Patent Abstract:
A night light design which allows for improved functionality over those heretofore available. The basic design is flexible enough to be adapted for either indoor or outdoor use, and for various brightness levels. Particularly for outdoor use, bulbs of up to 15 watts can be used, providing an increased illumination level. All designs preferably include a light sensing element and a control circuit, wherein the light turns itself on when the ambient lighting levels fall low enough. Also, several preferred embodiments include a variable control, wherein the brightness of the night light can be continuously varied between very dim and full brightness.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation, of application Ser. No. 09/222,901, filed 30 Dec. 1998, entitled “Night Light now U.S. Pat. No. 6,390,647.” 
     This application claims priority from U.S. Provisional application No. 60/070,248, filed Dec. 31, 1997, which is hereby incorporated by reference hereinto in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to lighting devices, and more particularly to night lights having adjustable controls. 
     2. Description of the Prior Art 
     It is common to provide one or more night lights in various rooms of the home. The lights are plugged in to any convenient outlet, and provide a relatively small amount of light suitable for finding one&#39;s way when other light sources are off. This is very useful for providing enough light to move around the house, without being so bright as to interfere with sleeping. 
     Until now, night lights generally available have a fixed brightness, and must be switched on and off by hand. Some designs have proposed various more complicated controls, but have not met the requirements and desires of those needing more flexibility in a night light. 
     Also, night lights have previously been limited to indoor use. In certain instances, it would be desirable to provide a night light which could be used outdoors to provide limited lighting without the necessity for installing a complex permanent fixture. An outdoor night light could be used temporarily for any of a wide variety of purposes, or could be left in place to illuminate, for example, a door to aid in night entry into the home. 
     Whether for indoor or outdoor use, it would be desirable to provide a night light fixture which is inexpensive, while providing lighting levels and control functions beyond those available on current products. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a night light design is provided which allows for improved functionality over those heretofore available. The basic design is flexible enough to be adapted for either indoor or outdoor use, and for various brightness levels. Particularly for outdoor use, bulbs of up to 15 watts can be used, providing an increased illumination level. All designs preferably include a light sensing element and a control circuit, wherein the light turns itself on when the ambient lighting levels fall low enough. Also, several preferred embodiments include a variable control, wherein the brightness of the night light can be continuously varied between very dim and full brightness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, as well as preferred modes of use, further objectives and advantages thereof, will best be understood by reference to the following detailed descriptions of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  illustrates a night light according to the present invention; 
         FIG. 2  illustrates a second embodiment of a night light according to the present invention; 
         FIG. 3  depicts a third embodiment of a night light according to the present invention; 
         FIG. 4  depicts a fourth embodiment of a night light according to the present invention; 
         FIG. 5A  shows another embodiment of a night light according to the present invention; 
         FIG. 5B  illustrates a side view of the night light shown in  FIG. 5A ; 
         FIG. 5C  illustrates a preferred cover plate design for the night light shown in  FIG. 5A ; 
         FIG. 6A  depicts yet another embodiment of a night light according to the present invention; 
         FIG. 6B  is a front view of the night light shown in  FIG. 6A ; 
         FIG. 7  is a schematic diagram of a preferred control circuit for use with various night light designs; 
         FIG. 8A  is a side view illustrating an alternative embodiment of the night light shown in  FIG. 6A ; 
         FIG. 8B  is a front view of the embodiment shown in  FIG. 8A ; 
         FIG. 9  is an alternative control circuit for use with various night light designs; 
         FIG. 10A  depicts an outdoor embodiment of a night light according to the present invention; 
         FIG. 10B  is a front view of the night light shown in  FIG. 10A ; 
         FIG. 11A  illustrates construction details of the embodiment shown in  FIG. 5A ; 
         FIG. 11B  shows additional details of the embodiment shown in  FIG. 5A ; 
         FIG. 12A  is a perspective view of a final illustrative preferred embodiment of the invention; 
         FIG. 12B  is a top view of the embodiment shown in  FIG. 12A ; 
         FIG. 12C  is a side view of the embodiment shown in  FIG. 12A ; and 
         FIG. 12D  is a top and partially broken away view of the embodiment shown in  FIG. 12A . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Several features of the invention are described below in various embodiments and combinations. It will be appreciated by those skilled in the art that various additional combinations of features may be implemented while utilizing the teachings of the present invention. 
