| 摘要 |
<p>PURPOSE:To facilitate the adjustment of the optical system with a higher accuracy of displacement and variation in a medium running by recording a speckle pattern generated by a laser light and a pattern during the running thereof in the same optical system supporting the information medium at the state of zero tension. CONSTITUTION:A laser light is generated intermittently from an oscillator 1, expanding the beam diameter with an expander 3, the expanded laser light is branched off in two directions with a splitter 5 and then, irradiates an informations medium 7. A speckle pattern generated by the laser light from the surface of the medium 7 is recorded with a TV camera 8 and the resulting image signal is converted into a digital signal to be memorized into a memory. The memorized information is used to measure displacement and variation of the medium 7 with a computer. Then, optical or magnetic trigger marks recorded on the medium 7 are detected with a detector. In this case, the medium 7 is supported at the state of zero tension with a mechanism 26 or the tension to be applied to the medium 7 can be altered with a mechanism 21.</p> |
