Patent Publication Number: US-2012038619-A1

Title: System and method for controlling inductive power to multiple modules

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT/IL2010/000209 filed Mar. 11, 2010, which claims the benefit of U.S. provisional application Ser. Nos. 61/202,554 filed Mar. 12, 2009; 61/202,555 filed Mar. 12, 2009; and 61/202,567 filed Mar. 12, 2009, and a continuation-in-part of U.S. Ser. No. 12/563,544 filed Sep. 21, 2009, which is a continuation of PCT application Serial No. PCT/IL2008/000401 filed Mar. 23, 2008, which claims the benefit of U.S. provisional application Ser. Nos. 60/907,132 filed Mar. 22, 2007, 60/935,847 filed Sep. 4, 2007, 61/006,076 filed Dec. 18, 2007, 61/006,106 filed Dec. 19, 2007, 61/006,488 filed Jan. 16, 2008 and 61/006,721 filed Jan. 29, 2008 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to methods and systems for controlling inductive power distribution to interchangeable electrical devices and controlling electrical devices such as display modules for displaying extended visual presentations over a surface. 
     BACKGROUND 
     Power may be transferred from inductive power outlets to inductive power receivers by electromagnetic induction. An inductive power outlet typically includes a primary inductor connected to a power source via a driver and an inductive power receiver typically includes a secondary inductor which may be connected to an electric load. Power may be transferred to the electric load by the driver applying an oscillating voltage across the primary inductor, which generates an associated variable magnetic field. When the secondary inductor is placed in the vicinity of the primary inductor&#39;s variable magnetic field an electric potential is induced thereacross. 
     Inductive power transfer systems are useful for providing versatile power distribution. Electrical devices connected to inductive power receivers may be moved from outlet to outlet without the need for connecting wires. However, their moving may lead to problems when controlling the power distribution. Whereas, in a hardwired system, electrical devices may be readily controlled centrally, it is not easy to centrally control electrical devices which are not tied to a single power outlet. 
     For example, a typical hardwired lighting circuit for a room may include a number of separate lamps each of which is controlled by a dedicated switch in a central switch board. In an inductive power distribution system, these lamps may be interchangeable so it is impractical to use a central controller wired to the outlets alone to control specific lamps. 
     It is further noted that large visual displays, used for example in roadside advertisements, are not typically dynamic. In general slogan bearing, static posters are simply pasted onto billboards situated at road sides near junctions and in other areas of high visibility. To alter such displays, such as to change the contents thereof, a different poster needs to be pasted up. Such billboards generally display the same advertisement for a few days or weeks at a time. 
     Electronic visual display units (VDUs), such as television sets and computer monitors for example, receive information as electrical signals and convert them for display as visual images on a screen. Many such display units consist of pixels, which are discrete optical elements. In Liquid Crystal Displays the optical states of these elements change in response to an electrical voltage applied thereacross. The optical characteristics, such as the polarization thereof, scattering angle and reflectivity of each pixel depend upon these optical states. By providing voltage selectively to each pixel of the display, a visual image may be constructed and displayed. 
     Although VDUs may be used for displaying actively changing advertisements, such advertising displays are generally smaller than billboards, have high installation and running costs. 
     There is therefore a need for an effective central control system for controlling power distribution to interchangeable electrical devices and which may be applicable to adjustable visual display systems. Further embodiments described herein address this need. 
     SUMMARY 
     Power may be transferred from inductive power outlets to inductive power receivers by electromagnetic induction. An inductive power outlet typically includes a primary inductor connected to a power source via a driver and an inductive power receiver typically includes a secondary inductor which may be connected to an electric load. Power may be transferred to the electric load by the driver applying an oscillating voltage across the primary inductor, which generates an associated variable magnetic field. When the secondary inductor is placed in the vicinity of the primary inductor&#39;s variable magnetic field an electric potential is induced thereacross. 
     Inductive power transfer systems are useful for providing versatile power distribution. Electrical devices connected to inductive power receivers may be moved from outlet to outlet without the need for connecting wires. However, their moving may lead to problems when controlling the power distribution. Whereas, in a hardwired system, electrical devices may be readily controlled centrally, it is not easy to centrally control electrical devices which are not tied to a single power outlet. 
     For example, a typical hardwired lighting circuit for a room may include a number of separate lamps each of which is controlled by a dedicated switch in a central switch board. In an inductive power distribution system, these lamps may be interchangeable so it is impractical to use a central controller wired to the outlets alone to control specific lamps. 
     It is further noted that large visual displays, used for example in roadside advertisements, are not typically dynamic. In general slogan bearing, static posters are simply pasted onto billboards situated at road sides near junctions and in other areas of high visibility. To alter such displays, such as to change the contents thereof, a different poster needs to be pasted up. Such billboards generally display the same advertisement for a few days or weeks at a time. 
