ZOOMING MECHANISM TO BE USED FOR EYE TRACKING SYSTEM, SYSTEM AND METHOD FOR SENSING EYE MOVEMENT, AND METHOD FOR ADJUSTING INTERVALS BETWEEN A PLURALITY OF OPTICAL SPOTS SENT TOWARD EYE IN EYE MOVEMENT SENSOR

摘要

PPROBLEM TO BE SOLVED: To provide a zooming mechanism for an eye tracking system. PSOLUTION: The zooming mechanism 30 includes a pyramidal prism 31 having a plurality of reflecting small faces 32 or transmissive small surfaces crossing at an apex. Incident light beams 35 sent toward the respective small surfaces 32 of the prism 31 are reflected or refracted on a plane nearly vertical to an optical axis 34 to form a plurality of optical spots disposed around the optical axis 34. The prism 31 can make translation along the optical axis 34 among a plurality of axial direction positions for changing intervals between the optical spots substantially without varying its size. The optical spots are desirably sent toward a boundary regulated by the two adjacent surfaces of an eye having different reflectances. Reflected energy is detected from each of a plurality of positions to adjust the size of a pattern formed by the optical spots substantially without varying the diameters of the individual spots. PCOPYRIGHT: (C)2004,JPO