Communication system

Abstract

To reduce interference in communication without providing a shield in two-way communications, and improve communication quality and reduce the size of a communication system.SOLUTION: A first communication device has an arc-shaped first transmission electrode arranged on the circumference of a first circle, and an arc-shaped second reception electrode arranged on the circumference of the first circle. The second communication device has a plurality of arc-shaped first reception electrodes arranged on the circumference of a second circle, and a plurality of arc-shaped second transmission electrodes arranged on the circumference of the second circle. The first communication device and the second communication device are rotatable relative to each other around a rotation axis, which is a line connecting the central point of the first circle and the central point of the second circle to each other. The first transmission electrode and at least one first reception electrode of the plurality of first reception electrodes are arranged to face each other, and perform non-contact communication. At least one second transmission electrode of the plurality of second transmission electrodes and the second reception electrode are arranged to face each other, and perform non-contact communication.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a communication system.

Background Art

[0002] In recent years, communication devices that perform communication using electromagnetic field coupling between a rotating part and a fixed part, such as a joint part of a robot arm or a coupling part between a network camera and a pan-tilt unit, are known.

[0003] For example, Patent Document 1 discloses a technique for performing electromagnetic field communication by opposing an electrode provided on a substrate of a fixed part and an electrode on a substrate of a rotating part provided with a space from the substrate of the fixed part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, two (four in differential) electrodes arranged in parallel on one substrate and two (four in differential) electrodes arranged in parallel on the other substrate are provided, and bidirectional communication is realized by performing electromagnetic field communication respectively.

[0006] However, there is a problem that one electromagnetic field communication interferes with the other electromagnetic field communication and deteriorates the communication quality. In particular, when the transmission electrode and the reception electrode run parallel to each other, crosstalk noise increases, so the interference becomes large and the communication quality deteriorates. Therefore, by arranging a GND electrode that functions as a shield between the transmission electrode and the reception electrode, the electromagnetic field is blocked and the interference is reduced, thereby suppressing the deterioration of the communication quality.

[0007] However, while the GND electrode can block the electromagnetic field interfering via the GND electrode, it cannot block the electromagnetic field interfering through the space other than the GND electrode, so the effect of interference reduction is limited. In addition, providing the GND electrode may increase the substrate size and lead to an increase in the device scale.

[0008] An object of the present disclosure is to reduce communication interference without providing a shield in bidirectional communication, and to realize improvement in communication quality and miniaturization of the communication system.

Means for Solving the Problems

[0009] A communication system includes a first communication device and a second communication device. The first communication device has an arc-shaped first transmission electrode disposed on the circumference of a first circle and an arc-shaped second reception electrode disposed on the circumference of the first circle. The second communication device has a plurality of arc-shaped first reception electrodes disposed on the circumference of a second circle and a plurality of arc-shaped second transmission electrodes disposed on the circumference of the second circle. The first communication device and the second communication device are relatively rotatable about a line connecting the center point of the first circle and the center point of the second circle as a rotation axis. The first transmission electrode and at least one of the plurality of first reception electrodes are arranged to face each other to perform non-contact communication, and at least one of the plurality of second transmission electrodes and the second reception electrode are arranged to face each other to perform non-contact communication.

Effects of the Invention

[0010] According to the present disclosure, in bidirectional communication, it is possible to reduce communication interference without providing a shield, and to realize improvement in communication quality and miniaturization of the communication system.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments will be described with reference to the drawings.

[0013] [First Embodiment] FIG. 1 is a block diagram showing an example of the configuration of a communication system 100 according to the first embodiment. The communication system 100 includes a fixed-side communication device 200, a rotating-side communication device 300, and a rotation control unit 101, and performs electromagnetic field communication using electromagnetic field coupling between the fixed-side communication device 200 and the rotating-side communication device 300.

[0014] The rotation control unit 101 is constituted by a motor or the like, and controls the electrodes on the fixed-side communication device 200 and the electrodes on the rotating-side communication device 300, which face each other with a space therebetween on substantially the same axis, to rotate relative to each other about the axis.

[0015] In this embodiment, the case where the rotating-side communication device 300 rotates will be described. However, as long as the electrodes rotate relative to each other about a predetermined axis, it is not limited. The electrodes on the fixed-side communication device 200 may be rotated about the axis, or both the electrodes on the fixed-side communication device 200 and the rotating-side communication device 300 may be rotated.

[0016] Also, as long as the electrodes rotate relative to each other about a predetermined axis, it is not necessary to rotate the entire fixed-side communication device 200 and the rotating-side communication device 300. Note that the fixed-side communication device 200 and the rotating-side communication device 300 may be the first part and the second part of a single communication device, respectively, or may be separate devices.

[0017] The electromagnetic field coupling in this embodiment includes both electric field coupling and magnetic field coupling. That is, the electromagnetic field communication between the electrodes may be performed by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling. In this embodiment, the case where electric field coupling is performed between the electrodes and non-contact communication is performed will be mainly described.

[0018] The fixed-side communication device 200 includes a first transmission circuit 201, a first transmission electrode 202, a second reception electrode 203, and a second reception circuit 204. The rotating-side communication device 300 includes a plurality of first reception electrodes 301, a first reception circuit 302, a second transmission circuit 303, and a plurality of second transmission electrodes 304.

[0019] The first transmission circuit 201 transmits a signal to the first transmission electrode 202. The first transmission electrode 202 performs electric field coupling by facing the lowest one of the plurality of first reception electrodes 301, and transmits the signal received from the first transmission circuit 201 to the electrode that is performing electric field coupling.

[0020] The plurality of first reception electrodes 301 transmit the signal received from the first transmission electrode 202 to the first reception circuit 302. The first reception circuit 302 synthesizes the signals received from the plurality of first reception electrodes 301 by a synthesizer 311 in FIG. 2(b) or the like, and restores the signal transmitted from the first transmission circuit 201.

