On 17 May, 08:39, "Man at B&Q" wrote:
On May 14, 2:42*pm, Adam Aglionby wrote:



On 14 May, 11:59, "Man at B&Q" wrote:

On May 14, 10:40*am, Mike Tomlinson wrote:

In article , Dave Plowman (News)
writes

That's how they modify the base colour. Which with 'white' types is
usually blue.

If the original light is blue, why did it take so long for blue LEDs to
come out? *(You can't get away from them now.)

They've been around for years (20+ at least) but were very expensive
compared to the usual red. Now there's a mass market for blue (to make
white ones), you can pick up blue ones for a lot less.

MBQ

Blue LED been around since early 80`s in silicon carbiide form, couple
problems , output was tiny and maunfacturing *yield was like 1 in
10,000, Siemens offered a blue SiC LED , about 80 quid each for the 5
mm in late 80s.

Big breakthrogh is down to one man in the late 90s, Shuji Nakamura who
developed with aid of a lab assistant and funding of his employers,
Nichia, *Galium Arsenide blue LEDs with far better output and yield.

Nichia`s main buiness being CRT and lighting phosphors Mr Nakamura
went on to develop the white LED.

http://archive.sciencewatch.com/jan-...2000_page3.htm

Actually Gallium Nitride for blue LEDs. Gallium Arsenide produces
Infra Red LEDs. "Ye cannae change the laws o'physics".

MBQ

Darn looking at too many CCTV illumnators recently ;-)

Cheers
Adam