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.
>
>
>