Abstract:
A night light includes an electro-luminescent element connected to an electrical plug by conductive elements compressed between electrodes of the electro-luminescent element and prongs of the electrical plug. The electro-luminescent element is captured between an inner plate and a front part of the housing so as to cause the electro-luminescent element to conform to a curved surface of the housing without the need for additional plastic housing material, the inner plate also serving to apply a biasing force against the conductive elements.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 08/910,202, filed Aug. 13, 1997, which is a continuation-in-part of allowed U.S. patent application Ser. No. 08/383,404, filed Feb. 3, 1995, (now U.S. Pat. No. 5,667,394). 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an improvement to a night light of the type having an electro-luminescent lighting element, as disclosed in parent U.S. patent application Ser. No. 08/910,202, in which large area electrodes on the electro-luminescent lighting element directly engage a specially designed connection member to facilitate electrical connection of the lighting element to a metal plug. The improvement involves the use of a multiple-piece housing which provides a curved surface while minimizing the amount of plastic required. 
     2. Discussion of Related Art 
     The present invention utilizes the basic electro-luminescent lighting fixture connector principles disclosed in copending allowed U.S. patent application Ser. No. 08/383,404, (now U.S. Pat. No. 5,667,394) applied to a night light of the type disclosed in parent U.S. patent application Ser. No. 08/910,202, by utilizing a non-penetrative contact arrangement which limits damage to the electro-luminescent element(s) used in the night light and reduces the risk of electrical shocks and short circuits, and in addition addresses a problem with prior electro-luminescent night lights, such as the one disclosed in U.S. Pat. No. 5,662,408, that if the two-piece housing of the prior night lights is designed with a curved electro-luminescent panel, so as to provide a greater viewing angle and a more attractive housing configuration, while still providing a flat back surface to permit the night light to be flush with an electrical outlet when plugged in, the amount of plastic material required by the back piece of the housing must be increased in order to provide the necessary curved electro-luminescent element supporting surface. As a result, the prior two-piece housing construction is not practical for an electro-luminescent night light having a curved surface. 
     Except for the arrangement of the housing, the night light of the present invention is similar to that disclosed in the parent application. Since the advantages of the non-penetrative or sandwich type contact termination arrangement are described in detail in the parent application, they will not be repeated herein, except to note that non-penetrative contact termination, and in particular the use of resilient conductive members to provide the electrical connection between the prongs and large area electrodes provided on the surface of the electro-luminescent element, serves to simplify assembly and tooling by increasing the tolerances necessary to effect a good electrical connection, while increasing reliability and decreases risks of short-circuiting or electrical shock hazards. 
     The only prior disclosure of non-penetrative contact techniques to an electro-luminescent night light known to the Inventor is found in the above-cited U.S. Pat. No. 5,662,408, issued on Sep. 2, 1997. This patent discloses a low profile night light which relies on direct engagement between the outlet prongs and terminals extending from the electro-luminescent element. 
     While in one embodiment, shims are used to bias the prongs against the terminals, with the terminals being positioned between the shims and the terminals, none of the embodiments uses resilient conductive elements positioned between the prongs and large area terminals or electrodes on the surface of the electro-luminescent element, as in the present invention or that described in the parent application. As a result, in addition to failing to provide a practical way to support the electro-luminescent element to provide a curved surface, the night light disclosed in U.S. Pat. No. 5,662,408 provides a less secure higher impedance electrical connection, greater risk of short-circuits and electrical shock, and decreased assembly tolerances, particularly in view of the delicate nature of the terminal extensions required to effect the electrical connection to the outlet prongs. 
     SUMMARY OF THE INVENTION 
     It is accordingly an objective of the invention to provide a night light utilizing an electro-luminescent element having simplified assembly, low materials costs, increased reliability, and a reduced risk of short circuits and electric shock, and which includes a housing having a curved surface for enhanced visibility and a more attractive configuration. 
