Magneto-optical recording medium and method of making the same and magneto-optical recording medium drive

• Main Author: HOSOKAWA TETSUO,AITA TOMOYUKI,HAGA HIDEKAZU
• Format: Patent
• Language: English
• Published: 23.11.2005
• Edition: 7
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

A magneto-optical disc (11) has a substrate (12). On the surface of the substrate (12), a phase pit (13) is formed. According to the phase pit (13), RAM information is recorded. The phase pit (13) is covered by an undercoat film (14), a recording magnetic film (15), an overcoat film (17), and a reflection film (18). On the phase pit (13), the RAM information is recorded onto a recording magnetic film (15). On the substrate (12), a difference between a first birefringence value of the single path measured with inclination of 20 degrees around the radius passing through the measurement optical beam radiation position with respect to the reference plane orthogonal to the measurement optical beam and a second birefringence value of the single path measured with inclination of 20 degrees around the tangent line of the tracking direction passing through the measurement optical beam radiation position with respect to the reference plane is set to 37 nm or below. Jitter is reduced when reading out the ROM information and the RAM information.