Patent Description:
Light pulses can be used to provide a physiological effect on a human or animal body. For example light pulses can be applied to parts of the body to provide physiological effects on the skin or tissue below the skin. However, at present, light pulse therapy devices require a dedicated power source or power supply, which makes light therapy devices large and bulky.

Pulsed electromagnetic fields can also be used to provide physiological effects on the body. For example, pulsed electromagnetic fields can be used to provide therapeutic benefits, such as treating ailments like joint and muscle pain, and assisting with the healing of broken bones and fractures.

It is desirable to develop a system that overcomes or mitigates the problems associated with light pulse therapy devices, whilst improving the physiological effects and therapeutic benefits achievable with light pulses and pulsed electromagnetic fields. Exemplary systems for light pulse generation are described in publications <CIT> and <CIT>.

For explanatory purposes other exemplary embodiments, which do not form part of the invention, are additionally described in the present disclosure.

In a first aspect of the present disclosure, there is provided a system comprising:.

wherein the light generating unit is arranged to receive at least some of the induced first current and emit a light pulse having an intensity proportional to the received current.

Advantageously, the second device can emit a light pulse without requiring a separate power supply or power source. Rather, the second device is able to emit light using energy transferred from the pulsed EMF device via the EMF pulse. Furthermore, the current induced in the second device will naturally have a similar waveform or shape to the EMF pulse. As such, in exemplary embodiments, the induced current and consequently the light pulse, will be synchronised with the EMF pulse. In particular, the light pulse will comprise peaks in intensity that are time-synchronised with energy peaks of the EMF pulse. The synchronisation between the EMF pulse and light pulse has been found to enhance the respective physiological effects caused by the EMF pulse and the light pulse when the EMF pulse and the light pulse are provided to parts of a human or animal body.

In exemplary embodiments, the EMF pulse comprises a decaying sequence of electromagnetic (EM) oscillations.

Advantageously, this type of EMF pulse has been found to more effectively provide a physiological effect on the body.

In exemplary embodiments, the pulsed EMF device comprises an inductor configured to emit the EMF pulse, and the second device comprises means for mounting the second device to the pulsed EMF device such that the coil loop of the second device is inductively coupled with the inductor when the second device is mounted to the pulsed EMF device.

Advantageously, the pulsed EMF device and the second device can be provided as a combined unit to provide both a pulsed EMF and light pulses to the body. For example, the pulsed EMF device and the second device can comprise separate housings, and the housing of the second device can detachably mount to the housing of the pulsed EMF device as a modular attachment. This gives the user or operator the choice of providing a pulsed EMF treatment or a combination of a pulsed EMF and light pulses. Furthermore, the inductive coupling between the inductor and the coil loop provides for efficient means of energy transfer between the pulsed EMF device and the second device, in the absence of a power source or a power supply in the second device.

In exemplary embodiments, the mounting means is for mounting the second device to the inductor of the pulsed EMF device such that the coil loop of the second device is inductively coupled with the inductor when the second device is mounted to the inductor.

Advantageously, this arrangement has been found to further improve the efficiency of energy transfer between the pulsed EMF device and the second device given the closer proximity between the coil loop and the inductor. Furthermore, the pulsed EMF device and the second device can be provided as a single unit in a more compact form. For example, both the second device and the pulsed EMF device can be contained within a unitary common housing in which the second device is mounted to the inductor of the pulsed EMF device. Alternatively, the pulsed EMF device and the second device can be comprised in separate housings, but the inductor can be external to the housing of the pulsed EMF device to enable the second device to mount to the inductor.

In exemplary embodiments, the second device further comprises a rectifier coupled between the coil loop and the light generating unit, and the rectifier is configured to at least partly rectify the induced current.

Advantageously, rectifying the induced current has been found to improve the safety of the second device and prevent damage to the components of the light generating unit.

In exemplary embodiments, the second device further comprises an interface circuit coupled between the rectifier and the light generating unit, and the interface circuit is configured to condition the waveform of the induced current and output a conditioned current, wherein the light generating unit receives the conditioned current.

Advantageously, controlling the waveform of the induced current will in turn control the light output of the light generating unit. As such, the interface circuit can be used to control or tune how the light generating unit responds to the induced current by conditioning the induced current. It will be appreciated that in some exemplary embodiments, the rectifier may be omitted and the interface circuit may be coupled between the coil loop and the light generating unit.

In exemplary embodiments, the interface circuit comprises:.

Consequently, the light pulse will comprise a combination of a low frequency component (a smooth pulse over the duration of the EMF pulse) and a high frequency component (a sequence of peaks synchronised with or corresponding to oscillations of the EMF pulse). Advantageously, the high frequency component has been found to contribute to providing an enhanced physiological effect in combination with the EMF pulse. By also including the low frequency component, the light pulse will be observed by the human eye as a single "blink". Therefore, the low frequency component may protect the human eye from the sharp flashes caused by the high frequency component, thereby improving the safety of the system. It will be appreciated that in some exemplary embodiments, the rectifier may be omitted. The low pass filter may be coupled between the coil loop and the light generating unit. Furthermore the resistive path may be between the coil loop and the light generating unit in parallel with the low pass filter.

Advantageously, values of the first resistor and the capacitor can be chosen to set the cut-off frequency of the low-pass filter so that the low pass filter outputs the desired low-frequency component. Furthermore, the value of the second resistor can be chosen to determine the overall current output of the low-pass filter, and thus the overall brightness of the light pulse. Furthermore, the value of the third resistor can be chosen to determine the amplitude or brightness of the high-frequency peaks.

In exemplary embodiments, the light generating unit comprises at least one light-emitting diode (LED).

Advantageously, the light generating unit can be implemented cost effectively whilst taking up a smaller circuit area.

In exemplary embodiments, the LED is configured to emit infrared or red light. Advantageously, infrared or red visible light has been found to enhance the physiological effect provided by the light pulse.

According to the invention, the second device comprises a second coil loop electrically coupled to the light generating unit. The second coil loop is configured to induce a second current in response to the EMF pulse. The light generating unit is arranged to receive at least some of the first current and the second current. Furthermore, the first coil loop is in a first plane and the second coil loop is in a second plane that is different to the first plane.

Advantageously, optimal power transfer between the coil looped inductor and the second device can be maintained when the coil looped inductor is angled relative the second device. In particular, current from both the first and the second coil loops can contribute to powering the light therapy device when the coil looped inductor is not at an optimal orientation or position relative to the light therapy device.

In exemplary embodiments, the first plane and the second plane intersect.

Advantageously, the first plane is angled relative to the second plane. This enables improved power transfer between the coil looped inductor and the second device for a range of relative angles and positions between the coil looped inductor and the coil loops of the second device.

In exemplary embodiments, the first plane and the second plane are substantially orthogonal or perpendicular to one another.

Advantageously, an approximate <NUM> degree angle may be the most optimal angle between the planes for improved power transfer during use.

In exemplary embodiments, the rectifier is a first rectifier.

In exemplary embodiments, the second device further comprises a second rectifier coupled between the second coil loop and the light generating unit. The second rectifier is configured to at least partly rectify the second current.

Advantageously, the second current is rectified which further improves the safety of the second device whilst preventing damage to the components of the light generating unit.

In exemplary embodiments, the interface circuit is configured to condition the waveform of a sum of the first current and the second current.

Advantageously, the interface circuit is used to control or tune how the light generating unit responds to the sum of the induced currents by conditioning the sum of the currents.

In exemplary embodiments, the second device comprises a third coil loop electrically coupled to the light generating unit. The third coil loop is configured to induce a third current in response to the EMF pulse, and the light generating unit is arranged to receive at least some of the first current, the second current and the third current. The third coil loop is in a third plane different to the first plane and the second plane. Optionally, the third plane intersects with the first plane and the second plane. Optionally, the first second and third planes are orthogonal to each other.

Advantageously, the third coil loop can further improve the angular independence of the light therapy device. For example, the light therapy device may achieve improved power transfer from the pulsed EMF device for a wider range of orientations and positions of the coil looped inductor.

In exemplary embodiments, the second device comprises means for attaching the second device to a part of a human or an animal body.

Advantageously, the second device can be used as a wearable device. For example, the second device can be secured at a predetermined position on the body part that is to receive light therapy and/or combined light and pulsed EMF therapy.

In exemplary embodiments, the pulsed EMF device further comprises:.

Advantageously, unlike other pulsed electromagnetic field therapy devices, the pulsed electromagnetic field therapy device has a parallel resonant circuit which does not require a switch (such as a semiconductor or spark gap switch) to be an integral component of the parallel resonant circuit to selectively power the parallel resonant circuit. By having a switch external to the parallel resonant circuit instead, when current flows around the parallel resonant circuit, it does not pass through a switch on each pass which would unnecessarily dissipate energy stored in the parallel resonant circuit through resistance losses in the switch. Moreover, suitable high voltage switches which can be used as a component of the parallel resonant circuit of a pulsed electromagnetic field therapy device are expensive. Therefore, by having a switch external to the parallel resonant circuit rather than as a component of the parallel resonant circuit, manufacturing costs are significantly reduced and resistance losses from the switch are eliminated. Without these resistance losses from the switch, the decay time of the pulsed electromagnetic field generated by the parallel resonant circuit is greatly increased, thereby increasing the time period over which a physiological effect is generated. Moreover, an increased decay time of the pulsed electromagnetic field allows for increased power transfer to the second device. Also, the desired current required to obtain a desired time period over which a physiological effect is achieved is much less.

Moreover, by having a switch external to the parallel resonant circuit rather than as a component of the parallel resonant circuit, it is possible to ramp the current over a period of time (the current ramping period). In contrast, other pulsed electromagnetic field therapy devices with a switch as a component of the parallel resonant circuit cause charge from the pre-charged capacitor to be dumped nearly instantaneously into the resonant circuit when the switch in the parallel resonant circuit is closed. The high voltages which are necessary to achieve the high currents needed to overcome resistance losses in the high voltage switch, cause a surge of current in the resonant circuit as soon as the switch is closed. This sudden surge in current in the resonant circuit has been found to result in reflections from the high voltage switch (which intrinsically lacks impedance matching with the resonant circuit) resulting in significant voltage and current spikes and electromagnetic interference which can be harmful to nearby electrical devices. In contrast, increasing the current over the current ramping period, which is made possible by the switchless parallel resonant circuit of the exemplary embodiment, reduces noise and interference caused by the pulsed electromagnetic field therapy device, which helps the pulsed electromagnetic field therapy device meet regulatory requirements, such as regulations regarding electromagnetic interference. For example, the pulsed electromagnetic field therapy device can be operated at lower frequencies than other devices, therefore preventing the pulsed electromagnetic field therapy device from interfering with other electronic devices such as the second device, or with radio communications networks. Additionally, a cleaner (e.g. less noisy) waveform of the pulsed electromagnetic field has been found to allow for improved and more efficient power transfer to the second device.

