Dining “Chandelier” with Multi-Color LEDs
Design of ceiling-mounted light fixture using tri-color LEDs.
January 2006 by Ron Jeuch
The technology of high-power light emitting diodes (LED) is advancing rapidly. Removing heat from the LED junction is a major issue for high power LEDs. Obtaining light that is pleasant to the eyes is also a problem.
Humans have lived for many decades with what we call warm light sources (oil lamps, candles and tungsten incandescent bulbs). Earlier projects have addressed this topic by using warm-white LEDs or combining multi-colored LEDs.
Lamina Ceramics (New Jersey) has introduced several new LEDs with an efficient heat transfer between the LED junction and the underlying carrier. This allow the mounting of several LED chips of a single color or multiple colors in one cavity.
This project deals with a special type which has two LED chips each for the colors red, green and blue on a single substrate, producing a light output three times higher that was available before.
The photo shows the finished fixture mounted above a round table in our breakfast area of the kitchen.
The large octagonal center section contains the electronics. The black parts at the end of each arm are aluminum heat sinks and the short tubes serve as baffles hiding the high-intensity surface of the collimating lens from the eyes.