Abstract:
A lighting device includes a light source and an enclosure enclosing the light source wherein a portion of the enclosure has a focus-forming curvature such that when the light from the light source is reflected off the enclosure element the reflected light intersects at the focus of the curvature and creates a virtual light source at the focus. A reflective coating or a reflective material may be applied to the enclosure, or a ball lens may be used around the light source, to increase the intensity of the reflected light and of the virtual light source. A diffuser may be used to change the size and shape of the virtual light source.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to lighting devices and more particularly to a lighting device, in which the light emitting from its light source is reflected off an enclosure element to form a virtual light source. 
         [0003]    2. Description of the Related Art 
         [0004]    Lighting devices are classified into two categories, direct lit or indirect lit, depending on whether the illumination of the lighting devices comes directly from the light source of the devices or indirectly from a reflector. Most lighting devices, such as candle, incandescent, halogen, and LED lamps are direct-lit lighting devices, with or without an optical filter or lens. Fluorescent lamps are also considered direct-lit lighting devices since the light comes directly from the lighting surface of the fluorescent lamps. In contrast, indirect-lit lighting devices provide illumination by using a reflecting mechanism to reflect the light from the light source of the lighting device off a reflecting mechanism, often in a direction opposite to the original lighting direction of the light source. 
         [0005]    The present invention combines at least one light source and one enclosure element wherein at least one portion of the enclosure element has a focus-forming curvature such that when the light from the light source is reflected off the enclosure element the reflected light intersects at the focus of the curvature and creates a virtual light source at the focus. The virtual light source which is created off the reflected light becomes a new direct-lit light source. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention combines at least one light source and one enclosure element whereas at least one portion of the enclosure element. The present invention is characterized by that at least one portion of the enclosure element takes on the geometric shape of a focus-forming curvature so that when the light from the light source is reflected off the focus-forming portion of the enclosure element, the reflected light intersects at the focus of the geometric shape and creates a virtual light source at that focus. This virtual light source of the lighting device becomes the new light source for illumination, rather than the original light source. 
         [0007]    Two examples of focus-forming geometric shape for forming virtual light source are ellipsoid and paraboloid. With an ellipsoid, the original light source of the lighting device is placed at one of the two focuses of an ellipsoid and thus creates the virtual light source at the other focus of the ellipsoid. With a paraboloid, multiple original light sources are placed at any positions on the open end of the paraboloid, and the reflected light intersects at the focus of the paraboloid. 
         [0008]    In one aspect of the present invention, an optical lens is placed between the light source and the focus of the focus-forming curvature of the enclosure element such that the optical lens changes the lighting angle of the light source and subsequently changes the shape and size of the intersection of the light reflected off the focus-forming curvature. In this case, the reflected light intersects at a focus region, rather than a focus point, and the size and shape of the focus region is determined by the design of the optical lens. 
         [0009]    One type of optical lens that is used for changing the shape and size of the intersection region of the reflected light is a diffuser lens. A diffuser lens has the effect of widening the lighting angle of the original light source and results in extending the intersection region of the reflected light from the focus of the focus-forming curvature of the enclosure element toward the light source. 
         [0010]    In another aspect of the present invention, a reflective means is used on the focus-forming curvature of the enclosure element for increasing the light reflection off the enclosure element and subsequently enhancing the intensity of light that intersects at the focus. In one embodiment, the reflective means is implemented via the application of a reflective coating on the portion of the enclosure element with the focus-forming curvature. In another embodiment, the reflective means is implemented by using a reflective material to fabricate the portion of the enclosure element with the focus-forming curvature. In yet another embodiment, the reflective means is implemented by placing a curved mirror adjacent to the portion of the enclosure element with the focus-forming curvature for light reflection. 
         [0011]    In another aspect of the present invention, a reflective means is placed at the focus of the focus-forming curvature of the enclosure element to redirect the reflected light that intersects at the focus. In one embodiment, the reflective means is implemented by a mirror ball for creating a uniform reflecting effect. In another embodiment, the reflective means is implemented via a reflector of a particular shape and pattern so as to create a non-uniform reflecting effect. 
         [0012]    In another aspect of the present invention, a light collecting means is placed between the light source and the enclosure element such that the light from the light sources is collected by the light collecting means and redirected toward the focus-forming curvature with the effect of increasing the intensity of light that intersects at the focus of the curvature. One embodiment of the light collecting means is a ball lens. By covering the light source with a ball lens inside a paraboloidal enclosure element, the light from the light source will be redirected in the direction that is parallel to the axis of the paraboloid, thus increasing the amount of light that will be reflected off the enclosure element and intersect at the focus of the paraboloid. 
