IL311848A - Light fixture based wireless optical power transmission system - Google Patents

Description

LIGHT FIXTURE BASED WIRELESS OPTICAL POWER TRANSMISSION SYSTEM FIELD The present disclosure describes technology related to the field of the wireless optical transmission of power from a base transmitter to a remote receiver, especially as applied to such a transmitter installed with its control equipment in a unit adapted to be inserted into a conventional light fixture socket.

BACKGROUND Optical wireless power transmission is well known, such as is described in commonly owned patent applications WO 2017/009854, for "A System for Optical Wireless Power Supply", WO 2017/033192 for "Wireless Power Distribution System", and WO 2017/179051 for "System for Optical Wireless Power Supply".

Such transmission systems generally include a transmitter unit capable of scanning the space in which the system is intended to supply the optical wireless power, and in which it is expected that mobile receivers requiring power will be found, and, once such a receiver has been located, transmitting a beam of optical power thereto. Such a transmitter unit is generally a self-contained dedicated unit that can be affixed to any convenient surface, and is most commonly located on a ceiling, such that its beam is not obstructed by objects or persons in the space, and thus can readily reach every part of the space being served by the transmitter unit within the intended range of the transmitter unit. Installation of such a system may be complex, requiring access to a power line in the ceiling, or installation of a new line if none is available in the vicinity. This normally requires a qualified electrical technician to implement.

The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.

SUMMARY The present disclosure attempts to provide novel systems and methods that overcome at least some of the disadvantages of prior art systems and methods. The present disclosure describes exemplary implementations of a novel optical wireless power transmission system incorporated into a lighting fixture that is removably attached to a ceiling or wall mounted socket, such that it is simple to install even by a layman, to such an extent that its installation is little different from the changing of a light bulb.

The optical wireless power transmitter unit is contained within a lighting fixture housing that has a standard electrical light fitting connector, such as an Edison screw, or a bayonet fitting, or any other standard light fitting connector. Consequently, it can be installed by simply inserting into a matching light socket mounted in the ceiling or high on a wall of the space in which it is to be used, and is powered by the existing AC mains power supply of that light fitting socket. Besides the optical power transmitter unit, the housing is fitted with a light source emitting essentially visible light, such that the device maintains its function of also supplying illumination to the space in which it is fitted.

However, a number of operational problems arise in such as system. 1. The most obvious problem is that using a single electrical connection point, namely a "two wire" connection at the light fixture socket, when the light is switched off, the optical wireless power transmission system will also be switched off. This is not desired, since the provision of optical wireless power should be available continuously, or at least largely continuously, independently of whether the light source is switched on or off. The term "largely continuously" is used since, other than for supplying receivers which do not have an internal storage device such as a battery or a capacitor, limited periods can be tolerated during which the supply of wireless power is interrupted. The length of the limited periods of cessation of service depends on the level of energy storage available in the receiver.

A number of different solutions are proposed in the systems of this disclosure in order to solve this issue, including: (a) The conventional light switch may be exchanged for a customized light switch which still has only a single connection to the light fixture socket, which is always energized when the light switch is ON, such that both the light source and the optical wireless power source in the device can remain operative, but which, according to the simplest implementation, includes a remote control link which operates only the light source on/off function from a single on/off toggle actuator on the light switch. Thus, while the transmitter unit and its associated control and ancillary circuits can remain on continuously, the light source can be turned on or off by the on/off toggle of the light switch, which controls only the light source, and sends the status of the switch by a remote control link. Since such a customized light switch should, according to the safety regulations in most jurisdictions, be installed by a professional electrician, or could be part of the electrical installation requirements of selected rooms in newly built or refurbished houses, an alternative solution enabling installation by non-qualified persons would be useful. Such an option could be provided by a cover unit adapted to be mounted over the conventional switch, the cover unit containing the remote control communication link for turning the light on or off by the new toggle in the cover unit, while the original toggle beneath the cover unit always remains on, to power the wireless power transmission system.

According to a second implementation, the optical wireless power transmission system incorporated into the lighting fixture may include a remote control unit with two switches, or two switch settings, one wirelessly used for actuating within the housing, power to the optical wireless power transmitter, and the other wirelessly actuating within the housing, the illumination sources, the desired requirements by the two switches being conveyed to the lighting fixture by means of the communication link.

