DEVICE HOUSING FOR WIRELESSLY RECEIVING POWER, AND DEVICE HAVING THE SAME

A device housing is provided for wirelessly receiving electric power in order to supply electric power to a device with an excellent power-receiving efficiency, while suppressing an increase in its size as a whole. Also, a device having the same device housing and a device housing for constituting a main body of a device which is a sensor or an actuator are provided. The device housing is provided with a power-receiving device for mainly generating an electric field or a magnetic field for performing wireless power supply. The power-receiving device includes at least one of a dipole antenna, a slot antenna, a monopole antenna, a chip antenna and an inverted-F antenna. The device housing has a size in a three-dimensional space, and expansion of its size in the three-dimensional space due to the provision of the power-receiving devices is substantially limited to one axis direction (X-axis direction) at most.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-194699, entitled “WIRELESS POWER SUPPLY DEVICE,” filed on Nov. 24, 2020, and the content of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a device housing for wirelessly receiving electric power, and a device having the same device housing.

BACKGROUND

Various sensors and actuators may be used in the fields of plants (FA: Factory Automation), Internet of things (IoT), and home electric appliances, etc. In general, in sensors and actuators, a wiring for a power source is not made wirelessly.

For example, for performing wireless power supply to a proximity sensor, it is conceivable that a power-receiving device such as an antenna is provided by combining with the proximity sensor. However, when energy is received wirelessly, there are problems such as a decrease in power-receiving efficiency comparing with a case of performing wired power supply. In addition, when a proximity sensor is provided with an antenna or the like, there are problems such as an increase in a size of the proximity sensor, as a whole.

With respect to the background art on this technical field, there is JP2014-7629A (which is hereinafter referred as Patent Document 1). In the Patent Document 1, it is disclosed that “a proximity sensor10is configured to include a first antenna1, a second antenna2and a unit for detecting voltage standing wave ratio3. In the second antenna2, the change direction of the resonance frequency with regard to changes of the distance to an object is reverse to the direction of the resonance frequency of the first antenna1. In addition, the unit for detecting voltage standing wave ratio3is configured to detect first voltage standing wave ratio S1on a signal line connected to the first antenna1, and second voltage standing wave ratio S2on a signal line connected to the second antenna2(see summary)”.

In the Patent Document 1, two different kinds of antennas are provided in a proximity sensor. Especially, a loop antenna1and a helical antenna2are provided. However, according to the disclosure, the loop antenna1and the helical antenna2are not provided for receiving energy required for operating the proximity sensor. In addition, the loop antenna1and the helical antenna2may remarkably increase the size of the proximity sensor as a whole (seeFIGS.1,6). Accordingly, it is conceivable that the usability of the proximity sensor may be degraded.

PRIOR ART DOCUMENTS

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

Accordingly, it is an object of the present disclosure to provide a device housing for wirelessly receiving electric power in order to supply the electric power to a device with an excellent power-receiving efficiency, while suppressing an increase in a size of the device as a whole; and a device having the same device housing.

Means for Solving the Problem

To solve the above-mentioned problems, for example, the configuration described in the claims is applied. The present disclosure includes a plurality of means for solving the above-mentioned problems, and an example is given below.

A device housing constituting a main body of a device which is a sensor or an actuator is provided. The device housing is provided with a power-receiving device for mainly generating an electric field or a magnetic field for performing wireless power supply. The power-receiving device includes at least one of a dipole antenna, a slot antenna, a monopole antenna, a chip antenna and an inverted-F antenna. In addition, the device housing has a size in a three-dimensional space, and expansion of the size of the device housing in the three-dimensional space due to the provision of the power receiving devices is substantially limited to one axis direction at most.

Effect of the Invention

According to the present disclosure, it becomes possible to provide a device housing for wirelessly receiving electric power in order to supply the electric power to a device with an excellent power-receiving efficiency, while suppressing an increase in a size of the device as a whole; and a device having the same device housing.

Problems, configurations, and effects except those mentioned above will be clarified by referring to the description of the following embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments for carrying out the invention will be explained by referring to figures. Each one of the below-mentioned embodiments is given as an example for providing the invention. The contents of the invention will not be limited by the descriptions of the examples.

With referring toFIG.1(A), a power-receiving system1according to the present example will be explained.

The power-receiving system1is configured to include, at least, a power-receiving device20and a device (or an electric device)30. The power-receiving device20is capable of wirelessly receiving energy E transmitted from a power-transmitting device10(without using a wiring) and supplying the electric power to the device30. Accordingly, it completely removes the need for physically providing a wire (or a cable) for supplying electric power from the power-transmitting device10to the power-receiving device20.

In addition, the power-receiving device20is integrally constituted with the device30to which power is supplied. Accordingly, it removes the need for physically providing a wire (or a cable) for supplying electric power from the power-receiving device20to the device30.

As illustrated inFIG.1(B), the power-receiving system1is capable of including other elements30,40.

The power-receiving device20is defined as a device which is capable of receiving energy E wirelessly transmitted thereto, in order to supply electric power to the device30.

The power-transmitting device10which is provided in a pair with the power-receiving device20is defined as a device which is capable of wirelessly transmitting energy E.

The device30is an electric device (or a module) which is capable of being supplied with electric power as energy for operating the device30from the power-receiving device20. Especially, the device30is a sensor or an actuator.

The sensor is defined as an electric device which is capable of measuring physical quantities and of generating measured results.

The actuator is defined as an electric device which is capable of changing physical quantities based on inputted signals.

For example, the sensor30may be any one of a proximity sensor, a MR (Magnetic Resistance) sensor, a hall element, a displacement sensor, an inspection sensor, a discrimination sensor, a measuring sensor, a length measuring sensor, a vibration sensor, a microphoto sensor, a pressure sensor, a flow sensor, a temperature-humidity sensor, a human detecting sensor, a wear sensor, an acceleration sensor, a strain sensor (or distortion sensor), a force sensor, a CMOS sensor, a photoelectric sensor, a laser sensor, an ultrasonic sensor, a touch sensor, a linear cage, a potentiometer (or position sensor), an image sensor, a color sensor, a LiDAR sensor, a TOF sensor, a seismic sensor, a gyroscopic sensor, an inclination sensor, a rotation sensor, an angle sensor, a tachometer, a load cell, a false sensor, a torque sensor, a liquid level sensor, a liquid leakage/water detection sensor, a non-contact temperature sensor, a current sensor, an electric power sensor, an electrostatic sensor, and an isolator, etc.

For example, the actuator may be any one of an electric actuator, a hydraulic actuator, a pneumatic actuator (or an air pressure type actuator), a chemical actuator, a magnetic fluid actuator, and an electroviscous fluid actuator, etc.

The power-receiving system1which includes, at least, the power-receiving device20and the device30is capable of being provided in various application examples. For example, the power-receiving system1is capable of being provided in the fields of FA (such as a factory), IoT (Internet of Things), or home electric appliances, etc.

In the example illustrated inFIG.1(A), the power-receiving system1is provided in a machine100which may be an industrial robot (for example, a machine tool) or a domestic robot (for example, a home electric appliance), etc.

The machine100is capable of being configured to be used in a variety of applications, such as grasping, picking, placing, assembling, painting, or welding, etc., of a workpiece (or a component) W. Preferably, the machine100is an articulated robot which is capable of performing various operations at a high degree of freedom.

The power-receiving system1is capable of being provided in various application examples, in addition to the illustrated machine100. For example, in general, the power-receiving system1is capable of being provided so as to supply electric power to an arbitrarily sensor (for example, a proximity sensor, a magnetic sensor, or the like) for detecting objects on a line in a factory, in the FA equipment. Furthermore, in general, the power-receiving system1is capable of being provided so as to monitor conditions in an office environment (for example, with a temperature and humidity sensor, or an illumination sensor, etc.) in a building management system.

Hereinafter, the power-receiving system1provided in the articulated robot100will be explained.

In general, the articulated robot100includes a plurality of (at least two) shafts and/or joints J1a, J1b, J2a, J2b, and J2cfor operating a robot arm unit110and/or a robot hand unit120at a high degree of freedom. In general, as the number of the joints J1a, J1b, J2a, J2b, and J2cbecomes larger, the degree of freedom of the articulated robot100becomes higher, but more precise control will be required accordingly. On the other hand, as the number of the joints J1a, J1b, J2a, J2b, and J2cbecomes smaller, the mechanism of the articulated robot100becomes simpler, and a malfunction thereof will be less likely to occur.

With referring toFIG.2(C), a wiring condition of a sensor30according to the prior art is exemplified. As illustrated in the figure, in a case where a wire is provided inside the machine100in order to supply electric power to the sensor30, there are several problems. For example, when the joints J1a, J1b, J2a, J2b, and J2cof the articulated robot100are operated, loads may be applied to the wire (seeFIG.2). Accordingly, there is a risk that the wire may be broken. Furthermore, performing maintenance of the wire will be required. In addition, in a machine (for example, the articulated robot100) which is capable of performing various operations at a high degree of freedom, various components such as actuators or the like are already provided therein. Therefore, there is a problem that a size of a space for installing a wire is limited. In addition, there is a risk that the wire may be broken by being corroded by an oil or the like.

The present example is constituted to prevent the occurrence of the above-mentioned problems of wiring.

The power-receiving system1is capable of being provided in various machines100in an arbitrary manner. For example, all of the parts of the power-receiving system1may not be accommodated in a finger of the robot hand unit120illustrated inFIG.1(A). For example, a relatively large bulky part may be constituted to be flexible to be waded up for being put in a space of the finger. Also, it is possible to provide a part of the power-receiving system1at a location distant from the finger (for example, at a root of the finger of the robot hand unit120, or at a wider place in the vicinity). Further, it is possible to provide a part of the power-receiving system1so as to protrude to the outside of the machine100, as needed.

With referring toFIG.1(A), it is exemplified that the power-transmitting device10is provided to the outside of the articulated robot100at an appropriate place. The power-transmitting device10is capable of wirelessly transmitting energy E to the power-receiving device20via a power-transmitting antenna12. There are several types for wirelessly transmitting electric power. Preferably, the present example is configured to perform wireless power supply between the power-transmitting device10and the power-receiving device20based on the microwave system. According to the microwave system, it is possible to transmit energy E (or electric power) at a relatively long distance.

Hereinafter, as an example of the device30, a proximity sensor will be explained.

With referring toFIG.2(A), (B), a perspective view and a side view of a conventional proximity sensor30are illustrated.

The proximity sensor30is a device for detecting an object (as a detection target) without contacting with the object. Various types of proximity sensors30are known. For example, one type of the proximity sensors is configured to react with a metal when the metal approaches thereto. Therefore, it may not be deteriorated by abrasion with an object because the measurement is made without contacting with the object. Additionally, it has water-proofness and dust-proofness, and also it has the advantage of hardly broken. Especially, in a case of the proximity sensor which is capable of reacting with a metal, it has the advantage that it is less susceptible to dust or water drops. Further, it may have less erroneous detection. There are various types of detection distances of the proximity sensor30. For example, one type of the proximity sensors may detect an object on the mm unit. For example, the proximity sensor may be any one of an induction type proximity sensor, an electrostatic capacity type proximity sensor, and a magnetic proximity sensor.

