ELI5: Explain Like I'm 5

Collimating lens

A collimating lens is like a special kind of magnifying glass that makes light travel in a straight line. You know how when you shine a flashlight, the light goes everywhere and you can't really aim it? Well, a collimating lens makes the light go straight like a laser beam.

It's kind of like if you were trying to shoot a basketball into a hoop. You might throw the ball and it could go anywhere, but if you have someone to help you aim it straight, it's more likely to go in the basket. That's what a collimating lens does with light.

The lens is shaped like a special kind of bowl that makes the light go straight when it hits the lens. So, if you had a flashlight and you put it through a collimating lens, the light would come out the other side in a straight line that you could aim at things.

People use collimating lenses for all sorts of things, like in telescopes or laser pointers, because it helps them focus the light exactly where they want it to go. It's a really cool invention that helps us control light in a new way.