Coordinate vector method for optical input device

Claim 1

An optical input device for a cursor or the like based on the coordinate vector method comprising: a moveable light source, a coordinate plane having a grid thereon and a matrix of light sensitive units adapted to be coupled to a central processing unit said grid having a predetermined pitch of equal spacing both in the horizontal direction and perpendicular thereto each line in said grid having a predetermined width, said matrix having light sensitive units of a predetermined dimension horizontally and perpendicular thereto and a predetermined separation distance, the dimension and distance being related to the pitch and line width of the grid; means for directing the light source onto the plane and for projecting a grid image; magnifying means and reflecting means for magnifying the image and directing it onto the matrix, said grid being dimensioned relative to the matrix so that each light sensitive unit will emit either a high or a low signal depending on the intensity of the light striking it the relationship between the dimension and distance between light sensitive units and the pitch and line width of the grid in the image being such that all light sensitive units never emit either a high or a low signal at any position of said light source relative to said grid so that the signals emitted can be interpreted by a central processing to calculate distance and direction as the light source moves across said plane.