[opendtv] Re: LEDs shine as replacement for lightbulb

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 16 Nov 2007 17:19:24 -0500

Nope. In a CFL it is gaseous mercury electrons that get excited and emit UV photons. The phosphors glow in the visible spectrum when stimulated by the UV photons.


In a white LED, the it is the PN junction that emits UV photons, and stimulate the phosphors. There is no mercury in white LEDs.

John


----- Original Message ----- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>

John, you're strictly right, but I believe the mercury and the phosphors
work together, to convert UV into visible light.

http://www.epa.gov/mercury/consumer.htm

"Fluorescent Light Bulbs

"Mercury is used in the long fluorescent, compact fluorescent, and
high-intensity discharge (HID) lamps. Visible light is produced when the
mercury in the lamp is electrically energized."

These white LEDs work the same way. Thay too produce mostly UV, and need
to have it converted to white light. My guess is, they will also have to
use mercury, as all fluorescents have always done.

Bert




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