Patent Grant
9239160
The disclosure relates to methods, systems, and apparatuses for light emitting diode lighting, and, more particularly, to methods, systems, and apparatuses for cooling light emitting diodes.
A light emitting diode (“LED”) is a semiconductor light source, which has a longer lifetime, faster switching, smaller physical size, greater durability and higher energy efficiency than current day lighting devices, e.g., fluorescent lights bulbs or incandescent light bulbs. When an LED is forward biased, electrons (negative charges) recombine with holes (positive charges), releasing energy in the form of photons. The energy difference between the electrons and holes of the LED produces photons of different wavelengths. Certain wavelengths provide for specific visible colors. Thus, the LED does not require color filters to produce any specific colors.
Generally, LEDs are solid state devices, and if operated at low currents and at low temperatures, are subject to limited device wear and tear. Lifetimes of LEDs are anywhere from around five to fifty times longer than fluorescent light bulbs and incandescent light bulbs. LEDs are also less susceptible to damage than fluorescent and incandescent light bulbs.
LEDs produce more light per watt than incandescent bulbs, and are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently. LEDs can very easily be dimmed continuously unlike fluorescent lamps which require a certain threshold voltage to maintain illumination.
LEDs have been found to have significant environmental benefits compared to other alternatives. For instance, a building's carbon footprint from lighting can be significantly reduced by exchanging all incandescent bulbs for LED light bulbs. LEDs are also non-toxic compared to fluorescent light bulbs, which contain traces of mercury.
Performance of LEDs is temperature dependent, and LED light output can actually increase at lower temperatures. LEDs do not generate as much heat as incandescent bulbs, but LEDs do produce internal heat which must be dissipated if the LED is to maintain good performance and low temperatures. Conversely, over-heating LEDs can lead to major device failure.
In order to combat overheating of LEDs, LED lights have incorporated heat sinks to dissipate heat generated by the LEDs. Heat sinks are widely available for LEDs, but any improvement in cooling can increase device operations and reliability. Some heat sinks are made by simply having a number of cooling fins connected to the LEDs. However, these designs are bulky, aesthetically unpleasing, and expensive to build LED light bulbs.
Therefore, it is desirable to develop new methods, systems, and apparatuses for cooling LED lighting (e.g., LED light bulbs, LED lamps, and other LED lighting apparatuses) to increase performance and maintain a long lifespan for the LEDs.
Briefly, the disclosure relates to a light emitting diode (“LED”) lighting apparatus, comprising: one or more strips, wherein each of the one or more strips has LEDs and a transparent backing; a base having vents, wherein the vents comprise a central vent and side vents and wherein the central vent and certain ones of the side vents are connected to allow for gas flow; and one or more glass tubes, wherein the one or more strips and the one or more glass tubes are coupled to the base, wherein the one or more glass tubes encapsulate the one or more strips, wherein the central vent is disposed adjacent to the one or more glass tubes, and wherein a heat transfer medium within selected ones of the one or more glass tubes flows out of the selected ones of the one or more glass tubes for cooling.
The foregoing and other aspects of the disclosure can be better understood from the following detailed description of the embodiments when taken in conjunction with the accompanying drawings.
a-3b illustrate side views of a base of an LED lighting apparatus having a central vent and side vents.
In the following detailed description of the embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration of specific embodiments in which the disclosure may be practiced.
When the LED strips 14 are activated, i.e., the LEDs are on, heat is generated. The generated heat is transferred to the glass tubes 12. The gas flow through vents 16 and 18 of the base 10 can be directed along the glass tubes 12 to cool the glass tubes 12. Thereby, the LED strips 14 can be cooled by using the glass tubes 12 to transfer the heat away from the LED strips 14. The vents 16 and 18 are bidirectional in that gas can flow either into the vent or out of the vent. The side vents 16 are located at the sides of the base 10 and away from the LED strips 14. The central vent 18 is located in between the LED strips 14. The gas near the side vents 16 are generally cooler than the gas near the central vent 18 since the LED strips 14 generate heat and are closer to the central vent 18. The central vent 18 can be connected to the side vents 16 such that the gas near the side vents 16 can be directed and expelled through the central vent 18 or gas near the central vent 18 can be directed and expelled through the side vents 16. Furthermore, a fan (not shown and an optional component) can be located in the base 10 along the gas flow to increase gas flow through the vents 16 and 18.
In an example, as the gas between the glass tubes 12 is heated up, cooler gas near the side vents 16 can travel through the base 10 and out through the central vent 18 to circulate out the heated gas and to cool the exterior walls of the glass tubes 12. Conversely, depending on the orientation of the LED lighting apparatus, the heated gas can travel through the central vent 18 and out to the side vents 16 to allow for cooler gas to circulate across the glass tubes 12.
In another example, certain ones of the vents 16 can be connected directly to the encapsulated portions of the glass tubes 12. In his manner, a heat transfer medium, e.g., gas, can circulate from outside the LED lighting apparatus to the encapsulated portions of the glass tubes 12. Also, the heat transfer medium within the encapsulated portions of the glass tubes 12 can be expelled out of the glass tubes with a cooler heat transfer medium being circulated into the glass tubes 12.