     Electronic visual display units (VDUs), such as television sets and computer monitors for example, receive information as electrical signals and convert them for display as visual images on a screen. Many such display units consist of pixels, which are discrete optical elements. In Liquid Crystal Displays the optical states of these elements change in response to an electrical voltage applied thereacross. The optical characteristics, such as the polarization thereof, scattering angle and reflectivity of each pixel depend upon these optical states. By providing voltage selectively to each pixel of the display, a visual image may be constructed and displayed. 
     Although VDUs may be used for displaying actively changing advertisements, such advertising displays are generally smaller than billboards, have high installation and running costs. 
     There is therefore a need for an effective central control system for controlling power distribution to interchangeable electrical devices and which may be applicable to adjustable visual display systems. Further embodiments described herein address this need. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings. 
       With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention; the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings: 
         FIG. 1  is a block diagram representing the main components of a mated inductive pair according to one embodiment; 
         FIG. 2   a  is a schematic representation of a display system with interchangeable panels including inductive receivers configured to mate with inductive outlets according to another embodiment; 
         FIG. 2   b  shows an exploded schematic view of an interchangeable panel of the display system of  FIG. 2   a;    
         FIG. 3  is a schematic representation of an inductive power transfer system incorporated into a surface with a central control panel for controlling power provision to a variety of electrical devices, according to a further embodiment; 
         FIG. 4   a  is a flowchart of a method for mating an inductive power outlet and an inductive power receiver according to another embodiment; 
         FIG. 4   b  is a flowchart of a method for controlling power distribution in an inductive power distribution system according to still another embodiment; 
         FIG. 5   a  is a schematic exploded view of an embodiment of a display system constructed from a plurality of panels; 
         FIG. 5   b  is a block diagram showing the main elements of the display system according to another embodiment; 
         FIG. 5   c  is a block diagram showing the components of the visual display of the display panel incorporating a plurality of optically active pixels according to another embodiment; 
         FIG. 6  is a flowchart representing a method for providing an adjustable visual display according to still another embodiment; 
         FIG. 7   a  is a schematic representation of the main components of a system for remotely controlling a modular display from computer terminal connected to the internet according to another embodiment of the display system; 
         FIG. 7   b , is a schematic representation of a dot matrix which may be used to construct characters and images in the visual display according to various embodiments; 
         FIG. 8   a  is a block diagram of the main components of a display-master for use with embodiments of the display system; 
         FIG. 8   b  is a block diagram representing the main components of a display module for use with embodiments, and 
         FIG. 9  is a flowchart of a method for remotely controlling a display system according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Reference is now made to  FIG. 1  showing a block diagram of the main components of a mated inductive pair  10  according to one embodiment of the current invention. The inductive pair  10  consists of an inductive power outlet  20  and an inductive power receiver  30 . 
     The inductive power outlet  20  consists of a primary inductor  22 , such as a coil of wire or the like, wired to a power source  24  via a driving unit  23 . The driving unit  23  provides the electronics necessary for driving the primary inductor  22 . Driving electronics may include for example a switching unit for providing a high frequency oscillating potential across the primary inductor  22 . 
     The inductive power receiver  30  comprises a secondary inductor  32 . The inductive power receiver  30  comprises a secondary inductor  32  which may be coupled to an electric load  34  optionally via a rectifier  33  for converting the alternating current output of the secondary inductor  32  into a direct current supply to the load  34 . 
     It is a particular feature of embodiments of the present invention that the inductive pair  10  further consists of a signal transfer system  40 . The signal transfer system  40  includes a signal generator  42 , a transmitter  44  and a detector  46 . 
     The signal generator  42  generates a data signal Sd which is sent to the transmitter  44  for transmitting to the detector  46 . It will be appreciated that the transmitter  44  may be associated with either the power outlet  20  or the power receiver  30  as required. Thus communication of the data signal Sd may be provided either from the power outlet  20  to the power receiver  30  or from the power receiver  30  to the power outlet  20 . Indeed, where appropriate, bidirectional communication pathways may be provided. 
     Preferably, the power receiver  30  and power outlet  20  are both labeled with unique identifiers. The signal transfer system  40  may be used to communicate an identification label between the inductive power outlet  20  and the inductive power receiver  30 . Thus the inductive pair may be mated together by communicating the identity of the power receiver  30  to its associated power outlet  20  and/or communicating the identity of the power outlet  20  to the power receiver  30 . 
     Various embodiments of the invention use various transmitter-detector interfaces. For example an optical transmitter such as a lamp, a light emitting diode or the like, may be used to interface with an optical detector, such as a light dependent resistor, a light dependent transistor or the like. Alternative arrangements may use radio transmitter-receiver interfaces, audio transmitter-receiver interfaces, ultrasonic transducers-piezoelectric detector interfaces, optocouplers, coil-to-coil data transfer systems or such like. 
