Blue tinted IRLED.

[ian field]

Anyone know why some IRLEDs have a blue tinted encapsulation instead of
water clear?

TIA.

 

[Hal Murray]

Anyone know why some IRLEDs have a blue tinted encapsulation instead of
water clear?

Just a guess...

It's the same plastic they use on the receivers to filter out
visible light so they don't have to qualify and stock 2 types
of plastic.

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[ian field]

"Hal Murray" <hal-usenet@ip-64-139-1-69.sjc.megapath.net> wrote in message
news:bcqdnRg2g4Sds-PVnZ2dnUVZ_gWdnZ2d@megapath.net...

Anyone know why some IRLEDs have a blue tinted encapsulation instead of
water clear?

Just a guess...

It's the same plastic they use on the receivers to filter out
visible light so they don't have to qualify and stock 2 types
of plastic.

Blue tinted IR receivers seem to be relatively rare, by far the most common
these days is the integrated modules which look almost black in normal
incident light but are obviously transparent to IR radiation. But that
doesn't necessarily mean your guess is wrong.

 

[nospam]

"ian field" <dai.ode@ntlworld.com> wrote:

Anyone know why some IRLEDs have a blue tinted encapsulation instead of
water clear?

The blue might filter out the little bit of visible red you get from some
IR LEDS. Not sure why that would be seen as a benefit. Do you see any red
from them?

The blue tint is probably less lossy that the black you see on IR
photodiodes which needs to filter all but IR.

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