There is also described a method not forming part of the invention and comprising:.

receiving at least some of the induced current at a light generating unit electrically coupled to the coil loop; and
emitting a light pulse from the light generating unit in response to the received current, the light pulse having an intensity proportional to the received current.

In exemplary embodiments, the coil loop is inductively coupled to the inductor of the pulsed EMF device.

In exemplary embodiments, the method further comprises rectifying the induced current using a rectifier coupled in between the coil loop and the light generating unit.

In exemplary embodiments, the method further comprises conditioning the waveform of the induced current using an interface circuit coupled between the rectifier and the light generating unit, and receiving the conditioned current at the light generating unit.

In exemplary embodiments, conditioning the waveform of the induced current comprises low-pass filtering a portion of the induced current using a low pass filter coupled between the rectifier and the light generating unit, to generate a low frequency component of the conditioned current comprising a smooth pulse over the duration of the EMF pulse.

In exemplary embodiments, conditioning the waveform of the induced current comprises passing a portion of the induced current through a resistive path provided between the rectifier and the light generating unit in parallel with the low-pass filter, to generate a high frequency component of the conditioned current comprising a sequence of peaks synchronised with or corresponding to oscillations of the EMF pulse.

In exemplary embodiments, the amplitude or duration of the low frequency component is dependent on a value of one or more resistors of the low pass filter; and/or the amplitude of the high-frequency component is dependent on a value of a resistor in the resistive path.

In exemplary embodiments, the light pulse is emitted from at least one light-emitting diode (LED) of the light generating unit.

In exemplary embodiments, the light pulse is infrared or red light.

In exemplary embodiments, the coil loop is a first coil loop and the induced current is a first current.

In exemplary embodiments, the method further comprises: providing a second coil loop for inductively coupling to the inductor of the pulsed EMF device; inducing a second current in the second coil loop in response to the EMF pulse; and receiving at least some of the first current and the second current at the light generating unit, wherein the first coil loop is provided in a first plane and the second coil loop is provided in a second plane that is different to the first plane.

In exemplary embodiments, the method further comprises at least partly rectifying the second current using a second rectifier coupled in between the second coil loop and the light generating unit.

In exemplary embodiments, the method further comprises conditioning the waveform of a sum of the first current and the second current using an interface circuit coupled between the first and the second rectifiers and the light generating unit and receiving the conditioned current at the light generating unit.

In exemplary embodiments, the method further comprises providing a third coil loop for inductively coupling to the inductor of the pulsed EMF device. The third coil loop is induces a third current in response to the EMF pulse, and the light generating unit receives at least some of the first current, the second current and the third current. The third coil loop is in a third plane that is different to the first plane and the second plane. Optionally, the third plane intersects with the first plane and the second plane. Optionally, the first, second and third planes are orthogonal or perpendicular to one another.

In exemplary embodiments, the inductor is comprised in a switchless parallel resonant circuit, and wherein generating the EMF pulse comprises:.

Examples of the present disclosure are now described with reference to the accompanying drawings, in which:.

The present disclosure relates to a system that emits a pulsed electromagnetic field (EMF) to a part of the human or animal body (e.g. a limb or a joint), whilst simultaneously emitting a series of light pulses to a part of the body. In particular, the systems emits the light pulses using energy harvested from the pulsed EMF. The system can be provided as a single unit or device. The system incorporates a pulsed EMF therapy device and a light therapy device. The pulsed EMF device is configured to generate the pulsed EMF, whereby each pulse includes a sequence of damped sinusoidal electromagnetic oscillations. The pulsed EMF is emitted by a coil looped inductor of the pulsed EMF device. The coil looped inductor is arranged to be placed adjacent to or around a part of the body, for example, to produce a physiological effect on the body. Circuitry of the light therapy device is inductively or magnetically coupled to the coil looped inductor of the pulsed EMF device. As such, the pulsed EMF generated in the coil looped inductor causes currents and voltages to be induced in the circuitry of the light therapy device. The light therapy device comprises one or more light emitting diodes (LEDs) that are arranged to emit light in response to the induced currents and voltages. The LEDs are arranged to be placed adjacent to or around a part of the body to provide the emitted light to the body, for example, to also produce a physiological effect on the body.

Advantageously, the light therapy device can operate without the need for a separate power supply or power source, and instead uses energy transferred from the coil looped inductor via the pulsed EMF. In other words, the light therapy device is able to operate using energy harvested from the pulsed EMF emitted by the pulsed EMF device, without the need for a separate power source such as a battery, or connection to a mains electricity supply. As such, the light therapy device can be provided in a smaller and more compact form, for example in a combined unit with the pulsed EMF device, or as a separate wearable device. Furthermore, due to the inductive coupling, the waveforms of the currents and voltages induced in the light therapy device will be synchronised with the energy waveform of the pulsed EMF. This means that the light pulses emitted by the LEDs will have an intensity or brightness that is synchronised with the energy or power level of the pulsed EMF. Advantageously, the synchronisation between the light pulses and the pulsed EMF has been found to enhance the respective physiological effects provided by the light pulse and the pulsed EMF, especially where the light pulses and the pulsed EMF are provided to the same part of the body.

<FIG> shows a system <NUM> according to an example of the present disclosure. The system <NUM> comprises a pulsed electromagnetic field (PEMF) therapy device <NUM> and a light therapy device <NUM>. The PEMF therapy device <NUM> is configured to generate and emit a pulsed electromagnetic field (EMF) <NUM>. The light therapy device <NUM> is configured to emit light <NUM> in response to the pulsed EMF <NUM>. In particular, the light therapy device <NUM> is configured to convert the pulsed EMF <NUM> into electrical energy and generate the light <NUM> based on the electrical energy. Advantageously, the light therapy device <NUM> is able to emit the light <NUM> based on the pulsed EMF <NUM>, without requiring a separate power source or a power supply.

The PEMF device <NUM> comprises a coil looped inductor <NUM> and a current generating circuit <NUM>. The coil looped inductor <NUM> is electrically coupled to the current generating circuit <NUM>. The current generating circuit <NUM> is configured to generate and supply a current I<NUM> to the coil looped inductor <NUM>. The coil looped inductor <NUM> is configured to generate the pulsed EMF <NUM> in response to the current I<NUM>. The coil looped inductor <NUM> is arranged in the device <NUM> to be placed adjacent to or around a part of a human or animal body (e.g. a limb or joint), in order to provide the pulsed EMF to that part of the body and produce a physiological effect.

<FIG> illustrates an oscilloscope trace <NUM> showing the current I<NUM> as a function of time t. As shown, the current I<NUM> is an alternating current (AC) having a decaying sinusoidal shape. In other words, the current I<NUM> comprises a sequence of decaying or damped sinusoidal oscillations. The sequence of oscillations start at time t<NUM> and end at time t<NUM>. The current I<NUM> may have a peak value of <NUM> Amps, <NUM> Amps, or any value within the range <NUM>-<NUM> Amps. Furthermore, the length of time between times t<NUM> and t<NUM> may be <NUM> millisecond, <NUM> milliseconds, or any length of time between <NUM> and <NUM> milliseconds.

The coil looped inductor <NUM> is configured to generate an EMF that is proportional to the current I<NUM>. In particular, the EMF generated by the coil looped inductor <NUM> will be an alternating EMF comprising a sequence of decaying or damped sinusoidal electromagnetic field oscillations. As such, the energy waveform of the generated EMF may correspond to the trace <NUM> shown in <FIG>. The sequence of decaying sinusoidal electromagnetic oscillations, e.g. as shown in <FIG>, may correspond to one pulse of the pulsed EMF <NUM>. As such, the pulsed EMF <NUM> may comprise a series of electromagnetic pulses, each pulse comprising a sequence of damped sinusoidal oscillations. The current generating circuit <NUM> may be configured to provide the current I<NUM> such that it repeats the shape <NUM> shown in <FIG> in a series, so that the coil looped inductor <NUM> generates and emits a series of electromagnetic pulses comprising a sequence of damped sinusoidal oscillations.

Example implementations of the pulsed EMF device <NUM> are described in more detail below.

Reference is made back to <FIG>. The light therapy device <NUM> comprises a coil loop <NUM>, a conditioning circuit <NUM> and a light generating unit <NUM>. The coil loop <NUM> comprises a first terminal 123A and a second terminal 123B. The conditioning circuit <NUM> is electrically coupled to the coil loop <NUM>. In particular, the conditioning circuit <NUM> is electrically coupled to the terminals 123A, 123B of the coil loop <NUM>. The light generating unit <NUM> is electrically coupled to the conditioning circuit <NUM>. As such, the conditioning circuit <NUM> is electrically coupled in between the coil loop <NUM> and the light generating unit <NUM>.

The coil loop <NUM> is arranged to be inductively or magnetically coupled to the coil looped inductor <NUM>. As such, the coil loop will induce a voltage or a potential difference across its terminals 123A and 123B in response to the pulsed EMF <NUM>. The induced voltage will be an AC or alternating voltage corresponding to the pulsed EMF <NUM> and the current I<NUM> in the coil looped inductor <NUM>. In particular, the induced voltage may comprise a sequence of damped or decaying sinusoidal oscillations, in correspondence with the shape of the pulsed EMF <NUM> and the current I<NUM>.

The conditioning circuit <NUM> and the light generating unit <NUM> are coupled to the coil loop <NUM> such that a closed circuit is formed between the terminals 123A and 123B of the coil loop <NUM>. As such, a current I<NUM> is induced through the coil loop <NUM> in response to the voltage induced across the terminals 123A and 123B.

The conditioning circuit <NUM> is configured to receive the current I<NUM> from the coil loop <NUM> and condition the current I<NUM>. The conditioning circuit <NUM> conditions, alters and/or shapes the waveform of the current I<NUM>. The conditioning circuit <NUM> then outputs a conditioned current I<NUM> to the light generating unit <NUM>. The conditioned current I<NUM> has a shape and/or a waveform corresponding to a desired light output intensity of the light generating unit <NUM>. The conditioned current I<NUM> may comprise at least a portion of the original current I<NUM>. Conditioning a current (e.g. the current I<NUM> or otherwise) may be considered as altering, changing, and/or controlling the waveform of said current.

The light generating unit <NUM> is configured to receive the current I<NUM> from the conditioning circuit <NUM>. The light generating unit <NUM> is further configured to emit light <NUM> in response to the current I<NUM>. In particular, the light generating unit <NUM> is configured to emit light <NUM> that has an intensity that is generally proportional to the current I<NUM>. It should be appreciated that different implementations of the light generating unit <NUM> may respond differently to the input current I<NUM>. In some examples, the relationship between the light output of the light generating unit <NUM> and the input current I<NUM> may be substantially linear. In other examples, the relationship between the light output and the input current I<NUM> may be non-linear or curved.

The light generating unit <NUM> is arranged in the light therapy device <NUM> to provide the emitted light <NUM> to a part of the human or animal body. In some examples, the light generating unit <NUM> is arranged to provide the light <NUM> to the same part of the body to which the coil looped inductor <NUM> provides the pulsed EMF <NUM>. In other examples, the light generating unit <NUM> is arranged to provide the light <NUM> to a different part of the body to which the coil looped inductor <NUM> provides the pulsed EMF <NUM>.

