Patent Publication Number: US-8529095-B2

Title: Bulb-shaped LED lamp and compact LED lamp

Description:
TECHNICAL FIELD 
     The present invention relates to a bulb-shaped LED lamp and a compact LED lamp where light-emitting diodes (LEDs) are used as a light source. 
     BACKGROUND ART 
     In order to make luminance of light wavelength-converted by a wave-conversion cover approximately even and achieve a long operating life of fluorescence substance and light-emitting diode devices, there has been proposed a LED bulb provided with an LED light-emitting portion having a plurality of light-emitting diode devices for emitting near-ultraviolet light or blue light, which are arranged in a plane manner, a flat face portion disposed at a position spaced from a face on which the light-emitting diode devices are arranged by a predetermined distance so as to face the light-emitting diode devices, and a wavelength-converting cover provided on its flat face portion with fluorescence substance for wavelength-converting light emitted from the light-emitting diode devices (for example, see Patent Reference 1).
     Patent Reference 1: JP-A-2006-156187   

     DISCLOSURE OF THE INVENTION 
     Problem to be Solved by the Invention 
     However, the LED lamp proposed above has the following problems. 
     Since a large amount of light emitted from the LED light-emitting portion of the LED bulb leaks from a glass globe laterally, it is impossible to take out light in a front direction efficiently. 
     The present invention has been made to solve the abovementioned problems and an object thereof is to provide a bulb-shaped LED lamp which improves brightness and can obtain brightness corresponding to a filament bulb of 40 watts to 60 watts and a compact LED lamp. 
     Means for Solving the Problem 
     A bulb-shaped LED lamp according to the present invention comprises a plurality of high-intensity LED modules where a high-intensity LED is attached on an LED fixing base plate; a heat sink where the high-intensity LED modules are attached on one end face in an axial direction thereof along a circumferential direction, for performing radiation of the high-intensity LED modules; a reflector which is provided so as to surround the plurality of high-intensity LED modules, for guiding light from the high-intensity LED modules forward; an electronic circuit for driving which drives the high-intensity LED modules; a housing which houses the heat sink, the electronic circuit for driving, a portion of the reflector therein; and a globe which configures an outer shell together with the housing. 
     The bulb-shaped LED lamp according to the present invention has a configuration that a diffusion sheet is used as the reflector. 
     A bulb-shaped LED lamp according to the present invention comprises a plurality of high-intensity LED modules where a high-intensity LED is attached on an LED fixing base plate, each being provided around a high-intensity LED with a reflector for guiding light forward; a heat sink on which the high-intensity LED modules are attached on an end face in an axial direction thereof along a circumferential direction, for performing radiation of the high-intensity LED modules; an electronic circuit for driving which drives the high-intensity LED modules; a housing which houses the heat sink and the electronic circuit for driving; and a glass globe which configures an outer shell together with the housing. 
     A compact LED lamp according to the present invention comprises a plurality of high-intensity LED modules where a high-intensity LED is attached on an LED fixing base plate; a heat sink where the high-intensity LED modules are attached on an end face in an axial direction thereof along a circumferential direction, for performing radiation of the high-intensity LED modules; a reflector which is provided so as to surround the plurality of high-intensity LED modules, for guiding light from the high-intensity LED modules forward; a resin light-guiding blade member having the same number of blades as the number of high-intensity LED modules, where the blades are provided radially in a diametrical direction at approximately equal intervals, the blades have predetermined heights in the axial direction, and the respective blades are fixed on the high-intensity LED modules; an electronic circuit for driving which drives the high-intensity LED modules; and a housing which-houses the heat sink, the electronic circuit for driving, a portion of the reflector therein. 
     Effect of the Invention 
     With the abovementioned configuration, the bulb-shaped LED lamp according to the present invention can achieve such an effect that brightness is improved and brightness corresponding to a filament bulb of 40 watts to 60 watts can be obtained according to improvement of luminance of the high-intensity LEDs. 