     In a particular preferred embodiment of the invention, the driving unit  23  applies a driving voltage across the primary inductor  22 , which oscillates at a transmission frequency higher than the resonant frequency of the system. A reception circuit is usefully wired to the primary inductor  22 . The reception circuit typically comprises a voltage monitor for monitoring the amplitude of the voltage across the primary coil. 
     A transmission circuit is likewise wired to the secondary inductor for sending a data signal to the reception circuit. In a specific embodiment of the transmission circuit, the signal generator is configured to generate the data signal by intermittently connecting at least one electric element to the secondary inductor  32  thereby increasing the resonant frequency. Each increase in the resonant frequency of the system may be detected by the reception circuit as a spike in the voltage monitored by the voltage monitor. Other signal transmission systems  40  may be preferred for use in other embodiments of the present invention as appropriate. 
     Interchangeable Display Panels 
     According to other embodiments of the invention, the mated inductive couple may be used in a power distribution system for providing power to a plurality of different electrical devices. Referring now to  FIGS. 2   a  and  2   b , one embodiment of a power distribution system  100  is presented. The system  100  provides a surface  112  having adjustable visual properties such that an image may be presented across multiple display panels  130 . The display panels  130  are interchangeable units  131 , having a visual output surface  134  wired to an inductive power receiver  132 . The panels  130  are adapted to be connected to the support structure  20  by some fastening means such as hooks, screws, pins, adhesives, magnets or the like. It is noted that in various embodiments of the invention, the system  100  may be used to provide, inter alia, adjustable decors for a room, interactive signs, electronic advertising billboards, stage scenery and the like. 
     A support structure  120 , such as a wall or a floor of a room for example, includes an array of inductive power outlets  122  connected to a power source via driving units  123 . Optionally, a plurality of inductive power outlets  122  are connected to common driving unit  123 . In a particular embodiment, suitable wire  125  is used to supply power to the driving unit, for providing a universal A.C. voltage between 90V and 240V, whereas 3 A conductors  127  may be suitable for distributing power to the power outlets  122 . In other embodiments alternative conductors may be selected as appropriate. 
     In certain embodiments of the display system  100  the display panels  130  further comprise individual receivers  135  configured to receive remote signals indicating the desired display for their associated panel. Thus, for example, a row of four panels  130   k ,  130   h ,  130   e ,  130   b  may each receive a separate signal indicating that they each display a letter T, I, L and E say, spelling the word TILE. 
     It is particularly noted that display panels  130  are essentially identical to each other and are thus readily interchangeable. In order that a desired image, the word TILE, say, is retained when two panels are interchanged, it is useful to mate the power receivers  132  hosted by the panels with the power outlets  122  on the support structure. Thus if the L-panel  130   e , mated to a first power outlet  122   e , were to be swapped with the T-panel  130   k , mated to a second power outlet  122   k , the power receiver  132  of the L-panel  130   e  would mate with the second power outlet  122   k  and the power receiver  132  of the T-panel  130   k  would mate with the first power outlet  122   e . As a result of its new location, the L-panel  130   e  would update its display to show a letter T and the T panel  130   k  would update its display to show a letter E. Thus the word TILE would remain unchanged. 
     Interchangeable Electrical Devices 
     According to other embodiments, interchangeable electrical devices may be associated with each power receiver.  FIG. 3  shows a power distribution system  200  consisting of an array of inductive power outlets  222  incorporated within a wall  210 . Interchangeable electrical devices  234 , such as a light fixture  234   a , a conductive power outlet socket  234   b  and a television  234   c , for example, are wired to inductive power receivers (not shown). 
     A central controller  226  is provided for switching power to the individual devices  234 . By mating the power receivers to specific power outlets  222 , a dedicated control switch  227  may be used to control a particular device  234 . A power receiver may send an identification code to a mated power outlet  222  associating it with a specific electrical device  234 . Consequently, when the dedicated control switch  227  sends a signal for controlling the specific electrical device  234 , say the light fixture  234   a , only the power outlet  222  mated with the light fixture  234   a , responds to the signal for example by activating or deactivating the primary inductor. Thus the light fixture  234   a  may be moved to another location and mated to another power outlet  222 , according to requirements yet the light fixture  234   a  may still be controlled centrally by the same dedicated power switch  227 . 
     In still further embodiments of the invention, a power distribution system involving mated inductive power outlets may be useful for example for wirelessly providing power to a plurality of stage lights controlled centrally by a lighting console. In another application, power may be provided to a plurality of microphones, amplifiers and the like inductively, avoiding the need for dangerous and unsightly trailing wires across a stage. By mating each inductive receiver to its current inductive outlet each unit may be controlled centrally whilst providing maximum mobility during a concert. Other applications of the invention will occur to those skilled in the art. 
