Homebrew PCBs

Here is another interesting article on photoresists exposure.

http://www.circuitree.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2133,3647,00.html

Doing some searching, the photoresists typically have a sensitivity of 
around 60 to 100mJ/cm^2 at 350nm. So if you know the light intensity of 
your UV LED you can estimate time for exposure. I have a feeling UV 
LED's are far too weak to exposure resists.

Adam


Thomas wrote:

> does anyone have any info about the photo Resist UV Spectrum range for "Kinsten Presensitized" PCB's ?
> I would like to look at this Laser/ UV LED in more detail , speed is not impotant right now but to get it working first will be nice ...
> Thomas
> 
> 
>   ----- Original Message ----- 
>   From: sciciora 
>   To: Homebrew_PCBs@yahoogroups.com 
>   Sent: Tuesday, October 05, 2004 8:31 PM
>   Subject: [Homebrew_PCBs] Re: OHP Film & Laser Printers, UV Laser Diode
> 
> 
> 
>   I did some thinking about this as well.  I found on this list that
>   some pre-sensitised PCB are sensitive in the range of 340 to 400 nm,
>   and peak at about 360nm.  The LED that I bought has an output at
>   405nm.  As far as power, just move slower!  A co-worker's friend, who
>   works with optics as a consultant, said it wouldn't be hard to pick
>   some lenses and fiber from Edmund scientific to foccus most of the
>   LED's light into the fiber.  And if I were more serious I might be
>   able to get him to help me design something, but due to too many
>   projects, trying this will most likely just be a through experimnet
>   for me...
> 
>   - Steven Ciciora
> 
>   --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon_heller@h...>
>   wrote:
>   > 
>   > >From: "Mike" <yahoo@d...>
>   > >Reply-To: Homebrew_PCBs@yahoogroups.com
>   > >To: Homebrew_PCBs@yahoogroups.com
>   > >Subject: [Homebrew_PCBs] Re: OHP Film & Laser Printers,  UV Laser Diode
>   > >Date: Sun, 03 Oct 2004 00:41:20 -0000
>   > >
>   > >
>   > >
>   > >--- In Homebrew_PCBs@yahoogroups.com, "Thomas" <teecee@c...> wrote:
>   > >
>   > > > This UV Laser thing has me thinking (dangerous I know)  so slap me
>   > >for bringing this up !! but during a few search's I come across some
>   > >info that uses a UV Laser Diode in a DVD-R Burner & goes on about
>   > >Photoresist being part of the Layer that records the Data, if its
>   > >similar stuff or not i dont know. Maybe the UV Laser is to small and
>   > >possible the focal point could be changed  to get a wider beam for
>   > >Exposure, sounds easy enough but I bet it aint !!
>   > >
>   > >Possibly more useful than Lasers, Non-laser UV LEDs are available on
>   > >Ebay etc for around 10-20c each. They seem to work fine directly off
>   > >2x1.5v AA cells. The beam is divergent at an angle of approx 20
>   > >degrees on the ones I have. I would imagine that it would be
>   > >focussable with relatively inexpensive lenses too, or get a bunch of
>   > >fibre optics and adapt an old dot matrix printer :o)
>   > 
>   > 
>   > The wavelength needs checking, to make sure it is correct. The power
>   also 
>   > needs to be checked, I don't think that UV LEDs will have enough power.
>   > 
>   > Leon
> 
> 
> 
> 
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