Abstract:
The present invention pertains to a night light assembly which plugs directly into an electrical wall receptacle to provide a beam of light that can be directed along different paths.

Description:
This application, which is the U.S. national stage of international application PCT/US2003/020633 designating the United States and filed Jul. 1, 2003, is a continuation-in-part of prior U.S. application Ser. No. 10/188,533 filed Jul. 2, 2002 (now U.S. Pat. No. 6,824,296 issued Nov. 30, 2004). 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to lights that are used to provide low level illumination in a room or passageway during the night, and more particularly to a night light assembly which provides a focused bean of light from an incandescent bulb or an LED that can be easily and selectively oriented from a rotatable assembly to shine in different directions and to an improved power supply circuit for an LED. 
   2. Description of the Related Art 
   Night lights which can be plugged into wall receptacles are normally used to provide low level illumination in a dark room or hallway. When used in a bedroom, a night light can provide sufficient light to allow a person, upon waking, to move about the room without banging into furniture, a doorway or such and still provide an ideal environment for sleeping. Where the bedroom is a child&#39;s nursery, a minimum amount of light in usually desirable. Very young children are often fearful of complete darkness and, in addition, should a parent wish to check on the sleeping child without turning on the room light, a low intensity night light that is continuously on is most useful and desirable. 
   The conventional night light consists of an electrical assembly having an electrical socket integrated with a plug for insertion into a wall receptacle. A low wattage lamp is held in the socket and a small translucent shade is usually provided to shield the lamp from direct view. A night light of this type normally uses a low wattage incandescent lamp which provide low level illumination. Light from the shielded bulb is normally reflected off an adjacent wall surface into the room to provide localized illumination that is purely utilitarian in function. The light is neither focused nor directionally controllable. 
   The patent to Victor, U.S. Pat. No. 6,200,001 illustrates a night light assembly which allows light from a small wattage lamp within the fixture to pass through a lens into the room. The beam of light emitted from the assembly can be directed by grasping and rotating a member containing a lens. 
   In the foregoing patent, the night light assembly has a stationary lamp which is positioned traverse to the rotational axis of the rotatable lens and, therefore, the filament of the lamp is not centered with the lens. With this arrangement, the base of the lamp interferers with and blocks reflected light from passing through the lens. In addition, the stationary lamp is hard wired to a PCB board that in turn is mechanically fastened to the prongs of the plug which not only increases the cost of manufacture of the assembly, but prevents the bulb from rotating with the head member. 
   A rotatable night light assembly that can direct a focused beam of light in different directions from a lamp aligned along the rotational axis of the lens to provide increased illumination, that is of a simple design and can be manufactured and sold at a relatively low cost is clearly desirable. 
   LED&#39;s are becoming more popular in residential and commercial lighting. Recently LED&#39;s have been used in night lights. As LED&#39;s operate at low DC voltage and low current, the power supply circuit for an LED typically uses resistor current limiting circuitry. The use of a resistor in the power supply circuit has the disadvantage of generating heat and not being the most efficient. What is needed is a power supply circuit for an LED that produces less heat and is more efficient. 
   SUMMARY OF THE INVENTION 
   In one embodiment, the present invention pertains to a night light assembly which plugs directly into an electrical wall receptacle to provide a beam of light that can be directed along different paths. The assembly comprises a housing having a plug with projecting blade contacts for insertion into a wall receptacle and a light sensor for automatically controlling the activation and de-activation of the lamp of the nightlight. A cover member rotatably supported by the housing includes a lens, a low wattage lamp, a support member, and a lamp retaining member. 
   The low wattage lamp in the cover assembly is coupled, via sliding contacts, to the blade contacts in the base housing. This arrangement allows the cover and the lamp to be rotated as a unit relative to the base housing without limitation. The lamp retaining member is non-rotatably coupled to the cover and is rotatably engaged by a retaining member fixed to the housing member. The longitudinal axis of the low wattage lamp located in the lamp retaining member is aligned along the rotational axis of the lens in the cover to permit both direct and reflected light to pass through the lens in the cover without being obstructed b the base of the lamp. The disclosed assemblage is a new improved nightlight of simple design which provides increased light and can be manufactured and sold at relatively low cost. 
