There are three types of computer mice; the mechanical mouse, which uses a small rubber ball, the optical mouse, which uses optical light and the laser mouse, which uses a laser light to calculate position and movement. The optical mouse was introduced into the market in 1999 and was developed by Agilent Technologies. It came as a welcome replacement to the mechanical mouse, which gets dirty easily and processes information slowly. The optical mouse has a tiny camera, which determines position and speed by taking thousands of pictures each second. The mouse is able to work on any surface without using a mouse pad, making it even more convenient.
The optical mouse works by using an LED (light emitting diode), which is a very small diode that emits light. The LED is red in color and it bounces light off the desk surface or mouse pad onto a Complimentary Metal-Oxide Semiconductor (CMOS) sensor. With the recent development of laser-based optical mice, it is possible for the mice to detect even more surfaces than the LED technology. It therefore enables the user to use the laser-based optical mouse on many more surfaces than they would use with an LED mouse.
Once light is reflected onto the CMOS sensor, it sends each reflected image to the digital signal processor (DSP) for analysis. The DSP is then able to detect image patterns and analyze the movements of the patterns in relation to the previous image. It uses these patterns to determine if there has been mouse movement and if so, the distance and speed of the movement. It then sends the coordinates to the computer. The computer responds by moving the cursor according to the coordinates it receives from the mouse. Because of the high speed of these movements, the computer receives mouse coordinates hundreds of times per second which ensures that the cursor movement is smooth.
An optical mouse uses LED as opposed to a mechanical mouse which uses a rubber ball. This means that dirt cannot get inside an optical mouse and interfere with its tracking sensors. It also does not have any moving parts which means chances of wear and failure are reduced. The tracking resolution is increased due to the use of LED and CMOS which means they are much more reliable and smooth than mechanical mice. Optical mice are also highly popular because they can be used on any surface and do not require a special surface like the mechanical mice.