Re: Can UV LEDs erase EPROMs?

From: Don Klipstein (don_at_manx.misty.com)
Date: 11/28/04 

Date: Sun, 28 Nov 2004 06:49:20 +0000 (UTC)

In article <cndqd.85990$Le1.1898457@news20.bellglobal.com>, Kim wrote:
>This is slightly off-topic, but I bought a bunch of uv Leds, hoping that I
>could use them to sterilise toothbrushes. I was informed by someone on the
>newsgroup that they were far too underpowered, and not the correct
>wavelength to do the job.

  UV LEDs produce nearly enough nothing at wavelengths much below 350 nm.

  There is a 350 nm model with extremely low output power, and otherwise
UV LEDs have peak wavelength 365 nm and up. All easily available ones at
any reasonable price have a peak wavelength 370-375 nm or more. Spectral
content falls rapidly at wavelengths shorter than the peak wavelength.

  The usual lamps used to erase EPROMs and kill bacteria do that with 254
nm. I have heard of sunlight erasing EPROMS over several days or a couple
weeks in Arizona, and I would guess wavelengths near the shortest getting
through the atmosphere in any amount (around or possibly slightly over 300
nm) are responsible. I doubt Arizona sunlight sterilizes toothbrushes,
although a car parked in the sun on a bad day in Phoenix can get hot
enough to kill a lot of bacteria.

 - Don Klipstein (don@misty.com)

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