In either of these two implementations, power is supplied to the combination lighting/power transmission fixture by a conventional lighting socket having only a two-wire supply, such that no changes are required to the wiring system of the room in which the combination fixture is to be used..

Furthermore, since the wall switch is not a source of power with a live and neutral wire, but is merely an Open/Close toggle switch located in one wire of the two-wire power line, the remote control unit needs energizing from a separate source. One method of achieving this is for the unit to be energized by the optical wireless power transmitted by the system, with or without an internal energy storage device in the unit. Alternatively, a replaceable battery power source could be used. (b) The system may be equipped with a storage battery that enables the transmission system to continue to operate for a predetermined time, even if the light has been switched off. (c) The system may be equipped with a warning signal that is activated when the light is switched off, and powered by the storage battery, acting as a reminder to the user to turn the light back on to maintain the supply of power to the transmitter unit and its ancillary circuits. The disadvantage of this solution is that it is merely a reminder, and that the light will need to remain on essentially continuously if the wireless power transmission should have essentially continuous availability, thus also rendering the use of the light switch as essentially superfluous. (d) The function of the light switch may be completely annulled, and separate control of the power to the wireless power transmission system and the lighting feature provided by means of a hand-held or wall mounted remote controller, such as is used on domestic air-conditioners and other installed devices. This solution would require permanent setting of the original wall switch in its closed (ON) position, to ensure a continuous supply of power to both the wireless power and the illumination aspects of the lighting fixture. The remote controller could be powered by a battery, as in other remote controllers, and in view of the intended use of the system, the battery could be a rechargeable battery using the power available from the wireless power transmission system. This solution is essentially what was described hereinabove in the second implementation of solution (a). 2. The system has to be designed so that the illumination from the light source does not interfere with the optical power transmission functionality. In particular, the power meter of the transmission system, which is essential for measuring the optical power transmitted, and optionally also the level of optical power retroreflected from a receiver localized by the system, should not be affected by the illumination emitted concurrently by the light source.

This can be achieved by using a specific geometry of placement, whereby the optical transmission system is in a separate enclosure, advantageously in the central region of the device, with the light source located in the peripheral region surrounding it. A beam blocking container wall, or a reflective wall, or any other suitable light blocking barrier, placed between the transmission system and the light system, may be incorporated to assist in achieving this requirement. 3. An associated problem that may arise by the presence of both a lighting system and a wireless transmission system installed in the same device or housing is that components of either system may block the other system’s field of view, this being more important for the wireless transmission aspect than for the illumination aspect, the later being less directional.

The geometry of component placing, as mentioned in item 2 above, should also solve this problem. 4. The illumination from the light source or sources should be diffused, since light sources may have a localized point from which the illumination is emitted, while the beam of optical power should be transmitted as a collimated beam without any diffusion.

This problem is solved by locating a diffuser in the system, to allow the light from the illumination source to go therethrough, whilst the beam from the wireless transmission system will go through an optically clear aperture.

. Another problem that exists using a standard light fixture such as an Edison screw, is that, unlike a rigidly mounted device, the position at which the device will come to its final position in the screw fitting, is not known, such that the angle at which the optical transmission unit is directed, relative to the room coordinates in which it is installed, is also not known.

This problem becomes unimportant for the implementations of the optical power transmission systems of the present disclosure, which are adapted to direct the beam towards mobile receivers which could move to any location in the reception space. This requires that the transmission system includes a beam deflector instructed by the system control to perform low power scanning of the reception area for such receivers. Based on a signal returned from the receiver to the transmitter, either as an optical retroreflected signal, or as an RF data signal transmitted to the transmission unit by means of a communication link, the location of the detected receiver can be determined. Such a scanning system is thus able to detect the angular orientation and angular azimuth of detected receivers without the need for any preliminary knowledge of the mounting orientation or height of the transmission unit mounted arbitrarily in the lighting fixture. 6. Finally, when the system is turned on after a period during which it was not energized, such a situation occurring only when first inserting the device, or if a power cut has occurred, safety considerations do not allow the system to begin operation in a high power, charging mode, since it is unclear in which direction the beam will be transmitted. Therefore, in such a situation, the system is mandated to begin operation in its low power scanning mode, until a receiver is located, at which point the power can be raised to its charging mode.

