Method for measuring gap of liquid crystal cell

摘要

The polarization angle theta 1 of a polarizer ( 14 ) is set, and the reflection intensity S 1 in a cross Nicol state and the reference reflection intensity Ref 1 of a liquid crystal cell ( 15 ) are measured. A different polarization angle theta 2 is then set, and the reflection intensity S 2 in a cross Nicol state and the reference reflection intensity Ref 2 of the liquid crystal cell are measured. The rations S 1 /Ref 1, S 2 /Ref 2 of measured intensities and the ratio S 1 .Ref 2 /S 2 .Ref 1 is determined in order to cancel the background components of the reference reflection intensities Ref 1, Ref 2 thus determining the value of cell gap accurately.