In a case that the proximity sensor is an induction type proximity sensor, an object to be detected will be a metal conductor (in general, the metal is composed of an iron, an aluminum, a brass, or a copper, etc.). According to the principle, a magnetic loss due to an eddy current generated on a surface of a conductor is detected by influence of external magnetic fields. For example, alternating current magnetic fields are generated at a detection coil, and then a variation of impedance due to the eddy current generated on the metal body (which becomes the detection target) is detected.

In a case of an electrostatic capacity type proximity sensor, an object to be detected will be any one of a metal, a resin, a liquid, and a powder, etc. (based on the dielectric constant). According to the principle, a variation of an electrostatic capacity generated between the sensor and the detection target is detected. For example, when a metal or a dielectric approaches thereto, an electrostatic capacity between a ground potential and an electrode inside the sensor increases by an electrostatic induction effect. The oscillation amplitude increases according to a variation of the electrostatic capacity of the electrode, and then the approach of the detection target is detected.

In a case of a magnetic proximity sensor, an object to be detected will be mainly a magnet. According to the principle, a lead piece of a switch is operated by a magnet. For example, the switch is configured to be turned on by turning on the lead switch.

With referring toFIG.2(A), an example of the induction type proximity sensor30is illustrated. In this sensor30, a detection coil, an oscillation circuit, a circuit for detecting an oscillation condition, and an output circuit (which are not illustrated in the figure) may be accommodated in a device housing (for example, a housing or a case) which is configured to constitute a main body of the sensor30. A detection surface32is provided at one end of the device housing31, and the detection surface32is capable of emitting high-frequency magnetic fields from the detection coil according to the oscillation circuit. When a metal object (see reference symbol W inFIG.1) approaches in the high-frequency magnetic fields, an induction current flows in the approaching metal due to an electromagnetic induction phenomenon. Accordingly, a heat loss is generated in the metal object W. When this condition occurs, the circuit for detecting the oscillation condition detects an attenuation or a stop of the oscillation, and then the result is outputted by the output circuit to the outside.

The proximity sensor30is required to be supplied with electric power in order to perform the above-mentioned detection operations and to generate electric signals. Usually, in the conventional proximity sensor30, a connector for wiring (or an attaching member)33is provided at one end side of the device housing31opposite to the detection surface32. In general, the connector33is made of metal, and a wire (or a cable) for receiving electric power is connected in the connector33(seeFIG.2(B)). For example, the diameter of the detection surface32is made to be about 18 mm, and the length of the device housing31along the longitudinal direction is made to be about 35 mm. However, the shape and the size of the device housing31and those of the detection surface32are not limited to the above-mentioned example, and the device housing31may be variously constituted. For example, a part of the device housing31is enlarged so as to have a diametrically enlarged portion (see reference numerals34,35, and36) which is capable of performing clamping/fixing in order to prevent the occurrence of fluctuation of the detection distance. For example, it is possible to configure the device housing31to be clamped by providing nuts34,35and a washer36as the diametrically enlarged portion. Accordingly, the device housing31is capable of being separated into two parts from the diametrically enlarged portion.

The proximity sensor30needs to be provided close to an object for the purpose of detecting the object. In general, when the proximity sensor30is provided near an object (or a workpiece W) to be detected, a situation may occur in which the proximity sensor30collides with the workpiece W. In such a case, a breakage of the proximity sensor30may occur. Accordingly, the replacement frequency of the proximity sensor30is said to be relatively high. For example, the proximity sensor30may be replaced at a frequency of about once every three months.

In order to replace a cable (or a wiring) of the proximity sensor30, additional work is needed in two steps: fitting of a cable, and disposing of the cable (seeFIG.2(C)). In general, a plurality of cables for the proximity sensor30are provided in various lengths, such as 2 m, 5 m, 10 m or the like, and it is required to attach an arbitrary cable to a controller or the like according to the facility. The occurrence of the work means that a labor cost may be required for a worker in the factory. For example, according to some companies, it is estimated that the hourly wage of the worker may be 4000 Japanese Yen, and the loss for stopping the line may be 3 million Japanese Yen per minute.

In the present example, in order to address the above-described problems, the power-receiving device20is configured to receive energy E transmitted from the power-transmitting device10according to the microwave system in order to supply electric power to the proximity sensor30. However, there is an upper limit to the capacity of the energy to be transmitted according to the microwave system. In addition, there is a problem in that the efficiency of receiving energy is reduced as compared to the case of performing wired power supply. In addition, when performing wireless power supply between the power-transmitting device10and the power-receiving device20, the amount of power to be transmitted is attenuated in inverse proportion to the square of the distance between the two devices10,20according to Friis transmission formula.

In general, the proximity sensor30may be operated in a range from about 12V to about 24V and in a range from about 3 mA to about 1000 mA. In other words, when converted into electric power, the power consumption of at least about 36 mW may be required. However, when performing wireless power supply according to the microwave system, electric power of only about 1 mW to 10 mW may be supplied to a target through a distance of one meter. That is, in order to perform wireless power supply with regard to the proximity sensor30, reducing the power consumption of the proximity sensor30may become an issue.

The above-mentioned problem of the “reducing the power consumption of the proximity sensor” may be solved by newly developing a proximity sensor30having low power consumption for specific use. However, in general, a period of about 1 year to 5 years may be required in order to newly develop a product.

Therefore, for example, in the manufacturing industries, the products for consumer equipment are often applied to the products for automobiles. In such a case, a required period may be reduced to about one year.

In the present example, it is estimated that a conventional or existing proximity sensor30which is applicable in a range from 12V to 24V is used as it is, thereby eliminating the need for newly developing a proximity sensor having low power consumption. For this purpose, the applicant performed the below-mentioned tests.

Firstly, the applicant performed tests to verify how an existing proximity sensor30which is applicable in a range from 12V to 24V may work when electric power lower than the recommended electric power is supplied to the existing proximity sensor30.

With referring toFIG.3(A), changes in the electric power of the proximity sensor with respect to changes in the supplied voltage (or supply voltage) are depicted when voltage lower than the recommended value is supplied to two different types (which are referenced by reference numerals a and b) of commercially available proximity sensors which are applicable in a range from 12V to 24V. In the figure, values of supplied voltage (V) are depicted on the horizontal axis, and values of electric power (mW) are depicted on the vertical axis.

When the supplied voltage is lowered to about 6V with respect to the existing proximity sensors which are applicable to 12V to 24V, it is verified that the existing proximity sensor may operate as specified. Normally, when an object is detected, the power of the proximity sensor is made to be Low (L). At this time, as the supplied voltage becomes smaller, the power consumption becomes smaller. However, the occurrence of the power consumption of about 30 mW is still confirmed.

With referring toFIG.3(B), subsequently toFIG.3(A), changes in the electric power of the proximity sensor are illustrated when supplied voltage is further decreased. As depicted in the figure, when the voltage is lowered to about 5.2V, the power consumption becomes about 6 mW. In other words, it is confirmed that the proximity sensor30may work as long as there is the supply amount of about 10 mW.

In this way, when the supplied voltage is reduced from the recommended value with respect to the existing proximity sensors which are applicable to 12V to 24V, it is verified that the power requirement may be satisfied. Accordingly, it becomes possible to avoid the need for researching and developing a new proximity sensor which is applicable to about 5V to 6V. However, it is confirmed that the proximity sensor may work differently when the supplied voltage is reduced as compared with the case of the normal condition (in other words, when the sensor works at about 12V to 24V, as it is recommended).

With referring toFIG.4(A), output waveforms of the proximity sensor30are depicted when the supplied voltage is considerably lowered (for example, equal to or less than 6V) from the recommended value, as illustrated inFIG.3(B). As can be seen from the figure, when an object (as a detection target) is not in the vicinity of the sensor, the output voltage appears as positive (see V0). On the contrary, when an object is detected, the output voltage appears as large negative (see V1). In an ordinary use condition, when an object is detected, the output voltage of the proximity sensor is maintained in the lowered condition of “Low output for detecting an object”. However, as illustrated inFIG.3(B), when the supplied voltage which is considerably lowered from the recommended value is supplied to the sensor, it is confirmed that the above-mentioned condition of “Low output for detecting an object” is not maintained in the entire time-domain of the detection, but an intermittent operation is performed. That is, it is confirmed that the proximity sensor may periodically output the output voltage in the positive (see V0) and in the negative (see V1) alternately, even though the object is continuously detected by the sensor. Supposing that the period of the intermittent operation is made to be Tperiod, then it is conformed that the output-voltage-waveforms downwardly appear at every period Tperiodwhen the object is detected.

Furthermore, the Applicant performed other tests to confirm the regularity of the above-mentioned intermittent operation of the proximity sensor.

With referring toFIG.4(B), a graph is depicted for the above-mentioned case ofFIG.4(A). In this figure, values of supplied voltage (V) are depicted on the horizontal axis, and values of time (msec) are depicted on the vertical axis. As a consequence, it is found that the period Tperiodof the intermittent operation illustrated inFIG.4(A) has a relationship as shown in the graph ofFIG.4(B). That is, according to one type of the proximity sensor (type a), it is found that as the supplied voltage becomes smaller from 6V, the size of the period Tperiodbecomes larger almost proportionally to the voltage drop. It is confirmed that the same result may be obtained for another type of the proximity sensor (type b). Accordingly, it is found that there is a relationship between the intermittent operation of the proximity sensor and the periodic variation thereof.

Hereinafter, it is supposed that a condition in which the proximity sensor performs an intermittent operation when the supplied voltage of the proximity sensor is considerably lowered from the recommended value is referred to as a “low power mode (a mode in which the operation of the sensor is enabled with about one-fifth of power consumption of the conventional normal operation mode)”. In addition, it is supposed that a condition in which the supplied voltage of the proximity sensor satisfies the recommended value and the proximity sensor does not perform the intermittent operation is referred to as a “normal power mode”. It is also supposed that the low power mode may include a condition in which the operation of the sensor is enabled with power consumption in a range from about ⅕ to less than 1/1 compared with the conventional normal operation mode.

In the low power mode, it is confirmed that the proximity sensor30may perform the intermittent operation (seeFIG.4(A)). As a result, problems may occur when the output of the sensor is used as it is. Accordingly, the present example makes efforts to distinguish a condition in which an object exists, and a condition in which there is no need to detect an object (for example, an object does not exist) or an object is detected after a long time interval (for example, an object is replaced), by devising a circuit. That is, the period Tperiodof the intermittent operation appears at relatively short intervals as illustrated inFIG.4(A). The size of the time interval is substantially proportional to the supplied voltage, as illustrated inFIG.4(B). Accordingly, it becomes possible to estimate the size of the time interval according to the supplied voltage. Therefore, based on the fact that the intermittent operation of the proximity sensor is able to be predicted based on the supplied voltage, it becomes possible to determine whether or not the proximity sensor is detecting an object.

