Can an optical mouse that uses optical sensors be placed on nearly all types of flat surfaces?

Yes, but the reflective surface may cause odd behaviors.

You don't need to, but you can in order to prevent scratches

Most devices in this industry use lenses. Some products, however, do not utilize lenses

An optical mouse is a computer mouse which uses an optical sensor as opposed to mechanical means to detect user input. Optical mouses are generally more reliable, have greater sensitivity, and can...

There are quite some differences between an optical mouse and a laser mouse. One of the most noticeable differences is the type of rays coming out of the mouse. Now,we all know that from an optical...