Power transmission apparatus, method for controlling the same, and program

A power transmission apparatus includes a power transmission unit configured to wirelessly transmit power to a power reception apparatus, a detection unit configured to detect an object present in a range of the power transmission apparatus where the power is transmitted based on an intermittent power transmission, and an authentication unit configured to authenticate whether the object detected by the detection unit is the power reception apparatus that receives the power, wherein the authentication unit authenticates the object detected as being present in the range where the power is transmitted at each of a plurality of times of the power transmission for detection during a predetermined period, and wherein the power transmission unit transmits the power to the power reception apparatus that has been successfully authenticated.

BACKGROUND

Field

Aspects of the present invention generally relate to wireless power transmission.

Description of the Related Art

In the related art, a wireless power transmission system including a power transmission apparatus that wirelessly transmits power and a power reception apparatus that receives the power supplied from the power transmission apparatus are known. Typically, the power transmission apparatus detects a power reception apparatus present in a range where power is transmitted for the purpose of detection. Authentication processing is then performed with respect to the detected power reception apparatus based on power transmission for authentication. When the authentication succeeds, regular power transmission starts (refer to Japanese Patent Application Laid-Open No. 2013-212004).

Since the wireless power transmission system wirelessly transmits the power, the power can be transmitted to an object present in a relatively wide range of area. Thus, it is necessary to detect the object present in the range where the power is transmitted. Therefore, even when the power reception apparatus just passes through the vicinity of the power transmission apparatus, the power transmission apparatus may detect the power reception apparatus and the authentication processing may be initiated. As a result, the power transmission apparatus sometimes performs processing for unnecessary power transmission to a power reception apparatus that just passes through the vicinity of the power transmission apparatus and does not need to receive power.

SUMMARY

A power transmission apparatus includes a power transmission unit configured to wirelessly transmit power to a power reception apparatus, a detection unit configured to detect an object present in a range of the power transmission apparatus where the power is transmitted based on an intermittent power transmission, and an authentication unit configured to authenticate whether the object detected by the detection unit is the power reception apparatus that receives the power. The authentication unit authenticates the object detected as being present in the range where the power is transmitted at each of a plurality of times of the power transmission for detection during a predetermined period. The power transmission unit transmits the power to the power reception apparatus that has been successfully authenticated.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

FIG. 1is a diagram of a configuration of a wireless power transmission system that performs wireless power transmission, according to the present embodiment. Note that the wireless power transmission system according to the present embodiment performs the wireless power transmission using a magnetic field resonance method. The magnetic field resonance method transmits power by a combination of magnetic field resonance (resonance) between a resonator (resonance element) of a power transmission apparatus and a resonator (resonance element) of a power reception apparatus. Note that, in the present embodiment, an exemplary wireless power transmission system using the magnetic field resonance method will be described. However, the wireless power transmission method (non-contact power transmission method) is not limited to the magnetic field resonance method. A power transmission method using, for example, electromagnetic induction, electric field resonance, a microwave, or a laser, may be used.

InFIG. 1, reference numerals101and102denote a power transmission apparatus and a power reception apparatus, respectively. The power transmission apparatus101wirelessly transmits power. The power reception apparatus102can receive the power wirelessly transmitted by the power transmission apparatus101. The power reception apparatus102includes a battery. The battery is charged with the power received from the power transmission apparatus101. Reference numeral110illustrates a range where the power by the power transmission apparatus101is transmitted. The wireless power transmission system according to the present embodiment performs communication for authentication and communicates control information for controlling the wireless power transmission between the power transmission apparatus and the power reception apparatus. Hereinafter, transmission and reception of the power between the power transmission apparatus and the power reception apparatus are expressed as power transmission, power reception, or power transmission (wireless power transmission). An exchange for the authentication and an exchange for the control information between the power transmission apparatus and the power reception apparatus are expressed as communication (wireless communication).

Communication that conforms to the Bluetooth® 4.0 standard is used between the power transmission apparatus and the power reception apparatus in the wireless power transmission system according to the present embodiment. Bluetooth® Low Energy (BLE) that can communicate with relatively low power consumption is defined in Bluetooth® 4.0. Note that, in the present wireless power transmission system, the power transmission apparatus serves as a central that is a master station of a network and is defined by the BLE. In order to simultaneously transmit power with respect to multiple power reception apparatuses, the power transmission apparatus needs to communicate with each power reception apparatus. In order to communicate with each power reception apparatus, the power transmission apparatus serves as the central. Each of the power reception apparatuses serves as a peripheral defined by the BLE. The peripheral is coupled to the central and communicates based on control by the central. However, note that the power transmission apparatus101may be the peripheral and the power reception apparatus102may be the central.

