Question about ir led's...

[triathlonluvr@aol.com]

A debate at work prompts this question.

We have a cluster pack of ir leds that transmit to a circuit card, that
receives light signal.

Question.... We have only just started replacing them when signal on
circuit card makes them suspect of generating a weak signal. I have
noticed when taking the old cluster of leds out, the led lens is a pink
hue of color. The replacement clusters led lens is clear.

I think that since these are powered on all day, for years at a time,
the ir changes the plastics color. Others think they were a pinkish
hue to begin with, and new ones are just clear.

Anyone familiar with this? Can the light generated from the led, which
is a red color, change the color of the plastic over an extended period
of time?

Thank you.

Jay

 

Yes, I believe you're on the right track. Several years ago, I worked
for a firm which made IR scanning devices for touch-screen VDUs.
Failing IR transmitters were the bane of our lives; many units were
returned after usage ranging from several months to a few years,
because of low IR emission.
IR receiver transistors can suffer from poor sensitivity.
I used to do comparative tests on both transmitters and receivers prior
to installation.

 

[redbelly]

triathlonluvr@aol.com wrote:

Can the light generated from the led, which
is a red color, change the color of the plastic over an extended period
of time?

Thank you.

Jay

Very doubtful. It usually requires uv to degrade plastics (i.e., cause
discoloration or turning them brittle). If the color has changed, the
IR had nothing to do with it.

Mark

 

[triathlonluvr@aol.com]

Okay... Thank you for your replies..

Jay