Advantageously, the light therapy device <NUM> does not require a power supply in order to supply power to the light generating unit <NUM>. Rather, the light generating unit <NUM> is able to emit light using electrical energy provided by the pulsed EMF device <NUM> via the pulsed EMF <NUM>. Furthermore, with the present arrangement, the intensity of the emitted light <NUM> may be synchronised with the energy waveform of the pulsed EMF <NUM>. This may have further advantages in that the effectiveness of the pulsed EMF therapy and the light therapy is enhanced.

In the illustrated examples, the coil loop <NUM> comprises one turn. However, in some examples, the coil loop <NUM> may comprise two or more turns. The number of turns may be a design choice based on the amount of power required by the light therapy device <NUM>.

Optionally, the light generating unit <NUM> is configured to output infrared (IR) light. Alternatively, the light generating unit <NUM> may output red visible light. However, the light generating unit <NUM> may output light of any other wavelength or frequency at the designer's choice, depending on the type of physiological effect required. For example, the light generating unit <NUM> may output blue visible light, ultraviolet light, or any other wavelength of light between infrared and ultraviolet light.

<FIG> illustrates a more detailed circuit level view of the system <NUM>. The conditioning circuit <NUM> comprises a diode D<NUM> and a capacitor C<NUM>. The conditioning circuit <NUM> further comprises resistors RS1, RL1 and RB1. The diode D<NUM> comprises an anode and a cathode. The anode of the diode D<NUM> is coupled to the first terminal 123A of the coil loop <NUM>. The cathode of the diode D<NUM> is coupled to a first side of the resistor RS1 and a first side of the resistor RL1. A second side of the resistor RS1 is coupled to a first side of the resistor RB1. A second side of the resistor RB1 is coupled to a first terminal 127A of the light generating unit <NUM>. The first terminal 127A of the light generating unit <NUM> may be considered as a positive input terminal of the light generating unit <NUM>. As such, the resistors RS1 and RB1 are arranged in series between the cathode of the diode D<NUM>, and the first terminal 127A of the light generating unit <NUM>. A first side of the capacitor C<NUM> is coupled to the second side of the resistor RS1. A second side of the capacitor C<NUM> is coupled to the second terminal 123B of the coil loop <NUM> and a second terminal 127B of the light generating unit <NUM>. The second terminal 127B of the light generating unit <NUM> may be considered as a negative input terminal of the light generating unit <NUM> As such, the capacitor C<NUM> is coupled between a common node between the resistors RS1 and RB1, and a common node between the second terminal 123B of the coil loop <NUM> and the second terminal 127B of the light generating unit <NUM>. A second side of the resistor RL1 is coupled to the first terminal 127A of the light generating unit <NUM>. As such, the resistor RL1 is arranged in series between the cathode of the diode D<NUM> and the first terminal 127A of the light generating unit. The resistor RL1 is simultaneously in parallel with the series pair of resistors RS1 and RB1.

The diode D<NUM> is arranged to rectify the current I<NUM>. In particular, the diode D<NUM> is configured to only pass a positive current from its anode to its cathode. As such, the diode D1 may be considered as a half-wave rectifier. Consequently, the current I<NUM> will only flow in a positive direction, e.g. clockwise around the light therapy device <NUM> from the first terminal 123A to the second terminal 123B.

The resistor RL1 forms a resistive path between the rectifier D<NUM> and the input to the light generating unit <NUM>. The resistive path receives a first portion of the current I<NUM> and attenuates said first portion. The amount of attenuation depends on the value of the resistor RL1. The resistive path outputs the attenuated current IL1. <FIG> illustrates an oscilloscope trace <NUM> showing the waveform of the attenuated current IL1 between times t<NUM> and t<NUM>. As shown, the current IL1 resembles a half-wave rectified (and attenuated) version of the current I<NUM> shown in <FIG> between times t1 and t2. In particular, the current IL1 comprises a sequence of peaks <NUM> that will be synchronised with and/or correspond to the positive peaks of the current I<NUM> shown in <FIG>. The value of the resistor RL1 can be selected to tune the overall amplitude of the peaks <NUM> of the current IL1. For example, a larger resistance RL1 will result in more attenuated (e.g. shorter) peaks <NUM>, whereas a smaller resistance RL1 will result in less attenuated (e.g. taller) peaks <NUM>. However, the peaks <NUM> will still having an overall decaying shape as determined by the shape of the current I<NUM>. The current path of the current IL1 through the resistor RL1 may be considered as a high frequency path. The current IL1 may have a maximum peak value of <NUM> Amp, <NUM> Amps, <NUM> Amps, or any value within the range <NUM>-<NUM> Amps.

The resistors RS1 and RB1, and the capacitor C<NUM>, together form a low-pass filter (LPF) between the rectifier D<NUM> and the light generating unit <NUM>, and in parallel with the resistor RL1. The LPF is configured to receive and filter a second portion of the current I<NUM>, and output a filtered current IB1. <FIG> further illustrates an oscilloscope trace <NUM> showing the waveform of the filtered current IB1 between times t1 and t2. As shown, the current IB1 resembles a half-wave rectified and subsequently smoothed version of the current I<NUM>. In particular, the current IB1 comprises a smooth pulse <NUM> that lasts over the duration of the current I<NUM> and the pulsed EMF <NUM> (e.g. between times t1 and t2). The values of the resistor RS1 and capacitor C<NUM> may be selected so that the low pass filter has an appropriate cut-off frequency to provide the smooth pulse <NUM>. Furthermore, the value of the resistor RB1 may be selected to control the overall current generated by the LPF. In particular, RB1 may control overall amplitude of the smooth pulse <NUM>. For example, a larger resistor RB1 may result in the smooth pulse <NUM> having a more attenuated (e.g. smaller) amplitude. A smaller resistor RB1 may result in the smooth pulse <NUM> having a less attenuated (e.g. larger) amplitude. The current path of the current IB1 through the resistors RS1 and RB1 may be considered as a low frequency path. The smooth pulse <NUM> of the current IB1 may have a maximum peak value of <NUM> Amps, or any value within the range <NUM>-<NUM> Amps.

Furthermore, the smooth pulse of the current IB1 may have a duration of <NUM> millisecond, <NUM> milliseconds, or any amount of time within the range <NUM>-<NUM> milliseconds.

The components RS1, RL1, RB1 and C<NUM> may be considered together as an interface circuit comprising the resistive path and the low-pass filter described above.

Reference is now made back to <FIG>. Since the resistors RL1 and RB1 are coupled to the same terminal 127A, the currents IL1 and IB1 will be summed or superimposed to form the current I<NUM>. The current I<NUM> is then supplied to the light generating unit <NUM> as described above. <FIG> illustrates an oscilloscope trace <NUM> showing the waveform of the current I<NUM>. As shown, the current I<NUM> comprises the sequence of peaks <NUM> synchronised with or corresponding to the positive peaks of the current I<NUM> (and correspondingly the positive energy peaks of the pulsed EMF <NUM>). The current I<NUM> also comprises the smooth pulse <NUM> over the duration of the current I<NUM> and the EMF pulse. Due to the current path provided by the capacitor C1, the current I<NUM> may comprise some but not all of the current I<NUM>. The current I<NUM> may have a maximum peak value of <NUM> Amps, <NUM> Amps, <NUM> Amps, or any other value within the range <NUM>-<NUM> Amps.

Referring to <FIG>, the light generating unit <NUM> comprises a plurality of light-emitting diodes (LEDs). The light generating unit <NUM> comprises five LEDs LED1, LED2, LED3, LED4, and LED5. The LEDs LED1-LED5 are arranged in series between the first (e.g. positive) input terminal 127A and the second (e.g. negative) input terminal 127B of the light generating unit <NUM>. In particular, an anode of the LED1 is coupled to the first input terminal 127A. An anode of the LED2 is coupled to a cathode of the LED1. An anode of the LED3 is coupled to a cathode of the LED2. An anode of the LED4 is coupled to a cathode of the LED3. An anode of the LED5 is coupled to a cathode of the LED4. A cathode of the LED5 is coupled to the second input terminal 127B. The second input terminal 127B is coupled to the second terminal 123B of the coil loop <NUM>.

Each LED LED1-LED5 is configured to emit light in response to the current I<NUM>. In particular, each LED1-LED5 emits light that has an intensity that is generally proportional to the current level I<NUM>. In some examples, the relationship between the light output of the LEDs and the input current I<NUM> may be substantially linear. In other examples however, the relationship between the light output and the input current I<NUM> may be non-linear or curved. The precise current-response relationship between the light output and the current I<NUM> may depend on the characteristics of the LEDs. The light outputs of the LEDs LED1-LED5 combine to form the light <NUM> emitted by the light generating unit <NUM>. For example, the LEDs LED1-LED5 may be arranged in an array to provide the combined light output <NUM>.

The LEDs are arranged to be placed adjacent to, near or around a part of the body (e.g. a limb or joint).

<FIG> illustrates the intensity of the emitted light <NUM> as a function of time between the times t1 and t2. As shown, the emitted light comprises a light pulse <NUM> between the times t1 and t2. The light pulse <NUM> has an intensity that is proportional to the current I<NUM>. In particular, the light pulse <NUM> comprises a sequence of decaying peaks <NUM>. The sequence of decaying peaks <NUM> are synchronised with or correspond with the peaks <NUM> of the current I<NUM>. Consequently, the peaks <NUM> are synchronised with or correspond with the positive peaks of the current I<NUM> in the inductor <NUM>, and the positive peaks of the EMF pulse <NUM>. The light pulse <NUM> further comprises a low-frequency pulse <NUM>. The low frequency pulse <NUM> lasts over the duration of the light pulse <NUM> between times t1 and t2. The low-frequency pulse <NUM> corresponds with the low-frequency pulse <NUM> of the current I<NUM> shown in <FIG>. As will be appreciated, values of the components RS1, RB1, RL1 and C<NUM> can be chosen to shape the current I<NUM>, and consequently control the intensity of the light that is outputted by the LEDs in response to the EMF pulse <NUM>. The component of the light pulse <NUM> corresponding to the sequence of peaks <NUM> (i.e. the high frequency component of the light pulse <NUM>) may have a maximum peak intensity of <NUM> W/cm<NUM>, <NUM> W/cm<NUM>, or any value between <NUM>-<NUM> W/cm<NUM>. The low frequency pulse <NUM> of the light pulse <NUM> (i.e. the low frequency component of the light pulse <NUM>) may have a peak intensity of <NUM> mW/cm<NUM>, <NUM> mW/cm<NUM>, or any value between <NUM>-<NUM> mW/cm<NUM>. The low frequency pulse <NUM> may have a duration of <NUM> millisecond, <NUM> milliseconds, or for any amount of time between <NUM>-<NUM> milliseconds. Over time, the light generating unit may output a plurality of light pulses <NUM>. In one example, over a period of <NUM> minutes, the light generating unit may output a total light energy of <NUM> J/cm<NUM>, <NUM> J/cm<NUM> or any value between <NUM>-<NUM> J/cm<NUM>.