     In the compact LED lamp according to the present invention, light from the high-intensity LED modules can be taken out laterally and forward efficiently by the resin light-guiding blade member having the same number of blades as the number of the high-intensity LED modules. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a first embodiment and a front view of a bulb-shaped LED lamp  1 . 
         FIG. 2  shows the first embodiment and a sectional view taken along line A-A in  FIG. 1 . 
         FIG. 3  shows a second embodiment and a front view of a compact LED lamp  10 . 
         FIG. 4  shows the second embodiment and a plan view of the compact LED  10  lamp viewed from the front thereof. 
         FIG. 5  shows a third embodiment and a plan view of a bulb-shaped LED lamp  1 . 
         FIG. 6  shows the third embodiment and a sectional view taken along line B-B in  FIG. 5 . 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS 
       1 : bulb-shaped LED lamp,  2 : high-intensity LED module,  2   a : high-intensity LED,  2   b : LED fixing base plate,  2   c : reflecting plate,  4 : reflector,  5 : heat sink,  6 : electronic circuit for driving,  7 : housing,  8 : globe,  9 : E26 base,  10 : compact LED lamp,  11 : resin light-guiding blade member,  11   a : blade 
     BEST MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
       FIG. 1  and  FIG. 2  show a first embodiment.  FIG. 1  shows a front view of a bulb-shaped LED lamp  1  and  FIG. 2  shows a sectional view taken along line A-A in  FIG. 1 . 
     As shown in  FIG. 1  and  FIG. 2 , a light source of the bulb-shaped LED lamp  1  is a high-intensity LED module  2  where a high-intensity LED  2   a  is attached on an LED fixing base plate  2   b . Six high-intensity LED modules  2  are used here. Brightness of the high-intensity LED  2   a  has 20 lm (lumen) per one piece at present, and the brightness reaches only 120 lm even when six high-intensity LEDs are used, but it is expected that luminance of the high-intensity LED  2   a  is rapidly raised in the near future. For example, when the brightness of the high-intensity LED  2   a  reaches a value corresponding to 100 lm per one piece, illuminance corresponding to a filament bulb of 40 to 60 watts is obtained under such a condition that a distance between a subject and the bulb-shaped LED lamp  1  is in a range of 1 m to 2 m and a distance in circumferential direction is about 2 m by the bulb-shaped LED lamp  1  of a configuration in  FIG. 1  and  FIG. 2 . 
     Six high-intensity LED modules  2  are arranged and fixed on an end face of a heat sink  5  in an axial direction thereof along a circumferential direction. LED fixing base plates  2   b  are fixed on the heat sink  5  by adhesive or the like. The LED fixing base plate  2   b  is made from metal, polyimide resin, or the like. The heat sink  5  is a radiator plate made from, for example, aluminum, and heat generated from the high-intensity LED module  2  is transmitted and radiated efficiently. 
     A housing  7  is provided so as to surround the heat sink  5 . The housing  7  is made from PBT (polybutylene terephthalate) resin or such metal as aluminum. The housing  7  is provided therein with not only the heat sink  5  but also an electronic circuit for driving  6  that adjusts power taken in from an external power source to current/voltage for lighting each high-intensity LED  2   a  to supply the same to each high-intensity LED  2   a . Since the electronic circuit for driving  6  is a known one, explanation thereof is omitted. 
     The respective high-intensity LED modules  2  are surrounded by a reflector  4  optimized for efficiently taking out light from each high-intensity LED  2   a  forward. The reflector  4  is made of, for example, a diffusion sheet made from polycarbonate (PC), molded resin, or metal such as stainless steel. Lateral leakage of light from the high-intensity LEDs  2   a  is suppressed by the reflector  4 , so that light can be efficiently taken out forward. 
     A globe  8  is attached to the outside of the reflector  4 , and it configures an outer shell of a bulb-shaped LED lamp together with the housing  7 . Material of the globe  8  is resin, glass, or the like. The housing  7  is attached with an E26 base. An E17 base may be used instead of the E26 base. 