   The low wattage lamp used in the nightlight can be either an incandescent bulb or a light emitting diode (LED) such as an ultrabright white LED either as a single bulb or a cluster of 2 or more bulbs. A photo sensitive circuit can be provided to automatically energize the incandescent bulb or the LED during low light conditions. When an LED is use as the light source, the LED is energized by a new improved power supply that is both simple in design and more efficient in operation than the standard power supply circuit used for LED&#39;s. 
   The foregoing has outlined, rather broadly, the preferred feature of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed concept and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention and that such other structures do not depart from the spirit and scope of the invention in its broadest form. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claim, and the accompanying drawings in which: 
       FIG. 1  is an exploded view of the embodiment of the invention; 
       FIG. 2  is a partial cut away perspective view of an embodiment of the invention illustrating the relationship of the various components relative to each other; 
       FIG. 3  is another partial cut away perspective view of the embodiment of the invention illustrating the relationship of the various components relative to each other; 
       FIG. 4  is a view of the top of a PCB having lamp contacts and a photo sensitive control circuit for controlling a low wattage incandescent bulb; 
       FIG. 5  is a schematic of a standard power supply circuit for an LED; 
       FIG. 6  is a schematic of a power supply circuit for an LED in accordance with the principles of the invention; 
       FIG. 7  is a schematic of another power supply circuit for an LED in accordance with the principles of the invention; 
       FIG. 8  is a schematic of a variation of the power supply circuit of  FIG. 7  for an LED in accordance with the principles of the invention; 
       FIG. 9  is a schematic of still another power supply circuit for an LED in accordance with the principles of the invention; 
       FIG. 10  is a schematic of a variation of the power supply circuit of  FIG. 9  for an LED in accordance with the principles of the invention; 
       FIG. 11  is a schematic of a further power supply circuit for an LED in accordance with the principles of the invention; and 
       FIG. 12  is a schematic of a power supply having a photo sensitive device for controlling a low wattage incandescent bulb for use in the night light. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , there is disclosed an exploded view of an embodiment of a night light in accordance with the principles of the invention, generally designated by numeral  10 . The assembly  10  is adapted to be plugged into a wall receptacle located in a bedroom, a nursery or any other room or passageway in which the use of a night light is needed to provide low level illumination for safety, convenience or for any other reason. The assembly includes a base member  12  and a cover member  38 . The base member consists of a first section  14  and a mating second section  16 . The base member  12  is made up of sections  14  and  16  each of which includes a rear wall  18  having two openings  20 ,  22  for receiving blade contact  24  and blade contact  26 . While the blades  24  and  25  are shown in  FIG. 1  as not being polarized, it is to be understood that in those instances where polarized blades are required by local code requirements, blade  24  can be the hot blade contact and blade  26 , which can be of slightly greater width, can be the neutral blade contact. A Printed Circuit Board (PCB) assembly  28  is mechanically connected to the rear ends of the blade contacts  24 ,  26  and the side edge of the PCB board is positioned against a step  29  on the inside surface of sections  14  and  16  of the base member  12  to lock the PCB  28  and the blades to the base member  12 . A neutral contact  32  for the lamp  78  is mechanically and electrically connected to the PCB board with three contacts  21 ,  23  and  25 ; and a neutral or side contact  32  for the lamp  78  is mechanically and electrically connected to the PCB assembly  28  with three contacts  27 ,  29  and  31  (see  FIG. 4 ). The hot contact  32  is provided to make mechanical and electrical contact with the center base contact of a low wattage lamp and neutral contact  30  makes mechanical and electrical contact with the side base contact of the low wattage lamp. The first section  14  of base member  12  supports an opening  34  sized to accept and retain a light sensor lens  36  below which is a light sensor ( not illustrated) electrically connected to the PCB assembly  28  to automatically control the flow of current to the low wattage lamp during low level light conditions. Referring to  FIG. 4 , there is shown a PCB with a photo cell connected to a standard circuit for energizing an incandescent bulb during low light conditions. As the circuit for controlling the lighting of the incandescent bulb and its mode of operation is known to those skilled in the art, neither the circuit configuration nor its operation will be described. The shape of bulb contacts  30 ,  32  shown are representative of a socket for receiving a bulb and can vary in design and configuration to accept a bulb having a candelabra base, a medium base, or a one or two piece holder for an LED etc. In operation, the light sensor or photo cell allows the lamp to be energized when the ambient light is below a predetermined level, and disconnects the lamp from the current source when the ambient light is above that level. 
