JP2000037046A - Power supply unit and loading device used for non- contact power supply, and detecting method for loading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply unit and a loading device used for non- contact power supply, and a detecting method for loading device which have no effects on another loading device and can prevent generation of wasteful power consumption due to erroneous detection. SOLUTION: This power supply unit and the loading device used for non- contact power supply, and a detecting method for the loading device are provided with a first step which transmits a detection signal from the coil 103 of a power supply unit 100, a second step which receives the detection signal transmitted from the first step by the coil 201 of a loading device 200, a third step which transmits the response signal to the detected signal received by the second step from the light emitting diode 207 of a loading device 201, a fourth step which receives the response signal transmitted from the third step by the photoelectric converting element 106 of the power supply unit 100, and a fifth step which compares the response signal received by the fourth step and the detected signal transmitted by the first step with each other to detect the presence of the loading device 200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, a load device, and a load device detection method used for non-contact power supply for supplying power from a power supply device to a load device in a non-contact manner.

[0002]

2. Description of the Related Art In a power supply device for supplying power to a load device in a non-contact manner, power transmission using electromagnetic waves is widely used because of its superior transmission efficiency. In power transmission by electromagnetic waves, as the distance between the power transmitting side and the power receiving side becomes longer, the electromagnetic coupling becomes weaker, and the received power is significantly attenuated. For this reason, when the distance between them is so large that the power transmission is difficult, the power transmission is stopped by the switch mechanism of the power supply device in order to prevent meaningless power release. As the above-mentioned switch mechanism, a switch directly operated by a person, a micro switch or a pressure switch for detecting contact with a load device, or the like is used.

A non-contact power supply device in which a power supply device does not contact a load device and a power supply device does not contact a person at the same time is difficult to control power transmission based on detection of a load device and operation of a person. It is general practice that the power supply always keeps transmitting power even when there is no load device within the transmission range. A non-contact power supply device in which a power supply device does not contact a load device and a power supply device does not contact a person at the same time has a problem that meaningless power transmission occurs. In order to solve the above-mentioned problem of meaningless power transmission, the above-mentioned power supply device side detects the presence of the receiving side in a non-contact manner, and performs power transmission only when the receiving side is in a range where power transmission is possible. Means are required. As such a detecting means, there is a detecting means provided with a permanent magnet on the receiver side and a magnetic switch on the power transmitting side. A measure is taken to supply power only while the permanent magnet turns on the magnetic switch. As a power supply system including the load device detecting means, for example, Japanese Unexamined Patent Application Publication No.
No. 30 is known.

FIG. 9 shows a power supply system including a conventional load device detecting means. In the figure, 1 is a power supply device, 2
Is an electronic circuit board, 3 is an electronic circuit, 4 is a magnetic switch, 5
Denotes a coil, 10 denotes a load device, 11 denotes an electronic circuit, 12 denotes an electronic circuit board, 13 denotes a permanent magnet, and 14 denotes a coil. In order to supply electric power to the load device 10, the electric power can be supplied when the load device 10 is set on the power supply device 1 as shown in FIG.

Next, the operation will be described. When the load device 10 is set on the power supply device 1, the magnetic switch 4 of the power supply device 1 is turned on by the permanent magnet 13 provided in the load device 10, and the electronic circuit 3 mounted on the electronic circuit board 2 is turned on.
Operates to generate an AC magnetic field from the coil 5, and the AC magnetic field penetrates the coil 14 of the load device 10 to generate an AC voltage, which is supplied to the electronic circuit 11 mounted on the electronic circuit board 12. Is done. When the load device 10 is removed from the power supply device 1, the magnetic switch 4 is turned off.
The electronic circuit 3 does not operate and does not consume power.

[0006]

However, in the conventional non-contact power supply device in which the power supply device 1 and the load device 10 do not come into contact with each other and the power supply device 1 does not come into contact with a person at the same time,
Since the magnetic field is emitted from the permanent magnet 13 of the load device 10 to the outside, the external device may be adversely affected. In particular, when a card-type portable device is considered as the load device 10, since it is stored in the same place as another magnetic card, the recorded contents of the magnetic card may be changed or lost due to close contact, which may cause trouble. .

The magnetic switch 4 of the power supply device 1
When a magnetic object is brought close to it, the magnetic switch 4
Is turned on, and there is a problem that meaningless electromagnetic energy emission into the space occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a power supply device and a load device used for non-contact power supply that do not adversely affect other load devices and that does not generate useless power consumption due to erroneous detection. An object of the present invention is to provide a load device detection method.

