JP2025148153A - Wearable Antenna Device - Google Patents

Abstract

To provide a wearable antenna device that can accurately and reliably detect the position of an object to be worn or detected.SOLUTION: A wearable antenna device 1 is constructed that is attachable to a wrist P, which is an object to be worn, and that performs presence detection using electromagnetic properties. The wearable antenna device 1 includes a device main body 2 that incorporates a circuit board 20, and an antenna body 3 that has one end electrically connected to the circuit board 20 as a fixed end and that can be wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction along the outer periphery of the wrist P, either together with the device main body 2 or alone.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wearable antenna device, and more particularly to improvements to its structure.

Japanese Patent Publication No. 3254880 describes a wrist-worn antenna device. The wrist-worn antenna device (1) comprises a device main body (1a) having an internal circuit board (5) and connected to wrist bands (2a, 2b), and an antenna (13) having a longitudinal groove (13c), fixed to the device main body (1a) and the wrist bands (2a, 2b), and positioned above the circuit board (5) inside the device main body (1a) (see claim 1, paragraph [0012], and Figures 1 to 3 of the publication).

The above publication states that because there is no circuit board (5) on the surface side of the antenna body (1a), the radio waves emitted from the antenna body (1a) are not blocked, and sensitivity can be improved (paragraphs [0011] and [0013] of the publication).

The wrist-worn antenna device described in the above publication is a slot antenna whose inductance value is determined by the perimeter of the groove (13c) in the antenna body (13) (see paragraph [0005] of the same publication). Slot antennas are generally directional antennas, and Figure 4(a) of the above publication shows the typical directivity when a slot antenna is used (see paragraph [0034] of the same publication).

In the device described in the above publication, radio waves are transmitted and received on the front side of the wrist-worn antenna device (1), i.e., on the side of the data display device (3) (see Figures 3 and 8), so that the radio wave radiation energy is directional toward the data display device (3) (see paragraph [0031] of the publication). As a result, the radiation pattern of the wrist-worn antenna device (1) exhibits high directivity toward the front side of the antenna body (1a) (see paragraph [0045] of the publication and the solid line 20 in Figure 8).

The wrist-worn antenna device described in the above publication is specialized for use as a wireless device (see paragraph [0001] of the publication).
On the other hand, in a work environment where humans and robots work together, there is a demand to detect the approach (or relative position) of a collaborative robot to a worker from the viewpoint of ensuring the safety of the worker.
However, because the conventional wrist-mounted antenna device has high directivity, it may not be able to detect the worker's arm depending on the direction of the worker's arm. In such cases, it is expected that the worker may be exposed to danger or may be injured. Therefore, the conventional wrist-mounted antenna device is not suitable for use in collaborative work with a collaborative robot.

The present invention was made in consideration of these conventional circumstances, and the problem that the present invention aims to solve is to provide a wearable antenna device that can accurately and reliably detect the position of the object to which it is attached or the object to be detected. The present invention also aims to provide a wearable antenna device that is suitable for a working environment involving a collaborative robot.

To solve the above problems, the present invention provides a wearable antenna device that can be attached to an object and that uses electromagnetic properties to detect the presence of the object. The device includes a device main body that incorporates a circuit board, and an antenna body that is at least partially electrically connected to the circuit board as a fixed end and that can be wrapped around the entire circumference of the object without gaps, either together with the device main body or alone.

In the present invention, the fixed end of the antenna is electrically connected to the circuit board of the device body, and the antenna is wrapped around the entire circumference of the object to be attached, either together with the device body or alone, without leaving any gaps in the circumferential direction.

According to the present invention, the antenna can be wrapped around the entire circumference of the object without leaving any gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave strength in all directions (360 degrees) around the antenna. This prevents radio wave strength from varying depending on the orientation of the device body or the object, making it possible to accurately and reliably detect the position of the object or the object being detected.

In this invention, a part of the antenna is one end of the antenna, which is a fixed end electrically connected to the circuit board, and the other end of the antenna is a free end, and when the antenna is wrapped around the outer periphery of the object to be attached, the other end of the antenna passes through the back side of the device body and can be engaged with the device body.

The present invention further includes a belt that is disposed on the inner periphery of the antenna, is detachably attached to the device body via a locking portion, and can be wrapped around the entire circumference of the object without gaps in the circumferential direction along the outer periphery of the object, and the antenna, disposed on the outer periphery of the belt, can be detachably attached to the locking portion.

In the present invention, the antenna body has a first metal layer arranged on the inner periphery and a second metal layer arranged on the outer periphery, with the first metal layer forming either the ground or the antenna element, and the second metal layer forming the other of the ground or the antenna element.

In this invention, the antenna body is composed of a first metal layer arranged on the inner periphery, a second metal layer arranged on the outer periphery, and an insulating layer interposed between the first and second metal layers and covering the entire antenna body, with the first metal layer forming either the ground or the antenna element, and the second metal layer forming the other of the ground or the antenna element.

In the present invention, the antenna body is constructed by laminating, from the inner periphery toward the outer periphery, a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, and a third insulating layer, with the first metal layer forming either the ground or the antenna element, and the second metal layer forming the other of the ground or the antenna element.