[0021] Examples of the restoration means of the first reception circuit 302 include a comparator circuit 309 in FIG. 2(b), but restoration may also be performed by other circuits. For example, when a rectangular wave signal is output from the first transmission circuit 201, a differential waveform signal is input to the first reception circuit 302 via the electric field coupling between the first transmission electrode 202 and the plurality of first reception electrodes 301. By providing a comparator circuit 309 in the first reception circuit 302 for this differential waveform signal, the signal can be restored. Note that the signal restoration may also be performed by other circuits. Thereby, one-way non-contact communication for transmitting a signal from the fixed-side substrate 207 in FIG. 2(a) to the rotating-side substrate 307 in FIG. 2(b) without contact is performed.

[0022] The second transmission circuit 303 is composed of a signal source 305, a distributor 310, etc. in FIG. 2(b), and transmits signals to a plurality of second transmission electrodes 304. Note that the configuration of the second transmission circuit 303 is not limited to this. For example, the second transmission circuit 303 may use a signal source with a fan-out function, or may include a plurality of signal sources that transmit the same signal.

[0023] Among the plurality of second transmission electrodes 304, the lowest one of the plurality of second transmission electrodes 304 is capacitively coupled by facing the second reception electrode 203, and transmits the signal received from the second transmission circuit 303 to the second reception electrode 203.

[0024] The second reception electrode 203 transmits the signal received from the plurality of second transmission electrodes 304 to the second reception circuit 204. The second reception circuit 204 receives the signal from the second reception electrode 203 and restores the signal transmitted from the second transmission circuit 303.

[0025] Thereby, one-way non-contact communication for transmitting a signal from the rotating-side substrate 307 in FIG. 2(b) to the fixed-side substrate 207 in FIG. 2(a) without contact is performed, and two-way communication is realized in combination with the non-contact communication from the fixed-side substrate 207 to the rotating-side substrate 307 described above.

[0026] Next, with reference to FIGS. 2(a) to 2(d), the elements and positional relationships of each block will be described. FIG. 2(a) is a diagram showing a configuration example of the fixed-side communication device 200.

[0027] The fixed-side communication device 200 has a fixed-side substrate 207. The first transmission circuit 201 has a signal source 205 and a differential buffer 206. The first transmission electrode 202 has first transmission electrodes 202-1 and 202-2. The second reception electrode 203 has second reception electrodes 203-1 and 203-2. The second reception circuit 204 has a comparator circuit 209.

[0028] As shown in FIG. 2(a), the signal source 205 transmits a signal to the differential buffer 206. Based on the received signal, the differential buffer 206 transmits a differential signal to the first transmission electrodes 202-1 and 202-2.

[0029] The first transmission electrodes 202-1 and 202-2 formed on the first circles 208-1 and 208-2 on the fixed-side substrate 207 receive the differential signal from the differential buffer 206. The inner first transmission electrode 202-1 is formed in an arc shape on the inner first circle 208-1. The outer first transmission electrode 202-2 is formed in an arc shape on the outer first circle 208-2.

[0030] The fixed-side substrate 207 can be a rigid substrate such as FR4 or a flexible substrate, and electrodes can be formed with copper patterns. A positive-phase signal is input to the inner first transmission electrode 202-1, and a reverse-phase signal is input to the outer first transmission electrode 202-2.

[0031] The second reception electrodes 203-1 and 203-2 formed on the first circles 208-1 and 208-2 on the fixed-side substrate 207 transmit a differential signal to the comparator circuit 209 in the second reception circuit 204. The comparator circuit 209 restores the voltage generated in the second reception electrodes 203-1 and 203-2 by electric field coupling into an electric signal in response to the input of the electric signal to the second reception electrodes 203-1 and 203-2.

[0032] The inner second reception electrode 203-1 is formed in an arc shape on the inner first circle 208-1. The outer second reception electrode 203-2 is formed in an arc shape on the outer first circle 208-2. A positive-phase signal is input to the inner first transmission electrode 202-1, and a reverse-phase signal is input to the outer first transmission electrode 202-2.

[0033] At this time, when electromagnetic field coupling occurs between the first transmission electrode 202 and the second reception electrode 203, the interference noise increases. However, since the first transmission electrode 202 and the second reception electrode 203 are not arranged in parallel, the interference noise can be reduced without providing a ground (GND) electrode.

[0034] Figure 2(b) is a diagram showing a configuration example of the communication device 300 on the rotating side. The communication device 300 on the rotating side has a rotating-side substrate 307. The first receiving circuit 302 has two synthesizers 311 and a comparator circuit 309. The second transmitting circuit 303 has a signal source 305, a differential buffer 306, and two distributors 310.

[0035] As shown in Figure 2(b), the signal source 305 transmits a signal to the differential buffer 306. The differential buffer 306 transmits a differential signal to the two distributors 310 based on the received signal. The two distributors 310 each distribute the differential signal to a plurality of second transmitting electrodes 304. The inner distributor 310 distributes the positive-phase signal to the plurality of inner second transmitting electrodes 304. The outer distributor 310 distributes the inverted-phase signal to the plurality of outer second transmitting electrodes 304.

[0036] The plurality of second transmitting electrodes 304 formed on the same second circle 308 on the rotating-side substrate 307 receive a differential signal from the differential buffer 306 via the distributor 310. Note that in the rotating-side substrate 307, the description of the differential operation is omitted because it overlaps with the description in Figure 2(a).

[0037] The rotation axis of the rotating-side substrate 307 is set to be substantially the same as the axis of the fixed-side substrate 207. The plurality of second transmitting electrodes 304 are each formed in an arc shape on the same second circle 308.

[0038] Also, the plurality of first receiving electrodes 301 formed on the same second circle 308 on the rotating-side substrate 307 transmit a differential signal to the two synthesizers 311 in the first receiving circuit 302.

[0039] The inner synthesizer 311 synthesizes the positive-phase signals of the plurality of inner first receiving electrodes 301. The outer synthesizer 311 synthesizes the inverted-phase signals of the plurality of outer first receiving electrodes 301.

