How do LCDs work to make a light - Polarizer Basic 

pull out from ur tv / pc moniter

I'm working in the display company can get these easily.

Does the company sell those materials to the public, if they do, how can I get them?

No. Our company uses them by buying, but I don't know information of vendors because I'm an engineer using just them in the other field.

It depends on a kind of displays. LED would be used to a backlight module of LCD TV which is according to almost LCD LED TV. If you mean LED is for LCD then It is necessary to get POL. But If you mean LED is LED board or OLED TV then your opinion is correct