| 摘要 |
<p>PURPOSE:To accurately detect the displacement of a heat mode recording material from a reference position and to prevent it from improperly writing by finishing the detection of the displacement by displacement detecting means until writing on the center of a recording material by an optical beam is finished. CONSTITUTION:An optical beam radiated from a semiconductor laser 54 is irradiated by a first mirror 58 to a heat mode recording material 10. The beam is reflected by the recording layer 12 of the recording material 10, and focused by a photodetecting lens 60. A displacement detecting optical beam radiated from the lens 60 is reflected by second and third mirrors 62, 64 substantially perpendicularly to an optical axis A, and radiated to the photodetecting face of a PSD 66. The detection of the displacement detecting beam by the PSD 66 is so controlled by a controller 67 as to be conducted during a period from the time of write starting to the intermediate ground point of writing. Thus, the displacement of the flat material 10 before writing can be effectively detected, and it can prevent the displacement from being erroneously detected by the uneven part of the material 10 after writing.</p> |