[0009]

In order to achieve the above object, a power supply device of the present invention emits an AC magnetic field to a load device having a receiving coil for obtaining power from an AC magnetic field by electromagnetic induction. A radiation coil that supplies power by contact;
Detection signal transmitting means for transmitting a detection signal for detecting the presence of the load device, response signal receiving means for receiving a response signal of the load device to the detection signal, and transmitting the detection signal to the detection signal transmitting means. A function of transmitting, a function of comparing the transmitted detection signal and the received response signal to detect the presence of the load device, and continuously radiating an alternating magnetic field from the radiation coil only when the presence of the load device is detected And control means having a function of causing the load device to supply electric power.

[0010] In the power supply apparatus according to the present invention, the detection signal transmitting means is the radiation coil, and the detection signal is an alternating magnetic field radiated from the radiation coil.

Further, the power supply device of the present invention is characterized in that the detection signal is an alternating magnetic field of a predetermined pulse train radiated from the radiation coil. Further, in the power supply device according to the present invention, the response signal receiving means is a light receiving means for receiving an optical signal emitted from the load device.

According to the present invention, there is provided a load device used for non-contact power supply having a receiving coil for obtaining electric power by electromagnetic induction from an AC magnetic field radiated from a radiation coil of a power supply device. It is characterized by comprising detection signal receiving means for receiving a signal, and response signal transmitting means for transmitting a response signal to the received detection signal.

In the load device according to the present invention, the detection signal is an AC magnetic field radiated from a radiation coil of a power supply device, and the detection signal receiving means is the receiving coil.

Further, in the load device according to the present invention, the response signal transmitting means is a light emitting means. Further, the load device of the present invention is characterized in that the light emitting means is a light emitting means which emits light only when a current is generated in the receiving coil by an AC magnetic field radiated from a radiating coil of a power supply device. It is.

Further, in the load device detection method according to the present invention, a first step of transmitting a detection signal for detecting the presence of the load device from a detection signal transmitting means of the power supply device, and the transmission of the detection signal in the first step. A second step of receiving the detected signal by the detection signal receiving means of the load device, a third step of transmitting a response signal to the detection signal received in the second step from the response signal transmitting means of the load device, A fourth step in which the response signal transmitted in the third step is received by a response signal receiving unit of the power supply device; a response signal received in the fourth step; and a detection signal transmitted in the first step. And a fifth step of detecting the presence of the load device by comparing

Further, in the load device detection method according to the present invention, the power supply device emits an alternating magnetic field of a predetermined pulse train from the radiating coil, and the load device operates only when a current is generated in the receiving coil by the alternating magnetic field of the pulse train. The power supply device receives light and emits response light of the load device, and detects the presence of the load device.

Further, the load device detection method of the present invention includes a first step of radiating an AC magnetic field of a first pulse train from the radiation coil and a step of detecting an output signal from the light receiving means. Radiating an alternating magnetic field of a second pulse train different from the first pulse train from the radiation coil, detecting an output signal from the light receiving means, detecting the output signal and the second pulse train And a third step of detecting an output signal from the light receiving means while continuously radiating an AC magnetic field from the radiation coil, wherein the first step comprises: When the output signal from the light receiving means in response to the first pulse train is detected in the process, the process proceeds to the second process, and the output from the light receiving device in response to the first pulse train is detected. When no signal is detected, the first step is continued. When an output signal from the light receiving means in response to the second pulse train is detected in the second step, the second step is repeated a predetermined number of times. When an output signal responsive to the second pulse train is detected at each repetition, it is determined that a load device is present, and the process proceeds to the third step, and an output signal responsive to the second pulse train is not detected. In this case, it is determined that the load device is not present, and the process immediately returns to the first step. If the output signal from the light receiving unit is not detected in the third step, it is determined that the load device is not present. Returning to the first step immediately.

Further, in the load device detecting method according to the present invention, the first pulse train has a smaller magnetic field emission period than a magnetic field non-emission period. In the load detection method according to the present invention, the second pulse train is a frequency modulation pulse train, a pulse position modulation pulse train, or an encoded code pulse train.