In this invention, the antenna body is constructed by stacking two insulating metal sheets, each metal sheet coated with an insulating layer, with the metal sheet of the insulating metal sheet located on the inner periphery forming either the ground or the antenna element, and the metal sheet of the insulating metal sheet located on the outer periphery forming either the ground or the antenna element.

In this invention, a connection terminal electrically connected to a circuit board is provided at one end of the insulating metal sheet at a position offset from the longitudinal centerline of the insulating metal sheet. One insulating metal sheet is turned over and placed on top of the other insulating metal sheet, with the connection terminal of the insulating metal sheet located on the inner periphery forming either the ground terminal or the antenna terminal, and the connection terminal of the insulating metal sheet located on the outer periphery forming the other ground terminal or the antenna terminal.

In this invention, the object to be worn is the operator's arm or part of the robot.

As described above, the present invention has the effect of enabling the position of the object being worn or the object to be detected to be detected accurately and reliably.

1 is a diagram showing a state in which a wearable antenna device according to a first embodiment of the present invention is worn on a person's wrist and in use. FIG. 2 is a front view of the wearable antenna device (FIG. 1). FIG. 3 is a side view (left side view, i.e., view taken along arrow III) of the wearable antenna device (FIG. 2). FIG. 3 is a plan view of the wearable antenna device (FIG. 2). FIG. 3 is a bottom view of the wearable antenna device (FIG. 2). FIG. 3 is a perspective view of the wearable antenna device (FIG. 2) as viewed obliquely from below. FIG. 3 is a perspective view of the wearable antenna device (FIG. 2) viewed obliquely from above. 3 is a cross-sectional schematic diagram showing the internal structure of the wearable antenna device (FIG. 2) shown together with a person's wrist. FIG. FIG. 9 is a development view of the wearable antenna device (FIG. 8) in a developed state. FIG. 10 is an enlarged partial view of the antenna portion of the wearable antenna device (FIG. 9). 2 is a perspective view of the entire wearable antenna device (FIG. 1) showing a circuit board inside the device body and an antenna body connected thereto, as viewed from the outer periphery side. FIG. FIG. 11 is an overall perspective view of the circuit board and antenna (FIG. 10) viewed from a different angle. FIG. 11 is an overall perspective view of the circuit board and the antenna (FIG. 10) as viewed from the inner periphery side. FIG. 11 is an overall perspective view of the antenna (FIG. 10) alone. 14 is an overall perspective view of the antenna (FIG. 10) alone, as viewed from the rear side of the antenna of FIG. 13. FIG. 4A to 4C are diagrams for explaining the effects of the wearable antenna device (FIG. 1) when used as a transmitting means. 4A to 4C are diagrams for explaining the effects of the wearable antenna device (FIG. 1) when used as a receiving means. FIG. 10 is a schematic front cross-sectional view of a wearable antenna device according to a second embodiment of the present invention, which corresponds to FIG. 8 of the first embodiment. FIG. 18 is a schematic diagram showing a modified example of the wearable antenna device (FIG. 17). FIG. 10 is a schematic front cross-sectional view of a wearable antenna device according to a third embodiment of the present invention, which corresponds to FIG. 8 of the first embodiment. FIG. 19 is a schematic diagram showing a modified example of the wearable antenna device (FIG. 18). FIG. 10 is a schematic front cross-sectional view of a wearable antenna device according to a fourth embodiment of the present invention, which corresponds to FIG. 8 of the first embodiment. FIG. 20 is a development view of the antenna body of the wearable antenna device (FIG. 19). FIG. 10 is a schematic front cross-sectional view of a wearable antenna device according to a fifth embodiment of the present invention, and corresponds to FIG. 8 of the first embodiment. 21A and 21B are diagrams for explaining how to wear the wearable antenna device (FIG. 20). FIG. 10 is a schematic front cross-sectional view of a wearable antenna device according to a seventh embodiment of the present invention, which corresponds to FIG. 8 of the first embodiment. FIG. 22 is an enlarged partial view of the antenna portion of the wearable antenna device (FIG. 21), and corresponds to FIG. 9A of the first embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[First Example]
Figures 1 to 16 are diagrams for explaining a wearable antenna device (hereinafter simply referred to as "antenna device") according to a first embodiment of the present invention. Figure 1 is a diagram showing the antenna device in use, Figures 2 to 7 are external views of the antenna device when in use, Figures 8 to 9A are diagrams showing the internal structure of the antenna device, Figures 10 to 12 are external views of the circuit board and antenna, Figures 13 and 14 are external views of the antenna alone, and Figures 15 and 16 are diagrams for explaining the effects of the antenna device.

As shown in FIG. 1, antenna device 1 is a wearable terminal that can be worn on the arm (wrist P in this example) (wearing target) of a person, such as an operator of a robot (not shown) or a worker, and is a device that detects the distance to the wearing target or detected object by performing presence detection using electromagnetic properties. Antenna device 1 is capable of transmitting and/or receiving, and performs presence detection by utilizing, for example, the fact that the strength (power density) of radio waves attenuates inversely proportional to the square of the distance from the antenna. Antenna device 1 may also be configured, for example, as a capacitance sensor, etc.