The communication performed in the present exemplary embodiment conforms to the BLE. However, the communication may conform to other communication standards, for example, a wireless LAN (The Institute of Electrical and Electronics Engineers, Inc (IEEE) 802.11 series). The communication according to the present embodiment may conform to near field communication (NFC) or ZIGBEE. The communication may conform to an original communication method, such as load modulation. Here, one power transmission apparatus and one power reception apparatus have been illustrated. However, two or more power transmission apparatuses and two or more power reception apparatuses may be provided.

Next, configurations of the respective apparatuses in the wireless power transmission system will be described.FIG. 2is a diagram of a configuration of the power transmission apparatus101in the wireless power transmission system. Reference numeral201denotes a control unit that controls the power transmission apparatus101. An example of the control unit201is a central processing unit (CPU) including a timer207and a memory208. The control unit201executes a control program stored in the memory208to control the entire power transmission apparatus. When the control unit201stores a variable value while executing the control program, the control unit201also uses the memory208. The control unit201uses the timer207when measuring time.

Reference numeral202denotes a power supply that supplies power when the power transmission apparatus101performs the wireless power transmission. The power supply202is a commercial power supply or a battery. Reference numeral203denotes a power transmission unit that converts direct current (DC) or alternating current (AC) power input from the power supply202into AC frequency power in a transmission band, and generates an electromagnetic wave that is sent through a power transmission antenna205. Based on an instruction from the control unit201, the power transmission unit203adjusts the intensity of the electromagnetic wave to output via the power transmission antenna205, where the different intensities are used for power transmission for detection, power transmission for authentication, power transmission in a power transmission phase, etc. as described below. The power transmission unit203also performs control, based on an instruction from the control unit201, to stop the power transmission from the power transmission antenna205.

Reference numeral204denotes a detection unit that detects an input voltage to the power transmission antenna205. The voltage detected by the detection unit204can be converted into power output from the power transmission antenna205to an object present in a range where the power is transmitted. The detection unit204can include a configuration that detects an input current value or an input power value to the power transmission antenna205. The detection unit204can include a configuration that detects at least one of an input voltage value, an input current value, or an input power value from the power supply202to the power transmission unit203.

The power transmission apparatus101can determine, based on a detection result detected by the detection unit204, whether the object receiving the power output from the power transmission apparatus101has been placed on a charging stand103which is in the range110. In a case where the object receiving the power is in the range110, the object receives (consumes) part of the power output from the power transmission unit203, and the detection unit204detects a value different from that in a stationary state. Stationary state refers to the object that receives the power not having been placed in the range110.

Reference numeral206denotes a communication unit that communicates with the power reception apparatus102. The communication unit206includes a chip for controlling wireless communication that conforms to the BLE, and an antenna for transmitting a signal. Reference numeral209denotes a notification unit that issues an information notification to a user. The notification unit209includes a function that displays, based on an instruction from the control unit201, the information on a liquid crystal display (LCD) (not shown). The notification unit209may provide the notification information in another manner other than via the LCD. For example, the notification information may be provided via a speaker, where audio is used to provide the information notification to the user.

The power transmission apparatus101is not limited to just being an apparatus that transmits power. For example, it can be any type of apparatus, such as a printer, a personal computer, etc.

Next, a configuration of the power reception apparatus102in the wireless power transmission system will be described usingFIG. 3. Reference numeral301is a control unit that controls the power reception apparatus102. The control unit301is a CPU that includes a timer307and a memory308like the control unit201. A communication unit306includes a chip for controlling the wireless communication that conforms to the BLE, and an antenna for transmitting a signal. Reference numeral305denotes a power reception antenna for receiving the wireless power transmission from the power transmission apparatus101. Reference numeral303denotes a power reception unit that generates power from the electromagnetic wave received by the power reception antenna305. The power reception unit303generates resonance due to the electromagnetic wave received by the power reception antenna305, and obtains AC power due to the resonance. The power reception unit303then rectifies the AC power to a DC power or an AC power with a desired frequency to output the DC power or the AC power with the desired frequency. Reference numeral302denotes a rechargeable battery. The rechargeable battery302is charged with the power received by the power reception apparatus102. Reference numeral304denotes a detection unit that detects a voltage across the battery302. Based on the detected voltage, the control unit301detects whether the battery302has been fully charged and a charging state of the battery302.