         [0013]    Another embodiment of the light collecting means is to use a paraboloidal reflector behind the light source such that any portion of the light emitting away from the focus of the focus-forming curvature is collected and redirected by the paraboloidal reflector toward the virtual light source. 
         [0014]    The present invention differs from the prior art in that it is neither direct-lit nor indirect-lit. Rather, it uses a portion of the enclosure element with a focus-forming curvature such that the light emitting from the original light source and reflected off the enclosure intersects at or around the focus of the curvature and the intersection of the reflected light becomes the new virtual light source of the lighting device. 
         [0015]    The claims and advantages will be more readily appreciated as the same becomes better understood by reference to the following detailed description and the accompanying drawings showing exemplary embodiments, in which like reference symbols designate like parts. For clarity, various parts of the embodiments in the drawings are not drawn to scale. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  schematically depicts an embodiment of the present invention wherein a light source is placed at one focus of an ellipsoidal enclosure and a virtual light source is created at the other focus of the corresponding ellipsoid. 
           [0017]      FIG. 2  schematically depicts an embodiment of the present invention wherein multiple light sources are placed at the open end of a paraboloidal enclosure and a virtual light source is created at the focus of the corresponding paraboloid. 
           [0018]      FIG. 3  schematically depicts an embodiment of the present invention wherein a light source is placed at one focus of an ellipsoid, a diffuser lens is placed between the light source and the other focus of the ellipsoid, and a virtual light source is created at the other focus of the ellipsoid extending toward the light source. 
           [0019]      FIG. 4  schematically depicts an embodiment of the present invention wherein a reflective means is used on the focus-forming curvature of the enclosure element for increasing the light reflection off the enclosure element. 
           [0020]      FIG. 5  schematically depicts an embodiment of the present invention wherein a reflective means is placed at the focus of the focus-forming curvature of the enclosure element to redirect the reflected light that intersects at the focus. 
           [0021]      FIG. 6  schematically depicts an embodiment of the present invention wherein the light source is covered with a ball lens inside a paraboloidal enclosure element for collecting and redirecting the light in the direction parallel to the central axis of the paraboloid with the effect of increasing the intensity of reflected light that intersects at the focus of the paraboloid. 
           [0022]      FIG. 7  schematically depicts an embodiment of the present invention wherein the light source has 360 degree lighting angle and a paraboloidal reflector is placed behind the light source for collecting and redirecting the light in the direction parallel to the central axis of the paraboloid and toward the focus forming curvature with the effect of increasing the intensity of reflected light that intersects at the focus of the paraboloid. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Various implementations of the present invention and related inventive concepts are described below. It should be acknowledged, however, that the present invention is not limited to any particular manner of implementation, and that the various embodiments explicitly discussed herein are primarily for purposes of illustration. For example, the various concepts discussed herein may be suitably implemented in a variety of luminaires having different form factors and light output. 
         [0024]      FIG. 1  illustrates one non-limiting example of a lighting device according to one embodiment of the present invention. The lighting device  100  includes a light source  120  and an ellipsoidal enclosure element  110 . The light source  120  is placed at one focus of the corresponding ellipsoid. The light  130 A and  130 B emitted from the light source  120  partially passes though the enclosure element  110  and partially reflects off the enclosure element  110 . The partially reflected light  140 A and  140 B intersects at the other focus  150  of the ellipsoid due to the nature of the ellipsoid. The light intersecting at the other focus  150  becomes a virtual light source. 
         [0025]      FIG. 2  illustrates another non-limiting example of a lighting device according to one embodiment of the present invention. The lighting device  200  includes multiple light sources  220 A and  220 B and a paraboloidal enclosure element  210 . The light  230 A and  230 B emitted from the light sources  220 A and  220 B parallel to the axis  211  of the corresponding paraboloid partially passes through the enclosure element  210  and partially reflects off the enclosure element  210 . The partially reflected light  240 A and  240 B intersects at the focus  250  of the paraboloid due to the nature of a paraboloid. The light intersecting at the other focus  250  becomes a virtual light source. It is noted that the paraboloid is an “elliptic paraboloid” as opposed to a “hyperbolic paraboloid”. 
