Abstract:
A light fixture is disclosed which combines one or more electroluminescent light sources with a light emitting bulb. The unit may function as a night light, and partake of various different configurations, including a table lamp or desk set.

Description:
FIELD OF INVENTION 
     The present invention relates to a light fixture which includes one or more electroluminescent light sources in the conductive path to the light emitting bulb. The electroluminescent light source may be selectively energized independent of, or in conjunction with, the light emitting bulb to provide a practical and aesthetically desirable night light. 
     BACKGROUND OF THE INVENTION 
     A variety of light fixtures are known which include a manually operable switch in conjunction with a light emitting bulb, such that the user may selectively activate the light emitting bulb in accordance with his or her particular desires. It is also oftentimes desirable to have a night light which, without providing a high level of illumination, will significantly aid the user in safely locating objects (including the light switch for the light emitting bulb) within a darkened room. It is also known that electroluminescent light sources can provide a desired degree of light, in several different colors, with little power drain. Thus, while the prior art has generally appreciated both the desire to have a functional, low power drain, and aesthetically pleasing night light, it has not heretofore been known to utilize the advantageous features of an electroluminescent light source in conjunction with the circuitry to the light emitting bulb in order to provide a light fixture which combinedly includes the light emitting bulb and electroluminescent light source. 
     SUMMARY OF THE INVENTION 
     The present invention provides a light fixture which includes a light emitting bulb, at least one pair of conductors for connection to an electrical energy source (e.g., typically the household alternating current source), at least one electroluminescent light source, and a switch means for interconnecting these components. The electroluminescent light source, which may be of the type described in U.S. Pat. Nos. 3,069,579 and 5,485,355 is preferably an elongated flexible member which can be readily shaped into a desired configuration. The color of the light emitted by the electroluminescent light source when it is appropriately energized depends essentially on the type of electroluminophor powder used. 
     The electroluminescent light source includes a pair of conductive electrodes. In accordance with the present invention, one of the electrodes is in a circuit including the switch means which is connected between the light emitting bulb and the electrical energy source. The switch means is manually operative to selectively energize desired ones of the light emitting bulb and/or electroluminescent light source. The light fixture may advantageously be in the form of a table lamp. Various arrangements of the switch means and associated circuitry may be utilized such that (a) the electroluminescent light source will always be on when the unit is connected to an electrical energy source, with the switch means manually turning the light emitting bulb either on or off, or (b) the switch means can alternatively (i) turn the electroluminescent light source on, (ii) the light emitting bulb on, (iii) both the electroluminescent light source and light emitting bulb on, or (iv) both electroluminescent light source and light emitting bulb off. 
     The electroluminescent light source which is preferably an elongated flexible member, may include a plurality of such individual electroluminescent light sources, each emitting a different color when suitably energized. 
     As a further feature of the present invention, a photoelectric cell may be included in the circuitry which includes the electroluminescent light source. The photoelectric cell will function to only permit the electroluminescent light source to be turned on in a darkened room. Thus, if the electroluminescent light source portion of a light fixture is intended to serve as a night light, it will not be energized during daylight conditions. This results in reduced power drain and longer life. 
     Accordingly, it is the primary object of the present invention to provide a light fixture which advantageously combines the functions of a light emitting bulb and electroluminescent light source. 
     A further object of the present invention is to provide such a light fixture in which the electroluminescent light source will provide a minimal power draw night light. 
     An additional object of the present invention is to provide such a light fixture which includes a manually operable switch means for the user to selectively energize desired ones of the light emitting bulb and/or electroluminescent light source. 
     Yet a further object of the present invention is to provide such a light fixture which includes a photoelectric cell such that the electroluminescent light source night light will only be energized in a darkened environment. 
     These as well as other objects of the present invention, will become apparent upon a description of the following drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of one form of a table lamp light fixture in accordance with the present invention. 
     FIG. 2 is a circuit diagram of the light fixture shown in FIG.  1 . 
     FIG. 3 is a perspective view of another form of light fixture, shown as a desk set, which may be electrically similar to the embodiments of FIGS. 1 and 2. 
     FIG. 4 is a perspective view of another embodiment of a table lamp in accordance with the present invention. 
     FIG. 5 is a circuit diagram of the table lamp shown in FIG.  4 . 
     FIG. 6 is a circuit diagram operationally similar to FIG.  2 . 
     FIG. 7 is an alternate circuit diagram in which the switch either only turns the electroluminescent light source on, or turns only the light emitting bulb on. 
     FIG. 8 is a modification of the circuit shown in FIG. 7, which further includes a photoelectric cell in conjunction with the energization of the electroluminescent light source. 
     FIG. 9 is a modification of the circuit shown in FIG. 7 in which the switch includes an additional position for turning both the electroluminescent light source and light emitting bulb off. 
     FIG. 10 is a modification of the circuit shown in FIG. 7, which includes three electroluminescent light sources in electrical parallel connection. 
