Photo etching
Benoit A. Tellier
I need resources on how to get started in photo etching (books!).
I have darkroom experience in photography and circuit board design.
B
Don Stauffer
I also hope no one is offended or upset, as I am in the same boat. Have
been meaning to start, but want others to go first :-)
I am wondering about even skipping the photo process (though we DO have
a darkroom) and try some of those 'iron-on' transfer sheets where the
iron-on material is supposed to be etch resistant.
--
Don Stauffer in Minneapolis
home web site- http://home1.gte.net/stauffer/
home email- stau...@gte.net
work email- stau...@htc.honeywell.com
Don Foreman
Kodak used to have application notes on the subject (25 years ago) when KPR
was a leading "resist". I don't know if they're still into that or not.
Benoit A. Tellier <cha...@cam.org> wrote in article
<35D7B84C...@cam.org>...
Don Foreman
Don Stauffer <stau...@htc.honeywell.com> wrote in article
<35D82E...@htc.honeywell.com>...
>
> I am wondering about even skipping the photo process (though we DO have
> a darkroom) and try some of those 'iron-on' transfer sheets where the
> iron-on material is supposed to be etch resistant.
>
I just made a batch of printed circuit boards for the mole zappers, so I'm
interested in this again.
You don't need a darkroom. The stuff isn't that sensitive. It takes
about an hour in direct sunlight or 10 minutes 1 foot away from a 400-watt
sunlamp to expose them. Look for one of those quartz-tube mercury vapor
sunlamps (Sperti is one brand) at garage sales or Goodwill.
I haven't tried the special transfer sheets yet (intend to soon) but I've
noted that when making transparencies (vu-grafs) of artwork on laser
printers or photocopiers, there are tiny voids -- pinholes -- in the black
parts. Maybe the toner sticks better to the special paper.
You can buy positive-working resist in a spraycan from some electronics
stores. It shoots like a lacquer, "develops" in aqueous chemistry. KPR
was negative-working (the pattern left is where light does not hit),
developed in xylene -- smelly stuff to have indoors. KPR would stick to
about anything, resist about anything, but it was a mess to put on. The
circuit-board stuff works fine on circuit boards, but I haven't tried it on
other materials or in etchants other than ferric chloride.
Keep us posted on your progress, please. This is a thread of interest to
me, and maybe to several others.
DoN. Nichols
Don Foreman <forem...@htc.honeywell.com> wrote:
>
>
>Don Stauffer <stau...@htc.honeywell.com> wrote in article
><35D82E...@htc.honeywell.com>...
>
>>
>> I am wondering about even skipping the photo process (though we DO have
>> a darkroom) and try some of those 'iron-on' transfer sheets where the
>> iron-on material is supposed to be etch resistant.
Well ... I might as well be the third "Don" in this thread. :-)
>You can buy positive-working resist in a spraycan from some electronics
>stores. It shoots like a lacquer, "develops" in aqueous chemistry. KPR
>was negative-working (the pattern left is where light does not hit),
>developed in xylene -- smelly stuff to have indoors. KPR would stick to
>about anything, resist about anything, but it was a mess to put on. The
>circuit-board stuff works fine on circuit boards, but I haven't tried it on
>other materials or in etchants other than ferric chloride.
If it is anything like the AZ-101 series of positive photo-resists
made by Kepco, it is soluble in strong alkalies, such as NaOH, so it makes a
*very* poor choice for making etched anodized aluminum nameplates. (Been
there -- regretted the attempt. :-)
>Keep us posted on your progress, please. This is a thread of interest to
>me, and maybe to several others.
Always,
Thanks,
DoN.
--
NOTE: spamblocking on against servers which harbor spammers.
Email: <dnic...@d-and-d.com> | Donald Nichols (DoN.)|Voice (703) 938-4564
My Concertina web page: | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
James Wilkins
>
> I haven't tried the special transfer sheets yet (intend to soon) but I've
> noted that when making transparencies (vu-grafs) of artwork on laser
> printers or photocopiers, there are tiny voids -- pinholes -- in the black
> parts. Maybe the toner sticks better to the special paper.
Try filling it in with a black marker. Some of them will wipe off the
clear acetate but stick to the toner nicely. I haven't tried making a
circuit board this way (I either send out Gerber files or mill the board
on a T-Tech CNC machine) but it makes nice black labels with graphics on
a clear background.
jw
Benoit A. Tellier
Actually I'm looking into making finely detailed metal parts for scale models
(hence the "hope I'm not offending notice").
Many manufacturers sell detailing kits of photo-etched materials (cockpit,
dash, engine details, ...).
In the more advanced detailing kits, there are details on the etched pieces...
Glenn Goens
wrote:
>If no one is offended because this may not belong here...
>
>I need resources on how to get started in photo etching (books!).
>
>I have darkroom experience in photography and circuit board design.
>
>B
>
Try this site for starters...
http://www.ijtk.demon.co.uk/2mm/magazine.htm
Hope this helps
Glenn Goens -- gdgo...@mail.idt.net
Don Foreman
A firm in St. Paul (Buckbee Mears) makes (or made) all manner of very
finely-detailed things by photoetching, like shadow masks for CRT's. I
think the Braun gold-plated "permananent coffee filter" is probably
photoetched. Integrated circuits are photo-etched to sub-micron
tolerances. Those are beyond the reach of home shop machinists and
hobbyists, but making things like finely detailed metal parts for scale
models, decorative nameplates, little springs, dials, etc could be of
great interest to this group.
Benoit A. Tellier <cha...@cam.org> wrote in article
<35D8DED3...@cam.org>...
Don Foreman
withstand about anything; I know they used it for anodized aluminum
nameplates. Don't know if it's still available, or what has replaced it.
DoN. Nichols <dnic...@d-and-d.com> wrote in article
<6r9pak$o...@izalco.d-and-d.com>...
Don Foreman
as resist right on the copper.
James Wilkins <je...@mitre.org> wrote in article
<35D8A1CD...@mitre.org>...
DoN. Nichols
Don Foreman <forem...@htc.honeywell.com> wrote:
>The positive stuff is probably the Kepco stuff, relabelled. KPR would
>withstand about anything; I know they used it for anodized aluminum
>nameplates. Don't know if it's still available, or what has replaced it.
Yep! KPR is a negative-acting resist (from Kodak), and is pretty
good against almost anything other than solvents like 1,1,1 Tricholorethane.
:-) That's what I wound up using for the nameplates -- though I had the fun
of having to spin the resist onto them.
Enjoy,
DoN. Nichols
There is a red paint from Kodak used for such things. I used that
on litho film if I hadn't done the tape layout quite tight enough, when I
was building up really wide traces, and tapering wide areas down to pads.
Randy Gordon-Gilmore
>I need resources on how to get started in photo etching (books!).
Take a look at my webpage at http://www.netcom.com/~gord-gil for a description
of my home photoetching setup.
One update I need to make to the site is the fact that Morton has discontinued
their Laminar resist in favor of an improved formulation, but it is only
available in 250-foot and up rolls.
DuPont makes a roughly equivalent resist called Riston, which Think & Tinker
(http://www.thinktink.com) sells in 50- and 100-foot rolls. This appears to be
the best way to go for dry-film resist at this time.
