Homebrew PCBs

James wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, James Bishop <bishopaj@...> wrote:
>> It might also have something to do with the UV wavelength. I think
>> LEDs have a longer wavelength, close to purple, while the tubes might
>> be further into the UV range. This may affect exposure time or
>> resolution.
>>
> 
> Fluorescent tubes emit light in sharp peaks of fairly specific wavelenghts. There are several peaks produced by the mercury vapor discharge itself, and others produced by the phosphor coating which is excited by absorbing the short wave UV from the discharge. Ordinary glass absorbs shortwave UV, so special germicidal and ozone producing tubes are made of quartz.
> 
> LEDs tend to emit peaks as well, but the wavelengths are indeed longer, I don't think anyone has come up with a true UV LED, the closest they get is deep violet which will excite many UV sensitive materials but the intensity is much lower than that of a mercury discharge which is a very strong UV emitter.

The power level from array LEDs is high.

http://www.phoseon.com/
http://www.leduv.com/
http://www.jentonuvled.com/

http://www.google.com.au/#hl=en&source=hp&q=%22uv+led%22&btnG=Google+Search&meta=&aq=f&oq=%22uv+led%22&fp=4fcec8be4c0b548b