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I took apart a giant projection TV and there were a bunch of these lining the screen mount.
(lemmy.world)
I feel like they probably have something to do with light level detection or infrared signal receiving but I genuinely have no idea. They could just as likely be part of the sound system for all I know.
The TV is a Sony KP-43T85T or similar. The service manual is here with on page 55 the exact part: https://www.manualslib.com/manual/772761/Sony-Kp-43t85t.html?page=55#manual
It states "3D COMB FILTER" and is part of the picture in picture mode. It's probably an optional upgrade, which is why it's on a separate board if I were to guess.
Looking up 3D comb filters, I found this:
https://www.edn.com/revisiting-the-analogue-video-decoder-brushing-up-on-your-comb-filters/
My guess is this is a CRT TV, and these sensors precisely measure the timing of the scan line in the overscan regions (off the sides of the display), and allow the TV to make adjustments.
Wow. Thank you so much. Now I need to find out if I can use it in some weird home brew project!
Awesome!
I found manuals of a similar product, but it did not have the correct labels, may have been a different brand or older models.
I give you props on finding the part!