As shown in FIGS. 1 to 7 , the antenna device 1 includes a device main body 2 incorporating a circuit board, and an antenna 3 having one end (fixed end) 30 ( FIG. 2 ) electrically connected to the circuit board inside the device main body 2, extending in a band-like shape in the longitudinal direction, and detachably wrapped around the outer periphery of a wrist P. The antenna device 1 further includes a detachable belt 4 extending in a band-like shape in the longitudinal direction and directly wrapped around the outer periphery of the wrist P. The belt 4 is disposed on the inner periphery of the antenna 3, and the antenna 3 is wrapped around the belt 4 from the outer periphery. The antenna 3 and the belt 4 are separable from each other. The belt 4 is preferably wider than the antenna 3 (in FIG. 3 , the width of the belt 4 is _W1 and the width of the antenna 3 is _W1 , where _W1 > _W1 ). The reason for making the width of the belt 4 wider than the width of the antenna 3 is to prevent the antenna 3 from directly contacting a person's skin when the antenna device 1 is worn.

When the antenna 3 is wrapped around the wrist P, the other end (free end) 31 (Figure 2) of the antenna 3 passes below the back surface 2b of the device main body 2 on the one end 21 side and extends to below the back surface 2b of the device main body 2 on the other end 22 side. At this time, below the back surface 2b of the device main body 2, the antenna 3 is inserted into the slit-shaped space between the back surface 2b of the device main body 2 and the belt 4.

Annular locking portions 5, 6, such as D-rings, are attached to one end 21 and the other end 22 of the device body 2, respectively. The other end 31 of the antenna 3 passes through the locking portion 5, thereby detachably locking the antenna 3 to the locking portion 5 and to the device body 2 via the locking portion 5. Locking the antenna 3 with the annular locking portions (such as D-rings) 5, 6 allows the antenna 3 to be locked without applying a strong force to it, preventing damage to the antenna 3. Although not shown, a latch mechanism may be provided below the back surface 2b of the device body 2 to clamp or tighten the other end 31 or its vicinity to prevent it from moving loose (to the left in Figure 2).

The belt 4 is made of, for example, resin (nylon, etc.), and is fastened to the fastening portions 5, 6 by passing it through them on the inner periphery of the antenna 3. The ends 4a, 4b are connected by an annular fastener (e.g., a D-ring) 40, making it endless. Therefore, the belt 4 is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction along the outer periphery of the wrist P. In the example shown in Figure 2, there is a gap between the ends 4a, 4b of the belt 4, but this gap is filled by the fastener 40. Therefore, by regarding the fastener 40 as part of the belt 4, which is a wrapping member for the wrist P, it can be said that the belt 4 is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction.

In this example, one of the ends 4a, 4b (e.g., end 4b) is a looped end secured by sewing or the like, while the other end (e.g., end 4a) is an expandable looped end secured by hook-and-loop fasteners or the like. In this case, to wear the belt 4 around the wrist P, the looped end of end 4a is expanded to expand the belt 4 (or straighten it), and then the belt 4 is wrapped around the wrist P. After that, the length of the belt 4 threaded through the fastener 40 is adjusted as needed, and the end 4a of the belt 4 is secured by hook-and-loop fasteners or the like to form a loop. Note that the structures of the belt 4 and fastener 40 are not limited to those described above, and any suitable structure may be adopted.

For example, each of the ends 4a, 4b may be a looped end secured by sewing or the like, and the fastener 40 threaded through each looped end may have a releasable locking mechanism. In this case, the belt 4 can be separated from the device main body 2 and the antenna 3 by releasing the locking mechanism of the fastener 40 and removing one end of the belt 4 from the fastener 40. The fastener 40 may also have a buckle structure (e.g., a one-touch buckle).

In the example shown in Figure 2, the other end 31 of the antenna 3 is inserted through the locking portion 5 and then positioned on the near side of the locking portion 6 (on the left side in the figure) (Specific Example 1), but the other end 31 may be inserted through not only the locking portion 5 but also the locking portion 6 (Specific Example 2). Alternatively, the other end 31 does not have to be disposed along the entire width direction of the device body 2 (left-right direction in Figure 2) along the back surface 2b of the device body 2, but may be positioned intermediately between the locking portions 5 and 6 below the back surface 2b of the device body 2 (Specific Example 3).

In the case of the above specific example 2, the other end 31 of the antenna 3 is positioned below the one end 30 and overlaps the one end 30 in the vertical direction, so the antenna 3 is wrapped around the wrist P alone (i.e., alone) without any gaps in the circumferential direction around the outer periphery of the wrist P at least once; in other words, it can be said to surround the wrist P at least once. Note that in this specification, "without any gaps in the circumferential direction" for the antenna 3 alone means that the antenna 3 wrapped around the wrist P has no gaps in the circumferential direction (i.e., in the longitudinal direction), i.e., the antenna 3 is wrapped around the wrist P alone at least once, and does not mean that there are no gaps in the circumferential direction between the antenna 3 and the belt 4 (or the arm P).