       FIG. 1  illustrates night light  100  according to the present invention. Forming the central portion of night light  100  is base  112 . Base  112  provides the central support structure for night light  100 , and contains the majority of the electrical components of night light  100 . Located on the back portion of base  112  is either a two or three prong plug which is designed to be received in any common electrical outlet. 
     On the front portion of base  112  is dimming knob  108 . Dimming knob  108  is connected to a dimming switch internal to base  112 . This dimming switch controls the brightness of light bulb  104 , and can switch light bulb  104  on or off. In one embodiment of the present invention, the dimming switch is a rheostat type device, but, the dimming switch could also be a solid-state, semiconductor device. The dimming switch can be in one of three states: the off state, the dimming state, and the on state. The dimming switch can be put into the off state by turning dimming knob  108  fully clockwise. When a user turns dimming knob  108  from the dimming state to the off state, and vice versa, they will feel dimming knob  108  “click.” While the dimming switch is in the off state, light bulb  104  will never switch on. 
     In a similar manner, the dimming switch can be switched to the on state by turning dimming knob  108  fully counterclockwise. The user will feel dimming knob  108  click when it is turned from the dimming state to the on state, and vice versa. When the dimming switch is in the on state, light bulb  104  will shine continuously. 
     The dimming switch is put into the dimming state by turning dimming knob  108  slightly counterclockwise from the off state, or slightly clockwise from the on state. When light bulb  104  is switched on by sensors  110  (as will be described below) and the dimming switch is in the dimming state, the dimming switch will control the brightness of light bulb  104 . To make light bulb  104  appear dim, dimming knob  108  is turned to the far clockwise position of the dimming state. To make light bulb  104  appear bright, dimming knob  108  is turned to the far counterclockwise position of the dimming state. 
     When the dimming switch is in the dimming state, light bulb  104  will be switched on by sensors  110 . Sensors  110  are comprised of either an ambient light sensor, a motion sensor, or both. If night light  100  contains an ambient light sensor, light bulb  104  will be switched on when the ambient light around night light  100  decreases to a predetermined level. Generally, this level will be at the point where persons begin to find it difficult to make out objects around them. If night light  100  contains a motion sensor, light bulb  104  will be switched on when the motion sensor detects movement in the vicinity of night light  100 . If night light  100  includes both a motion and an ambient light sensor, light bulb  104  will be switched on during low light levels by the ambient light sensor and will be switched on by the motion sensor at other times when motion is detected around night light  100 . If light bulb  104  is tarried on by the motion sensor, the light will stay on for a predetermined period of time and then will switch off. Either the motion sensor or the ambient light sensor, or both, can have a variable control (not shown) to set the sensitivity to a desired level. In the preferred embodiment, sensors  110  control light bulb  104  only when the dimming switch is in the dimming state. If the dimming switch is in the off state, sensors  110  will have no effect on light bulb  104 . Likewise, if the dimming switch is in the on state, sensors  110  will again have no effect on light bulb  104 . 
     Covering light bulb  104  is textured cover plate  102 . Textured cover plate  102  can be constructed of many materials, including both plastic and glass. Textured cover plate  102  both protects light bulb  104  from being broken and prevents objects from inadvertently coming in contact with the hot bulb. Textured cover plate  102  can also diffuse the light of light bulb  104 , resulting in a “softer” light emanating from night light  100 . In one embodiment of the present invention, light bulb  104  is a 15 Watt bulb. 
     Night light  100  can be designed to be used both indoors and outdoors. In order to be suitable for use outdoors, water and dirt must be prevented from entering base  112 , where they could damage or otherwise render inoperable the electronics. Seal  106  is used to prevent water from entering where the light socket and base  112  join. Likewise, there are other seals behind dimming knob  108 . The slits in base  112 , which allow sensors  110  to monitor the outside world, have been designed to keep the intrusion of water and dirt into base  112  to a minimum. These weatherproofing design features allow night light  100  to be used outdoors, where many other night lights cannot. 