There is thus provided in accordance with an exemplary implementation of the devices described in this disclosure, a system for providing optical wireless power transmission into a space, the system comprising: (i) an external housing having a connector matched to fit into a standard lighting socket providing two-wire AC mains current, (ii) an AC/DC converter connected to receive at least part of the AC mains current from the connector, and to generate a DC current having a substantially lower voltage than the AC mains voltage, (iii) at least one first compartment adapted to contain at least one visible light illumination source, powered by current originating from the AC mains current input through the connector, (iv) a second compartment containing a laser power transmitter, comprising: (a) a laser device, adapted to emit a laser beam of infra red light, (b) a power meter positioned to measure the power of the laser beam, and (c) a beam steering device adapted to receive a signal input to direct the laser beam into desired direction, (v) an optically blocking shield disposed as a separation between the at least one first compartment and the second compartment, such that the power meter is shielded from light emitted from the at least one visible light illumination source in the at least one first compartment, and (vi) a controller powered by the DC current, the controller adapted to enable operation of the laser power transmitter in at least two modes: (d) a search mode in which the controller limits the laser beam power to a first level considered to be safe for human exposure thereto, and directs the beam steering device to scan the space for receivers, and (e) a charge mode, in which, after the system has detected a receiver, and the controller has commanded the beam steering device to lock the laser beam onto the receiver, the controller is enabled to raise the laser beam power to a second level, capable of supplying wireless power to the receiver, wherein the at least one visible light illumination source is adapted to be switched according to an externally supplied signal.

In such a system, the visible light illumination source may be powered either by AC mains current obtained from the connector, or by a DC current from the AC/DC power converter. On the other hand, the laser device should be powered by the AC/DC converter. Furthermore, the at least one first compartment may incorporate a diffusing window, such that the visible light emitted from the illumination source, is diffused before illuminating the space. The second compartment may incorporate an essentially transparent optical window, such that the laser beam undergoes minimal absorption and minimal distortion in its passage through the window. The beam shield between those two compartments may either have a reflective surface, or is an optically opaque beam blocker. Additionally, in any such systems, the externally supplied signal should enable the illumination source to be controlled without disconnecting power for the laser power transmitter. According to yet further implementations of the systems of the present application, the externally supplied signal may be any one of: (i) a wireless signal from a hand-held or wall mounted remote control unit, and input to the controller, (ii) a wireless signal from a wall mounted switch assembly, and input to the controller, or (iii) a mechanical signal generated by the action of a pull cord. In such systems, the wireless signal may be either an RF signal, or an infra red optical signal. In any of these systems, the wall mounted switch assembly may comprise a cover unit adapted to be installed over an existing light switch, and providing the externally supplied signal, such that the illumination source can be switched on and off while the power for the laser power transmitter provided from the light switch, is not interrupted. Furthermore, in any of the above described systems, the controller may be adapted to switch the laser power transmitter according to a second externally supplied signal. This second externally supplied signal may be provided by the hand-held or wall mounted remote control unit, or the wall mounted switch assembly. Additionally, the optically blocking shield should be configured to reduce to less than 0.1% the amount of visible light reaching the power meter in the second compartment, from the visible light illumination source in the at least one first compartment. Moreover, the laser beam may have a power of at least 100 mW of infra red light, and may contain less than mW of visible light. The visible light, on the other hand, should contain less than 100 mW of light in wavelengths between 1250 nm and 1550 nm, and furthermore, should be at a level of at least 2 W. According to yet another implementation, the system may further comprise an energy storage device, such that a notification signal can be provided to the user if power to the connector be disconnected. In such a case, the controller is configured to enable the visible light illumination source to continue operation if the power to the lighting fixture connector is interrupted. Additionally, such a system may be further configured to power the laser power transmitter from the energy storage device, in the absence of power from the connector.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: Fig.1 illustrates schematically an optical wireless power transmission device, including an illumination source, for insertion into a standard light socket, such that it can be installed by a layman; Fig. 2 illustrates schematically one exemplary wiring plan which enables switching on and off of the light in the device, without turning off the power supply to the optical wireless power transmission system, this capability being achieved without the need to make any changes to the wiring within the walls of the room or office; and Fig. 3 illustrates schematically an exemplary replacement switch unit for activating functions of the combination optical power transmission/lighting device, optionally mounted as a cover unit fitted over the conventional wall switch DETAILED DESCRIPTION Reference is first made to Fig. 1, which illustrates schematically an exemplary implementation of the systems of the present disclosure, showing an optical wireless power transmission system built into a housing 1 having an external protective shell, and which also includes one or more illumination sources 2A, 2B, emitting visible light for use in the area to be illuminated. The housing is similar to a light fixture housing, in that it has a standard light fitting connector 3 configured for insertion into a standard lighting socket, providing both the transmission system and the lighting source with its power. The electrical connection 3 can be an Edison screw or a bayonet fitting, or any other standard type of lighting fixture connection. As is conventional in such connectors, there are only 2 electrical contacts, thus providing connection for a single electrical circuit. A simple utilitarian form of housing 1 is displayed in Fig. 1, but it is to be understood that the housing could be made decorative and artistic, so long a sits operational functionality is not compromised.

