1. Field of the Invention
The present invention relates to a light emitting diode (LED) lamp, and more particularly to an LED lamp having a heat sink for improving heat dissipation efficiency of the LED lamp.
2. Description of Related Art
The technology of LED has been rapidly developed in recent years from indicators to illumination applications. With the features of long-term reliability, environment friendliness and low power consumption, the LED is viewed as a promising alternative for future lighting products. Nevertheless, the rate of heat generation increases with the illumination intensity. This issue has become a challenge for engineers to design the LED illumination, i.e. the LED lamp.
What is needed, therefore, is an LED lamp which has greater heat-transfer and heat dissipation capabilities, whereby the LED lamp can operate normally for a sufficiently long period of time.
An LED lamp for a lighting purpose includes a first heat sink, a lamp base, a plurality of LED modules, an envelope and a second heat sink. The first heat sink includes a cylinder at a centre thereof and a plurality of fins surrounding the cylinder. The lamp base is secured to a bottom portion of the first heat sink, adapted for mounting the LED lamp to a lamp socket. The LED modules are mounted on the fins of the first heat sink. Each of the LED modules comprises a printed circuit board and a plurality of LEDs mounted on the printed circuit board. The envelope is mounted between the lamp base and the second heat sink and encloses the first heat sink and the LED modules therein. The second heat sink has a disc-like configuration and extends through the envelope and connects with a top portion of the first heat sink. Heat generated by the LEDs are first absorbed by the fins, and then transferred to the cylinder of the first heat sink and the second heat sink to be dissipated into surrounding atmosphere.
Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
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A plurality of pairs of outer fins 251 are formed on two opposite lateral sides of each of the conducting arms 25. Each pair of the outer fins 251 extend respectively and perpendicularly from the two opposite lateral sides of each corresponding conducting arm 25, and are symmetrical to each other relative to the corresponding conducting arm 25. The outer fins 251 at a lateral side of each of the conducting arms 25 are increasing in length along a direction from the cylinder 21 to a distal end of the corresponding conducting arm 25. The distal end of the conducting arm 25 terminates at an inner face of an outermost one of the outer fins 251. An outer face of each outermost outer fin 251 is flat and used for thermally contacting with the LED module 30. Four mounting holes 253 are defined in outmost ends of top portions of four of the conducting arms 25, wherein the through holes 253 are centrosymmetric relative to the central axis of the elongated cylinder 21. Four elongated ridges 23 extend outwardly from the out sidewall of the cylinder 21 of the first heat sink 20 and are evenly formed around the cylinder 21. Each ridge 23 is located between two adjacent conducting arms 25. Each of the ridges 23 defines a mounting hole 231 therein aligned with a corresponding screw hole 1612 of the mounting portion 161 of the lamp base 10. The upper portions of the fasteners extend through the mounting holes 231 of the ridges 23. In this state, a bottom portion of the first heat sink 20 is received in the sleeve 18 of the lamp base 10.
Referring to
The envelope 50 has a frustum-like body (not labeled) and a disc-like cover 51. The body has top and bottom openings (not shown) defined therethrough. The cover 51 has a central hole 512 defined therein. The cover 51 forms an annular protrusion 514 around the central hole 512 thereof. An inner periphery of the protrusion 514 defines four through holes 516 therein, which are aligned with the corresponding mounting holes 253 of the first heat sink 20. The cover 51 further defines three screw holes 518 aligned with the through holes of the tabs 181 and the screw holes 1832 of the protrusions 183 of the sleeve 18 of the lamp base 10. Screws (not shown) extend through the through holes 516 of the cover 51 and engage in the mounting holes 253 of the first heat sink 20 to fix the cover 51 on the heat sink 20. The top opening and the bottom opening of the body of the envelope 50 engage with the cover 51 and the top portion of the lamp holder 12 of the lamp base 10 respectively. Therefore, the lamp base 10 and the envelope 50 together define an enclosed housing (not labeled) accommodating the LED modules 30 and the first heat sink 20 therein, whereby the LED modules 30 can have a sufficient protection for preventing from a damage caused by an unexpected force acting on the LED lamp.
Each reflector 40 has an disc-like configuration, and an opening (not labeled) is defined at a center therein. An inner edge of the reflector 40 equidistantly forms three mounting tabs 41. The reflectors 40 are mounted around the printed circuit boards 32. The reflectors 40 are evenly spaced disposed at the periphery of the first heat sink 20 by a plurality of collars 70 aligned with the tabs 41 of the reflectors 40. The collars 70 are located between the conducting arms 25 of the first heat sink 20. A plurality of elongated poles 80 extends through the collars 70, the corresponding tabs 41 of the reflectors 40, and the tabs 181 of the sleeve 18; simultaneously bottom ends of the elongated poles 80 threadedly engage in the corresponding screw holes 1832 of the protrusions 183 of the sleeve 18 and top ends of the elongated poles 80 engage in the screw holes 518. Thus, the reflectors 40 are secured to the periphery of the first heat sink 20. The reflectors 40 improve the illumination of the LED lamp by redirect light rays generated by the LEDs 34 into a more consistently outward and downward direction.
The second heat sink 60 has a disc-like configuration and is made of high heat conductive metal, such as aluminum. The heat sink 60 comprises a base 61 (shown in
When the LEDs 34 emit light, heat generated by the LEDs 34 is conducted to the first heat sink 20, then rapidly transfers to the base 61 of the second heat sink 60, and finally dispersed into ambient cool air via the first and second fins 65, 67 mounted on the top face of the base 61 of the second heat sink 60. Therefore, temperature of the enclosed housing defined by the lamp base 10 and the envelope 50 is decreased. Thus it can be seen that the LED lamp has an improved heat dissipating configuration for preventing the LEDs 34 from overheating.
It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
Number | Date | Country | Kind |
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200710123993.1 | Oct 2007 | CN | national |