| 摘要 |
PURPOSE:To obtain a phase detection signal having preferable S/N ratio by providing lap wound FG coil on an FG coil substrate, thereby raising a phase detection voltage level. CONSTITUTION:An FG coil substrate 26 is secured to the lower substrate 12 opposed to a permanent magnet 22, a servo circuit is integrally print-wired on the substrate 26, and an FG coil 28 is similarly printed oppositely to the magnet 22. The coil 28 is formed of double lap winding of the outer FG coil winding and the inner FG coil winding, thereby sufficiently raising the phase detection voltage level to obtain a phase detection signal having preferable S/N ratio. |
