| 摘要 |
PURPOSE:To obtain a small-sized optical recording and reproducing head which can irradiate closely positioned two spot lights upon a disk, by combining optical beams different in wavelength from two light sources in one direction and fetching reflecting lights from the disk separately in two directions. CONSTITUTION:The 1st optical beam 10a is stopped to, for example, an almost circular shape as shown by ''L'' upon a track 16 provided on a disk 5 by means of the 1st lambda/4 plate 13 and stopping lens 14 after passing through the 1st and 2nd polarization beam splitters. The 2nd optical beam 17a radiated from the 2nd light source 17 is expanded in one direction only by a cylindrical lens 18 and, after passing through the 2nd polarization beam splitter 12 and 2nd lambda/4 plate 19, reflected by a separate filter 20 to the amount of nearly 100%. The reflected optical beam 17a again passes through the lambda/4 plate 19 and its polarizing direction is turned by 90 deg. in the direction shown by the arrow B. The polarized optical beam 17a is this time reflected by the 2nd polarization beam splitter 12 to the amount of nearly 100% and form a light spot which is elongated in, for example, the track direction as shown by the ''M'' on the track 16 of the disk 5 after passing through the 1st lambda/4 plate 13 and stopping lens 14. |
