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I need to know how LED status lights like these on my Bose Q35 headphones, are made? Is it a light guide? some kind of foil or what?

enter image description here

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  • \$\begingroup\$ I don't know about those particular ones, but most are PCB light pipes (do an internet search on those three words and you'll get lots of hits). Basically transparent plastic that goes from the LED to the outside of the product. \$\endgroup\$
    – Puffafish
    Apr 12 '19 at 10:00
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    \$\begingroup\$ Maybe you can find clues by watching repair / teardown videos for this or comparative headphones. \$\endgroup\$
    – Huisman
    Apr 12 '19 at 10:06
  • \$\begingroup\$ Actually I have tried watching tear downs. And I have also looked at lots of light pipes. But in this particular case it seems like the pipe and headphone plastic are molded together - not just inserted. You can't feel any level different or even a small gap. \$\endgroup\$
    – Jolle
    Apr 12 '19 at 10:20
  • \$\begingroup\$ What makes you think that the LEDs aren't mounted right behind the coloured filters on the case? \$\endgroup\$
    – Transistor
    Apr 12 '19 at 10:20
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    \$\begingroup\$ A clear filter. The part may be solid clear plastic overprinted in grey, except for the windows and then overprinted in white with the white legends. The alternative is a tricky moulding process. \$\endgroup\$
    – Transistor
    Apr 12 '19 at 10:29
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(images from this eBay listing)

The LEDs are ordinary SMT LEDs mounted on the PCB.

enter image description here

The light pipes are a custom single molding of transparent plastic that is glued and perhaps heat sealed into place (or maybe those are just locating posts).

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enter image description here

It's not difficult with modern techniques to match those small dimensions in the small molded pieces so that they appear to be perfectly flush, even with curved surfaces etc.

It goes without saying that all molded parts are custom designed and molded for this particular product, they are not off-the-shelf parts.

You can buy standard light pipes from various suppliers such as Lumex and Bivar, check a distributor catalog.

More on light pipes and light pipe design here:

Light Pipe Design Guide - Fundamentals of LED Light Pipes - VCC

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They are known as LED Guides They are specially designed structure with mold such that led light attached on PCB will be directly guided to upper surface with approximately full intensity.

LED guide is the small pipe like structure not more than 4-5mm long and 2-3 mm in dia which got directly cover the led on PCB when PCB is placed in enclosure. You can ask any manufacturer for this type of guide.

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