In yet another example, the heat transfer medium can be liquid. Here, certain ones of the glass tubes 12 can contain liquid to increase the heat transfer from the LEDs of the LED strips 14 to the glass tubes 12. Furthermore, a liquid cooling unit (not shown and an optional component) can be disposed in the base 10 to further cool the liquid within the glass tubes 12. The liquid within the encapsulated portions of the glass tubes 12 can be expelled out of the glass tubes to the liquid cooling unit to be cooled, and then the cooled liquid can be recirculated back into the glass tubes 12.
a-3b illustrate side views of a base of an LED lighting apparatus having a central vent and side vents.
a illustrates the base of the LED lighting apparatus positioned in an upward orientation. The LED lighting apparatus is illustrated without glass tubes and LED strips in order to emphasize gas flow through a base 30 of the LED lighting apparatus. However, the present disclosure is not limited by this figure since it is understood that any number of glass tubes and LED strips can be coupled to the base 30.
The base 30 can have vents 32 and 34 and a fan 36 to promote gas flow. Depending on the environmental conditions near the LED lighting apparatus (e.g., the direction of gravity, ambient temperature(s), and/or other environmental conditions) and the fan's blowing direction, heated gas can flow upwards with cooler gasses from the side vents 32 entering the base 30 and circulating to the central vent 34. This orientation can be referred to as an upward orientation of the LED lighting apparatus. The fan 36 can increase the gas flow through the vents 32 and 34 by pumping additional gas up through the central vent 34.
b illustrates the base of the LED lighting apparatus positioned in a downward orientation. In another example, the orientation of the LED lighting apparatus can be positioned such that the heated gas can circulate through the central vent 34 and out the side vents 32. This orientation can be referred to as a downward orientation. The fan 36 can also aid in the gas flow by pumping the heated gas from the central vent 34 to be expelled by the side vents 32.
The gas within the glass tube 40 can be circulated to the outside of the LED lighting apparatus via the vents 48 and 52. Cooler gas can be circulated from the outside area relative to the LED lighting apparatus to inside the glass tube 40 via the vents 46 and 50. In particular, the vents 52 and 48 are connected such that gas can flow into one vent and out the other vent. The vents 46 and 50 are also connected such that gas can flow into one vent and out the other vent. Furthermore, the vents 46-52 are bidirectional. Thus, the reverse gas flow for each pair of vents can also occur.
In one scenario, gas can flow into vent 46, and then into the glass tube 40 via the internal vent 50. The gas inside the glass tube 40 can flow out at the vent 48 via the vent 52. It is important to note that additional vents can be used based on the present disclosure. Therefore, the present illustration is not meant to limit the present disclosure to two vents for each of the glass tubes. In fact, it is understood by a person having ordinary skill in the art that additional vents can be added to increase gas flow to and out of the glass tube. The LED lighting apparatus using gas cooling can also comprise other methods for cooling the LEDs, including those described in the present disclosure.
The vents 70-72 are bidirectional. Thus, the reverse liquid flow for the pair of vents can also occur. For instance, liquid can flow out the vent 72 to the liquid cooling unit 74 to be cooled. The cooled liquid is circulated back into the glass tube 40 via the vent 70. It is important to note that additional vents can be used based on the present disclosure. Therefore, the present illustration is not meant to limit the present disclosure to two vents for each of the glass tubes. In fact, it is understood by a person having ordinary skill in the art that additional vents can be added to increase liquid flow to and out of the glass tube. The LED lighting apparatus using liquid cooling can also comprise other methods for cooling the LEDs, including those described in the present disclosure.
The liquid can be pigmented to allow for a colored indicator to indicate the temperature of the LEDs of the LED lighting apparatus. For instance, the liquid can be colored various shades of yellow to indicate a relative temperature for the LEDs of the LED lighting apparatus.
The liquid can also be pigmented to change the emitted color of the LED lighting apparatus to approximate one or more predefined colors. For instance, if the LED strip emits a blue-ish light, the liquid can have a yellowish pigment to give a warmer yellow color to the emitted light. Furthermore, the emitted light can be strobed between various colors by altering the pigments in the liquid.
In various embodiments of the present invention, various combinations of cooling methods can be used together in the same lighting apparatus. Referring to
While the disclosure has been described with reference to certain embodiments, it is to be understood that the disclosure is not limited to such embodiments. Rather, the disclosure should be understood and construed in its broadest meaning, as reflected by the following claims. Thus, these claims are to be understood as incorporating not only the apparatuses, methods, and systems described herein, but all those other and further alterations and modifications as would be apparent to those of ordinary skilled in the art.
| Number | Name | Date | Kind |
|---|---|---|---|
| 20050128752 | Ewington et al. | Jun 2005 | A1 |
| 20110156584 | Kim | Jun 2011 | A1 |
| 20120300475 | Kim | Nov 2012 | A1 |
