Abstract: A multilayer optical recording medium includes three or more recording layers formed in a thickness direction. Trial writing areas provided in the respective recording layers to adjust the power of recording laser are formed not to overlap at a position in a planar direction in adjacent ones of the recording layers. Further, the trial writing areas are formed to have an overlapping portion at a position in the planar direction in one of the recording layers and at least another one of the recording layers not adjacent to the one of the recording layers.

Abstract: According to the present invention, write pulses are optimized without being affected by the level of skill of an engineer. The present invention relates to the optimization of write pulses for an optical disk recording apparatus for recording an optical signal to, e.g., a DVD-R. A common write pulse which does not depend on various recording conditions is initially set. Pulse set positions affecting on recording quality are sequentially determined in accordance with an adjustment sequence, thus obtaining write pulses suitable for an actual operating environment. In each adjustment step, test recording is performed and a jitter value is measured. Based on a margin curve (quadratic approximation curve) of jitter values obtained by measurements, the optimum setting is obtained. This process is repeated every ordered pulse adjustment position. Finally, recording quality including margin is checked, thus optimizing the write pulses.

Abstract: An optical deflection device having: a rotor unit including a rotary polygon mirror having a plurality of mirror surfaces on the side surface portion and a holding member holding the polygon mirror; an air dynamic pressure bearing including a rotary bearing member to support the rotor unit and a fixed bearing member rotatably supporting the rotary member; and a stator unit which supports the fixed bearing member, including a winding coil oppositely arranged to the magnet, wherein prior to an assembly process, the adhesive agent layer is formed between the outer peripheral surface of the rotary bearing member and the inner peripheral surface of the holding member, the holding member and the rotary bearing member are set at the following condition, (the inner diameter of the holding member before the assembling)?(the outer diameter of the rotary bearing member before the assembling).

Abstract: An optical deflection device having: a rotor unit including a rotary polygon mirror having a plurality of mirror surfaces on the side surface portion and a holding member holding the polygon mirror; an air dynamic pressure bearing including a rotary bearing member to support the rotor unit and a fixed bearing member rotatably supporting the rotary member; and a stator unit which supports the fixed bearing member, including a winding coil oppositely arranged to the magnet, wherein prior to an assembly process, the adhesive agent layer is formed between the outer peripheral surface of the rotary bearing member and the inner peripheral surface of the holding member, the holding member and the rotary bearing member are set at the following condition, (the inner diameter of the holding member before the assembling)≧(the outer diameter of the rotary bearing member before the assembling).