Abstract:
A nightlight including a light bank having light-emitting diodes (LEDs) disposed in an array. The amount of light emitted from the light bank can be varied by engaging a switch that selects between a number of electrical pathways. The device includes a photosensitive device such as a light dependent resistor or photo-diode for switching the device on or off under varying ambient light conditions. The photo-diode may be temporarily deactivated in bright ambient light conditions to check and change the settings of the LEDs.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     This invention generally relates to lighting devices. More particularly, the invention relates to an illuminating device which includes a LED (light-emitting diode) array. Specifically, the invention relates to a nightlight which includes a light bank having LEDs therein and which has multiple electrical pathways which can be selectively engaged to regulate the amount of light emitted from the light bank.  
         [0003]     2. Background Information  
         [0004]     Nightlights have been used for some time to provide sufficient light for a person to move around a room during the night without have to turn on an overhead light. A nightlight can provide comfort to young children who may be afraid of total darkness, can provide enough light for a parent to check on an infant or may provide light to negotiate the way to a bathroom without waking up an entire household.  
         [0005]     Originally, night lights were provided with a 7W incandescent light bulb. These night lights provided the necessary light to negotiate around a room, but because the bulbs were incandescent, they tended to generate some heat and tended to burn out fairly easily.  
         [0006]     In the last few years, LED (light-emitting diode) technology has advanced to the point that LEDs can be used for low-cost applications such as nightlights. The LEDs can emit various colors of light including white, green and red. The white LEDs tend to be high intensity LED devices which provide a fairly substantial amount of light. This is useful for locations such as bathrooms and staircases, but can be problematic if used in bedrooms because the quantity of light emitted can tend to interfere with some people falling asleep.  
         [0007]     There is therefore a need in the art for an illuminating device in which the quantity of light emitted by LEDs can be adjusted.  
         [0008]     There is further a need in the art for an illuminating device which can be checked and adjusted during daylight or bright ambient light conditions to determine and vary the settings of the LEDs so that they deliver a specified quantity of light in the dark.  
       SUMMARY OF THE INVENTION  
       [0009]     The illuminating device of the present invention is useful as a nightlight. The device includes a light bank having one or more LEDs (light-emitting diodes), a photosensitive device for switching the device on and off depending on the ambient light conditions surrounding the nightlight and an actuator button for selecting whether one, two or more of the LEDs are powered. The device&#39;s electrical circuit may includes a resistor to reduce the power delivered to one or more of the LEDs. The photosensitive device is positioned within or under the actuator button and is selectively coverable. This allows the user to determine how many of the bulbs are switched on or off and whether or not they are in a dimmed or undimmed condition, even when the nightlight is surrounded by a high level of ambient light. The nightlight can therefore put out a high level of light from one, two or more LEDs, or can put out a reduced level of light from one, two or more LEDs. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims.  
         [0011]      FIG. 1  is a front elevational view of a nightlight in accordance with the present invention;  
         [0012]      FIG. 2  is a side elevational view of the nightlight through line  2 - 2  of  FIG. 1 ;  
         [0013]      FIG. 3  is a front elevational view of the nightlight of  FIG. 1  when activated;  
         [0014]      FIG. 4  is a partial cross-sectional side view showing the actuating switch and photosensitive device disposed in the housing;  
         [0015]      FIG. 5  is a circuit diagram for a first embodiment of the nightlight;  
         [0016]      FIG. 6  is a schematic representation of the light bank LED array of  FIG. 5  showing the LED array with all three LEDs on and emitting maximum light;  FIG. 7  is a schematic representation of the LED array of  FIG. 5  showing the LED array with all three LEDs on and emitting dimmed light;  
         [0017]      FIG. 8  is a circuit diagram of a second embodiment nightlight;  
         [0018]      FIG. 9  is a schematic representation of the LED array of  FIG. 8  showing the LED array with one LED off and two LEDs on;  
         [0019]      FIG. 10  is a circuit diagram of a third embodiment of nightlight;  
         [0020]      FIG. 11  is a schematic representation of the LED array of  FIG. 10  showing only one of the LEDs in the on position; and  
         [0021]      FIG. 12  is a circuit diagram of a fourth embodiment of nightlight. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]      FIGS. 1-12  illustrates the preferred embodiments of a nightlight including a configuration and layout of a light bank including a LED array and electrical circuit relating thereto. It is, however, to be understood that modifications and variations may be made to the illustrated configuration and circuit layout without departing from the general principles of the invention hereinafter described.  
