Abstract:
The present invention transforms existing electrical wall outlets into an emergency lighting system for homes, hospitals, hotels, nursing homes and businesses. The lighting device, designed as a replacement electrical wall outlet or receptacle, simply plugs into an existing dual outlet after removal of its faceplate. The lighting device continues to function as an electrical outlet, however, also comprises a local power source such as a constant charge lithium ion battery; a motion sensor for initiating a low level of lighting for darkened room or corridor transit; a power sensor for activating a high level of light when electrical service is disrupted, thereby broadcasting a wash of light over an otherwise darkened room or corridor; and a photoelectric cell which detects daylight or otherwise provided lighting of the room or corridor and thereby prevent unnecessary power usage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims priority to U.S. Provisional Application. No. 60/510,915 filed Oct. 14, 2003; the contents of which are incorporated herein in their entirety. 

   FIELD OF THE INVENTION 
   The present invention relates generally to the field of illumination and, more particularly, the invention relates to a solid state lighting source such as a light-emitting diode (LED) device that provides for multi-level, motion sensitive illumination in emergency situations. 
   BACKGROUND OF THE INVENTION 
   Frequently, homes, offices and industrial plant facilities experience many types of emergency situations involving power failures where an interior or exterior area has no light. Such power failures may result from electrical short circuits, brownouts, fire, accidents, natural disasters (i.e., floods, hurricanes, tornados, etc.) or a planned shutdown of electricity within a facility or dwelling. Many facilities, and especially residential homes, do not have emergency generators to provide temporary backup lighting in such situations and thus are limited to nominal emergency lighting in the form of portable light sources, such as flashlights or lanterns. 
   Accordingly, a need exists to provide a device for automatic, high-level illumination that is capable of immediate activation in response to a disruption of power. In such emergency situations, it is desirable for the illuminating device to be efficiently powered by a single battery pack, such that it is capable of constant high-level illumination lasting for several days or even weeks. Further, the illuminating device should provide a low-level illumination in response to local motion so as to facilitate the non-emergency transit of a darkened room or corridor. Finally, the illuminating device should be responsive to ambient light such that the above high and low-level illuminations do not occur in daylight or otherwise externally lighted rooms. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention transforms existing electrical wall outlets into an emergency lighting system for homes, hospitals, hotels, nursing homes and businesses. The lighting device, designed as a replacement electrical wall outlet or receptacle, simply plugs into an existing wall outlet. Alternatively, the device may provide a stand-alone unit that replaces a conventional wall outlet receptacle altogether. In either case, the lighting device continues to function as an electrical outlet; however, the device also comprises a local power source such as a constant charge lithium ion battery; a motion sensor for initiating a low level of lighting for transiting a darkened room or corridor; a power sensor for activating a high level of light when electrical service is disrupted, thereby broadcasting a wash of light over an otherwise darkened room or corridor; and a photoelectric cell which detects daylight or otherwise externally provided lighting of a room or corridor thereby preventing unnecessary power usage. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
       FIG. 1  illustrates a front perspective view an emergency lighting device in accordance with one embodiment of the present invention; 
       FIG. 2  illustrates a side view of an emergency lighting device, in accordance with an embodiment of the present invention; 
       FIG. 3  illustrates a schematic drawing of a front perspective view of an emergency lighting device, in accordance with another embodiment of the present invention; 
       FIG. 4  illustrates an electrical schematic drawing of one embodiment of lighting circuitry, in accordance with the present invention; 
