| 摘要 |
PURPOSE:To attain rugged recording on a tape shaped recording medium wound around the circumference of a rotary drum while performing focusing control, by incorporating a recording optical system including a semiconductor laser at the inside of rotary drum. CONSTITUTION:The tape shaped recording medium 1 is wound around the rotary drum 2 for running. A laser beam 11 for recording reflected on a mirror 12 is converted into an elliptic beam at a cylindrical lens 20 as required and performs recording on the recording medium 1 through a convex lens 21, a half mirror 22, mittors 23, 24 and dichroic mirrors 43, 44. The optical system comprising semiconductor lasers 33, 34, beam splitters 39, 40, 1/4 wavelength plates 41, 42, photodetectors 45, 46 is for the focusing of the recording laser beam. |
