[sci.electronics] Infrared light source

sara@ajpo.sei.cmu.edu (Sara Moss) (02/04/88)

Does anyone know what combination of gases would provide a good
infrared light source in the range of 700 - 1100 nanometers?  The
intended use of the gas would be in a neon-type tube to provide a
continuous, diffused light source.

Alternatively, does anyone know of any continuous infrared light
source that provides:  diffused light, can be in a bendable, yet rigid
form up to 5 feet long, does not get hot (~ 5 watts would be nice), no
power cycling, and has a good long life span (like a few years).

I know, that is probably asking alot.  If any of those details do not
make perfect sense, it is probably due to my bad interpretation of the
requirements.  I am looking for this information for a friend.

jbn@glacier.STANFORD.EDU (John B. Nagle) (02/05/88)

      Mixing gases in "neon" tubes generally doesn't work.  The one
with the lowest breakdown voltage fires first and takes all the load.

					John Nagle

mcdonald@uxe.cso.uiuc.edu (02/06/88)

>Does anyone know what combination of gases would provide a good
>infrared light source in the range of 700 - 1100 nanometers?  The
>intend
>ed use of the gas would be in a neon-type tube to provide a
>continuous, diffused light source.

Krypton, at moderate to high pressures.

>Alternatively, does anyone know of any continuous infrared light
>source that provides:  diffused light, can be in a bendable, yet rigid
>form up to 5 feet long, does not get hot (~ 5 watts would be nice), no
>power cycling, and has a good long life span (like a few years).

An ordinary fluorescent light with a special near IR phosphor would
do fine. I have no idea whether such phosphors are commercially available.
Alternatively, a 2500 Angstrom UV(blacklight) tube could be used to
illuminate the appropriate phosphor externally.

You could also use a huge array of standard near ir LED's. This is
probably the easiest for 5 watts power input (not output).

dennisg@felix.UUCP (Dennis Griesser) (02/09/88)

In article <17298@glacier.STANFORD.EDU> jbn@glacier.UUCP (John B. Nagle) writes:
>      Mixing gases in "neon" tubes generally doesn't work.  The one
>with the lowest breakdown voltage fires first and takes all the load.

Well, kinda.

When I fiddle with my plasma sphere, I get two colors out of it.  The main
bolts are bluish.  The surface of the inner electrode and the inside of the 
sphere where your hand makes contact is pink.

I believe that there two gasses with different breakdown voltages.  Different
gasses glow in different areas due to differing charge densities at the
electrodes and in space.

Does anyone have a better theory?