| 摘要 |
PURPOSE:To suppress the generation of interference fringes in the stage of manufacturing a diffraction grating and to manufacture the beautiful pattern of a diffraction grating by diffusing the light of the component in the direction perpendicular to the direction where the interference fringes array as diffused light and averaging the phases of the light. CONSTITUTION:Light 22 from a laser light source is divided to two beams of light by a half mirror 24. The light past the mirror 24 is reflected by a mirror 26 and is then expanded by lens 28. The expanded light passes through a one-way diffusion plate 30 and arrives as the light diffused in an arrow 38 direction at a photosensitive material 12 by passing through a mask 10. On the other hand, the light reflected from the mirror 24 is reflected by a mirror 32 and is expanded by the lens. The expanded light passes through a one-way diffusion plate 36 and arrives as the light diffused in the arrow 38 direction at the material 12 by passing through the mask 10. Both beams of the light form the interference fringe on the material 12. Such fringe is recorded and the diffraction grating having the pattern which can be made by the mask 10 is formed. The unnecessary interference fringe is formed in the direction perpendicular to the arrow 38 direction in this stage, but the light has the diffusivity in the arrow 38 direction and therefore the phases of the interference light superpose randomly on each other at one point on the material 12 and the unnecessary interference fringe is annihilated.
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