OEM vs Copy LCDs
OEM Screens are screens that come right off an original iPhone. Refurbished screens are OEM screens that have been refurbished at least once, usually using aftermarket glass.
Chinese / Tianma / Copy are terms used to describe screens that do not contain OEM LCD/OLED. These screens are produced in China. They usually have little to no value.
OEM LCDs contain no trade stamps, stickers, or markings on the back of the LCDs. These are the original screens from Apple.
If you look under an OEM Flex Cable, you will see that the ribbons are non-transparent. You will also find an Apple Logo.
If you see any signs of a trade stamp, trade stickers or a missing apple logo, you know the screen is not OEM. Copy LCDs have flex cables that are transparent. They also have flex cables that are completely black.