Diffraction grating
    17.
    发明专利

    公开(公告)号:GB977340A

    公开(公告)日:1964-12-09

    申请号:GB3964161

    申请日:1961-11-06

    Abstract: 977, 340. Diffraction gratings. COLEMAN INSTRUMENTS CORPORATION. Nov. 6,1961, No. 39641/61. Heading G2J. The spread of the blaze of an expellets grating is increased by providing each working surface with more than one blaze angle. Each working surface may be divided into two distinct planes as at 1-2, 2-3 &c. in Fig. 2 by moving a conventional diamond cutting tool from right to left of the grating so that deformations are formed at the ridge between the grooves during each pass. In an alternative form, the two planes are as at 8-6 and 6'-7 in Fig. 3. A grating of this form is produced by first cutting the usual grooves 4-8-4 , 4'-8'-4" &c. and then changing the tool angle and aligning the tool with the peaks 4, 4 , 4 before making a second cut during which the upper part of the fan 8-4 , 8 -4 &c. is turned over. The grating may have carved working surfaces, these being produced by rotating a grooved grating relative to a metal source and evaporating the metal (e.g. aluminium) so as to build up metal over the top of each groove. Alternatively the original grooves may be partially filled in with gelatin or an epoxy or polyester resin 9, Fig. 5, which may be cast on in liquid form and allowed to harden.

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