Browse Prior Art Database

Electro Optical Reading System

IP.com Disclosure Number: IPCOM000093500D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Beck, JW: AUTHOR

Abstract

The optical read system detects stored data by passing light beam 1, polarized by the polarizer 2, through memory element 3 which has discrete areas magnetized to indicate recorded data. To read the data, the intensity modulation of the beam caused by the magnetic alignment of the areas of element 3 is detected. The modulated beam is passed through Wollaston prism 4 to obtain the planar polarized beam components. The latter are compared by being detected by photocells 5 and 6 for reading the data. It is advantageous to align the beam and prism such that each photocell receives exactly one half the beam energy. To accomplish this automatically, the photocell signals are fed into a differential amplifier. This generates a signal proportional to the unbalance in the two beam intensities.

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Electro Optical Reading System

The optical read system detects stored data by passing light beam 1, polarized by the polarizer 2, through memory element 3 which has discrete areas magnetized to indicate recorded data. To read the data, the intensity modulation of the beam caused by the magnetic alignment of the areas of element 3 is detected. The modulated beam is passed through Wollaston prism 4 to obtain the planar polarized beam components. The latter are compared by being detected by photocells 5 and 6 for reading the data. It is advantageous to align the beam and prism such that each photocell receives exactly one half the beam energy. To accomplish this automatically, the photocell signals are fed into a differential amplifier. This generates a signal proportional to the unbalance in the two beam intensities. The unbalance signal is applied to a Kerr cell. The latter rotates the polarization of the beam before it enters the prism in a direction to cause the intensity of the two beams from prism 4 to be equal.

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