[0040] Comparator circuit 309 restores the signal synthesized by synthesizer 311 from the signal generated on the first receiving electrode 301 by electric field coupling in response to the input of an electrical signal to the plurality of first receiving electrodes 301 into an electrical signal and outputs it.

[0041] Figure 2(c) is a cross-sectional view taken along line C-C' of Figures 2(a) and (b). Figure 2(d) is a cross-sectional view taken along line D-D' of Figures 2(a) and (b). As shown in Figures 2(c) and (d), the first circle 208 and the second circle 308 are set to face each other. Here, the first circle 208 is a general term for the first circles 208-1 and 208-2. Thereby, as shown in Figure 2(c), the second transmission electrode 304 and the second receiving electrode 203 are arranged to face each other. Also, as shown in Figure 2(d), the first transmission electrode 202 and the first receiving electrode 301 are arranged to face each other. Non-contact communication is realized between the first transmission electrode 202 and the plurality of first receiving electrodes 301, and between the plurality of second transmission electrodes 304 and the second receiving electrode 203.

[0042] In both Figures 2(c) and 2(d), the upper side is the rotating substrate 307 and the lower side is the fixed substrate 207. The fixed substrate 207 and the rotating substrate 307 face each other with a space therebetween, and the electrodes also face each other. On the C' side of Figure 2(c), the second receiving electrode 203 and the plurality of second transmission electrodes 304 face each other, and signals can be transmitted non-contact from the rotating substrate 307 to the fixed substrate 207.

[0043] On the other hand, on the D' side of Figure 2(d), the first transmission electrode 202 and the plurality of first receiving electrodes 301 face each other, and signals can be transmitted non-contact from the fixed substrate 207 to the rotating substrate 307. That is, two-way communication can be realized without arranging the transmission and reception electrodes in parallel.

[0044] Thereby, in the rotating non-contact communication system 100, interference can be reduced without providing a GND electrode, and improvement in communication quality and miniaturization of the communication system 100 can be realized.

[0045] When performing non-contact communication with multiple channels in single-ended mode, separate signals may be input to the inner first transmission electrode 202-1 and the outer first transmission electrode 202-2. Also in this case, since the electrodes do not run parallel between the first transmission electrode 202 and the second reception electrode 203, and between the plurality of first reception electrodes 301 and the plurality of second transmission electrodes 304, interference can be reduced without providing a GND electrode. Further, improvement in communication quality and miniaturization of the communication system 100 can be achieved.

[0046] Note that the number of electrodes can also be increased by providing a third circle 212, a third transmission electrode 213, a fourth circle 312, and a plurality of third reception electrodes 313 as shown in FIGS. 3(a) and (b) according to the number of channels, and opposing the third circle 212 and the fourth circle 312. In that case, on each of the fixed-side substrate 207 and the rotation-side substrate 307, the plurality of transmission electrodes are arranged to run parallel to each other, and the plurality of reception electrodes are arranged to run parallel to each other, thereby reducing interference between channels.

[0047] When the relative angle between the fixed-side substrate 207 and the rotation-side substrate 307 changes, the electrodes among the plurality of first reception electrodes 301 and the plurality of second transmission electrodes 304 that strongly couple with the fixed-side electrodes change. However, if the electrodes are facing each other, two-way communication can be performed.

[0048] At this time, it is desirable that the plurality of second transmission electrodes 304 and the plurality of first reception electrodes 301 be arranged to be point-symmetrical with respect to the rotation axis. By arranging the electrodes in point symmetry, the relative rotation angle at which the electrodes face each other can be increased, and the range of relative rotation angles that can achieve two-way non-contact communication is increased.

[0049] Also, for example, a case will be described where the electrode formed on the fixed-side substrate 207 has the shape shown in FIG. 4(a), and the electrode formed on the rotating-side substrate 307 has the shape shown in FIG. 4(b). In that case, since at least one of the first transmission electrode 202 and the plurality of first reception electrodes 301 always faces each other, and at least one of the plurality of second transmission electrodes 304 and the second reception electrode 203 always faces each other, non-contact communication can be realized regardless of the relative rotation angle. That is, non-contact communication can be performed without interruption even when rotating more than 360°, and it can also be applied to applications that perform two-way non-contact communication even during infinite rotation.

[0050] At this time, by increasing the distances between the first transmission electrode 202 and the second reception electrode 203, and between the plurality of first reception electrodes 301 and the plurality of second transmission electrodes 304, interference can be further reduced. However, the area where the electrodes on the fixed-side substrate 207 and the rotating-side substrate 307 can face each other decreases, and there may be a relative rotation angle at which two-way non-contact communication cannot be realized. That is, the relative rotation angle and interference are in a trade-off relationship, and it is better to adjust the arc length of the electrodes according to the application.

[0051] For example, in an application where the relative rotation angle is small, the distance between the first transmission electrode 202 and the second reception electrode 203 can be increased to further reduce interference. On the other hand, in an application where communication establishment is always required even during 360° rotation, as shown in FIG. 4(a), it is considered desirable to reduce the distance between the first transmission electrode 202 and the second reception electrode 203.

[0052] Also, as shown in FIGS. 5(a) and 5(b), the shapes of the fixed-side substrate 207 and the rotating-side substrate 307 do not have to be circular, and other shapes such as an annular shape may be used. Also, as long as the electrodes are configured to face each other, the electrodes may be configured by a copper wire, an iron pipe, etc. without using the fixed-side substrate 207 and the rotating-side substrate 307.

[0053] Also, although examples of differential non-contact transmission have been described so far, as shown in FIGS. 5(c) and (d), single-ended non-contact communication may be performed using a single electrode. That is, one first transmission electrode 202 and one second reception electrode 203 are arranged on one first circle 208 of the fixed-side substrate 207. Also, a plurality of first reception electrodes 301 and a plurality of second transmission electrodes 304 are arranged on one second circle 308 of the rotation-side substrate 307.