The control unit301and the communication unit306in the power reception apparatus102may operate with the power transmitted by the power transmission apparatus101. With this configuration, even when the power reception apparatus102maintains no power necessary to start the wireless power transmission from the power transmission apparatus101, the power reception apparatus102can start to communicate with the power transmission apparatus101. Examples of the power reception apparatus102may be an apparatus, such as a digital camera or a mobile phone, but are not limited to these types of apparatuses.

The configurations illustrated inFIGS. 2 and 3are just examples. The power transmission apparatus101and the power reception apparatus102may include hardware configurations other than the illustrated hardware configurations. For example, both the power transmission apparatus101and the power reception apparatus102may include an operation unit requiring a user to perform various kinds of input to, for example, operate the apparatus.

An exchange between the power transmission apparatus101and the power reception apparatus102in the wireless power transmission having the above configurations includes three phases: a detection phase, a communication establishing phase, and a power transmission phase.

In the detection phase, the power transmission antenna205intermittently generates the electromagnetic wave so that power transmission for detecting the power reception apparatus102(power transmission for detection) is intermittently performed. When an object is placed in the range where the power is transmitted, of the power transmission apparatus101in a case where the power transmission for detection is performed in the detection phase, the power transmission for detection is supplied to the object. In this case, load impedance viewed from the side of the power transmission apparatus101varies. As a result, a distinctive change occurs in a voltage or a current in the power transmission apparatus101. Therefore, detecting the change of the voltage or the current in the power transmission apparatus101results in detecting that the object has been placed in the range where the power is transmitted. When the power transmission apparatus101detects that there is the object in the range where the power is transmitted, power transmission for supplying power necessary for authentication processing (power transmission for authentication) starts with respect to the detected object. When the detected object is the power reception apparatus102, a power value is substantially large for activating the control unit301and the communication unit306in the power reception apparatus102. The power value of the power transmission for authentication is substantially larger than that of the power transmission for detection.

In the power reception apparatus102that has received the power transmission for authentication, the communication unit306transmits an advertising packet within a certain period, for example, 100 ms, after the power transmission for authentication. The advertising packet causes another apparatus to transmit a communication connection request. When receiving the advertising packet from the power reception apparatus102that has responded to the power transmission for authentication, the power transmission apparatus101determines that the power reception apparatus102is in the range where the power is transmitted.

The advertising packet is a signal to which broadcast transmission is performed and that is defined by the BLE. The advertising packet includes information, such as an apparatus name, a kind of service to be provided, and a version of a protocol used for the communication. The advertising packet is used to notify a peripheral apparatus of the presence and an indication for waiting for connection from the peripheral apparatus. The advertising packet from the power reception apparatus102includes service information indicating that the wireless power transmission method handled by the present system can be performed. In the following descriptions, the advertising packet is referred to as a notification signal.

When the power transmission apparatus101does not receive the notification signal from the power reception apparatus102within a predetermined period, for example, 100 ms, from a start of the power transmission for authentication, the power transmission apparatus101stops the power transmission for authentication. The power transmission antenna205intermittently generates the electromagnetic wave again so that the power transmission for detection is intermittently performed.

In the detection phase, when the power transmission apparatus101detects the notification signal from the power reception apparatus102, the phase proceeds to the communication establishing phase. The power transmission apparatus101transmits, from the communication unit206, a connection request packet (connection request) to the power reception apparatus102that is a transmission source of the notification signal received by the power transmission apparatus101. Then, the power transmission apparatus101establishes communication connection with the power reception apparatus102in accordance with the transmitted connection request. Then, authentication processing is performed between the apparatuses using the established communication connection. The authentication processing communicates (exchanges) mutual capability information during a period of the communication connection established between the power transmission apparatus101and the power reception apparatus102. The capability information includes, for example, an amount of the power that can be transmitted and received, a hardware configuration, a handling power transmission method, or a version of a handling power transmission standard. The BLE periodically generates a chance for exchanging a data packet. The chance is referred to as a connection event. The power transmission apparatus101requires, by the data packet to be transmitted at the first connection event, the power reception apparatus102to notify the power transmission apparatus101of a necessary power value. In order to satisfy the request, the power reception apparatus102includes the necessary power value in a next data packet and transmits the necessary power value.