     With reference to  FIG. 4   a  a flowchart is shown representing a method for mating an inductive power outlet with an inductive power receiver. The method comprises the following steps: labeling an inductive power outlet with a first identification code  401 , labeling an inductive power receiver with a second identification code  402 , providing a signal transfer system  403 , aligning a secondary inductor to a primary inductor  404  and communicating an identification signal between the inductive power outlet and the inductive power receiver  405 . 
     Referring to  FIG. 4   b , a flowchart of a further method for controlling power distribution to specific electric devices is presented. The method comprises the steps of: providing a plurality of labeled power outlets  406 , providing a controller for selectively connecting the labeled power outlets to a power source  407 , connecting the electrical device to a labeled inductive power receiver  408 , mating the inductive power receiver to one labeled inductive power outlet  409  and the controller connecting the mated power outlet to the power source  410 . 
     Modular Display Systems 
     As noted above in relation to  FIG. 2   a , the power distribution system is particularly suited to modular display systems. Reference is now made to  FIG. 5   a  showing a schematic exploded view of another embodiment of a modular display system  510  for generating an adjustable presentation upon a surface  512  according to one embodiment of the present invention. The surface  512  is constructed from an array of display panels  530  and blank panels  540  mounted upon a support structure  520 . 
     According to various embodiments of the invention, the system  510  may be used to provide, inter alia, adjustable decors for a room, interactive signs, electronic advertising billboards, stage scenery and the like. 
     The support structure  520 , such as a wall or a floor of a room for example, contains a power providing infrastructure including inductive power outlets  522  connected to a power source via driving units  523 . Optionally, more than one inductive power outlets  522  are connected to common driving unit  523 . In a particular embodiment, suitable wire  525  is used to supply power to the driving unit, for providing a universal A.C. voltage between 90V and 240V, whereas 3 A conductors  527  may be suitable for distributing power to the power outlets  522 . In other embodiments alternative conductors may be selected as appropriate. 
     In order to protect high voltage wires from environmental contaminants such as humidity, dust, salt and the like, in preferred embodiments, the power providing infrastructure is sealed from the environment. Other configurations of driving units  523  and power outlets  522 , which may further optimize the power providing infrastructure for power distribution, heat dispersion and the like will occur to the skilled electrical engineer. 
     Each display panel  530  includes a casing  531  containing an inductive power receiver  532 , an array of display drivers  533  and an adjustable visual display  534 . The appearance of the adjustable visual display  534  is configured to change when a driving signal is received from a display driver  533 . In preferred embodiments each display driver  533  is configured to drive a separate section  535  of the visual display  534 . The casing  531  is adapted to be connected to the support structure  520  by some fastening means such as hooks, screws, pins, adhesives, magnets or the like. 
     It is particularly noted that in embodiments of the invention, power is provided to the display panel via electromagnetic induction therefore there is no need for a conductive connection between the panel and the support structure. Optionally the casing  531  is sealed to protect the internal components from the environment. It will be appreciated that sealed casings  531  represent a particular advantage when the panels are exposed to the open air for example when mounted on a billboard, on the external surfaces of a building or the like. 
     The blank panels  540 , which may have the same size and shape as display panels  530  are optionally used to complete a surface  512  where it is unnecessary to fully cover the support structure with display panels. 
     The main elements of the display system  510  are presented in the form of a block diagram in  FIG. 5   b . The support structure  520  is wired to a power source  524  and includes a primary inductor  522 ′, which draws power from the power source  524  via an inductive driver  523 . The primary inductor  522 ′, such as an inductive coil or the like, is provided to inductively couple with a secondary inductor  532 ′ incorporated in the display panel  530 . The inductive driver  523  provides the electronics necessary to drive the primary inductor  522 ′. Driving electronics may include a switching unit providing a high frequency oscillating voltage supply, for example. Where the support structure  520  includes more than one primary inductor  522 ′, the driver  523  may additionally consist of a selector for selecting which primary inductor  522 ′ is to be driven. 
     The display panel  530  includes a secondary inductor  532 ′ configured to inductively couple with the primary inductor  522 ′ and to provide power to an array of display drivers  533 . Each display driver  533  is configured to provide a driving signal to control the visual appearance of a section  535  of the visual display  534 . Optionally, the display drivers  533  further include detectors  536  for receiving remote input determining the desired appearance of the associated section  535  of the visual display  534 . 
     In preferred embodiments a transmission-guard  521  is provided to prevent the primary inductor  522 ′ from being activated when no display panel  530  is present. Such a transmission-guard  521  may consist of a transmission-lock  521 L and a transmission-key  521 K. The transmission-lock  521 L is incorporated into the support structure  520  and connected in series between the power source  524  and the primary inductor  522 ′. The transmission-key  521 K is incorporated into the display panel  530  and unlocks the primary inductor  522 ′ when it is aligned with the secondary inductor  532 ′. 