       FIG. 2  illustrates a second embodiment of a night light according to the present invention. Night light  200  is similar to night light  100 , with some differences which will be described below. Night light  200  contains 2, 7 to 7½ Watt light bulbs, light bulb  204  and light bulb  205 . Whether a single light bulb or both light bulbs are illuminated when the dimming switch is in any particular state depends upon the setting of high-low switch  214 . When high-low switch  214  is in the low position, only light bulb  204  can be illuminated. As with night light  100 , the illumination of light bulb  204  will depend upon the state of the dimming switch. When high-low switch  214  is in the high position, both light bulb  204  and light bulb  205  can be illuminated, depending upon the setting of the dimming switch. 
     Whereas the dimming switch in night light  100  was controlled by dimming knob  108  on the front portion of base  112 , the dimming switch of night light  200  is contained within base  212 . The dimming switch used with night light  200  is rotated by turning cover plate  202 . This type of operation eliminates the opening in base  212  created by connecting the dimming knob to the dimming switch. This feature makes night light  200  more resistant to the effects of water and dirt. 
       FIG. 3  illustrates a third embodiment of a night light according to the present invention. Night light  300  is similar to night light  100 , shown in  FIG. 1 , with the exception that sensor  310  is mounted flush with base  312 . As noted above, night light  100  contains slits in its base to allow sensors  110  to view the external surroundings. In night light  300 , sensor  310  is mounted flush with and is sealed against base  312 . This provides additional protection from the intrusion of water and dirt into the inner portions of base  312 . As shown in  FIG. 3 , sensor  310  is either an ambient light sensor or a motion sensor. 
       FIG. 4  illustrates a fourth embodiment of a night light according to the present invention. Night light  400  is similar to the one shown and described in  FIG. 1 , with the exception of sliding dimmer switch  408  and sensor  410 . Sensor  410  is similar to the sensor contained within night light  300 , shown in  FIG. 3 . Sliding dimmer switch  408  is used in place of dimmer knob  108  and the associated dimming switch. Like the dimming switch used in night light  100 , sliding dimmer switch  408  can be in one of three states. However, instead of rotating about a central axis, sliding dimmer switch  408  moves vertically with respect to base  412 . When sliding dimmer switch  408  is depressed fully downward, night light  400  will be put into the off state and will be turned off. In a similar manner, when sliding dimmer switch  408  is positioned to the top of its range of travel, night light  400  will be in the on state. When sliding dimmer switch  408  is somewhere between the on state and off state, it will be in the dimming state and will function like the dimming switch in night light  100 . 
       FIG. 5A  shows another embodiment of a night light according to the present invention. Instead of having a cover plate located above a base portion, cover plate  506  of night light  500  is located in front of and completely surrounds base  501 . Thus, when night light  500  is plugged into a socket, all that is visible is cover plate  506 . 
     Although the arrangement of base  501  and cover plate  506  is different than the corresponding arrangement of night light  100 , night light  500  functions in a manner similar to that of night light  100 . The activation of light bulb  502  is controlled by rotating cover plate  506  as described in the discussion of night light  200 . Also controlling the activation of light bulb  502  are sensors  504 .  FIG. 5B  illustrates a side view of night light  500 .  FIG. 5B  shows the location of electrical plug  508 . Because the cover plate  506  is rotatably attached to the base  501 , no separate control is needed. This is similar to the dimming function of the embodiment described in  FIG. 2 . The design of  FIG. 5  provides minimal size combined with enhanced aesthetics, while still allowing a dimmer function to be incorporated.  FIG. 5C  illustrates a preferred cover plate design which is pleasing to view as well as functional. 
     The specific examples set forth above have illustrated several combinations of features, and it will be appreciated by those skilled in the art that other combinations of these and similar features can be used. For example, given the teachings contained in the above descriptions, it will be apparent that any design can incorporate a cover plate which is rotatable with respect to the base. This would allow any night light design to provide the dimmer function without the addition of an extra dimmer control. In a similar manner, ambient light and motion sensors may be included or deleted from any particular design as desired. The embodiment shown in  FIG. 1  describes one possible control function relating to setting the dimmer control to the ambient light or motion sensors, but it will be apparent to those skilled in the art that different control functions are possible. For example, a fully “on” position, which bypasses the sensor control functions could be eliminated. As another example, the motion sensor could be set to always turn the night light on to its full brightness, while the ambient light sensor would energize the night light at the lighting level set by the dimmer switch. Many other combinations of features can be utilized. 