Advantageously, synchronising the peaks <NUM> of the light pulse <NUM> with the peaks of the EMF pulse <NUM> has been found to provide an overall enhanced physiological effect on the human or animal body. Thus, the synchronisation may result in enhanced pulsed EMF therapy and light therapy. Furthermore, the low-frequency pulse <NUM> means that the light pulse <NUM> is observed by a human as a single "blink" over the duration of the light pulse <NUM>. Therefore, the low frequency pulse <NUM> may protect the human eyes from the higher intensity peaks <NUM> of light. Otherwise, an observer might only observe high intensity flashes of light caused by the high intensity peaks <NUM>, which may cause damage to the observer's eyes.

In the illustrated example of <FIG>, the light generating unit <NUM> comprises five LEDs LED1, LED2, LED3, LED4, and LED5. However, in other examples, the light generating unit <NUM> may comprise any number of LEDs. For example, the light generating unit <NUM> may comprise one or more LEDs. Where the light generating unit <NUM> comprises one LED, the LED may be arranged with its anode coupled to the first input terminal 127A and its cathode coupled to the second input terminal 127B.

<FIG> shows a structural view of the system <NUM>. The system <NUM> comprises a housing <NUM>. The housing <NUM> contains or encloses the light therapy device <NUM>. In particular, the circuitry of the light therapy device <NUM>, including the coil loop <NUM>, conditioning circuit <NUM> and light generating unit <NUM>, are contained in the housing <NUM>. The housing <NUM> may be shaped and/or dimensioned to be a similar size to the coil looped inductor <NUM> of the pulsed EMF device <NUM>. For example, the housing may have a length that is the same or less than a diameter of the coil looped inductor <NUM>, and a width that is the same or less than the diameter of the coil looped inductor <NUM>.

The housing <NUM> comprises a plurality of clips 320A, 320B, 320C and 320D. The clips 320A, 320B, 320C and 320D are configured to secure or attach the housing <NUM> to the coil looped inductor <NUM>.

<FIG> also indicates an example arrangement of the coil loop <NUM>, conditioning circuit <NUM> and the light generating unit <NUM> within the housing <NUM>. The coil loop <NUM> may be arranged within the housing <NUM> such that the coil loop <NUM> is in close proximity to the coil looped inductor <NUM> when the housing <NUM> is attached to the coil looped inductor <NUM>. In particular, the coil loop <NUM> may be arranged such that the coil loop <NUM> is inductively or magnetically coupled with the coil looped inductor <NUM>. Optionally, as shown in <FIG>, the coil loop <NUM> is arranged in the housing <NUM> so that it shares the same axis as the coil looped inductor <NUM> when the housing is attached to the coil looped inductor <NUM>. Advantageously, this has been found to improve the inductive coupling between the coil looped inductor <NUM> and the coil loop <NUM> and the efficiency of energy transfer between the coil looped inductor <NUM> and the coil loop <NUM>. However, in other examples, the coil loop <NUM> may not necessarily share the same axis as the coil looped inductor <NUM>. For example, the coil loop <NUM> may be arranged to have an axis that is different to the axis of the coil looped inductor <NUM>. In some examples, the coil loop <NUM> may be arranged to have an axis that is different to but in parallel with the axis of the coil looped inductor <NUM>.

The light generating unit <NUM> may be arranged in the housing <NUM> such that the light generating unit <NUM> emits light <NUM> to the same body part to which the coil looped inductor emits the pulsed EMF <NUM>. For example, the light generating unit <NUM> may be arranged in the housing <NUM> to emit light <NUM> along the axis of the coil looped inductor <NUM>. Optionally, as shown in <FIG>, the light generating unit <NUM> is arranged in the centre of the coil loop <NUM>. Advantageously, by providing the pulsed EMF <NUM> and the light <NUM> to the same body part, the pulsed EMF <NUM> and the light <NUM> may work together to provide an enhanced physiological effect on the body.

In some examples, the system <NUM> is contained in a further housing (not shown in <FIG>). In particular, both the housing <NUM> and the pulsed EMF device (e.g. the circuitry <NUM> and the coil looped inductor <NUM>), may be contained in the same common housing. Advantageously, the system <NUM> may be provided as a single, compact device that is capable of providing both pulsed EMF therapy and light therapy.

In other examples, the system <NUM> may not be entirely contained in a single housing. Instead, the pulsed EMF device <NUM> may be contained in a separate housing (not shown) without the light therapy device <NUM>. The housing <NUM> containing the light therapy device <NUM> may be configured to attach to the housing containing the pulsed EMF device <NUM> such that the coil loop <NUM> is inductively coupled with the coil looped inductor <NUM> and the light therapy device <NUM> operates as described above. As such, in this example, the system <NUM> may be provided as a modular system comprising a pulsed EMF device with a detachable light therapy device <NUM>. Advantageously, a user can choose whether or not to use the light therapy device <NUM> in combination with the pulsed EMF device <NUM>.

In another example, some of the pulsed EMF device <NUM> may be comprised in a separate housing (not shown). In particular, the circuitry <NUM> and other parts of the pulsed EMF device <NUM> may be comprised in the separate housing, but the coil loop inductor <NUM> may protrude from, extend from or otherwise be external to the separate housing. As such, the coil looped inductor <NUM> may be exposed. It will be appreciated that the coil looped inductor <NUM> can be suitably insulated such that it is safe to touch and operate the pulsed EMF device <NUM>. The housing <NUM> containing the light therapy device <NUM> may be configured to attach to the coil looped inductor <NUM> as is described above, for example with the clips 320A, 320B, 320C and 320D. Advantageously, the system <NUM> can be provided as a modular system.

As shown in <FIG> and described above, the housing <NUM> containing the light therapy device <NUM> can attach to the coil looped inductor <NUM> of the pulsed EMF device <NUM>. When attached, the coil loop <NUM> is inductively or magnetically coupled with the coil looped inductor <NUM> and therefore the light therapy device <NUM> can harvest and use power from the EMF pulses emitted by the coil looped inductor <NUM> in order to emit light. When the coil looped inductor <NUM> is positioned close to a body part, said body part can benefit from the combined physiological effect of the emitted light and EMF pulses.

<FIG> shows an alternative way of using the system <NUM>. In particular, <FIG> shows an alternative way in which the light therapy device <NUM> can be used in combination with the pulsed EMF device <NUM>. The light therapy device <NUM> can be attached to or otherwise secured to a human or animal body part that is to undergo light treatment. The example of <FIG> shows the light therapy device <NUM> attached to a leg <NUM> of a horse. The light therapy device <NUM> can include means for attaching the light therapy device <NUM> to the leg <NUM>. For example as shown, the light therapy device <NUM> can include a strap <NUM>. In use, the coil looped inductor <NUM> is positioned close to and moved over the leg <NUM> to provide pulsed EMF treatment to the leg <NUM>. When the coil looped inductor <NUM> is in the proximity of the light therapy device <NUM> the light therapy device <NUM> will be powered by the EMF pulses emitted by the coil looped inductor <NUM>, as already described above. In particular, the coil loop <NUM> in the light therapy device <NUM> induces a current in response to the EMF pulses. The LEDs in the light therapy device <NUM> will receive at least some of the induced current and emit light pulses to provide light treatment to the leg <NUM> as already described. Moreover, the leg <NUM> will benefit from the combined physiological effects of the emitted light and the EMF pulses. In such examples, the light therapy device <NUM> is used as a wearable device that is physically separate to the pulsed EMF device <NUM>, instead of as a modular attachment of the pulsed EMF device <NUM> as shown in <FIG>. Optionally the LEDs are located on the underside of the light therapy device <NUM> between the device <NUM> and the leg <NUM>, in order to provide the light pulses to the leg <NUM>. It will be appreciated that the light therapy device <NUM> can be secured or attached to any other human or animal body parts in a similar way.

The amount of power transferred between the coil looped inductor <NUM> and the coil loop <NUM> depends on the orientation of the coil looped inductor <NUM> relative to the coil loop <NUM>. Power transfer between the coil looped inductor <NUM> and the coil loop <NUM> is maximal when both loops <NUM> and <NUM> lie in parallel planes and share the same axis. This may be considered as the optimal alignment or orientation between the loops <NUM> and <NUM>. The power transfer is further increased when the loops <NUM> and <NUM> are as close as possible to one another. However, when the light therapy device <NUM> is used as a wearable device, optimal power transfer between the loops <NUM> and <NUM> may be inconsistent during use. For example, the user may not consistently provide the coil looped inductor <NUM> in the correct alignment or orientation with respect to the coil loop <NUM> when the coil looped inductor <NUM> is positioned over the light therapy device <NUM>. More particular, the user may not provide the coil looped inductor <NUM> in a plane that is parallel to the plane of the coil loop <NUM>. Rather, through user error, the coil looped inductor <NUM> may be provided in a plane that is angled relative to the plane of the coil loop <NUM>. Consequently, the axes of the loops <NUM> and <NUM> are also misaligned. This can result in intermittent or inconsistent power transfer to the light therapy device <NUM>, and lead to ineffective light therapy treatment from the device <NUM>.

As described in more detail below, according to the invention the light therapy device includes at least two coil loops. The coil loops are arranged in different planes. In particular, the coil loops can be arranged in different planes that intersect at angles to one another. Optionally, the different planes are orthogonal, or at about <NUM> degrees, to one another. Consequently, the power transfer between the coil looped inductor <NUM> and the light therapy device can be made independent of the angle of the coil looped inductor relative to the light therapy device. Advantageously, this angular independence enables consistent and maximal power transfer from the coil looped inductor <NUM> to the light therapy device, independent of the orientation of the coil looped inductor <NUM>.

<FIG> shows a circuit schematic of a light therapy device <NUM>' which achieves the above-described angular independence. The light therapy device <NUM>' corresponds to the light therapy device <NUM> described previously, but with the following differences. The light therapy device <NUM>' further includes a second coil loop <NUM>'. The second coil loop <NUM>' has a first terminal 123A' and a second terminal 123B'. The conditioning circuit <NUM>' is electrically coupled to the second coil loop <NUM>'. In particular, the conditioning circuit <NUM>' is electrically coupled to the terminals 123A', 123B' of the second coil loop <NUM>'. As such, the conditioning circuit <NUM>' is electrically coupled in between the second coil loop <NUM>' and the light generating unit <NUM> as well as in between the first coil loop <NUM> and the light generating unit <NUM>. Moreover, the second terminal 123B' of the second coil loop <NUM>' is coupled to the second terminal 123B of the first coil loop <NUM> at a common node <NUM>.