In the authentication processing, when a version of a protocol of the power transmission apparatus101corresponds to that of the power reception apparatus102, and when power required by the power reception apparatus102is substantially less than or equal to power the power transmission apparatus101can transmit, the authentication succeeds. Otherwise, the authentication fails. When information necessary for the authentication is not acquired from the power reception apparatus102within a predetermined time after the power transmission for authentication is started, the authentication also fails. In a case where the authentication processing communicates, between the power transmission apparatus101and the power reception apparatus102, a password for performing the authentication, when either the power transmission apparatus101or the power reception apparatus102or both the power transmission apparatus101and the power reception apparatus102determine that the communicated password is correct, the authentication may succeed.

By the authentication processing, the power transmission apparatus101can confirm that the object present in the range where the power is transmitted is the power reception apparatus102requiring the power transmission. By the authentication processing, the power reception apparatus102can confirm whether the power transmission apparatus101to which the communication connection has been performed can supply the power. In the communication establishing phase, the power transmission apparatus101continuously performs the power transmission for authentication to perform the power transmission for performing communication of the capability information and communication necessary for the communication connection with respect to the power reception apparatus102.

The power transmission apparatus101establishes the communication connection with the power reception apparatus102in the communication establishing phase. When the power transmission apparatus101and the power reception apparatus102exchange the capability information, the phase proceeds to the power transmission phase. In the power transmission phase, the power transmission apparatus101transmits, to the power reception apparatus102, power substantially larger than those of the power transmission for detection in the detection phase and the power transmission for authentication in the communication establishing phase. In the power transmission phase, the power transmission apparatus101receives, by the communication unit206, the control information for controlling the wireless power transmission, such as a value of the power that has been received, a request for increase or decrease of power transmission capacity, or a stop of the power transmission, from the power reception apparatus102. That is, in the power transmission phase, the power transmission apparatus101performs power transmission corresponding to a request from the power reception apparatus102. When the power transmission apparatus101receives, from the power reception apparatus102, a signal that requires a stop of the power transmission or an error in the power transmission occurs, the power transmission phase is completed. The control information from the power reception apparatus102may include error information. For example, when receiving, from the power reception apparatus102, control information indicating that an error such as heat generation of the battery occurs, the power transmission apparatus101may stop the power transmission. In the following descriptions, the power transmission in the power transmission phase is referred to as power transmission for charging.

Operation of the wireless power transmission system that performs the wireless power transmission according to the present embodiment will be described using flowcharts illustrated inFIGS. 4 and 5.FIG. 4is the flowchart of operation of the power transmission apparatus101.FIG. 5is the flowchart of detection processing. The control unit201executes the control program stored in the memory208to perform a calculation and processing of information and control of each of piece of hardware. As a result, the flowcharts illustrated inFIGS. 4 and 5can be achieved. A part of the steps or the entire steps in the flowcharts illustrated inFIGS. 4 and 5may be constituted of hardware, such as an application specific integrated circuit (ASIC).

Processing illustrated inFIG. 4starts when power of the power transmission apparatus101is turned on. The processing illustrated inFIG. 4is completed when the power of the power transmission apparatus101is turned off.

When starting operation, the control unit201controls the power transmission unit203so that the power transmission antenna205outputs the power transmission for detection. Then, the control unit201continuously performs, during a predetermined time or more, the detection processing for detecting the object present in the range110where power is transmitted on the charging stand103illustrated inFIG. 1(S401). A detailed description of this processing will be given later.

When the detection processing detects the object, the control unit201controls the power transmission unit203so that the power transmission antenna205outputs the power transmission for authentication. Then, the control unit201performs the authentication processing. Furthermore, the control unit201controls the communication unit206to attempt the authentication by the above wireless communication (S402). After that, the control unit201determines whether the authentication has succeeded (S403).

When the authentication succeeds, the object detected in S401is determined as the power reception apparatus102. In this case, the power transmission unit203is controlled so that the power transmission antenna205outputs the power transmission for charging that is the power transmission in the power transmission phase. The power transmission for charging is performed until the communication unit206receives, from the power reception apparatus102, a request for stopping the power transmission (S404). When the power transmission is stopped, the control unit201notifies, by the notification unit209, the user that the charging has been completed (S405). Then, the control unit201controls the power transmission unit203so that the power transmission antenna205outputs the power transmission for detection. Next, the control unit201determines whether the placed object has been removed (S407). The processing returns to S401when the placed object has been removed.