       FIG. 5  depicts a flow diagram of a method for implementing an emergency lighting system, responsive to local motion and power disruption in accordance with one embodiment of the present invention; 
       FIG. 6  depicts a flow diagram of another method for implementing an emergency lighting system, responsive to local motion and power disruption in accordance with another embodiment of the present invention; and 
       FIG. 7  illustrates a schematic view a dedicated emergency lighting device in accordance with one embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     FIGS. 1 and 2  depict front and side perspectives of a lighting device in accordance with one embodiment of the present invention. According to the depicted embodiment, the lighting device  10  includes a main body housing  20  having a plug-through electrical capability for use in combination with a conventional electrical wall outlet (not shown). In one embodiment, the lighting device  10  is simply plugged into the wall outlet after removal of its faceplate. In other embodiments, the faceplate need not be removed as will be apparent to one of ordinary skill in the art. To facilitate this plug-through electrical capability, various embodiments of the device  10  include a plurality of female electrode receptacles  50  and male electrode prongs  55  that are disposed on opposing exterior surfaces of the main body housing  20 , as illustrated by  FIGS. 1 and 2  respectively. In various embodiments, the lighting device  10  also includes at least one array of light emitting diodes (LEDs)  30 , a power sensor  42 , a motion sensor  40 , and a photo sensor  45  attached to the main body housing  20 . These components are provided in electrical communication via corresponding electrical circuitry. 
   As will be apparent to one of ordinary skill in the art, the male electrode prongs  55  discussed above are configured for insertion into a standard electrical outlet thereby tapping into the main power supply of a building, home or other dwelling. Accordingly, the external plugs of other electrical appliances (not shown) may be inserted into the female electrode receptacles  50  of the lighting device  10 , which are electronically connected to the male electrode prongs  55 , thereby providing plug-through access to the main power supply for the other electrical appliances. Although depicted in  FIGS. 1 and 2  as having a standard United States outlet configuration, the plurality of electrode prongs  55  and corresponding female electrode receptacles  50  may be provided in any configuration currently known in the art, making the present invention useful for grounded, ungrounded, United States or international style outlets. Further, in other embodiments of the invention, the lighting device  10  may serve as an adapter having electrode prongs  55  of one configuration (e.g., standard United States configuration) opposed by female electrode receptacles  50  of another (e.g., standard European configuration). 
   Various embodiments of the present invention may include a local energy source  25  mounted to the circuit board  35  for providing energy to the array of LEDs  30 . In one embodiment, the local energy source  25  may be comprised of an electrochemical device, such as a battery pack. In various other embodiments, other energy sources may supply the electrical energy necessary to operate the lighting device of the present invention. For example, other direct current electrical sources such as solar power may be implemented or alternating current sources may be used. The choice of the electrical energy source will typically be dictated by ease of use, reliability concerns and the desired function (i.e., emergency versus temporary use) of the lighting device. 
   Referring to  FIG. 3 , a schematic drawing is provided illustrating a lighting device  10  according to one embodiment of the present invention. According to the depicted embodiment, the lighting device  10  includes an electronic circuit board  35  for supporting and electronically connecting at least one array of LEDs  30 , a power sensor  42 , a photo sensor  45 , and a motion sensor  40 . In various embodiments, these sensors combine to provide effective emergency lighting to a darkened room or corridor as described in detail below. 