The conditioning circuit <NUM>' of the light therapy device <NUM>' further includes a second diode D2. The second diode D2 acts as a rectifier for current generated/induced in the second coil loop <NUM>', similarly to how the diode D1 acts as a rectifier for the current generated/induced in the first coil loop <NUM>. An anode of the diode D2 is coupled to the first terminal 123A' of the second coil loop <NUM>'. A cathode of the diode D2 is coupled to the cathode of the diode D1 at a common node <NUM>. As such, the cathode of the diode D2 is also coupled to first side of the resistor RS1 and the first side of the resistor RL1.

The first coil loop <NUM> and the rectifier D1 are coupled in series between the common nodes <NUM> and <NUM>. The second coil loop <NUM>' and the rectifier D2 are coupled in series between the common nodes <NUM> and <NUM>. Therefore, the series combination of the first coil loop <NUM> and the rectifier D1 is coupled in parallel with the series combination of the second coil loop <NUM>' and the rectifier D2.

Reference is made to <FIG>, which shows a perspective view of the coil loops <NUM> and <NUM>' of the light therapy device <NUM>'. As shown, the first coil loop <NUM> is arranged in a first plane P. The first coil loop <NUM> also has an axis A which is also a normal vector to the first plane P. Furthermore, the second coil loop <NUM>' is arranged in a second plane P' that is different to the first plane P. Although not shown, the first plane P and the second plane P' will intersect at an angle. As such, the planes P and P' are not parallel to one another. The second coil loop <NUM>' also has an axis A' which is also a normal vector to the second plane P'. Optionally, the coil loops <NUM> and <NUM>' are arranged such that their respective planes P and P' are substantially orthogonal or perpendicular. However, it will be appreciated that non-perpendicular or non-orthogonal angles between the planes P and P' can be used. For example, the angle between the planes can be <NUM> degrees to <NUM> degrees.

The operation of the light therapy device <NUM>' is described as follows. The light therapy device <NUM>' can be used as a wearable device by securing or attaching it to an animal or human body part (e.g. as shown in <FIG> and described above). In use, a user may provide the coil looped inductor <NUM> over the light therapy device <NUM>'.

In a first scenario, the coil looped inductor <NUM> is aligned with the first coil loop <NUM>. In particular, the coil loop inductor <NUM> is orientated in a plane that is parallel to the first plane P. The coil loop inductor <NUM> is also provided so that the axis of the coil loop inductor <NUM> is substantially aligned with the axis A. In this scenario, the EMF pulse <NUM> induces a current I<NUM> in the first coil loop <NUM>, which powers the light therapy device <NUM>' as already described with respect to the light therapy device <NUM>. In particular, the current I<NUM> is received by the conditioning circuit <NUM>'. The conditioning circuit <NUM>' conditions, alters and/or shapes the waveform of the current I<NUM> and outputs a conditioned current I<NUM>. The conditioned current I<NUM> is then supplied to the light generating unit <NUM>. The conditioning circuit <NUM>' and the light generating unit <NUM> function as has already described above for the light therapy device <NUM>, and therefore the functionality of the components D1, RS1, RL1, RB1, C<NUM> and LED1-LED5 are not described in detail. Due to the alignment of the coil looped inductor <NUM>, the second coil loop <NUM>' may not induce a sufficient current to contribute to the powering of the light therapy device <NUM>'. However, the coil looped inductor <NUM> is optimally aligned with the first coil loop <NUM> and therefore maximal power transfer is achieved in this orientation.

In a second scenario, the coil looped inductor <NUM> is aligned with the second coil loop <NUM>'. In particular, the coil looped inductor <NUM> is orientated in a plane that is parallel to the second plane P'. The coil looped inductor <NUM> is also provided so that the axis of the coil loop inductor <NUM> is substantially aligned with the axis A'. In this scenario, the EMF pulse <NUM> induces a current I<NUM>' in the second coil loop <NUM>'. However, due to the alignment of the coil looped inductor <NUM>, the first coil loop <NUM> may not induce a sufficient current to contribute to the powering of the light therapy device <NUM>'. Instead, the current I<NUM>' powers the light therapy device <NUM>' similarly to how the current I<NUM> would power the light therapy device <NUM>' in the first scenario above. In particular, the current I<NUM>' is received by the conditioning circuit <NUM>'. The conditioning circuit <NUM>' conditions, alters and/or shapes the waveform of the current I<NUM>' similarly to how the conditioning circuit <NUM>' would condition the current I<NUM>. In particular, the diode D2 rectifies the current I<NUM>' similarly to how the diode D1 would rectify the current I<NUM>. The components RS1, RL1, RB1, C<NUM> (i.e. the interface circuit) further conditions the current I<NUM>' as already described in respect of the current I<NUM>. The conditioning circuit <NUM>' outputs a conditioned current I<NUM>. The conditioned current I<NUM> is then supplied to the light generating unit <NUM>. The light generating unit <NUM> then emits light as already described above. In this scenario, the coil looped inductor <NUM> is optimally aligned with the second coil loop <NUM>' and therefore maximal power transfer is also achieved in this orientation.

In a third scenario, the coil looped inductor <NUM> is angled relative to both coil loops <NUM> and <NUM>'. In particular, the coil looped inductor <NUM> is orientated in a plane that is angled relative to both of the planes P and P'. A current I<NUM> will be induced in the coil loop <NUM> and a current I<NUM>' will also be induced in the coil loop <NUM>'. The diode D1 will rectify the current I<NUM>. The diode D2 will rectify the current I<NUM>'. The rectified currents I<NUM> and I<NUM>' will then be summed at the common node <NUM>. The summed current I<NUM>+I<NUM>' is supplied to the input of the interface circuit (RS1, RL1, RB1, C<NUM>). The interface circuit further conditions the summed current I<NUM>+I<NUM>' as already described above for the current I<NUM>. The conditioning circuit <NUM>' outputs a conditioned current I<NUM>. The conditioned current I<NUM> is then supplied to the light generating unit <NUM>. The light generating unit <NUM> then emits light as already described above.

In the third scenario, the coil looped inductor <NUM> is not optimally aligned with either coil loop <NUM> and <NUM>'. However, weaker currents I<NUM> and I<NUM>' are still induced in both coil loops <NUM> and <NUM>'. The sum of the currents is provided to the rest of the circuit via the common node <NUM>. Advantageously, this enables the light therapy device <NUM>' to achieve maximal power transfer even when the coil looped inductor <NUM> is not optimally aligned with the light therapy device <NUM>'. In particular, the light therapy device <NUM>' is able to achieve more optimal power transfer, independent of the angle between the coil looped inductor <NUM> and the light therapy device <NUM>'. As such, this reduces the risk of inefficient or intermittent power transfer to the light therapy device <NUM>' during use. Moreover, this improves the effectiveness of the light therapy provided by the light therapy device <NUM>', especially when the light therapy device <NUM>' is used as a wearable device.

<FIG> shows an example arrangement of the light therapy device <NUM>' within a housing <NUM>'. In particular, the arrangement of the coil loops <NUM> and <NUM>' within the housing <NUM>' is illustrated. As shown, the housing <NUM>' is shaped or otherwise structured to accommodate the coil loops <NUM> and <NUM>' in the arrangements described above. Furthermore, the housing <NUM>' includes a means <NUM> for securing the housing <NUM>' to an animal or human body part. In the illustrated example, the means <NUM> are buckles for attaching a strap or band which can be looped around the body part. However, it will be appreciated that the housing <NUM>' can include any other means for attaching or securing the housing <NUM>' to a body part. Although not shown, the housing <NUM>' can accommodate the remaining components and circuitry of the light therapy device <NUM>'.

It has been found that the two coil loops <NUM> and <NUM>' are sufficient to observe the improvements in power transfer described above. However, to provide further enhanced angular independence, a third coil loop can optionally be included. The optional third coil loop <NUM>" is shown in <FIG>. The third coil loop <NUM>" has a first terminal 123A" and a second terminal 123B". The conditioning circuit <NUM>' is electrically coupled to the third coil loop <NUM>". In particular, the conditioning circuit <NUM>' is electrically coupled to the terminals 123A", 123B" of the third coil loop <NUM>'. As such, the conditioning circuit <NUM>' is further electrically coupled in between the third coil loop <NUM>" and the light generating unit <NUM>. Moreover, the second terminal 123B" of the third coil loop <NUM>" is coupled to the second terminal 123B of the first coil loop <NUM> and the second terminal 123B' of the second coil loop <NUM>' at the common node <NUM>. The conditioning circuit <NUM>' of the light therapy device <NUM>' further includes a third diode D3. The third diode D3 acts as a rectifier for current generated/induced in the third coil loop <NUM>", similarly to how the diode D1 acts as a rectifier for the current generated/induced in the first coil loop <NUM>. An anode of the diode D3 is coupled to the first terminal 123A" of the third coil loop <NUM>". A cathode of the diode D3 is coupled to the cathode of the diode D2 and the cathode of the diode D1 at the common node <NUM>. As such, the cathode of the diode D3 is also coupled to first side of the resistor RS1 and the first side of the resistor RL1.

The third coil loop <NUM>" and the rectifier D3 are coupled in series between the common nodes <NUM> and <NUM>. Therefore, the series combination of the third coil loop <NUM>" and the rectifier D3 is coupled in parallel with the series combination of the first coil loop <NUM> and the rectifier D1, and the series combination of the second coil loop <NUM>' and the rectifier D2.

With reference to <FIG>, the third coil loop <NUM>" can be arranged in a third plane P" that is different to the first plane P and to the second plane P'. Although not shown, the third plane P" will intersect with both the first plane P and the second plane P' at angles. As such, the plane P" is not parallel with either planes P and P'. The third coil loop <NUM>" may have an axis A" which is also a normal vector to the third plane P". Optionally, the coil loop <NUM>" is arranged such that its plane P" is substantially orthogonal perpendicular to both the first plane P and the second plane P'. In particular, the plane P" is substantially orthogonal to the plane P'. Simultaneously, the plane P" is also substantially orthogonal to the plane P. However, it will be appreciated that non-perpendicular or non-orthogonal angles between the plane P" and the planes P and P' can be used. For example, the angle between the plane P" and the plane P can be <NUM> degrees to <NUM> degrees. Furthermore, the angle between the plane P" and the plane P' can be <NUM> degrees to <NUM> degrees.

