Automotive HID Projector Lamp Exposing a PCB?

[D from BC]

I expose pcbs with a cheapo 500W halogen work lamp.
Exposure time ~30 minutes..

Could I reduce the exp time with an auto HID projector lamp? (Scrap
yard. BMWs I think. Who hasn't been blinded by those suckers.)

I see blue light from those HID lamps.
If there's more blue end, than perhaps there's more UV too?
It's probably not a big spectral span from blue to the UV band.

A point light source is supposed to be best for exposing circuit
boards..
A projector makes a nice spot.
UV tubes radiate radially.
I have no idea how this difference in directionally has on the
exposure quality.

Anybody seen a spectral graph for those automotive HID lamps?
I tried to Google up a spectrum.. Nothing yet.

Note: UV tubes are not easily found around here but I'm surrounded by
scrap yards..


D from BC

 

[[email protected]]

I expose pcbs with a cheapo 500W halogen work lamp.
Exposure time ~30 minutes..

Could I reduce the exp time with an auto HID projector lamp? (Scrap
yard. BMWs I think. Who hasn't been blinded by those suckers.)

I see blue light from those HID lamps.
If there's more blue end, than perhaps there's more UV too?
It's probably not a big spectral span from blue to the UV band.

A point light source is supposed to be best for exposing circuit
boards..
A projector makes a nice spot.
UV tubes radiate radially.
I have no idea how this difference in directionally has on the
exposure quality.

Anybody seen a spectral graph for those automotive HID lamps?
I tried to Google up a spectrum.. Nothing yet.

Note: UV tubes are not easily found around here but I'm surrounded by
scrap yards..

As far as I know, the HID stands for High Intensity Discharge - in
other words they are compact arc lamps.

The envelope is probably doped to block the hard ultra-violet
component.

Note that arc lamps are something of swine to drive - the slope
resistance tends to be slightly negative, so you need a releatively
high impedance source. On eof my old colleagues developed the drive
circuit that BMW used when they first introduced the lamps - if you
get the lamp from a junked top-end BMW, don't forget to get the drive
circuit at the same time.

 

[Tam/WB2TT]

I expose pcbs with a cheapo 500W halogen work lamp.
Exposure time ~30 minutes..

Could I reduce the exp time with an auto HID projector lamp? (Scrap
yard. BMWs I think. Who hasn't been blinded by those suckers.)

I see blue light from those HID lamps.
If there's more blue end, than perhaps there's more UV too?
It's probably not a big spectral span from blue to the UV band.

A point light source is supposed to be best for exposing circuit
boards..
A projector makes a nice spot.
UV tubes radiate radially.
I have no idea how this difference in directionally has on the
exposure quality.

Anybody seen a spectral graph for those automotive HID lamps?
I tried to Google up a spectrum.. Nothing yet.

Note: UV tubes are not easily found around here but I'm surrounded by
scrap yards..


D from BC

Philatelic supply houses sell UV lamps with a shade that sends most light
down. Some of them are even dual wavelength.

Tam

 

[John Larkin]

I expose pcbs with a cheapo 500W halogen work lamp.
Exposure time ~30 minutes..

Could I reduce the exp time with an auto HID projector lamp? (Scrap
yard. BMWs I think. Who hasn't been blinded by those suckers.)

I see blue light from those HID lamps.
If there's more blue end, than perhaps there's more UV too?
It's probably not a big spectral span from blue to the UV band.

A point light source is supposed to be best for exposing circuit
boards..
A projector makes a nice spot.
UV tubes radiate radially.
I have no idea how this difference in directionally has on the
exposure quality.

Anybody seen a spectral graph for those automotive HID lamps?
I tried to Google up a spectrum.. Nothing yet.

Note: UV tubes are not easily found around here but I'm surrounded by
scrap yards..


D from BC

I've used warehouse-type mercury vapor lamps to expose pcb's. A 175
watt lamp, about 3 feet above the board, is close to a point source
and exposes a KPR-coated board in 3-5 minutes. I removed the reflector
from the fixture, mounted it so that the tube is horizontal, and
silvered the top of the tube with a piece of aluminum foil, all of
which directs the light down and keeps the source size small. It casts
nice sharp shadows.

I don't understand why so many people want to make light boxes, which
have terrible optics. I guess they enjoy carpentry.

John

 

[D from BC]

As far as I know, the HID stands for High Intensity Discharge - in
other words they are compact arc lamps.

The envelope is probably doped to block the hard ultra-violet
component.

Note that arc lamps are something of swine to drive - the slope
resistance tends to be slightly negative, so you need a releatively
high impedance source. On eof my old colleagues developed the drive
circuit that BMW used when they first introduced the lamps - if you
get the lamp from a junked top-end BMW, don't forget to get the drive
circuit at the same time.

Hopefully the drive circuit is easy to pull out and is not buried
somewhere in the BMW.


D from BC

 

[D from BC]

I've used warehouse-type mercury vapor lamps to expose pcb's. A 175
watt lamp, about 3 feet above the board, is close to a point source
and exposes a KPR-coated board in 3-5 minutes. I removed the reflector
from the fixture, mounted it so that the tube is horizontal, and
silvered the top of the tube with a piece of aluminum foil, all of
which directs the light down and keeps the source size small. It casts
nice sharp shadows.

I don't understand why so many people want to make light boxes, which
have terrible optics. I guess they enjoy carpentry.

John

Speaking of light boxes...
I had the crazy idea of turning a school overhead projector into a
sort of light box. I think that would make a nice spot with low angle
light (coherent I think is the word).
The light source would be replaced with something with sufficient UV
such as halogen, mercury vapor or perhaps UV tubes..