[0054] In this way, in the communication system 100 that performs two-way communication by electromagnetic field coupling, it is possible to reduce interference of electromagnetic field communication and realize improvement of communication quality and miniaturization of the communication system 100 without providing a shield.

[0055] [Second Embodiment] Next, the second embodiment will be described. Hereinafter, the differences between the second embodiment and the first embodiment will be described.

[0056] FIGS. 6(a) to 6(d) are diagrams showing configuration examples of the fixed-side substrate 207 and the rotation-side substrate 307 according to the second embodiment. For the sake of explanation, the regions of the fixed-side substrate 207 and the rotation-side substrate 307 are divided into four, and the communication state in a state where the quadrants face each other will be described.

[0057] First, the communication relationship when the state of the fixed-side substrate 207 is FIG. 6(a) and the state of the rotation-side substrate 307 is FIG. 6(b) will be described. Non-contact communication from the fixed-side substrate 207 to the rotation-side substrate 307 is performed by electric field coupling in the third and fourth quadrants where the first transmission electrode 202 and the plurality of first reception electrodes 301 face each other. Non-contact communication from the rotation-side substrate 307 to the fixed-side substrate 207 is performed by electric field coupling in the first and second quadrants where the plurality of second transmission electrodes 304 and the second reception electrode 203 face each other.

[0058] At this time, since the electric field coupling between the first transmission electrode 202 and the first reception electrode 301 in the first quadrant and the second quadrant is infinitely small, the influence on non-contact communication is infinitely small. On the other hand, since there is an electric field interfering from the plurality of second transmission electrodes 304, by not receiving a signal from the first reception electrode 301 in the first quadrant and the second quadrant, the influence of interference can be further reduced.

[0059] That is, by switching the electrode that receives the signal according to the coupling degree of each electrode and the relative rotation angle between the fixed-side substrate 207 and the rotating-side substrate 307, the influence of interference can be reduced and further improvement in communication quality can be achieved. For example, the electrode that receives the signal may be changed using a switch, a multiplexer, etc. according to the relative rotation angle, or it can be realized by relatively increasing the signal of the electrode with a high coupling degree using an attenuator or an amplifier.

[0060] The first reception circuit 302 does not receive a signal from the first reception electrode 301 in the first quadrant and the second quadrant, receives a signal from the first reception electrode 301 in the third quadrant and the fourth quadrant, and restores the received signal. Thereby, the influence of interference can be reduced and the communication quality can be improved.

[0061] Next, the relationship of communication will be described by taking the case where the state of the fixed-side substrate 207 is as shown in FIG. 6(c) and the state of the rotating-side substrate 307 is as shown in FIG. 6(d) as an example.

[0062] Non-contact communication from the fixed-side substrate 207 to the rotating-side substrate 307 is performed by electric field coupling in the fourth quadrant where the first transmission electrode 202 and the plurality of first reception electrodes 301 face each other. Non-contact communication from the rotating-side substrate 307 to the fixed-side substrate 207 is performed by electric field coupling in the first quadrant where the plurality of second transmission electrodes 304 and the second reception electrode 203 face each other.

[0063] At this time, since the electric field coupling between the first transmission electrode 202 and the first reception electrode 301 in the second quadrant is extremely small, the influence on non-contact communication is extremely small. On the other hand, since there is an interfering electric field from the plurality of second transmission electrodes 304, the influence of interference can be further reduced by not receiving a signal from the first reception electrode 301 in this second quadrant.

[0064] The first reception circuit 302 does not receive a signal from the first reception electrode 301 in the second quadrant, receives a signal from the first reception electrode 301 in the fourth quadrant, and restores the received signal. Thereby, the influence of interference can be reduced and the communication quality can be improved.

[0065] Also, since the electric field coupling between the second transmission electrode 304 and the second reception electrode 203 in the third quadrant is extremely small, the influence on non-contact communication is extremely small. By not transmitting a signal from the second transmission electrode 304 in this third quadrant, the influence of interference can be further reduced.

[0066] That is, by switching the electrode for transmitting a signal according to the coupling degree of each electrode and the relative rotation angle between the fixed-side substrate 207 and the rotating-side substrate 307, the influence of interference can be reduced and further improvement in communication quality can be achieved. For example, the electrode for transmitting a signal may be changed using a switch, a multiplexer, etc. according to the relative rotation angle, or it can be realized by relatively increasing the signal of the electrode with a high coupling degree using an attenuator or an amplifier.

[0067] The second transmission circuit 303 does not transmit a signal to the second transmission electrode 304 in the third quadrant, and transmits a signal to the second transmission electrode 304 in the first quadrant. Thereby, the influence of interference can be reduced and the communication quality can be improved.

[0068] In this way, by controlling the signals input to and output from the electrodes according to the relative rotation angle between the fixed-side substrate 207 and the rotating-side substrate 307, the influence of interference can be reduced and further improvement in communication quality can be achieved.

[0069] As described above, the communication system 100 in FIG. 1 includes a first communication device 200 and a second communication device 300. In FIG. 2(a), the first communication device 200 has an arc-shaped first transmission electrode 202-1 disposed on the circumference of the first circle 208-1 and an arc-shaped second reception electrode 203-1 disposed on the circumference of the first circle 208-1.

[0070] In FIG. 2(b), the second communication device 300 has a plurality of arc-shaped first reception electrodes 301-1 disposed on the circumference of the second circle 308-1 and a plurality of arc-shaped second transmission electrodes 304-1 disposed on the circumference of the second circle 308-1. Here, the second circle 308-1 is the inner second circle 308 of the two second circles 308. The plurality of first reception electrodes 301-1 are the inner plurality of first reception electrodes 301. The plurality of second transmission electrodes 304-1 are the inner plurality of second transmission electrodes 304.

