1. Stack two polarized lenses vertically. If it is opaque, it means a true polarizer. Because the polarizer lens is specially designed to allow only parallel light to pass through the lens, most of the light is when the two lenses are stacked vertically. Will be blocked. When you buy, as long as such a simple operation, you can immediately know the authenticity and good or bad of the product.
2. Using the discriminating plate that discriminates the polarizer, the naked eye does not look like a shark image, but with a polarizer, you can see the shark. On the contrary, if it is not a polarizer, you can't see the shark.
3. Use the mobile phone to identify the true and false polarizer to select a picture on the phone, put the ordinary sunglasses in front of the phone screen, and see the phone screen through the sunglasses without any change. The polarized glasses are placed in front of the mobile phone, and the screen of the mobile phone can be seen through the lens to become flickering, and the light and shadow changes are obvious.