     When the housing  7  is made from resin, radiation from resin surface is insufficient, so that thermally-conductive silicon rubber is filled in the housing  7 , thereby coupling the heat sink  5  and the E26 base  9  thermally. 
     As described above, since the bulb-shaped LED lamp  1  according to the present embodiment uses the high-intensity LED modules  2 , where light can be taken out forward efficiently by the reflector  4  suppressing lateral leakage of light from the high-intensity LEDs  2   a , it is expected that, when luminance of a high-intensity LED 2   a  is raised in the future, illuminance corresponding to a filament bulb of 40 to 60 watts can be obtained under such a condition that a distance between a subject and the bulb-shaped LED lamp  1  is in a range of 1 m to 2 m and a distance in a circumferential direction is about 2 m. 
     Second Embodiment 
       FIG. 3  and  FIG. 4  show a second embodiment.  FIG. 3  shows a front view of a compact LED lamp  10  and  FIG. 4  shows a plan view of the compact LED lamp  10  viewed from the front thereof. 
     The compact LED lamp  10  is different from the bulb-shaped LED lamp  1  in  FIG. 1  in that the former does not have the globe  8  and it is provided with a resin light-guiding blade member  11 . The other configuration of the second embodiment is the same as that of the first embodiment. 
     The resin light-guiding blade member  11  has six blades  11   a  as shown in  FIG. 4 , where the blades  11   a  are provided radially in a diametrical direction at almost equal intervals. The blades  11   a  are set to predetermined heights in an axial direction (a height direction). Each blade  11   a  is bonded and fixed on the high-intensity LED module  2 . Light from the high-intensity LED modules  2  is guided efficiently by the resin light-guiding blade member  11  so that light can be taken out in a lateral direction (a diametrical direction) and in a forward direction. The resin light-guiding blade member  11  serves to diffuse light from the high-intensity LED modules  2  properly and serves to guide the light. 
     As described above, the compact LED lamp  10  according to the present embodiment can take out light from the high-intensity LED modules  2  in a lateral direction and a forward direction by the resin light-guiding blade member  11  having the same number of blades as the number of high-intensity LED modules  2 . 
     Third Embodiment 
       FIG. 5  and  FIG. 6  show a third embodiment.  FIG. 5  shows a plan view of a bulb-shaped LED lamp  1  and  FIG. 6  shows a sectional view taken along line B-B in  FIG. 5 . 
     In the first embodiment, the reflector  4  is provided so as to surround all of the high-intensity LED modules  2 , but reflecting plates  2   c  may be provided for individual high-intensity LED modules  2  instead of the reflector  4 . 
     As shown in  FIG. 5 , six high-intensity LED modules  2  each have a horn-shaped reflecting plate  2   c  for guiding light forward around the high-intensity LED  2   a . Since each high-intensity LED module  2  has the reflecting plate  2   c  for guiding light forward, the reflector  4  may be removed. 
     As shown in  FIG. 6 , in the high-intensity LED module  2 , the high-intensity LED  2   a  is provided on the LED fixing base plate  2   b  and the horn-shaped reflecting plate  2   c  is provided around the high-intensity LED  2   a . The LED fixing base plate  2   b  is bonded and fixed to the heat sink  5  by, for example, a double-faced adhesive tape. 
     As described above, in the bulb-shaped LED lamp  1  according to the present embodiment, the horn-shaped reflecting plates  2   c  for guiding light forward are provided around the high-intensity LEDs  2   a  of the individual high-intensity LED modules  2 , thereby the reflector  4  used in the first embodiment can be removed. 
     However, both the horn-shaped reflecting plates  2   c  for guiding light forward provided around the high-intensity LEDs  2   a  of the individual high-intensity LED modules  2  and the reflector  4  surrounding all of the high-intensity LED modules  2  may be used.