Homebrew PCBs

Hi Jeff,

I bought a 40x objective from a seller on eBay and did a few tests with an ordinary white led and found that you can indeed get a very fine spot. The weight of the objective, however, would probably
preclude its use as a pen in say, an X-Y plotter. Therefore, an X-Y table is needed and now you are getting into the realm of CNC and things start to get expensive. I started to look at laser X-Y scanners,

http://www.ermicro.com/blog/?p=1622

http://elm-chan.org/works/vlp/report_e.html

My conclusion here is that the beam diameter is most likely to be too large for for PCB work and some extra optics such as a plano convex or a ball lens would be necessary to get the beam to a spot as it is coming off the mirror. In this regard search for F-theta lenses. The problem with optical approaches is the mechanical precision necessary in the placement of components. You could of course use DLP if you have plenty of money,

http://www.ti.com/analog/docs/memsmidlevel.tsp?sectionId=622&tabId=2455

I have largely perfected toner transfer for one-off purposes so all of this is mainly of academic interest for me.

Baxter

--- In Homebrew_PCBs@yahoogroups.com, "Jeff Heiss" <jeff.heiss@...> wrote:
>
> Hi Baxter,
> 
>  
> 
> I read a message from a few months ago on the UV Pen discussion that you
> were experimenting with a UV LED and a microscope objective to focus the LED
> down for resist developing.  How are your experiments going?  Any findings
> yet?