| 摘要 |
PURPOSE:To obtain a tracking system facilitating assembly and adjustment and dissolving the problem in a three beams method and simultaneously to transfer information at high speed by magnetic field modulation overwrite and to make a device a large capacity by super high resolution. CONSTITUTION:In an optical path from a laser light source to an optical information recording medium 3, an element 1 superposing and constituting a diffraction grating 1A inclined by a prescribed angle to the prolonging direction of the track 3A of above-mentioned recording medium 3 and the diffration grating 1B inclined to the opposite direction to the inclination direction of the diffraction grating 1A and inclined by a prescribed angle on the same surface is arranged. |