     One preferred feature of the invention is that at least some models of the night light be suitable for outdoor use. Because this requires sealing the unit against dirt and weather, designs intended for outdoor use may be simpler than those intended for indoor use. For example, an outdoor light of the style shown in  FIG. 5B  could be provided with a simple on-off switch rather than a dimmer, and possibly combined with an ambient light sensor. With the device turned on, the night light would always on. When the switch is set in the off position, the ambient light sensor would turn the light on when the ambient light levels dropped below a preselected level. A third, completely off, switch position could be provided if desired. Other variations will become apparent to those skilled in the art. Several embodiments intended for outdoor use are described below in more detail. 
     Another useful feature of the embodiments described above is that at least some models provide for greater light output than is typically provided in night lights heretofore available. Incorporation of a bulb in the 15-20 watt range would provide a fairly high illumination level which is particularly useful outdoors. Because 7 watt bulbs are already generally available, some designs may include two or more bulbs in a single housing to obtain the desired illumination. 
     Some additional night light units will now be described. In large part, these units include various of the features set forth above. In some cases, additional features will be described, and those skilled in the art will understand the following descriptions insofar as they relate to the previous descriptions and features. 
       FIG. 6A  is a side view of yet another night light according to the present invention.  FIG. 6B  is a front view of the same night light unit. The unit includes a housing  602  having a socket  604  for a bulb  606 . Blades  608  project from the rear of the unit to connect it to a wall receptacle. A dimmer control  610  projects from the front of the housing  602 . As seen in  FIG. 6B , a photocell  614  is mounted immediately below the dimmer control  610 , and is used to turn the light on in low ambient light conditions as previously described. Cover plate  612  covers the bulb  606 , and is clear, frosted, or textured as desired to provide the appropriate light levels when the bulb  606  is on. 
     In order to prevent overheating of the unit, vents (not shown) are preferably provided in the top of the cover plate  612 . Vents may also be provided in the sides of the cover plate  612  near the bottom to provide improved airflow over the bulb  606 . This allows heated air to rise from the bulb  606 , keeping it significantly cooler than would be the case with no venting. Keeping the bulb  606  and cover plate  612  cooler contributes both to safety and to enhanced bulb life. 
       FIG. 7  depicts a preferred control circuit for use with the embodiment of  FIG. 6 . This same control circuit is suitable for use with the previously described embodiments, and with most of the following embodiments as will be described below. Control circuit  702  for a night light bulb  704  includes a triac  706  (or other solid state switch) as the primary control, in a manner well known to those skilled in the art. Resistors  708 ,  710  control current into the gate of the triac  706 , with resistor  710  being variable to control the brightness setting of the night light. 
     Photocell  712  is used to vary the current into the control gate of triac  706 , thereby controlling the brightness of bulb  704 . The resistance of photocell  712  varies with the ambient light, decreasing with decreasing ambient light levels, and thus increasing the control gate current. Increasing the control gate current increases current flow through bulb  704  as is known in the art. Bypass resistor  716  functions to limit current flow through the photocell  712 . For use with a 110 volt supply and a bulb  704  of 7-15 watts, the following component values can be used: resistor  716  has a resistance of 47K ohms, resistor 710 can be varied from 0-22K ohms, and resistor  708  has a value of 30K ohms. The photocell can be any of a large number of generic photocells, such as the EG&amp;G Optoelectronics Night Light Control (models VT800 or VT900). The triac can be any suitable device, such as the Piher 300K device, reference #  217 . As will be appreciated by those skilled in the art, variations on the described control circuit, suitable for use with particular devices, will be suitable for use with the night light. 
       FIGS. 8A and 8B  illustrate a variation on the embodiment of  FIG. 6 . This embodiment is suitable for use outdoors. It includes a gasket  802  on the rear of the housing  804  to seal the housing  804  to be weathertight. Cover plate  806  is also sealed to be weathertight. Alternatively, cover plate  806  can include vents as in the embodiment of  FIG. 6 , and a gasket (not shown) around the base of the bulb  808  to seal the electronics from the weather. 