According to the present invention, power transmission is performed only when the power supply device receives a response signal by light from the load device. Another feature is that a malfunction is caused by external light by modulating the power transmission request signal by light.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration explanatory view showing an embodiment of the present invention. 100 is a power supply device, 1
03 is a radiation coil, 106 is a photoelectric conversion element, 200 is a load device, 201 is a receiving coil, 207 is a light emitting element, 22
0 is disturbance light. The power supply device 100 is a load device 20
Radiating coil 10 for supplying electric power to non-contact
3 and a photoelectric conversion element 106 serving as a response signal receiving unit for receiving a response signal by light from the load device 200. The load device 200 includes a receiving coil 201 for receiving power from the power supply device 100 and a power supply device 100. A light emitting element 207 as a response signal transmitting means for transmitting a response signal is provided.

Next, the operation will be described. The non-contact detection of the load device 200 is performed by the coil 1 serving also as a detection signal transmitting unit.
After emitting an AC magnetic field, which is a detection signal, from 03, it can be realized by checking for the presence or absence of a response signal due to light. That is, the coil 201 serving also as the detection signal receiving means of the load device 200 receives the power corresponding to the detection signal, and transmits a response signal by light using the light emitting element 207. Power supply device 10
0, the photoelectric conversion element 1
06, a response signal can be detected, and when the load device 200 is out of the power supply range of the power supply device 100, the load device 200 does not obtain power reception energy according to the detection signal or transmits a response signal. The response signal does not return to the power supply device 100 because there is not enough energy to do so. However, in this state, there is a possibility that the energy required for the detection of the load device 200 is large because the AC magnetic field which is the detection signal is constantly emitted, and that the response signal due to the disturbance light 220 may be erroneously received.

Therefore, the power supply device 100 is provided with three operation modes, that is, a load device detection mode, a load device identification mode, and a power transmission mode. The operation in the three modes will be described below.

The load device detection mode is a mode for detecting the load device 200, and detects the presence of the load device 200 while minimizing power consumption. The average power consumption can be reduced by intermittently radiating the AC magnetic field from the coil 103. FIG. 2 shows the timing of the AC magnetic field emission period and the AC magnetic field non-emission period. The time interval of the AC magnetic field emission is the sum of the AC magnetic field emission period and the AC magnetic field non-emission period, and is the frequency of detection of the load device 200.
It can be about one second. Since the above-described AC magnetic field emission time is proportional to the amount of magnetic field emission energy, the load device 20
It is determined according to the setting of the 0 detection range. For example, if the detection range is about 2 mm, the magnetic field emission time can be a value of about 1 microsecond. If the magnetic field emission time is set to 1 microsecond every other second, the average power consumption can be reduced to one millionth compared to the case where the magnetic field is constantly emitted. When a response signal by light is received during the response signal receiving period, the operation mode is shifted to a load device identification mode described later.

In the load device identification mode, the load device 1 is detected after the load device 100 is detected in the load device detection mode.
00 is a mode for checking whether or not 00 is genuine while minimizing power consumption. By changing the AC magnetic field emission interval from the coil 103 to a frequency-modulated pulse train, a pulse position-modulated pulse train, or a coded code pulse train, erroneous recognition is performed by applying frequency modulation or pulse position modulation to a response signal by light. Preventing. That is,
When the power supply device 100 confirms that the load device 200 is genuine, the information obtained by changing the magnetic field emission interval by the recognition code and demodulating the response signal by the light returned from the load device 200 is the information described above. If it matches the recognition code, the load device 200 determines that it is genuine. Also, the recognition operation is performed not twice but twice or more,
By confirming the coincidence with the code, the confirmation ability can be enhanced.

FIGS. 3 and 4 show an example of the operation in the load device identification mode. FIGS. 3A and 3B show an example of a code definition, and FIG. 3A shows a code definition of “1”, where the magnetic field emission period T and the magnetic field non-emission period T are equal. FIG. 3B shows a code definition of “0”, in which the magnetic field emission period T is shorter than the magnetic field non-emission period 2T. FIG.
Indicates the timing when the code "A" is transmitted by the magnetic field. That is, the power supply device 100 encodes the uppercase letter “A” of the alphabet using an ASCII code,
Pulse position modulation is performed as a binary data string of bits “01000001” and transmitted by a magnetic field. A response signal is received from the light emitting element of the load device 200 by light emission timing, and the demodulated data string “01000001” is decoded by an ASCII code. As a result, the uppercase letter “A” of the alphabet is obtained, and the transmission data and the reception data match, indicating that the load device is determined to be genuine. In the above operation, in order to facilitate decoding, a reader unit indicating the head of the data string may be added before the data string transmitted by the magnetic field. When it is determined that the load device 200 is genuine in the load device identification mode, the process proceeds to a power transmission mode described later. If it is determined that the load device 200 is a fake, the process proceeds to the load device detection mode.

