How To Identify Polarized Sunglasses?

Find an LCD screen, and point the glasses horizontally to the screen. At this time, the lens does not change. Then, when the glasses are turned up and clockwise to a 45° angle, the color of the lens becomes darker, and then rotates back to normal. This is the polarized lens. , if there is no change no matter how you turn it, it is not a polarizer. (Note that it must be an LCD screen)