Best regards,
Randy
--
Randy Gordon-Gilmore ,----.___________ ______________ _________________
ProtoTrains // = = === == || == == == = || == == == = == =|
Benicia, CA, USA /-O==O------------o==o------------o==o-----------o==o-'
gord...@ix.netcom.com -=[CB&Q 9900 "Pioneer Zephyr"]=-
Geert Knudsen
> I haven't tried the special transfer sheets yet (intend to soon) but I've
> noted that when making transparencies (vu-grafs) of artwork on laser
> printers or photocopiers, there are tiny voids -- pinholes -- in the black
> parts. Maybe the toner sticks better to the special paper.
Hi Don,
Putting two prints on top of each other helps me avoid those voids when
making circuit boards. The chance that both transparencies should have a
pinhole in the same place is negligible.
Regards/Geert
Scott A. Moore
forem...@htc.honeywell.com says...
>
>That's why it is of interest to this group.
>
>A firm in St. Paul (Buckbee Mears) makes (or made) all manner of very
>finely-detailed things by photoetching, like shadow masks for CRT's. I
>think the Braun gold-plated "permananent coffee filter" is probably
>photoetched. Integrated circuits are photo-etched to sub-micron
>tolerances. Those are beyond the reach of home shop machinists and
Naw. Starting at $500 you can make your own integrated circuits, at home,
in your spare time (the tools are free... $500 is a brokered silicon
charge).
My personal guess is that any reasonably flat peice of metal can be
photoetched to precision if you are willing to invest as much in
equipment as a good photographer is.
[sam]
Bill S.
In a hurry, I used a Sharpie black pen to draw a circuit on the copper side
of an unfinished PC board. Put it in Radio Shack's Ferric Chloride
solution and after about 20 minutes had a circuit board. I removed the ink
with finger nail polish remover. It may have been ugly, but it worked.
When I had more time, I used the same technique that is outlined in:
http://web.wt.net/~geotek/nars/pcboards/pcboards.htm
It looks a lot better.
Bill
---------------
James Wilkins <je...@mitre.org> wrote in article
<35D8A1CD...@mitre.org>...
> Don Foreman wrote:
> >
> > I haven't tried the special transfer sheets yet (intend to soon) but
I've
> > noted that when making transparencies (vu-grafs) of artwork on laser
> > printers or photocopiers, there are tiny voids -- pinholes -- in the
black
> > parts. Maybe the toner sticks better to the special paper.
>
> Try filling it in with a black marker. Some of them will wipe off the
jesse_brennan
acetate photocopy with an household iron (teflon faceplate best). Photo copies
tend to have pinholes that can be patched with a permanent marker pen. Also I
use a thick shelac colored with powdered graphite to correct or patch images.
An even better material is a photocopy transfer material called PNP blue that is
printed with a photocopier or laser printer. This material is available from:
Techniks Inc
po box 463
Ringoes NJ 08551
908-788-8249
908-788-8837 FAX
Jesse
Don Foreman
Scott A. Moore <samiam...@cisco.com> wrote in article
<6rbbpk$atd$2...@news-sj-2.cisco.com>...
> In article <01bdca60$f8c25b40$6a45...@mn65-foreman.htc.honeywell.com>,
> forem...@htc.honeywell.com says...
> Naw. Starting at $500 you can make your own integrated circuits, at home,
> in your spare time (the tools are free... $500 is a brokered silicon
> charge).
Knowing how might help. Many of us don't.
>
> My personal guess is that any reasonably flat peice of metal can be
> photoetched to precision if you are willing to invest as much in
> equipment as a good photographer is.
How? What do we need? What do you use for resist? Etchants for various
materials? Care to share, please? A dissertation on this might be a
welcome addition to the dropbox.
Don Foreman
Don Foreman
Don Foreman <forem...@htc.honeywell.com> wrote in article
<01bdcac7$0cd61020$6645...@mn65-foreman.htc.honeywell.com>...
Don Foreman
DoN. Nichols <dnic...@d-and-d.com> wrote in article
<6rb4e0$q...@izalco.d-and-d.com>...
>
> Yep! KPR is a negative-acting resist (from Kodak), and is pretty
> good against almost anything other than solvents like 1,1,1
Tricholorethane.
> :-) That's what I wound up using for the nameplates -- though I had the
fun
> of having to spin the resist onto them.
>
What a mess! Sticky cotton candy from the flyoff.
Is KPR still available? Wonder if you could thin it and shoot it with a
spraygun?
Don Foreman
works great.
I wonder if a xenon electronic photoflash might work? If it did, you could
get it highly collimated with a good reflector, because it's more of a
point source to begin with.
I think I recall that sunlight is about 1000 watts/meter (don't recall at
what latititude). A 15" circular "spot" of light would contain a 10" x 10"
square workpiece. 60 seconds of sunlight on this area (0.114 sq m) would
irradiate it with 6840 joules of energy. A 50 watt-second photoflash
popped 136 times gives you 6840 joules. The xenon flash is an arc
discharge, so I expect there's plenty of UV in it. If you could get down
to a 8" circle, then you'd only need about 40 shots.
Sittin' in the sun is easier, no question.
Sunlamps work pretty well for PC boards, cost about $20 last time I looked.
Collimation isn't great, but better than fluorescent tubes.
Randy Gordon-Gilmore <gord...@ix.netcom.com> wrote in article
<6rb9sv$6...@dfw-ixnews3.ix.netcom.com>...
William L. Brown Jr.
Don Foreman <forem...@htc.honeywell.com> wrote:
>I see you've built a light source from UV fluorescent tubes. Probably
>works great.
>
>I wonder if a xenon electronic photoflash might work? If it did, you could
>get it highly collimated with a good reflector, because it's more of a
>point source to begin with.
Since the process is essentially that of making a contact print, is
collimation really an issue? One would want to be sure that the emulsion
side is against the exposure, but IIRC that's always a good idea anyhow.
--+---+ \/ -bill
++---+ |[]]|_^_[] wlb...@netcom.com
_|____+-+___|____|_ Concord, CA
| o+o +-+ <>--<>-= \ C-250 #302 - "Amazing Grace"
John Lee
>Benoit A. Tellier wrote:
>> If no one is offended because this may not belong here...
>> I need resources on how to get started in photo etching (books!).
>> I have darkroom experience in photography and circuit board design.
>I also hope no one is offended or upset, as I am in the same boat. Have
>been meaning to start, but want others to go first :-)
>I am wondering about even skipping the photo process (though we DO have
>a darkroom) and try some of those 'iron-on' transfer sheets where the
>iron-on material is supposed to be etch resistant.
There are frequently some interesting threads on this subject on sci.
electronics. design
John
Remove x from e-mail address to reply
DoN. Nichols
Don Foreman <forem...@htc.honeywell.com> wrote:
>
>
>DoN. Nichols <dnic...@d-and-d.com> wrote in article
><6rb4e0$q...@izalco.d-and-d.com>...
>
>>
>> Yep! KPR is a negative-acting resist (from Kodak), and is pretty
>> good against almost anything other than solvents like 1,1,1
>Tricholorethane.
>> :-) That's what I wound up using for the nameplates -- though I had the
>fun
>> of having to spin the resist onto them.
>>
>What a mess! Sticky cotton candy from the flyoff.
Yep! Cleanup was a bear. There was a thinner version for hybrid
and semiconductor ICs. That made a lot less mess.
>Is KPR still available? Wonder if you could thin it and shoot it with a
>spraygun?