The power transmission mode is a mode in which power transmission to the load device 100 is executed after it is determined that the object detected in the load device identification mode is the real load device 100. The AC magnetic field is continuously transmitted while confirming the presence or absence of a response signal by light. When the load device 200 moves out of the power supply range, the response signal by light does not return to the power supply device 100. Therefore, the power supply is stopped, and the mode shifts to the load device detection mode.

The photoelectric conversion element 106 receives disturbance light in addition to a response signal due to light. The disturbance light includes static light such as sunlight and dynamic light such as a fluorescent light, and the wavelength of light is widely distributed. The influence of the disturbance light on the electric output signal of the photoelectric conversion element 106 appears as noise of a DC component and an AC component. For this reason, it is necessary to devise to increase the S / N ratio of the electric output signal. In order to minimize the adverse effect of the disturbance light, an optical filter that cuts light other than the emission wavelength of the light emitting element 207 is attached to the light receiving surface of the photoelectric conversion element 106, and the emission wavelength of the light emitting element 207 is set to a wavelength that is less affected by the disturbance light. By selecting, the S / N ratio of the electric output signal of the photoelectric conversion element 106 can be improved also in this device.

FIG. 5 is an explanatory diagram showing a specific example of FIG. 100 is a power supply device, 101 is a power supply line, 10
2 is a capacitor, 103 is a coil, 104 is a semiconductor switch, 105 is a control circuit, 106 is a photoelectric conversion element, 20
0 is a load device, 201 is a coil, 202 is a capacitor,
203 is a diode, 204 is a capacitor, 205 is a resistor, 207 is a light emitting element, and 208 is a data processing circuit. The power supply line 101 is connected in series with the coil 103 and the semiconductor switch 104, and the capacitor 102 is connected to the coil 10
3, the switch control terminal of the semiconductor switch 104 is connected to the control circuit 105, and the photoelectric conversion element 106 is connected to the control circuit 105. The coil 201 is connected in series with the diode 203 and the capacitor 204,
Numeral 02 is connected in parallel to the coil 201, the resistor 205 and the light emitting element 207 connected in series are connected in parallel to the coil 201, and the data processing circuit 208 is connected in parallel to the capacitor 204. Here, the connection direction of the diode 203 is connected in the direction in which the semiconductor switch 104 conducts when the semiconductor switch 104 is on. The connection direction of the light emitting element 207 is
Are connected in the direction in which light is emitted when is turned on. Control circuit 1
As 05, for example, an arithmetic processing circuit as shown in FIG. 6 can be used. 107 is an RO for storing programs
M, 108 are timers, 109 is CPU, 110 is RA
M and 111 are input / output interfaces.

These operations are the same as those in FIG.
As the photoelectric conversion element 106, for example, a photodiode, a phototransistor, and a light receiving module can be used. As the light-emitting element 207, a light-emitting diode (LED) can be used.

The detection signal transmitting means may be provided separately from the radiation coil. FIG. 7 is a flowchart illustrating an example of the load device detection method according to the present invention. That is, in the first step, a detection signal for detecting the presence of the load device is transmitted from the detection signal transmission means of the power supply device. In the second step, the detection signal transmitted in the first step is received by the detection signal receiving means of the load device. In the third step, a response signal to the detection signal received in the second step is transmitted from the response signal transmitting means of the load device. In the fourth step, the response signal transmitted in the third step is received by the response signal receiving means of the power supply device. In a fifth step, the response signal received in the fourth step and the first
The presence of the load device is detected by comparing the detection signals transmitted in the step.

