Patent ID: 6081332
Filing Date: 2000-06-27
Classification: G01J

Abstract:
A monochromator comprising:an incident portion upon which light to be measured is made incident;a first optical system for converting the incident light to be measured into parallel rays of light;spectral diffraction means for receiving the light to be measured converted into the parallel rays of light and for outputting the light at an angle which differs depending on wavelength;a second optical system for condensing the output light outputted from said spectral diffraction means at a certain angle;an output portion for outputting the output light thus condensed;angle changing means for making variable at least a relative angle between said spectral diffraction means and said second optical system by one of rotation of said spectral diffraction means;wherein said spectral diffraction means is a reflection-type diffraction grating, and a maximum angle formed by the light reflected from said diffraction grating and condensed by said second optical system and a normal to said diffraction grating is greater than an angle of rotation of said diffraction grating with respect to the reflected light which is condensed; andwherein a center line of an optical path of the light incident from said incident portion is on the same straight line as a center line of said first optical system, and a center line of an optical path of the light reflected from said spectral diffraction means and condensed by said second optical system is on the same straight line as a center line of said second optical system.