mouse Button

Optical mice rely entirely on one or more light-emitting diodes (LEDs) and an imaging array of photodiodes to detect movement relative to the underlying surface, eschewing the internal moving parts a mechanical mouse uses in addition to its optics. A laser mouse is an optical mouse that uses coherent (laser) light

The earliest optical mice detected movement on pre-printed mousepad surfaces, whereas the modern LED optical mouse works on most opaque diffuse surfaces; it is usually unable to detect movement on specular surfaces like polished stone. Laser diodes are also used for better resolution and precision, improving performance on opaque specular surfaces. Battery powered, wireless optical mice flash the LED intermittently to save power, and only glow steadily when movement is detected.