With referring again toFIG.1(B), it is illustrated that the power-receiving system1is configured to include the power-receiving device20, the proximity sensor30, a periodic filter40, and a controller50. In this circuit, the output of the proximity sensor30is passed through the periodic filter40and then it is transmitted to the controller50. The periodic filter40is an electric element which is capable of distinguishing a condition in which changes of High/Low are relatively fast (for example, the condition corresponds to the low power mode, at the time when an object is detected) and a condition in which the changes do not exist (for example, when there is no object).

For example, with referring toFIG.4(B), it is illustrated that voltage of 5.5V is supplied to the proximity sensor (a). At this time, it is predictable that the proximity sensor (type a) performs the intermittent operation at the period Tperiodof 20.4 msec. Accordingly, the output of the proximity sensor30is made to be passed through the periodic filter40in accordance with the size of the period. As a result, when the proximity sensor30detects an object W in the low power mode and performs the intermittent operation, the output may be used in the same way as the case of the normal power mode

Therefore, according to the present power-receiving system1, it is possible to avoid the occurrence of the erroneous recognition of the sensor output even when the conventional proximity sensor30which is applicable in a range from about 12V to about 24V is operated in the low power mode (for example, in a range from about 5V to about 6V).

However, the power-receiving system1is not limited to the configuration illustrated inFIG.1(B). The power-receiving system1is applicable to various types of devices (for example, sensors or actuators)30, and the device30may be operated in the normal power mode in addition to the low power mode depending on the kinds of the devices30. Therefore, the power-receiving system1may not necessarily include the periodic filter40.

Hereinafter, the power-receiving device20for being used in the power-receiving system1illustrated inFIGS.1to4will be described. In the present example, the power-receiving device20is configured as a power-receiving antenna. In particular, the power-receiving antenna is configured by using a device housing31(seeFIG.2(A)) constituting a main body of the device30to which electric power is supplied. Accordingly, the power-receiving device20is provided integrally with the device30.

FIGS.5to7schematically illustrate an overall configuration of the power-receiving device20.

InFIG.5(A), a dipole antenna21for being used as the power-receiving device20is illustrated. For example, the dipole antenna21is attached to the device housing31of the proximity sensor30. The dipole antenna21is made to function as an antenna for generating electric field radiation. In general, the proximity sensor30is configured to have a metal device housing (or metal body)31. With regard to this, a metal should not be arranged in a periphery of the dipole antenna21, but a resin or the like (which is not a metal) should be arranged thereabout.

InFIG.5(B), a slot antenna22for being used as the power-receiving device20is illustrated. For example, an arbitrary cavity is provided in the metal device housing31of the proximity sensor30. Accordingly, a slot is formed so as to penetrate a wall portion of the device housing. The slot antenna is made to function as an antenna for generating electromagnetic field radiation.

InFIG.5(C), it is exemplified that the dipole antenna21and the slot antenna22may be used in combination as the power-receiving device20. In this case, the dipole antenna21and the slot antenna22are arranged continuously and linearly along the longitudinal direction. It is illustrated that the two antennas21,22may have a length of about 300 mm, as a whole.

The dipole antenna21and the slot antenna22illustrated inFIG.5(C) are mutually aligned along the same direction. However, the working direction of the dipole antenna21and that of the slot antenna22appear orthogonal to each other. The dipole antenna21mainly acts on the basis of the electric fields, and the slot antenna22mainly acts on the basis of the magnetic fields, so that the respective working directions intersect with each other.

With referring toFIG.6, the simulation results of the power-receiving conditions of respective antennas are depicted in the three-dimensional space, with regard to the power-receiving device20(seeFIG.5(C)). InFIG.6(A), the directivity of the dipole antenna21is schematically illustrated, and inFIG.6(B) the directivity of the slot antenna22is schematically illustrated. In these figures, it is illustrated that as the color becomes darker, the intensity of the directivity of each antenna becomes stronger. As can be seen from the figures, an omnidirectional antenna may be configured as a whole, by combining the two different types of antennas21,22for constituting the power-receiving device20.

For example, when viewed from the X-axis direction inFIG.6(A), it can be seen that the dipole antenna21has an area in which the directivity of the antenna is decreased or weakened, as indicated by the reference numeral21A. On the other hand, when viewed from the X-axis direction inFIG.6(B), it can be seen that the slot antenna22has an area in which the directivity of the antenna is increased or strengthened, as indicated by the reference numeral21B. The two areas21A,21B overlap each other so that the area of the dipole antenna21where its function is dropping may be complemented by the area of the slot antenna22when viewed from the X-axis direction.

Also, for example, when viewed from the Y-axis direction inFIG.6(A), it can be seen that the dipole antenna21has an area in which the directivity of the antenna is increased, as indicated by the reference numeral22A. On the other hand, when viewed from the Y-axis direction inFIG.6(B), it can be seen that the slot antenna22has an area in which the directivity of the antenna is decreased, as indicated by the reference numeral22B. The two areas22A,22B overlap each other so that the area of the slot antenna22where its function is dropping may be complemented by the area of the dipole antenna21when viewed from the Y-axis direction.

Further, for example, when viewed from the Z-axis direction inFIG.6(A), it can be seen that the dipole antenna21has an area in which the directivity of the antenna is increased, as indicated by the reference numeral23A. On the other hand, when viewed from the Z-axis direction inFIG.6(B), it can be seen that the slot antenna22has an area in which the directivity of the antenna is decreased, as indicated by the reference numeral23B. The two areas23A,23B overlap each other so that the area of the slot antenna22where its function is dropping may be complemented by the area of the dipole antenna21when viewed from the Z-axis direction.

In this way, the directivity of the dipole antenna21and that of the slot antenna22do not appear uniformly in the three-dimensional space. The two directivities appear with various intensities, respectively, and each of the distributions is different. Accordingly, by properly combining the two distributions, it becomes possible to complement an area(s) where the directivity of the dipole antenna21is weakened by an area(s) of the slot antenna22, and vice versa. Therefore, the two antennas21,22are configured to mutually complement different directivities of the two antennas. As a result, the combination of the antennas21,22is constituted to be capable of receiving electric power in almost all directions without particularly showing a lack of directivity, as a whole. It is possible to achieve this constitution only by arranging the two antennas21,22in a straight line, as illustrated inFIG.5(C), and it is not necessary to adjust both orientations in a complicated manner.

With referring toFIG.7, the simulation results of the above-mentioned dipole antenna21and the slot antenna22are illustrated. In this figure, values of frequencies (GHz) are depicted on the horizontal axis, and values of efficiencies of the antennas are depicted on the vertical axis (supposing that efficiency of the perfect (ideal) antenna is 100%). As can be seen from the figure, it is verified that each antenna may have high efficiency of more than about 99% when the frequency is varied in a range from 0.8 GHz to 1.0 GHz. Accordingly, it is confirmed that the power-receiving device20illustrated inFIG.5(A) to (C) is capable of suitably receiving electric power.

Next, a more specific example of the power-receiving device20will be described with referring toFIGS.8to10, with regard to the above-mentioned power-receiving device20schematically illustrated inFIGS.5to7.

With referring toFIG.8, a perspective view of the proximity sensor30which is integrally provided with the power-receiving device20according to the present example is illustrated. This figure corresponds to an implementation example in which the dipole antenna21and the slot antenna22are combined (seeFIG.5(C)).

As illustrated inFIG.5(A), a dipole antenna21is provided as the power-receiving device20, at one end portion of a metal device housing31of the proximity sensor30. In general, the proximity sensor30is configured to include a metal connector33for performing wired power supply (seeFIG.2). It is possible to use this portion for mounting a dipole antenna21on the device housing31. The dipole antenna21is configured to have a rod-shaped main body so as to extend linearly along the longitudinal direction of the device housing31.

In the conventional proximity sensor30, a cable for wiring is made to extend from the end portion opposite to the detection surface32of the device housing31(seeFIG.2(C)). The present example is configured to eliminate the need for such a cable. As a result, it becomes possible to attach the dipole antenna21to the end portion of the device housing31by using a space for the eliminated cable. At this time, the metallic material of the conventional connector33of the proximity sensor may be used as a GND of the antenna.

In this way, the dipole antenna21may be attached to the device housing31by replacing the conventional connector33.

As illustrated inFIG.5(B), a longitudinal slot is formed in the metal device housing31of the proximity sensor30so as to extend in the longitudinally direction. As a result, a slot antenna22is provided as the power-receiving device20. This slot is provided to penetrate a wall of the device housing31along the thickness direction of the device housing31. This slot extends linearly along the longitudinal direction of the device housing31, but is provided not to penetrate the end portion of the device housing31(see reference numeral37).

In a case when a slot is formed to penetrate the device housing31, it is possible to cover a coil, a circuit or the like provided in the device housing with a metal or a resin in order to protect the internal coil, circuit or the like from the intrusion of oil.

Also, in a case when the device housing31is made of a non-metal material, it is possible to attach or add a metal film or a metal part to the slot penetrating the wall of the device housing31. In such a case, the slot is capable of functioning as the slot antenna22.

As illustrated inFIG.5(C), the dipole antenna21and the slot antenna22are arranged so as to be linearly continuous with each other along the longitudinal direction of the device housing31of the proximity sensor30. In the height direction of the proximity sensor30, the dipole antenna21and the slot antenna22are offset from one another (see reference numeral38). This height difference is made not to cause any particular disadvantage in the directivity of each antenna.

As described above, the device housing31has a size in the three-dimensional space (in the X-axis direction, the Y-axis direction, and the Z-axis direction), and the expansion of the size of the device housing31in the three-dimensional space due to the provision of the power-receiving devices21,22is substantially limited to one axis direction (for example, the X-axis direction) at most (in practice). Especially in the case of the slot antenna22, the expansion of the size of the device housing31is completely eliminated.

Therefore, according to the present example, it becomes possible to attach the power-receiving device20on the device housing31of the proximity sensor30without significantly changing the configuration of the conventional proximity sensor30. The power-receiving device20preferably includes the dipole antenna21and the slot antenna22, and is capable of receiving energy E from any direction. Each of the antennas21,22may be functionally connected to a rectifier in the device housing31. The rectifier is an electrical element having a rectifying function for sending a current of electricity only in one direction. The rectifier is capable of converting electromagnetic waves (RF) received by the antennas21,22into direct voltages (DC). The rectifier(s) may be integral with the antenna(s)21,22. Also, as described below, the rectifier may be integral with a chip antenna. In this way, the antennas21,22rectify microwaves and convert them into direct currents.

In a case when the proximity sensor30is used in a machine100or the like in FA (Factory Automation), it is required to have an oil resistance. When oil is used in the vicinity of the machine100, or inside or outside the machine100, oil may splash to the device housing31of the proximity sensor30, and thus the corrosion thereof may become a problem. Therefore, the material of the device housing31of the proximity sensor30is selected in consideration of the oil resistance. In the present example, the antenna (the dipole antenna21and/or the slot antenna22) may be incorporated in the device housing31of the proximity sensor30in view of the specific issues in FA. At this time, by arranging the antenna by utilizing the metal of the device housing31, it becomes possible to have advantages peculiar to the wireless power supply based on the microwave system from the point of view of energy harvest.