The components and circuitry of a first embodiment of the system, are based on the preferred requirement that there should be no need to make any alterations to the wiring of the walls or ceiling of the space in which the system is to be used, thereby providing the advantage that no special installation is required in order to begin using the optical wireless power transmission system. It is to be understood though, that should such special installation work be readily implemented, such as during renovations, or in the case of new buildings where provisions for such special installation work may be readily made, the powering of the system can be simplified, and one option for achieving this option is described hereinbelow in a second embodiment.

The two functions of providing the laser beam for the optical wireless power transmission, and of providing illumination for the space in which the device is installed, as originally intended from the location of the lighting socket, should be disposed into separate compartments of the device, to avoid possible interference between them. The optical wireless power transmission section is advantageously located in a central compartment of the device, and should include the laser source 10, which is advantageously a laser diode fed by a laser driver circuit (not shown separately from the laser diode in Fig. 1), and its associated components for measuring and directing the laser beam 13, such as a power meter and a beam deflector 12 for scanning the beam 13 to any required location in the space. This central location enables the provision of adequate linear access to any required location in the space. The base of the device, facing the space into which the beam is to be projected, should be provided with an optical window 14, to protect the beam generating and propagating components from dust in the environment. The window should have minimal optical distortion or diffusion properties, and should have minimal absorption so as to be as transparent as possible to the wavelength of the laser beam. The lighting source 2A, 2B, on the other hand, can be conveniently positioned or dispersed in the area surrounding the central compartment, since the illumination from the lighting source does not require direct linear access to every part of the space. In that respect, circular, or at least partly circular lighting elements, whether one or more, may be used in the peripheral region surrounding the central compartment. The light source(s) should have a sufficient large solid angle of propagation of their illumination to illuminate the entire intended region of the space, or large regions of the space if more than one light source is used. Typically, the light is spread over a field of view of at least 0.1 Steradians. However it is to be understood that this arrangement is not intended to be limiting, and that other positional arrangements are also intended to be covered by the present disclosure. A diffuser window 4 should advantageously be provided between the light source or sources and the space in which the device is installed, both in order to eliminate any glare from localized light sources, but also to prevent any reflections of the light source with significant power levels, from being directed from objects in the room back towards the laser transmitter. A beam blocking wall 5, which could be reflective or optically opaque, is used to separate the inner laser transmission compartment from the outer compartment containing the visible illumination source or sources. This has the effect both of providing the laser beam generation components with its own sealed, protective compartment, but also of preventing interference because of leakage of the broadband illumination from the lamps 2A, 2B, into the laser compartment. Finally, since the output wavelength of the diode laser changes with changing temperature of the laser diode, and since the illumination sources may generate significant heat output besides the visible illumination, the lighting compartment may advantageously have an open top to enable the heat or more specifically, the hot air, to escape. Alternatively, or additionally, it may have a fan (not shown in Fig. 1) to generate an air flow to cool the compartment.

Since the cost of the wireless power transmission system is many times greater than the cost of lighting elements, and it is unfeasible to consider replacing the entire device because of the need to replace a bulb, the illumination sources should be replaceable, in the same way as conventional light sources are replaceable. Preferably smaller internal sockets (not shown in the schematic drawing of Fig. 1) such as the internationally designated E14 socket, may be used for the lighting sources.

