Patent ID: 7492468
Filing Date: 2009-02-17
Classification: G01B

Abstract:
1. A surface measuring apparatus for measuring a position on a surface of an element to be mounted thereon, comprising: a measurement frame comprising a mount for mounting an element to be measured; a stage comprising a rotatable device, said stage being movable in at least a first direction relative to said measurement frame; and a contactless distance measurement device for measuring in said first direction a distance between said measurement frame and a predetermined measurement surface provided on said rotatable device, said rotatable device further comprising: a second distance measurement device, for measuring in a second direction a second distance between said device and a selected position on a surface of an element mounted relative to said measurement frame; and a rotation measurement device for measuring an angle of rotation between said first and second direction, wherein at least said first distance measurement device comprises an interferometer and said measurement surface is formed by a reflective member that has a polyhedral or circular shape over at least said measurement surface, and said reflective member is comprised in a housing provided on said stage, and wherein said reflective member is coupled directly to said second distance measurement device, said housing comprising a focusing member for focusing light from said first distance measurement device on said reflective member, so that a reflective light beam emanates virtually from the central axis of said reflective member.