         [0026]      FIG. 3  illustrates another embodiment of the present invention. The lighting device  300  includes a light source  320 , an ellipsoidal enclosure element  310 , and a diffuser lens  360 . The light source  320  is placed at one focus of the ellipsoid. When there is no diffuser lens  360 , the light  330 A and  330 B emitted from the light source  320  partially passes though the enclosure element  310  and partially reflects off the enclosure element  310 . The partially reflected light  340 A and  340 B intersects at the other focus  350  of the ellipsoid due to the nature of the ellipsoid. When a diffuser lens  360  is placed over the light source, the light  330 A and  330 B from the light source is widened by the diffuser lens  360  to become  331 A and  331 B. The partially reflected light  341 A and  341 B of the light  331 A and  331 B now intersects at an area  351 , which starts from the focus  350  and extends toward the light source. The region  351  where the reflected light intersects becomes a virtual light source. 
         [0027]      FIG. 4  illustrates another embodiment of the present invention. The lighting device  400  includes a light source  420 , an ellipsoidal enclosure element  410 , and a reflective element  411 A and  411 B. The light source  420  is placed at one focus of the ellipsoid. The light  430 A and  430 B emitted from the light source  420  is completely reflected off the reflective means  430 A ad  430 B, and the reflected light  440 A and  440 B has the full intensity of the  430 A and  430 B. As a result, the reflected light that intersects at the other focus  450  of the ellipsoid has a higher intensity, thus creating a brighter virtual light source at the focus  450 . 
         [0028]      FIG. 5  illustrates another embodiment of the present invention. The lighting device  500  includes a light source  520 , an ellipsoidal enclosure element  510 , and a reflective means  550 . The light source  520  is placed at one focus of the ellipsoid and the reflective means  550  is placed at the other focus of ellipsoid. The light  530 A and  530 B emitted from the light source  520  partially passes through the enclosure element  510  and partially reflects off the enclosure element  510 . The reflected light  540 A and  540 B intersects at the other focus of the ellipsoid, which is where the reflective means  550  is positioned. So the reflected light  540 A and  540 B is further reflected to become  550 A and  550 B. The reflective means  550  becomes a reflective light source and it reflects light in the direction opposite to the light direction of the light source  520 . 
         [0029]      FIG. 6  illustrates another embodiment of the present invention. The lighting device  600  includes multiple light sources  620 A and  620 B, a paraboloidal enclosure element  610 , and a ball lens  660 . The light  630 A and  630 B emitted from the light sources  620 A and  620 B parallel to the axis  611  of the paraboloid partially passes through the enclosure element  610  and partially reflects off the enclosure element  610 . The partially reflected light  640 A and  640 B intersects at the focus  650  of the paraboloid due to the nature of a paraboloid. The light intersecting at the other focus  650  becomes a virtual light source. 
         [0030]    When a ball lens  660  is placed over the light source  620 B, it collects and redirects all light  670 A and  670 B from the light source  620 B toward the direction that is parallel to the axis  611  of the paraboloid, as illustrated by the light  680 A and  680 B. As a result, additional reflected light  690 A and  690 B intersects at the focus  650  of the paraboloid, with the net effect of increasing the intensity of the light of the virtual light source at the focus  650 . 
         [0031]      FIG. 7  illustrates another embodiment of the present invention. The lighting device  700  includes multiple light sources  720 A and  720 B, a paraboloidal enclosure element  710 , and a paraboloidal reflector  760 . The light  730 A and  730 B emitted from the light sources  720 A and  720 B parallel to the axis  711  of the paraboloid partially passes through the enclosure element  710  and partially reflects off the enclosure element  710 . The partially reflected light  740 A and  740 B intersects at the focus  750  of the paraboloid due to the nature of a paraboloid. The light intersecting at the other focus  750  becomes a virtual light source. 
         [0032]    The light  770 A and  770 B emitted from the light source  720 B in the direction away from the focus  750  is collected and redirected by the paraboloidal reflector  760  toward the direction that is parallel to the axis  711  of the paraboloid enclosure element, as illustrated by the light  780 A and  780 B. As a result, additional reflected light  790 A and  790 B intersects at the focus  750  of the paraboloid enclosure element, with the net effect of increasing the intensity of the light of the virtual light source at the focus  750 . 
         [0033]    While the invention has been described and illustrated in its preferred embodiments, it should be understood that departure therefrom may be made within the scope of the invention, which is not limited to the specific details disclosed herein. Furthermore, it should be understood that the features of illustrated embodiments can be combined in any way, form, or fashion, to create another embodiment.