| 摘要 |
790,928. Spectrometers. PARSONS & CO.. Ltd., C. A. June 7, 1956 [June 21, 1955], No. 17936/55. Class 97(1) The plane ruled diffraction grating P of a spectrometer is rotated about an axis A by engagement of the circular contour of a body C with a straight line B attached to the grating at its pivoted axis, the body C being moved along a straight guide F by a screw M so that the centre of curvation O of its circular surface passes through the axis A. By choosing suitable dimensions an exact linear relationship may be established between the turns of the screw and the reciprocal of the wavelength emerging from the grating in a given direction. In a modification the axis of the screw may be perpendicular to the line OA, the screw engaging a sloping sur- - face on the body C: Alternatively the screw M may engage a pivoted lever which moves the body C. |