When the authentication fails in S402, namely the detected object is not the power reception apparatus102, no power transmission for charging is output and the notification unit209notifies the user to remove the object having been placed on the charging stand103(S403and S406). Next, the control unit201controls the power transmission unit203so that the power transmission antenna205outputs the power transmission for detection. Then, the control unit201determines whether the placed object has been removed (S407). When the placed object has been removed, the processing returns to S401.

The detailed description of the detection processing in S401will be given using the flowchart inFIG. 5.

First, the control unit201initializes a continuous detection counter to zero (S501). The continuous detection counter counts the number of continuous detections of the object by the power transmission for detection. The value of the continuous detection counter is stored in the memory208. Next, the control unit201controls the power transmission unit203so that the power transmission antenna205outputs the power transmission for detection (S502). When the output of the power transmission for detection starts, the control unit201confirms whether the object has been placed in the range110on the charging stand103in accordance with whether a result detected by the detection unit204is a value different from that in the stationary state. When the object present in the range where the power is transmitted is detected, the control unit201increments the continuous detection counter by one (S503and S504). As a result, the control unit201determines that the object receiving the power has been continuously placed in the range110on the charging stand103for the predetermined time or more when the value of the continuous detection counter is greater than or equal to a predetermined value N, so as to complete the detection processing (S505).

The predetermined value N is used to define a predetermined period when the object continuously present, during the predetermined period, in the range where the power is transmitted, is detected. For example, in a case where a period during which the power transmission for detection is output is 100 msec, when it is detected that the object has been continuously placed for one or more seconds, N may be set to 11. The memory208stores the value of N. With consideration of a space of the range where the power is transmitted, the predetermined period defined by the predetermined value N is set to be longer than time during which the user holds the power reception apparatus and passes through the range where the power is transmitted. The user may arbitrarily set the predetermined value N.

In S503, when no object is detected in the range where the power is transmitted, the control unit201initializes the continuous detection counter to zero (S506). The control unit201controls the power transmission unit203so that the power transmission antenna205stops the power transmission for detection. Then, the control unit201holds during a certain period of time, for example, 100 msec (S507). The processing returns to S502. At S505, when the value of the continuous detection counter is less than the predetermined value N, while holding the value of the continuous detection counter, the control unit201controls the power transmission unit203so that the power transmission antenna205stops and holds the power transmission for detection during a certain period of time. After that, the processing is held for the predetermined time (S507) and then returns to S502.

According to the above processing, the control unit201intermittently outputs the power transmission for detection at the predetermined time interval to confirm whether there is an object that receives the power for each output each time. When the object that receives the power has been continuously detected during a plurality of times (more than N) of the output of the power transmission for detection, it is determined that the object has been continuously placed in the range110on the charging stand103for the predetermined time or more. Then, the processing proceeds to the next step. That is, due to each of the plurality of consecutive times of the power transmission for detection, the authentication processing can be performed just to the object that has been detected as being present in the range where the power is transmitted. Therefore, for example, even when a power reception apparatus that does not need the power transmission is temporarily present in the range where the power is transmitted as passing through the vicinity of the power transmission apparatus, the authentication processing is not performed to this power reception apparatus. As a result, processing for the unnecessary power transmission can be reduced.

Operation of the present wireless power transmission system in a case of N=3 as an example will be described usingFIGS. 6 and 7.FIG. 6is a diagram illustrating that, in accordance with a user's movement, the power reception apparatus102passes through the range where the power is transmitted, of the power transmission apparatus101, and then another power reception apparatus603is placed at the center of the charging stand103. The power reception apparatus102enters the range110on the charging stand103at time T1, and then moves out of the range110at time T2. Then, the power reception apparatus603enters the range110at time T3. Here, between time T1and time T2, the power transmission for detection is output twice.

FIG. 7is a graphical representation of a voltage detected by the detection unit204in this case. The vertical axis represents a detection voltage, and the horizontal axis represents time. The power transmission apparatus101intermittently outputs the power transmission for detection by the processing of S401before time T1. During this period, the detection unit204detects a voltage at the stationary state (701to703). During a period between time T1and time T2, since the power reception apparatus102is present in the range110on the charging stand103, the detection unit204detects a voltage different from the voltage at the stationary state (704and705). Accordingly, the control unit201detects placement of an object. When the power reception apparatus102moves out of the range110at time T2after the control unit201detects the placement of the object due to consecutive two times of the power transmission for detection, the detection unit204detects the voltage at the stationary states again (706). In this case, the control unit201initializes the continuous detection counter to zero in S506without selecting YES in S505after the value of the continuous detection counter to be stored in the memory208increases up to two. In other words, at this stage, the power transmission for authentication caused by the processing proceeding to S402inFIG. 4is not performed.