     As can be seen in  FIG. 8B , the outdoor light preferably has only a photocell sensor  810  to turn the light on when ambient light drops. Normally, outdoors an on/off switch is not important, as the light is always wanted on when it is dark. The photocell  810  can be located behind a clear portion of the housing  804 . Deleting the knob for the controller eliminates the difficulty of sealing around the shaft of the variable resistor, and lowers cost for the unit at the same time. The control circuit of  FIG. 7  can be used for this night light, with the variable resistor  710  shorted out. 
     An alternative circuit for use primarily with outdoor night lights is illustrated in  FIG. 9 . This circuit is turned on and off as a function of ambient light levels, and does not include a dimmer function. In the circuit of  FIG. 9 , bulb  902  is turned on and off by triac  904 . Photocell  906  is connected to the control gate of the triac  904 , and turns the triac on when ambient light levels drop low enough. Capacitor  908  assists operation of photocell  906  as known in the art, and resistor  910  performs a current-limiting function in case the  902  burns out. 
     The control circuit in  FIG. 9  is suitable for use with the outdoor night light of  FIGS. 8A and 8B , but is less desirable for use with indoor lights because the dimming feature is not provided. 
     Outdoor night lights are also preferably provided with a ground-fault circuit interrupter (GFCI), which is connected to either the control circuit of  FIG. 7  or the control circuit of  FIG. 9  as known in the art. In order for a GFCI to work, of course, the night light must be provided with a three-terminal grounded plug such as shown in  FIG. 8A . One GFCI device which is suitable for use in night lights of the present type is the LM1851N manufactured by National Semiconductor. Other GFCI units are available, and may be included in either control circuit as is known in the art. 
       FIGS. 10A and 10B  depict another embodiment of the night light of the present invention which is intended for outdoor use. It is similar to the embodiment of  FIGS. 8A and 8B , except that it is designed for use with a 15 watt bulb, rather than the standard 7 watt bulb as is the case with  FIGS. 8A and 8B . 
     Because the 15 watt bulb  1002  is larger and hotter, the cover plate  1004  is larger. As before, cover plate  1004  may include vents, with a gasket (not shown) around the base of the bulb  1002 . Or, it may be unvented, with the cover plate  1004  completely weather sealed, such as by a gasket or O-ring  1010  around its base. Housing  1006  is extended rearwardly because of the larger cover plate  1004 . A gasket  1008  is used to seal the rear portion of the housing  1006  adjacent to the blades  1012 , which are of the three prong grounded type as described with respect to  FIG. 8A . As before, the ground fault interrupter circuit is preferably added to the control circuit, as described with reference to  FIGS. 7 and 9 . 
     As before, this design preferably has no dimmer switch, but uses a photocell  1014  to turn the unit on when ambient light levels drop. A separate on/off switch may be provided, but is not shown in  FIG. 10B . Because the unit can simply be unplugged to turn it off, such a switch is generally not necessary or desired. 
       FIGS. 11A and 11B  illustrate additional details of the night light unit previously described with respect to  FIGS. 5A ,  5 B and  5 C.  FIG. 11A  shows the base portion of the night light with the cover plate  506  removed. 
     Referring to  FIG. 11A , a side view of the night light shows a dimmer knob  1102  projecting from the housing  1104 . This knob has teeth, or grooves, to engage corresponding teeth or grooves with the arcuate slot  1106  shown in  FIG. 11B. 11B  is a view from the rear of the cover plate, showing the supporting ring structure and a projecting region  1108  which contains the arcuate slot  1106 . As the cover plate is rotated, the ring  1110 , and thus the projecting region  1108 , rotate with it. The engagement of teeth between the arcuate slot  1106  and the dimmer knob  1102  causes the dimmer knob  1102  to rotate, varying the resistance of the control circuit as shown in  FIG. 7  and brightening and dimming the output of the night light. Other mechanical constructions for adjusting the value of a resistor by turning the cover plate  506  will become apparent to those skilled in the art. 
