| 摘要 |
PURPOSE:To reduce the number of rotating mechanisms to one and to stably form a diffraction grating by providing a rotating base which supports one mirror and a photosensitive face so that they form a prescribed angle. CONSTITUTION:When a photoresist as a photosensitive material is preliminarily applied on the surface of an object 26, this photoresist is subjected to interference exposure with luminous fluxes 25 and 30, and as the result, the photoresist is developed and the surface is etched with the developed photoresist as the mask to form a diffraction grating on the object 26. A half mirror 21 and a mirror 27 are fixed to a straight-ahead base 31, and the object 26 and a mirror 29 are fixed to a rotating base 32, and they are so installed that the optical path of luminous fluxes 23, 28, and 36 and that of luminous fluxes 22 and 25 have the same length. When the rotating base 32 is rotated, the straight-ahead base 31 is moved in the direction perpendicular to the reflection face of the mirror 27 so that images of luminous fluxes 25 and 30 are overlapped on the surface of the object 26. Thus, luminous fluxes 23, 28, and 30 re moved in parallel and adjusted the optical path length to stably form the diffraction grating. |
