Patent Publication Number: US-2013250572-A1

Title: Lighting apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101109659 filed in Taiwan, Republic of China on Mar. 21, 2012, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a lighting apparatus and, in particular, to a lighting apparatus that is transflective. 
     2. Related Art 
     As the progressive of technology, the lighting apparatus has become one of the indispensable devices in our life. The lighting apparatus is initially composed of a tungsten bulb but now a light-emitting diode (LED). LED has the advantages of lower power consumption, smaller size and higher brightness. 
       FIG. 1  is a schematic diagram of a conventional lighting apparatus  1 . The lighting apparatus  1  include a LED unit  11  and a light-guiding rod  12  for guiding the light beam along the arrow direction. The light-guiding rod  12  is a solid light-permeable structure and has a reflective surface  121 . When the light-guiding rod  12  is configured on the light path of the LED unit  11 , the light beam emitted from the LED unit  11  will be reflected by the reflective surface  121  of the light-guiding rod  12  and then outputted. 
     Unfortunately, the optical property of the light-guiding rod  12  will trap the light of the LED unit  11  inside the light-guiding rod  12  and thus cause some energy loss. Thus, the emitted light can not be fully used. Although the reflective surface  121  can reflect the light beam to slightly increase the light output quantity, the energy loss in the light-guiding rod  12  can not be recovered so that the final light output quantity can not be sufficiently improved. 
     Besides, the light irradiation range of the LED unit  11  is smaller, so the indoor light brightness may be insufficient. In order to increase the light intensity of the LED unit  11  to reach the requirement for indoor illumination, the lighting efficiency will be sacrificed and thus worse than the convention fluorescent lamp (or higher power consumption than the fluorescent lamp). Moreover, in order to improve the issue of small light irradiation range, which causes the poor indoor light brightness, the amount of the installed lighting apparatuses must be increased. However, the additional lighting apparatuses will increase the hardware cost, maintaining cost, and energy cost. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, an objective of the present invention is to provide a transflective lighting apparatus so that the emitted light of the lighting apparatus has higher efficiency and larger lighting angle. 
     To achieve the above objective, the present invention discloses a lighting apparatus including a circuit board, a plurality of light-emitting diode (LED) units and an optical element. The optical element is transflective. The LED units and the optical element are disposed on the circuit board. The optical element has at least one reflective, surface so that lights emitted from the LED units to the optical element partially penetrate through and are partially reflected by the optical element. 
     In one embodiment of the invention, the optical element is made of a transparent material; otherwise, the optical element is made of an opaque material and has at least an opening. The opening allows the optical element to be transflective. 
     In one embodiment of the invention, the reflective surface comprises at least a planar surface, at least a curved surface, or their combination. The reflective surface is composed of one or more planar and/or curved surfaces. In practice, the reflective surface may have different combination aspects composed of, for example, a single planar surface, a single curved surface, multiple planar surfaces, multiple curved surfaces, one planar surface and one curved surface, one planar surface and multiple curved surfaces, one curved surface and multiple planar surfaces, or multiple planar surfaces and multiple curved surfaces. 
     In one embodiment of the invention, all or a part of the reflective surface is a smooth surface, a rough surface, or their combination. In practice, the reflective surface can be an entirely smooth surface, a partial smooth surface, an entirely rough surface, a partial rough surface, or a partial smooth and partial rough surface. 
     In one embodiment of the invention, the lighting apparatus further comprises a lamp base electrically connected to the circuit board. 
     In one embodiment of the invention, the lighting apparatus further comprises a lampshade connected to a periphery of the lamp base for covering the LED units and the optical element. The lampshade comprises a fluorescent material. In practice, the lampshade is doped with fluorescent powders for modulating the color of the light emitted from the LED units. 
     In one embodiment of the invention, the angle between a refracted light and a reflected light through the optical element is larger than 120°. 
     In one embodiment of the invention, the optical element is located on a geometrical center of the LED units. 
     In one embodiment of the invention, the LED units are correspondingly disposed adjacent to a periphery of the optical element along a protection direction. 
     In one embodiment of the invention, the LED units emit different color lights. 
     In one embodiment of the invention, the LED units are regularly or irregularly arranged. 