   In one embodiment, a control circuit  37  may be provided wherein the power, photo and motion sensors  42 ,  45 ,  40  provide inputs to the control circuit  37 , which selectively engages the LEDs  30  to operate in either a rest mode, a low level luminance mode, or a high level luminance mode. In various embodiments, the control circuit  37  may include a processor, CPU, chip, or other similar logic employing element (not shown). The photo sensor  145  provides an input to the control circuit  37 , for selectively engaging the LEDs  30 . According to this embodiment, the photo sensor  45  provides a lit/unlit status signal to the control circuit  37 , based upon whether externally provided light is present proximate to the photo sensor  45 . If ambient light is sensed, a lit status signal is sent to the control circuit  37 , which thereby engages the LEDs  30  to operate in a rest mode, wherein the device  10  lies dormant until the ambient light drops below a selected level. At this nominal level of ambient light, the photo sensor  45  sends an unlit status signal to the control circuit  37 , which may engage the LEDs  30  depending upon the additional sensor inputs discussed below. 
   In another embodiment, a power sensor  42  provides an on/off signal to the control circuit  37 , based upon a sensed main power supply disruption. If a main power supply disruption is present, an “off” signal is sent by the power sensor  42  to the control circuit  37 , which thereby engages the LEDs  30  to operate in a high level luminance mode or a low level luminance mode depending on motion sensor input as discussed below. The high level luminance mode provides the maximum possible lighting to the darkened room or corridor. At this maximum level, full use of the local energy source  25  is required; thus, in embodiments using battery packs, battery life is exhausted at a maximum rate. Advantageously, however, even at this maximum exhaustion rate, the LEDs  30  of the present invention may consume as much as 90 percent less energy than standard incandescent light bulbs, thereby increasing expected battery life from a few hours to several weeks. If no main power disruption is sensed, an “on” signal is sent by the power sensor  42  to the control circuit  37 , and the LEDs  30  remain unengaged in a rest mode pending further input as discussed below. 
   In another embodiment, a motion sensor  40  provides an active/non-active signal to the control circuit  37  based upon sensed local movement. If local movement is sensed and the main power supply has not been interrupted, an “active” signal is sent by the motion sensor  40  to the control circuit  37 , thereby engaging the LEDs  30  into a low level luminance mode. The low level luminance mode provides moderate lighting of the darkened room or corridor. During the low level luminance mode, only a minimum level of battery power is required; thus battery life is exhausted at a minimum rate. If local movement is sensed and the main power supply has been interrupted, the active signal triggers the control circuit  37  to engage the LEDs  30  in the high level luminance mode described above. If no local movement is sensed and the main power supply has been interrupted, a “non-active” signal is sent by the motion sensor  40  to the control circuit  37 , thereby engaging the LEDs  30  in the low level luminance mode to conserve battery life. Further discussion in this regard is provided relating to various additional embodiments described below. 
   In another embodiment, at least one reflector  60  is positioned proximate to the array of LEDs  30  as illustrated in  FIG. 3 , for reflecting light in desired directions. As such, the geometric relationship between the LED elements  30  and the reflector  60  aids in dispersing the light, resulting in a lighting device  10  that is capable of broadcasting a wide-area blanket of light up appending walls or off of ceilings so as to properly illuminate a darkened room or corridor. 
     FIG. 4  provides a detailed circuit diagram of an electrical circuit board  135  in accordance with another embodiment of the present invention. According to the depicted embodiment, the lighting device includes an electrical circuit comprising an AC/DC converter  115 , a power sensor  142 , a motion sensor  140 , a photo sensor  145 , a battery charging control circuit  122 , one or more rechargeable batteries  125 , one or more LED arrays  130 , and a DC/DC constant current supply unit  160 . The above components combine to provide emergency lighting functionality by engaging one or more LED arrays between a rest mode, a low level luminance mode, and a high level luminance mode as referenced above. 
