Patent Application
20120001530
1. Technical Field
The present disclosure relates to an LED lamp, and particularly to an LED lamp having a heat sink and a shell enclosing the heat sink for heat dissipation.
2. Description of Related Art
The technology of light emitting diode (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.
A related LED lamp includes a heat sink and a plurality of LED modules including LEDs, attached to an outer surface of the heat sink to enable dissipation of heat generated by the LEDs. In order to provide a high brightness, a reflector is mounted on the LED lamp to cover the heat sink, whereby light generated by the LEDs is repeatedly reflected by the reflector downwardly. However, ambient air around the heat sink is heated to flow upwardly, and then accumulates at a top of the reflector, making dissipation of the heat become problematic.
What is needed, 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.
Many aspects of the disclosure 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The heat sink 121 comprises a heat conducting body (not labeled), and a plurality of radial partition fins 1210 extending from an outer surface of the body. The radial partition fins 1210 extend along a direction from top to bottom. Two neighboring fins 1210 are spaced apart from one another with a channel therebetween. The LED module 120 comprises a plurality of LEDs (not labeled) installed at the bottom of the heat conducting body. A hemispherical, transparent cover 125 is engaged with the bottom of the heat sink 121 and covers the LED module 120. The transparent cover 125 is so dimensioned and positioned that bottom intakes of the channels between the fins 1210 are exposed downward to the surrounding air, without being blocked by the cover 125. Thus, air can easily flow upwardly along the cover 125 into the channels between the fins via the bottom intakes thereof.
The shell 16 is inverted frustum-shaped and comprises a top plate 161, a bottom plate 163 and a lateral wall 162 interconnecting with the top plate 161 and the bottom plate 163. The lamp holder 14 is mounted at the top plate 161 for connecting the connector 124 of the LED bulb 12. The lateral wall 162 is around the LED bulb 12 and has an angled inner surface 164 defined at an acute angle with respect to the bottom plate 163. The lateral wall 162 can be made of metal material which can reflect light. The bottom plate 163 is transparent. A part of light generated by the LED module 120 radiates downwardly directly through the transparent bottom plate 163. Another part of the light generated by the LED module 120 is reflected by the inner surface 164 of the lateral wall 162 to radiate downwardly through the transparent bottom plate 163. The lateral wall 162 defines a plurality of apertures 160 at a top portion thereof near a top of the heat sink 121; in other words, the apertures 160 is near outlets of the channels of the heat sink 121. The bottom plate 163 defines a plurality of holes 1630 near an edge thereof. The holes 1630 corresponds to the channels defined between the fins 1210.
According to the present disclosure, heat produced by the LED module 120 can be quickly transferred to the heat sink 121 via a thermal connection between the LED module 120 and the heat conducting body. The heat is transferred to the fins 1210, and is then dissipated away to ambient air via the fins 1210. Air in the channels defined between the fins 1210 is heated. The channels each function as a chimney for guiding the heated air to flow upwardly and outwardly to the apertures 160 of the lateral wall 162. The heated air is replaced by outside cooler air flowing from the holes 1630 of the bottom plate 163 into the shell 16 and toward the channels. By the provision of the channels in flow communication with the lower holes 1630 and the upper apertures 160, a natural air convection through the channels between the fins 1210 can be established, whereby the heat dissipation efficiency of the heat sink 121 can be improved. Thus, the heat produced by the LEDs can be removed by the heat sink 121 very quickly, thereby enabling the LED module 120 to work within a required temperature range.
Alternatively, the holes 1630 can be defined at a bottom portion of the lateral wall 162. The connector 124 can be designed to insert in the holder 14 to electrically connect the holder 14. The connector 124 of the LED bulb 12 can be standard component and available in the market, such as E26, E27, GU10, PAR30 or MR16. Furthermore, when the LED lamp 10 is used in an inverted position, the heated air in the channels among the fins 1210 flows upwardly and outwardly to the holes 1630 of the lateral walls 160, and replaced by outside cooler air flowing through the apertures 1630 of the bottom plate 163 into the shell 16.
Referring to
Different from the LED lamp 10 of the first embodiment, the LED module 220 and the cover 225 of the LED lamp 20 extend through the bottom plate 263 of the shell 26. The heat sink 221 is received in the shell 26. The bottom plate 263 of the shell 26 is installed between the heat sink 221 and the LED module 220. In other words, the shell 26 has a height less than that of the whole LED bulb 22. Heat produced by the LED module 220 can be quickly transferred to the fins 2210. The air in the channels defined between the fins 2210 is heated to flow out of the apertures 260 and replaced by cooler air flowing into the shell 26 from the holes 2630. Since the shell 26 has a height less than that of the whole LED bulb 22, air flowing through the shell 26 from bottom to top thereof is more quick than air flowing through the shell 16 of the first embodiment.
It is to be understood, however, that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 99121362 | Jun 2010 | TW | national |