FIGS. 8A and 8B show another example of the load detecting method according to the present invention, wherein FIG. 8A is a sectional view and FIG. 8B is a plan view.
That is, the radiating coil 103 is provided in the center of the power supply device 100, and the first light emitting unit 301 and the second light emitting unit 302 are provided close to one side of the power supply device 100, and The first light receiving unit 401 and the second light emitting unit 301 are separated from the first light emitting unit 301 and the second light emitting unit 302 by a predetermined distance.
Are provided adjacent to each other. A third light emitting unit 303 and a fourth light emitting unit 304 are provided close to each other on the other side of the power supply device 100 and are separated from the third light emitting unit 303 and the fourth light emitting unit 304 by a predetermined distance. Third
The light receiving unit 403 and the fourth light receiving unit 404 are provided close to each other. As each of the light emitting units 301 to 304, for example, a light emitting diode (LED) is used.
As 01 to 404, for example, a photodiode, a phototransistor, a light receiving module, or the like is used. The light emitting units 301 to 304 and the light receiving units 401 to 404 are provided on an electronic circuit board 500 on which an electronic circuit is formed. The receiving coil 20 is located at the center of the load device 200.
1, two optical fibers 601 and 602 are provided on one side of the load device 200, and two optical fibers 603 and 604 are provided on the other side of the load device 200. One end of the optical fiber 601 is provided so as to correspond to the first light emitting unit 301, and the other end of the optical fiber 601 is provided so as to correspond to the first light receiving unit 401. One end of the optical fiber 602 is provided so as to correspond to the second light emitting unit 302, and the other end of the optical fiber 602 is
Are provided so as to correspond to the light-receiving unit 402 of FIG. One end of the optical fiber 603 is provided so as to correspond to the third light emitting unit 303, and the other end of the optical fiber 603 is provided so as to correspond to the third light receiving unit 403. Optical fiber 60
4 is provided so as to correspond to the fourth light emitting unit 304, and the other end of the optical fiber 604 is connected to the fourth light receiving unit 40.
4 is provided.

That is, the first light emitting portion 301 and the second light emitting portion 302 emit light while blinking alternately,
The light emitting unit 303 and the fourth light emitting unit 304 emit light while blinking alternately. Thus, the first light receiving unit 401 and the second
Of the first light emitting unit 301 and the second light emitting unit 302 detects alternately blinking light through the optical fiber, or the third light receiving unit 403 and the fourth light receiving unit 4
04 detects the alternately blinking light from the third light emitting unit 303 and the fourth light emitting unit 304 through the optical fiber, determines that the load device 200 is within the power supply range, and An AC magnetic field is generated from the radiation coil 103 to supply power to the receiving coil 201 of the load device 200. On the other hand, the first light receiving unit 401 and the second light receiving unit 402 are the first light emitting unit 301 and the second light emitting unit 30.
The third light-receiving unit 403 and the fourth light-receiving unit 404 do not detect the alternately blinking light from
If no alternately blinking light from the third and fourth light emitting units 304 is detected, it is determined that the load device 200 is outside the power supply range, and the radiation coil 1 of the power supply device 100 is determined.
03 does not generate an AC magnetic field.

The disturbance light includes static light such as sunlight and dynamic light such as a fluorescent lamp, and the wavelengths of the light are widely distributed. By emitting light while blinking, the influence of disturbance light can be prevented. 2
The light emitting units may emit light with different wavelengths. In this case, it is effective to select a wavelength that is less affected by disturbance light. Further, by providing optical fibers on both sides of the load device 200, the influence of the orientation of the load device 200 can be reduced.

[0034]

As described above, according to the present invention, when a load device is detected, a magnetic field is radiated from a coil intermittently and a response signal from the load device is received by a power supply device. Only, by adopting a configuration that performs power transmission,
The average power consumption of the power supply device can be significantly reduced.

Further, it is possible to detect a load device which does not adversely affect the outside by using light for the response signal. Further, upon detection of a load device, a data sequence is transmitted by modulating the magnetic field radiation, a response signal by the light is demodulated and decoded, and a match between the transmitted data sequence and the received data sequence is checked to determine whether a fluorescent lamp or the like is used. The influence of DC disturbance light can be removed, and malfunction due to disturbance light can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of the power supply device according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of a code definition according to the present invention.

FIG. 4 is an explanatory diagram showing an example when a code is transmitted by a magnetic field according to the present invention.

FIG. 5 is a configuration explanatory view showing a specific example of an embodiment of the present invention.

FIG. 6 is a configuration explanatory view showing an example of a control circuit of the power supply device according to the present invention.

FIG. 7 is a flowchart illustrating an example of a load device detection method according to the present invention.

FIG. 8 is a sectional view and a plan view showing another embodiment of the present invention.

FIG. 9 is an explanatory diagram of a configuration of a system including a conventional power supply device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 power supply device 2 electronic circuit board 3 electronic circuit
4 magnetic switch, 5 coil, 10 load device, 11
... Electronic circuit, 12 ... Electronic circuit board, 13 ... Permanent magnet, 1
Reference Signs List 4 coil, 100 power supply device, 101 power supply line, 102 capacitor, 103 coil, 104 semiconductor switch, 105 control circuit, 106 photoelectric conversion element, 107 ROM for program storage, 108 timer 109, CPU, 110, RAM, 111, input / output interface, 200, load device, 201, coil, 202, capacitor, 203, diode, 204
... capacitor, 205 ... resistor, 207 ... light emitting element, 20
7 ... light emitting element, 208 ... data processing circuit, 220 ... disturbance light.