Referring now to the power management and control features of the presently shown device of Fig. 1, the input AC mains power from the electrical connector 3, is first directed to a power hub 6, which directs the electrical currents to the various component functional subsystems of the device, according to the type of current required. (The mains power flow is shown in Fig. 1 by a single arrow indicating the direction of power flow, though in fact the current is conducted by a single pair of wires, one from and the other back to the connector.) Firstly, if the light source or sources 2A, 2B, are powered at the mains power voltage, the mains power should be applied directly to the light sources 2A, 2B, via the system controller 16, which uses an input instruction from the user, as will be further explained hereinbelow, to switch the mains power to the light source or sources, ON or OFF. Furthermore, the mains power is also input to an AC/DC converter 17, which outputs a low voltage DC current, usually at 5V DC, suitable for powering the laser source 10 and for applying the operating voltage to the various control and management circuits of the device. The output of the AC/DC converter may also be used to power the illumination sources, if they are low voltage types of sources. Alternatively, the illumination sources could be powered by a low voltage AC current provided by a suitable transformer (not sown in Fig. 1). The output of the AC/DC converter may also be directed to a battery or a super-capacitor, optionally provided as an energy storage device 18, such that the electronic management and control units can continue to operate even if the input mains power is inoperative. One such situation could be in an implementation where the room light switch is left operative in its normal manner, but the system incorporates a buzzer or another warning device, which indicates to the user when the switch to the lighting fixture has been switched off, to remind the user to switch it back on if the wireless power transmission is still required.

The controller 16 also functions as the system controller of the entire laser transmission system. In this role, it controls the level of current supplied by the laser driver to the laser diode 10, thereby adjusting the transmitted laser power from the device. The controller may use a signal proportional to the beam power measured by the power meter 11, in order to provide a feedback signal to the laser to stabilize its power at the level required. In a typical application, the laser transmission system can project the laser beam 11 into the space in two different modes. The initial mode is a search mode, in which the controller causes the laser beam to be scanned over the space at a first low power level, in order to detect remote receivers in the space which may require power. The power level is substantially below that of the main mode which the system will use for providing power to the remote receiver. The low power level ensures that, during the scanning mode, the system is operating in a mode which is safe to persons located in the space. The scanning is performed by the controller directed beam deflector 12, and is generally performed using a raster pattern, until a receiver is detected, which is usually achieved by detection of a retroreflected signal from the receiver back to the transmission device. A photovoltaic cell (not shown in Fig. 1) in the device may be used to monitor for the retroreflection. As an alternative, the impingement of the laser beam on the receiver photovoltaic cell may cause generation of a signal for transmission from the receiver along an RF communication link 7 back to the device, where it may be detected by one or more antennae 8 on the housing. The received signal is input to the controller 16, which, once the beam is confirmed to be centered on the photovoltaic cell of the receiver, is programmed to output an instruction to the laser 10 to switch the beam deflector 12 from the scanning mode to a receiver tracking mode, in which the controller typically uses a feedback of the beam impingement on the receiver PV to cause the beam deflector to carefully follow motion of the receiver. Secondly, the controller enables the output laser power to be raised to the high power level mode, at which it supplies the required power level to the receiver.

Another function of the controller 16, is to supervise the switching on or off of the illumination source 2A, 2B, according to the requests of the user. In that function, the controller receives an electronic signal that the user wishes to turn the illumination on or off, the signal being detected through a radio link from the remote wall switch control module. This control link is different from the communication link 7,8, used for the communication of data between the control unit 16 and a receiver, but could use either the same or a different antenna 8. When the controller receives such a light switch command, it either enables passage of light current from the power hub 6 to the light sources 2A,2B, turning the light(s) on, or it cuts off passage of current to the lamp(s), extinguishing the illumination. For those systems which are not equipped with such a command link facility between the wall switch and the light fixture, the controller can alternatively generate a signal for a warning device 19, such as a buzzer, a flashing light, an auditory notification, a vibration signal, or any other suitable warning, to remind the user that since the power to the light unit has been switched off, the power to the laser has also been switched off, and wireless charging power is now dependent on the time that the storage battery or capacitor can continue to provide power for the transmission. As a simpler control system for the lighting actuation, a simple, conventionally used pull-cord (not shown in Fig. 1) attached to the lighting fixture could be used to turn the light on or off, either by a directly operated mechanical on-off switch of the AC mains power to the lamp(s), or by providing a signal to the controller to perform the AC mains power switching for the lamp(s).