In the above specific examples 1 and 3, the other end 31 of the antenna 3 does not overlap the one end 30 in the vertical direction, and it cannot be said that the antenna 3 alone is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction, but a circuit board is positioned above the gap (i.e., the missing part) between the other end 31 and the one end 30 of the antenna 3 and overlaps this gap in the vertical direction. Therefore, in this case, the antenna 3, together with the circuit board (i.e., working together with the circuit board), is wrapped around the entire circumference of the wrist P (at least one full revolution) without any gaps in the circumferential direction, or in other words, it surrounds the wrist P at least once. In this specification, "without a gap in the circumferential direction" in conjunction with the circuit board means that the antenna 3 wrapped around the wrist P cooperates with the circuit board to create no gap in the circumferential direction (i.e., the longitudinal direction), i.e., the antenna 3 is wrapped around the wrist P together with the circuit board at least once, but does not mean that there is no gap in the circumferential direction between the antenna 3 and the circuit board and the belt 4 (or arm P).

The portion of the antenna 3 located below the back surface 2b of the device main body 2 is not only necessary for fastening the antenna 3 around the wrist P, but also corresponds to the excess length of the antenna 3, and serves to accommodate individual differences in the circumference of the wrist P on which the antenna device 1 is worn. For people with thin wrists P, the excess length of the antenna 3 will be long, while for people with thick wrists P, the excess length of the antenna 3 will be short. In particular, for people with thick wrists, it is thought that the above specific examples 1 and 3 will often apply. In such cases, as described above, the antenna 3, together with the circuit board (i.e., working in cooperation with the circuit board), will be wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction.

Next, Figure 8 shows the internal structure of the antenna device 1 shown in Figure 2 together with the wrist P, Figure 9 shows the antenna body 3 of the antenna device 1 in an unfolded state, and Figure 9A is an enlarged partial view of the antenna body 3. In these figures, the same reference numerals as in Figure 2 indicate the same or equivalent parts. In Figures 8 and 9, the locking portions 5, 6 and fastener 40 are omitted, and for ease of illustration, the gaps between each part are exaggerated.

As shown in Figures 8 and 9, a circuit board 20 is disposed inside the device body 2 of the antenna device 1. Units that enable the antenna device 1 to transmit and/or receive signals are appropriately mounted on the circuit board 20. One end 30 of the antenna body 3 is electrically connected to the circuit board 20. The antenna body 3 has a two-layer structure formed by laminating a ground layer 30G, which is disposed on the inner periphery and is made of a first metal layer that forms the ground, and an antenna layer 30A, which is disposed on the outer periphery and is made of a second metal layer that forms the antenna element.

An insulating layer 30S is attached to the entire antenna body 3, i.e., to the inner and outer peripheral surfaces and the end face (i.e., the end face of the other end 31). Furthermore, a similar insulating layer 30S is also interposed at the interface between the ground layer (first metal layer) 30G and the antenna layer (second metal layer) 30A.
9A , the antenna 3 is configured by laminating, in order from the inner circumferential side (bottom side in the figure) to the outer circumferential side (top side in the figure), a first insulating layer _30S1 , a ground layer 30G constituting the ground, a second insulating layer _30S2 , an antenna layer _30A constituting the antenna element, and a third insulating layer 30S3. Alternatively, the antenna 3 may be fabricated by laminating insulating layers over the entire surfaces of the antenna layer 30A and the ground layer 30G and integrating the two layers with an insulating layer interposed therebetween. In this case, if the same metal layer is used for the antenna layer 30A and the ground layer 30G, the structure can be further simplified and costs can be reduced.

Next, Figures 10 and 11 are overall perspective views of the circuit board 20 built into the device body 2 of the antenna device 1 and the antenna 3 electrically connected thereto, as viewed from the outer periphery. Figure 12 is an overall perspective view of the circuit board 20 and the antenna 3 as viewed from the inner periphery. Figures 13 and 14 are overall perspective views of the antenna 3 alone. Note that in Figures 10 and 11, the third insulating layer _30S3 disposed on the outermost layer on the outer periphery of the antenna 3 is omitted, and in Figure 12, the first insulating layer _30S1 disposed on the innermost layer on the inner periphery of the antenna 3 is omitted. Furthermore, Figure 14 shows the antenna 3 of Figure 13 turned upside down. In each figure, the same reference numerals as in Figures 1 to 9A indicate the same or corresponding parts.

The antenna 3 shown in Fig. 10 is constructed by flipping two insulating metal sheets 3A and 3B, each having the same shape and structure, and superimposing one on the other. The two insulating metal sheets 3A and 3B will now be described with reference to Figs. 13 and 14. Note that in Fig. 13, the insulating layers _30S1 and _30S3 on the surfaces (the surfaces facing the viewer) of the insulating metal sheets 3A and 3B are omitted.

One end of each insulating metal sheet 3A, 3B is provided with a pair of left and right mounting tabs 32, 33 positioned offset from the longitudinal centerline CL (i.e., asymmetrical). Each tab 32, 33 has a through-hole 32a, 33a into which a mounting screw (described below) is inserted to secure each insulating metal sheet 3A, 3B to the circuit board 20. Each insulating metal sheet 3A, 3B has a metal sheet 30A, 30G, respectively, on its front surface (see FIG. 13). Each metal sheet 30A, 30G has an antenna terminal (connection terminal) 30At and a ground terminal (connection terminal) 30Gt, respectively, at positions corresponding to the mounting tabs 33. The back surface of each metal sheet 30A, 30G (see FIG. 14) is covered with an insulating layer _30S2 .