     Preferably, the transmission-lock  521 L comprises at least one magnetic switch and the transmission-key  521 K comprises at least one magnetic element. In certain embodiments the magnetic element comprises a ferrite flux guidance core. Optionally, the transmission-lock  521 L comprises an array of magnetic switches configured to connect the primary coil to the power source only when activated by a matching configuration of magnetic elements. Typically, the magnetic switch comprises a magnetic sensor, such as a reed switch or Hall switch for example. 
     In other embodiments, the transmission-guard comprises: an emitter for emitting a release-signal and a detector for detecting the release signal; the transmission-key  521 K comprises at least one bridge for bridging between the emitter and the detector, such that when the secondary coil is brought into alignment with the primary coil the release signal is guided from the emitter to the detector. Optionally, the release-signal is an optical signal and the bridge comprises at least one optical wave-guide. Alternatively, the release-signal is a magnetic signal and the bridge comprises a magnetic flux guide. Alternatively, again, the release-signal is selected from the group comprising: mechanical signals, audio signals, ultra-sonic signals and microwaves. 
     It is noted that in preferred embodiments of the invention the display panels  530  may be readily interchangeable such that a faulty panel may be easily replaced. It will be appreciated that in such an embodiment, for a multi-panel image to be retained where panels have been interchanged some system must be provided to match each panel with its location. To this end it may be advantageous to provide a communication channel between the inductive outlet  520  and the inductive receiver  530  for communicating to each panel, its location upon the support structure. According to one embodiment a signal transfer system is provided for transferring data signals between the inductive power outlets and the inductive power receivers, which typically includes a signal generator for generating a data signal; a transmitter for transmitting the data signal, and a detector for detecting the data signal. 
     Reference is now made to the block diagram of  FIG. 5   c , representing an exemplary embodiment of the visual display  340  for use in a display panel  530  ( FIG. 5   a ). The visual display  340  typically consists of an array of pixels  342 . In preferred embodiments, after switching the states thereof, the pixels  342  are configured to retain their states and thus their appearance, even when no power is applied. Each pixel  342  includes an optical element  344  sandwiched between two electrodes  346   a ,  346   b  wired to a pixel driver  348 . The pixel drivers  348  are in communication with the display driver  533  which is configured to provide them with a driving signal as required. 
     The optical element  344  includes an optically active material, such as a liquid crystal, capable of assuming two or more physical states, the optical characteristics thereof, depending upon its state. The pixel driver  348  is configured to provide a switching voltage across the electrodes  346  such that when the switching voltage exceeds a predetermined threshold, the optical state of the optical element changes from a first optical state to a second optical state. For example, a switching voltage may cause a polarization effect, absorbing some of the light passing through liquid crystals such that the intensity of the light beam therethrough varies with the voltage. 
     According to some embodiments, the optical element may be a monostable material which is actively held in its second optical state for as long as the switching voltage is maintained above the threshold. A number of monostable display technologies are known in the art and include, for example scattering devices, twisted nematic devices (TN), super-twisted nematic devices (STN), vertically aligned nematic devices (VAN), in-plane switching (IPS), electrically controlled surfaces (ECS) and the like. 
     In preferred embodiments, the optical element is selected to be a bistable material in which the first optical state and the second optical state are both stable. In some bistable devices, the switching voltage switches the optical element from the first stable optical state to the second stable optical state and when the switching voltage is removed the second optical state is maintained. Indeed, where appropriate, it may be useful for the display to be configured such that once the optical state has been changed, the display disconnects autonomously. A number of bistable display technologies are known in the art and include, for example ferroelectric liquid crystal devices (FLC), BiNem devices, zenithally bistable devices (ZBD), post-aligned bistable displays (PABN), cholesteric liquid crystal devices (CLCD) and the like. 
     It is noted that any common pixel driving method as known may be used in conjunction with embodiments of the present invention. For example, in the segment driving method, shaped electrode segments may be are wired to dedicated pixel drivers and may be used to construct numbers, letters, icons and the like. 
     Alternatively, the matrix driving method constructs characters and images from a matrix of pixel dots, i.e. a pixilated array. The pixels of the matrix may be driven directly using dedicated pixel drivers in a manner similar to the segments of the segment driving method. However, if there are n rows and m columns, a direct driving method needs connections, and as the number of pixels is increased, the wiring of dedicated drivers becomes very complex. Thus the so called multiplex driving method may be preferred wherein the pixels are arranged at the intersections of vertical signal (“column”) electrodes and horizontal (“row”) scanning electrodes. Thus all the pixels across each row are connected together on one substrate and all the pixels in each column are connected on the opposite substrate. To switch a pixel, a voltage (+V) is applied to the row including that pixel, and then an opposite voltage (−V) is applied to the column including that pixel, with no voltage being applied to the columns which do not need to be switched. In consequence of this configuration, instead of requiring connections, the multiplex method only requires connections. 
