Generating Bias Field for Magneto-Optic Recording Using Permanent Magnets and Mechanical Actuator
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
We have found a method which uses actuator-driven permanent magnets to generate a bias field. The method has the advantage of requiring very little power. Another advantage is that magnetic fields as high as 2 kilogauss can easily be obtained. Practical mechanical actuators allow switching times between 1 and 10 milliseconds, comparable to switching times of electromagnets. Fig. 1 shows the basic idea. Two rare earth magnets are joined in a junction with opposing polarities. An actuator translates the magnets in a direction perpendicular to the tracking direction of the head. The purpose of the actuator is to position one of the magnets over the focused laser beam during erasing, and to position the other (Image Omitted) magnet over the beam during writing. This is shown in Fig. 2.