I don't know for sure, but there must be *something* which has
similar behavior, since thre are things which the AZ-101 from Kepro could
not do. Anodized aluminum is an obvious example. The thinner version
(KTFR, I think it was called) would have a better chance at being sprayed --
as long as you kept it in non-actinic light. Amber light was quite adequate
for working with it with no troubles.
Good Luck,
DoN. Nichols
William L. Brown Jr. <wlb...@netcom.com> wrote:
>In article <01bdcacc$c18ca100$6645...@mn65-foreman.htc.honeywell.com>,
>Don Foreman <forem...@htc.honeywell.com> wrote:
>>I see you've built a light source from UV fluorescent tubes. Probably
>>works great.
>>
>>I wonder if a xenon electronic photoflash might work? If it did, you could
>>get it highly collimated with a good reflector, because it's more of a
>>point source to begin with.
>
>Since the process is essentially that of making a contact print, is
>collimation really an issue? One would want to be sure that the emulsion
>side is against the exposure, but IIRC that's always a good idea anyhow.
Well ... given the earlier suggestion of avoiding pinholes by
stacking two copies, there *is* a benefit to be had from greater collimation.
Of course -- with a retouched negative produced from Kodak Photolith
Ortho (assuming that it is still available) there is no problem. And the
contrast available from such negatives is very high.
Enjoy,
Benoit A. Tellier
You are God!
Just one Q: Where'd you get the Titanium?
Randy Gordon-Gilmore wrote:
> In article <35D7B84C...@cam.org>, cha...@cam.org said...
>
> >I need resources on how to get started in photo etching (books!).
>
VAntonova
>what latititude). A 15" circular "spot" of light would contain a 10" x 10"
>square workpiece. 60 seconds of sunlight on this area (0.114 sq m) would
>irradiate it with 6840 joules of energy. A 50 watt-second photoflash
>popped 136 times gives you 6840 joules. The xenon flash is an arc
>discharge, so I expect there's plenty of UV in it.
Unfortunately, I think most of the UV will be absorbed by the glass around the
discharge. I think a TIG (or any welder) will make a much better source of UV.
Alex.
Spehro Pefhany
> Unfortunately, I think most of the UV will be absorbed by the glass around the
> discharge. I think a TIG (or any welder) will make a much better source of UV.
Platemakers used to use (before Hg arc lamps) a messy carbon arc. They can
be had for cheap at times, but are large. They have an exposure frame with
vacuum pump that ensures intimate (but not inappropriate, or wrong ;-) )
contact between the film (emulsion side) and the metal plate.
Plates are only exposed on one side, while you need registered exposures
on both sides to do the photo etching.
An enclosed set of small 4-8W fixtures from Home Despot, fitted with UV
_germicidal_ flourescent lamps would probably be the nicest setup to work
with. Arcs and Hg arc lamps are quite variable in output, the Hg arc ones
vary in brightness very significantly during an exposure.
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany "The Journey is the reward"
sp...@interlog.com
Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Scott A. Moore
forem...@htc.honeywell.com says...
;>
;>
;>
;>Scott A. Moore <samiam...@cisco.com> wrote in article
;><6rbbpk$atd$2...@news-sj-2.cisco.com>...
;>> In article <01bdca60$f8c25b40$6a45...@mn65-foreman.htc.honeywell.com>,
;>> forem...@htc.honeywell.com says...
;>
;>> Naw. Starting at $500 you can make your own integrated circuits, at home,
;>> in your spare time (the tools are free... $500 is a brokered silicon
;>> charge).
;>
;>Knowing how might help. Many of us don't.
www.mosis.com. Sorry, I looked, the price when up, it's $620 now, but
that is for 4 chips, so theoretically you get a chips for $155, bought
in quantity. The site has or links to all details on the process, and
where to get free software.
Of course there is a catch, the same one that applies to most good metal
work. Ya gotta know what you are doing.
;>>
;>> My personal guess is that any reasonably flat peice of metal can be
;>> photoetched to precision if you are willing to invest as much in
;>> equipment as a good photographer is.
;>
;>How? What do we need? What do you use for resist? Etchants for various
;>materials? Care to share, please? A dissertation on this might be a
;>welcome addition to the dropbox.
;>
I am an amateur metal worker, and amateur photographer/darkroom jockey.
Put them together and you get:
Crap. Probally. But the accuracies are definately there in photography.
If I did this I would start with a good enlarger/darkroom setup.
Past this, I'm sure there are better folks to get this info from.
[sam]
Alan Shinn
>
> DoN. Nichols <dnic...@d-and-d.com> wrote in article
> <6rb4e0$q...@izalco.d-and-d.com>...
>
> >
> > Yep! KPR is a negative-acting resist (from Kodak), and is pretty
> > good against almost anything other than solvents like 1,1,1
> Tricholorethane.
> > :-) That's what I wound up using for the nameplates -- though I had the
> fun
> > of having to spin the resist onto them.
> >
> What a mess! Sticky cotton candy from the flyoff.
>
> spraygun?
--
I used to do just that onto 1 ft square sheets. With one of those little
disposable spray things. I forget what I thinned it, with perhaps even
with official thinner.
Looking forward:
Alan Shinn
Experience the
beginnings of microscopy.
Make or buy your own replica
of one of Antony van Leeuwenhoek's microscopes.
visit http://www.sirius.com/~alshinn/
Spehro Pefhany
> Of course -- with a retouched negative produced from Kodak Photolith
> Ortho (assuming that it is still available) there is no problem. And the
> contrast available from such negatives is very high.
The film that Lintronics and their bretherin emit at service bureaus is
essentially the same as Kodalith. 100% black, no pinholes. You wouldn't
have to fiddle about with it, no retouching for maybe
$10-$15 a letter/legal size page.
If you are going to have emulsion to metal contact, you would have to make
two copies of the image, one emulsion up, one down. If you install the
lino printer driver and (preferably) use a program that understands the
proper PPD file you can get the full feature set of the imagesetter to
operate.
****BTW, what is a source for KPR? Anyone? *****
Jon Elson
Benoit A. Tellier wrote:
> If no one is offended because this may not belong here...
>
> I need resources on how to get started in photo etching (books!).
>
> I have darkroom experience in photography and circuit board design.
Here is a link that has interesting info.
Also, I have some info on my equipment and processes for printed circuit
etching at
http://www.artsci.wustl.edu/~jmelson/
Look under printed circuit board making. Sometime, I'll have to put in
some drawings and pictures. Right now it is just text.
If you have any questions, feel free to ask. I've been making PC boards
for 15+ years, and have tried a number of processes before finding
something that works consitently.
Jon
Martin H. Eastburn
Older EPROMS used 254 nM - nano-Meter wavelength - I had to get
an eraser... - Bought a sterializing floro tube from the local
electrical supply. 254nM was it. Notice: It is dangerous to look
at this wavelength with the eye. It will sunburn very rapidly.
I suspect this would be just fine. - Mine was a (maybe) 12" x 3/4"
tube. Fit in a standard under the counter type fixture.
This has been useful from time to time.
Martin
--
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
Martin Eastburn, Barbara Eastburn
@ home on our computer old...@pacbell.net
dann mann
screenprinting. We use photopositives and ordinary drafting vellums to
make stencils from.
