| 摘要 |
PURPOSE:To improve the performance of an optical deflector by engraving and providing a groove for generating a dynamic pressure, on the outside periphery of a fixed shaft of a static pressure fluid bearing, utilizing a static pressure when starting a rotation of the optical deflector, and switching it to a dynamic pressure driving, after it has reached a prescribed revolving speed. CONSTITUTION:On the upper face of a lower frame 4, a spiral groove 52 is engraved and provided so as to surround a revolving shaft 8, and on a part of this groove, a discharge port of a thrust fluid passage 18. Accordingly, a fluid which is discharged from the thrust fluid passage 18 through a radial fluid passage 15 from a hollow thrust hole 10 floats and rotates a thrust receiving member 30. When operating an optical deflector, first of all, it is started by utilizing a static pressure fluid bearing, and when the optical deflector has reached a prescribed rotating speed, it is operated as a dynamic pressure fluid bearing by operating a fluid on a herringbone groove which has been provided on the outside periphery of the revolving shaft. In this way, this optical deflector can be driven freely at a low speed and a high speed, and its performance is improved. |