To assemble the antenna 3, one of the two insulating metal sheets 3A, 3B (e.g., insulating metal sheet 3B) is turned over (see FIG. 14) and placed on the back side of the other insulating metal sheet 3A (see FIG. 13) (i.e., the insulating layers _30S2 of both insulating metal sheets 3A, 3B are placed on top of each other). At this time, because the mounting tabs 32, 33 of each insulating metal sheet 3A, 3B are offset from the longitudinal center line CL, the mounting tabs 32, 33 of the placed insulating metal sheets 3A, 3B are positioned as shown in FIG. 10 without overlapping each other.

From this state, long nuts 23 are placed between the circuit board 20 and each insulating metal sheet 3A, 3B at positions corresponding to the through holes 32a, 33a, and mounting screws 24' inserted into the through holes 32a, 33a from the inner periphery of the antenna 3 are threaded into the nuts 23 (see Figure 12). Meanwhile, multiple through holes (not shown) are formed at one end of the circuit board 20 at positions corresponding to the through holes 32a, 33a of each insulating metal sheet 3A, 3B. Mounting screws 24 inserted into these through holes from the outer periphery of the antenna 3 are threaded into the corresponding nuts 23 (see Figure 10). With this configuration, the insulating metal sheets 3A, 3B are screwed to the circuit board 20. In this way, the antenna terminal 30At of the metal sheet 30A is electrically connected to the circuit board 20, and the ground terminal 30Gt of the metal sheet 30G is electrically connected to the circuit board 20, achieving a strong connection by screwing (note that fastening by means other than screwing may also be used). The circuit board 20 is then placed inside the device main body 20.

Next, the effects of this embodiment will be described with reference to FIGS. 15 and 16. FIG.
Here, we envision a work site where people (workers) and robots work together.
15 shows an example in which the antenna device 1 is used as a transmitting means, and the antenna device 1 is worn, for example, on the wrist of a worker. In the figure, the circular area indicated by the symbol Ef indicates the (AC) electromagnetic field formed by the antenna device 1. The electromagnetic field Ef is formed evenly in all directions, 360 degrees around the antenna device 1. Furthermore, the symbols _T1 and _T2 indicate a detected object (detection target) such as a robot, as a receiving means.

When robot _T1 enters the electromagnetic field Ef of antenna device 1 worn on the wrist of a worker working with a collaborative robot, the receiving means on robot T1 measures the reception strength and, based on the measurement results, calculates the distance d between robot _T1 and antenna device 1, utilizing the fact that the strength of radio waves (power _density ) attenuates inversely proportional to the square of the distance from the antenna. On the other hand, robot _T2 is located outside the electromagnetic field Ef of antenna device 1, and therefore is not detected by the receiving means on robot _T2 .

In Figure 15, contrary to the example described above, the antenna device 1 may be attached to a robot and used to detect a person as the object to be detected (detection target).

16 shows an example in which the antenna device 1 is used as a receiving means. The antenna device 1 is worn, for example, on the wrist of a worker, and a detection region Df is formed around the antenna device 1, evenly extending in all directions of 360 degrees. Furthermore, symbols _T1 , _T1 ', and _T2 indicate objects to be detected (detection targets), such as a robot, as a transmitting means.

When robot _T1 enters the detection area Df of antenna device 1 worn on the worker's wrist while working with a collaborative robot, the reception strength of the radio waves emitted by the transmitting means on robot _T1's side is measured, and based on the measurement results, the distance d between robot _T1 and antenna device ₁ is calculated by utilizing the fact that the strength of the radio waves (power density) attenuates inversely proportional to the square of the distance from the antenna. Similarly, the distance d' between robot _T1 ' and antenna device 1 is calculated for robot T1'. On the other hand, robot _T2 is located outside the detection area Df of antenna device 1, so robot _T2 is not detected.

As described above, according to this embodiment, the antenna 3, either alone or together with the device main body 2, can be wrapped around the entire circumference of the wrist P without gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave strength in all directions (360 degrees) around the antenna 3 (i.e., in all circumferential directions). This prevents radio wave strength from changing depending on the orientation of the wrist P or the object to be detected, and as a result, the position of the object to be worn or the object to be detected can be detected accurately and reliably.

In this embodiment, the antenna 3 is constructed by flipping one of two insulating metal sheets over and placing it on top of the other, so only one type of metal sheet is required, thereby reducing manufacturing costs.

According to this embodiment, by arranging the belt 4 on the inner circumferential side of the antenna 3 (and preferably by making the belt 4 wider than the antenna 3), the following effects are achieved.
i) By preventing the antenna 3 from coming into direct contact with the wrist P, the risk of electric shock due to a malfunction can be avoided.
ii) The generation of an electric field between the antenna layer 30A and the ground layer 30G can suppress the absorption of radio waves into the human body, thereby realizing uniform radio wave strength in the surroundings.
iii) The rigidity of the belt 4 can absorb the pressure that is generated toward the outside of the wrist when the hand, wrist, or arm is moved while wearing the device, thereby preventing pressure from acting directly on the antenna 3 and improving durability.
iv) Since it is the belt 4, not the antenna 3, that comes into direct contact with the skin, if the belt 4 becomes dirty, it can be separated from the antenna 3 and washed separately, improving convenience. Also, even when the antenna device 1 is shared with other people, it is hygienic if each person has their own belt 4 to wear for private use. Furthermore, using belts of specific colors depending on the type of collaborative robot, etc., makes it easier to ensure thorough safety management.

