Searching \ for '[OT] Sending light down a pipe' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=sending+light+down
Search entire site for: 'Sending light down a pipe'.

Exact match. Not showing close matches.
PICList Thread
'[OT] Sending light down a pipe'
2000\05\16@123907 by Harold M Hallikainen

picon face
       Severely off topic, but I wanted to tap this group of experts...  I have
a client who is trying to send light from an incandescent lamp (about
250W) down a "light pipe." The light pipe appears to be like a fiber
optic pipe, but is a fairly large diameter and is, I believe, fluid
filled.
       Attempts thus far have been based on using a lamp with a built in
reflector (a projector lamp) and putting lenses in front of it. I have a
feeling that a lot of light is still missing the pipe.
       Is anyone aware of a "light capturer" that captures light from a source
and sends it down a light pipe?

Harold



FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
dl.http://www.juno.com/get/tagj.

2000\05\16@124739 by Quitt, Walter

flavicon
face
www.moritexusa.com

Fiber Optic Illumination Systems
We use their equipment in our machines

http://www.microjoin.com

GL,
Walt...

{Original Message removed}

2000\05\16@125739 by Dale Botkin

flavicon
face
On Tue, 16 May 2000, Harold M Hallikainen wrote:

>         Severely off topic, but I wanted to tap this group of experts...  I have
> a client who is trying to send light from an incandescent lamp (about
> 250W) down a "light pipe." The light pipe appears to be like a fiber
> optic pipe, but is a fairly large diameter and is, I believe, fluid
> filled.
>         Attempts thus far have been based on using a lamp with a built in
> reflector (a projector lamp) and putting lenses in front of it. I have a
> feeling that a lot of light is still missing the pipe.
>         Is anyone aware of a "light capturer" that captures light from a source
> and sends it down a light pipe?

For more years than I care to think about, I serviced IBM 3420 and similar
tape drives.  They used light pipes, which were bundles of optical fibers
approximately 1/16" or so in diameter.  They used a high-intensity lamp
similar to a brake light (24V if I recall correctly) with a Bakelite
manifold that simply pointed the ends of the light pipes straight at the
filament.

This was used to provide light to sensors that used phototransistors and
photodiodes for various tachometers used in the tape drives.

Now that I've remembered that, I need to go wash down a handful of Valium
with a bottle of cheap bourbon...  <shudder>

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
               -- Isaac Asimov

2000\05\16@125954 by Thomas C. Sefranek

face picon face
Harold M Hallikainen wrote:

>         Severely off topic, but I wanted to tap this group of experts...  I have
> a client who is trying to send light from an incandescent lamp (about
> 250W) down a "light pipe." The light pipe appears to be like a fiber
> optic pipe, but is a fairly large diameter and is, I believe, fluid
> filled.
>         Attempts thus far have been based on using a lamp with a built in
> reflector (a projector lamp) and putting lenses in front of it. I have a
> feeling that a lot of light is still missing the pipe.
>         Is anyone aware of a "light capturer" that captures light from a source
> and sends it down a light pipe?

The problem is that the light pipe, (Lucite) only accepts light from a limited set
of angles.
You need to collimate the light to get it to enter the light pipe.
There are compound lenses that can do this somewhat.
There is a limit to how much of the total light (from an isotropic source)
you can capture and collimate.

{Quote hidden}

--
 *
 |  __O    Thomas C. Sefranek  spam_OUTtcsTakeThisOuTspamcmcorp.com
 |_-\<,_   Amateur Radio Operator: WA1RHP
 (*)/ (*)  Bicycle mobile on 145.41, 448.625 MHz

ARRL Instructor, Technical Specialist, VE Contact.
hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org

2000\05\16@130405 by Quitt, Walter

flavicon
face
Yet another source (saw in our lab:)
http://www.scienscope.com

-----Original Message-----
From: Dale Botkin [.....daleKILLspamspam@spam@BOTKIN.ORG]
Sent: Tuesday, May 16, 2000 9:56 AM
To: PICLISTspamKILLspamMITVMA.MIT.EDU
Subject: Re: [OT] Sending light down a pipe


On Tue, 16 May 2000, Harold M Hallikainen wrote:

>         Severely off topic, but I wanted to tap this group of experts...
I have
> a client who is trying to send light from an incandescent lamp (about
> 250W) down a "light pipe." The light pipe appears to be like a fiber
> optic pipe, but is a fairly large diameter and is, I believe, fluid
> filled.
>         Attempts thus far have been based on using a lamp with a built in
> reflector (a projector lamp) and putting lenses in front of it. I have a
> feeling that a lot of light is still missing the pipe.
>         Is anyone aware of a "light capturer" that captures light from a
source
> and sends it down a light pipe?