With referring toFIG.9, the simulation results of the power-receiving conditions of respective antennas21,22in the three-dimensional space are illustrated, based on the configuration illustrated inFIG.8. InFIG.9(A), the directivity of the dipole antenna21is illustrated, and inFIG.9(B), the directivity of the slot antenna22is illustrated. In each figure, it is illustrated that as the color becomes darker, the intensity of the directivity of each antenna21,22becomes stronger.

As can be seen fromFIG.9, similar to the case illustrated inFIG.6, an area of the slot antenna22where the directivity of the antenna is decreased may be complemented by an area of the dipole antenna21where the directivity of the antenna is increased. Also, an area of the dipole antenna21where the directivity of the antenna is decreased may be complemented by an area of the slot antenna22where the directivity of the antenna is increased. Accordingly, the two antennas21,22of different types are configured to complement each other to cover areas where their directivities are weakened. As a result, the antennas21,22are constituted to be capable of receiving electric power in almost all directions without particularly showing a lack of directivity, as a whole.

As described above, the verification is conducted by performing simulations for the omnidirectional antenna which is usable as a factory antenna utilizing the radiation characteristics of the dipole antenna21and the slot antenna22. As a result, although the respective antennas21,22are arranged in the same direction (along the longitudinal direction of the proximity sensor), it is confirmed that these radiation patterns are formed in shapes extending in directions orthogonal with each other at 90 degrees. Therefore, the present example is capable of forming an omnidirectional antenna by using the existing shape of the conventional sensor30as it is.

With referring toFIG.10, the simulation results of the power-receiving device20illustrated inFIG.8are illustrated. In this figure, values of frequencies (GHz) are depicted on the horizontal axis, and values of efficiencies of the antennas21,22are depicted on the vertical axis (supposing that efficiency of the perfect (ideal) antenna is 100%). As can be seen from the figure, it is verified that the dipole antenna21may have a high efficiency of about 99% and the slot antenna22may have a high efficiency of about 86%, when the frequency is varied in a range from 0.8 GHz to 1.0 GHz. Therefore, it is verified that the configuration using the combination of the slot antenna21and the dipole antenna22illustrated inFIG.8is particularly preferable.

The explanation is given about the power-receiving device20including the antennas21,22which is configured by using the existing shape of the device housing31of the conventional proximity sensor30as it is. The application of the power-receiving device20is not limited to the proximity sensor, but is applicable to other types of devices (including sensors and actuators)30.

In addition, it is possible to provide only one of the antennas21,22in the example illustrated inFIG.8, as illustrated inFIG.5(A), (B).

When energy E is transmitted from the power-transmitting device10to the power-receiving device20, the power-receiving efficiency of the power-receiving device20is lowered comparing to the case when energy is transmitted by wire, as being known to those skilled in the art. For example, when performing wireless power supply, only about 0.4% of power may be received at 1 m destination, in a space.

Hereinafter, with referring toFIGS.11to14, a means for improving the power-receiving efficiency of the power-receiving device20will be described when it is used.

With referring toFIG.11(B), it is exemplified that the power-transmitting device10and the power-receiving device20are separated from each other and are accommodated in a chamber (or a box)90that defines a closed space of a rectangular parallelepiped shape.

The chamber90is used to confine the power-transmitting device10and the power-receiving device20in a enclosed space defined in the chamber90. Accordingly, the efficiency of wirelessly transmitting energy E between the two devices is improved.

Although not shown in the figure, the chamber90is capable of accommodating all or a part of the machine100illustrated inFIG.1.

InFIG.11(B), it is illustrated that the chamber90has a rectangular parallelepiped shape or a polygonal shape, but the shape thereof may be variously changed according to the embodiment. For example, one or a plurality of corners of the chamber90may not be configured at right angles, and chamfering or the like may be performed thereto. Therefore, the number of side surfaces of the chamber90is not limited to six. Further, the shape of each side surface of the chamber90is not limited to a quadrangle.

With referring toFIG.11(C), the simulation results of the movement of electromagnetic waves in the chamber90illustrated inFIG.11(B) are illustrated. With referring toFIG.11(A), the situation at that time is illustrated.

As illustrated inFIG.11(C), the electromagnetic waves transmitted in the chamber90are reflected on each side surface defining the boundary of the chamber90. Eventually, the electromagnetic waves are innumerably reflected in the enclosed space, and the energy is confined within the chamber90. As a result, the power-receiving device20is capable of receiving energy transmitted from the power transmission device10from various directions. Therefore, the power-receiving device20is capable of receiving energy in a plurality of directions compared to the case where energy is received only from one direction without using the chamber90(see reference symbol E inFIG.1(A)).

With referring toFIG.12, the simulation results of the chamber90illustrated inFIG.11are illustrated. In this figure, values of frequencies (GHz) are depicted on the horizontal axis, and values of efficiencies (dB) of the antennas are depicted on the vertical axis. During the course of the simulations, five parameters (see S1,1, S3,1, S2,2, S3,2, and S3,3inFIG.14) are taken and the magnitudes are given in dB. According to the simulation results, it can be seen that, it is possible to enhance the performance at least five times when the wireless power supply is performed in the chamber90. Further, it is also confirmed that, in general, it is possible to enhance the performance nearly six times when the wireless power supply is performed in the chamber90.

It is possible to confine energy by using the chamber90. In addition, the present example is provided with a means for concentrating energy toward the power-receiving device20.

With referring toFIG.13(A), (B), it is exemplified that a stirring fan91is installed at a ceiling portion of the chamber90as a means for reflecting electromagnetic waves. The stirring fan91is configured to have a pair of reflecting surfaces93,94which are provided to rotate about a rotation shaft92like a fan or a propeller. In this example, each of the pair of reflecting surfaces extends in the opposite directions each other along the longitudinal direction so as to extend linearly as a whole. However, the number, the size, the shape, and the angle, etc., of the reflecting surfaces93,94may be varied depending on the embodiment.

As illustrated inFIG.13(A), the stirring fan91is capable of reflecting electromagnetic waves which are escaped to the ceiling upward from the lower portion of the chamber90at the surfaces of the reflecting surfaces93,94so as to transmit the energy to the lower portion again. Accordingly, the power-receiving device20is capable of receiving the energy directly transmitted from the power-transmitting device10, the energy transmitted by being reflected at the walls of the chamber90, and the energy transmitted by being reflected from the stirring fan91.

The reflecting surfaces93,94are configured as moveable parts so that the surfaces93,94are capable of following changes in positions of the power-receiving device20. For example, as illustrated inFIG.13(A), (B), the pair of the reflecting surfaces93,94may rotate about the central rotation axis92so as to change the relative position of the stirring fan91with respect to the chamber90.

Therefore, as illustrated inFIG.1(A), when the power-receiving device20changes the relative position with respect to the power-transmitting device10, the stirring fan91is capable of rotating in accordance with changes in positions, thereby changing the positions of the reflecting surfaces93,94. As a result, the power-receiving device20is capable of constantly receiving energy with high efficiency following changes in positions of the power-receiving device20.

For example, as illustrated inFIG.13(A), in a case when the pair of the reflecting surfaces93,94extend substantially straight along the longitudinal direction of the chamber90, it becomes possible to reflect and transmit the energy which is escaped upward from the power transmission device10further in the longitudinal direction (along the long axis direction of the power transmission device10). For this reason, when the rectilinearity of energy is required at the time of being transmitted, this case is preferable.

In addition, as illustrated inFIG.13(B), when the pair of the reflecting surfaces93,94extend in a substantially intersecting direction to the longitudinal direction of the chamber90, it becomes possible to reflect and transmit the energy which is escaped upward from the power transmission device10to a direction (along the short axis direction or the lateral direction of the power transmission device10) intersecting the longitudinal direction.

Further, the pair of the reflecting surfaces93,94is capable of being rotated about the central rotation axis92to variously adjust the position and the direction for reflecting the energy.

With referring toFIG.13(A), (B), it can be seen that a fixed reflective surface(s)95may be further provided on a side surface(s) of the chamber90.

As discussed above, each side surface of the chamber90is capable of reflecting electromagnetic waves. The reflecting surface95is configured to reflect electromagnetic waves with a reflectance which is different from that of the side surface of the chamber90. By changing the reflective efficiency of each side surface of the chamber90, it becomes possible to reflect electromagnetic waves so as to be more concentrated toward the power-receiving device20in the chamber90. For example, the reflective surface95may be configured as a metasurface (meta-surface). In this way, the reflective surface may be used in order to maximize electric power to be received by the power-receiving device when performing wireless power supply over an intermediate distance or a long distance.

With referring toFIG.14, it is illustrated that a metasurface96is provided on a side surface of the machine100as a fixed reflective surface.

In a case of the machine (or robot)100used in FA (seeFIG.1), the robot arm unit110, the robot hand unit120, and the main body, etc., of the robot100, are made of metallic material. Accordingly, a plurality of reflected waves (or reflecting surfaces) may exist around the robot100. Therefore, as illustrated inFIG.14(A), it is possible to reflect electromagnetic waves toward the power-receiving device20by using the reflected waves.

In addition, as illustrated inFIG.14(B), it is possible to further provide a metasurface96on a side surface of the machine100. Accordingly, electromagnetic waves may be further concentrated toward the power-receiving device20. As illustrated inFIG.14(C), the metasurface96is configured by arranging a plurality of small elements98on a substrate97. Each element98is defined in the shape and the arrangement to have a suitable reflective efficiency. Accordingly, the metasurface96is capable of reflecting electromagnetic waves and collecting them toward the power-receiving device20. As a result, it becomes possible to more efficiently transmit energy which is transmitted from the power-transmitting device10to the power-receiving device20.

As described above, the power-receiving device20of the present example is configured to form an omnidirectional antenna by using the existing shape of the conventional device (which may be a sensor or an actuator)30as it is. It is possible to improve the power-receiving efficiency of the power-receiving device20by using the chamber90when performing wireless power supply. In addition, the stirring fan91may be provided in the chamber90when the electromagnetic fields are required to be uniform. In addition, the metasurface (s)95and/or96may be provided on a side surface of the chamber90and/or a main body of the robot100used in FA, in order to more efficiently improve the receiving efficiency of the power-receiving device20.

With referring toFIG.15, a modification of the power-receiving system1illustrated inFIG.1(B) is exemplified. The system1exemplified in the figure is configured to include the power-receiving device20for wirelessly receiving energy transmitted from the power-transmitting device10, the device (for example, a proximity sensor)30to which electric power is supplied from the power-receiving device20, the device40for adjusting the output of the device30(for example, the periodic filter), and the controller50.

The proximity sensor30is configured to generate signals when it recognizes positions of an object W according to changes in magnetic fields. In the low power mode, periodic signals (H/L) are generated, as described above. However, signals (L) similar to those in the normal power mode may be obtained by passing periodic signals through the periodic filter40. Accordingly, by generating the signals, the controller50is allowed to use the output results of the proximity sensor30without performing false recognition.

