Patent ID: 9581842
Date: 2017-02-28
CPC Classifications: G01N,G02F

Claim:
1. A liquid crystal modulator for detecting a defect of a substrate, the liquid crystal modulator comprising: a reflection layer configured to reflect light; an electrode provided on the reflection layer; a liquid crystal layer provided between the reflection layer and the electrode and including hybrid aligned nematic liquid crystal molecules whose pre-tilt angle gradually increases from a first alignment layer adjacent to the reflection layer to a second alignment layer adjacent to the electrode, wherein the hybrid aligned nematic liquid crystal molecules near the first alignment layer are substantially horizontal and the hybrid aligned nematic liquid crystal molecules near the second alignment layer are substantially vertical; and a polarizer provided on the electrode, wherein when the hybrid aligned nematic liquid crystal molecules are arranged along an electric field established by an applied voltage, the hybrid aligned nematic liquid crystal molecules near the first alignment layer remain substantially horizontal.