An apparatus for optical navigation. The apparatus has a surface
comprising an aperture, wherein the surface is configured to be moveable
against an illuminated surface having a detectable texture. An optical
motion detection circuit is integral to the apparatus and optically
coupled to the detectable texture of the display screen. The optical
motion detection circuit produces motion signals indicative of motion of
the surface relative to the detectable texture of the illuminated
surface, wherein the optical motion detection circuit is operable to
detect the detectable texture without requiring an integral illumination
source.