In a further scenario during use of the system <NUM>, the coil looped inductor <NUM> can be aligned with the third coil loop <NUM>". In particular, the coil looped inductor <NUM> is orientated in a plane that is parallel to the third plane P". The coil looped inductor <NUM> is also provided so that the axis of the coil loop inductor <NUM> is substantially aligned with the axis A". In this scenario, the EMF pulse <NUM> induces a current I<NUM>" in the third coil loop <NUM>". However, due to the alignment of the coil looped inductor <NUM>, the first coil loop <NUM> and the second coil loop <NUM>' may not induce sufficient currents to contribute to the powering of the light therapy device <NUM>'. Instead, the current I<NUM>" powers the light therapy device <NUM>' similarly to how the current I<NUM> or I<NUM>' would power the light therapy device <NUM>' in the scenarios previously described above. In particular, the current I<NUM>" is received by the conditioning circuit <NUM>'. The conditioning circuit <NUM>' conditions, alters and/or shapes the waveform of the current I<NUM>" similarly to how the conditioning circuit <NUM>' would condition the current I<NUM> or I<NUM>'. In particular, the diode D3 rectifies the current I<NUM>" similarly to how the diode D1 would rectify the current I<NUM>. The components RS1, RL1, RB1, C<NUM> (i.e. the interface circuit) further conditions the current I<NUM>" as already described in respect of the current I<NUM>. The conditioning circuit <NUM>' outputs a conditioned current I<NUM>. The conditioned current I<NUM> is then supplied to the light generating unit <NUM>. The light generating unit <NUM> then emits light as already described above. In this scenario, the coil looped inductor <NUM> is optimally aligned with the third coil loop <NUM>" and therefore maximal power transfer is also achieved in this orientation.

In another scenario during use of the system <NUM>, the coil looped inductor <NUM> is angled relative to all of the coil loops <NUM>, <NUM>' and <NUM>". In particular, the coil looped inductor <NUM> is orientated in a plane that is angled relative to each of the planes P, P' and P". A current I<NUM> will be induced in the coil loop <NUM>, a current I<NUM>' will be induced in the coil loop <NUM>', and a current I<NUM>" will also be induced in the coil loop <NUM>". The diode D1 will rectify the current I<NUM>. The diode D2 will rectify the current I<NUM>'. The diode D3 will rectify the current I<NUM>". The rectified currents I<NUM>, I<NUM>' and I<NUM>" will then be summed at the common node <NUM>. The summed current I<NUM>+I<NUM>'+I<NUM>" is supplied to the input of the interface circuit (RS1, RL1, RB1, C<NUM>). The interface circuit further conditions the summed current I<NUM>+I<NUM>'+I<NUM>" as already described above for the current I<NUM>. The conditioning circuit <NUM>' outputs a conditioned current I<NUM>. The conditioned current I<NUM> is then supplied to the light generating unit <NUM>. The light generating unit <NUM> then emits light as already described above.

In the third scenario, the coil looped inductor <NUM> is not optimally aligned with either coil loops <NUM>, <NUM>' or <NUM>". However, weaker currents I<NUM>, I<NUM>' and I<NUM>" are still induced in the respective coil loops <NUM>, <NUM>' and <NUM>". The sum of the currents is provided to the rest of the circuit via the common node <NUM>. Advantageously, this enables the light therapy device <NUM>' to achieve further improved power transfer even when the coil looped inductor <NUM> is not optimally aligned with the light therapy device <NUM>'. In particular, the light therapy device <NUM>' is able to achieve more optimal power transfer, independent of the angle between the coil looped inductor <NUM> and the light therapy device <NUM>'. As such, this further reduces the risk of inefficient or intermittent power transfer to the light therapy device <NUM>' during use. Moreover, this further improves the effectiveness of the light therapy provided by the light therapy device <NUM>', especially when the light therapy device <NUM>' is used as a wearable device.

In the illustrated examples, each coil loop <NUM>, <NUM>' and <NUM>" comprises one turn. However, in some examples, each coil loop <NUM>, <NUM>' and <NUM>" may comprise two or more turns. The number of turns may be a design choice based on the amount of power required by the light therapy device <NUM>'. Optionally, each coil loop <NUM>, <NUM>' and <NUM>" has the same number of turns. Alternatively, the coil loops can have different numbers of turns. With reference to <FIG>, in one example, the first coil loop <NUM> can have one turn. Although not shown, the second coil loop <NUM>' can have any different number of turns, e.g. two, three, four or more turns. If the second coil loop <NUM>' has more turns, the second coil loop <NUM>' can be reduced in height or width in comparison to the first coil loop <NUM>, whilst achieving a similar inductance characteristic to the first coil loop <NUM>. This may enable the coil loops <NUM> and <NUM>' to better fit into the housing <NUM>'. For example, the vertically positioned second coil loop <NUM>' can be made to have more than one turn. This will allow the height of the coil loop <NUM>' to be reduced without significantly impacting its inductance, so that the coil loop <NUM>' can better fit into a housing <NUM>' that has limited height. In one example, the coil loop <NUM> can have one turn. The coil loop <NUM>' can have four turns, but have a quarter of the height of the coil loop <NUM>.

The system <NUM> described above combines a pulsed EMF therapy device <NUM> and a light therapy device <NUM>, whereby the light therapy device <NUM> is powered by the pulsed EMF <NUM> emitted by the pulsed EMF device <NUM> without the need for a separate power supply. Similar principles to those described above may be used to power alternative devices to the light therapy device <NUM>.

In one alternative example, the light therapy device <NUM> may be replaced with an ultrasound therapy device. For example, <FIG> shows a system <NUM> comprising the pulsed EMF device <NUM> and an ultrasound therapy device <NUM>. The pulsed EMF therapy device <NUM> is configured to generate and emit a pulsed EMF <NUM> as already described above.

The ultrasound therapy device <NUM> is configured to emit an ultrasound wave <NUM> in response to the pulsed EMF <NUM>. In particular, the ultrasound therapy device <NUM> is configured to convert the pulsed EMF <NUM> into electrical energy and generate the ultrasound wave <NUM> based on the electrical energy. Advantageously, the ultrasound therapy device <NUM> is able to generate and emit the ultrasound wave <NUM> based on the pulsed EMF <NUM>, without requiring a power source or a power supply.

The ultrasound therapy device <NUM> comprises a coil loop <NUM>, a conditioning circuit <NUM> and an ultrasound generating unit <NUM>. The coil loop <NUM> comprises a first terminal 723A and a second terminal 723B. The conditioning circuit <NUM> is electrically coupled to the coil loop <NUM>. In particular, the conditioning circuit <NUM> is electrically coupled to the terminals 723A, 723B of the coil loop <NUM>. The ultrasound generating unit <NUM> is electrically coupled to the conditioning circuit <NUM>. As such, the conditioning circuit <NUM> is electrically coupled in between the coil loop <NUM> and the ultrasound generating unit <NUM>.

The coil loop <NUM> is arranged to be inductively or magnetically coupled to the coil looped inductor <NUM>. As such, the coil loop will induce a voltage or a potential difference across its terminals 723A and 723B in response to the pulsed EMF <NUM>. The induced voltage will be an AC or alternating voltage corresponding to the pulsed EMF <NUM> and the current I<NUM> in the coil looped inductor <NUM>. In particular, the induced voltage may comprise a sequence of damped or decaying sinusoidal oscillations, in correspondence with the pulsed EMF <NUM> and the current I<NUM> illustrated in <FIG>.

The conditioning circuit <NUM> and the ultrasound generating unit <NUM> are coupled to the coil loop <NUM> such that a closed circuit is formed between the terminals 723A and 723B of the coil loop <NUM>. As such, a current I<NUM> is induced through the coil loop <NUM> in response to the voltage induced across the terminals 723A and 723B.

The conditioning circuit <NUM> receives the induced voltage and/or current I<NUM> from the coil loop <NUM>. The conditioning circuit <NUM> is configured to limit and/or control the amount of electrical power provided to the ultrasound generating unit <NUM>. For example, the conditioning circuit <NUM> may receive the induced voltage and/or current I<NUM> to provide a conditioned voltage and/or current I<NUM> to the ultrasound generating unit <NUM> that has a reduced electrical power.

As explained below, the ultrasound generating unit <NUM> comprises an ultrasound transducer. Advantageously, with the conditioning circuit <NUM>, the ultrasound transducer can be operated whilst avoiding damage to the ultrasound transducer. The ultrasound transducer may require a relatively high voltage in order to generate an ultrasound signal. Therefore, the coil loop <NUM> may comprise a plurality of turns to meet the voltage requirements of the ultrasound transducer. However, this could result in a large power output of the coil loop <NUM> which has been found to cause damage to the ultrasound transducer. For example, the power output of the coil loop <NUM> may depend on the intensity of the pulsed EMF <NUM> (e.g. the energy and/or magnitude of the EM oscillations). The intensity of the pulsed EMF <NUM> may be controlled by providing user input at the pulsed EMF device <NUM>, or controlled automatically by the pulsed EMF device <NUM>. For a low intensity pulsed EMF <NUM>, the power output of the coil loop <NUM> may not exceed a maximum power rating of the ultrasound transducer. For higher intensity pulsed EMFs, the power output of the coil loop <NUM> may exceed the maximum power rating of the ultrasound transducer, and thereby risk causing damage to the transducer.

The conditioning circuit <NUM> can advantageously be used to reduce the power provided to the ultrasound transducer whilst meeting the high voltage requirements needed to drive the transducer. In particular, the conditioning circuit <NUM> may non-linearly reduce the power provided to the ultrasound transducer. In some examples the conditioning circuit <NUM> may operate to non-linearly reduce the power such that the power provided to the transducer is increasingly reduced, attenuated or limited as the power outputted by the coil loop <NUM> approaches a maximum value. In other examples, the conditioning circuit <NUM> may reduce or cap the power when the power outputted by the coil loop <NUM> exceeds a threshold value.

In some examples, the conditioning circuit <NUM> may also perform impedance matching functions between the coil loop <NUM> and the ultrasound generating unit <NUM>. Advantageously, impedance matching has been found to improve the efficiency of the ultrasound device <NUM> and reduce damage to the ultrasound transducer.

The ultrasound generating unit <NUM> is configured to receive the conditioned voltage and/or current I<NUM> from the conditioning circuit <NUM>. The ultrasound generating unit <NUM> is further configured to emit an ultrasound wave <NUM> in response to the conditioned voltage and/or current I<NUM>. In particular, the ultrasound generating unit <NUM> is configured to emit an ultrasound wave <NUM> that has a power level or intensity that is generally proportional to the conditioned voltage and/or current I<NUM>. It should be appreciated that different implementations of the ultrasound generating unit <NUM> may respond differently to the conditioned voltage and/or current I<NUM>.

As shown in <FIG>, the ultrasound generating unit <NUM> comprises an ultrasound transducer UT1. The ultrasound transducer UT1 is configured to emit the ultrasound wave <NUM> as described above. Optionally, the ultrasound transducer UT1 is self-resonant at the oscillation frequency of the current I<NUM> and the EMF pulse <NUM>. For example, the oscillation frequency of the current I<NUM> and the EMF pulse <NUM> may be approximately <NUM>. In this case the ultrasound transducer UT1 is optionally self-resonant at a frequency of <NUM>. In other examples, the ultrasound transducer UT1 is not self-resonant.

Optionally, the ultrasound transducer UT1 is driven by an AC driving voltage of 50V, 1000V or any voltage between <NUM>-1000V. Optionally, the transducer UT1 is driven by an AC driving voltage of 500V.

