PROCESS OF MANUFACTURE OF PAIR OF METROLOGICAL HOLOGRAPHIC DIFFRACTION GRATINGS Russian patent published in 1996 - IPC

FIELD: optical instrumentation engineering. SUBSTANCE: invention refers to manufacture of holographic diffraction gratings designed for use in metrology. In compliance with process measurement and indicator gratings are manufactured. For this one of side faces of backing 1 of measurement grating is machined with optical precision and light sensitive layer 2 is deposited on it. Then system of periodic lines 3 grouped in sections arranged in succession along direction perpendicular to lines is formed. Boundaries of two adjacent phased sections overlap each other phases of superimposed lines coincide. Later second system of lines 4 grouped into separate sections 5-8 shifted in phase relative to each other is formed on part of light sensitive layer 2 free from lines 3 within limits of width of zone of these lines. In this case density of lines in these sections and their inclination relative to lines 3 of measurement grating are determined from proper mathematical expressions depending on density of lines 3. Then null marks are formed in light sensitive layer 2 on one side of systems of lines 3 and 4 on straight line perpendicular to lines 3 but not crossing them. One null mark 9 corresponds to systems of lines 4 and one or several null marks 10 spaced periodically - to system of lines 3. Indication grating id manufactured by copying matrix including system of lines 4 and null mark 9 corresponding to it with basing along side surface of backing 1 machined optically. For circulation of measurement gratings copies are made from starting measurement grating 3 and with null marks 10 corresponding to it in the same way. Precision of manufacture of copies of pairs of gratings grows sufficiently thanks to formation of systems of lines 3, 4 and null marks 9, 10 during one cycle in interferometer with the use of basing along side surface of backing 1 machined optically. EFFECT: increased precision of manufacture of copies of gratings. 2 cl, 8 dwg