D from BC

 

[[email protected]]

Speaking of light boxes...
I had the crazy idea of turning a school overhead projector into a
sort of light box. I think that would make a nice spot with low angle
light (coherent I think is the word).
Collimated.

The light source would be replaced with something with sufficient UV
such as halogen, mercury vapor or perhaps UV tubes..

D from BC

Dude, if you're from BC, you must have TONS of "botanical supply
stores" that sell UV gro-lamps.

 

[D from BC]

Dude, if you're from BC, you must have TONS of "botanical supply
stores" that sell UV gro-lamps.

They only sell gigantic pot lighting systems..
No small scale..
Just kidding...
I might check it out.. There's a shop just down the street.

I did a 10 second search to check my vocabulary on coherent light.
http://amasci.com/miscon/coherenc.html
"Coherent light comes from very small light sources."

The school projector optics would do the collimating to make near
coherent light..


D from BC

 

[John Larkin]

I did a 10 second search to check my vocabulary on coherent light.
http://amasci.com/miscon/coherenc.html
"Coherent light comes from very small light sources."

That web page is nonsense.

The school projector optics would do the collimating to make near
coherent light..

No, a thermal or conventional gaseous source, or an led, is
incoherent. Lasers make coherent light, but don't have to be very
small. NIF uses coherent lasers that are about the size of sewer
pipes.

John

 

[D from BC]

That web page is nonsense.


No, a thermal or conventional gaseous source, or an led, is
incoherent. Lasers make coherent light, but don't have to be very
small. NIF uses coherent lasers that are about the size of sewer
pipes.

John

Ahh...
Often I see the word 'coherent' used to describe laser light but not
for anything else.
So..what's a good word to describe the directivity of light?
1/2 intensity view angle?
I'm probably misusing the word coherent.
More or less coherent is probably like saying more or less black.
Or more or less true.


D from BC

 

[Brian]

I don't understand why so many people want to make light boxes, which
have terrible optics. I guess they enjoy carpentry.

John

I never understand why people etch boards rather than have them made. I
guess they like the chemicals

 

[John Larkin]

I never understand why people etch boards rather than have them made. I
guess they like the chemicals

I agree. You can get maybe 4 pieces of plated-through boards for about
$60.

Once you get FeCl under your fingernails, it pretty much has to grow
out.

John

 

[D from BC]

I never understand why people etch boards rather than have them made. I
guess they like the chemicals

I fk up a lot so I make my own boards.
And..
I get my boards made on weekends, holidays and late at night.
And..
I have my boards ready in about 1 hour.
Other DIY pcb makers are even faster. 10 minutes should be possible.
10 mil tracks..no problem.
Also..some homebrew etchants use cheap off the shelf chemicals without
using ammonium persulfate nor ferric chloride.
But, for quality, vias, multilayer,I'd go to a pcb fab house after
I've worked out the bugs with my own boards.


D from BC

 

[Fred Bartoli]

D from BC a écrit :

I fk up a lot so I make my own boards.
And..
I get my boards made on weekends, holidays and late at night.

Get a wife.

 

[Rich Grise]

I agree. You can get maybe 4 pieces of plated-through boards for about
$60.

Yabbut, to you, $60.00 is pocket change. And I only need one prototype,
which is probably going to get hacked anyway.

Once you get FeCl under your fingernails, it pretty much has to grow
out.

Idiot! You're not supposed to soak your hands in the stuff! ;-)

Cheers!
Rich

 

[Tam/WB2TT]

I fk up a lot so I make my own boards.
And..
I get my boards made on weekends, holidays and late at night.
And..
I have my boards ready in about 1 hour.
Other DIY pcb makers are even faster. 10 minutes should be possible.
10 mil tracks..no problem.
Also..some homebrew etchants use cheap off the shelf chemicals without
using ammonium persulfate nor ferric chloride.
But, for quality, vias, multilayer,I'd go to a pcb fab house after
I've worked out the bugs with my own boards.


D from BC

Some years ago people had success using sunlight. Claimed it worked better
than cheap lights. I have used EPROM erasers.

Tam

 

[John Larkin]

Ahh...
Often I see the word 'coherent' used to describe laser light but not
for anything else.
So..what's a good word to describe the directivity of light?
1/2 intensity view angle?
I'm probably misusing the word coherent.
More or less coherent is probably like saying more or less black.
Or more or less true.


D from BC

http://en.wikipedia.org/wiki/Collimated

http://en.wikipedia.org/wiki/Beam_divergence

http://en.wikipedia.org/wiki/Coherent_light#Spatial_coherence


John

 

[D from BC]

http://en.wikipedia.org/wiki/Collimated

http://en.wikipedia.org/wiki/Beam_divergence

http://en.wikipedia.org/wiki/Coherent_light#Spatial_coherence


John

In those links I also picked up 'angular spread' to add to my
collection of technical jargon..

Oops..coherence is an addition/subtraction/interference due to phase
difference.
Something I see in electronics. (Analog summing circuits.)

Ohhh...collimated or beam divergence are the proper terms..
"
To produce usefully collimated light, the light source must
approximate a point; that is, it must be small relative to the optical
system, like the image of the star formed by a mirror."

D from BC

 

[D from BC]

Some years ago people had success using sunlight. Claimed it worked better
than cheap lights. I have used EPROM erasers.

Tam

It rains here for about 4 to 6 months during the winter season.

D from BC

 

[Rich Grise]

It rains here for about 4 to 6 months during the winter season.

I've used sunlight in sunny southern California.

Just look for a "germicidal" fluorescent tube (and probably fixture)
at your local household goods shop.

I also have an EPROM eraser for sale. ;-)

Good Luck!
Rich