| 摘要 |
PURPOSE:To make the titled spectroscope compact by providing an inlet slit on a Rowland circle or the outside, providing a flat image plane within the Rowland circle, and disposing a diffraction grating and the flat image plane in a manner as to satisfy specific relations. CONSTITUTION:Along with a Rowland circle 14, an inlet slit 11, a diffraction grating 12 and a flat image plane 13 are disposed respectively outside, on and inside the circle 14. The incident main rays 15 past through the slit 11 are diffused to a main diffracted rays 16c, and diffracted rays 16a, 16b at both ends of a measuring wavelength region by the diffraction grating 12. The diffraction grating 12 and the flat image plane 13 are disposed in such a manner that the length r0 of the segment where the straight line connecting the centers of the slit 11 and the grating 12 is cut by the circle 14, and the length r' of the segment connecting the center of the grating 12 and the center of the plane 13 satisfy 0.2r0<=r'<=0.8r0. |