The controller50is configured to have a microcomputer and a wireless communication function. The controller50is capable of transmitting signals which are sent from the proximity sensor30to an external controller60so as to be used for controlling a machine tool70. The machine tool70may be all or a part of the machine100. Alternatively, the machine tool70may be another machine.

As described above, the device30is made to be functioned by being supplied with energy by performing wireless power supply. Accordingly, in a case when data transmission of the device30is also made to be functioned by being supplied with energy by performing wireless power supply, the device30will be fully functional.

For example, as illustrated inFIG.3(B) andFIG.4(B), it is possible to estimate that the proximity sensor30may be operated with electric power of about 6 mW, and data transmission thereof may be operated with electric power of about 1 mW. Therefore, in a case when energy of about 7 mW is supplied to the proximity sensor30from the power-receiving device20, by performing wireless power supply, the device may be fully functional. When performing wireless power supply based on the microwave system, it is possible to supply electric power of about 10 mV to a target through a distance of one meter. Therefore, it is possible to fully function the device30by performing wireless power supply. The above is also applicable to another sensor or actuator that is different from the proximity sensor30.

As illustrated inFIG.1(B), the power-receiving device20may supply electric power to only the device30. Alternatively, as illustrated inFIG.15, the power-receiving device20may supply electric power to the periodic filter40and the controller50in addition to the device30.

Additionally, one or a plurality of power sources may be provided to the power-receiving system1. For example, as illustrated inFIG.15, it is possible to combine an oscillation power generation element80with the proximity sensor30in order to secure the power supply voltage of the proximity sensor30at least.

Various modifications may be made to the power-receiving system1illustrated inFIGS.1(B),15. In these figures, the periodic filter40is included in order to fully function the device30by performing wireless power supply, without requiring a new development of a proximity sensor. However, the periodic filter40may be dispensed according to the embodiment of the device to be powered.

In addition, it is known that, for example, as illustrated inFIG.4(B), the constant of the filter depends on the supplied voltage (which is substantially equal to the received electric power) of the proximity sensor30. Accordingly, it is possible to expand the power-receiving system1illustrated inFIGS.1(B),15so as to feed forward the information to the periodic filter40or the controller50.

As described above, with referring toFIGS.5to10, the power-receiving device20is configured to utilize the radiation characteristics of the dipole antenna21and/or the slot antenna22. However, the power-receiving device20is not limited to this example.

Hereinafter, with referring toFIGS.16to20, other examples of the power-receiving device20illustrated inFIGS.5to10will be described. In the examples, the power-receiving device20is at least one of a dipole antenna, a slot antenna, a monopole antenna, a chip antenna and an inverted-F antenna.

With referring toFIG.16(A), a perspective view is illustrated in which a short dipole antenna210is provided as the power-receiving device20on the device housing31of the device (for example, proximity sensor)30.

Depending on the mounting place of the device, it is not desirable to extend the dipole antenna210to project significantly outward from the device housing31. Therefore, in the example ofFIG.16(A), the dipole antenna210is provided with a relatively short length so as to suppress a portion protruding from the device housing31. As described above, the dipole antenna210may be configured by using the connector33of the conventional proximity sensor30.

In the example ofFIG.16(A), as a difference from the example illustrated inFIG.8, a slot antenna is not provided on the device housing31. Accordingly, the device housing31is configured to be completely sealed, and therefore, when the device housing is applied to the machine100in FA etc., the surrounding oil or the like is completely prevented from entering the device housing31.

With referring toFIG.16(B), the simulation results of the above-mentioned dipole antenna210having a shorter length (seeFIG.16(A)) are illustrated. As can be seen from the figure, it is possible to obtain the almost same directivity of the antenna, as in the case ofFIG.9(A), even when the length of the dipole antenna210is kept relatively short.

With referring toFIG.17(A), a perspective view is illustrated in which a slot antenna220is formed as the power-receiving device20on the device housing31of the proximity sensor30. In this figure, the portion that is completely blackened corresponds to the dipole antenna210illustrated inFIG.16(A), and this portion is provided to compare the position and the size of the antenna illustrated inFIG.17(A) with those of the antenna illustrated inFIG.16(A).

As is known to those skilled in the art, the device housing31of the proximity sensor30may be variously configured by the manufacturers. In the present example, the slot antenna220is formed by using an existing device housing31of the conventional proximity sensor30as it is. However, it is also possible to design a new device housing31having a slot, instead.

For example, in the example illustrated inFIG.8, there is a step (see reference numeral38inFIG.8) in the device housing31. Accordingly, the length of a slot that is horizontally drilled on the device housing31may be limited.

In the example ofFIG.17(A), as a difference from the example illustrated inFIG.8, a relatively large device housing31is provided without having a step (see reference numeral38inFIG.8), so that the device housing31is allowed to extend straight in the horizontal direction. Accordingly, it becomes possible to drill a slot having a sufficient length in the longitudinal direction. For example, a slot of any length up to about 70%, up to about 80%, up to about 90%, or up to about 100% may be drilled with regard to the entire longitudinal length of the device housing31(which is measured from one end of the side34to the other end of the side33of the body31).

When a slot is formed on the device housing31, it is possible to cover a coil, a circuit, or the like provided in the device housing with a metal or a resin in order to protect the internal coil, the circuit, or the like from the intrusion of oil.

With referring toFIG.17(B), the simulation results of the above-mentioned slot antenna220(seeFIG.17(A)) are illustrated. As can be seen from the figure, it is possible to obtain the almost same directivity of the antenna, as in the case ofFIG.9(B), even when the length of the slot antenna220is made to be large.

Comparing the cases ofFIG.16(B) andFIG.17(B), it is confirmed that the directivity of the dipole antenna210and that of the slot antenna220cross each other. This is the same as the cases illustrated inFIG.6(A), (B) andFIG.9(A), (B).

With referring toFIG.18(A), a perspective view is illustrated in which a monopole antenna230is provided as the power-receiving device20on the device housing31of the proximity sensor30. In this figure, the portion that is completely blackened corresponds to the dipole antenna210illustrated inFIG.16(A), and this portion is provided to compare the position and the size of the antenna illustrated inFIG.18(A) with those of the antenna illustrated inFIG.16(A). The monopole antenna230is also referred to as a rod antenna, and is configured to be smaller in diameter and longer in length in comparison with the dipole antenna210.

In order to ensure the power-receiving efficiency of the monopole antenna230, it is necessary to secure the length thereof, and therefore, in the present example, one end portion of the monopole antenna230is mounted on the device housing31in the vicinity of the nuts34,35and the washer36for fastening and fixing the device housing31, and the other end portion of the monopole antenna230is extended straight in the opposite direction. By aligning the extending direction of the device housing31and the extending direction of the monopole antenna230, the overall size is suppressed from becoming bulky, as a whole.

With referring toFIG.18(B), the simulation results of the above-mentioned monopole antenna230(seeFIG.18(A)) are illustrated.

Comparing the cases ofFIG.16(B) andFIG.18(B), it is confirmed that the directivity of the dipole antenna210and that of the monopole antenna230appear in the same direction. It is also confirmed that excellent directional characteristics may be obtained even when the monopole antenna230is used instead of the dipole antenna210. In addition, comparing the case ofFIG.17(B) and that ofFIG.18(B), it is confirmed that the directivity of the monopole antenna230and that of the slot antenna220cross each other.

With referring toFIG.19, a comparison between the size of the conventional proximity sensor30illustrated inFIG.2(B) and the size of the monopole antenna230illustrated inFIG.18(A) is depicted.

As illustrated inFIG.19(A), the device housing31of the conventional proximity sensor30extends in the longitudinal direction, and it is supposed that the size thereof is made to be L0. The device housing31of the proximity sensor30has an enlarged diameter portion (see reference numerals34,35, and36) for fastening and fixing on one end side, and also has a connector33on the other end side.

As illustrated inFIG.19(A), the monopole antenna230is provided close to the enlarged diameter portion for fastening and fixing, and is made to extend along the longitudinal direction of the device housing31toward the other end portion33in the same direction (or parallel to the longitudinal direction of the device housing31). Consequently, the length L1of the elongated monopole antenna230is able to be embedded in the longitudinal length L0of the device housing31for the length L2up to the end portion33of the device housing31which is opposed to the enlarged diameter portion for fastening and fixing. Accordingly, the size of the extending length L3of the device housing31along one axial direction in the three-dimensional space due to adding of the monopole antenna230to the device housing31may be set not longer than 2 times of the length L0at most. In another example, the size of the extending length L3along one axial direction in the three-dimensional space may be set not longer than 1.5 times of the length L0of the device housing at most. Further, it is possible to substantially suppress the size of the length L3to zero by allowing the part of the length L1to be foldable.

As illustrated inFIG.19(B), the monopole antenna230is completely accommodated in the original size of the device housing31in the width-direction WO of the device housing31. Therefore, there is no change in the size of the device housing31on the side of the working surface (or detection surface32) of the sensor30. On the other side of the sensor30opposite to the working surface, the length of the device housing31is extended, but the need for wiring (seeFIG.2(C)) is eliminated. As a result, the problem of the space by providing the length L3is substantially suppressed.

Therefore, the device housing31has a size in the three-dimensional space (in the X-axis direction, the Y-axis direction, and the Z-axis direction), and expansion of the size of the device housing31in the three-dimensional space due to the provision of the monopole antenna230is substantially limited to one axis direction (X-axis direction) at most.

With referring toFIG.20, for the three types of modified examples illustrated inFIGS.16to19, the power-receiving efficiencies of these antennas are illustrated, respectively. As can be seen from the figure, when only the dipole antenna210having a relatively short length is provided, the power-receiving efficiency is the lowest. Also, when the slot antenna220is provided, the power-receiving efficiency exceeds 80% (although it does not reach 90%), and it is found that relatively good power-receiving efficiency may be obtained. Further, when the monopole antenna230is provided, the power-receiving efficiency is greatly increased, and it is found that an ideal value close to 100% may be obtained.

When the proximity sensor30is attached in a movable member such as the robot hand unit120, the position and the direction of the power-receiving antenna may be changed variously. In order to maintain the power supplying condition of the proximity sensor30satisfactorily in the three-dimensional space, it is desirable that the power-receiving device20is capable of maintaining good power-receiving efficiency in each of the six directions (for example, six directions of front-rear directions, left-right directions, and up-down directions) in the three-dimensional space.

It is found that when only the dipole antenna210having a shorter length is provided, good power-receiving efficiency may be obtained only by a relatively small angle, with respect to changes in rotation angles. However, it may exhibit relatively good stability in six directions, as a whole.

When the monopole antenna230is provided, the best power-receiving efficiency may be obtained (seeFIG.20). However, an elongated rod-shaped component is needed to be attached to the proximity sensor30. Accordingly, the structure tends to be bulky as a whole. In particular, the monopole antenna230has a smaller diameter and a longer entire length as opposed to the case of the dipole antenna210. Therefore, when it is used, it is necessary to secure a space so as not to be damaged by, for example, the elongated rod-shaped antenna portion being in contact with other components.

