MAGNETO-OPTICAL DETECTING DEVICE AND DETECTING METHOD

• Main Authors: ABE KATSUO, FURUSAWA KENJI, FUJIMAKI SHIGEHIKO, KATAOKA HIROYUKI
• Format: Patent
• Language: English
• Published: 26.12.1990
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

PURPOSE:To accurately detect a magnetic characteristic within a minute extent all over the magnetic disk in a non-broken state and in a non-contact state by utilizing a magnetic force-effect that the rotation of the polarizing surface of the light reflected on the surface of a magnetic medium differs according to the direction of the magnetization. CONSTITUTION:The reflected light beam of a light beam which is made incident on the magnetic disk 5 is minutely polarized with being influenced by the magnetic force-effect. The reflected light beam is condensed by a condenser lens 6 and divided in two equal parts by a half mirror 7, and then detected by photodetectors 10 and 11 through analyzers 8 and 9. Transmitted light beams mutually become reverse code signals with maximum contrast by the photodetectors 10 and 11. Two kinds of signals are detected as a difference signal 12 by a differential amplifier 13 so as to function as a differential signal in a differentiator 14. The signal obtained in a photodetecting part is transferred to a control part. The sampling and the digital conversion of the signal are performed by a digital storage oscilloscope 16 and furthermore, the signal is transferred to a host computer 17. And then, the waveform of the incorporated signal is graphically displayed and also a magnetic parameter such as a coercive force and a aspect ratio, etc., is displayed with computing by the computer 17.