| 摘要 |
PURPOSE: To improve mass production by using a simple device without requiring strict environmental management and to form rugged patterns on a spherical surface by forming the patterns with a light shielding material on the spherical surface side of a glass substrate at least one surface of which is spherical. CONSTITUTION: The glass substrate 12 is placed on a stage 14 and a spherical photomask 11 with concentrical diffraction grating patterns is brought into close contact with the spherical surface coated with a photoresist 13 of the glass substrate 12. The photoresist is exposed to UV rays 16 from the photomask 11 side by an exposure device 15. The photoresist 13 is then exposed in compliance with the patterns of the photomask 11. The exposed photoresist 13 is developed to obtain the rugged patterns 17 of the concentrical diffraction gratings; thereafter, the rugged patterns 17 are cured by post baking at a prescribed temp. The rugged patterns having the concentrical diffraction gratings are formed on the concave spherical surface in this stage by the simple method having mass productivity. |
