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LED's in tubes?

K

Ken C

Jan 1, 1970
0
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.
 
J

John Fields

Jan 1, 1970
0
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube?
 
I

Impmon

Jan 1, 1970
0
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.

LED produces very little heat at rated specs so it should be fine.
 
A

Anthony Fremont

Jan 1, 1970
0
Ken C said:
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.

To be absolutely sure, you'll just have to test it out, but I think it
will be fine at normal room temps. A straw won't do much to keep the
light in, but fiber optic cable or a "litepipe" will do it easily.
Litepipes are solid plastic tubes that can move light around corners and
the like. I believe that digikey sells them.

As for the heat, I ran an RGB LED with a styrofoam peanut pushed over it
to act as a diffuser. After many hours, I didn't notice any difference
in the light output. I'm sure the wire leads of the LED did a better
job of removing heat than could possibly be dissipated thru the plastic
enclosure.
 
J

John Popelish

Jan 1, 1970
0
Ken said:
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.
Sure. An aluminum tube would be even better from opacity,
reflectivity and heat conductivity standpoints.
 
R

Rich Grise

Jan 1, 1970
0
Can I put a snug, thin, opaque plastic tube (like a straw) around the body
an LED to prevent the escape of light except out the end of the tube? The
tube will extend approximately 1/8" past the top of the LED. I am
concerned about heat buldup. The LED will be operated at normal spec --
20 ma.

Absolutely. I did exactly this with about 50 LEDs on a snazzy panel
some small company was building where I was a temp. They had this LED
panel mounted about 1/2" behind a sheet of transparent lexan with the
light pattern screened on the back, and you practically couldn't tell
which LED was lit, so I got some straws at the local fast food joint, cut
them into 1/2" pieces, and slipped them over the LEDs. Worked perfectly,
and they shipped the sucker and started ordering straws, and kept my jig!

Cheers!
Rich
 
R

Rodney

Jan 1, 1970
0
Ken C said:
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.

For a nice fit you can use heat shrink tubing if you are careful about how
you apply the heat. Black heat shrink is very opaque.
 
P

Pooh Bear

Jan 1, 1970
0
Ken said:
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.

So. What is it you *really* want to do ?

There are dedicated 'lightpipe leds' if that's your intention.

Graham
 
T

Terry

Jan 1, 1970
0
Ken C said:
Can I put a snug, thin, opaque plastic tube (like a straw) around the
body an LED to prevent the escape of light except out the end of the
tube? The tube will extend approximately 1/8" past the top of the
LED. I am concerned about heat buldup. The LED will be operated at
normal spec -- 20 ma.
20 ma at say 3 volts (maximum) ? That's 60 milliwatts, or one sixteenth of
one watt.
Not likely to burn the fingers or anything else!
 
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