Second Example
In the first embodiment, the other end 31 of the antenna 3 is disposed below the rear surface 2b of the device body 2 (see FIG. 8), but the application of the present invention is not limited to this. Figure 17 shows a wearable antenna device according to a second embodiment of the present invention, and in this figure, the same reference numerals as in the first embodiment indicate the same or corresponding parts.

As shown in FIG. 17 , in the wearable antenna device 1 according to the second embodiment, the other end 31 of the antenna 3 extends to a position where it abuts against one end 21 of the device body 2 and is not disposed below the rear surface 2b of the device body 2. While a gap is shown between the other end 31 of the antenna 3 and the one end 21 of the device body 2 in the figure, this is provided for convenience of illustration. In this embodiment, the other end 31 of the antenna 3 abuts against the one end 21 of the device body 2, and no gap is formed between the other end 31 and the one end 21. Furthermore, to maintain the other end 31 abutting against the one end 21, a locking portion for locking the other end 31 to the one end 21 may be provided. For example, the locking portion may be formed by forming a recess or a tapered slit in the one end 21, and fitting the other end 31 into the recess or slit to lock it.

In the second embodiment, as in the first embodiment, the antenna 3, together with the device main body 2, is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave strength in all directions (360 degrees) around the antenna 3. This prevents radio wave strength from changing depending on the orientation of the wrist P or the object to be detected, and as a result, the position of the object to be worn or the object to be detected can be detected accurately and reliably.

Figure 17A shows a schematic diagram of a modified example of the second embodiment. In this modified example, the other end 31 of the antenna 3 passes through a slit formed in one end 21 of the device body 2 and extends to the inside of the device body 2. The other end 31 is disposed inside the device body 2, for example, above a circuit board (not shown).

In this case, the antenna 3, together with the device main body 2, can be wrapped around the entire circumference of the wrist without any gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave intensity in all directions (360 degrees) around the antenna 3, thereby achieving the same effects as in the first embodiment.

[Third Example]
In the first embodiment, the other end 31 of the antenna 3 is disposed below the rear surface 2b of the device body 2 (see FIG. 8), but the application of the present invention is not limited to this. Figure 18 shows a wearable antenna device according to a third embodiment of the present invention, and in this figure, the same reference numerals as in the first embodiment indicate the same or corresponding parts.

As shown in Figure 18, in the wearable antenna device 1 according to the third embodiment, the other end 31 of the antenna 3 passes above the top surface (surface) 2a of the device body 2 and extends to a position beyond one end 30 of the antenna 3. A possible locking portion for locking the other end 31 to the device body 2 is, for example, a hook-and-loop fastener or the like that can be used to detachably lock the other end 31 to the top surface 2a of the device body 2.

In the third embodiment, as in the first embodiment, the antenna 3 is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave strength in all directions (360 degrees) around the antenna 3. This prevents radio wave strength from changing depending on the orientation of the wrist P or the object to be detected, and as a result, the position of the object to be worn or the object to be detected can be detected accurately and reliably.

Figure 18A shows a schematic diagram of a modified version of the third embodiment. In this modified version, the other end 31 of the antenna 3 is disposed above the top surface 2a of the device body 2 and is anchored to the top surface 2a.

In this case, the antenna 3, together with the device main body 2, is wrapped around the entire circumference of the wrist without any gaps in the circumferential direction, creating an electromagnetic field and detection area with uniform radio wave intensity in all directions (360 degrees) around the antenna 3, thereby achieving the same effects as the first embodiment.

[Fourth Example]
In the first embodiment, one end 30 of the antenna body 3 is a fixed end fixed to a circuit board inside the device main body 2, and the other end 31 is a free end, but the application of the present invention is not limited to this.

Figures 19 and 19A are diagrams illustrating a wearable antenna device according to a fourth embodiment of the present invention. Figure 19 shows the wearable antenna device wrapped around the wrist P, and Figure 19A is an exploded view of the antenna body of the wearable antenna device in an expanded state. In these figures, the same reference numerals as in the first embodiment indicate the same or equivalent parts.

In this fourth embodiment, the longitudinal center portion of the antenna 3 is a fixed end fixed to the circuit board 20 inside the device main body 2, and both longitudinal ends 31A, 31B of the antenna 3 are free ends. In this case, by overlapping the free ends 31A, 31B, the antenna 3, together with the circuit board (i.e., working in cooperation with the circuit board), is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction.

