Patent ID: 9188543
Filing Date: 2015-11-17
Classification: G01N,G02B

Abstract:
1. An optical system configured to visually inspect a target, the target comprising variable positions with respect to the optical system, the optical system comprising: a polarizer configured to convert an incident light reflected or diffused from the target into linearly polarized light; a light modulating element configured to modulate a polarization state of the linearly polarized light in response to control signals; a lens assembly comprising at least one birefringent element, the birefringent element configured to refract the modulated linearly polarized light with a first polarization state under a first refraction index to enable inspection of the target at a first object position with respect to the optical system, and the at least one birefringent element further configured to refract the modulated linearly polarized light with a second polarization state under a second refraction index to enable inspection of the target at a second object position with respect to the optical system; a detector configured to detect a position of the target with respect to the optical system, the detector further configured to provide positional signals used for automatically switching the optical system between a first inspection mode and a second inspection mode, wherein in the first inspection mode, the target at a first position with respect to the optical system is inspected; and wherein in the second inspection mode, the target at a second position with respect to the optical system is inspected.