Re: TI-H: hey (cont.)
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Re: TI-H: hey (cont.)
Because the color of the LED is determined primarily by the semiconductor
material used. Blue leds were theoretically possible, and they had some lab
models, but for many years they were unable to find a reliable material and
manufaturing method to make them.
They finally did, and now we have them. Due to the low demand (when compared
with red, green and amber leds) they are still 'expensive'.
White LEDs are either blue LEDs with a phosphorescent coating on them which
produces white light when hit by the specific wavelength of the blue LED, OR
they are LEDs with red blue and green LEDs in them. It's less expensive the
first way, but the second way can also by used to produce nearly any visible
color.
-Adam
Markus Räty wrote:
>
> Jumping a little ot here, but would you happen to know why blue is so hard
> to make? I kinda started wondering a few years ago when I often worked with
> LEDs and noticed that I could get one type of red LEDs for $1 a piece and a
> blue one of the same type would cost around $11. What's the story behind
> this?
>
> Markus Räty
> (markus.raty@usa.net)
>
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