Reference is now made to Fig. 2 and Fig. 3, which illustrate schematically, exemplary ways in which the existing lighting circuitry of the room may be used in order to provide separate switching ability for the lighting aspect of the above described wireless power transmission device, without interfering with the provision of laser power transmission for providing charging or operational power to mobile electronic devices in the room.

Several options exist for achieving this aim. A simple option would be to provide a separate hand-held or wall mounted remote control unit, with an option of controlling both the wireless power transmitter, and the room illumination, as previously described. However, since a hand-held control unit often, may not be readily located by a person entering a dark room and needing to turn on the light, another possible solution is proposed having the advantage of using the familiarly positioned light switch on the wall immediately by the door. In this embodiment, the conventional light switch is converted into a wall light switch incorporating a wireless remote control system. In such a system, the light switch command is communicated to the combination wireless power/lighting device 21, in order to turn the light(s) on or off. Such a wall unit could either be a complete replacement for the conventional light switch, or, to enable installation by the user rather than a qualified electrician, the unit could be built into a cover module 24, which is fitted over the current conventional light switch 23, as clearly shown in Fig. 3, without the need to access any of the electrical leads into or inside the switch.

However, there is one problem that needs to be overcome in order to implement such a solution. In a conventional two-wire arrangement for a light socket 20, the live lead 28 from the AC mains supply 22, is routed down to the wall switch 23, where it is toggled to be either in a closed position (ON), in which case the live current can continue to the light socket 20, or it is open (OFF), in which case live current is cut off from the light socket, such that the light socket is unpowered. Consequently, if no rewiring of the room circuitry is envisaged, the conventional wiring arrangement shown in Fig,. 2, cannot be used to provide power for the electronic circuitry required for the remote control link in such an alternative light switch, since there is no access at the wall switch 23 to a source of power, meaning both a live and a neutral line. The conventional light switch 23 is merely an on/off circuit breaker. Therefore, power for such a combination light switch must be provided by an alternative means. A convenient and readily available power source is the wireless power transmission system itself, transmitting optical power 13 to the cover module switch unit 24, which may then include a storage battery. Other features of the system of Fig. 2, such as the communication link 27 and the photovoltaic cell PV, is explained in the more detailed drawing of Fig. 3.

Referring now to Fig. 3, there is shown a more detailed exemplary implementation of such a combination switch unit, optionally mounted as a cover module fitted over the conventional wall switch 23. The cover unit 24 may be installed by means of screws (not shown in Fig. 3) driven into the wall outside of the existing switch 23, or by screwing into the mounting screw holes of the original switch cover, or by any other suitable method. The cover unit may optionally include a protrusion 30, which maintains the toggle 29 of the original switch 23, in the ON position as soon as the cover unit 24 is mounted over the original switch 23.

Referring now to the cover unit 24 itself, it should contain a switching element 31, for turning the light on or off. The position of the switching element 31 is input to the switch controller which outputs a signal to the antenna 33, which accordingly transmits a wireless instruction 27 to the combination wireless power/lighting device 21 to turn the light on or off. The switch controller 32 may be powered by a battery 34, which could be either a replaceable battery accessed through a flap (not shown in Fig. 3) on the cover unit, or it could be a rechargeable battery which is kept charged by means of a DC/DC power supply 35, which receives its input from a photovoltaic cell 36, receiving optical power transmitted from the wireless power transmitter of the combination wireless power/lighting device 21.

Fig. 3 shows only one example of the components of such an additional cover unit providing remote control of the light switching function of the combination wireless power/lighting devices of the present application. However, it is to be understood that other implementations could be envisaged, such as a replacement switch cover, or an entire replacement switch, providing remote control of both the lighting and the wireless power transmission features of the combination wireless power/lighting device.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. Furthermore, it is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.

ABSTRACT An optical wireless power transmission system incorporated into a lighting fixture, that is easily installable. The optical wireless power transmitter unit is contained within a housing that has a standard electrical light fitting connector. Consequently, it can be installed by simply inserting into a matching light socket mounted in the ceiling or high on a wall of the room, and is powered by the existing AC mains power supply of that light fitting socket. The housing is further fitted with a light source, such that the device maintains its function of also supplying illumination to the room. Since the light socket has only a single current input capability, the wireless power transmitter functionality is maintained on, while the illumination functionality is switched ON and OFF by a remotely generated signal, such as from a remotely controlled hand held unit, or from a communication link in the switch.

