Patent Publication Number: US-2011051457-A1

Title: Ceiling mount led lamp

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a lamp, and more particularly, to an LED lamp adapted to be mounted on a ceiling. 
     2. The Prior Arts 
     Currently, luminaries mounted on ceilings are often used in home or offices. Such luminaries typically include chandeliers and ceiling mount fluorescent lamps. Generally, a typical chandelier often occupies a large space. When such a chandelier is provided in a home with a 2.7 m floor height, the space may be looked crowd and discordant. As to office used lamps, in most circumstances, ceiling mount fluorescent lamps are selected. A typical ceiling mount fluorescent lamp adapted for office use is a fluorescent lamp tube secured in a frame. Specifically, the frame is a flat metal-made π-shaped structure. The fluorescent lamp tube is secured inside the space defined in the frame, and a rectifier is secured on a backside of the frame or inside the space of the frame. Both of the foregoing luminaries disadvantageously consume much energy, and do not satisfy the demand of environmental protection. 
     LED lamps have the advantage of power saving. However, LED lamps are not yet applied in the field of ceiling mount lamps. As such, it is desired to develop a ceiling mount LED lamp for satisfying the demand of environmental protection. 
     SUMMARY OF THE INVENTION 
     Accordingly, a primary objective of the present invention is to provide a ceiling mount LED lamp. 
     The present invention provides a ceiling mount LED lamp. The ceiling mount LED lamp includes a securing unit, and a lighting unit. 
     The securing unit includes a frame body, a back plate, a top plate, and a plurality of holding strips. The back plate is positioned at an opposite side of the frame body. The top plate is positioned on the back plate. The holding strips are provided at periphery inner sides of the securing unit. The holding strips have a U-shaped cross-section. The U-shaped cross-section of the holding strips defines receiving recesses of the holding strips. 
     The lighting unit is positioned between the frame body and the back plate of the securing unit. The lighting unit includes a reflective sheet, at least one circuit board, a plurality of LED units, a light guide plate, and a diffusion sheet. 
     The reflective sheet is disposed on the top plate of the securing unit. The at least one circuit board is provided at at least one lateral side of the reflective sheet. The LED units are distributed on the circuit board. The light guide plate is disposed on the reflective sheet for transmitting light emitted from the LED units and reflected by the reflective sheet. The diffusion sheet is disposed on the light guide plate, for diffusing the light outputted from the light guide plate. 
     According to an aspect of the embodiment, the lighting unit includes two or more circuit boards provided at two or more lateral sides of the reflective sheet respectively. In this case, the light guide plate is positioned between the two or more circuit boards. 
     Edges of the reflective sheet, the circuit board, the light guide plate and the diffusion sheet of the lighting unit are received and held in the receiving recesses of the holding strips of the securing unit, such that the reflective sheet, the circuit board, the light guide plate, and the diffusion sheet of the lighting unit are secured between the frame body and the back plate of the securing unit. The securing unit further includes a power adaptor coupled to the circuit board. 
     In accordance with the foregoing embodiment, the present invention provides a ceiling mount LED lamp. The ceiling mount LED lamp has a simple structure and can be conveniently assembled and disassembled. Further, it is cheap and suitable for mass production. Furthermore, the present invention advantageously applies LED units in ceiling mount lamps to achieve a higher brightness and better energy efficiency. Comparing with the conventional light sources, the ceiling mount LED lamp of the present invention saves about 60% of power, and further has the advantages of no UV and IR radiation, no flickering, no stroboflash, and quick start. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following detailed description of preferred embodiments thereof, with reference to the attached drawings, in which: 
         FIG. 1  is a perspective view of a ceiling mount LED lamp according to an embodiment of the present invention; 
         FIG. 2  is an exploded view of the ceiling mount LED lamp according to an embodiment of the present invention; and 
         FIG. 3  is a cross-sectional view of the ceiling mount LED lamp according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawing illustrates embodiments of the invention and, together with the description, serves to explain the principles of the invention. 
       FIG. 1  is a perspective view of a ceiling mount LED lamp according to an embodiment of the present invention.  FIG. 2  is an exploded view of the ceiling mount LED lamp according to an embodiment of the present invention.  FIG. 3  is a cross-sectional view of the ceiling mount LED lamp according to an embodiment of the present invention. 
     Referring to  FIGS. 1 through 3 , the ceiling mount LED lamp includes a securing unit  1 , and a lighting unit  2 . 
