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Subject: Re: [Homebrew_PCBs] UV photoplotter

From: Roland Harriston <rolohar@...>
Date: 2006-12-21

It seems to me that I remember (many years ago) that there was a
"coordinatograph" type machine that we used
in the microwave design lab that did something like what is proposed
here. The difference would be that in the
device I recall, the "media" was like litho film. A light source moved
across the surface of the litho film, tracing
a microwave stripline configuration that was transferred to the film,
the geometry of the stripline configuration
having been programmed into the "coordinatograph" in X/Y coordinates.

The litho film negative that was produced was many times the size of the
actual stripline. A photographic
reduction process was used to establish the actual stripline size. The
advantage appeared to be that the
actual stripline dimensions were very accurate due to the photographic
reduction process.

I think the photoreduction process was, at one time, quite common in the
microelectronics industry
in making masks for integrated circuit fabrication. No doubt, other
techniques are used nowadays.

There are some rather powerful UV LED's available. Check out the UV
LED's in the latest
BG Micro online catalog at the URL below.

http://bgmicro.com/

Others on the list are probably familiar with the above described technique.

Roland F. Harriston



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