The voids in the laser printer outputs can be retouched with an
opaqueing pen or technical pen for finer lines.
For ultimate accuracy you need the output form an Imagesetter. Go to any
local service bureau (see Yellow Pages) and for about 10 dollars they
will print your artwork directly on real film. It can be scaled up or
down from original size very simply. This output method is the finest
available, even better than the best repro camera work.
Many people overlook screenprinting as a simple and cheap way to apply
resists at home. Even the stencil process is quick and nothing fancy in
the way of equipment is required for good results.
For example, A nice screen that can be used virtually forever is only
about 15 dollars. A quart of black ink is 20$ but you could use alkyd
enamel paint.
I use the sun all the time as a UV source.
Actually it is the best point source you will ever find. Sandwich your
positive and stencil film with some 3M sprayment and leave in sunlight
for about 2 minutes. Works every time.
I would be happy to elaborate if anyone is interested. I could give
you suppliers and product names if you wish for small quantities of
everything you need and I would do so gladly.
To top it all off, it's fun and you can learn something new that is
related to metalworking, ( I print on metal and almost every other
substance known to man) Dann
DoN. Nichols
Spehro Pefhany <sp...@interlog.com> wrote:
>VAntonova <vant...@aol.com> wrote:
>
>> Unfortunately, I think most of the UV will be absorbed by the glass around the
>> discharge. I think a TIG (or any welder) will make a much better source of UV.
>
>Platemakers used to use (before Hg arc lamps) a messy carbon arc. They can
>be had for cheap at times, but are large. They have an exposure frame with
>vacuum pump that ensures intimate (but not inappropriate, or wrong ;-) )
>contact between the film (emulsion side) and the metal plate.
>
>Plates are only exposed on one side, while you need registered exposures
>on both sides to do the photo etching.
>
>An enclosed set of small 4-8W fixtures from Home Despot, fitted with UV
>_germicidal_ flourescent lamps would probably be the nicest setup to work
>with. Arcs and Hg arc lamps are quite variable in output, the Hg arc ones
>vary in brightness very significantly during an exposure.
I've used a frame which had 4 foot UV flourescents on both sides,
with the PC board and negatives sandwitched between two flexible mylar
films, with a vacuum pulled between them. It was really nice for making
double-sided PC boards. We never tried for multi-layer, however, because
that is a *lot* more work. :-)
Spehro Pefhany
> I've used a frame which had 4 foot UV flourescents on both sides,
> with the PC board and negatives sandwitched between two flexible mylar
> films, with a vacuum pulled between them. It was really nice for making
> double-sided PC boards. We never tried for multi-layer, however, because
> that is a *lot* more work. :-)
Yes, the hydraulic press for laminating the pre-preg is not a small
investment, either.
That would be an ideal setup for photo etching though. Did you buy or make
the vacuum frame? If the latter, how did you do it?
--
Don Stauffer
>
snip
> I use the sun all the time as a UV source.
> Actually it is the best point source you will ever find. Sandwich your
> positive and stencil film with some 3M sprayment and leave in sunlight
> for about 2 minutes. Works every time.
> I would be happy to elaborate if anyone is interested. I could give
> you suppliers and product names if you wish for small quantities of
> everything you need and I would do so gladly.
> To top it all off, it's fun and you can learn something new that is
> related to metalworking, ( I print on metal and almost every other
> substance known to man) Dann
I was wondering when someone would mention this. I was going to when I
saw dann's post. I have also used sun for UV source for circuit boards.
Of course, it doesn't work well at night or on really cloudy days, but
for the price you absolutely can't beat it!
--
Don Stauffer in Minneapolis
home web site- http://home1.gte.net/stauffer/
home email- stau...@gte.net
work email- stau...@htc.honeywell.com
Leon Heller
<reckl...@home.com> writes
>On 20 Aug 1998 01:19:19 -0400, dnic...@d-and-d.com (DoN. Nichols)
>wrote:
>
>> I've used a frame which had 4 foot UV flourescents on both sides,
>>with the PC board and negatives sandwitched between two flexible mylar
>>films, with a vacuum pulled between them. It was really nice for making
>>double-sided PC boards. We never tried for multi-layer, however, because
>>that is a *lot* more work. :-)
>
>(or more) sided board in a home shop environment? A lot of the PLCC
>devices I would like to use need lots of traces and vias quickly
>become necessary. I'd rather not have to put in rivets or solder
>wires through the board.
It's virtually impossible to do this at home and get it to work
properly. PCB manufacturers themselves have problems getting it right.
Leon
--
Leon Heller: le...@lfheller.demon.co.uk http://www.lfheller.demon.co.uk
Amateur Radio Callsign G1HSM Tel: +44 (0) 118 947 1424
See http://www.lfheller.demon.co.uk/dds.htm for details of a simple AD9850
DDS system. See " "/diy_dsp.htm for a simple DIY DSP ADSP-2104 system.
dann mann
foot stencil at 9am. It totally obscured sunlight. About 10 minutes
total exposure. I prefer the early hours because there is less risk of
overexposure and loss of contact due to heat build-up. I have made
screenprinting stencils with my frame setup to face an open door during
a midsummer shower and the results were fantastic.
DoN. Nichols
Reckless <reckl...@home.com> wrote:
>On 20 Aug 1998 01:19:19 -0400, dnic...@d-and-d.com (DoN. Nichols)
>wrote:
>
>> I've used a frame which had 4 foot UV flourescents on both sides,
>>with the PC board and negatives sandwitched between two flexible mylar
>>films, with a vacuum pulled between them. It was really nice for making
>>double-sided PC boards. We never tried for multi-layer, however, because
>>that is a *lot* more work. :-)
>
>So how does one go about making the plated-through vias on a double
>(or more) sided board in a home shop environment? A lot of the PLCC
>devices I would like to use need lots of traces and vias quickly
>become necessary. I'd rather not have to put in rivets or solder
>wires through the board.
I've done both of the last two. The process which I have heard
described involves first some mask on the boards, drilling them on some
really repeatable setup (ideally put the registration pin holes in there at
the same time), then wash with something conductive enough to get a start at
electroplating. (Perhaps graphite through the holes.) Connect to the foil
on both sides, and electroplate while flowing the solution through the holes
(or you will get rapid depletion of the chemicals there). Electroless tin
is sometimes a starting point, I think. Once you have that starting point,
you can electroplate at will. (This, of course, requires you to be able to
do good durable electroplating. :-)
Once that is done, strip off the mask, put on photoresist, (well,
the photoresist could be the mask, if you were willing to do all the plating
steps under controlled lighting conditions.)
Using the registration holes for alignment, expose the photoresist
(or for a large enough production run with no really high resolution
demands, silk-screen the resist on.)
Now -- if you're going to do more than double-sided, etch each side
which is going together, sandwich with an insulator with the holes also
pre-drilled, and plate as before,
>Another question way out there: what glue is used to laminate
>multi-layer boards?
Very thin uncoated material the same as the board's substrates (such
as G-10 glass-epoxy). A matching epoxy to that used to make the boards
themselves. Clamp and cure. For this, you probably only want the
registration holes until you have the various pairs of layers glued
together, then drill to expose the edges of the foil where needed, coat
through, and plate as before.
(Listen to me -- I sound as though I've done this before. Don't
believe it. Anybody who really *knows* this stuff is probably under a
non-disclosure agreement. :-)
> Any real good tricks to registration? My first
>thought is to make the board blank larger than necessary and use pins
>to register everything, then trim the board.
