Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Blue and UltraViolet LED's
Message-ID: <1990Jul18.033929.13442@zoo.toronto.edu>
Organization: U of Toronto Zoology
References: <17596.2699d803@uctvax> <1990Jul11.233848.29098@zoo.toronto.edu> <1551@oucsace.cs.OHIOU.EDU> <38692@cci632.UUCP>
Date: Wed, 18 Jul 90 03:39:29 GMT

In article <38692@cci632.UUCP> rdi@ccird3.UUCP (Rick Inzero) writes:
>Unless there's some problem with actually generating the UV from the 
>light emitting diode chip itself...  So far, all I remember is postings 
>that the plastic housing was the problem.

That's a side issue; the hard part is getting short-wavelength emissions
out of semiconductors at all.  (Nondestructively, that is! :-))  It's not
a packaging problem that has delayed useful blue LEDs until quite
recently.  The mechanisms and materials that fairly easily yielded IR,
red, yellow, and green simply can't be stretched to blue, let alone
further.  My impression is that the blue ones are a triumph over major
difficulties, and nobody's in a hurry to tackle UV.
-- 
NFS:  all the nice semantics of MSDOS, | Henry Spencer at U of Toronto Zoology
and its performance and security too.  |  henry@zoo.toronto.edu   utzoo!henry