In the fourth embodiment, in the overlapping portion of each free end 31A, 31B of the antenna body 3 (see FIG. 19), the [first insulating layer, ground layer, second insulating layer, antenna layer, third insulating layer] at the outer free end 31B is superimposed on the [first insulating layer, ground layer, second insulating layer, antenna layer, third insulating layer] at the inner free end 31A from the inner periphery toward the outer periphery (from the top to the bottom of the overlapping portion in the figure). Therefore, in this case, the ground layer of the outer free end is positioned immediately above the antenna layer of the inner free end, so the overlapping of the antenna bodies 3 has almost no effect on the radio wave intensity, and is at a level that can be ignored in practical use. This also applies to the overlapping portion in Specific Example 2 (see paragraph [0030]) described in the first embodiment.

Fifth Example
In the first embodiment, one end 30 of the antenna body 3 is a fixed end fixed to a circuit board inside the device main body 2, and the other end 31 is a free end, but the application of the present invention is not limited to this.

Figures 20 and 20A show a wearable antenna device according to a fifth embodiment of the present invention, with Figure 20 showing the wearable antenna device wrapped around the wrist P, and Figure 20A illustrating the wrapping operation when wrapping the wearable antenna device around the wrist P. These figures show parts that are the same as or equivalent to those of the first embodiment.

In this fifth embodiment, the central longitudinal portion of the antenna 3 is a fixed end fixed to the circuit board 20 inside the device main body 2, and in this state the antenna 3 is in a seamless, endless state, so the antenna 3 has no free ends.

Even in this case, the antenna 3, together with the circuit board (i.e., working in cooperation with the circuit board), is wrapped around the entire circumference of the wrist P without any gaps in the circumferential direction along the outer periphery of the wrist P. In the example shown in Figure 20, the antenna 3 is made of a stretchable member. Therefore, when wearing the antenna device 1 on the wrist P, as shown in Figure 20A, the endless antenna 3 is expanded radially outward (i.e., its diameter is expanded), and then the antenna 3 is worn in this state over the belt 4 wrapped around the wrist P.

Sixth Example
In the first embodiment, the antenna body 3 shown in Figure 10 is constructed by flipping one of two insulating metal sheets 3A, 3B having the same shape and structure over the other, but the application of the present invention is not limited to this.

When one of the two insulating metal sheets 3A, 3B is flipped over and placed on top of the other, a silicone sheet may be sandwiched between the two insulating metal sheets 3A, 3B. This configuration allows the distance between the antenna layer 30A and the ground layer 30G to be further increased, further separating the layers, thereby reducing the effect of parasitic capacitance that occurs between the antenna layer 30A and the ground layer 30G. Alternatively, a void (air layer) may be formed within the silicone sheet to provide an insulating effect via the air.

Furthermore, two insulating metal sheets 3A, 3B having the same shape and structure may not be made exactly the same shape, and the width of either the antenna layer 30A or the ground layer 30G of the insulating metal sheets 3A, 3B may be made narrower. In this case, by reducing the surface area of the antenna layer 30A or the ground layer 30G, the effect of parasitic capacitance occurring between the antenna layer 30A and the ground layer 30G can be reduced. Note that since the antenna layer affects the strength of radio waves, it is preferable to maintain the strength of radio waves while reducing the effect of parasitic capacitance by making the width of the ground layer 30G narrower rather than making the width of the antenna layer 30A narrower.

Seventh Example
In the first embodiment, as shown in FIG. 9A , an example has been shown in which the antenna 3 is configured by laminating, in order from the inner circumferential side (lower side in the figure) to the outer circumferential side (upper side in the figure), a first insulating layer _30S1 , a ground layer 30G constituting the ground, _a second insulating layer 30S2, an antenna layer _30A constituting the antenna element, and a third insulating layer 30S3, but the application of the present invention is not limited to this.

Figures 21 and 21A show a wearable antenna device according to a seventh embodiment of the present invention, with Figure 21 showing the wearable antenna device wrapped around the wrist P and Figure 21A being an enlarged partial view of the antenna body 3. In these figures, the same reference numerals as those in the first embodiment indicate the same or corresponding parts.

21 and 21A , when the ground layer is arranged on the outer periphery and the antenna layer is arranged on the inner periphery within the substrate 20, the outermost layer is the ground layer when considering the entire device body 2. Therefore, when the antenna 3 is constructed by laminating, in order from the inner periphery to the outer periphery, a first insulating layer _30S1 , an antenna layer 30A constituting the antenna element, a second insulating layer _30S2 , a ground layer 30G constituting the ground, and a third insulating layer _30S3 , the arrangement order of the antenna layer and the ground layer can be made uniform over the entire periphery, thereby achieving more uniform radio wave intensity.

If the outer periphery of the substrate 20 is an antenna layer, the antenna 3 can be arranged in the same order as in the first embodiment, thereby aligning the arrangement order of the antenna layer and ground layer on the substrate 20 and the antenna 3.

Also, a silicon sheet may be added to the inner peripheral side of the first insulating layer 30S _1. The silicon sheet may be disposed over the entire circumferential direction, or may be disposed only in locations where there is a high possibility of overlapping between antennas 3. Furthermore, the configuration for reducing the influence of parasitic capacitance, as explained in the sixth embodiment, may be applied to this seventh embodiment.

[Other Modifications]
In the first to seventh embodiments and their modifications, examples have been shown in which only the antenna 3 and the device main body 2 are used as an antenna, but the application of the present invention is not limited to this. For example, it is also possible to configure a different type of antenna by connecting a portion of the antenna 3 to an external conductor via a connector or the like. In this case, for example, if the wearer wears clothing configured using a stretchable conductive sheet or the like as the external conductor, the clothing itself can be used as an antenna capable of outputting radio waves.

