Correctional technique on angle error in the manufacture of symmetric triangular groove shape metal grating

摘要

As a special type of grating, symmetric triangular groove shape metal grating is applied to the moire fringe testing system, whose symmetric shape can increase brightness and contrast. In the manufacture of this grating, due to the structure and work character of the machine for ruled grating, the errors come from apex angle and two base angles are technical difficulties. Reverse certification method is presented. If the grating is irradiated by He-Ne Laser beam in auto-collimation, according to the ratio of energy of positive-negative diffraction order pair, we can evaluate the errors in apex angle and two base angles on symmetric triangular groove shape grating. This kind of symmetric triangular groove shape metal grating is fabricated, whose uniformity in experimental value and theoretical value of the apex angle and blaze angle grating is completed. The energy of positive-negative diffraction order pair is almost equal and the error is less than 1%. Practices have proved that the corrections of apex angle and blaze angle can make the balance of positive-negative diffraction order energy.