[0071] As shown in FIGS. 2(a) to 2(d), the first communication device 200 and the second communication device 300 are relatively rotatable with respect to each other about a line connecting the center point of the first circle 208-1 and the center point of the second circle 308-1 as a rotation axis.

[0072] The first transmission electrode 202 and at least one first reception electrode among the plurality of first reception electrodes 301-1 are arranged to face each other to perform non-contact communication. Also, at least one second transmission electrode among the plurality of second transmission electrodes 304-1 and the second reception electrode 203-1 are arranged to face each other to perform non-contact communication.

[0073] The radius of the first circle 208-1 and the radius of the second circle 308-1 are substantially the same as each other. The first communication device 200 and the second communication device 300 are relatively rotatable 360° with respect to each other.

[0074] In FIG. 4(b), the sum of the average value of the arc lengths of the plurality of first reception electrodes 301 and the average value of the arc lengths of the plurality of second transmission electrodes 304 is approximately 1 / 2 of the circumference length of the second circle 308.

[0075] In Fig. 3(a), the first communication device 200 further has an arc-shaped third transmission electrode 213 disposed on the circumference of the third circle 212. The third transmission electrode 213 runs parallel to the first transmission electrode 202. The first circle 208 and the third circle 212 have substantially the same center point and different radii from each other.

[0076] In Fig. 3(b), the second communication device 300 further has a plurality of arc-shaped third reception electrodes 313 disposed on the circumference of the fourth circle 312. The plurality of third reception electrodes 313 run parallel to the plurality of first reception electrodes 301. The second circle 308 and the fourth circle 312 have substantially the same center point and different radii from each other.

[0077] The radius of the third circle 212 and the radius of the fourth circle 312 are substantially the same as each other. The third transmission electrode 213 and at least one of the plurality of third reception electrodes 313 are arranged to face each other to perform non-contact communication.

[0078] In Fig. 3(c), the first communication device 200 further has an arc-shaped fourth reception electrode 214 disposed on the circumference of the third circle 212. The fourth reception electrode 214 runs parallel to the second reception electrode 203. The first circle 208 and the third circle 212 have substantially the same center point and different radii from each other.

[0079] In Fig. 3(d), the second communication device 300 further has a plurality of arc-shaped fourth transmission electrodes 314 disposed on the circumference of the fourth circle 312. The plurality of fourth transmission electrodes 314 run parallel to the plurality of second transmission electrodes 304. The second circle 308 and the fourth circle 312 have substantially the same center point and different radii from each other.

[0080] The radius of the third circle 212 and the radius of the fourth circle 312 are substantially the same as each other. At least one of the plurality of fourth transmission electrodes 314 and the fourth reception electrode 214 are arranged to face each other to perform non-contact communication.

[0081] Note that the communication system 100 may combine the configurations of Figs. 3(a) and (b) with the configurations of Figs. 3(c) and (d).

[0082] In FIGS. 2(a) to 2(d), the first transmission electrodes 202-1 and 202-2, the plurality of first reception electrodes 301, the plurality of second transmission electrodes 304, and the second reception electrodes 203-1 and 203-2 are respectively differential pair electrodes.

[0083] In FIG. 2(a), the first communication device 200 further includes a first differential buffer 206 that transmits a differential signal to the first transmission electrode 202. The first communication device 200 further includes a comparator circuit (first restoration unit) 209 that restores the signals of the second reception electrodes 203-1 and 203-2. The comparator circuit 209 inputs the signals of the differential pair of second reception electrodes 203-1 and 203-2.

[0084] In FIG. 2(b), the second communication device 300 further includes a second differential buffer 306 that transmits a differential signal to the distributor 310, and a distributor 310 that distributes the signal to the plurality of second transmission electrodes 304. The second communication device 300 further includes a synthesizer 311 that synthesizes the signals of the plurality of first reception electrodes 301, and a comparator circuit (second restoration unit) 309 that restores the signal synthesized by the synthesizer 311. The comparator circuit 309 inputs the signals of the differential pair of first reception electrodes 301.

[0085] The plurality of first reception electrodes 301 are arranged to be point-symmetrical with respect to the above rotation axis. The plurality of second transmission electrodes 304 are arranged to be point-symmetrical with respect to the above rotation axis.

[0086] In FIG. 1, the communication system 100 further includes a rotation control unit 101 that controls the first communication device 200 and the second communication device 300 to rotate relative to each other.

[0087] In FIGS. 6(a) to 6(d), the first reception circuit 302 selects, attenuates, or amplifies the signal received from any one of the plurality of first reception electrodes 301 according to the relative rotation angle between the first communication device 200 and the second communication device 300.

[0088] Further, the first receiving circuit 302 may select, attenuate, or amplify a signal received from any one of the plurality of first receiving electrodes 301 according to the degree of coupling of an electric field, a magnetic field, or both an electric field and a magnetic field between the first transmitting electrode 202 and at least one of the plurality of first receiving electrodes.

[0089] Also, in FIGS. 6(c) and 6(d), the second transmitting circuit 303 selects, attenuates, or amplifies a signal to be transmitted to any one of the plurality of second transmitting electrodes 304 according to the relative rotation angle between the first communication device 200 and the second communication device 300.

[0090] Further, the second transmitting circuit 303 may select, attenuate, or amplify a signal to be transmitted to any one of the plurality of second transmitting electrodes 304 according to the degree of coupling of an electric field, a magnetic field, or both an electric field and a magnetic field between at least one of the plurality of second transmitting electrodes 304 and the second receiving electrode 203.

[0091] In FIG. 6(a), the first transmitting electrode 202 is not disposed in the first and second quadrants of the first circle 208 and the second circle 308, but is disposed in the third and fourth quadrants of the first circle 208 and the second circle 308. In FIG. 6(b), the second communication device 300 includes the first receiving electrodes 301 disposed in the first and second quadrants and the first receiving electrodes 301 disposed in the third and fourth quadrants. The first receiving circuit 302 does not receive the signals of the first receiving electrodes 301 disposed in the first and second quadrants, but receives the signals of the first receiving electrodes 301 disposed in the third and fourth quadrants.

