A screen privacy filter is a thin, transparent sheet that attaches to a computer or mobile device screen. Its primary purpose is to limit the viewing angle of the screen, making it difficult for people nearby to see the content displayed. This is especially useful in public places, such as cafes or airports, where sensitive information may be visible to others. These filters work by using a technology similar to that of sunglasses, allowing only the person directly in front of the screen to see the content clearly. They are commonly used in offices and by individuals who want to protect their privacy while working on devices like laptops or tablets.