         [0023]     Referring to  FIGS. 1-3 , there is shown a nightlight in accordance with the present invention and generally indicated at  10 . Nightlight  10  comprises a housing  12  having a including a light bank  14  which includes one or more LEDs  16 ,  18  and  20 . LEDs  16 ,  18  and  20  preferably are medium intensity white LEDs, but if a single LED is used, it preferably is a very high intensity white bulb. LEDs  16 ,  18 ,  20  may be arranged in light bank  14  in any desired manner such as a row, circle or triangle. Nightlight  10  preferably is connected to alternating current and the housing  12  is therefore provided with electrical prongs  22  to connect device  10  to an electrical outlet (not shown).  
         [0024]     Referring to  FIG. 4 , LEDs  16 ,  18 ,  20  are connected to a switch  26  which is activated by depressing a button  24  on housing  12 . Switch  26  may be connected to a resistor (not shown in this figure) to reduce current to LEDs  16 , 18  and  20 . Alternatively switch  26  may be connected into the circuit in such a manner as to selectively switch one or two of the LEDs into or out of the circuit so that the light emitted from device  10  is dimmed or brightened by the number of bulbs illuminated.  
         [0025]     Nightlight  10  is switched on or off by way of a photosensitive device  28  disposed at one of within or behind button  24 . Button  24  is made from a transparent material which allows light from the environment surround device  10  to be received by the photosensitive device  28 . In bright ambient light, the photosensitive device  28  substantially prevents current from flowing through LEDs  16 , 18  and  20  and thereby turns LEDs  16 , 18  and  20  off. In low ambient light conditions the photosensitive device  28  allows current to flow through LEDs  16 ,  18 , and  20  and thereby turns the LEDs on. Button  24  preferably is recessed in housing ( FIG. 2 ) so that light emitted from LEDs  16 ,  18 ,  20  does not deactivate the photosensitive device  28  which would in turn switch LEDs  16 , 18  and  20  off. It will be understood by those skilled in the art that any suitable photosensitive device  28  may be utilized in circuit  30  to switch LEDs  16 ,  18 ,  20  on or off. Such photosensitive devices include light dependent resistors (LDR&#39;s) and photo-diodes. The remainder of this specification will make reference to photo-diodes, but it is to be understood that the description applies equally to LDR&#39;s or other photosensitive devices.  
         [0026]     Referring to  FIGS. 5-7 , there is shown an electrical circuit  30  for a first embodiment of nightlight  10  in accordance with the present invention. Circuit  30  includes three LEDs  16 ,  18 ,  20  connected in series with an AC source (not shown) via prongs  22 . It will be understood that circuit  30  could, however, include only one LED or could include more than three LEDs without departing from the spirit of the present invention. Circuit  30  includes a photo-diode circuit, well known in the art and identified by box  32 . Circuit  30  further includes capacitors  34 ,  36 , a rectifier  38  to change alternating current from the power source to direct current, and resistors  40  and  42 . Switch  26  is provided to selectively route current through a resistor  44 . When switch  26  is open, current does not flow through resistor  44  and consequently the maximum amount of current flows through LEDs  16 ,  18 ,  20  and the maximum possible amount of light is emitted by LEDs  16 ,  18  and  20 . This situation is illustrated in  FIG. 6 , where the amount of light emitted from light bank  14  is shown by long lines radiating outwardly from LEDs  16 ,  18  and  20 . When switch  26  is closed, current flows through resistor  44  reducing the voltage received by all three LEDs  16 ,  18 ,  20 , resulting in less light being emitted by device  10 . This situation is illustrated by  FIG. 7 , where the amount of light emitted from light bank  14  is shown by short lines radiating outwardly from LEDs  16 ,  18  and  20 . Should brighter light be required from device  10 , switch  26  can be opened again to prevent current from flowing through resistor  44 .  
         [0027]     Referring to  FIGS. 8-9  there is shown an electrical circuit for a second embodiment of nightlight in accordance with the present invention and referenced by the number  130 . In circuit  130 , LEDs  116 ,  118  and  120  are connected in series with an AC power source (not shown) via prongs  122 ; and to a well-known photo-diode circuit represented by box  132 . Circuit  130  includes two capacitors  134  and  136 ; a rectifier  138  and biasing resistors  140 ,  142  and  144 . Switch  126  is connected into circuit  130  so that when switch  126  is activated, current can be routed through either all three LEDs  116 ,  118  and  120  or one of the LEDs, namely  120 , can be cut out of circuit  130 . When switch  126  is in a first position, current flows through the pathway represented by “A”( FIG. 8 ) and all three LEDs  116 ,  118  and  120  are on. When switch  126  is in a second position, current flows through the pathway represented by “B” and through resistor  144 . In this second instance, only LEDs  116  and  118  are illuminated. As a consequence, the light emitted by nightlight  10  is dimmer than when all three LEDs  116 ,  118 ,  120  are emitting light. The nightlight is therefore effectively dimmed. This second situation is illustrated by the array  114  shown in  FIG. 9  where only LEDs  116  and  118  are shown emitting light. If the user wishes to increase the amount of illumination from device  10 , switch  126  is depressed again to reroute current through all three LEDs  116 ,  118  and  120 .  
