MEASURING METHOD OF THICKNESS OF GAP OF LIQUID CRYSTAL CELL

Japanese Patent JPH04307312

A

PURPOSE:To precisely measure the thickness of a gap of a liquid crystal cell. CONSTITUTION:A liquid crystal cell 5 having the twisting angle theta is inserted between arm analyzer 6 and a polarizer 4. The polarizing angle of the analyzer 6 is inclined 45 deg. from the direction of orientation of the incident face of the liquid crystal cell, and the polarizing angle of the polarizer 4 is inclined further 45 deg. from the direction of orientation of the projecting face of tone liquid crystal cell. In this state, the intensity of the light passing through the polarizer 4 is measured. The phase difference of the double refraction d n is operated based on the measured intensity of light, and consequently the thickness (d) of the gap of the liquid crystal cell is measured from the phase difference d n and the known difference n of the index of double refraction of the liquid crystal cell. Since it is possible to measure the phase difference of the double refraction of the liquid crystal by a considerably simple formula with the twist of the liquid crystal taken into consideration, the thickness of the gap of the liquid crystal having any twisting angle can be measured. Moreover, the distribution and uniformity of the thickness of the liquid crystal cell can be controlled, and therefore an inferiorly uniform liquid crystal cell can be removed, and a liquid crystal of good quality without color irregularity can be selected.

INOUE TOMOKUNI

JP7115091A

October 29, 1992

April 03, 1991

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OTSUKA DENSHI KK

G01B11/06; G01N21/23; G02F1/13; G02F1/137; G02F1/139; (IPC1-7): G01B11/06; G02F1/13; G02F1/137

Hirokatsu Kamei (1 person outside)

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