METHOD AND DEVICE FOR MEASURING CELL GAP OF LIQUID CRYSTAL DISPLAY LIQUID CRYSTAL DISPLAY AND RETARDATION PLATE USED FOR MEASURING CELL GAP OF LIQUID CRYSTAL DISPLAY

摘要

It is possible to measure the cell thickness easily and accurately without applying voltage to the liquid crystal cell. The liquid crystal molecules exist because the glass plates, color filters, transparent electrodes, and alignment layers, which are the constituent members of the liquid crystal cell, are optically isotropic. A retardation (d _LC · Δn) of only a liquid crystal layer, a liquid crystal display device capable of obtaining cell thickness, a cell thickness measuring device, and a measuring method are provided. A cell thickness measuring device for measuring the thickness of a liquid crystal cell of a liquid crystal display device having a liquid crystal layer in which a liquid crystal molecule in the liquid crystal region is oriented vertically when no voltage is applied and a pair of substrates sandwiching the liquid crystal layer. It has the stage 1 and polarizer 23 which mount the liquid crystal cell 5 which installed the pair of uniaxial retardation plate which has retardation in the slow-axis direction on both outer surfaces, and also has a phase difference. A light source 2 emitting polarized light in an azimuth direction 44 ° to 46 ° with respect to the slow axis direction of the plate, and an analyzer 1 provided with polarizer and cross nicol with respect to the polarized light, and detecting the amount of transmitted light of the polarized light A photodetector 3 and a rotating device 4 for changing the polarization incident angle of the polarized light from a direction approximately perpendicular to the slow axis direction of the retardation plate.