   The cover member  38  consists of an internal support member  40  which provides support for a lamp support member  42  adapted to receive a low wattage lamp  78 , a lens retaining ring  46 , a cover  48  and a lens  50 . The cover member is a unitary assemblage which is rotatably coupled to base member  12 . 
   Referring to the cover member  38 , lens  50  supports projecting fingers  51  positioned around its periphery aligned to pass through the opening  54  located in a flange  52  of cover  48 . The flange  52  defines the same opening  54  located in cover member  38  for passing light. A lens retaining ring  46  has openings  53  located to receive the projecting fingers  51  of the lens  50  to hold the lens  50  securely against the flange  52  of the cover  48 . 
   Support member  40 , which can be light in color to function as a reflecting body for light from the low wattage lamp, has an outside diameter sized to fit within an annular recess located within the rear end of cover  48 . Support member  40  supports a centrally located opening  56  and opposing arm capturing and retaining recesses  58 ,  60  for capturing and holding the lamp support member  42 . Latch members  76  located at each end of each recess  58 ,  60  is provided to engage arms  62 ,  64  of the lamp support member  42  to hold lamp support member  42  captive to support member  40 , see  FIGS. 2 and 3 . 
   The lamp support member  42  has, at a first end, two outwardly projecting arms  62 ,  64  designed to be received by recesses  58 ,  60  and held within the recesses by latch members  76  located at the end of each recess. The other or second end  66  of lamp support member is flared outward and contains slots  43  to allow the flared end to flex inwardly. A centrally located opening  45  in lamp support member  42  defines a socket for receiving the low wattage lamp  78 . Lamp  78  can be inserted into the centrally located socket of the lamp support member  42  from the first end, and projecting pins of the lamp engage channels in the socket to lock the lamp in position in those instances where the lamp has a bayonet base. 
   During assembly, the projecting fingers  51  are passed through the opening  54  in cover  48  and extend through corresponding openings  53  of lens retaining ring  46  and is secured by, for example, ultrasonic welding, adhesive or the like, to lock the lens to the cover. 
   The flared end  66  of the lamp support member  42  is passed through the opening  56  in the support member  40  and held captive by outwardly projecting arms  62 ,  64  which are received by recesses  58 ,  60  and held in position by the latch members  76 . 
   A low wattage lamp  78  is now positioned within the socket in the lamp support member  42 . After the lamp support member  42  and the lamp  78  are inserted within and connected to the support member, the support member  40  is secured to the cover  48  by, for example, ultrasonic welding, adhesive or the like. 
   The printed circuit board  28  is connected to the rear ends of blades  24 ,  26  and supports electrical components thereon ( see  FIG. 4 ) required to enable a light sensor located behind light sensor lens  36  to control the on-off operation of the lamp  78  in response to ambient light. The ends of blade contact  24  and blade contact  26  project through the PCB and are electrically connected to the components on the board via electrical conducting trace paths on the board. As noted previously, the PCB shown in  FIG. 4  is of known design for supplying current to an incandescent bulb when the ambient light is below a predetermined level. The light sensor is positioned behind lens  36  which in turn is housed in opening  34  in the first section  14  of base member  12 . The sub-assemblies of the cover member  38  and the first  14  and second  16  sections of the base member  12  are now ready to be joined together to form the night light. 