When the slot antenna220is provided, it is found that a much better power-receiving efficiency may be obtained as compared with the case of the dipole antenna210having a shorter length (seeFIG.20) although the power-receiving efficiency of the slot antenna220is not as excellent as that of the monopole antenna230. In the case of the slot antenna220, there is no need to protrude an additional component from the device housing31of the proximity sensor30as compared with the cases of the dipole antenna210and the monopole antenna230. Accordingly, the slot antenna220offers the advantage of being the most compact structure as a whole, and of maintaining the original size of the device housing31of the conventional device30as it is.

Further, with referring toFIG.31, another example is illustrated in which an inverted-F antenna400is provided as the power-receiving device20on the device housing31of the device (for example, proximity sensor)30. As illustrated in the figure, the inverted-F antenna400is configured to have an elongated body portion410, a shorting portion (or shorting point)420, and a feed portion (or feed point)430. The longitudinal direction (for example, along the X-axis direction) of the main body portion410is aligned with the longitudinal direction of the device housing31so that the projection from the device housing31due to the provision of the inverted-F antenna400is suppressed. The body portion410is able to contribute to matching and to radiating (for receiving electric power). It is possible to adjust the input impedance (for example, for increasing it) by making flow a relatively large current through a tip of the main body portion410and the shorting portion420while preventing a current flowing through the feed portion430.

It is possible to attach the inverted-F antenna400to the device30without requiring a large space. For example, the inverted-F antenna400may be configured to be shorter compared to the simple monopole antenna230(seeFIGS.18,19). In addition, the inverted-F antenna400may make it easier to control impedance matching. The inverted-F antenna400offers a large number of adjustment parameters in its configuration. Accordingly, it is possible to cope with various specifications by selecting its appropriate configuration.

For example, it is possible to adjust the separation or distance between the shorting portion420and the feed portion430.

Also, it is possible to adjust the width or length of the shorting portion420and that of the feed portion430.

Also, it is possible to exchange of the positions of the shorting portion420and the feed portion430. In other words, it is possible to reverse the two (as the shorting portion430and the feed portion420).

Also, it is possible to constitute the body portion410narrower (in an almost rod shape) and to adjust the length thereof.

Also, it is possible to provide a curved part in the body portion410. For example, it is possible to form the body portion410in an approximately L-shape.

Also, it is possible to constitute the body portion410wider (in an almost plate shape) and to adjust the length thereof.

The power-receiving device20may include a slot antenna (seeFIG.17) that mainly generates magnetic fields and an inverted-F antenna (seeFIG.31) that mainly generates electric fields. The slot antenna and the inverted-F antenna may be aligned along the substantially same direction, and the slot antenna and the inverted-F antenna may constitute an omnidirectional antenna having two power-receiving patterns (or radiation patterns) substantially orthogonal to each other.

Further, instead of the dipole antenna, the slot antenna, the monopole antenna, and the inverted-F antenna illustrated inFIGS.16to19and31, it is also possible to provide a chip antenna (not illustrated) having a planar or linear body to the device housing31of the device in the same manner. For example, a linear chip antenna may be considered similar to the above-mentioned monopole antenna.

In addition, in a case when the dipole antenna, the monopole antenna, the inverted-F antenna400, or the chip antenna is provided to the device housing31of the device, a cover500for covering the elongated antenna portion may be provided in combination therewith (seeFIG.31). The cover500is capable of having an arbitrary size and/or shape in order to protect the antenna portion from being contacted with surrounding components or the like. The cover500may be configured to be detachable from the device housing31so as to be removed when the antenna is used.

As stated above, the cases where at least one of a dipole antenna, a slot antenna, a monopole antenna, an inverted-F antenna, and/or a chip antenna is provided in a sensor are explained.

Hereinafter, a case where a slot antenna is provided in an actuator will be explained.

With referring toFIG.21(A), an actuator is exemplified as a device30to which electric power is supplied from the power-receiving device20. The actuator300is a mechanical element that includes a mechanical and/or electrical circuit for converting electrical signals into physical movements. For example, the actuator300is configured to have a device housing310that constitutes a main body of a substantially rectangular. The device housing310extends in the longitudinal direction and defines a space therein to accommodate a working portion or movable portion350of the actuator300. The working portion350is capable of performing movements such as expansion/contraction, bend/stretch, and/or rotation, by being operated by a physical device using a machine, oil pressure, air pressure, heat, or electromagnetic, etc.

With referring toFIG.21(B), a cross-sectional view of the actuator300is schematically illustrated. The working portion350that is accommodated in the device housing310is capable of electromagnetically functioning according to the input signal so as to protrude a moving portion352outward from the inside of the device housing310with respect to the fixed portion354. The movements of an adjacent component (not shown) may be controlled by operations of protruding/retracting of the moving unit352.

As illustrated inFIG.21(A), the actuator300has a rectangular parallelepiped device housing310. It is possible to add one or a plurality of additional surfaces to the rectangular parallelepiped shape for dealing with its design and/or function. For example, a plurality of fixing grooves311-318extending along the longitudinal direction are provided by drilling on four side surfaces of the device housing310. The grooves311to318may act in pairs with other protrusions (not shown) for fixing the device housing310at a predetermined position in order to prevent the occurrence of shifts in the operations of the working portion350. In addition, arbitrary grooves or holes321to324may be provided by drilling on the side surface of the device housing310as appropriate, depending on the embodiment. Further, it is possible to process the device housing310in order to add surface treatment to one or a plurality of surfaces of the device housing310for releasing heat from the inside of the device housing310to the outside or to enhance the design quality thereof.

With referring toFIG.21(A), a first slot (notch)330extending in the longitudinal direction is formed in at least one of the four side surfaces of the device housing310. A space is defined in the interior of the device housing310for accommodating the working portion350therein. The first slot330penetrates the wall of the device housing in the thickness direction and reaches the space along the depth direction. As a result, the first slot330is capable of functioning as a first slot antenna.

With referring to the same figure, a second slot (notch)340extending in a direction orthogonal to the longitudinal direction is formed in at least one of the four side surfaces of the device housing310. The second slot340penetrates the wall of the device housing in the thickness direction and reaches the space along the depth direction. As a result, the second slot340is capable of functioning as a second slot antenna.

The second slot340may be provided as a bisector perpendicular to the first slot330. Accordingly, the first slot330and the second slot340cross each other in a cross shape. By providing the two slot antennas330and340in this way, these antennas may become stronger with regard to its rotation as a whole.

The length, the position, and the number of the first slot330and those of the second slot340are determined in consideration of the radiation patterns of electromagnetic waves.

For example, with referring toFIG.21(A), the first slot330is provided to extend only in the upper side surface. However, the first slot330may further extend over four side surfaces of the upper side, the right side, the left side (not shown), and the lower side (not shown). Therefore, the number of the first slots330may be plural.

The second slot340is provided to extend over three side surfaces of the upper side, the right side, and the left side (not shown). However, the second slot340may further extend over four side surfaces of the upper side, the right side, the left side (not shown), and the lower side (not shown). Therefore, the number of the second slots340may be plural.

The first slot330and the second slot340each extend straight parallel to the side surfaces of the device housing310in order to facilitate machining of these slots330,340. However, in other examples, the first slot330and the second slot340may be provided to extend at an angle on any of the side surfaces of the device housing310for dealing with its design and/or function.

In addition, the first slot330and the second slot340are not completely separated from each other and partially intersect each other. However, in other examples, the two slots330,340may be provided to be completely separated from each other.

Preferably, however, the first slot330and the second slot340are orthogonal to each other at an angle of 90 degrees.

With referring toFIG.23(A), (B), the simulation results of electromagnetic fields of directivities of the two different slot antennas330,340(seeFIG.22(A)) in the three-dimensional space are illustrated. During the course of the simulation, it is supposed that electric power is supplied at positions E1, E2inFIG.21. As a result, it is verified that each of the antennas330,340appears as an omnidirectional antenna. In addition, the strengths of the directivities of the antennas330,340are shifted from each other. Therefore, by using the two antennas330,340in combination, the directivities may be mutually complemented.

With referring toFIG.23, the simulation results of radiation efficiencies of the two different slot antennas330,340(seeFIG.21) are illustrated. During the course of the simulation, it is supposed that electric power is supplied at positions E1, E2inFIG.21. In general, it is verified that each of the antennas330,340may have a high efficiency of 70% to 80%. For example, a high-efficiency of about 80% may be achieved at E1and a high-efficiency of about 75% may be achieved at E2, at a frequency of 0.92 GHz, respectively.

With referring toFIG.24, the simulation results of impedance characteristics of the actuator300(seeFIG.21) are illustrated. In general, it is verified that good changes in impedance characteristics may be achieved by electric power received by the antenna330,340. For example, the impedance may be suppressed to a value close to 0Ω at a frequency of 0.92 GHz.

Therefore, omnidirectional antennas330and340may be obtained only by performing a drilling, cutting or boring process to the device housing310of the conventional actuator300. At this time, another component is not additionally provided to protrude from the device housing310so that the mounting space of the conventional actuator300is not changed. In particular, there is no configuration change on the working surface side (working portion350) of the actuator. Accordingly, the device of the present example may be used substantially in the same manner as the conventional actuator300.

However, it is possible to additionally provide a monopole antenna, a dipole antenna, a chip antenna or an inverted-F antenna or the like on the device housing310, in addition to the above-mentioned slot antennas330,340or instead of the slot antennas330,340in the example illustrated inFIG.21.

In the above-mentioned actuator300illustrated in FIGS.21to24, the slot antennas330,340are provided by boring slots on the device housing310.

With referring toFIGS.25to30, a modified example is exemplified with regard to the actuator300having the slot antennas330,340.

With referring toFIG.25, a perspective view of the actuator300is illustrated. Hereinafter, only differences from the actuator300illustrated inFIG.21(A) will be described.

The first slot antenna330and the second slot antenna340are provided by drilling on the device housing310of the actuator300. In addition, each of the slot antennas330,340is provided with a substrate (or board)360,370of an IC for receiving electric power for improving the power-receiving efficiency.

With referring toFIG.26(A), (B), a cross-sectional view of the front surface side and that of the side surface side of the actuator300(seeFIG.25) are schematically illustrated. As can be seen from the figures, bolts361,362and a rectifier363are provided on the substrate360. Similarly, it can be seen that bolts371and372and a rectifier373are provided on the substrate370. These rectifiers363,373may be provided as integrated with chip antennas, respectively.