[0092] In FIG. 6(c), the first transmitting electrode 202 is not disposed in the first and second quadrants of the first circle 208 and the second circle 308, but is disposed in the third and fourth quadrants of the first circle 208 and the second circle 308. In FIG. 6(d), the second communication device 300 includes the first receiving electrodes 301 disposed in the second quadrant and the first receiving electrodes 301 disposed in the fourth quadrant. The first receiving circuit 302 does not receive the signals of the first receiving electrodes 301 disposed in the second quadrant, but receives the signals of the first receiving electrodes 301 disposed in the fourth quadrant.

[0093] In FIG. 6(c), the second receiving electrode 203 is disposed in the first and second quadrants of the first circle 208 and the second circle 308, and is not disposed in the third and fourth quadrants of the first circle 208 and the second circle 308. In FIG. 6(d), the second communication device 300 includes the second transmitting electrode 304 disposed in the first quadrant described above and the second transmitting electrode 304 disposed in the third quadrant described above. The second transmitting circuit 303 does not transmit a signal to the second transmitting electrode 304 disposed in the third quadrant, and transmits a signal to the second transmitting electrode 304 disposed in the first quadrant.

[0094] As described above, according to the first and second embodiments, the communication system 100 is a communication system that performs two-way communication by electromagnetic field coupling, and can reduce the interference of electromagnetic field communication and realize an improvement in communication quality and miniaturization of the communication system without providing a shield.

[0095] Note that each of the above-described embodiments is merely a specific example for implementing the present disclosure, and the technical scope of the present disclosure is not limitedly interpreted by these. That is, the present disclosure can be implemented in various forms without departing from its technical idea or its main features.

[0096] The disclosure of the present embodiment includes the following configurations. (Configuration 1) A first communication device, And a second communication device, The first communication device An arc-shaped first transmitting electrode disposed on the circumference of a first circle, And an arc-shaped second receiving electrode disposed on the circumference of the first circle, The second communication device A plurality of arc-shaped first receiving electrodes disposed on the circumference of a second circle, And a plurality of arc-shaped second transmitting electrodes disposed on the circumference of the second circle, The first communication device and the second communication device are relatively rotatable with respect to each other about a line connecting the center point of the first circle and the center point of the second circle as a rotation axis, The first transmission electrode and at least one first reception electrode among the plurality of first reception electrodes are arranged to face each other to perform non-contact communication. A communication system, wherein at least one second transmission electrode among the plurality of second transmission electrodes and the second reception electrode are arranged to face each other to perform non-contact communication. (Configuration 2) The communication system according to Configuration 1, wherein the radius of the first circle and the radius of the second circle are substantially the same as each other. (Configuration 3) The communication system according to Configuration 1 or 2, wherein the first communication device and the second communication device are rotatable relative to each other by 360°. (Configuration 4) The communication system according to any one of Configurations 1 to 3, wherein the sum of the average value of the arc lengths of the plurality of first reception electrodes and the average value of the arc lengths of the plurality of second transmission electrodes is approximately 1 / 2 of the circumference length of the second circle. (Configuration 5) The first communication device further has an arc-shaped third transmission electrode disposed on the circumference of a third circle. The second communication device further has a plurality of arc-shaped third reception electrodes disposed on the circumference of a fourth circle. The third transmission electrode runs parallel to the first transmission electrode. The plurality of third reception electrodes run parallel to the plurality of first reception electrodes. The first circle and the third circle have substantially the same center point and different radii from each other. The second circle and the fourth circle have substantially the same center point and different radii from each other. The communication system according to any one of Configurations 1 to 4, wherein the third transmission electrode and at least one third reception electrode among the plurality of third reception electrodes are arranged to face each other to perform non-contact communication. (Configuration 6) The communication system according to Configuration 5, wherein the radius of the third circle and the radius of the fourth circle are substantially the same as each other. (Configuration 7) The first communication device further includes an arc-shaped fourth receiving electrode disposed on the circumference of a third circle. The second communication device further includes a plurality of arc-shaped fourth transmitting electrodes disposed on the circumference of a fourth circle. The fourth receiving electrode runs parallel to the second receiving electrode. The plurality of fourth transmitting electrodes run parallel to the plurality of second transmitting electrodes. The first circle and the third circle have substantially the same center point and different radii from each other. The second circle and the fourth circle have substantially the same center point and different radii from each other. A communication system according to any one of Configurations 1 to 6, wherein at least one of the plurality of fourth transmitting electrodes and the fourth receiving electrode are arranged to face each other to perform non-contact communication. (Configuration 8) A communication system according to Configuration 7, wherein the radius of the third circle and the radius of the fourth circle are substantially the same as each other. (Configuration 9) A communication system according to any one of Configurations 1 to 8, wherein the first transmitting electrode, the plurality of first receiving electrodes, the plurality of second transmitting electrodes, and the second receiving electrode are each an electrode of a differential pair. (Configuration 10) A communication system according to any one of Configurations 1 to 9, wherein the second communication device further includes a synthesizer that synthesizes signals of the plurality of first receiving electrodes. (Configuration 11) The first communication device further includes a first restoration unit that restores the signal of the second receiving electrode. A communication system according to Configuration 10, wherein the second communication device further includes a second restoration unit that restores the signal synthesized by the synthesizer. (Configuration 12) The first transmitting electrode, the plurality of first receiving electrodes, the plurality of second transmitting electrodes, and the second receiving electrode are each an electrode of a differential pair, The communication system according to Configuration 11, wherein the first restoration unit and the second restoration unit are each a comparator circuit that inputs signals of electrodes of a differential pair. (Configuration 13) The communication system according to any one of Configurations 1 to 12, wherein the second communication device further includes a distributor that distributes signals to the plurality of second transmission electrodes. (Configuration 14) The first transmission electrode, the plurality of first reception electrodes, the plurality of second transmission electrodes, and the second reception electrode are each an electrode of a differential pair, The first communication device further includes a first differential buffer that transmits a differential signal to the first transmission electrode, The communication system according to Configuration 13, wherein the second communication device further includes a second differential buffer that transmits a differential signal to the distributor. (Configuration 15) The communication system according to any one of Configurations 1 to 14, wherein the plurality of first reception electrodes are arranged to be point-symmetrical with respect to the rotation axis. (Configuration 16) The communication system according to any one of Configurations 1 to 15, wherein the plurality of second transmission electrodes are arranged to be point-symmetrical with respect to the rotation axis. (Configuration 17) The communication system according to any one of Configurations 1 to 16, further including a rotation control unit that controls the first communication device and the second communication device to rotate relative to each other. (Configuration 18) The communication system according to any one of Configurations 1 to 17, wherein the second communication device further includes a first reception circuit that selects, attenuates, or amplifies a signal received from any one of the plurality of first reception electrodes according to a relative rotation angle between the first communication device and the second communication device. (Configuration 19) The second communication device further includes a second transmission circuit that selects, attenuates, or amplifies a signal to be transmitted to any one of the plurality of second transmission electrodes according to a relative rotation angle between the first communication device and the second communication device. The communication system according to any one of Configurations 1 to 18. (Configuration 20) The second communication device further includes a first reception circuit that selects, attenuates, or amplifies a signal received from any one of the plurality of first reception electrodes according to a coupling degree of an electric field, a magnetic field, or both an electric field and a magnetic field between the first transmission electrode and at least one of the plurality of first reception electrodes. The communication system according to any one of Configurations 1 to 17. (Configuration 21) The second communication device further includes a second transmission circuit that selects, attenuates, or amplifies a signal to be transmitted to any one of the plurality of second transmission electrodes according to a coupling degree of an electric field, a magnetic field, or both an electric field and a magnetic field between at least one of the plurality of second transmission electrodes and the second reception electrode. The communication system according to any one of Configurations 1 to 17, 20. (Configuration 22) The first transmission electrode is not disposed in the first and second quadrants of the first circle and the second circle, but is disposed in the third and fourth quadrants of the first circle and the second circle. The plurality of first reception electrodes include first reception electrodes disposed in the first and second quadrants and first reception electrodes disposed in the third and fourth quadrants. The second communication device further includes a first reception circuit that does not receive signals from the first reception electrodes disposed in the first and second quadrants, but receives signals from the first reception electrodes disposed in the third and fourth quadrants. The communication system according to any one of Configurations 1 to 17. (Configuration 23) The first transmission electrode is not disposed in the first and second quadrants of the first circle and the second circle, but is disposed in the third and fourth quadrants of the first circle and the second circle. The plurality of first reception electrodes include first reception electrodes disposed in the second quadrant and first reception electrodes disposed in the fourth quadrant. The second communication device further includes a first receiving circuit that does not receive the signal of the first receiving electrode disposed in the second quadrant and receives the signal of the first receiving electrode disposed in the fourth quadrant, according to any one of Configurations 1 to 17 of the communication system. (Configuration 24) The second receiving electrode is disposed in the first and second quadrants of the first circle and the second circle, and not in the third and fourth quadrants of the first circle and the second circle. The plurality of second transmitting electrodes includes a second transmitting electrode disposed in the first quadrant and a second transmitting electrode disposed in the third quadrant. The second communication device further includes a second transmitting circuit that does not transmit a signal to the second transmitting electrode disposed in the third quadrant and transmits a signal to the second transmitting electrode disposed in the first quadrant, according to any one of Configurations 1 to 17, 23 of the communication system.