The ultrasound generating unit <NUM> is arranged in the ultrasound therapy device <NUM> to provide the emitted ultrasound wave <NUM> to a part of the human or animal body. In particular, the ultrasound transducer UT1 is arranged so that it can be coupled to a part of the body that has been treated with gel, in order to provide the ultrasound wave <NUM> to that part of the body. In some examples, the ultrasound transducer UT1 is arranged to provide the ultrasound wave <NUM> to the same part of the body to which the coil looped inductor <NUM> provides the pulsed EMF <NUM>. In other examples, the ultrasound transducer UT1 is arranged to provide the ultrasound wave <NUM> to a different part of the body to which the coil looped inductor <NUM> provides the pulsed EMF <NUM>.

<FIG> illustrates an example structural arrangement of the ultrasound device <NUM> with respect to the coil looped inductor <NUM>. The system <NUM> comprises a housing <NUM>. The housing <NUM> contains or encloses the ultrasound therapy device <NUM>. In particular, the circuitry of the ultrasound therapy device <NUM>, including the coil loop <NUM>, conditioning circuit <NUM> and ultrasound generating unit <NUM>, are contained in the housing <NUM>. The housing <NUM> may be shaped and/or dimensioned to be a similar size to the coil looped inductor <NUM> of the pulsed EMF device <NUM>. For example, the housing may have a length that is the same or less than a diameter of the coil looped inductor <NUM>, and a width that is the same or less than the diameter of the coil looped inductor <NUM>.

The housing <NUM> comprises a plurality of clips 920A, 920B, 920C and 920D. The clips 920A, 920B, 920C and 920D are configured to secure or attach the housing <NUM> to the coil looped inductor <NUM>.

<FIG> further indicates an example arrangement of the coil loop <NUM>, conditioning circuit <NUM> and the ultrasound transducer UT1 within the housing <NUM>. The coil loop <NUM> may be arranged within the housing <NUM> such that the coil loop <NUM> is in close proximity to the coil looped inductor <NUM> when the housing <NUM> is attached to the coil looped inductor <NUM>. In particular, the coil loop <NUM> may be arranged such that the coil loop <NUM> is inductively or magnetically coupled with the coil looped inductor <NUM>. Optionally, as shown in <FIG>, the coil loop <NUM> is arranged in the housing <NUM> so that it shares the same axis as the coil looped inductor <NUM> when the housing <NUM> is attached to the coil looped inductor <NUM>. Advantageously, this has been found to improve the inductive coupling between the coil looped inductor <NUM> and the coil loop <NUM> and the efficiency of energy transfer between the coil looped inductor <NUM> and the coil loop <NUM>. However, in other examples, the coil loop <NUM> may not necessarily share the same axis as the coil looped inductor <NUM>. For example, the coil loop <NUM> may have an axis that is different to but in parallel with the axis of the coil looped inductor <NUM>. Alternatively, the coil loop <NUM> may have an axis that is different to and not on parallel with the axis of the coil looped inductor <NUM>.

The ultrasound transducer UT1 may be arranged in the housing <NUM> such that the ultrasound transducer UT1 emits the ultrasound wave <NUM> to the same body part to which the coil looped inductor emits the pulsed EMF <NUM>. For example, the ultrasound generating unit <NUM> may be arranged in the housing <NUM> to emit the ultrasound wave <NUM> along the axis of the coil looped inductor <NUM>. Advantageously, by providing the pulsed EMF <NUM> and the ultrasound wave <NUM> to the same body part, the pulsed EMF <NUM> and the ultrasound wave <NUM> may work together to provide an enhanced physiological effect on the body.

Advantageously, the ultrasound therapy device <NUM> does not required a power supply in order to supply power to the ultrasound generating unit <NUM>. Rather, the ultrasound generating unit <NUM> is able to emit the ultrasound wave <NUM> using electrical energy provided by the pulsed EMF device <NUM>. Furthermore, with the present arrangement, the intensity or waveform peaks of the emitted ultrasound wave <NUM> may be synchronised with the waveform peaks of the pulsed EMF <NUM>. This may have further advantages in that the effectiveness of the pulsed EMF therapy and the ultrasound therapy is enhanced.

In some examples, the system <NUM> is contained in a further housing (not shown in <FIG>). In particular, both the housing <NUM> and the pulsed EMF device (e.g. the circuitry <NUM> and the coil looped inductor <NUM>), may be contained in the same common housing. Advantageously, the system <NUM> may be provided as a single, compact device that is capable of providing both pulsed EMF therapy and ultrasound therapy.

In other examples, the system <NUM> may not be entirely contained in a single housing. Instead, the pulsed EMF device <NUM> may be contained in a separate housing (not shown) without the ultrasound therapy device <NUM>. The housing <NUM> containing the ultrasound therapy device <NUM> may be configured to attach to the housing containing the pulsed EMF device <NUM> such that the coil loop <NUM> is inductively coupled with the coil looped inductor <NUM> and the ultrasound therapy device <NUM> operates as described above. As such, in this example, the system <NUM> may be provided as a modular system comprising a pulsed EMF device with a detachable ultrasound therapy device <NUM>. Advantageously, a user can choose whether or not to use the ultrasound therapy device <NUM> in combination with the pulsed EMF device <NUM>.

In another example, some of the pulsed EMF device <NUM> may be comprised in a separate housing (not shown). In particular, the circuitry <NUM> and other parts of the pulsed EMF device <NUM> may be comprised in the separate housing, but the coil loop inductor <NUM> may protrude from, extend from or otherwise be external to the separate housing. As such, the coil looped inductor <NUM> may be exposed. It will be appreciated that the coil looped inductor <NUM> can be suitably insulated such that it is safe to touch and operate the pulsed EMF device <NUM>. The housing <NUM> containing the ultrasound therapy device <NUM> may be configured to attach to the coil looped inductor <NUM> as is described above, for example with the clips 920A, 920B, 920C and 920D. Advantageously, the system <NUM> can be provided as a modular system.

In the illustrated examples, the coil loop <NUM> comprises one turn. However, in some examples, the coil loop <NUM> may comprise two or more turns. The number of turns may be a design choice based on the amount of power required in the ultrasound therapy device <NUM>.

In the illustrated examples, the ultrasound therapy device <NUM> includes one coil loop <NUM>. In alternative examples, the ultrasound therapy device <NUM> can include two or three coil loops as described above in respect of the light therapy device <NUM>'. For example, the additional coil loop(s) can be coupled in parallel with the coil loop <NUM> shown in <FIG>. The coil loops can be arranged in different planes as described above and shown in <FIG>. Advantageously, the ultrasound therapy device <NUM> can be used as a wearable device like the light therapy device <NUM>' whilst achieving optimal power transfer between the coil looped inductor <NUM> and the ultrasound therapy device <NUM>.

In other alternative systems, the light therapy device <NUM> or the ultrasound therapy device <NUM> may be replaced with other types of devices. For example, in other example system, the light therapy device <NUM> or the ultrasound therapy device <NUM> may be replaced with a negative ion generating device that is powered using the same principles described above.

Example implementations of the pulsed EMF device <NUM> are described as follows.

<FIG> is a simplified circuit diagram of a first example of a pulsed electromagnetic field (EMF) therapy device <NUM>. The pulsed electromagnetic field therapy device <NUM> has a resonant circuit <NUM> with a capacitor <NUM> connected to a semiconductor switch <NUM> and a coil looped inductor <NUM>.

When the semiconductor switch <NUM> is open, the capacitor <NUM> is charged from a high voltage circuit (not shown). Closing the semiconductor switch <NUM> discharges the capacitor <NUM> into the coil looped inductor <NUM>, initiating oscillation of the resonant circuit <NUM>. With the semiconductor switch <NUM> closed, the resonant circuit <NUM> oscillates until losses in the resonant circuit <NUM> dissipate all of the energy stored in the resonant circuit <NUM>. Thus, when the resonant circuit <NUM> oscillates, a current comprising a sequence of damped or decaying sinusoidal oscillations will flow through the inductor <NUM>. In response to the current, the inductor <NUM> will generate and emit a pulsed EMF correspondingly comprising a sequence of damped or decaying sinusoidal oscillations. The above process may be repeated by opening the switch <NUM> and then closing the switch again to generate further pulses of the pulsed EMF.

The coil looped inductor <NUM> can be placed adjacent to, or around, a part of the body (such as a limb or joint) where the physiological effect of the pulsed electromagnetic field is desired.

As such, the pulsed EMF device <NUM> shown in <FIG> may be used as the pulsed EMF device <NUM> described above, whereby the inductor <NUM> in <FIG> corresponds to the coil looped inductor <NUM> described above.

<FIG> illustrates an example of an improved pulsed electromagnetic field therapy device <NUM>.

The pulsed electromagnetic field therapy device <NUM> has a parallel resonant circuit <NUM> with a capacitor <NUM> arranged in parallel with a coil looped inductor <NUM>. A current ramping circuit <NUM> is external to the parallel resonant circuit <NUM> and connected in parallel to the parallel resonant circuit <NUM>. The current ramping circuit <NUM> includes a high current capability capacitor <NUM> which provides a voltage of around <NUM> V - <NUM> V (typically <NUM> V) and a current of around <NUM> A - <NUM> A. A semiconductor switch <NUM> selectively connects the high current capability capacitor <NUM> to the parallel resonant circuit <NUM> to ramp-up the current in the coil looped inductor <NUM>.

The oscilloscope trace in <FIG> shows the current in the parallel resonant circuit <NUM> as a function of time. The semiconductor switch <NUM> is closed at tx for a current ramping period (indicated by reference numeral <NUM> in <FIG>) of about <NUM> to ramp-up the current in the coil looped inductor <NUM>. At the end of the current ramping period at ty, the semiconductor switch <NUM> is opened, disconnecting the current ramping circuit <NUM> from the parallel resonant circuit <NUM> and preventing further increase in the current in the coil looped inductor <NUM>. At the end of the current ramping period, the current in the coil looped inductor <NUM> has reached a desired current of <NUM> A, which is sufficient to produce a pulsed EMF that provides a physiological effect.

At the end of the current ramping period at ty, and with the semiconductor switch <NUM> open, the current in the coil looped inductor <NUM> initiates oscillation of the parallel resonant circuit <NUM>. As illustrated by the oscilloscope trace in <FIG>, the parallel resonant circuit <NUM> generates a pulsed EMF comprising a sequence of damped sinusoidal oscillations <NUM> in the coil looped inductor <NUM>. The coil looped inductor <NUM> is placed adjacent to, or around, a part of the body (such as a limb or joint) where the physiological effect of the pulsed electromagnetic field is desired.

The parallel resonant circuit <NUM> oscillates until losses in the parallel resonant circuit <NUM> dissipate all of the energy stored in the parallel resonant circuit <NUM>. To generate more pulses of the pulsed EMF, the above process may be repeated by closing the switch <NUM> for another current ramping period, and then opening the switch <NUM>.

