Q. What are LED pens used for?

Answer

LED pens, as their name implies, are pens that double as flashlights, making them ideal for businesspeople on the go. With just the press of a button, a user pen will illuminate its writing surface, allowing a user to see what the writing is even in the dark. A lens focuses the LED's light directly where it's needed, so a user won't blind anyone else in the room. The term "light pen" refers to a stylus-like light-sensitive computer input device used for selecting the text, drawing images, and interacting with user interface elements on a display device. The light pen was formerly a popular input device, but it was phased out because its operating principle is incompatible with today's LCD panels.