   In the depicted embodiment, the AC/DC converter  115  includes a UL listed high voltage capacitor C 1  in addition to diodes D 1 , D 2 , capacitors C 2 , C 3 , and resistor R 1 . A switch PNP transistor  123  is provided and controlled by the battery charging control circuit  122 . The battery charging control circuit  122  compares a reference voltage provided by a diode Z 1  to the voltage supplied by the one or more batteries  125 . If the battery voltage is low, the battery charging control circuit  122  sets the switch PNP transistor  123  to a closed status, whereby the batteries are charged. If the battery voltage is not low, the switch PNP transistor  123  is set to an open status and the batteries are not charged. 
   In one embodiment, the power sensor circuit  142  combines with the photo sensor circuit  145  to control the status of a second switch PNP transistor  150 , which functions to turn on/off the at least one array of LEDs  130 . In the depicted embodiment, if A/C power is absent and the photo sensor  145  detects a low ambient light condition, the voltage supplied to the power sensor circuit  142  will remain low and, thus, the power sensor circuit  142  closes the second switch PNP transistor  150 , thereby engaging the one or more LED arrays. If A/C power is present and/or the photo sensor  145  detects an acceptable ambient light condition, the voltage supplied to the power sensor circuit  142  will remain high and, thus, the power sensor circuit  142  opens switch PNP transistor  150  thereby turning off the one or more arrays of LEDs. 
   In another embodiment of the present invention, a DC/DC high efficiency converter  160  is provided to supply constant electrical current for driving the one or more LED arrays  130 . Additionally, the DC/DC converter  160  helps to maximize illumination time and also ensures that the LED brightness remains generally constant, despite any battery voltage decline experienced during use. In circumstances where brightness control is desired, e.g., to save battery life in non-occupied rooms, a brightness circuit  155  is provided for driving the LEDs arrays  130  between a high level luminance mode and a low level luminance mode. In various embodiments, a motion sensor  140  is provided for controlling the brightness circuit  155 . In one embodiment, the motion sensor  140  is a passive infrared motion detector having a Fresnel lens as known in the art. If no motion is provided adjacent the motion sensor  140 , the sensor  140  will engage the brightness circuit  155  to operate the LEDs in low luminance mode. If motion is present, the sensor  140  engages the brightness circuit  155  to operate the LEDs in high level luminance mode. Thereafter, if motion proximate the motion sensor  140  ceases, various embodiments may include a timing device as known in the art for triggering the LEDs to return to the low luminance mode after a selected period of time. In this regard, battery life may be maximized. In various other embodiments, one or more test switches  170  may be provided for testing the operation of one or more of the above circuits and/or LED arrays. 
     FIG. 5  illustrates a method for implementing an emergency lighting system having motion and power disruption responsiveness, in accordance with one embodiment of the present invention. The depicted method embodiment also provides nighttime motion sensitivity regardless of the power or motion conditions as described below. According to this embodiment, the method comprises the step of sensing ambient light  200  via a photo sensor to determine whether externally provided lights in a given room or corridor are operating. If external lights are operating or daylight is present, a rest mode step  205  is triggered. If ambient light is not sensed, the method further comprises the step of sensing local movement  210  via the motion sensor. If local movement is not present, a step of engaging the LEDs to operate in a low level luminance mode  215  is triggered, thereby providing nighttime motion sensitive illumination. If local movement is present, the method further comprises the step of sensing a main power supply  220 . If the main power supply has been interrupted and local movement is present, a high luminance LED step  225  is triggered. If the main power supply is uninterrupted and local movement is present, the LEDs are engaged to operate in a low level luminance mode  215 . 
   For purposes of further illustration, Tables 1 provided below outline the conditions for illumination according to various embodiments of the invention. In particular, Table 1 outlines the conditions for nighttime sensitive operation in accordance several embodiments of the invention. The presence of ambient light, local motion or external power is illustrated by a check-mark (“√”) and the absence of such conditions is illustrated by a dash (“−”). 
   