     It will be appreciated that in applications where the electrodes and connecting wires would otherwise obscure the viewers line of sight to the optical element, it is advantageous to use electrodes constructed from a transparent conductive material such as indium tin oxide (ITO) for example. 
       FIG. 6  is a flowchart representing a method for providing an adjustable visual display according to still another embodiment of the invention. The method comprises the following steps: 
     (a)—providing at least one inductive power outlet comprising at least one primary inductor  601 ; 
     (b)—providing at least one inductive power receiver comprising: at least one secondary inductor for inductively coupling with the primary inductor; and at least one adjustable visual display, electrically connected to the secondary inductor via at least one display driver  602 ; 
     (optional) (c)—a detector receiving the control signal  603 , and 
     (d)—providing a display signal to the visual display thereby changing an appearance of the visual panel  604 . 
     Remote Controlled Displays 
     Reference is made to  FIG. 7   a  which schematically shows the main components of a system  71  for remotely controlling a modular display  710 . The system  71  includes a computer terminal  720  connected to the internet  730  and a modular display  710  in communication with a display engine website  732 . 
     The modular display  710  includes an array of display panels  712 A-I which are mountable on to a support structure  714 , such as a wall, or a floor of a room, for example. The display panels  712  may have various shapes and sizes. Optionally, similarly sized panels are configured to be interchangeable. Using panels in combination, an extended image spanning multiple display panels  712  may be presented. The modular display  710  is useful for providing, inter alia, adjustable decors for a room, interactive signs, electronic advertising billboards, stage scenery and the like. 
     The panels  714  include an array of display drivers  711  and an adjustable visual display  713 . The display drivers  711  are configured to send a driving signal to the visual display  713 . The visual display  713  is adapted such that its visual appearance is altered in response to the driving signal. In preferred embodiments each display driver  711  is configured to drive a separate section of the visual display  713 . 
     Each panel may be enclosed in a casing  716  which is adapted to be connected to the support structure  714  by some fastening means such as hooks, screws, pins, adhesives, magnets or the like. In preferred embodiments, the casing  716  further contains an inductive power receiver  717 , adapted to inductively couple with an inductive power outlet  715  mounted upon the support structure  714 . Accordingly, the support structure  714  may incorporate an array of inductive power outlets  715  connected to a power supply via driving units  719 . Optionally, more than one inductive power outlet  715  is connected to a common driving unit  719 . Where power is provided to the display panel via electromagnetic induction, there is no need for a conductive connection between a panel  712  and the support structure  714 . Consequently, the casing  716  may be sealed to protect the internal components of the display panel from the environment. It will be appreciated that sealed casings  716  represent a particular advantage when the panels are exposed to the open air for example when mounted on a billboard, on the external surfaces of a building or the like. 
     The computer terminal  720  may be connected to the internet  730  and may provide a user interface for controlling the visual output of the modular display  710 . In preferred embodiments, the user interface includes a visual representation  712 ′ of the modular display  710 , which is presented on the screen  722  of the computer  720 . The visual representation  712 ′ is divided into virtual panels A′-I′ which correspond to similarly shaped display panels A-I of the modular display  710 . The user interface typically provides further means by which a user may select an image for displaying on an individual panel  712  or over the whole or part of the modular display  710 . In some embodiments, the user interface may be a computer operable code stored upon the computer  720  as a plug-in application executable from a browser, an add-on application executable directly by the computer or the like. 
     The display engine  732 , which is usually hosted on a website, is adapted to receive remote signals from the user interface running on the computer terminal  720 . The display engine  732  is operable to resize the user selected image, to adjust its pixel resolution or otherwise to optimize the image for display upon the modular display  710 . The optimized visual configuration is communicated to a display master  718  controlling the modular display  710 . The communication channel from the display engine  732  to the modular display  710  may be via a direct cable connection, alternatively, an indirect communication channel may be provided via a communication device  734  such as a 3G telephone, for example. 
     Referring now to  FIG. 7   a , a dot matrix  7130  is shown which may be used to construct characters and images in the visual display  713  ( FIG. 7   a ) according to certain embodiments of the invention. The pixels  7132  of the matrix may be driven directly using dedicated drivers (in a manner known as segment driving method). However, if there are n rows and m columns, a direct driving method needs connections, and as the number of pixels is increased, the wiring of dedicated drivers becomes very complex. 