     This objective of the invention is achieved, in accordance with the principles of a preferred embodiment of the invention, by providing a night light in which an electrical connection between electrodes on the electro-luminescent element and a source of electric power is optionally provided by resilient conductive elements which provide a self-biased electrical connection to the electrodes without the need for penetrative elements or movable elements, and which includes, in an especially preferred embodiment of the invention, a two-part housing, at least one part being curved, and at least one intermediate housing member in the form of at least one inner plate, the inner plate serving as a fixture means for causing the electro-luminescent element to maintain a curved shape, supporting the plug assembly, and biasing the prongs of the plug assembly against conductive members which serve to ensure a good electrical connection between the prongs and contacts on the electro-luminescent element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view illustrated the basic principle of utilizing a non-penetrative contact arrangement in a night light. 
     FIG. 2 is an exploded perspective view showing a variation of the night light illustrated in FIG.  1 . 
     FIG. 3 is an exploded perspective view of an electro-luminescent light assembly suitable for use in the night lights of FIGS. 1 and 2. 
     FIG. 4 is an exploded perspective view of a further variation of the night lights illustrated in FIGS. 1 and 2. 
     FIG. 5 is a perspective view of an assembled night light corresponding to the night lights illustrated in FIGS. 1 and 4. 
     FIG. 6 is a perspective view of an assembled night light corresponding to the night light of FIG.  2 . 
     FIG. 7 is a perspective front view of a night light which utilizes the principles illustrated in FIGS.  1 - 6 , but which incorporates a curved surface in accordance with the principles of an especially preferred embodiment of the invention. 
     FIG. 8 is an exploded perspective rear view of a front portion of the night light illustrated in FIG.  7 . 
     FIG. 9 is an exploded perspective rear view showing both the front and rear portions of the night light illustrated in FIG.  7 . 
     FIG. 10 is an exploded perspective rear view of a variation of the night light illustrated in FIG.  7 . 
     FIG. 11 is a perspective view of a variation of the contact arrangement utilized in the night lights of FIGS.  7 - 10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As illustrated in FIG. 1, a night light constructed in accordance with the principles described in the parent application, and which is disclosed herein in order to illustrate the basic connector arrangement used by the present invention, includes an electro-luminescent element  14  made up of multiple phosphor segments  15  and electrode contact areas  16  (which are actually on the rear side of elements  16  extending from panel  14 ). The housing for the night light includes a rear section  17  containing an indentation for receiving the electro-luminescent element  14  and openings  18  for prongs  19 , and a front section  20  having an opening or window  21  through which the electro-luminescent element is to be viewed. An optional frontsheet  22  may be positioned between the electro-luminescent element  14  and window  21 . 
     In order to greatly simplify assembly of the night light of FIG. 1, contact areas  16  and prongs  19  are electrically connected together by means of resilient conductive elements  23  which are compressed between the contact areas and prongs when the housing is assembled together. Compression of the conductive elements  23  ensures that electrical continuity between the electrodes of the electro-luminescent element and the prongs is maintained, with the resilience of the conductive elements also compensating for tolerances in the construction of the prongs or contact areas of the electrodes of the electro-luminescent element, for example in the case where the prongs and electrodes have facing surfaces that are not completely parallel, or not completely flat. 
     The conductive elements  23  may be in the form of flexible or elastic conductive rubber elements, or conductive elements of similarly flexible and conductive plastic or metal material. Prongs  19  are UL-listed standard plugs, or equivalent plugs arranged to meet the requirements of countries other than the United States. 
     Preferably, rear housing section  17  and front housing section  20  are sealed together to prevent the night light from being opened and the electrical connections exposed. As will be explained in more detail below, additional housing pieces such as an inner plate can also be added for this purpose. The indentation in which the electro-luminescent element is received may of course have any desired configuration, or may be eliminated in favor of alternative electro-luminescent element holding means, and the means by which the housing sections are held together and/or sealed may include any suitable holding or sealing means, including glue, double-sided tape, press-fit posts, screws, melting, ultra-sonic sealing, hot melt adhesives, etc., resulting in an attractive and compact night light assembly similar to the one illustrated in FIG.  9 . 
