tag body)
12 Light emitting unit 121 Light emitting element 122 Light diffusing unit 20 Master unit

Claims (5)

A wireless tag that communicates with the base unit via a wireless line.
An electric field strength detecting means for detecting the strength of radio waves from the master unit,
A light emitting unit located on at least one wall surface of the wireless tag,
The light emitting element of the light emitting unit and
A light emitting element control unit that controls both or one of the light emitting color and blinking of the light emitting element according to the strength of the radio wave from the master unit detected by the electric field strength detecting means is provided.
The light emitting element control unit drives the light emitting element to emit light when it receives a command to check the communication state from the master unit, and when the master unit cancels the command, the light emitting element said. A wireless tag characterized by stopping the light emission drive. The light emitting unit
The wireless tag according to claim 1, further comprising a light diffusing unit that diffuses light emitted by the light emitting element. The wireless tag according to claim 1 or 2, wherein the light emitting element is a light emitting diode. The wireless tag according to claim 2 or 3, wherein the light emitting portion is positioned on at least one wall surface of the wireless tag, and the light diffusing portion projects from the wall surface on which the light emitting portion is positioned. It is a system equipped with a wireless tag that communicates with the master unit via a wireless line.
The wireless tag is
An electric field strength detecting means for detecting the strength of radio waves from the master unit,
A light emitting unit located on at least one wall surface of the wireless tag,
The light emitting element of the light emitting unit and
A light emitting element control unit that controls both or one of the light emitting color and blinking of the light emitting element according to the strength of the radio wave from the master unit detected by the electric field strength detecting means is provided.
The master unit is
A means for issuing a command to the wireless tag to check the communication status, and
A means for canceling the command after confirming the communication status is provided.
The wireless tag is
When the command is received, the light emitting element control unit is operated to drive the light emitting element to emit light based on the detection result of the electric field strength detecting means.
A wireless tag system including a means for operating the light emitting element control unit to stop the light emitting drive of the light emitting element when the master unit releases the command.

Images