   The PCB including blade contacts  24 ,  26  is placed into base member  16  with both blade contacts  24 ,  26  being located within slot openings  22  and  20  respectively. The flared second end  66  of the lamp support member  42  is positioned within cutout  70  of retaining wall  68  of the second section  16  of base member  12 . The cutout  70  of the second section  16  is located between the back face of support member  40  and the start of the flared section at the second end of the lamp support member  42 . The top section  14  is now positioned on top of the bottom section  16 , care being taken to insure that cutout  70  of retaining wall  68  of the top section is positioned between the back face of the support member  40  and the start of the flared section of the second end  66  of the lamp support member  42 . The two sections  14 ,  16  can be joined together by ultrasonic welding, an adhesive or the like. It is to be noted that by positioning the lamp support member  42  within the openings  70 ,  72  of the first and second sections of the base member  12 , the cover member  38  is rotatably coupled to base member  12  and the contacts of the lamp make electrical contact with the bulb contacts  30 ,  32 . Thus, cover member  38 , including the lamp, rotate together as a unitary unit, and can be rotated without limitation in either direction to allow a user to controllably direct a beam of light from a night light. 
   The bulb for the night light can be an incandescent bulb or an LED. LED&#39;s available today have certain advantages such as being light in weight, are available in different colors such as green, white, red, blue and amber, operate with low power levels, have a relatively long life and are available with various base contacts. LED&#39;s are finding use in residential and commercial applications. One recent use of LED&#39;s is in flashlights and night lights. As noted above, the bulb used in the night light described above can be either an incandescent lamp or an LED. In those instances where the bulb of the night light is an LED, there is here disclosed a new higher efficiency power supply of simple design which can be located on the PCB  28 . 
   The prior art power supply for an LED, which operate at low DC voltage and low current normally uses a resistor as the current limiting component. A disadvantage of using a resistor to limit the current is the generation of heat and loss of efficiency. The new improved LED power supply circuit here disclosed uses an energy storage component such as a capacitor or an inductor in combination with a resistor to provide power from the line to light the LED. With a resistor-capacitor (R-C) or resistor- inductor (R-L) network in series in the power line, the LED night light operates at a higher efficiency and generates less heat than the prior art LED power supply circuit which has only a resistor as a current limiting component. 
   Referring to  FIG. 5  there is shown a schematic circuit of a prior art power supply circuit  80  for an LED. Circuit  80  consists of a resistor  82 , a diode  84 , and an LED  86 , all in a series circuit arrangement. The purpose of the resistor is to limit the current in the circuit so that the LED  86  is not overloaded. The diode  84  blocks the AC current when its polarity is such that the LED is reversed biased. The diode is needed to block a high reverse voltage which cannot be done by the LED. Thus, the resistor  82  limits the forward biased current and the diode  84  blocks the reverse biased current. 
   Referring to  FIG. 6 , there is shown a schematic of a power supply circuit  130  for an LED in accordance with the principles of the invention. The circuit of  FIG. 6  is similar to circuit  80  with the addition of capacitor  83  in the series circuit. Thus, all the components of  FIG. 6  have the same reference numerals as the corresponding components of  FIG. 5  except for capacitor  83 . The capacitor  83  helps to limit the current to the LED. Because the capacitor has impedance that helps to limit the current in the circuit, the value of resistor  82  can be reduced without causing an increase in the circuit current. The reduction of the resistor value results in less power being dissipated in the resistor and, therefore, results in a circuit that is more efficient. 
   Referring to  FIG. 7 , there is shown a schematic of a power supply circuit  90  for an LED in accordance with the principles of the invention. Circuit  90  differs from circuit  80  in that it includes a parallel circuit of a diode  98  in parallel with the LED  96  and in reverse polarity with respect to the LED, and the parallel circuit is in series with a capacitor  92 . By adding the capacitor to the circuit, the value of the resistor can be decreased because the capacitor adds some impedance to the circuit. Thus, because the value of the resistor is reduced, less power is dissipated across the resistor and, therefore, the circuit is more efficient. Because the value of the resistor is reduced, the heat generated by the resistor is less. By placing the diode  98  in parallel with and in opposite polarity to that of the LED  96 , the current which flows through the LED is redirected through the diode when the AC signal reverse biases the LED. Thus, the diode is an alternate route for the current to travel as opposed to it being blocked. The circuit  90  of  FIG. 2  is adapted to be connected to a source of AC potential. 
