公开(公告)号：US3609723A

公开(公告)日：1971-09-28

申请号：US3609723D

申请日：1969-12-24

Applicant: IBM

Inventor： ALSTAD JOHN K ,  WIITALA JAMES R

IPC: G02B26/06 ,  G02F1/09 ,  G02F1/315 ,  G11B11/10 ,  G11B11/105 ,  G02F1/22

CPC classification number: G11B11/10 ,  G02B26/06 ,  G02F1/09 ,  G02F1/315 ,  G11B11/10547

Abstract: Magnetic information is converted to optical signals by placing a coupled piezoreflective-magnetostrictive film layer between the information-containing medium and a light source; and the pattern of magnetization on the medium induces a similar pattern of elongation or contraction in the magnetostrictive film which imparts a strain at corresponding locations in the piezoreflective film and a resulting change in reflectivity of the film. Accordingly, the reflectance of light incident upon the piezoreflective film surface can be sensed to determine the presence or absence of magnetization at particular locations on the information-containing medium.