Spectrometry device

A spectrometry device comprising:

• a) a combining optical system configured to combine rays of light emitted from a measurement point on an object face into one single parallel light beam;
• b) a phase shifter configured to divide the parallel light beam into two in a predetermined first axis direction to form a first light beam and a second light beam, and configured to provide an optical path length difference between the first light beam and the second light beam, the optical path length difference continuously changing along a second axis direction orthogonal to the first axis direction;
• c) an imaging optical system configured to focus, in the first axis direction, the first light beam and the second light beam between which an optical path length difference is given by the phase shifter, on an imaging plane, to form a linear interference image along the second axis direction;
• d) a photodetector having a light-receiving face on the imaging plane and having a plurality of pixels for detecting a light intensity distribution of the linear interference image;
• e) a light-shielding member having a plurality of translucent portions arrayed at predetermined intervals in the second axis direction, the light-shielding member being arranged on the object face or on a surface optically conjugate with the object face with respect to the combining optical system;
• and
• f) a processing unit configured to obtain an interferogram of the measurement point based on an intensity distribution of light in a linear region detected by the photodetector, and configured to acquire a spectrum by Fourier-transforming the interferogram, wherein
• when a focal length of the combining optical system is f1, a focal length of the imaging optical system is f2, an interval of pixels of the photodetector in the second axis direction is P, a difference in optical path length difference given to each of two pixels adjacent to each other in the second axis direction is Δλ, a predetermined wavelength included in a wavelength range of light emitted from the measurement point is λc, and both a length of each of the translucent portions of the light-shielding member in the second axis direction and an interval of two translucent portions adjacent to each other in the second axis direction are L, L is expressed by a following Formula (1)
• L={(λc×f1)/(4×Δλ×f2)}×P (1).

A spectrometry device comprising:

• a) a combining optical system configured to combine rays of light emitted from a plurality of measurement points on an object face into one single parallel light beam;
• b) a photodetector having a plurality of pixels arranged on a light-receiving face;
• c) a phase shifter configured to divide a parallel light beam combined in the combining optical system into two in a predetermined first axis direction to form a first light beam and a second light beam, configured to emit the parallel light beam toward the light-receiving face while providing an optical path length difference between the first light beam and the second light beam, the optical path length difference continuously changing along a second axis direction orthogonal to the first axis direction, and configured to cause the first light beam and the second light beam to planarly enter the light-receiving face so that at least a part of an incident region of the first light beam on the light-receiving face and at least a part of an incident region of the second light beam overlap with each other;
• d) a light-shielding member having a plurality of translucent portions arrayed at predetermined intervals in the second axis direction, the light-shielding member being arranged on the object face or on a surface optically conjugate with the object face with respect to the combining optical system;
• and
• e) a processing unit configured to obtain an interferogram at the measurement point based on an intensity distribution of light along the second axis direction in a region where an incident region of the first light beam and an incident region of the second light beam on the light-receiving face overlap, and configured to acquire a spectrum by Fourier-transforming the interferogram, wherein
• when a focal length of the combining optical system is f, a distance from the combining optical system to the phase shifter is h1, a distance from the phase shifter to the light-receiving face is h2, an interval of the plurality of pixels in the second axis direction is P, a difference in optical path length difference given to each of two pixels adjacent to each other in the second axis direction is Δλ, a predetermined wavelength included in a wavelength range of light emitted from the measurement point is λc, and both a length of each of the translucent portions of the light-shielding member in the second axis direction and an interval of two translucent portions adjacent to each other in the second axis direction are L, L is expressed by a following Formula (2)
• L=[(λc×f)/{2×Δλ×(h1+h2)}]×P (2).