InFIG.26, it is illustrated that the substrates360,370for feeding electric power are provided. However, actually, the slots330,340formed on the device housing310serve as antennas. By providing a chip antenna, an inverted-F antenna, a monopole antenna, and/or a dipole antenna, etc., on the substrates360and/or370, it becomes possible to generate respective patterns of electric fields and/or magnetic fields. As a result, it becomes possible to realize a coverage of 360 degrees. Therefore, it is possible to attain space saving of the device by minimizing the space required to add an antenna thereon, and to achieve an omnidirectional antenna (for receiving electric power from 360 degrees around). Thus, the actuator300which is capable of receiving electric power without having an antenna protruding to the outside is configured as a wireless power feeding actuator to be used as an antenna-less actuator (which is not provided with a protruding antenna).

Two bolts361,362are provided on the substrate360, and also two bolts371,372are provided on the substrate370. The two bolts361,362are juxtaposed on the substrate360along the lateral direction, and the two bolts371,372are juxtaposed on the other substrate370along the longitudinal direction. Each of the pair of the bolts361,362and the pair of the bolts371,372is capable of passing a current of electricity, and the two pairs are arranged orthogonally to each other. The number of the bolts361,362, and371,372on each of the substrates360and370may be two or more. These bolts are not provided with surface coating. However, the bolts may be provided with surface coating under the conditions of short-circuiting of the conductors, and no loosening of the screws even when the robot moves abruptly.

As described above, each of the slot antennas330,340is configured to generate radiation at the slot portion so that each slot is capable of functioning as an antenna. During the course of the function, each of the bolts361,362, and371,372on the substrates360and370functions to send a current of electricity therethrough. Each of the rectifiers363and373is an element having a rectifying function of sending a current of electricity only in one direction, and of converting electromagnetic waves (RF) received by the antennas330,340into DC-voltages (DC). A chip antenna may be further provided integrally on each of the substrates360,370. The two bolts361,362, and371,372are provided on each of the substrates360and370, respectively, but the number thereof may vary depending on the embodiment.

There are two types of chip antenna: a linear chip antenna like a dipole antenna or a monopole antenna; and a planar chip antenna. In the present example, a planar chip antenna is provided. The chip antenna is capable of being provided by using a metal portion of the device housing310of the actuator300, as it is. Therefore, the area efficiency of the device may be improved as compared with the cases of the dipole antenna and the monopole antenna. In addition, various materials may be used to the chip antenna, and for example, ceramics or the like may be used thereto.

With referring toFIG.27(A), (B), the simulation results of electromagnetic fields of directivities of the antennas in the three-dimensional space are illustrated with regard to the two different slot antennas330,340and the substrates360,370(seeFIG.25). As in the cases ofFIG.22(A), (B), each of the antennas330,340appears as an omnidirectional antenna. The strengths of the directivities of the antennas330,340are shifted from each other. Therefore, it is possible to mutually complement these directivities by using the two antennas330,340in combination.

With referring toFIG.28, the simulation results of radiation efficiencies are illustrated with regard to the two different slot antennas330,340and the substrates360,370(seeFIG.25). As in the case ofFIG.23, it is confirmed that, in general, each of the antennas330,340may achieve a high efficiency of close to 70%. It is illustrated that the results ofFIG.23correspond to an ideal power feeding, but the results ofFIG.28correspond to a more realistic power feeding. Accordingly, in the case ofFIG.28, the efficiency is slightly lowered comparing to the case ofFIG.23.

With referring toFIG.29, the simulation results of impedance characteristics are illustrated with regard to the actuator (seeFIG.25). It is confirmed that, in general, good changes in impedance characteristics may be obtained due to electric power received by each antenna330,340and the substrate360,370. For example, the impedance may be suppressed to a value close to 0Ω at the frequency of 0.92 GHz.

With referring toFIG.30, the simulation results of electric current distributions on surfaces are illustrated for the actuator300(seeFIG.25). It is illustrated that, generally, currents are suitably distributed along the positions of the antennas330,340, respectively. Therefore, it is verified that each antenna330,340may excellently act in practice.

With referring toFIGS.32(A), (B), it is exemplified that a light-emitting diode (LED)600is able to be provided on the main body310of the actuator300. The LED600is connected to the output of the power-receiving device via a switch (not shown). The LED600is configured to light up when the LED600is energized by voltages above a predetermined threshold. The lighting of the LED600is made to be visually confirmed from the outside of the actuator300.

Accordingly, a user (for example, an inspector) is allowed to easily understand the power-receiving condition of the power-receiving device based on the lighting of the LED600without performing an electric inspection. The intensity of the light emitted by the LED600is approximately proportional to the amount of the current of electricity flowing therethrough. It is preferable to minimize the frequency or the duration of the lighting of the LED600in order to prevent wasting of available power for performing wireless power supply. The LED600may be switched on, before or after the start of the use of the power-receiving device in order to minimize the effect of the lighting on the power feeding operation.

Alternatively, it is possible to provide an acoustic device (not shown) such as a buzzer or the like on the main body310of the actuator300instead of the LED600. Similarly, a buzzer may be configured to sound when voltages above a predetermined threshold flow therethrough. Therefore, a user (for example, an inspector) may easily understand the power-receiving condition of the power-receiving device according to the volume of the buzzer without performing an electrical inspection.

With referring toFIG.33, it is illustrated that an inverted-F antenna700is provided on the device housing310of the actuator300. The device housing310has a size in the three-dimensional space (in the X-axis direction, the Y-axis direction, and the Z-axis direction), and expansion of the size of the device housing in the three-dimensional space due to the provision of the power-receiving devices is substantially limited to one axis direction (the Z-axis direction) at most.

Specifically, the device housing310has a substantially hexahedral structure, and the substrates740,750are provided for attaching the inverted-F antenna700on the upper surface of the device housing310. The size of each of the substrates740,750is substantially equal to the size of the upper surface (one side surface) of the device housing310, or is slightly bigger than the size of the upper surface at a small ratio (in the X-axis direction and the Y-axis direction). Especially, the back of the substrate740is made to be a ground substrate, and is short-circuited to the device housing310to effectively increase the ground size.

The inverted-F antenna700is configured to have a body portion710having a substantially L-shape (or angled shape), a long and narrow shorting portion720, and a feed portion730. It is possible to mount the inverted-F antenna700on the device housing310without requiring a relatively large space. For example, it is possible to configure the inverted-F antenna700to be shorter in the longitudinal direction (X-axis direction) as compared to the simple monopole antenna230(seeFIGS.18,19). The longitudinal direction of the main body portion710is aligned with the longitudinal direction (X-axis direction) of the device housing310. However, its tip portion extends in the width direction (Y-axis direction). It is possible to suppress the size in the width direction of the body portion710having a substantially L-shape to be equal to or smaller than the size in the width direction (Y-axis direction) of the device housing310. Therefore, the protrusion from the device housing in the three-dimensional space due to the provision of the inverted-F antenna700is suppressed in the X-axis direction and the Y-axis direction. The body portion710may be constituted to be substantially straight without having an angled portion, or may be formed in a substantially L-shape having only one angled portion. However, it is possible to increase the number of angled portions.

The shorting portion720, and the feed portion730are provided to connect the two substrates740,750in the vertical direction (the Z-axis direction). It is possible to adjust the distance between the shorting portion720and the feed portion730, and the width and the length of the shorting portion720and those of the feed portion730. It is also possible to replace the locations of the shorting portion720and the feed portion730. That is, it is possible to have a feed portion720and a shorting portion730. The control of the impedance matching may be executed more easily in the inverted-F antenna400. The reason is that, a plurality of adjustable parameters are provided in the inverted-F antenna400so that it is possible to cope with various specifications by selecting an appropriate shape of the inverted-F antenna400. The body portion710is able to contribute to matching and to radiating (for receiving electric power).

Also in this case, the power-receiving device20may include the slot antenna (seeFIGS.21,25) that mainly generates magnetic fields, and the inverted-F antenna (seeFIG.33) that mainly generates electric fields. The slot antenna and the inverted-F antenna may be aligned in substantially the same direction, and the slot antenna and the inverted-F antenna may constitute an omnidirectional antenna having two radiation patterns and/or power-receiving patterns substantially orthogonal to each other.

As described above, the present examples provide the device housings31,310for wirelessly receiving electric power for supplying electric power to the corresponding device30,300, while suppressing the expansion of the sizes of the devices30,300. In addition, the present examples provide the devices30,300having the same device housings31,310.

The power-receiving device20provided on the device housings31,310is at least one of a dipole antenna, a slot antenna, a monopole antenna, an inverted-F antenna, and a chip antenna (which may be a linear antenna or a planar antenna)

Preferably, the device housing31,310are configured to include the power-receiving device20having at least two of a monopole antenna, a dipole antenna, a slot antenna, an inverted-F antenna, and a chip antenna.

Preferably, the two antennas of the power-receiving device20are made to have different directivities from each other. Preferably, the two antennas are provided to constitute an omnidirectional antenna having different radiation patterns or power-receiving patterns substantially orthogonal to each other.

The power-receiving device20is configured such that a portion protruding to the outside from the device housings31,310is substantially limited to one axis direction at the maximum in the three-dimensional space (for example, see the X-axis direction inFIG.8, the X-axis direction inFIG.19, and the Z-axis direction inFIG.33). Alternatively, the power-receiving device20is configured such that a portion protruding to the outside from the device housings31,310is substantially eliminated (seeFIGS.21,25). As a result, in both the cases, the device may be treated in almost the same way as the conventional device30.

Preferably, in a case where the power-receiving device20is configured to have a portion protruding to the outside (see the X-axis direction inFIG.8), the protruding direction thereof is made to be aligned with the conventional wiring direction (see the wiring inFIG.2(C)). As a result, the usability of the device is not substantially impaired in almost the same way as the conventional device30.

Preferably, when the power-receiving device20is mounted on the device housing31,310of the device, it is configured not to interfere with the working surface of the device (see reference numeral32inFIG.8, and reference numeral350inFIG.21). As a result, the usability of the device is not substantially impaired in almost the same way as the conventional device30.

InFIG.33, it is illustrated that when the inverted-F antenna700is provided upward (in the Z-axis direction) from the upper surface of the device housing310, a part of the substrate740is made to protrude in a direction perpendicular to the protruding direction (in the X-axis direction and/or the Y-axis direction). However, the ratio of the protrusion (along the X-axis direction) of the substrate740is relatively small as a whole, and it is possible to ignore it in practice. For example, in a case when the protrusion is made to be equal to or less than about 10% of the size of the upper surface of the device housing310, it is possible to ignore the protrusion because it may not cause substantial damage in practice. Importantly, even if there is a slight protrusion (for example, along the X-axis direction) of the substrate740, the ratio of the protrusion is suppressed. As a result, the operation of the device300is not affected by it, and the mounting space thereof is not substantially increased.

The devices30,300to which electric power is supplied by the power-receiving device20is able to be operated in the low power mode as illustrated inFIG.4(or in a mode that enables the operation with about one-fifth of power consumption of a conventional normal operation mode). Alternatively, the devices30,300may be operated in the normal power mode (or in a mode that enables the operation with power consumption of the conventional operation mode). In addition, it may be possible to operate the devices30,300with power consumption of in a range of from about ⅕ to about 1/1 as compared to the conventional operation mode.

