Patent ID: 7378990

Claim:
A laser locus ball apparatus for a keyboard, comprising: a base for containing a space formed therein, wherein the base includes: a top plate with a supporting bore, a first lateral plate depending downward from the top plate and having a locating hole, and two opposite second lateral plates each with an engaging wedge at the bottom wherein the second lateral plates depend downward from the top plate; a laser source generator disposed in the locating hole; a locus ball with an interference strip figure on its surface wherein the ball is moveably received in and supported by the supporting bore such that the lower surface of the ball extends downward from the supporting bore to reflect the light emitted by the laser; a light sensing element disposed in the space formed by the base to capture the light reflected by the ball and to generate a control signal to indicate the movement of the ball; and a key cover with a shape to cover the base completely and having a circular hole at the top to permit the upper surface of the ball to extend outward through the circular hole wherein the cover is secured to the base via the wedges.