I would say that you should trim to size just after the registration
holes are placed in the board, perhaps after the etching of the two sides,
and *before* any clamping and gluing. You may want to (gently) sand the
edges after the stack is finished, but I think that shearing would be very
likely to break the boards apart near the point of shear, destroying your
nice plated-thrugh holes.
Good luck,
DoN. Nichols
Spehro Pefhany <sp...@interlog.com> wrote:
>DoN. Nichols <dnic...@d-and-d.com> wrote:
>
>> I've used a frame which had 4 foot UV flourescents on both sides,
>> with the PC board and negatives sandwitched between two flexible mylar
>> films, with a vacuum pulled between them. It was really nice for making
>> double-sided PC boards. We never tried for multi-layer, however, because
>> that is a *lot* more work. :-)
>
>investment, either.
>
>That would be an ideal setup for photo etching though. Did you buy or make
>the vacuum frame? If the latter, how did you do it?
How about neither? :-) We got it from another team which no longer
needed it. It *was* obviously commercial manufacture.
As for how to make it? Well ... this is working from a memory over
a decade old (probably closer to 15 years). Start with a piano-hinge. Make
a pair of aluminum frames, with grooves in the sides facing apart when the
piano hinge closes, and a second groove in one of the two mating surfaces.
Fill that groove with a big soft O-ring. The other mating frame is hollow
below the groove, and there are small holes drilled in the inside face of it
towards the area between the two sheets of vinyl. Stretch the clear vinyl
across the frame, and press retainers into the grooves. Add a fitting to
allow you to couple a vacuum line to the hollow frame. Add a toggle latch
to hold the two together enough to start the seal.
Mount the whole thing on long roller tracks, to slide into the
housing between the two rows of UV flourescents. Add a switch to turn the
vacuum pump on and off, and a timer for the exposure timing. Throw in an
interlock to turn off the lights whenever the frame is not fully seated and
sealing the aperture. Perhaps anohter to keep the timer from starting until
the vacuum is high enough. (low enough? :-)
When you switch on the vacuum pump, the two sheets of vinyl will
start pulling towards each other, touch first in the center, and firmly
clamp the negatives and the board together. (You want some kind of
registration fixture which doesn't add too much thickness while it keeps the
negatives in registration.)
I wish that I had space for that when it came up in a surplus sale a
few years later. :-(
Enjoy,
Martin H. Eastburn
I'm having a 22x22 " made - NRE is 4K, each is another 4k - 2 min.
Oh yea there was a price increase due to material - Cyno-acitate ?
Yea real nasty stuff if it is exposed to wrong conditions.
Registration is done on a special flat surface using unique pins.
Epoxy is used (some version ?) to cement while the boards are in a
press. - You must bake the boards first! - get out all moisture.
(less it steam up the center of the board).
The through hole plating is done after a masking of the etched board.
The plate is a thin layer of paladium (sp again) - typically just a
dip. (Tin plate can be done this way onto copper) Pladium does it on
anything. Then the board is electro-plated with copper. (not to much,
or the holes will fill). [naturally done after ajoining the two boards.]
then on to the next layer(s) - some via's don't go all the way through!
(often called blind via).
Good luck - complex board is best done by a shop.
ESH in Tempe Az will do a fine job. If you have some - just one -
cost will be high. Make some for a club - is ok....
I know ESH, used them for years (18-19) knew the founder and the
VP (both retired now lucky stiffs!) was my 'ole boss years ago.
The company is now part of Everitt Charles.
I've done a complex Pin Electronic card and many other pcb's through
them. NO kickback what-so-ever, wish there were!
Martin H. Eastburn
The edge is supported.
FR4 is a very common material now - G10 lost out to FR4 -
I think due to flame retard. I have a bunch of G10 thin and thick
double sided in the shop, waiting for something. I made some
fender washers out of one sheet.
Don Wilkins
<le...@lfheller.demon.co.uk> wrote:
>In article <35dfbc5d....@news.newsguy.com>, Reckless
><reckl...@home.com> writes
>>On 20 Aug 1998 01:19:19 -0400, dnic...@d-and-d.com (DoN. Nichols)
>>wrote:
>>
>>> I've used a frame which had 4 foot UV flourescents on both sides,
>>>with the PC board and negatives sandwitched between two flexible mylar
>>>films, with a vacuum pulled between them. It was really nice for making
>>>double-sided PC boards. We never tried for multi-layer, however, because
>>>that is a *lot* more work. :-)
>>
>>So how does one go about making the plated-through vias on a double
>>(or more) sided board in a home shop environment? A lot of the PLCC
>>devices I would like to use need lots of traces and vias quickly
>>become necessary. I'd rather not have to put in rivets or solder
>>wires through the board.
>
>It's virtually impossible to do this at home and get it to work
>properly. PCB manufacturers themselves have problems getting it right.
>
I wouldn't say impossible but if you don't do it right it ain't gonna
come out right either in the kitchen or in a commercial facility.
The key is cleanliness, proper sensitizing the BCB board (through the
hole), proper electroless plating followed by conventional
electrodeposition. Each part of the process must be done correctly
which leaves several opportunities for failure.
Murphy's law is always valid.
Randy Gordon-Gilmore
>Just one Q: Where'd you get the Titanium?
The 1/4" diameter shaft was a remnant from work, and the spider arms are 1/16"
diameter welding rod (I had to call around a bit to find this.
Aerospace-related welding supply shops are the best to try.)
An alternative to the 1/4" Ti might be a fiberglass rod of the same size. I
found unreinforced plastics to be either too weak and brittle (acrylic etc.) or
flexible (polyethylene etc.)
Best regards (and I'm glad you find the article useful!)
Randy Gordon-Gilmore
>Since the process is essentially that of making a contact print, is
>collimation really an issue? One would want to be sure that the emulsion
>side is against the exposure, but IIRC that's always a good idea anyhow.
Collimation is an issue when the resist itself is .0015" thick and details
you're etching are on the order of .006"-.008" with a material thickness of
..010" (this is etching halfway through from each side--actually a little more
than halfway through to reduce the cusping of the etched edges). And the
emulsion *needs* to be against the resist, or you get diffraction through the
film itself.
AS an aside, although PC boards and photoetching metal are similar in concept,
the details are much different. For example, the resist traces on PCB's are
generally very wide in proportion to the thickness of metal being etched. I've
tried the PnP Blue toner transfer material, without much success. The resist
tended to squash out laterally during the ironing, even though I used just the
weight of the iron as the directions suggest. This is probably immaterial for
PCB traces (as long as they don't bridge together), but for model parts it was
unusable.
Best regards,
Randy Gordon-Gilmore
>****BTW, what is a source for KPR? Anyone? *****
Kepro (http://www.kepro.com) sells it. I don't remember the name of the
company that took over making it from Kodak.
Randy Gordon-Gilmore
forem...@htc.honeywell.com said...
>I see you've built a light source from UV fluorescent tubes. Probably
>works great.
It works very well. Exposure time is about 2-1/2 minutes (I calibrate the
exposure every couple of sessions with a Stauffer step exposure wedge). I was
initially concerned with the low UV intensity versus sunlight, but the
exposures are beautiful, down to .005" to .008" lines and spaces.