In practice, the power-receiving device20may be provided as a device (or an electric device) that is a sensor or an actuator. For example, it may be provided as the sensor30illustrated inFIGS.8,16-18or as the actuator300illustrated inFIGS.21,25.

Alternatively, the power-receiving device20may be provided as a device housing of a device that is a sensor or an actuator. For example, the present example may be applied to an existing sensor or actuator only by replacing a device housing thereof. For example, the present example may be provided as the device housing31to be used for the sensor30illustrated inFIGS.8,16-18or the device housing310to be used for the actuator300illustrated inFIGS.21,25.

The device housing31,310is defined as a housing (or a case) that forms a main body of the device. The above-mentioned device housings31,310are configured to fully accommodate the internal components (for example, a circuit, etc.) of the device. However, in some examples, it is not always necessary to completely accommodate the internal components of the device, but it is possible to expose one or a plurality of the components from the device housing.

Further, the power-receiving device20may be provided as a part of a device housing of a device that is a sensor or an actuator. For example, the present example may be applied only by replacing or attaching a part of a device housing of an existing sensor or actuator. It may be provided as the connector33to be used for the device housing31, for supplying electric power to the sensor30, as illustrated inFIGS.8,16-18. That is, it may be provided as the connector33for performing wireless power supply that is used by being replaced with a conventional connector for performing wired power supply.

Further, the power-receiving device20may be provided as a system1which is configured to include a device30to which electric power is supplied, and additional components (see reference numerals40,50inFIG.1Aand reference numeral80inFIG.15).

Further, the power-receiving device20may be provided as a machine100having a system1which is configured to include a device30to which electric power is supplied, and additional components (see reference numerals40,50inFIG.1Aand reference numeral80inFIG.15).

The power-receiving device20may be configured to allow the adjustment of the power-receiving condition of the antenna according to the embodiment. For example, the protruding length of the dipole antenna21illustrated inFIG.8or the protruding length of the monopole antenna230illustrated inFIG.18may be made to be changeable. The dipole antenna21illustrated inFIG.8, the monopole antenna230illustrated inFIG.18, and the linear chip antenna, etc., may be configured to be detachable, dividable, extendable and/or foldable.

In addition, for example, in the actuator300illustrated inFIG.25, each of the bolts361,362,371,372provided on the substrates360,370is capable of sending a current of electricity therethrough. The positions of the bolts361,362,371,372may be made to be adjustable. For example, when the bolts361,362,371,372are provided to be screwed into corresponding holes formed in the substrates360,370, the height of the bolts361,362,371,372may be changed by adjusting the screwed condition. Each of the protruding heights of the bolts361,362,371,372may be adjusted in order to obtain an optimum current value according to the power-receiving condition.

Further, for example, in the actuator300illustrated inFIG.25, the depth, the length, the width, and/or the feeding position of each of the slots330,340provided by drilling on the device housing310of the actuator300may be made to be adjustable. For example, when each of the slots330,340is provided by forming a recessed portion on the device housing310, the depth, the length, the width or the like thereof may be changed by fitting an arbitrary member in each of the slots330,340. The depth, the length, the width or the like of each of the slots330,340may be adjusted in order to obtain an optimum feeding position according to the power-receiving condition.

Further, for example, in the actuator300illustrated inFIG.25, the power-receiving condition of the antennae300may be made to be adjustable by providing an IC for receiving electric power on one or a plurality of the substrates360,370. The adjustment of the bolts361,362,371,372and the slots330,340may be configured to be performed manually or automatically.

Further, for example, in the actuator300illustrated inFIG.25, when the rectifiers363,373are provided on the substrates360,370, each of the rectifier363,373may have a negative impediment. In such a case, an IC for receiving electric power may be used to search for a positive feeding position in order to avoid the occurrence of the impedance-mismatching. The IC for receiving electric power may be configured to determine a feeding position according to the power-receiving condition in order to avoid the occurrence of the impedance-mismatching without using an impedance matching circuit.

Further, for example, in the present examples, the power-receiving system1or the power-receiving device20may be configured to include a CPU (or a processing device) and a memory (or a storage device) in order to perform the control of the above-described contents for adjusting the power-receiving condition of the antenna.

The CPU is generally defined as a device that executes software (or program). For example, The CPU is configured as a Neumann-type CPU. The CPU may be configured to include a control device for controlling the whole of the system/device, an arithmetic device, a register for temporarily storing data, an interface for a memory, and an interface for a peripheral device and an input/output device, etc.

The memory is defined as a device capable of storing data therein. For example, the memory is a primary storage device that is accessed directly by the CPU or a secondary storage device that is accessed by using an input/output channel, etc. For example, the memory may be configured to use an arbitrary medium, a fixed disc, a volatile or non-volatile random access memory, a CD, a DVD, a flash drive, a removable media (for example, a small thumb-sized memory) which is attachable to a corresponding interface (for example, a USB port) or the like.

Further, for example, the present example may be provided as a computer program product for controlling the power-receiving condition of the antenna, with regard to the above-mentioned power-receiving system1or the power-receiving device20.

The computer program product may be implemented as a program, a function, a routine, an executable object or the like.

Therefore, the present invention also relates to a computer program product for performing the above-described control.

The computer program product (for example, a computer program means or the like) may be implemented by using a memory card, an USB stick, a CD-ROM, a DVD, or a file that is downloadable from a server in a network. For example, such a file may be provided by transferring a file containing a computer program product through a wireless communication network.

A person skilled in the art may recognize that the above-described examples may be used or modified in a variety of ways without departing from the scope of the claims.

For example, each of the components of the power-receiving device20or the power-receiving system1may include different one or a plurality of components necessary for the operation, or may further include additional one or a plurality of components to provide one or a plurality of functions other than those described herein.

Therefore, it is feasible to practice the contents of the claims otherwise than as specifically described herein.

The above-mentioned examples disclose at least the following configurations.

A device housing constituting a main body of a device which is a sensor or an actuator is provided.

The device housing is provided with a power-receiving device for mainly generating an electric field and/or a magnetic field for performing wireless power supply.

The power-receiving device includes at least one of a dipole antenna, a slot antenna, a monopole antenna, a chip antenna and an inverted-F antenna.

In addition, the device housing has a size in a three-dimensional space, and expansion of the size of the device housing in the three-dimensional space due to the provision of the power-receiving devices is substantially limited to one axis direction at most.

For example, the size of the expansion of the device housing in the three-dimensional space due to the provision (or adding) of the power-receiving devices is substantially limited to one axis direction in practice (in a case of the dipole antenna, the monopole antenna, the linear chip antenna, or the inverted-F antenna).

Alternatively, for example, the size of the expansion of the device housing due to the provision of the power-receiving devices is substantially eliminated in practice (in a case of the slot antenna or the planar chip antenna).

Preferably, in a case that the size of the device housing is expanded along the one axis direction due to the provision of the power-receiving devices, the ratio of the expansion is suppressed.

For example, the size of the expansion may be set not longer than 2 times of the size of the device housing along the expanding direction. Or, the size of the expansion may be set not longer than 1.5 times of the size of the device housing along the expanding direction.

As a result, the devices30,300according to the present embodiments are capable of avoiding an expansion of the mounting space, and of being used almost the same way as the conventional device to which electric power is supplied with a wire.

The power-receiving device may include a slot antenna for mainly generating a magnetic field and a dipole antenna for mainly generating an electric field.

In addition, the slot antenna and the dipole antenna may be arranged substantially in a same direction.

Further, the slot antenna and the dipole antenna may form an omnidirectional antenna having two emission patterns or power-receiving patterns which are orthogonal to each other (seeFIGS.8,9).

The power-receiving device may include a slot antenna for mainly generating a magnetic field and a monopole antenna for mainly generating an electric field.

In addition, the slot antenna and the monopole antenna may be arranged substantially in a same direction.

Further, the slot antenna and the monopole antenna may form an omnidirectional antenna having two emission patterns or power-receiving patterns which are orthogonal to each other (seeFIGS.17,18).

The power-receiving device may include a first slot antenna for mainly generating a magnetic field and a second slot antenna for mainly generating a magnetic field.

In addition, the first slot antenna and the second slot antenna may be arranged substantially in intersecting directions.

Further, the first slot antenna and the second slot antenna may form an omnidirectional antenna having two emission patterns or power-receiving patterns which are orthogonal to each other (seeFIGS.21,22).

The power-receiving device may include a slot antenna for mainly generating a magnetic field and an inverted-F antenna for mainly generating an electric field.

In addition, the slot antenna and the inverted-F antenna may be arranged substantially in a same direction.

Further, the slot antenna and the inverted-F antenna may form an omnidirectional antenna having two emission patterns or power-receiving patterns which are orthogonal to each other (seeFIGS.8,31,21,33).

The power-receiving device may include a slot antenna for mainly generating a magnetic field and a chip antenna for mainly generating an electric field.

In addition, the slot antenna and the chip antenna may be arranged substantially in a same direction;

Further, the slot antenna and the chip antenna may form an omnidirectional antenna having two emission patterns or power-receiving patterns which are orthogonal to each other (seeFIG.25).

The power-receiving device may include at least two of the dipole antenna, the slot antenna, the monopole antenna, the chip antenna and the inverted-F antenna.

In addition, each of the antennas may be configured to have a substantially different emission pattern or power receiving pattern.

Especially, each of the two antennas21,22may be configured to have a different directivity of antenna so that areas of the two antennas where the directivities are weakened may be mutually interpolated.

The power-receiving device may be a slot antenna.

In addition, the expansion of the size of the device housing due to the provision of the power-receiving devices may be substantially eliminated.

Especially, when the slot antenna is provided on the device housing, it may be provided along the longitudinal direction of the device housing by drilling a wall of the device housing in the thickness direction (seeFIGS.17,21,25).

The device housing may be capable of including a metallic connecter for performing wired power supply (see reference numeral33inFIGS.8,2), and the connector may be provided with the power-receiving device.

In this case, it becomes possible to perform wireless power supply only by replacing a part of the device housing (see reference numeral33inFIGS.8,2), and to utilize the existing device housing in maximum.

The device housing may be provided with a chip antenna which is integrated with a rectifier (seeFIGS.25,26).

The device housing may be provided with a slot antenna and a bolt which is capable of passing a current of electricity (seeFIGS.25,26).

A device which is a sensor or an actuator is provided.

The sensor includes the above-mentioned device housing.

In addition, the device is capable of performing wireless power supply according to a microwave system.

A system including a device which is a sensor or an actuator; and a filter which is capable of receiving output of the device is provided.

The device includes the above-mentioned device housing.

In addition, the filter is used to enable operation of the sensor or the actuator with about one-fifth of power consumption of a conventional normal operation mode of the sensor or the actuator.

Alternatively, the device may be operated with power consumption of in a range of from about ⅕ to about 1/1 as compared to the conventional operation mode.

It is possible to operate the device by performing wireless power supply, and also operate the data transmission of the device by performing wireless power supply. Accordingly, it is possible to fully operate the device by performing wireless power supply thereto.

EXPLANATION OF REFERENCE NUMERALS