     Alternatively, the so called multiplex driving method may be used. The pixels are arranged at the intersections of vertical signal electrodes (or column electrodes)  7134  and horizontal scanning electrodes (or row electrodes)  7136 . Thus all the pixels across each row are connected together on one substrate and all the pixels in each column are connected on the opposite substrate. To switch a pixel, a voltage (+V) is applied to the row including that pixel, and then an opposite voltage (−V) is applied to the column including that pixel, with no voltage being applied to the columns which do not need to be switched. Thus instead of requiring connections, a multiplex method only requires connections. Typically, a separate voltage driver is connected to each of these connections, thereby requiring a total of voltage drivers. 
     It is feature of certain embodiments of the current invention, that a common voltage driver  7112 A,  7112 B is connected to multiple electrodes via individual switches  7116 A,  7116 B which are controlled by a MUX module  7114 A,  7114 B. Optionally, a first dedicated voltage driver  7112 A provides voltage to the column electrodes and a second voltage driver  7112 B provides voltage to the row electrodes, each with a separate MUX module  7114 A,  7114 B. Alternatively, a single voltage driver (not shown) may control all the connections. Still other configurations may be used to suit requirements. 
     Referring now to  FIG. 8   a , a block diagram is shown representing the main components of a display master  880  for use in various embodiments of the invention. The display master  880  includes a processor  882 , an internet cable communicator  884 , a cellular network communicator  886  and a module communicator  888 . 
     The display master  880  receives image data from the display engine website  832 . Image data may be received via a cable connected to the internet cable communicator  884  or via a communication device  834  connected to the cellular network communicator  886 . The processor  882  is configured and operable to distribute display data to the display panels  712  ( FIG. 7   a ) via the module communicator  888  such that each display panel A-I receives image data related to the section of the image appearing on the corresponding virtual panel A′-I′ of the visual representation  712 ′ ( FIG. 7   a ). Optionally, the display master  880  may be connected directly to an auxiliary computer  840  for maintenance or for initiation of the modular display  810  ( FIG. 7   a ), for example. 
     Referring now to  FIG. 8   b , a block diagram of the main components of a display module  820  for use in embodiments of the invention is shown. In an exemplary embodiment, the display module  820  includes a power receiver  822 , a signal communicator  824 , a memory  826 , a display driver  828  and a display screen  829 . 
     The power receiver  822 , which according to preferred embodiments includes a secondary inductor for receiving power from the support structure via induction, provides power for operating the display module as necessary. 
     The signal communicator  824  is configured to receive display data from the module communicator  888  ( FIG. 8   a ) of the display master  880  and to transmit feedback data to the master  880 . 
     The memory component  826  may store received data for sending to the display driver  828 . Optionally, the memory component  826  may store a plurality of data files for selectively displaying various images on the display panel. 
     According to one configuration, the memory component  826  comprises a plurality of external dual-port RAMs  827 . Optionally, RAMs may communicate with the signal communicator  822  via a bus and the signal communicator  822  is configured to read and write data to the memory  826 . Preferably, the memory is adjustable such that a user may add or remove RAM units from the bus as required. The bus may further connect with the display driver  828 . 
     In preferred embodiments, the display module  820  is labeled by a unique identifier and the identity of the display module  820  is communicated to the display master  880 . The unique identifier may, for example be a serial number in some readable form such as a bar code or the like. Alternatively, the unique identifier may be a digital code stored in the memory component  826  which may be transmitted via the communicator  824 . 
     Reference is now made to  FIG. 9  which shows a flowchart of a method for remotely controlling a display system according to an exemplary embodiment of the invention. The method includes the following steps: providing a plurality of display panels, each such display panel having a visual output displaying a section of a visual presentation  901 ; connecting each display panel to a common display master  902 ; the display master receives display data from a remote display engine  903 , and the display master controls the visual output of the display panels in response to the display data  904 . It is noted that this method may extend the method described hereinabove in relation to  FIG. 6 . In particular, it will be appreciated that the steps of the display master receiving data  903 , and controlling the visual output  904  may be considered substeps to step (d) of providing a display system  604  in the method of  FIG. 6 . 
     According to various embodiments of the invention, the modular display is operated as follows: A user attaches a display panel module to a support structure, for example by hanging it onto a wall. The modules are configured to automatically switch on and connect with the display master which may be connected to an auxiliary computer for initiation. The newly installed module is registered, and its size, shape and position are recorded. As further modules are attached and registered, a complete pattern of the display may be constructed on the auxiliary computer. The newly installed display structure is registered on the display engine website by uploading the pattern of the display structure alongside an identification code of the display master, such as a Mac address, IP address or domain name thereof. Once registered, the visual output of the display may be controlled remotely by computer terminals connected to the display engine website. 
     The system may be operable in a number of different modes such as an installation mode, an operational modes and a maintenance mode, as described hereinbelow. 