>Sittin' in the sun is easier, no question.
It was a hassle though--trying to expose and develop during lunch hour at work.
The lamp unit lets me expose whenever I'm ready--and I can laminate and expose
in the same evening.
Don Stauffer
Gee, since this tends to be a DIY group, maybe we should come up with a
UV light meter. I know visible light intensity varies greatly with
degrees of cloudiness that the adapts well to, and does not realize
there is that much change. I suspect UV would be even worse.
Suppose we take some UV sensitive detector, find a low cost UV filter
(rejects most visible light) and put it into some integrator op amp
circuit. It could be calibrated on a sunny day. Then, on a cloudy day
one could watch it until needle or display reaches that same number.
Biggest hangup to me would be low cost UV filter. Any ideas?
Spehro Pefhany
> Gee, since this tends to be a DIY group, maybe we should come up with a
> UV light meter. I know visible light intensity varies greatly with
> Biggest hangup to me would be low cost UV filter. Any ideas?
Ideally, it would be an integrating UV meter, since intensity might vary
with time (as in the warmup of Hg arc lights, or with clouds passing
overhead if you are using the solar source). As far as a UV pass filter,
I am sure Kodak Wratten probably has something, but the price
might be high. Perhaps Edmund Scientific has something, I'll check later.
Don Foreman
use two photodetectors, one behind the haze filter and one not.Subtract the
filtered output from the unfiltered output with an op amp, and the
difference provides a UV measurement.
Might need to "trim" out differences in the two detectors by illuminating
the "meter" with light known to have little UV content (incandescant bulb)
and trimming it to zero.
I don't know if silicon photodetectors respond to 257 nanometer light or
not. I would think so -- that's higher energy than visible light-- but the
datasheets usually don't say.
Another possibility: Honeywell used to make a little gas-filled tube called
the "purple peeper" for flame sensing -- responded to to the UV in a flame
while ignoring incandescance in the combustion chamber. I think that
is now replaced with a solid-state sensor. Point is, UV sensors are used
in proving flame in combustion controllers. Ulrich will probably know what
they're using now. I think Mary Hibbs-Brenner developed the solid-state
version. I'll see what I can learn about this.
Don Stauffer <stau...@htc.honeywell.com> wrote in article
<35DD77...@htc.honeywell.com>...
> Biggest hangup to me would be low cost UV filter. Any ideas?
> --
Don Stauffer
>
> Don Stauffer <stau...@htc.honeywell.com> wrote:
> > Gee, since this tends to be a DIY group, maybe we should come up with a
> > UV light meter. I know visible light intensity varies greatly with
>
>
> with time (as in the warmup of Hg arc lights, or with clouds passing
> overhead if you are using the solar source). As far as a UV pass filter,
> I am sure Kodak Wratten probably has something, but the price
> might be high. Perhaps Edmund Scientific has something, I'll check later.
>
> --
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Spehro Pefhany "The Journey is the reward"
> sp...@interlog.com
> Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Yes, I specified in my post to feed the photo detector into an op amp
set up as an integrator.
Joshua_Putnam
>Yeah! A photographer's "haze" filter blocks UV, passes visible. So you
>use two photodetectors, one behind the haze filter and one not.Subtract the
>filtered output from the unfiltered output with an op amp, and the
>difference provides a UV measurement.
You can get UV-pass filters, e.g. B+W 484, made with Schott UG 3
glass, or B+W 403, using Schott UG 1 glass. 484 is deep violet
and transmits just a little visible light, while 403 is
visually black. They are expensive, unfortunately, around $35
in the mid-40 to 52mm sizes. I imagine there's an equivalent
Kodak Wratten gel for around $25 in 3x3 inch, though I don't
have full Wratten specs to check. Once nice thing with gels is
that you can cut them to size to replace the bright-light slide
on incident meters -- I do that with a no.87 gel for metering
near infrared.
--
Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
"My other bike is a car."
http://www.wolfenet.com/~josh/
Joshua_Putnam
>You can get UV-pass filters, e.g. B+W 484, made with Schott UG 3
>glass, or B+W 403, using Schott UG 1 glass. 484 is deep violet
>and transmits just a little visible light, while 403 is
>visually black. They are expensive, unfortunately, around $35
>in the mid-40 to 52mm sizes. I imagine there's an equivalent
>Kodak Wratten gel for around $25 in 3x3 inch, though I don't
>have full Wratten specs to check.
Noticed in some of my IR documentation that the Wratten 18A is
supposed to be equivalent to Schott UG 1, and that Hoya makes an
equivalent glass filter, U 360.
Spehro Pefhany
> Yes, I specified in my post to feed the photo detector into an op amp
> set up as an integrator.
Oops, you did. Sorry I didnt read carefully., it could be done digitally
too, by accumulating counts from the reading.
I dont see anything inexpensive in the Edmund Sci. catalog.
The platemaker I have here has an integrating sensor/control in it, but I
dont see any obvious markings on the sensor.
The ionization sensors that someone mentioned are used in purple-peeper
and Fire-eye detectors might be coaxed into giving an analog signal
somehow.
Spehro Pefhany
> You can get UV-pass filters, e.g. B+W 484, made with Schott UG 3
> glass, or B+W 403, using Schott UG 1 glass. 484 is deep violet
> and transmits just a little visible light, while 403 is
> visually black. They are expensive, unfortunately, around $35
> in the mid-40 to 52mm sizes. I imagine there's an equivalent
> Kodak Wratten gel for around $25 in 3x3 inch, though I don't
> have full Wratten specs to check. Once nice thing with gels is
For Hg arc, the Wratten 18A would probably be good. It blocks visible
light and transmits from 300-400nm which would include the 365nm spectral
line. Unfortunately, it also transmits IR, and it is glass.
James Wilkins
jw
Alan Shinn
>
> dann mann wrote:
> >
> > Cloudy days are actually my favorite. Just yesterday I exposed a 2x3
> > foot stencil at 9am. It totally obscured sunlight. About 10 minutes
> > total exposure. I prefer the early hours because there is less risk of
> > overexposure and loss of contact due to heat build-up. I have made
> > screenprinting stencils with my frame setup to face an open door during
> > a midsummer shower and the results were fantastic.
>
> UV light meter. I know visible light intensity varies greatly with
> there is that much change. I suspect UV would be even worse.
>
> Suppose we take some UV sensitive detector, find a low cost UV filter
> (rejects most visible light) and put it into some integrator op amp
> circuit. It could be calibrated on a sunny day. Then, on a cloudy day
> one could watch it until needle or display reaches that same number.
>
> Don Stauffer in Minneapolis
> home web site- http://home1.gte.net/stauffer/
> home email- stau...@gte.net
> work email- stau...@htc.honeywell.com
--
(Carefully) bust a flourescent blacklight bulb and wash off the
phosphors etc. This stuff leaks near IR unfortunately (which silicon
photodetectors love) so you either need a detector that won't "see" IR
or you could have the filtered UV exite a flourescent paint and watch
that with a detector. I once had a detector (commercially made) that
was something like a cadmium sulphide sort of photoconductive detector
with a visable phosphore encapsulted with it. The cad sulphide could
"see" neither UV or IR and the phosphore could only "see" UV/Blue so it
was a good system. So-- the proposal is to use the blacklight bulb glass
to cut out the visable and then let the UV/IR shine onto a Cad Sulphide
cell (Radio Shack) that has a very thin layer of dayglo dye or paint
(highliter?). So there, about $8.00 for an infinite amount of black
light filter, $2.00 for a pack of photocells, and $1.00 for a highliter,
then just use an ohmeter to read it. Email me if you want to try this as
I already have the infinite amount of black light filter glass haveing
just had a UV instrument consulting job.