         [0028]     Referring to  FIGS. 10-11  there is shown an electrical circuit for a third embodiment of nightlight in accordance with the present invention and referenced by the number  230 . In circuit  230 , LEDs  216 ,  218  and  220  are connected in series with an AC power source (not shown) via prongs  222 ; and to a well-known photo-diode circuit represented by box  232 . Circuit  230  includes two capacitors  234  and  236 ; a rectifier  238  and biasing resistors  240 ,  242  and  244 . A two-way switch  226  is provided to selectively route current through all three LEDs  216 ,  218  and  220 ; or through only one of the LEDs, namely bulb  216 . When switch  226  is in a first position, current flows through the pathway represented by “C” ( FIG. 10 ) and all three LEDs  216 ,  218  and  220  are illuminated. When switch  226  is in a second position, current flows through the pathway represented by “D” and through resistor  244 . In this second instance, only LED  216  is illuminated. As a consequence, the light emitted by nightlight is substantially dimmer than when all three LEDs  216 ,  218 ,  220  are emitting light. The nightlight is therefore effectively dimmed. This second position of switch  226  is illustrated by the array  214  shown in  FIG. 11  where only LED  216  is shown emitting light. Should the user wish to have the device  10  emit more light, switch  226  is depressed so that current flows once again down pathway “C” and through all three LEDs  216 ,  218  and  220 .  
         [0029]     Referring to  FIG. 12  there is shown an electrical circuit for a fourth embodiment of nightlight in accordance with the present invention and referenced by the number  330 . Circuit  330  includes all components shown in either of the second and third embodiments of nightlight, but the switch  326  is a three-way switch and circuit  330  includes two biasing resistors  344  and  346 . Switch  326  allows for pathways “F”, “G” or “H” to be selected. When pathway “F” is selected, all three LEDs  316 ,  318  and  320  are on. When pathway “G” is selected, only LEDs  316  and  318  are on. When pathway “H” is selected, only LED  316  is on. It is therefore possible for a user to select a graduated dimming or brightening of the nightlight depending on how much light they wish the device to emit.  
         [0030]     It will be understood by those skilled in the art that a switch and associated resistor may be incorporated into any of the second, third or fourth embodiments of the present invention without departing from the scope of the present invention.  
         [0031]     With reference to the first embodiment of the invention, nightlight  10  is used in the following manner. Device  10  is plugged into an AC power outlet by way of electrical prongs  22 . Photo-diode  28  senses the ambient light conditions surrounding device  10  by receiving light through button  24 . If the ambient light conditions are bright, circuit  30  is broken and none of the LEDs  16 , 18  and  20  light up. If photo-diode  28  senses low ambient light conditions surrounding device  10 , photo-diode  28  closes the circuit  30  and all three LEDs  16 , 18  and  20  light up. If the user wishes to dim device  10 , they engage switch  26 . This causes current to flow through resistor  44  and all three LEDs  16 , 18  and  20  are dimmed. If the user wishes more light to be emitted from device  10 , they depress button  24  again so that switch  26  opens and current no longer flows through resistor  44 . All three LEDs  16 ,  18  and  20  therefore emit the maximum possible amount of light. Because photo-diode  28  is positioned inside clear button  24 , if the user places their finger over button  24 , photo-diode  28  automatically senses low ambient light conditions and LEDs  16 , 18  and  20  light up. The user can then see, even in bright ambient light conditions, whether LEDs  16 , 18 , and  20  are in a dimmed or undimmed condition.  
         [0032]     In the second, third and fourth embodiments, the activation switch  126 ,  226  or  236  respectively, can be used to select how many LEDs are included in the circuit and therefore how bright or dim the light emitted from the device is. This selection is made by depressing the button  24  on the housing  12  until the appropriate number of LEDs are illuminated. As with the first embodiment of the invention, the number of bulbs illuminated can be checked even in bright ambient light conditions by the user simply placing their finger over the button  24  to substantially prevent any light from reaching the photo-diode  128 ,  228  and  328 , respectively. When the photo-diode is covered, the circuit is closed and the activated LEDs included in the circuit light up. The user can change the amount of light emitted by the nightlight by depress the button  24  until the desired number of LEDs are emitting light. When the user removes their fingertip from button  24 , the photo-diode switches the nightlight off. In low ambient light conditions, the activated LEDs can be easily observed. The number of activated LEDs can be changed by depressing button  24  until the desired number are lighted. In this manner, the user can select the brightness or dimness of the nightlight in both bright and low ambient light conditions.  
         [0033]     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.  
         [0034]     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.