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Remote Phosphor

What is Remote Phosphor? Let’s first look at the design of conventional white LEDS. These LEDs actually have a chip emitting deep blue or ultra-violet light. A dome encapsulating the chip is doped with several rare earth phosphors. The latter are excited by the blue light and emit colors at longer wavelengths. The mixture of the phosphors determine the color temperature of the quasi-white light and also the Color Rendering Index (CRI) wich is a measure how close the light comes to true sunlight.

As LEDs have become very powerful, a lot of light emerges from a very small package and can cause eye damage. Remedies include secondary optics and diffusers. Those devices will cause loss of light.

There is another approach. Enclose the blue LED with a larger structure where the color-conversion takes place in a plate, dome or globe with a large surface area. Hence the term Remote Phosphor.


The drawing to the left shows the conceptual design of a light using the remote phosphor technique.

The overall diameter of the device is about 2.5 inches where the light-emitting surface is about 2.25 inches in diameter.

There is more to this story. The heat sink needs to be cooled. We are employing a novel method of a blower that has no moving parts.

Each of the elements of the fixture will be discussed below.



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