Looking forward:
Alan Shinn
Experience the
beginnings of microscopy.
Make or buy your own replica
of one of Antony van Leeuwenhoek's microscopes.
visit http://www.sirius.com/~alshinn/
Randy Gordon-Gilmore
exposure time of the photoresist? If so, functionally the best way is to
laminate a small test piece, and expose it using a Stauffer step wedge as the
artwork, develop and then adjust the exposure for your workpieces. The resist
has its own sensitivity to UV versus wavelength, and for a radiometer you'd
have to match that spectral curve pretty closely to obtain a useful number.
Morton's "Laminar Training Manual" summarizes:
"RECOMMENDATIONS FOR EXPOSURE CONTROL
Step tablets are useful tools to monitor the exposure and development or verify
overall process control. A radiometer allows a convenient measurement of
exposure energy quickly and frequently. The following procedure should be used
for complete control of the process and utilization of both tools:
1. Use a radiometer dialy to monitor the UV light source. Record the value
daily.
2. Use a radiometer with the artwork of each order to set the approximate
exposure.
3. It is recommended that step tablets be tested for each order, and each set
of artwork for each order."
So even with industrial-quality radiometers, step tablets are used as the
functional and final exposure control. A Stauffer 21-step wedge should be less
than $20 (mine was ~$13 a few years ago), and give 1/2 f-stop resolution in
exposure under the immediate exposure conditions, whether sunlight or
artificial light.
Don Foreman
Before we get too carried away, probably should verify that silicon
responds to UV. I'd sure think it would, unless the package blocks it.
I'll see if I can find a source for purple-peeper cells; they probably
aren't cheap either, but they wouldn't need any filtering. I expect that
they provide a current linearly proportional to incident UV, require a
high-impedance amplifier. Maybe a FET-input opamp buffer, followed by the
integrator. LF347, coupla bux from Digi-Key.
If the integration time is long enough that drift becomes a problem, adding
a comparator or even a 555 to "dump" a shorter timeconstant integrator
when it reaches a certain level would give a digital output -- pulses that
you could accumulate with a digital counter.
Ken Mayer
: Any sources for these -- Wratten 18A, B+W 403, maybe IR-blocking material?
Try B&H Photo in NYC. There are only 2 honest camera dealers in the city,
and this is one of them. www.bhphotovideo.com
: Before we get too carried away, probably should verify that silicon
: responds to UV. I'd sure think it would, unless the package blocks it.
The photon energy has to be high enough to kick the electrons into the
conduction band. I think the doping level might change its sensitivity to
various parts of the spectrum. (It's been 12 years since I studied the
topic)
: I'll see if I can find a source for purple-peeper cells; they probably
: aren't cheap either, but they wouldn't need any filtering. I expect that
: they provide a current linearly proportional to incident UV, require a
: high-impedance amplifier. Maybe a FET-input opamp buffer, followed by the
: integrator. LF347, coupla bux from Digi-Key.
: If the integration time is long enough that drift becomes a problem, adding
: a comparator or even a 555 to "dump" a shorter timeconstant integrator
: when it reaches a certain level would give a digital output -- pulses that
: you could accumulate with a digital counter.
--
Ken
:-)
Alan Shinn
>
> Any sources for these -- Wratten 18A, B+W 403, maybe IR-blocking material?
>
> responds to UV. I'd sure think it would, unless the package blocks it.
> aren't cheap either, but they wouldn't need any filtering. I expect that
> they provide a current linearly proportional to incident UV, require a
> high-impedance amplifier. Maybe a FET-input opamp buffer, followed by the
> integrator. LF347, coupla bux from Digi-Key.
>
> If the integration time is long enough that drift becomes a problem, adding
> a comparator or even a 555 to "dump" a shorter timeconstant integrator
> when it reaches a certain level would give a digital output -- pulses that
> you could accumulate with a digital counter.
--
Silicon does respond to UV but falls off rapidly below 400nm unless
specially configured and even then has little response below 350nm. Now,
at first glance, that should not be a problem since we are by nature
talking about pretty intense UV sources so ANY response should be good
enough. The problem being that silicon really loves near IR which is
abundant in sunlight and many other sources and being that the near IR
is hard to block.
The potential problem with purple peepers (an item that I never heard of
till this thread so I am not sure of it) and other UV flame detectors
like the UVtron by Hamamatsu is that they are solar blind detectors,
which is to say that they do not respond to long wave UV such as found
in sunlight or blacklight tubes. They probably "see" 254nm mercury
emmision just fine. I wonder if the usual photo mask materials transmit
in that region though?? Glass does not.
Spehro Pefhany
> The potential problem with purple peepers (an item that I never heard of
> till this thread so I am not sure of it) and other UV flame detectors
> like the UVtron by Hamamatsu is that they are solar blind detectors,
Some specs are at: http://www.hpk.co.jp/products/ETD/UVtronE.htm
They say response is 185-260nm. They give sensitivity in terms of "cpm",
which I interpret as "counts per minute", but I could be wrong! Dark is
10cpm max, illuminated is 5000cpm typ (based on 200nm light at 10pW/cm^2)
I assume the tube would be used an RC circuit relaxation oscillator and
would give a nice digital signal to be counted for the integration.
> which is to say that they do not respond to long wave UV such as found
> in sunlight or blacklight tubes. They probably "see" 254nm mercury
> emmision just fine. I wonder if the usual photo mask materials transmit
> in that region though?? Glass does not.
Both the sun and Hg lamps should have stable spectrums (we hope!) so a
measurement that rejects room lighting should work. Are you sure they are
"solar blind"? that doesn't make much sense to me.
Any idea how much these things cost? I'll e-mail Hammamatsu and see if
they answer.
Alan Shinn
>
> Both the sun and Hg lamps should have stable spectrums (we hope!) so a
> measurement that rejects room lighting should work. Are you sure they are
> "solar blind"? that doesn't make much sense to me.
>
> Any idea how much these things cost? I'll e-mail Hammamatsu and see if
> they answer.
>
> --
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Spehro Pefhany "The Journey is the reward"
> sp...@interlog.com
> Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
--
There is no 260nm energy in terestrial sunlight, it's stopped by the
atmosphere. That's why the UVtron is solar blind. Do let us know what
you find out about availability and price though. They have a very high
work function cathode like tungsten or such and thus need high energy
photons to kick out photoelectrons.
Spehro Pefhany
> There is no 260nm energy in terestrial sunlight, it's stopped by the
> atmosphere. That's why the UVtron is solar blind. Do let us know what
Interesting. So tanning involves longer wavelengths, then.
> you find out about availability and price though.
$37.13 each, 1-9 , minimum $50 order F.O.B. New Jersey, 1 week lead time.
Alan Shinn
>
>
> Sorry I was late entering this thread - but I am sure that somebody
> must make UV sensitive photodiodes. All that is really needed is to
> package the diode with a supersil (pure quartz) or sapphire window
> and it will have some response in the UV.
>
> If anyone wants I could look up some manufacturers at work.