Explanation of Reference Numerals

[0097] 100 Communication system, 101 Rotation control unit, 200 Fixed-side communication device, 201 First transmitting circuit, 202 First transmitting electrode, 202-1 Inner first transmitting electrode, 202-2 Outer first transmitting electrode, 203 Second receiving electrode, 203-1 Inner second receiving electrode, 203-2 Outer second receiving electrode, 204 Second receiving circuit, 207 Fixed-side substrate, 208 First circle, 208-1 Inner first circle, 208-2 Outer first circle, 212 Third circle, 213 Third transmitting electrode, 300 Rotating-side communication device, 301 Plurality of first receiving electrodes, 302 First receiving circuit, 303 Second transmitting circuit, 304 Plurality of second transmitting electrodes, 307 Rotating-side substrate, 308 Second circle, 310 Distributor, 311 Combiner, 312 Fourth circle, 313 Plurality of third receiving electrodes, 205, 305 Signal source, 206, 306 Differential buffer, 209, 309 Comparator circuit

Claims

1. A first communication device and a second communication device, wherein the first communication device has an arcuate first transmission electrode disposed on the circumference of a first circle, and an arcuate second reception electrode disposed on the circumference of the first circle, the second communication device has a plurality of arcuate first reception electrodes disposed on the circumference of a second circle, and a plurality of arcuate second transmission electrodes disposed on the circumference of the second circle, the first communication device and the second communication device are relatively rotatable about a line connecting the center point of the first circle and the center point of the second circle as a rotation axis, the first transmission electrode and at least one of the plurality of first reception electrodes are arranged to face each other to perform non-contact communication, and at least one of the plurality of second transmission electrodes and the second reception electrode are arranged to face each other to perform non-contact communication. A communication system characterized by this.

2. The communication system according to claim 1, wherein the radius of the first circle and the radius of the second circle are substantially the same as each other.

3. The communication system according to claim 1, wherein the first communication device and the second communication device are relatively rotatable 360°.

4. The communication system according to claim 1, wherein the sum of the average value of the arc lengths of the plurality of first reception electrodes and the average value of the arc lengths of the plurality of second transmission electrodes is approximately 1 / 2 of the circumference length of the second circle.