The power reception apparatus603then enters the range110at time T3. Next, when the power reception apparatus603stays in the range110, the detection unit204detects a voltage different from the voltage at the stationary state due to consecutive three times of the power transmission for detection (707to709). Since the continuous detection counter satisfies N=3 due to the third709, the processing proceeds to S402because YES is selected in S505inFIG. 5. Therefore, the power transmission for authentication is transmitted (S402,710). When the authentication succeeds, the power transmission for charging is transmitted (S404,711).

As described above, according to the present embodiment, even when the power reception apparatus102temporarily enters, along a trace601illustrated inFIG. 6, the range where the power is transmitted, of the power transmission apparatus101, the authentication processing is not performed. Therefore, the processing for unnecessary power transmission can be reduced. When the power reception apparatus603is placed in the range where the power is transmitted, of the power transmission apparatus101by following a trace602illustrated inFIG. 6, the authentication processing can be securely performed.

The power reception apparatus in which the battery is charged with the received power has been described above. However, the power reception apparatus may use the power received after the authentication succeeds, for other uses, such as driving of a motor.

Second Embodiment

FIG. 8is a diagram of a configuration of a power transmission apparatus801in a wireless power transmission system that performs wireless power transmission according to another embodiment. The power transmission apparatus801according to the present embodiment has the same configuration as that of the power transmission apparatus101except for a switch810. The switch810sets activation or inactivation for detection processing that detects an object having been continuously placed for predetermined time or more. The switch810can be set to two values: ON and OFF. In a case of OFF, power transmission for authentication is output and then authentication processing is performed immediately after an object is detected by single power transmission for detection. That is, in a case where the switch is set to OFF, the above predetermined value N is set to one.

Operation of the detection processing of the power transmission apparatus801illustrated inFIG. 5will be described. The same processing in S501and S502as that in the above first embodiment is performed. At S503, the power transmission apparatus801detects the object to confirm whether the switch810is ON or OFF. When the switch810is ON, a control unit201in the power transmission apparatus801initializes the predetermined value N to be stored in a memory208to a set value. The remaining processing is the same as that in the above first embodiment, and as such, a detailed description is omitted herein. When the switch810is OFF, the control unit201in the power transmission apparatus801changes the predetermined value N stored in the memory208to one. The remaining processing is the same as that in the above first embodiment, and as such, a detailed description is omitted herein. Note that, in the case that switch810is OFF, in S503, when detecting the object, the power transmission apparatus801may complete the detection processing and the processing proceeds to S402.

With this configuration, the power transmission apparatus801can select either a mode that immediately executes authentication processing or a mode that reduces unnecessary authentication processing. Therefore, convenience of a user can be improved.

Other Embodiments

In the above embodiments, it has been described that the power reception apparatus is placed on the power transmission apparatus and then the wireless power transmission is performed. However, when there is a spatial distance between the power reception apparatus and the power transmission apparatus, the wireless power transmission may be performed. For example, the above embodiments can be applied to wireless power transmission in a non-contact state between an electric vehicle as the power reception apparatus and the power transmission apparatus built in a floor surface or a road surface.

In the above embodiments, it has been described that when the object is detected at each of the plurality of consecutive times of the power transmission for detection, the authentication processing is performed to the object. However, without detection of each of the plurality of consecutive times of the power transmission for detection, for example, when the object is detected every other time the power transmission for detection is performed during a predetermined period, the authentication processing may be also performed to the object. Alternatively, the authentication processing may be performed to the object detected predetermined times or more, for example, seven or more times out of ten, in the power transmission for detection during the predetermined period. Aspects of the present invention can be performed as follows. A program that implements a function or more in the above embodiments can be supplied to a system or an apparatus through a network or a recording medium, and a processor or more in a computer of the apparatus or the system reads and executes the program. Alternatively, a circuit that implements a function or more (for example, ASIC) can perform aspects of the present invention.

While aspects of the present invention have been described with reference to exemplary embodiments, it is to be understood that these exemplary embodiments are not seen to be limiting. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2014-249444, filed Dec. 9, 2014, which is hereby incorporated by reference herein in its entirety.