     A variation of an outdoor night light which can be more permanently mounted is shown in  FIGS. 12A ,  12 B,  12 C, and  12 D. An alternative design for an outdoor night light which is simple and useful, but not so easily removable as the plug-in version previously described, is shown. In general, a night light of this embodiment is incorporated into a cover plate for a standard two-outlet electrical receptacle which is substituted in place of the normal cover plate used for outdoor receptacles. 
       FIG. 12A  is a perspective view showing the night light unit/outlet box covering of the present invention. When the standard, existing outlet box cover is removed, normally by the removal of single, central screw, the cover of  FIG. 12A  is inserted in its place. The cover includes a cover portion  1202  similar to a standard outlet box cover. The unit includes a hinged door  1204  which is connected to the cover portion in the usual manner and covers an opening  1206  in precisely the same manner as standard outdoor outlet box covers. In other words, the right-hand portion of the unit as shown in  FIG. 12A  is a standard replacement for the outlet box cover already normally installed. 
     The left-hand portion of the unit, as shown in  FIG. 12A , is covered by a cover plate  1208 , which is made out of any suitable transparent material and functions as does the cover plate on any of the previously-described night lights. The cover plate  1208  is large enough to completely cover up one side of the cover portion  1202 . 
     This can be seen more clearly in  FIG. 12B , which is a top view of the unit, as installed, with the hinged door  1204  in the closed position. Screw hole  1210  is provided for attaching the cover portion  1202  to the underlying receptacle in the outlet box. 
     Referring to  FIG. 12C , the lighting unit is seen to have a standard three-prong blade set  1212  extending from beneath the cover plate  1208 . Blades  1212  are aligned to plug into one side of the underlying outlet, leaving the other side free to be exposed through the opening  1206 . Beneath the cover plate  1208 , and disposed on the cover portion  1202 , is a housing  1214  which contains the control circuitry for the night light. Bulb  1216  is screwed into socket  1218 , both of which are contained within the cover plate  1208  in much the manner of any other outdoor night light as previously described. 
       FIG. 12D  is another top view of the unit, with the cover plate  1208  removed, and the hinged door  1204  in the closed position. Shown in phantom are the underlying receptacles within the outlet box. As can be seen from viewing  FIGS. 12C and 12D  together, the blades  1212  plug directly into the underlying receptacle. This allows the unit to be designed as simply a replacement outlet box cover, with no rewiring of any type needed. 
     The replacement outlet box cover is provided with necessary gaskets to seal both the cover plate  1208 , and the cover portion  1202  against the underlying surface so that the outlet box is also sealed. These sealing techniques are similar to those in wide use on outlet box cover plates. This design allows the night light to be replaced by any homeowner in less than two minutes with a single screwdriver, and requires no rewiring whatsoever. The resulting outlet, instead of having two receptacles, now has a single, weatherproof receptacle and an attached night light. This night light is preferably the type which uses a photocell control, without the dimmer function, as described in connection with  FIG. 9 . 
     As will be appreciated by those skilled in the art, the above described preferred embodiments illustrate several features of the present invention. A night light with a variable dimmer is flexible in use, allowing a relatively bright bulb to be controlled to a dimmer light output. If full light output is needed it is available; if less light is needed, that is easily obtained by controlling the dimmer. This easy control means that the user does not have to provide separate lights or replacement bulbs, which is inconvenient. 
     Also, several designs suitable for use as outdoor night lights have been illustrated. Standard night lights are not used outdoors because of their lack of protection against the elements. Proper sealing as described allows the benefits of a night light to be obtained out of doors. Because some of the designs are removable, the night lights may be placed and used as desired. If a relatively permanent light is desired, the alternative of  FIG. 12  can be installed by any homeowner in just a minute or 2 using no special tools. This type of installation provides a light source at an existing outlet, which is often located near a door. These locations are the ones most likely to be needed, to assist in finding of keys, etc., to enter the house at night. Additional benefits, such as being able to identify visitors at night, discouraging prowlers, and being able to view unfavorable weather conditions such as icy sidewalks, are also obtained. The relatively permanent installation prevents pilferage, while leaving one receptacle available for other use. 
     While the invention has been particularly shown and described with references to several preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Technology Classification (CPC): 8