| 摘要 |
PURPOSE:To enable the measurement of beam waste at a high accuracy in a short time, by providing a plurality of slits vertical to the optical axis of a laser beam emitted from the optical head. CONSTITUTION:A transparent disk 50 is arranged so that it transverses the optical axis of a laser beam 12 emitted from an objective lens 11 of an optical head 10. The disk 50 turns with a slight surface deviation and a number of non-transparent reflection films are provided thereon radially from the center thereof at an equal space to form a slit 51. A laser beam 12 passes through the slit 51 to be received with a sensor 60 while a part thereof is reflected and returned to the optical head 10 to a focus sensor 101. Then a differentiator 70 is connected to the sensor 60 while a differential amplifier 80 done to a focus sensor 101 and both outputs thereof can be observed with an oscilloscope 90. Thus, the beam waste can be measured at a high accuracy in a short time. |