Claims (20)

CLAIMS We claim:

1. A system for providing optical wireless power transmission into a space, the system comprising: an external housing having a connector matched to fit into a standard lighting socket providing two-wire AC mains current; an AC/DC converter connected to receive at least part of the AC mains current from the connector, and to generate a DC current having a substantially lower voltage than the AC mains voltage; at least one first compartment adapted to contain at least one visible light illumination source, powered by current originating from the AC mains current input through the connector; a second compartment containing a laser power transmitter, comprising: a laser device adapted to emit a laser beam of infra red light; a power meter positioned to measure the power of the laser beam; and a beam steering device adapted to receive a signal input to direct the laser beam into desired direction; an optically blocking shield disposed as a separation between the at least one first compartment and the second compartment, such that the power meter is shielded from light emitted from the at least one visible light illumination source in the at least one first compartment; and a controller powered by the DC current, the controller adapted to enable operation of the laser power transmitter in at least two modes: (i) a search mode in which the controller limits the laser beam power to a first level considered to be safe for human exposure thereto, and directs the beam steering device to scan the space for receivers, and (ii) a charge mode, in which, after the system has detected a receiver, and the controller has commanded the beam steering device to lock the laser beam onto the receiver, the controller is enabled to raise the laser beam power to a second level, capable of supplying wireless power to the receiver, wherein the at least one visible light illumination source is adapted to be switched according to an externally supplied signal.

2. A system according to claim 1, wherein the visible light illumination source is powered either by AC mains current obtained from the connector, or by a DC current from the AC/DC converter.

3. A system according to either of the previous claims, wherein the laser device is powered by the AC/DC converter.

4. A system according to any of the previous claims, wherein the at least one first compartment incorporates a diffusing window, such that the visible light emitted from the illumination source, is diffused before illuminating the space.

5. A system according to any of the previous claims, wherein the second compartment incorporates an essentially transparent optical window, such that the laser beam undergoes minimal absorption and minimal distortion in its passage through the window.

6. A system according to any of the previous claims, wherein the beam shield either has a reflective surface, or is an optically opaque beam blocker.

7. A system according to any of the previous claims, wherein the externally supplied signal enables the illumination source to be controlled without disconnecting the power for the laser power transmitter.

8. A system according to any of the previous claims, wherein the externally supplied signal is any one of: a wireless signal from a hand-held or wall mounted remote control unit, and input to the controller; a wireless signal from a wall mounted switch assembly, and input to the controller; or a mechanical signal generated by the action of a pull cord.

9. A system according to claim 8, wherein the wireless signal is either an RF signal, or an infra red optical signal.

10. A system according to either of claims 8 and 9, wherein the wall mounted switch assembly comprises a cover unit adapted to be installed over an existing light switch, and providing the externally supplied signal, such that the illumination source can be switched on and off while the power for the laser power transmitter provided from the light switch, is not interrupted.

11. A system according to any of the previous claims, wherein the controller is adapted to switch the laser power transmitter according to a second externally supplied signal.

12. A system according to claim 11, wherein the second externally supplied signal is provided by the hand-held or wall mounted remote control unit, or the wall mounted switch assembly.

13. A system according to any of the previous claims, wherein the optically blocking shield is configured to reduce to less than 0.1% the amount of visible light reaching the power meter in the second compartment, from the visible light illumination source in the at least one first compartment.

14. A system according to any of the previous claims, wherein the laser beam has a power of at least 100 mW of infra red light.

15. A system according to any of the previous claims, wherein the laser beam contains less than 5 mW of visible light.

16. A system according to any of the previous claims, wherein the visible light contains less than 100 mW of light in wavelengths between 1250 nm and 1550 nm.

17. A system according to any of the previous claims, wherein the visible light is at a level of at least 2 W.

18. A system according to any of the previous claims, wherein the system further comprises an energy storage device, such that a notification signal can be provided to the user if power to the connector be disconnected.

19. A system according to claim 18, wherein the controller is configured to enable the visible light illumination source to continue operation if the power to the lighting fixture connector is interrupted.

20. A system according to claim 18, further configured to power the laser power transmitter from the energy storage device, in the absence of power from the connector.