5. The first communication device further has an arcuate third transmission electrode disposed on the circumference of a third circle, the second communication device further has a plurality of arcuate third reception electrodes disposed on the circumference of a fourth circle, the third transmission electrode runs parallel to the first transmission electrode, the plurality of third reception electrodes run parallel to the plurality of first reception electrodes, the first circle and the third circle have substantially the same center point and different radii from each other, the second circle and the fourth circle have substantially the same center point and different radii from each other, and the third transmission electrode and at least one of the plurality of third reception electrodes are arranged to face each other to perform non-contact communication. The communication system according to claim 1 is characterized by this.

6. The communication system according to claim 5, wherein the radius of the third circle and the radius of the fourth circle are substantially the same as each other.

7. The first communication device further has an arcuate fourth reception electrode disposed on the circumference of a third circle, The second communication device further includes a plurality of arc-shaped fourth transmission electrodes arranged on the circumference of a fourth circle. The fourth receiving electrode runs parallel to the second receiving electrode. The plurality of fourth transmission electrodes run parallel to the plurality of second transmission electrodes. The first circle and the third circle have substantially the same center point and different radii from each other. The second circle and the fourth circle have substantially the same center point and different radii from each other. The communication system according to claim 1, wherein at least one of the plurality of fourth transmission electrodes and the fourth receiving electrode are arranged to face each other to perform non-contact communication.

8. The communication system according to claim 7, wherein the radius of the third circle and the radius of the fourth circle are substantially the same as each other.

9. The communication system according to claim 1, wherein the first transmission electrode, the plurality of first receiving electrodes, the plurality of second transmission electrodes, and the second receiving electrode are each an electrode of a differential pair.

10. The communication system according to claim 1, wherein the second communication device further includes a synthesizer for synthesizing signals of the plurality of first receiving electrodes.

11. The first communication device further includes a first restoration unit for restoring the signal of the second receiving electrode. The communication system according to claim 10, wherein the second communication device further includes a second restoration unit for restoring the signal synthesized by the synthesizer.

12. The first transmission electrode, the plurality of first receiving electrodes, the plurality of second transmission electrodes, and the second receiving electrode are each an electrode of a differential pair. The communication system according to claim 11, wherein the first restoration unit and the second restoration unit are each a comparator circuit for inputting signals of electrodes of a differential pair.

13. The communication system according to claim 1, wherein the second communication device further includes a distributor for distributing signals to the plurality of second transmission electrodes.

14. The first transmission electrode, the plurality of first receiving electrodes, the plurality of second transmission electrodes, and the second receiving electrode are each an electrode of a differential pair. The first communication device further includes a first differential buffer for transmitting a differential signal to the first transmission electrode. The communication system according to claim 13, wherein the second communication device further includes a second differential buffer for transmitting a differential signal to the distributor.

15. The communication system according to claim 1, wherein the plurality of first receiving electrodes are arranged to be point-symmetric with respect to the rotation axis.

16. The communication system according to claim 1, wherein the plurality of second transmitting electrodes are arranged to be point-symmetric with respect to the rotation axis.

17. The communication system according to claim 1, further comprising a rotation control unit that controls the first communication device and the second communication device to rotate relative to each other.

18. The second communication device further comprises a first receiving circuit that selects, attenuates, or amplifies a signal received from any one of the plurality of first receiving electrodes according to a relative rotation angle between the first communication device and the second communication device. The communication system according to claim 1 is characterized by this.

19. The second communication device further comprises a second transmitting circuit that selects, attenuates, or amplifies a signal to be transmitted to any one of the plurality of second transmitting electrodes according to a relative rotation angle between the first communication device and the second communication device. The communication system according to claim 1 is characterized by this.

20. The second communication device further comprises a first receiving circuit that selects, attenuates, or amplifies a signal received from any one of the plurality of first receiving electrodes according to the degree of coupling of an electric field, a magnetic field, or both an electric field and a magnetic field between the first transmitting electrode and at least one of the plurality of first receiving electrodes. The communication system according to claim 1 is characterized by this.

21. The second communication device further comprises a second transmitting circuit that selects, attenuates, or amplifies a signal to be transmitted to any one of the plurality of second transmitting electrodes according to the degree of coupling of an electric field, a magnetic field, or both an electric field and a magnetic field between at least one of the plurality of second transmitting electrodes and the second receiving electrode. The communication system according to claim 1 is characterized by this.

22. The first transmitting electrode is not arranged in the first and second quadrants of the first circle and the second circle, but is arranged in the third and fourth quadrants of the first circle and the second circle. The plurality of first receiving electrodes include first receiving electrodes arranged in the first and second quadrants and first receiving electrodes arranged in the third and fourth quadrants. The second communication device further includes a first receiving circuit that does not receive signals from the first receiving electrodes disposed in the first quadrant and the second quadrant, but receives signals from the first receiving electrodes disposed in the third quadrant and the fourth quadrant. The communication system according to claim 1, characterized in that.

23. The first transmission electrode is not disposed in the first quadrant and the second quadrant of the first circle and the second circle, but is disposed in the third quadrant and the fourth quadrant of the first circle and the second circle. The plurality of first receiving electrodes include a first receiving electrode disposed in the second quadrant and a first receiving electrode disposed in the fourth quadrant. The second communication device further includes a first receiving circuit that does not receive signals from the first receiving electrodes disposed in the second quadrant, but receives signals from the first receiving electrodes disposed in the fourth quadrant. The communication system according to claim 1, characterized in that.

24. The second receiving electrode is disposed in the first quadrant and the second quadrant of the first circle and the second circle, and is not disposed in the third quadrant and the fourth quadrant of the first circle and the second circle. The plurality of second transmission electrodes include a second transmission electrode disposed in the first quadrant and a second transmission electrode disposed in the third quadrant. The second communication device further includes a second transmission circuit that does not transmit a signal to the second transmission electrode disposed in the third quadrant, but transmits a signal to the second transmission electrode disposed in the first quadrant. The communication system according to claim 1, characterized in that.

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