     In one embodiment of the invention, each of the LED units comprises at least a LED die or at least a LED package. 
     To achieve the above objective, the present invention also discloses a lighting apparatus, including a circuit board, a plurality of LED units, a lamp base, a lampshade and an optical element. The LED units are disposed on the circuit board. The amp base is electrically connected to the circuit board. The lampshade is connected to a periphery of the lamp base for covering the LED units. The optical element is transflective and is connected to the lampshade. The optical element has at least one reflective surface so that lights emitted from the LED units to the optical element partially penetrate through and are partially reflected by the optical element. 
     As mentioned above, the lighting apparatus of the invention includes an optical element, which has a reflective surface and is transflective. The optical element is disposed on the circuit board, so that the lights emitted from the LED units partially penetrate through and are partially reflected by the optical element. Accordingly, the overall lights emitted from the LED units can be more efficiently utilized, thereby reducing the light loss and increasing the light quantity of the lighting apparatus. The light transmission and reflection depend on some conditions such as the material, opening, surface shape, roughness of the reflective surface, and the positions of the optical element and the LED units, so the lighting apparatus of the invention can be properly designed to make the light reach the maximum angle after reflected by the optical element. This design can improve the issue of small light irradiation range and increase the indoor brightness, so that the total configured amount of the lighting apparatuses can be decreased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the subsequent detailed description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic diagram of a conventional lighting apparatus; 
         FIGS. 2A and 2B  are schematic diagrams showing the structure of the lighting apparatus of the invention; 
         FIGS. 3A and 3B  are schematic diagrams showing the optical element with an opening of the lighting apparatus of the invention; 
         FIGS. 4A to 4F  are schematic diagrams showing various optical elements of the lighting apparatus of the invention; 
         FIG. 5A  is a schematic diagram showing a circuit board of the lighting apparatus of the invention, wherein the circuit board is electrically connected to the lamp base; 
         FIG. 5B  is a schematic diagram showing a lampshade of the lighting apparatus of the invention, wherein the lampshade is connected to the lamp base; and 
         FIG. 6  is a schematic diagram showing another optical element of the lighting apparatus of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
       FIG. 2A  is a schematic diagram showing the structure of a lighting apparatus  2  of the invention. The lighting apparatus  2  includes a plurality of LED units  11 , which are disposed on the circuit board  21  and configured for emitting light. The LED unit  11  includes at least one LED die or at least one LED package. The lighting apparatus  2  also includes an optical element  22 , which is transflective and is disposed on the circuit board  21 . The optical element  22  has at least one reflective surface  221  so that tights emitted from the LED units  11  to the optical element  22  partially penetrate through and are partially reflected by the optical element  22 . The WI w “transflective” means that a part of the lights emitted from the LED units  11  to the optical element  22  can directly pass through the optical element  22  (refracted light), and the residual part thereof is reflected by the optical element  22  (reflected light). The angle θbetween the refracted light and the reflected light is larger than 120°. 
     The optical element  22  is made of a transparent material such as glass, acrylic, resin, plastic, or the likes. Alternatively, the optical element  22  may be made of an opaque material and include at least one opening for achieving the same transflective effect. The opaque material is, for example but not limited to, a metal material or a non-metal material with a reflective surface/layer. 
       FIGS. 3A and 3B  are schematic diagrams showing the optical element with an opening of the lighting apparatus of the invention. Herein, the optical elements  32  and  32   a  are made of opaque materials, and the light emitted from the LED units  11  can pass through the opening of the optical element  32  or  32   a.  The opening can he a trench (not shown) or a hole, such as a through hole  321  shown in  FIG. 3A  or a half hole  322  shown in  FIG. 3B . The term “half hole” is formed by drilling the optical element and remaining the material of the drilled part, wherein the remained material is partially connected to the edge of the hole. When the optical element  32  or  32   a  is configured with many openings, the sizes and shapes of the openings and the intervals between the openings can be the same or different. 
