| 摘要 |
PURPOSE:To produce the optical diffraction grating having high dimensional accuracy of an optical diffraction surface and good parallelism with a housing at the time of formation of the grating to a product by injection molding a long-sized synthetic resin molding which has an H shape in cross section and is formed with many grating grooves in recess parts, then cutting this molding. CONSTITUTION:The many grating grooves having a recessed shape in section are formed on one surface of a planar optical diffraction grating body part consisting of a transparent synthetic resin, for example, polymethyl methacrylate. Supporting parts are formed of the same material as the material of the optical diffraction grating body part on both sides of the optical diffraction grating body part in such a manner that the section shape thereof has an H shape. This production process consists in obtaining the optical diffraction grating 15 by first molding the transmisive synthetic resin molding 13 which has the H shape in sectional shape and is slender by injection molding, then cutting this molding to a prescribed length by a rotary blade tool 14 or laser beam machine, etc. The resulted optical diffraction grating 15 is supported by leaf springs on the inner side of the annular housing and is thereby made into the product. |