   Referring to  FIG. 8 , there is shown a schematic of a power supply circuit  140  for an LED which is a variation of the power supply circuit of  FIG. 7 . All of the components of  FIG. 8  have the same reference numerals as the corresponding components of  FIG. 7  except for resistor  94  of  FIG. 7  which is relocated to be in series with LED  96  and is now identified as resistor  95  in  FIG. 8 . In the circuit of  FIG. 8 , the impedance of capacitor  92  and that of resistor  95  combine to limit the inrush of current. 
   Referring to  FIG. 9 , there is shown a schematic of another power supply circuit  100  for an LED in accordance with the principles of the invention. In the circuit of  FIG. 9 , a first input terminal of a bridge rectifier  116  is connected through a resistor  104  in series with a capacitor  102  to a first terminal adapted to be coupled to a source of AC voltage. The second input terminal of the bridge rectifier  116  is connected directly to a second terminal adapted to be coupled to the source of AC voltage. The bridge rectifier is comprised of diodes  106 ,  108 ,  110  and  112  connected in a bridge configuration having two input terminals and two output terminals. The two output terminals of the bridge rectifier  116  are connected across an LED  114 . In this circuit capacitor  102  is in series with resistor  104 . As with circuit  90  of  FIG. 7 , the benefits of a resistor having a reduced value because of the presence of the capacitor are reduced heat from the resistor, less loss by using a resistor of reduced value and, therefore, a higher operating efficiency. In addition, as the AC signal to the LED is fully rectified ( the negative half cycle is flipped to the positive side of zero voltage), the LED  114  is energized during the whole AC cycle. Thus, the current that is bypassed through the diode is used to light the LED. 
   Referring to  FIG. 10 , there is shown a schematic of a power supply circuit  150  for an LED which is a variation of the power supply circuit  100  of  FIG. 9 . All of the components of the circuit of  FIG. 10  have the same reference numerals as the corresponding components of  FIG. 9  except for resistor  104  of  FIG. 9  which is relocated to be in series with LED  114  and is now identified in  FIG. 10  as resistor  105 . Resistor  105  in combination with the capacitor limits the inrush of current to the LED. 
   Referring to  FIG. 11 , there is shown a schematic of still another power supply circuit  120  for an LED in accordance with the principles of the invention. In the circuit of  FIG. 11 , resistor  122 , diode  124 , LED  126  and capacitor  128  are all connected in series and adapted to be connected to a source of AC voltage. The resistor  122  and diode  124  block negative half waves. A second diode  130  is series with a second LED  132  are connected in parallel with the diode  124  and LED  126 , but in reverse polarity. With this circuit each LED  126 ,  132  is energized alternately by each half cycle of the AC wave. The capacitor  128  in series with the resistor  122  provides the same advantages noted previously where, because of the presence of the capacitor, the resistor has a reduced value which results in reduced heat from the resistor and higher operating efficiency. 
   In each power supply circuit shown, it is understood that an inductor can be substituted for the capacitor. 
   Referring to  FIG. 12  there is shown a power supply  200  having a photo sensitive device for an incandescent bulb for use in the night light disclosed. The input terminals  202 ,  204  of the power supply are connected to a source of power such as 120 V, 60 HZ. Input terminal  202  is connected through a diode  206  such as a IN4004 to an incandescent bulb  208  which can have a rating of 2 W at 60 V. A series circuit of a resistor  210  which can have a value of 2.4 M ohms and a photo sensitive device  212  such as a CDS are connected between the bulb and input terminal  204 . Thus, diode  206 , light bulb  208 , resistor  210  and CDS  212  are connected in series across the input terminals  202 ,  204 . A capacitor  214  having a value of 1 UF at 50V is connected in parallel with the CDS  212 . The anode terminal of a gated semiconductor device  216 , which can be an MCR100-6 is connected to the junction of the bulb  208  and resistor  210 , the gate terminal of device  216  is connected to the junction of the CDS  212  and capacitor  214 , and the cathode terminal of device  216  is connected to terminal  204 . 
   While there has been described herein the principles of the invention, it is to be clearly understood to those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention. Accordingly, it is intended, by the appended claims, to cover all modifications of the invention which fall within the true spirit and scope of the invention.