     The securing unit  1  includes a frame body  11 , a back plate  13 , a top plate  14 , and a plurality of holding strips  12 . The back plate  13  is positioned at an opposite side of the frame body  11 . The top plate  14  is positioned on the back plate  13 . The holding strips  12  are provided at periphery inner sides of the securing unit  1 . The holding strips  12  have a U-shaped cross-section. The U-shaped cross-section of holding strips  12  defines receiving recesses of the holding strips  12 . 
     The lighting unit  2  is positioned between the frame body  11  and the back plate  13  of the securing unit  2 . The lighting unit  2  includes a reflective sheet  22 , at least one circuit board  211 , a plurality of LED units  21 , a light guide plate  23 , and a diffusion sheet  24 . 
     The reflective sheet  22  is disposed on the top plate  14  of the securing unit  1 . The at least one circuit board  211  is provided at at least one lateral side of the reflective sheet  22 . The LED units  21  are distributed on the circuit board  211 . The light guide plate  23  is disposed on the reflective sheet  22  for transmitting light emitted from the LED units  21  and reflected by the reflective sheet  22 . The diffusion sheet  24  is disposed on the light guide plate  23 , for further diffusing and softening the light outputted from the light guide plate  23 . 
     According to an aspect of the embodiment, the lighting unit  2  includes two or more circuit boards  211  provided at two or more lateral sides of the reflective sheet  22  respectively. In this case, the light guide plate  23  is positioned between the two or more circuit boards  211 . 
     Edges of the reflective sheet  22 , the circuit board(s)  211 , the light guide plate  23 , and the diffusion sheet  24  of the lighting unit  2  are received and held in the receiving recesses of the holding strips  12  of the securing unit  1 , such that the reflective sheet  22 , the circuit board(s)  211 , the light guide plate  23 , and the diffusion sheet  24  of the lighting unit  2  are secured between the frame body  11  and the back plate  13  of the securing unit  1 . The securing unit  1  further includes a power adaptor  3  electrically coupled to the circuit board(s)  211 . 
     The LED units  21  are disposed on one side of the circuit board  211  of the light unit  2 , and at least one heat dissipating strip  212  is provided on an opposite side of the circuit board  211  for facilitating to dissipate heat generated by the circuit board  211  and the LED units  21 . 
     Each circuit board  211  includes two electrodes configured at an end thereof. Wires are provided for coupling the two electrodes of the circuit board  211  with two output terminals of a power adapter  3 . The power adapter  3  is coupled with an external power source (not shown in the drawings). Preferably, each of the circuit boards is further provided with a reflective strip (not shown in the drawings) for reflecting any light transmitted from the light guide plate  23  thereto. 
     In accordance with the embodiment of the present invention, the LED units  21  consume direct current (DC) power, and correspondingly the power adapter  3  is adapted for converting an alternating current (AC) power into a DC power in accordance with the demand of the LED units  21 . 
     The circuit board  211  contains a printed circuit. The printed circuit may be serially coupled, parallel coupled, or serial-parallel hybrid coupled in accordance with demand of the practical power, current and voltage. 
     The frame body  11  is made of a metal plate. The reflective sheet  22  is made of polyethylene terephthalate (PET) or polycarbonate (PC) material, and is adapted for reflecting and scattering the light transmitted from the LED units  21  and light guide plate  23 . The diffusion sheet  24  is preferably made by coating a mixture of a transparent resin and a light diffusing material on a PET substrate, or rolling with a roller on a PC substrate to form an uneven and coarse surface. The light guide plate  23  is a polymethyl methacrylate (PMMA) plate, i.e., a particularly treated organic glass. In addition, a heating dry ink or a UV ink (diffusion and reflection characterized SiO2/TiO2) is printed by a screen printing process to form a dot array on a reflective side of the light guide plate  23 . The provision of the dot array destroys the total reflection of the light guide plate  23 , and diffuses the light inputted therein, thus achieving a diffuse reflection and outputting a uniformed light from an outputting surface of the light guide plate  23 . The dots of the dot array are preferably distributed in a manner of varying from a smaller density to a greater density and from a smaller size to a greater size. 
     The light guide plate  23  is adapted for transmitting while repetitively reflecting and deflecting the light emitted from the LED units  21 , such that the light guide plate  23  serves as a flat light source. The diffusion sheet  6  shelters the dots and uniforms the light, and therefore, the ceiling mount LED lamp is adapted to emit a uniformed and softened light. 
     In accordance with the foregoing embodiment, the present invention provides a ceiling mount LED lamp. The ceiling mount LED lamp has a simple structure and can be conveniently assembled and disassembled. Further, it is cheap and suitable for mass production. 
     Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.