[Other application examples]
In the first to fifth embodiments and the modifications, the wearable antenna device according to the present invention is described as being worn on the wrist P of a person such as a worker, but the application of the present invention is not limited to this. The antenna device may also be worn on other parts of the person's body (for example, the forearm or upper arm excluding the wrist).

The wearable antenna device according to the present invention may also be mounted on a robot arm, or may be mounted, for example, on the bumper of an automatic transport robot such as an AGV (Automatic Guided Vehicle) or an AMR (Autonomous Mobile Robot). In this specification, these are collectively referred to as "part of the robot." When applied to an automatic transport robot, the antenna device may be mounted on an obstacle such as a pillar or wall inside a warehouse or building, rather than on the robot's bumper. In either case, the antenna device will be able to detect when the automatic transport robot is approaching an obstacle.

Other Examples and Modifications
The above-described embodiments and modifications are to be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains will be able to devise various modifications and other embodiments that incorporate the principles of the present invention, even if not expressly described herein, without departing from the spirit and essential characteristics of the present invention, when taking into account the teachings set forth above.

As described above, the present invention is useful for wearable antenna devices, and is particularly suited to wearable antenna devices for accurately and reliably detecting the position of the object to be worn or the object to be detected.

1: Antenna device (wearable antenna device)

2: Device body 20: Circuit board 2b: Back side

3: Antenna body 3A, 3B: Insulated metal sheet 30: One end (fixed end)
31: Other end (free end)
30A: Antenna layer (second metal layer)
30At: Antenna terminal (connection terminal)
30G: Ground layer (first metal layer)
30Gt: Ground terminal (connection terminal)
30S: Insulating layer 30S ₁ : First insulating layer 30S ₂ : Second insulating layer 30S ₃ : Third insulating layer

4: Belt

5, 6: Locking portion

P: Wrist (wearing target)

Japanese Patent No. 3254880 (see claim 1, paragraphs [0001], [0005], [0011] to [0013], [0031], [0034], and [0045], Figures 1 to 3, 4(a), and 8)

Claims (9)

A wearable antenna device that is attachable to an object and detects the presence of the object by utilizing electromagnetic properties,
a device body incorporating a circuit board;
an antenna body, at least a portion of which is electrically connected to the circuit board as a fixed end, and which can be wrapped around the entire circumference of the object to be attached without any gaps in the circumferential direction along the outer periphery of the object to be attached, either together with the device main body or alone;
A wearable antenna device comprising: In claim 1,
the part of the antenna body is one end of the antenna body, the one end being the fixed end electrically connected to the circuit board, and the other end of the antenna body being a free end, and in a state where the antenna body is wrapped around the outer periphery of the attachment target, the antenna body on the other end side can be passed through the back side of the device body and engaged with the device body;
A wearable antenna device. In claim 1,
The device further includes a belt that is disposed on the inner periphery of the antenna body, is provided so as to be engageable with and detachable from the device body via a locking portion, and can be wound around the entire circumference of the object to be worn without any gaps in the circumferential direction along the outer periphery of the object to be worn, and the antenna body disposed on the outer periphery of the belt can be engaged with and detached from the locking portion.
A wearable antenna device. In claim 1,
the antenna body has a first metal layer disposed on an inner circumferential side and a second metal layer disposed on an outer circumferential side,
the first metal layer constitutes one of a ground and an antenna element, and the second metal layer constitutes the other of the ground and the antenna element;
A wearable antenna device. In claim 1,
the antenna body is composed of a first metal layer disposed on the inner circumferential side, a second metal layer disposed on the outer circumferential side, and an insulating layer interposed between the first metal layer and the second metal layer and covering the entire antenna body, the first metal layer forming one of a ground or an antenna element, and the second metal layer forming the other of the ground or the antenna element;
A wearable antenna device. In claim 1,
the antenna body is configured by laminating a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, and a third insulating layer from the inner circumferential side toward the outer circumferential side, the first metal layer forming one of the ground and the antenna element, and the second metal layer forming the other of the ground and the antenna element;
A wearable antenna device. In claim 1,
The antenna body is configured by stacking two insulating metal sheets, each of which is covered with an insulating layer, and the metal sheet of the insulating metal sheet arranged on the inner circumferential side constitutes either the ground or the antenna element, and the metal sheet of the insulating metal sheet arranged on the outer circumferential side constitutes the other of the ground or the antenna element.
A wearable antenna device. In claim 7,
A connection terminal electrically connected to the circuit board is provided at one end of the insulating metal sheet at a position offset from the center line of the insulating metal sheet in the longitudinal direction, and one of the insulating metal sheets is turned over and placed on the other of the insulating metal sheets, with the connection terminal of the insulating metal sheet located on the inner periphery forming one of the ground terminal or antenna terminal, and the connection terminal of the insulating metal sheet located on the outer periphery forming the other of the ground terminal or antenna terminal.
A wearable antenna device. In claim 1,
The attachment target is a part of an operator's arm or a robot.
A wearable antenna device.