     The electro-luminescent panel  14  may be of the type disclosed in U.S. Pat. No. 5,572,817 and copending U.S. patent application Ser. No. 08/729,408 (now U.S. Pat. No. 5,752,337), Ser. No. 08/734,872 (now U.S. Pat. No. 5,883,508), and Ser. No. 08/746,706 (now U.S. Pat. No. 5,806,960), in which attractive designs are obtained by including logos, figures, cartoon characters, words, on either the frontsheet  22  or the electro-luminescent element itself, either by printing, silk-screening, stencilling, or the like, and/or by appropriately arranging the phosphor segments of the electro-luminescent element. Alternatively, or in addition to electro-luminescent panel  14  the night light may include a three-dimensional tube  14 ′ arranged in an attractive pattern in the manner described in copending U.S. patent application Ser. No. 08/758,393. In the embodiment illustrated in FIG. 8, for example, a single color panel  14 ″ provides background for the illumination effect provided by the three-dimensional electro-luminescent element  14 ′, the other elements of the night light being the same as described in connection with FIG. 1, except that additional conductive resilient elements, for example having the configuration illustrated in parent U.S. patent application Ser. No. 08/383,404 (now U.S. Pat. No. 5,667,394), must be included in order to provide the necessary electrical connections. Further details of either the electro-luminescent panel or three-dimensional electro-luminescent element may be found in the above-cited patent and patent applications. 
     While in the arrangement of FIG. 1, the electro-luminescent panel is directly connected to the prongs of the night light outlet, it is also within the scope of the invention to use conductive member(s)  23 ′ to connect one or more electrodes of the panel to an inverter, control circuit, function interface, or the like, which can be in the form of a conventional circuit or an integrated circuit. Numerous suitable circuits are known and it is intended that the invention encompass any circuitry to which the electro-luminescent element might be connected, or no circuitry at all, with the electrodes of the electro-luminescent element being directly and exclusively connected to the prongs of the night light. By circuitry is meant any electrical component, including wires, resistors, capacitors, transistors, inductors, and so forth, as well as switches such as the illustrated photo-sensor  27 . 
     As shown in FIGS. 2 and 6, for example, the additional circuitry might be housed in an extension  36  of the rear housing member  25 . FIG. 2 also illustrates the variation in which the electro-luminescent element  26  does not have multiple segments, the decorative pattern being obtained instead by appropriate decoration of the frontsheet  27 . 
     Alternatively, in the variation shown in FIG. 3, the effects obtained by electro-luminescent element  28  and frontsheet  29  are enhanced by including an optical effects device  30  similar to the one described in copending U.S. patent application Ser. No. 08/841,624 and its parent U.S. patent application Ser. No. 08/489,160 (now abandoned), in which the image of the electro-luminescent element is enhanced by passage through a transparent transmission medium such as water, a gel, a solid transparent medium, epoxy, silicone, PVC, PC, acrylic, or the like to increase the apparent brightness of the element. The optical device can form a convex or concave lens, and can magnify the image, change the image location, change the focus, or change the color of emitted light in a simple and inexpensive yet effective manner. 
     The principles illustrated in FIGS.  1 - 6  are applied to a night light having a curved surface, as follows: 
     As illustrated in FIG. 7, the night light of the especially preferred embodiment of the invention differs from the night lights illustrated in FIGS.  1 - 6  in that, instead of a planar front surface, the front housing part  100  includes a curved surface  101  having a window or opening  102  through which one or more electro-luminescent elements may be viewed, with prongs  103  and  104  extending from a rear housing  105  and connected by means illustrated in FIGS.  8 - 11  to the electro-luminescent elements. In order to support an electro-luminescent element behind window or opening  102 , and also support prongs  103  and  104  and bias them relative to electrodes on the electro-luminescent element, the invention provides an additional housing piece, hereinafter referred to as an inner plate (not shown in FIG. 7, but illustrated as element  107  in FIGS.  8 - 10 ). It will be appreciated that other terms such as press-board would also be descriptive of the inner plate, and that members other than plates or boards could also be substituted in order to perform the same function. 
     FIG. 8 illustrates the assembly of the front portion of the night light shown in FIG.  7 . In this embodiment, the electro-luminescent element  106 , which may include any of the electro-luminescent elements disclosed in the prior patent documents cited above so long as they are sufficiently flexible to conform to the curved surface  101  of housing part  100 , is pressed flush against the rear of the front housing part by an inner plate  107  and positioned between posts  108  so as to be visible through window or opening  102 . The dimensions of window or opening are such that at least a portion of the electro-luminescent element extends beyond the edges of the window or opening to be supported by the front housing part in the area  128  denoted in FIG. 8 by hatching. 
     Pressing of the electro-luminescent element  106  against the front housing part  100  is accomplished by securing the inner plate  107  to the front housing part, with the electro-luminescent element sandwiched between the front surface of the inner plate and the rear surface of the front housing part using screws  109  or other fastening means, which pass through openings  110  and are threaded into posts  108 . While it is within the scope of the invention to secure the inner plate to the front housing by fasteners other than screws, such as an adhesive fastener, the use of screws is particularly advantageous because it permits the inner plate  107  to be disassembled from the front housing in order to replace a defective or damaged lighting element. 
     The inner plate  107  serves not only to press the electro-luminescent element against the front housing part  100 , but also to bias contact extensions  111  and  112  of prongs  103  and  104  against respective resilient conductive elements  113  and thereby bias the conductive elements against large area electrodes  114  on the electro-luminescent element in order to establish an electrical connection between the prongs and the electrodes. This is accomplished by providing slots  115  and  116  in the inner plate having an area sufficient to allow passage of the rear portions  117  and  118  of the prongs, but not of the contact extensions  111  and  112 , which as a result are engaged by the front surface of the inner plate and pressed against the resilient conductive elements  113  upon securing the inner plate to the front housing part. As a result, the arrangement of this embodiment greatly reduces the required thickness of the back housing piece and reduces the overall weight of the night light, and in addition permits the prong length from the back housing to the inner plate to be varied so that other devices can be connected, such as a power fail switching circuit or other functional components. 
     As illustrated in FIG. 9, the housing of this preferred embodiment of the invention is completed by securing rear housing part  105  to the front housing part  100  following attachment of the inner plate  107  to thereby capture the electro-luminescent element  106  and press the contact extensions  111  and  112  of prongs  103  and  104  against resilient conductive elements  113 , in turn pressing resilient conductive elements  113  against electrodes  114  of the electro-luminescent element. Rear housing part  105  includes, in this embodiment, slots  119  and  120  through which rear portions  117  and  118  of prongs  103  and  104  extend to the exterior of the housing for engagement with contacts of a standard electrical outlet, and openings  119  for screws  120  which are used to removably fasten the rear housing part to the front housing part by means of threaded posts  121  in the front housing part (these posts are omitted from FIG.  8 ). As with the screws  109 , it is within the scope of the invention to substitute other fastening means, including adhesive fasteners, but screws are especially preferred because they enable disassembly of the night light in order to replace defective or damaged electro-luminescent elements. 
     In the variation of the especially preferred embodiment of the invention illustrated in FIG. 10, the electro-luminescent element is indirectly connected to the prongs of the night light outlet by circuitry housed within an extension or attachment  122  to the inner plate  107  in a manner similar to that illustrated in FIGS. 2 and 6. Again, the circuitry can be in the form of one or more elements selected from the group consisting of an inverter, control circuit, function interface, or the like, which can be in the form of a conventional analog or digital circuit, or an integrated circuit, numerous examples of which are known, the extension or attachment  122  including appropriate terminals or contacts for engaging the  103  and  104  and respective conductive members  113  in order to establish an electrical connection therewith. Of course, the embodiments illustrated in FIGS.  7 - 10  can also be used with an optical effects device similar to device  30  illustrated in FIG.  3  and described above. 
     The contact arrangement shown in FIGS.  7 - 10  may be modified to provide additional receptacles in the manner described in copending application Ser. No. 08/925,122, filed Sep. 8, 1997, and incorporated herein by reference. An example of a multiple receptacle contact arrangement is illustrated in FIG. 11, in which the prongs are connected to, or integral with, conductive strips  123  and  124 , which in turn are provided with multiple receptacle contacts  125 . 
     Finally, it will be appreciated by those skilled in the art that the front housing may include decorations or design features in addition to the illustrated simple curved surface, and that additional pieces may be added to the front housing part  100  in order to enhance the design. 
     Having thus described a preferred embodiment of the invention and a number of different variations and modifications of the preferred embodiment, it is anticipated that still further variations and modifications will undoubtedly occur to those skilled in the art upon reading the above description, and it is therefore intended that the invention be interpreted solely in accordance with the appended claims.