Advantageously, the semiconductor switch <NUM> does not need to be a component of the parallel resonant circuit <NUM> in order to control current within the coil looped inductor <NUM>. Instead, current ramping of the parallel resonant circuit <NUM> is controlled by current ramping circuit <NUM> which is external to and connected in parallel to the parallel resonant circuit <NUM>. Not having a semiconductor switch <NUM> as a component of the parallel resonant circuit <NUM> provides a number of benefits.

Resistance losses in the parallel resonant circuit <NUM> are low because the semiconductor switch <NUM> is external to the parallel resonant circuit <NUM>, so resistance losses from the semiconductor switch <NUM> are not incurred during oscillation of the parallel resonant circuit <NUM>. As a result, the decay time of the damped oscillations is much longer which increases the time period over which the pulsed electromagnetic field provides a physiological effect for a given initial current in the coil looped inductor <NUM>. For example, a physiological effect may be present when the current in the parallel resonant circuit <NUM> is greater than around 200A, and the pulsed electromagnetic field therapy device <NUM> enjoys a period of around <NUM> in which the current in the parallel resonant circuit <NUM> is providing a physiological effect, as compared with only <NUM> with the pulsed electromagnetic field therapy device <NUM>. As a result, the pulsed electromagnetic field therapy device <NUM> provides a more sustained physiological effect. Moreover, the coil looped inductor <NUM> need only be ramped to a lower initial current (only <NUM> A - <NUM> A in the pulsed electromagnetic field therapy device <NUM> as compared with <NUM> A - <NUM> A in the pulsed electromagnetic field therapy device <NUM>), leading to lower voltages in the pulsed electromagnetic field therapy device <NUM> which do not require capacitor <NUM> or semiconductor switch <NUM> to be expensive high voltage components, reducing manufacturing costs. Additionally, operating at lower voltages allows capacitor <NUM> to have a larger capacitance value than a higher voltage capacitor of equivalent physical size, and the selection of a larger capacitance value for capacitor <NUM> leads to parallel resonant circuit <NUM> having a lower resonant frequency which allows the pulsed electromagnetic field therapy device <NUM> to meet regulatory requirements regarding electromagnetic interference.

In the pulsed electromagnetic field therapy device <NUM>, the charge from the capacitor <NUM> is dumped into the resonant circuit <NUM> nearly instantaneously when the semiconductor switch <NUM> in the resonant circuit <NUM> is closed. This rapid charge discharged into the resonant circuit <NUM> leads to current reflections which result in significant interference <NUM>. By not having semiconductor switch <NUM> as a component of the parallel resonant circuit <NUM>, the current in the parallel resonant circuit <NUM> is increased more gradually over the course of the current ramping period <NUM>. This, combined with the fact that the semiconductor switch <NUM> is external to and disconnected from the parallel resonant circuit <NUM> after the current ramping period <NUM> so that the impedance mismatched semiconductor switch <NUM> does not lead to reflections, results in a current profile in the parallel resonant circuit <NUM> which is sinusoidal with low distortion, and which does not show the large amount of interference <NUM> that may be seen in the pulsed electromagnetic field therapy device <NUM>.

The pulsed EMF device <NUM> shown in <FIG> may be used as the pulsed EMF device <NUM> described above, whereby the inductor <NUM> in <FIG> corresponds to the coil looped inductor <NUM> described above.

<FIG> illustrates an alternative example of an improved pulsed electromagnetic field therapy device <NUM>. The pulsed electromagnetic field therapy device <NUM> is generally the same as the pulsed electromagnetic field therapy device <NUM>, with some improvements to electrical safety, charging and control.

The pulsed electromagnetic field may show no significant physiological effect once the current in the parallel resonant circuit <NUM> has dropped below a certain current (for example, once the current in the parallel resonant circuit <NUM> has dropped below <NUM> A). Therefore, a current threshold may be selected based on a current below which little or no significant physiological effect is observed, or below which insufficient physiological effect is observed to meet the needs of a particular physiological or therapeutic application.

Once the current in the parallel resonant circuit <NUM> has dropped below the current threshold (at a time tz following time ty), a further switch <NUM> is closed which connects the parallel resonant circuit <NUM> to the capacitor bank <NUM>. This substantially reduces oscillation of the parallel resonant circuit <NUM> and allows at least part of the energy remaining in the parallel resonant circuit <NUM> to be recycled to at least partially recharge the capacitor bank <NUM>. This saves considerable energy that might otherwise be wasted generating a pulsed electromagnetic field which provides no physiological effect.

Instead of a single high current capability capacitor <NUM>, the pulsed electromagnetic field therapy device <NUM> has a capacitor bank <NUM> which is made up of capacitors 53a and 53b connected in parallel which together offer a high current capability source. The use of capacitor bank <NUM> may provide redundancy in case a capacitor 53a or 53b fails, and may be cheaper than using a single high current capability capacitor <NUM>. The capacitor bank <NUM> could provide a high current capability source using more than two capacitors. In fact, it may be beneficial for the capacitor bank <NUM> to combine a large number of cheap, lower value capacitors which are smaller and therefore easier to pack into spare space in a housing.

The capacitor bank <NUM> is charged from power source <NUM>. In some examples, the power source <NUM> is fed from a mains electricity supply. However, the power supply <NUM> may be any electrical power source, such as a mains power supply or a battery. To improve electrical safety, and reduce the risk of a patient or operator receiving an electrical shock from the high voltages and currents present in the current ramping circuit <NUM> and the parallel resonant circuit <NUM>, the current ramping circuit <NUM> and the parallel resonant circuit <NUM> are galvanically isolated from the power source <NUM> by transformer <NUM>. The transformer <NUM> is provided with diodes <NUM> for rectification purposes. Therefore, the inductor <NUM> and other components of the parallel resonant circuit <NUM> are floating, and therefore safe to touch even if insulation surrounding the inductor <NUM>, cable <NUM> or other components is damaged.

To complete the isolation, the semiconductor switch <NUM> receives switching signals over a fibre optic cable <NUM> and the optional further switch <NUM> receives switching signals over a fibre optic cable <NUM>. This helps to reduce induced interference which might occur on an electrical link.

In the above description, it is described that the current I<NUM> in the PEMF device <NUM> comprises a sequence of decaying or damped sinusoidal oscillations. However, in alternative examples, the current I<NUM> may not necessarily comprise sinusoidal oscillations. In particular, the current I<NUM> may comprise a sequence of decaying or damped oscillations of a non-sinusoidal shape. For example, the current I<NUM> may comprise a sequence of decaying or damped oscillations having a square, triangular, saw-tooth, or any other shaped oscillating waveform. Consequently, it will be appreciated that pulsed EMF <NUM> may have a corresponding non-sinusoidal shape, as will the voltages induced across the coil loops <NUM> or <NUM>. Furthermore, the waveform shapes of the currents and light/ultrasound outputs of the light therapy device <NUM> and the ultrasound therapy device <NUM> will differ accordingly.

In the above description, it is described that the light therapy device <NUM> emits a light pulse having an intensity that is proportional to the energy or oscillations of the EMF pulse <NUM>. In other examples, the light therapy device <NUM> may emit a light pulse that has a fixed intensity or a predetermined intensity pattern, regardless of the shape of the EMF pulse. The conditioning circuitry <NUM> may be adapted accordingly to supply current to the light generating unit <NUM>, such that the light generating unit <NUM> emits the light pulse with a fixed intensity or predetermined intensity pattern.

In the above description, it is described that the diode D<NUM> of the light therapy device <NUM>, as shown in <FIG>, performs the function of a half-wave rectifier. In alternative examples, the diode D1 may be replaced by a different type of rectifier.

In some examples, the diode D1 may be replaced by a full-wave rectifier. For example, the full-wave rectifier may be a bridge-rectifier. In one example arrangement, the bridge-rectifier may have a first input terminal coupled to the terminal 123A of the coil loop <NUM>, a second input terminal coupled to the terminal 123B of the coil loop <NUM>, a first output terminal coupled to the first sides of the resistors RL1, and RS1, and a second output terminal coupled to second terminal 127B of the light generating unit <NUM>. The bridge-rectifier may comprise four diodes arranged between the input and the output terminals in a bridge-rectifier configuration. For example: an anode of a first diode is coupled to the first input terminal; a cathode of the first diode is coupled to the first output terminal; an anode of a second diode is coupled to the second output terminal; a cathode of the second diode is coupled to the first input terminal; a cathode of a third diode is coupled to the first input terminal; an anode of the third diode is coupled to the second output terminal; a cathode of a fourth diode is coupled to the second input terminal; an anode of the fourth diode is coupled to the second output terminal.

Alternatively, the full-wave rectifier may be a centre-tapped coil rectifier. In an example arrangement of the light therapy device that uses a centre-tapped coil rectifier, the coil loop <NUM> may be a centre-tapped coil that is inductively coupled with the coil loop inductor <NUM> of the PEMF device. A first, upper side of the centre-tapped coil is coupled to an anode of a first diode. A second, lower side of the centre-tapped coil is coupled to an anode of the second diode. Cathodes of the first and the second diodes are coupled together to form a first output terminal of the rectifier. A centre tap of the centre-tapped coil forms a second output terminal of the rectifier. The first output terminal is coupled to the first sides of the resistors RL1 and RS1. The second output terminal is coupled to the second terminal 127B of the light generating unit.

In some embodiments, the diode D<NUM> may be omitted. As such, with reference to <FIG>, the terminal 123A of the coil loop <NUM> may be coupled to the first sides of the resistors RL1 and RS1. The resistors RL1 and RS1 may receive an unrectified current from the coil loop <NUM>.

It will be appreciated that the diodes D2 and/or D3 of the light therapy device <NUM>' may be varied in accordance with the above variations discussed in respect of the diode D1. For example, the diode D2 and/or D3 can also be implemented as a type of rectifier different to a half-wave rectifier, such as any type of full-wave rectifier including those discussed above. Moreover, the diode D2 and D3 may be omitted. As such, with reference to <FIG>, the terminals 123A, 123A' and 123A" of the respective coil loops <NUM>, <NUM>' and <NUM>" may be coupled to the first sides of the resistors RS1 and RL1. The resistors RL1 and RS1 may receive an unrectified current from the coil loops <NUM>, <NUM>' and <NUM>".

It will be appreciated that other variations and alternative implementations discussed in respect of the light therapy device <NUM> may apply to the light therapy device <NUM>'.

Claim 1:
A pulsed electromagnetic field system comprising: a pulsed electromagnetic field, EMF, device configured to generate an EMF pulse; and a second device comprising: a first coil loop; and a light generating unit electrically coupled to the first coil loop, wherein the first coil loop is configured to induce a first current in response to the EMF pulse, and wherein the light generating unit is arranged to receive at least some of the first current and emit a light pulse having an intensity proportional to the received current;
characterised in that the second device comprises a second coil loop electrically coupled to the light generating unit, wherein the second coil loop is configured to induce a second current in response to the EMF pulse, wherein the light generating unit is arranged to receive at least some of the first current and the second current, wherein the first coil loop is arranged in a first plane and the second coil loop is in a second plane that is different to the first plane.