Patent ID: 6631001
Filing Date: 2003-10-07
Classification: G01J

Abstract:
A spectral image input device comprising:an image forming optical system for forming an image of image light on an image forming surface; a phase difference generating unit disposed anterior to the image forming surface in a direction of image light travel; and an area optical element disposed at an optically equivalent position with the image forming surface of the image forming optical system, wherein the phase difference generating unit comprises sequentially in the direction of image light travel: a polarizer, a first optical element, an analyzer, and a second optical element, the polarizer for transmitting only polarized light in a specific direction; the first optical element formed of a solid material having a birefringence, the first optical element arranged such that a principal refraction index axis is inclined 45Â° relative to a polarization angle of the analyzer, the first optical element generating a phase difference in accordance with a wavelength of the image light based on a difference in a thickness of the first optical element in the direction of image light travel, the first optical element having an optical function surface inclined at a predetermined angle relative to the direction of image light travel; the analyzer for transmitting only the image light of a polarization angle of 90Â° relative to the direction of the polarized light of the polarizer; and the second optical element formed of solid material having birefringence on a principal refraction index axis inclined 90Â° relative to the principal refraction index axis of the first optical element through the optical function surface.