For more years than I care to think about, I serviced IBM 3420 and similar
tape drives.  They used light pipes, which were bundles of optical fibers
approximately 1/16" or so in diameter.  They used a high-intensity lamp
similar to a brake light (24V if I recall correctly) with a Bakelite
manifold that simply pointed the ends of the light pipes straight at the
filament.

This was used to provide light to sensors that used phototransistors and
photodiodes for various tachometers used in the tape drives.

Now that I've remembered that, I need to go wash down a handful of Valium
with a bottle of cheap bourbon...  <shudder>

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
               -- Isaac Asimov

2000\05\16@140850 by M. Adam Davis

flavicon
face
A big part of it, as noted by others, is getting the light collimated using a
parabolic reflector and a lens.  Your best bet for this route is to buy a lamp
which allready does this (look for theater lighting - expensive bulbs with
reflectors and lenses built it).

Another way to work it (less efficient, but gets the job done) is to make a
shiny (insert favorite metal here - say aluminum flashing) box or shroud which
completely covers the light and the end of the light pipe.  The light has
nowhere to go except into the pipe (a little is absorbed by the shroud depending
on it's reflectivity), and anything at the wrong angle will simply bounce around
until it is at a good angle and enters the light pipe.  Be careful of heat build
up though, you'll need vents/fans depending on the efficiency of the bulb.  Of
course, light exiting the light pipe will not be collimated, it would come out
at all the angles the light came it at.

-Adam

Harold M Hallikainen wrote:
{Quote hidden}

2000\05\16@163534 by Robert A. LaBudde

flavicon
face
<x-flowed>At 09:36 AM 5/16/00 -0700, Harold wrote:
>         Severely off topic, but I wanted to tap this group of
> experts...  I have
>a client who is trying to send light from an incandescent lamp (about
>250W) down a "light pipe." The light pipe appears to be like a fiber
>optic pipe, but is a fairly large diameter and is, I believe, fluid
>filled.
>         Attempts thus far have been based on using a lamp with a built in
>reflector (a projector lamp) and putting lenses in front of it. I have a
>feeling that a lot of light is still missing the pipe.
>         Is anyone aware of a "light capturer" that captures light from a
> source
>and sends it down a light pipe?

1. Focus the light from the lamp.
2. Add a collimating lens to generate parallel rays with the same aperture
as the pipe.

The light capture is dependent on effectiveness of the parabolic reflector
and the capture aperture of the first (focusing) lens. You will also lose
about 4% reflection at each lens boundary.

================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: .....ralKILLspamspam.....lcfltd.com
Least Cost Formulations, Ltd.                   URL: http://lcfltd.com/
824 Timberlake Drive                            Tel: 757-467-0954
Virginia Beach, VA 23464-3239                   Fax: 757-467-2947

"Vere scire est per causas scire"
================================================================

</x-flowed>

2000\05\16@184714 by rottosen

flavicon
face
When you get *too* much light focused onto the end of the light pipe you
have to worry about melting the fibers. An IR blocking glass plate or
lens in combination with a IR reflecting mirror may be needed with very
high intensity light sources.

-- Rich



"M. Adam Davis" wrote:
{Quote hidden}

2000\05\17@095239 by paulb

flavicon
face
Harold wrote:

> I have a client who is trying to send light from an incandescent lamp
> (about >250W) down a "light pipe." ... Attempts thus far have been
> based on using a lamp with a built in reflector (a projector lamp) and
> putting lenses in front of it. I have a feeling that a lot of light is
> still missing the pipe.

 Nevertheless that is the only really practical way to do it.

 Integral mirror projector lamps (as with separate mirror assemblies)
take the light from the back of the filament and focus it into an image
which appears exactly adjacent to and abutting the actual filament (or
arc).