>
> Jim
--
The problem (once you do get sensitivity to the desired wavelengths) is
to prevent the detector from "seeing" the visible and near IR.
mull...@advinc.com
Spehro Pefhany <sp...@interlog.com> wrote:
> Alan Shinn <als...@sirius.com> wrote:
> > There is no 260nm energy in terestrial sunlight, it's stopped by the
> > atmosphere. That's why the UVtron is solar blind. Do let us know what
>
> Interesting. So tanning involves longer wavelengths, then.
>
> > you find out about availability and price though.
>
> $37.13 each, 1-9 , minimum $50 order F.O.B. New Jersey, 1 week lead time.
>
Sorry I was late entering this thread - but I am sure that somebody
must make UV sensitive photodiodes. All that is really needed is to
package the diode with a supersil (pure quartz) or sapphire window
and it will have some response in the UV.
If anyone wants I could look up some manufacturers at work.
Jim
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Martin H. Eastburn
sensors are UV sensitive. Perhaps other photo-transistor devices
are. I know Radio-Shack used - used to sell a red plastic 'lens'
on a TO-3 diamond package. With the red - it uses IR and red.
Maybe they have something else. - check if possible the spectrial
responce curve. You don't have to have a peak in UV - just a
reasonable detection level. Then amplify the signal...
Jon Elson
Alan Shinn wrote:
> Don Foreman wrote:
> >
> > Any sources for these -- Wratten 18A, B+W 403, maybe IR-blocking material?
> >
> --
> Silicon does respond to UV but falls off rapidly below 400nm unless
> specially configured and even then has little response below 350nm. Now,
> at first glance, that should not be a problem since we are by nature
> talking about pretty intense UV sources so ANY response should be good
> enough. The problem being that silicon really loves near IR which is
> abundant in sunlight and many other sources and being that the near IR
> is hard to block.
>
The photo resist materials are most sensitive to 357 and 405 nM radiation.
These are some of the strong Mercury emmision lines. 253 nM is one of
the strongest lines, but it is getting into vacuum UV, so even a few mm of air
will absorb it. The lamp, exposure frame, film backing and the carrier sheet
on the resist will all absorb that short wavelength pretty severely. Also, if
there were some 253 nM light getting out of your lamp, it would be REALLY
dangerous, too. Some lamps use the 253 nM light internally to excite
phosphors on the inside of the glass to convert it to a longer wavelength,
such as roughly the 350 nM band, or roughly 400 nM band, according
to purpose.
There definitely are silicon photodiodes optimized for UV sensitivity.
It takes not only package changes (such as quartz, or even no window)
and selection of the front metallization and passivation to minimize
UV absorption. But, the UV intended for erasing EPROMS and
exposing photoresist is so intense, that any commercial grade
silicon photodiode should perform well with any lamp source
other than incandescent (halogen or not) where the IR is quite
substantial. Fluorescents don't emit much IR, and Hg arc lamps
emit so much more UV than near IR that it still will make little
difference.
Jon
Bill Newcomb
Jon Elson <jme...@artsci.wustl.edu> wrote:
>The photo resist materials are most sensitive to 357 and 405 nM radiation.
>These are some of the strong Mercury emmision lines. 253 nM is one of
>the strongest lines, but it is getting into vacuum UV, so even a few mm of air
>will absorb it. The lamp, exposure frame, film backing and the carrier sheet
Eh? Then why does my spectrometer (which is filled with air, and has a
pathlength of easily over a foot) indicate 254 nm just fine? VUV
starts more like 190 nm.
I used to use a handheld 254 nm UV light in the lab to visualize
thin-layer chromatography plates. It's not a good idea to stare at the
thing, but it won't instantly burn or blind you.
>There definitely are silicon photodiodes optimized for UV sensitivity.
>It takes not only package changes (such as quartz, or even no window)
>and selection of the front metallization and passivation to minimize
>UV absorption. But, the UV intended for erasing EPROMS and
>exposing photoresist is so intense, that any commercial grade
>silicon photodiode should perform well with any lamp source
>other than incandescent (halogen or not) where the IR is quite
>substantial. Fluorescents don't emit much IR, and Hg arc lamps
>emit so much more UV than near IR that it still will make little
>difference.
>
>Jon
>
--
nu...@best.com | "Computers like you to treat them as if they can do
| something other than display naked pix." -K.
mull...@advinc.com
nu...@best.com (Bill Newcomb) wrote:
> In article <35EAF8A4...@artsci.wustl.edu>,
> Jon Elson <jme...@artsci.wustl.edu> wrote:
>
> >The photo resist materials are most sensitive to 357 and 405 nM radiation.
> >These are some of the strong Mercury emmision lines. 253 nM is one of
> >the strongest lines, but it is getting into vacuum UV, so even a few mm of
air
> >will absorb it. The lamp, exposure frame, film backing and the carrier sheet
>
> Eh? Then why does my spectrometer (which is filled with air, and has a
> pathlength of easily over a foot) indicate 254 nm just fine? VUV
> starts more like 190 nm.
>
Hmm. Quite right. THe SPEX flurolog I used to used worked just fine
at 245nm. And the path was way far over a foot - had a double monochromator
on the input side. But is was really full of air (well, N2, we had
a purge on it to keep the ozone from the xenon lamp from eating the
gratings and mirrors.
Commercial fluorescent lamps do indeed run on the 254 from the
mercury vapor discharge.
Boy that hp xenon lamp really was a doozy, thought. Every time
we had to align it we had to wear welder's helmets, sunscreen, lab coats
and gloves. *Really* broad spectrum, intense light.
Jon Elson
> Boy that hp xenon lamp really was a doozy, thought. Every time
> we had to align it we had to wear welder's helmets, sunscreen, lab coats
> and gloves. *Really* broad spectrum, intense light.
>
I built a lamp to illuminate a fiber bundle that exposed blue-sensitive film
placed on a pen plotter. There was a lens assembly in place of the
plotter's pen, and a shutter made from a loudspeaker voice coil connected
to the pen raise/lower solenoid. The lamp was a 200 W Hg-Xe
Ozone-producing lamp. I tried to do the optical alignment of the
ellipsoidal mirror, heat splitter and shutter using the actual lamp, and lots
of protective gear. I didn't blind myself, but I got a hell of a sunburn
on exposed parts like my forehead and forearms. Never did get
it aligned that way. I finally made a lamp simulator, with a grain of
wheat lamp mounted on a rod in the exact position of the arc
relative to it's mounting post. With this rig, I only had one adjustment
that had to be done with the real lamp, which was sliding the lamp
mounting post up and down to peak the output (like focussing).
The Ozone this thing produced would drive you out of the room
in less than one minute. This thing threw out about 100 W of
253 nM light, most of which didn't go very far, even though the
fiber bundle was Quartz.
Jon
mull...@advinc.com
Yup, sounds familiar. Our setup had a big exhaust drop that ran all
the time to pull the ozone out of the enclosure.
Even with a "quartz" bundle you probably *didn't* get much throughput.
Most commercial grade quartz has a lot of OHs in it that absorb
heavilly, right around 254. If you want to put that thru a window
or a fiber it has to be a suprasil grade quartz. There's even
a company that puts out special UV grade fibers now - I think it
is Fiberguide industries that we dealt with.
Hope you got over that sunburn!
Regards, Jim