Claims (13)

[Claims] A radiation coil for radiating an AC magnetic field to a load device having a receiving coil for obtaining electric power from an AC magnetic field by electromagnetic induction and supplying electric power in a non-contact manner, and for detecting the presence of the load device Detection signal transmitting means for transmitting the detection signal, response signal receiving means for receiving a response signal of the load device to the detection signal, a function for causing the detection signal transmitting means to transmit the detection signal, and the transmitted detection A function of comparing the signal with the received response signal to detect the presence of the load device, and continuously radiating an AC magnetic field from the radiation coil only when the presence of the load device is detected, thereby supplying power to the load device. A power supply device used for non-contact power supply, comprising: control means having a function. 2. The power supply device according to claim 1, wherein the detection signal transmitting means is the radiation coil, and the detection signal is an AC magnetic field radiated from the radiation coil. . 3. The power supply device according to claim 2, wherein the detection signal is an AC magnetic field of a predetermined pulse train radiated from the radiation coil. 4. The power supply device according to claim 1, wherein said response signal receiving means is a light receiving means for receiving an optical signal emitted from a load device. 5. A load device having a receiving coil for obtaining power by electromagnetic induction from an alternating magnetic field radiated from a radiating coil of a power supply device, the load device being used for non-contact power supply, receiving a detection signal transmitted by the power supply device. And a response signal transmitting means for transmitting a response signal to the received detection signal. 6. The non-contact power supply according to claim 5, wherein the detection signal is an AC magnetic field radiated from a radiation coil of a power supply device, and the detection signal receiving unit is the reception coil. Load device. 7. The load device according to claim 5, wherein the response signal transmitting unit is a light emitting unit. 8. The light emitting device according to claim 7, wherein the light emitting device emits light only when a current is generated in the receiving coil by an AC magnetic field radiated from a radiating coil of a power supply device. Load device used for non-contact power supply. 9. A first method for transmitting a detection signal for detecting the presence of a load device from a detection signal transmitting means of a power supply device.
And a second step in which the detection signal transmitted in the first step is received by a detection signal receiving unit of the load device; and a response signal to the detection signal received in the second step is a response of the load device. A third step of transmitting from the signal transmitting means, a fourth step of receiving the response signal transmitted in the third step by the response signal receiving means of the power supply device, and a response received in the fourth step A fifth step of detecting the presence of a load device by comparing the signal with the detection signal transmitted in the first step. 10. A power supply device emits an alternating magnetic field of a predetermined pulse train from a radiation coil, and a load device emits light only when a current is generated in a receiving coil due to the alternating magnetic field of the pulse train. A load device detecting method used for non-contact power supply, wherein light emission is received by a light receiving unit of a power supply device to detect the presence of the load device. 11. A first step comprising: radiating an alternating magnetic field of a first pulse train from the radiation coil; detecting an output signal from the light receiving means; Second pulse different from the pulse train
Irradiating an alternating magnetic field of a pulse train of the following, detecting an output signal from the light receiving means, and comparing the detected output signal with the second pulse train, a second process comprising: A third step of detecting an output signal from the light receiving means while continuously radiating an AC magnetic field from the radiating coil, wherein the third step is a step from the light receiving means responding to the first pulse train in the first step. If an output signal is detected, the process proceeds to the second step. If an output signal from the light receiving unit in response to the first pulse train is not detected, the first step is continued. When an output signal from the light receiving means in response to the second pulse train is detected, the second process is repeated a predetermined number of times, and an output signal in response to the second pulse train is detected each time it is repeated. In this case, it is determined that the load device is present, and the process proceeds to the third step. If the output signal corresponding to the second pulse train is not detected, it is determined that the load device is not present, and the process immediately proceeds to the first process. 11. The method according to claim 10, wherein when the output signal from the light receiving means is no longer detected in the third step, it is determined that the load device is no longer present, and the process immediately returns to the first step. A load device detection method used for non-contact power supply. 12. The first pulse train according to claim 1, wherein the magnetic field emission period is shorter than the magnetic field non-emission period.
2. A method for detecting a load device used for non-contact power supply according to claim 1. 13. The method according to claim 11, wherein the second pulse train is a frequency modulation pulse train, a pulse position modulation pulse train, or an encoded code pulse train.