Homebrew PCBs

Using an LCD instead of a transparency saves you only the very small step of
printing the transparency.  All the optics and alignment issues remain pretty 
much the same, you simply replace a printed transparency with a LCD image.

See the following URLs for discussion of home-built LCD projectors: 
<http://www.hommie.net/>
<http://www.louisville.edu/~wchall01/diyprojector/>
<http://www.diyprojection.com/>
<http://diyaudio.com/forums/forumdisplay.php?forumid=20>

----
Doug

On Fri, May 23, 2003 at 03:36:00AM -0500, Neil wrote:
> Alright, call me crazy, but an idea just occurred to me, and I can't see why 
> it can't work.  To me, the most difficult (expensive, complicated, 
> unreliable, etc) part of creating a PCB is getting the pattern laid out on 
> the board so it can be exposed, etc.  The rest is science ... standard 
> procedure, standards times, standard results.  Yes, laying out the pattern 
> can be science, but at a higher price, and still takes time to line up the 
> image transparencies, etc.
> 
> So this idea just randomly came to me ... why not use a projector to project 
> the image on the board.  Use a positive-coated board and an XGA LCD 
> projector, with a UV bulb instead of the usual bulb.  I get quite good 
> results at 300dpi, so if we go with a projector resolution of 1024x768 for 
> now, that's about 3.4" x 2.5".  There may need to be some optical 
> manipulation done to get it to focus clearly at that distance, and a bunch of 
> other little things sorted out (such as calibration for 
> non-linear/inconsistent pixel spread), but I can't see why it can't work.  
> No, it's not cheap, but I believe it would be really fast, going from 
> computer straight to PCB.
> 
> Maybe this has been thought of or done already?  Or maybe I'm going off the 
> deep end?
> 
> Cheers,
> -Neil.
> 
> 
>