 As the filament is generally (coiled and) longer than it is wide, this
makes it appear twice as efficient as it would otherwise be, and more
nearly square in shape.  If the mirror is not precisely aligned, it
could focus the image back on the filament itself which would be
useless.

 Now, the task of the front lens is neither more nor less than to focus
an image of the filament onto your light-pipe input aperture.  Certain
principles of optics apply; each aperture must be in proportion to its
distance from the lens so that the image on the light-pipe exactly fills
its aperture.

 The lens needs as large an aperture (or as small an "F" stop, being
the ratio of focal length to lens diameter) as possible to intercept the
widest cone of light from the filament.

 This is limited by the practicalities of proximity to the filament
(ventilation, heat resistance of lens and coatings, and the presence of
the bulb envelope!), and also the capture angle of the light-pipe as was
mentioned.  The relative aperture of filament and light-pipe are not
that dissimilar, so meniscus lenses with favourable apertures cannot be
used.

 If all these factors have already been considered, then you are most
unlikely to do better.  It should at least be possible to arrange for
almost all of the light intercepted by the lens to enter the pipe.
--
 Cheers,
       Paul B.

2000\05\17@125430 by David Duley

flavicon
face
On Tue, 16 May 2000 09:36:14 -0700, you wrote:

>        Severely off topic, but I wanted to tap this group of experts...  I have
>a client who is trying to send light from an incandescent lamp (about
>250W) down a "light pipe." The light pipe appears to be like a fiber
>optic pipe, but is a fairly large diameter and is, I believe, fluid
>filled.
>        Attempts thus far have been based on using a lamp with a built in
>reflector (a projector lamp) and putting lenses in front of it. I have a
>feeling that a lot of light is still missing the pipe.
>        Is anyone aware of a "light capturer" that captures light from a source
>and sends it down a light pipe?
>
>Harold
>
>

Hi Harold and all,

Check out http://www.lumitex.com  We use large custom versions of their woven
optical fiber mats for an explosion proof inspection light.  They sell
the fiber bundles and light sources.  The source we use is a 150W
halogen projection bulb in a special socket with an IR filter. They
have pre made light sources as well.

Best regards

Dave Duley
http://www.dreitek.com

2000\05\19@171034 by Martin McCormick

flavicon
face
       As an AV technician, I worked on a lot of Kodak Carrousel
slide projectors.  The illumination of the slide is fairly similar
to what needs to be done to concentrate light in to the pipe.

       The older Carrosels had a lamp that used to remind me of
a radio tube.  The filament was actually several parallel coils
of wire in front of a reflector that directed the light in the
general direction of the optics and away from the stuff that
would melt in a heartbeat were it exposed to that little Sun in a
box.

       The optics consisted of three lenses.  The one closest to
the bulb is a heat lens and has no refractive properties, but
which absorbs infrared light.  Without it, slides melt to a
blistered mess in seconds, (no kidding), and with it, they can
stay in the gate for an indefinite time.

       The other two lenses are called "condenser" lenses and
are double convex like a magnifying glass lens.  They broadly
focus the lamp in to a wide beam that covers the rear surface of
the slide.  The only other lens is the one which you see aimed
at the screen.

       One could imagine the light pipe in about the same spot
as the slide.

       The newer Carrousels have a bulb that looks exactly like
a flashlight lamp except that the bulb and reflector are one
costly and short-lived module.  It shines at right angles to the
optics, but there is a front-surfaced mirror at a 45 degree angle
between the lamp reflector and the optics which creates the light
path.  The first lens, again, is the heat lens which is the
same heat lens as is used in all Carrousels pub there is only
one condenser lens to make the broad beam.

       You will probably need the heat lens to keep from
melting the pipe as someone already mentioned.  If you use
recycled parts, be very careful of the heat lens.  New heat
lenses are quite sturdy, about 8 millimeters or 1/4 inch thick.
After use, they still look just as sturdy, but they get heat
stressed.  They have a nasty habit of violently shattering at
some random time after being released from the clamp that holds
them in place.  The glass flies everywhere and usually stays in
big pieces, but big sharp ones.  If one goes off in your hand,
the sensation is like having a big spring released.

       If it goes off near your eye while you inspect it, you
may need to learn Braille to stay literate.