     Installation Mode 
     During installation of a new display configuration, a master may be connected to an auxiliary computer. As each display panel module is attached to the support structure, the module sends data relating to its size, shape and position to the master. The master is configured to relay this information to the auxiliary computer. These steps are repeated for all modules making up the display. Then the computer stores the modular pattern of the display including the shapes, sizes, locations and orientations of all the modules thereof. The modular display may be registered by uploading data relating to the modular pattern of the display to the display engine website, together with an identification code and an internet address for the master. Optionally, when the display is registered with the display engine, a Mac address is recorded in order to match the master to its corresponding display. It will be noted that the master of a display may be switched by changing the Mac address registered with the display engine. 
     It is noted that more than one modular display may be initiated simultaneously. It is therefore necessary that each module is matched to the correct master. In some embodiments this is achievable by printing a unique bar code for each module which may be read by the master before switching on the module so that the master will be the one that searches for the module. 
     It is further noted that a display should be accessible only by authorized users. This may be achieved, for example, by protecting access thereto with a password and a secure connection, such as SSL, TLS or the like. When connecting a module, the display may be further protected by requiring the matching of each module serial number to a password. 
     The communication between the master and the modules may be wireless whereas the connection and between the master and the auxiliary computer is generally via a connecting cable. The display engine may communicate with the master via a cellular communication device, such as a 3G network device or the like, which may be incorporated into the system. An additional communication channel may use a wired internet connection. 
     In some embodiments a visual feedback from the display to the display engine may be accessed via a remote controller. For example cameras directed towards the visual output of the display may be provided, the output thereof being relayed to the display engine. 
     Operational Mode 
     In operational mode a user may remotely control the modular sign from a computer terminal connected to the internet via the display engine. Typically, the user connects to the display engine website via a web browser. Alternatively a stand alone application may be executable on the user&#39;s communication device. 
     The user is preferably presented with a virtual representation of the modular pattern of the display. The visual output of the panel may be altered by selecting a desired image and arranging this image onto the modular pattern. The desired configuration is then uploaded to the display engine. The display engine is configured to process the image to suit the resolution of the display. For example 3 bytes of digital data may be matched to each pixel using a dynamic table. Furthermore, the display data may be separated into sub-units for distribution to individual display modules and sent to the master according to a site-master protocol. The user may have the option to send more then one image to the sign. When the display master receives display data, each sub-unit of data is sent to the corresponding display panel according to a master-module protocol. The display panel may be configured to save the data to a memory and when the data transmission finishes, may interrupt a MCU in the display driver. The display engine may also shut down a specific module, group of modules or even the complete display. 
     In some embodiments, a user may request feedback from the display. It is noted that website responses to such requests should have a frequency no higher than the frequency with which the display data is sent. In a first feedback configuration, automatic feedback is sent after each package of display data. The display master may broadcast a feedback request to the display modules. The modules receive the request, interrupt the MCU in the display driver and wait for a response. The display systems&#39; MCU then interrupts the operation system in the module and responds to the request. Data may be transferred from the display driver to the operation system according to the site-master protocol and the module may send a response to the master to be relayed to the display engine site. 
     According to a second feedback configuration, feedback is initiated by a display module. The display driver&#39;s MCU interrupts the operation system in the module and sends feedback. Data is then transferred from the display driver to the operation system, and the module sends data to the master which is relayed to the display engine site. In still a third feedback configuration, feedback is initiated by the user. The user requests appropriate feedback via the website and may decide whether to send the request to a specific module or to broadcast it to all the modules. 
     In a particular embodiment, the feedback signal is 32 bytes long and contains data relating, for example, to a failure notification, such as the kind of failure and the temperature of the module. The master may send feedback data containing a serial number of a module in case that module fails to response to the feedback request. The user may further change the number and the position of the modules at any time, and update such changes via the web site. 
     Typically, the display master is not connected to the auxiliary computer during operational mode. It is noted that the display engine is preferably compatible with receiving uploaded images from other communication devices such as a mobile telephone for example. 
     Maintenance Mode 
     In maintenance mode, a user has the option to bypass the display engine and control the display master directly using the auxiliary computer. The auxiliary computer may execute a stand-alone application having functionality similar to that of the display driver as well as that used during installation. For example the auxiliary computer may allow a user to operate the display master functions of installing and uninstalling modules, requesting feedback, sending control commands, sending images and the like. 
     Thus the various embodiments described hereinabove provide a power distribution system for controlling power to a plurality of outlets. The system is particularly useful for controlling interchangeable electrical devices and modular display units. The various embodiments are provided to illustrate the invention however, the scope of the present invention is defined by the appended claims and includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description. 
     In the claims, the word “comprise”, and variations thereof such as “comprises”, “comprising” and the like indicate that the components listed are included, but not generally to the exclusion of other components. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.