Homebrew PCBs

Not sure if people have heard about pico projectors that are slowly making their way out into the market. The ones that I have seen so far use LEDs as the light source. I would think it should be possible to replace those visible light LEDs with UV LEDs to make a maskless exposure system. 

The resolutions of most of the ones I have seen are somewhat limited, but I think there will be 1080p capable projectors on the market in relatively short order. 

If I were not already in the middle of a couple of projects already, I would buy one and try it. However I thought I would toss that idea out there for others to think about.

The pico projectors I've seen are low res, less than NTSC TV.

And 1080i isn't even as high a resolution as my 19" monitor.

It has been said before here that for a laser printer or inkjet to be high enough res for making fine pitch PCBs, they must be at least 600dpi.

Take 1280x1024 and shrink it down to 600dpi, that's about 2x1.6 inches. Not very big.

Steve Greenfield

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" <javaguy11111@...> wrote:

>
> Not sure if people have heard about pico projectors that are slowly making their way out into the market. The ones that I have seen so far use LEDs as the light source. I would think it should be possible to replace those visible light LEDs with UV LEDs to make a maskless exposure system. 
> 
> The resolutions of most of the ones I have seen are somewhat limited, but I think there will be 1080p capable projectors on the market in relatively short order. 
> 
> If I were not already in the middle of a couple of projects already, I would buy one and try it. However I thought I would toss that idea out there for others to think about.
>

"javaguy11111" <javaguy11111@...> writes:
> The resolutions of most of the ones I have seen are somewhat
> limited, but I think there will be 1080p capable projectors on the
> market in relatively short order.

The last board I did was a lowly 5x2" and was 14,400 "pixels" across.
I think 1080i is nowhere near enough resolution for PCB exposure.

Why not focus the projection and move either the projector or PCB while only exposing portions of the PCB at any one time. Essentially maskless lithography.

There are a products that do just this kind of exposure activity emerging in the semiconductor industry. Some websites after a quick google - 

http://en.wikipedia.org/wiki/Maskless_lithography
http://www.intelligentmp.com/
http://www.freepatentsonline.com/6764796.html
http://www.lumarray.com/
http://focus.ti.com/pdfs/dlpdmd/Digital_Projection_of_UV_Light_is_Enabling_New_Markets1.pdf

I thought the plasma TV without phosphorus was a real neat idea.

Joseph


--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

>
> "javaguy11111" <javaguy11111@...> writes:
> > The resolutions of most of the ones I have seen are somewhat
> > limited, but I think there will be 1080p capable projectors on the
> > market in relatively short order.
> 
> The last board I did was a lowly 5x2" and was 14,400 "pixels" across.
> I think 1080i is nowhere near enough resolution for PCB exposure.
>

You are reinventing the 70's gerber photo plotters!

See http://www.artwork.com/gerber/appl2.htm.

Todays photo plotters use an lcd like a projector and raster not only a
beam but an small portion of the artwork. There are dozens of problems
in DIY from a projector and UV light source which don't worth the bits
here.

Two home made raster photo plotters with single laser beam.
http://pico-systems.com/photoplot.html
http://blog.makezine.com/archive/2008/10/microcontroller_based_pho.html
(like the crap ones bungard and others sell)

I could write full pages of the pros and cons off doing this. Or i can
tell you dozens of other ideas regarding similar things like modifying a
laser printer to do UV print or using a laptop tft display with a UV
backlight, and so on.  But none off this worth the bits.

If you want to dedicate yourself to any project why not to direct inkjet
print ? You won't need to have anything UV sensible on the pcb just
print and cure. You only need to find something suitable as your ink.

Or direct laser print? 
http://www.laserpcb.com

We are homebrews but we don't need to be 50 years behind the industry.

On Fri, 2009-07-03 at 14:03 +0000, gsi11135 wrote:
> 
> 
> Why not focus the projection and move either the projector or PCB
> while only exposing portions of the PCB at any one time. Essentially
> maskless lithography.
> 
> There are a products that do just this kind of exposure activity
> emerging in the semiconductor industry. Some websites after a quick
> google - 
> 
> http://en.wikipedia.org/wiki/Maskless_lithography
> http://www.intelligentmp.com/
> http://www.freepatentsonline.com/6764796.html
> http://www.lumarray.com/
> http://focus.ti.com/pdfs/dlpdmd/Digital_Projection_of_UV_Light_is_Enabling_New_Markets1.pdf
> 
> I thought the plasma TV without phosphorus was a real neat idea.
> 
> Joseph
> 
> --- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
> >
> > "javaguy11111" <javaguy11111@...> writes:
> > > The resolutions of most of the ones I have seen are somewhat
> > > limited, but I think there will be 1080p capable projectors on the
> > > market in relatively short order.
> > 
> > The last board I did was a lowly 5x2" and was 14,400 "pixels"
> across.
> > I think 1080i is nowhere near enough resolution for PCB exposure.
> >
> 
> 
> 
> 
>

Looks like the copper sheets could be used for inkjet as well.  I wonder 
what else the sheets could be attached to (fr4 can't be the only option...)?



Simao Cardoso wrote:

>
>
> Or direct laser print? http://www.laserpcb.com <http://www.laserpcb.com>
>
>

On Fri, 2009-07-03 at 10:11 -0500, Troy wrote:
> Looks like the copper sheets could be used for inkjet as well. I
> wonder 
> what else the sheets could be attached to (fr4 can't be the only
> option...)?

There are some power modules that use smd transistors soldered on very
thin fr4 boards which are glued to thick aluminium plate. It works at
the same time as pcb and as cooler. They are  single sided and NO trough
holes.


>