Martin McCormick WB5AGZ  Stillwater, OK
OSU Center for Computing and Information Services Data Communications Group

2000\05\20@093353 by paulb

flavicon
face
Martin McCormick wrote:

> The filament was actually several parallel coils of wire in front of a
> reflector that directed the light in the general direction of the
> optics and away from the stuff that would melt in a heartbeat were it
> exposed to that little Sun in a box.

 Many (older) projectors are provided with a "pinhole" slide
(cardboard) which permits adjustment of a mirror.  My previous post
mentioned the correct alignment of the mirror for a single-coil
filament; the corresponding procedure for a multi-coil filament is to
adjust so that the reflected image of the coils is aligned exactly
between the direct image; again so that together the light source
appears as a single uniform square.

>   The other two lenses are called "condenser" lenses and are double
> convex like a magnifying glass lens.

 Or plano-convex x 2.

>  They broadly focus the lamp in to a wide beam that covers the rear
> surface of the slide.

 The condenser lenses are adjusted to project an image of the filament
well beyond the slide itself.  In general, they project the filament
image inside the objective lens so that as much light as possible is
used effectively.

 An excellent example of this is the overhead projector whose
efficiency critically depends on focussing the beam onto the objective
lens - that is what the huge Fresnel condenser does.  Of course, this
is made difficult by the fact that the objective lens actually moves to
focus the image of the slide.

>   One could imagine the light pipe in about the same spot as the
> slide.

 No.  For a light pipe, you have only one condenser lens (may however
be compound) and it focusses the light on the entry aperture of the
light pipe.  The objective (of the design, not lens!) is to focus on a
quite *small* aperture compared to a slide projector where uniform
illumination of a *large* slide is required.  Even 8mm projectors!

>   The newer Carousels have a bulb that looks exactly like a
> flashlight lamp except that the bulb and reflector are one costly and
> short-lived module.

 With the reflector pre-focussed.  At one lecture I recently attended,
I arrived late (*not* unusual, really).  In my absence, it appears they
had successively consumed *five* bulbs trying to get one projector to
operate before they ran out of bulbs.  I presume the late model machine
has a SMPS and this one had a regulator malfunction.

>   You will probably need the heat lens to keep from melting the pipe
> as someone already mentioned.

 Presumably - *although* - glass pipes should not melt as they should
transmit heat instead of absorbing it.  But in general, the intention to
these units is usually to provide a cold light source.

<RACONTAGE>
 Inservice training on these sources is often a bit slack.  I got
*very* stroppy with a nursing sister this week who wanted to switch the
light source off during a part of a procedure where the "scope" was -
temporarily - out of use.

 She was concerned about it setting fire to the white "sponge" in which
I had wrapped it.  She later said it had happened once with a green one;
I pointed out it was unlikely with a clean white one and has certainly
never happened to me in the past ten years.

 My concern was with the ever present risk on turning off the light
source that it may not start the next time.  In the middle of a
half-finished procedure, that *really* puts a spanner in the works, even
more so than the odd charred sponge.
</RACONTAGE>
--
 Cheers,
       Paul B.

2000\05\20@201309 by rottosen

flavicon
face
"Paul B. Webster VK2BZC" wrote:

>>> snip >>>

>   Presumably - *although* - glass pipes should not melt as they should
> transmit heat instead of absorbing it.  But in general, the intention to
> these units is usually to provide a cold light source.


This is true. However, the light sources that I worked with *could* burn
wood at the focal point at the end of the light pipe. The lamps in these
light sources were rated at several hundred watts.


{Quote hidden}

I think some explanation is needed here. The reason the lamp might not
restart is that it is a xenon lamp. (You can imagine these lamps as huge
neon panel lamps).

They have a minimum voltage required to ionize the gas. Once the gas is
ionized, the lamp will continue to operate. While the lamp is being
used, the firing voltage degrades and can increase above the voltage
supplied by the starting circuit. Since the lamp is on it can continue
to work. Turning the lamp off and then back on will now not work because
it will no no longer fire.

>  In the middle of a
> half-finished procedure, that *really* puts a spanner in the works, even
> more so than the odd charred sponge.
> </RACONTAGE>


I am sure the patient would complain more than the sponge  :-)


> --
>   Cheers,
>         Paul B.

More... (looser matching)
- Last day of these posts
- In 2000 , 2001 only
- Today
- New search...