公开(公告)号：JPH1166227A

公开(公告)日：1999-03-09

申请号：JP15259998

申请日：1998-06-02

Applicant: PHASE METRICS INC

Inventor： PHILIP GREGORY ROBERTS

IPC: G06K9/20 ,  G11B5/127

Abstract: PROBLEM TO BE SOLVED: To eliminate the need for precise control over the position of a substrate by providing light sources which are arranged in an arcuate array. SOLUTION: An optical character recognition(OCR) system has one illuminator array 110 and a camera 120. The camera 120 is placed at an angle θ with respect to the normal of a target 130. The camera 120 has a lens 122, having a visual field for reading a mark etched on the surface of the target 130. An image of the mark is formed on a lens 122 as a result of light being reflected by the surface of the target 130. The illuminator array 110 is placed at a proper position on the x-y plane of a three-dimensional positioning system. The illuminator array 110 is arranged in arcuate array and provides illumination light for the target 130 on the surface of a slider. The illuminator array 110 consists of plural light sources 112a to 112n for emitting light beams 114a to 114n respectively, and the respective light sources are arranged at a distance S from adjacent light sources.