     
       
             
           
             
             
             
             
           
         
             
               TABLE 1 
             
           
           
             
                 
             
             
               Nighttime Sensitivity Enabled 
             
           
        
         
             
               Motion 
               Light 
               Power 
               Illumination Mode 
             
             
                 
             
             
               — 
               — 
               — 
               Low level illumination 
             
             
               — 
               — 
               ✓ 
               Low level illumination 
             
             
               — 
               ✓ 
               — 
               Rest mode 
             
             
               — 
               ✓ 
               ✓ 
               Rest mode 
             
             
               ✓ 
               — 
               — 
               High level illumination 
             
             
               ✓ 
               — 
               ✓ 
               Low level illumination 
             
             
               ✓ 
               ✓ 
               — 
               Rest mode 
             
             
               ✓ 
               ✓ 
               ✓ 
               Rest mode 
             
             
                 
             
           
        
       
     
   
   In various other embodiments, the above method may further comprise a step of returning the LEDs to a low level luminance mode  230  after a predetermined “no movement” time interval following step  225  as shown. In this regard, the emergency lighting device preserves battery life when the room or corridor is unoccupied. In alternate embodiments, the lighting device may be placed in electrical communication with one or more smoke detectors such that the above power-down step  225  may be overridden if the room or corridor fills with smoke, thereby potentially disturbing the ability of the motion sensor to detect local movement. Finally, in several embodiments of the present invention, the emergency lighting system is designed to loop so as to repeat the above-described method indefinitely upon activation. 
     FIG. 6  illustrates another method for implementing an emergency lighting system having motion and power disruption responsiveness in accordance with another embodiment of the present invention. The embodiment illustrated in  FIG. 6  removes the above described nighttime motion sensitivity in order to limit non-emergency power consumption. According to this embodiment, the method comprises the step of sensing ambient light  300  via the photo sensor to determine whether externally provided lights in a given room or corridor are operating. If external lights are operating or daylight is present, a rest mode step  305  is triggered. If ambient light is not sensed, the method further comprises the steps of sensing local movement  310  via the motion sensor. If local movement is present, the method further comprises the step of sensing a main power supply  320 . If no local movement is present, a similar step of sensing a main power supply  325  is triggered. If there has been no movement and the main power supply has been interrupted, a low level luminance mode  330  is triggered. A low level luminance mode is also triggered if there has been movement and the main power supply remains uninterrupted. If there has been movement and the main power supply has been interrupted, a high luminance LED step  335  is triggered. Further, if there has been no movement and the main power supply remains available, a rest step  305  is triggered. 
   For purposes of further illustration, Tables 2 provided below outline the conditions for illumination according to various embodiments of the invention. In particular, Table 2 outlines the illumination conditions for those embodiments wherein nighttime sensitivity has been disabled. The presence of ambient light, local motion or external power is illustrated by a check-mark (“√”) and the absence of such conditions is illustrated by a dash (“−”). 
   
     
       
             
           
             
             
             
             
           
         
             
               TABLE 2 
             
           
           
             
                 
             
             
               Nighttime Sensitivity Disabled 
             
           
        
         
             
               Motion 
               Light 
               Power 
               Illumination Mode 
             
             
                 
             
             
               — 
               — 
               — 
               Low level illumination 
             
             
               — 
               — 
               ✓ 
               Low level illumination 
             
             
               — 
               ✓ 
               — 
               Rest mode 
             
             
               — 
               ✓ 
               ✓ 
               Rest mode 
             
             
               ✓ 
               — 
               — 
               High level illumination 
             
             
               ✓ 
               — 
               ✓ 
               Rest mode 
             
             
               ✓ 
               ✓ 
               — 
               Rest mode 
             
             
               ✓ 
               ✓ 
               ✓ 
               Rest mode 
             
             
                 
             
           
        
       
     
   
   In various other embodiments, the above method may further comprise a step of returning the LEDs to a low level luminance mode  330  after a predetermined “no movement” time interval following step  335  as shown. In this regard, the emergency lighting device preserves battery life when the room or corridor is unoccupied. In alternate embodiments, the lighting device may be placed in electrical communication with one or more smoke detectors such that the above power-down step  225  may be overridden if the room or corridor fills with smoke, thereby potentially disturbing the ability of the motion sensor to detect local movement. Finally, in several embodiments of the present invention, the emergency lighting system is designed to loop so as to repeat the above-described method indefinitely upon activation 
   The above method steps have been provided in a sequence selected merely for illustration purposes. As will be apparent to one of ordinary skill in the art, alternate sequencing of the steps outlined above are possible without deviating from the inventive concepts set forth above. 
     FIG. 7  depicts a schematic view of a lighting device in accordance with yet another embodiment of the present invention. According to the depicted embodiment, the dedicated lighting device  415  includes a main body plate  422  which replaces altogether a conventional electrical wall outlet receptacle (not shown). The dedicated device  415  simply attaches to the power wire  468 , ground and neutral wires  466  of a conventional outlet structure  463 . Alternatively, a dedicated outlet structure (not shown) may be used that is sized to precisely match the structure of the dedicated device  415 . Once the dedicated device  415  has been electrically attached, it is affixed to the outlet structure  463  via attaching fasteners (not shown) that extend through mounting holes  465  in the main body plate  422 . As described above, the dedicated device  415  similarly includes a plurality of female electrode receptacles  450  that are disposed on the exterior surface of the main body plate  420 , as illustrated in  FIGS. 7 . The dedicated lighting device  415  further comprises at least one array of light emitting diodes (LEDs)  430 , a power sensor  442 , a motion sensor  440 , and a photo sensor  445  attached to the main body plate  420  as shown. These components are provided in electrical communication via corresponding electrical circuitry. 
   Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.