| 摘要 |
<p>PURPOSE:To minimize an average wire length required for a magnetic coil to be wound and to improve the magnetic flux generation efficiency for the electricity consumption, thereby reducing the consumption of electricity by making a cross section of a magnetic core part smaller than an area of a magnetic flux discharging part and also by forming the magnetic coil into a slender shape. CONSTITUTION:A magnetic core part 34 is determined so that its cross section is smaller than an area of a magnetic flux discharging plane 37A at a magnetic flux leading out part 37; besides, a cross section area of the magnetic core part 34 is determined so that while at work, its cross section is small enough to take a value approaching a saturation magnetic flux density Bs. As a result, wire materials of a magnetic coil 32 required for a coil and its resisting value become smaller. When a current is supplied and the magnetic coil 32 is energized, magnetic flux is discharged from the magnetic core part 34 toward a region where the light beam of a photoelectro-magnetic recording film 24 can be irradiated from the magnetic flux discharge plane 37A located at a lower plane of magnetic flux leading out part 37. Then, the photoelectro-magnetic recording film 24 is exposed to magnetic flux that is perpendicular to its plane. Magnetic flux which is passing through its film 24 enters into a yoke 39 through a space and is feedback to the magnetic core part 34 which is magnetically and mechanically coupled to the yoke.</p> |