    
    
     DETAILED DESCRIPTION 
     Reference is initially made to FIGS. 1 and 2 which illustrate one form of a combined table lamp and night light  15  in accordance with the present invention. It includes a conventional socket  12  for the reception of a bulb  10  and an on/off switch  14 . A plurality of electroluminescent light sources  60 - 1 ,  60 - 2 ,  60 - 3 ,  60 - 4 ,  60 - 5 , and  60 - 6  are incorporated within elongated central post-like member  16 . The lamp  15  further includes a base  42 , decorative transparent enclosure  44 , and upper decorative disk like member  46 . Although six such electroluminescent light sources are shown, in parallel electrical connection, a different number may be used. Each of the electroluminescent light sources is preferably of the type shown in U.S. Pat. Nos. 5,485,355 and 3,069,579 and includes a central wire  50  which serves as the internal electrode. An electroluminescent layer coats this wire, with an external transparent electroconductive layer overlaying the electroluminescent layer. A wire  100  which is substantially thinner than central wire  50  is in contact with the transparent electroconductive layer by being wound thereover. Wire  100  serves as the second external electrode of the electroluminescent light source. Each individual electroluminescent light source ( 60 - 1  through  60 - 6 ) is coated with a transparent protective polymer layer so as to provide an elongated flexible cable which is generally in the order of 1.0-3.0 mm in diameter. When the internal and external electrodes are connected to an alternating current power source  20 , as by supply line wires  30 ,  40 , the electroluminescent light source will emit light over its entire length, uniformly in all directions. As is well known, the color of the light can be changed by the selection of electroluminophor powder used, and dyes added to the polymer protective layer. Advantageously, a resistor  32  which may typically be in the order of 10,000 to 100,000 ohms, may be inserted within the circuit. The utilization of the resistor significantly reduces the risk of potential damage to the electroluminescent light source which might result from voltage spikes in the system or other types of fast electrical transients that could occur in the supply voltage  20 . 
     It should thus be appreciated that when the lamp  15  is connected to the power source  20 , as by plug  31  at the end of supply line wires  30 ,  40 , all six of the electroluminescent light sources  60 - 1  through  60 - 6  will be energized. The light emitting bulb  10  may then be selectively energized by the manual movement of switch  14  of the bulb socket  12 . 
     Reference is now made to FIG. 3 which shows another embodiment of the light fixture, in the form of a desk set  25 . The desk set includes a base  43  having receptacles  45 , typically for the insertion of a pen and pencil (not shown). The light fixture portion thereof is provided by gooseneck type transparent element  48 , which includes an electroluminescent light source  60  contained therein, with the light emitting bulb (not shown) being within shield portion  47 . The electroluminescent light source  60  will preferably include a plurality of elongated electroluminescent light sources, such as  60 - 1  through  60 - 6  of the prior embodiment. The switch  14 - 1  corresponding to switch  14  of the embodiment shown in FIG. 1, is located within the base  43 . Thus, when the desk set  25  is connected to the power source  20 , the electroluminescent light source  60  will be energized, with switch  14 - 1  then being manually controlled to selectively turn the light emitting bulb on or off. 
     Reference is now made to FIG. 4 which shows another embodiment of a table lamp, and in which those components corresponding to similar components of the embodiment shown in FIG. 1 are indicated by the same numerals with a prime suffix. The circuit in FIG. 5 for the light fixture shown in FIG. 4 differs from the prior embodiments in that an additional switch  70  is provided for the electroluminescent light sources  60 - 1 ′ through  60 - 5 ′. That is, the electroluminescent light sources  60 - 1 ′ through  60 - 5 ′ may be independently turned on or off by switch  70  such that the electroluminescent light sources  60 - 1 ′ through  60 - 5 ′ may be either energized or de-energized, when switch  14 ′ is in either of its two positions (for energizing or de-energizing the light emitting bulb  10 ). 
     FIG. 6 similarly corresponds to FIG. 2, but shows two electroluminescent light sources  60 ,  65  connected in parallel and continually energized by voltage source  20 , via supply line wires  30 ,  40 . Electroluminescent light source  65  includes internal electrode  55  and second external electrode  105 . The switch  14  is manually operable to selectively energize light emitting bulb  10 . 
     FIG. 7 is a modification of the circuit, shown with only one electroluminescent light source  60  (although it should be understood that additional electroluminescent light sources may be connected thereto in parallel arrangement, as shown in the prior embodiments). The switch  80  is shown as a two position switch. When the common arm  82  is connected to terminal  83 , as shown in FIG. 7, only the electroluminescent light source  60  will be energized. When the common arm  82  of the switch is connected to terminal  84 , only the light emitting bulb  10  will be energized. Thus, the circuit in FIG. 7 selectively energizes either the electroluminescent light source  60  or light emitting bulb  10 . 
     FIG. 8 is a variation of the circuit shown in FIG. 7. A photosensitive cell  95  is added in the circuit to the electroluminescent light source  60 . This advantageously will limit the completion of the circuit to, and hence energization of, the electroluminescent light source  60  only under darkened ambient conditions. 
     FIG. 9 is a modification of the circuit shown in FIG. 7, in that switch  80 ′ includes an additional position  85 . When the common arm  82  is connected to switch terminal  85  neither the electroluminescent light source  60  or light emitting bulb  10  will be energized. Thus, this circuit selectively energizes either the electroluminescent light source  60 , light emitting bulb  10 , or neither of them. 
     FIG. 10 corresponds to the circuit of FIG. 7, but shows three electroluminescent light sources  60 ,  62 , and  64  (having conductors  50 ,  100 ;  52 ,  102 ;  54 ,  104 , respectively) connected in parallel. 
     It is therefore seen that the present invention provides a light fixture in which one or more electroluminescent light sources are combined with the light emitting bulb. This advantageously permits the unit to operate as a night light in addition to a source of more substantial illumination. Several embodiments are provided to selectively control the functioning of the light emitting bulb and electroluminescent light source. 
     While several preferred embodiments of the present invention have been described in detail, various modifications, alterations, and changes may be made thereto without departing from the spirit and scope of the present invention as defined in the following claims: