Abstract:
A lighting device ( 10, 11 ) including:  
     (a) a light source,  
     (b) a distal light scattering means,  
     (c) a transparent or translucent surface,  
     (d) the distal light scattering means being disposal at a distance away from the light source and outside said housing ( 60 ),  
     (e) the distal light scattering means becomes generally luminous when illuminated by the light source, and  
     (f) the light source being surrounded by a housing ( 60 ) including at least a transparent or translucent surface.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to luminescent devices, means and apparatus and, more particularly, to electroluminescent devices, means and apparatus. More specifically, although of course not solely limited thereto, this invention relates to decorative electroluminescent devices.  
         BACKGROUND OF THE INVENTION  
         [0002]    Lighting devices, especially electroluminescent devices or apparatus are widely used for generally lighting purpose as well as a means of decoration. A typical lighting device includes a light-emitting source, such as a light bulb or a fluorescent tube, to produce the necessary luminosity. The light can then be directed towards a scattering body, for example, a crystal ball, to produce more or secondary decorative lighting effects.  
           [0003]    However, conventional ways for producing decorating lighting effects are somewhat limited. It will be desirable if there can be provided means, device or apparatus for producing or improving decorative lighting effects. It will be highly desirable if such lighting effects are remarkable or interesting while do not require very complicated arrangements. Furthermore, with the rapid improvements in light-emitting diodes (LEDs) recently, LEDs have become a viable choice for use in lighting devices and apparatus, whether for decorative purpose or for basic general lighting needs. Hence, it will be desirable if there can be provided improved lighting devices, especially decorative lighting apparatus, with LED light sources.  
         OBJECT OF THE INVENTION  
         [0004]    Accordingly, it is an object of the present invention to provide improved lighting means, devices and apparatus. Specifically, it is an object of this invention to provide improved electroluminescent decorative lighting means, devices and apparatus. In addition, the lighting effects will be interesting or remarkable and can be effected without expensive or complicated arrangements. More specifically, it is an object of the present invention to provide electroluminescent lighting devices, means and apparatus including light-emitting diodes as a light source. At a minimum, it is an object of this invention to provide the public with a useful choice of electroluminescent lighting devices, means and apparatus.  
         SUMMARY OF THE INVENTION  
         [0005]    According to the present invention, there is provided . . .  
           [0006]    According to another aspect of this invention, there is provided . . . 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    Preferred embodiments of the present invention will be explained in further detail below by way of examples and with reference to the accompanying drawings in which:— 
         [0008]    [0008]FIG. 1 is a perspective view of a decorative electroluminescent lighting device of a first preferred embodiment of the present invention,  
         [0009]    [0009]FIG. 2 is an exploded view of the lighting device of FIG. 1,  
         [0010]    [0010]FIG. 3 is a longitudinal cross-sectional view of the lighting device of FIG. 1,  
         [0011]    [0011]FIG. 3A shows an enlarged cross-sectional view of the light-emitting diode lighting source of FIG. 3,  
         [0012]    [0012]FIG. 4 is a longitudinal cross-sectional view of a second preferred embodiment of a lighting device of the present invention, and  
         [0013]    [0013]FIG. 5 is an exploded view of the lighting device of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    Referring to FIGS.  1  to  3 , there is shown a first preferred embodiment of the present invention in the form of an electroluminescent lighting device  10 . The lighting device  10  includes a head portion  20 , a neck portion  30  and a base portion  40 . The lighting device  10  also includes a light source  50 , a distal light scattering means  60  and an optical guide  70  interconnecting the light source  50  and the distal light scattering means  60 . The light source  50  is generally surrounded by part of the base housing  41  which includes at least a transparent or translucent window or surface. The distal light scattering means  60  includes a light scattering body  61  which, when placed along the path of a light beam, will scatter or deflect the light beam into a plurality of beams along a plurality of orientations or directions. In this example, the light scattering body  61  includes a generally spherical body made of a clear and transparent material such as, plastics, glass or crystal. In addition, the light scattering body  61  has a relatively high refractive index. The outer surface of the light scattering body  61  is extensively faceted to enhance the optical scattering, diffraction or deflection characteristics. In order to provide a more versatile or sophisticated distal light scattering means, the inside of the light scattering body  61  is generally hollow with an intermediate light scattering member  62  disposed inside. This intermediate light scattering body  62  includes a coloured body, which is generally transparent or translucent, to provide additional visual complexity to the distal light scattering means. In addition, the intermediate light scattering body may include a multi-coloured body formed by mosaicing a plurality of coloured bodies to form a multi-coloured scattering means. To minimize the adverse attenuation of light due to the intermediate light scattering body, this light body is also thin and hollow with a light receiving aperture  63  aligned towards the light source  50 . Furthermore, the upper portion of the intermediate light scattering body  62  in this example resembles a bulb or a burning flame so that the lighting device will have a general appearance of a burning candle and the bulb-shaped body is formed by two coloured parts which, together, resemble a burning flame. In general, the light scattering phenomena effected by the distal light scattering means will be a combined effect of the first light scattering body  61  and the intermediate light scattering body  62 .  
         [0015]    The optical guide  70  generally provides an optical path for the light emitted by the light source  50  to travel towards the distal light scattering means  60 . In this specific embodiment, the optical guide  70  includes an elongated hollow tubular member generally extending between the light source and the distal light scattering means. The cylindrical wall of the hollow tubular member  71  generally surrounds the light which travels from the light source towards the distal light scattering means. In this specific example, the hollow tubular member is substantially transparent and the transit of light between the light source  50  disposed at the base portion and the distal light scattering means  60  at the head portion  20  is generally unnoticeable or just marginally observable along the length of the hollow tubular optical guide. Consequently, the lighting device  10  appears to include two light separate sources while, remarkably, there is only a single light source disposed in the base portion  40  of the lighting device  10 . The hollow tubular member further includes a first and a second radially extending collar members at its distal ends. The upper collar member  72  provides a more comfortable seat for the distal light scattering means while the lower collar member  73  provides a more stable connection to the base portion  40  of the lighting device  10 .  
         [0016]    Turning now to the arrangement of the light source  50 , the light source  50  includes a light-emitting member  51  which, in this specific example, is a packaged LED. As shown in FIG. 3A, the packaged LED  51  includes a light-emitting element which is the actual light-emitting diode, a light reflector  53  and a light diffusing member  54 . The light reflector  53  of a packaged LED is generally designed and adapted to reflect a portion of the light generated by the light-emitting diode along a prescribed direction with certain viewing angles. The viewing angle is a general measure of the spread or divergency of the beam emerging from the light-emitting diode. The light diffusing body  54  includes a substantially clear and transparent body which is generally cylindrical with a rounded head portion, or more specifically, a dome-shaped head portion.  
         [0017]    The design and configuration of this light diffusing body  54  allows a portion of the light generated by the light-emitting diode to travel towards the rounded head portion and exit along the prescribed direction  55 . In addition, as the light diffusing body  54  is made of a transparent material with a relatively high refractive index, a portion of the generated and reflected light will be deflected or refracted sideways generally along the directions  56  due to the rounded or dome-shaped profile of the head portion of the light diffusing body  54 . As a result, light emerges along the prescribed direction  55  as well as sideways along the directions  56 . By disposing the light-emitting member  51  at the base portion  40 , with the axis of the cylindrical body or the rounded head aligned along the longitudinal axis  72  of the hollow tubular member and towards the distal light scattering means  60 , the distal light scattering means will be luminous when the light-emitting member  51  is turned on to emit light.  
         [0018]    At the same time, the light-emitting member  51  is surrounded by a housing portion which includes at least a transparent or a translucent window or surface. When the light-emitting member  51  is turned on, light generated by the light-emitting diode  52  and will also be deflected sideways generally along the directions  56  due to the diffusing refraction or scattering characteristics of the light diffusing body  54 . As a result, the transparent or translucent surface of the base housing  41  will also be luminous or glowing. Hence, with the above arrangements, a very remarkable and interesting phenomenon that two substantially optically separated luminescent portions can be produced by means of a single light-emitting source. In the present specific example, the light-emitting member  51  is further surrounded by a translucent body  57  to smoothen the light emitted along the directions  56  by diffusion, diffraction or even scattering by the translucent member  57 . The translucent member  57  in this example includes a generally parabolic member with its parabolic axis aligned towards the distal light scattering means  60 .  
         [0019]    Referring to FIG. 3, the light generated by the light-emitting member  51  which travels towards the distal light scattering means  60  will enter the optical guide  70  through the entry aperture  73 . It will be noted that the entry aperture  73  is generally larger than the projection of the head portion of the light-emitting member along its cylindrical axis. Furthermore, focusing or collimating means  73  is disposed intermediate of the optical guide  70  and the light-emitting member  51  in order to collimate the light towards the distal scattering means  60 . The collimating means  73  in the present example includes a transparent plate with a rounded protrusion elevated above the rest of the plane. The rounded protrusion is shaped so that the diverging light travelling along the direction  55  will be collimated towards the light scattering member  61  to alleviate the portion of light which will escape away from the optical guide. Furthermore, batteries as well as driving circuitry for the LED are disposed within the base portion of the lighting device  10 .  
         [0020]    Referring to FIGS. 4 and 5 showing a second preferred embodiment of this invention, the lighting device  11  also includes a head portion  20 , a neck portion  30  and a base portion  40  with the base housing  41  which are generally identical to that of the lighting device  10  of the first preferred embodiment and therefore share the same reference numerals. In the specification below, parts or components which are generally identical or equivalent to that of the first preferred embodiment  10  will share the same reference numerals unless the context otherwise requires. In this preferred embodiment, the light-emitting member  51  is disposed inside the intermediate light scattering body  62  with its rounded head aligned towards the base portion  40  of the lighting device  11  and along the longitudinal axis of the optical guide  79 .  
         [0021]    The optical guide  79  is enclosed within the transparent hollow tubular member  71  and extends generally along the entire length of the hollow tubular member. When the light-emitting member  51  is turned on, light generated by the LED will travel from the head portion  20  towards the base portion  40  along the elongated optical guide  79 . The elongated optical guide  79  is substantially solid and cylindrical and is made of a light scattering material so that light travelling along the optical guide  79  will be scattered radially or sideways, thereby forming a glowing or luminescent phenomenon along the length of the optical guide  79 . In addition, the light diffusing or scattering effect of the optical guide  79  also means that the optical guide is generally light attenuating. As a result, the luminosity or degree of glowing will diminish as the light travel further away from the light source  50  which is disposed inside the head portion  20  of the lighting device  11 . With this arrangement, a very remarkable and interesting phenomena that the lighting device includes a luminescent light scattering body  61  as well as a luminescent rod with a distributed lighting effect. In this arrangement, length of gradually diminishing light can be observed along the generally luminescent rod. To ensure that a substantial portion of the light generated by the light source  50  will be transmitted to the optical light guide  79 , a generally transparent reflector with a rounded or parabolic reflective surface is disposed adjacent to the light-emitting diode with the rounded head of the light-emitting diode  52  disposed away from the reflective surface of the reflector  59 . An example of a suitable elongated optical guide  79  is a plastic rod doped or dispersed with a light scattering medium, such as a fluorescent powder.  
         [0022]    While the present invention has been explained by reference to the preferred embodiments described above, it will be appreciated that the embodiments are only illustrated as examples to assist understanding of the present invention and are not meant to be restrictive on its scope. In particular, the scope, ambit and spirit of this invention are meant to include the general principles of this invention as inferred or exemplified by the embodiments described above. More particularly, variations or modifications which are obvious or trivial to persons skilled in the art, as well as improvements made on the basis of the present invention, should be considered as falling within the scope and boundary of the present invention.  
         [0023]    Furthermore, while the present invention has been explained by reference to candle-light light devices, it should be appreciated that the invention can apply, whether with or without modifications, to other luminous means, devices and apparatus without loss of generality.