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jon_jon_phenomenon
hi

i am trying to make light up shapes, like a neon sign using acrylic
rod and some leds

its the bendy parts im not sure how to create

i was think of using transparent tubing and filling it with some clear
glue, though not sure what effect it will give, any ideas?

or should i be heating , casting something?

thanks
Uncle Al
Heat the acrylic above its Tg of 105 C, make your bends on a flat
surface, anneal above Tg and cool. If you bend it too near Tg and
incorporate internal strain you get eventual crazing. You want the
polymer to be relaxed.

The coupling of the LED to the rod is critical. Excavate a conformal
recess and use a thin layer of glue of intermediate refractive index
for maximum coupling.
Mark Thorson
Forrest Mims many years ago described how to make
optical fiber transceivers in an article in Popular Electronics
using a simple technique. Push the point of a soldering iron
right through the lens, until you just barely touch the die.
Then, put in a drop of glue, and insert the fiber through
the glue. It turns out that an LED can be used both as
a light source and a light sensor.

I've heard that this article caused tremendous problems
for AT&T a few years later when they were trying to
patent certain key features of their optical telephone.
Samu Aalto
I would remember one guy did it with heating up some saturated veggie oil
or paraffin in the kettle. He tempered the fluid first up to 110-120 C,
then immersed the acrylic pieces in the hot fluid and kept them there for
a short while. He had a jig to get the shape right.

For led joining (coupling), a well-wetting adhesive with right kind of
refractive index is important to get out most of it. Thin layer, so
there'll be less bubbles.
Entropyfoe
www.micalighting.com/fiber_optics.html

They have the products.
Gabrielle
QUOTE (Entropyfoe+Apr 17 2004, 09:31 PM)
www.micalighting.com/fiber_optics.html

They have the products.

The acrylic light pipe works well to illustrate internal reflection and how a fiber optic cable works. The product mentioned is awesome.thank you for posting.
Forrest M. Mims III
QUOTE (Mark Thorson+Apr 17 2004, 09:30 PM)
Forrest Mims many years ago described how to make
optical fiber transceivers in an article in Popular Electronics
using a simple technique.  Push the point of a soldering iron
right through the lens, until you just barely touch the die.
Then, put in a drop of glue, and insert the fiber through
the glue.  It turns out that an LED can be used both as
a light source and a light sensor.

I've heard that this article caused tremendous problems
for AT&T a few years later when they were trying to
patent certain key features of their optical telephone.

Mark Thorson is correct about my development of a 2-way communication system based on a single LED at each end of the link. I proposed this to Bell Labs, and they sent me an agreement that they would be in touch should they want to exploit the technology. A few years later, they announced this technology as their invention. They also filed for various patents on what was my invention. After making two trips to New Jersey to negotiate with them, they refused to honor their written agreement. The result was a lawsuit with a settlement in my favor. The story is told in my book "Siliconnections" (McGraw-Hill).

As for making a hole in an LED to receive an optical fiber, I don't recommend using a hot soldering iron. Instead, simply bore a hole into the top of an epoxy LED while using care to avoid the bonding lead that connects to the top of the chip. You can then insert the fiber with some appropriate cement.

Forrest M. Mims III
www.forrestmims.org
www.sunandsky.org
twitter.com/fmims
www.youtube.com/fmims
rpenner
Incredibly, I tend to believe the claims of the previous poster. It must a Christmas miracle.

We will be returning to my regular program of "Bah, humbug" as soon as technically possible.
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