       FIGS. 4A to 4F  are schematic diagrams showing various optical elements of the lighting apparatus of the invention. The reflective surface of the optical element is composed of at least one planar surface, at least one curved surface, or their combinations. In the lighting apparatus  4   a  shown in  FIG. 4A , the reflective surface of the optical element  42   a  includes a plurality of planar surfaces. In the lighting apparatus  4   b  shown in  FIG. 4B , the reflective surface of the optical element  42   b  includes a plurality of curved surfaces. In the lighting apparatus  4   c  shown in  FIG. 4C , the reflective surface of the optical element  42   c  includes one planar surface and one curved surface, In the lighting apparatus  4   d  shown in  FIG. 4D , the reflective surface of the optical element  42   d  includes one planar surface and a plurality of curved surfaces. In the lighting apparatus  4   e  shown in  FIG. 4E , the reflective surface of the optical element  42   e  includes one curved surface and a plurality of planar surfaces. In the lighting apparatus  4   f  shown in  FIG. 4F , the reflective surface of the optical element  42   f  includes a plurality of planar surfaces and a plurality of curved surfaces. Those skilled in the art should know that the reflective surface can be carried out by any available way and not limited to the above aspects. 
     For example, the reflective surface may include entirely smooth surfaces, partially smooth surfaces, entirely rough surfaces, partially rough surfaces, or partially smooth and partially rough surfaces. 
       FIG. 5A  is a schematic diagram showing a circuit board  21  of the lighting apparatus  5  of the invention, wherein the circuit board  21  is electrically connected to a lamp base  51 . In this embodiment, the lighting apparatus  5  further includes a lamp base  51 , and a power source assembly is configured inside the lamp base  51  for providing power to the LED units  11  disposed on the circuit board  21 . 
       FIG. 5B  is a schematic diagram showing a lampshade  52  of the lighting apparatus  5   a  of the invention, wherein the lampshade  52  is connected to the lamp base  51 . In this embodiment, the lighting apparatus  5   a  further includes a lampshade  52  connected to the periphery of the lamp base  51 . The lampshade  52  covers the LED units  11  and the optical element  22  to prevent the undesired damage caused by dusts or external forces. The material of the lampshade  52  may include a fluorescent material for changing or modulating the color of the lights emitted from the LED units  11 . Alternatively, the LED units  11  can emit different color lights. 
       FIG. 6  is a schematic diagram showing another optical element of the lighting apparatus of the invention. Different from those of  FIG. 5B , the lighting apparatus shown in  FIG. 6  includes an optical element  62 , which is connected to the lampshade  52  instead of the circuit board  21 . 
     The LED units  11  are regularly arranged in, for example, annular configuration, concentric-circle configuration, array configuration, slant-array configuration, or the likes. Otherwise, the LED units  11  can be irregularly arranged in, for example, random configuration, scattered configuration, or the likes. In addition, the LED units  11  can be partially or totally arranged in high-low density on the circuit board  21  according to the requirement for light output intensity. For example, the area requiring higher light output intensity is corresponding to higher density of LED units  11  on the circuit board  21 ; otherwise, the area requiring lower light output intensity is corresponding to lower density of LED units  11  on the circuit board  21 . 
     Regardless of the arrangement of LED units  11 , as shown in  FIG. 2B , the optical element  22  is disposed at the geometric center of the LED units  11 . Besides, the LED units  11  are correspondingly disposed adjacent to a periphery of the optical element  22  along a protection direction of the optical element  22 . In more detailed, on the projection direction of the optical element  22 , the periphery of the optical element  22  passes through the LED units  11 . The positions of the LED units  11  are distributed within a certain range around the periphery of the optical element  22 . 
     In summary, the lighting apparatus of the invention includes an optical element, which has a reflective surface and is transflective. The optical element is disposed on the circuit hoard, so that the lights emitted from the LED units partially penetrate through and are partially reflected by the optical element. Accordingly, the overall lights emitted from the LED units can be more efficiently utilized, thereby reducing the light loss and increasing the light quantity of the lighting apparatus. The light transmission and reflection depend on some conditions such as the material, opening, surface shape, roughness of the reflective surface, and the positions of the optical element and the LED units, so the lighting apparatus of the invention can be properly designed to make the light reach the maximum angle after reflected by the optical element. This design can improve the issue of small light irradiation range and increase the indoor brightness, so that the total configured amount of the lighting apparatuses can be decreased. 
     Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the present invention.