公开(公告)号：SE343705B

公开(公告)日：1972-03-13

申请号：SE1384767

申请日：1967-10-10

Applicant: IBM

Inventor： DUDA W ,  FLEISCHER H ,  REYNOLDS J

IPC: G05D3/20 ,  G11C13/04 ,  B23Q15/00 ,  G11C13/02

Abstract: 1,138,128. Read-only stores. INTERNATIONAL BUSINESS MACHINES CORP. 4 Sept., 1967 [12 Jan., 1967], No. 40317/67. Heading G4A. Positioning means is controlled by position detecting means responsive to the frequency pattern produced by a Lippmann film registration area in or on the object to be positioned. As described, the object is a Lippmann film optical read-only storage plate, i.e. a transparent photographic plate in which information is stored as light reflecting layers with characteristic spacing by directing light of selected frequencies at areas of the plate e.g. by use of lasers, grating, and electro-optic deflector, to set up standing waves, then removing the plate, developing it, and replacing it. Data is read using selected frequency light again, a grating to separate the frequencies reflected, and photodetectors. To facilitate accurate positioning on replacement, registration information in three areas was recorded along with the data. Registration information is read from two of the areas alternately and compared. The table on which the plate is mounted is rotated in a sense determined by the difference until identical signals are obtained from both areas, then the table is moved rectilinearly in X and Y directions until the signals from the two areas reach standard (equal) values.