Kanzaki Paper Manufacturing Co., Ltd.

New Oji Paper Co, Ltd.

Kyoji Imagawa

Kiyokazu Sakai

Shinichi Nagata

Osamu Tomita

A compensation polarizing plate which is superior in polarization characteristic to a polarizing filter layer of a composite layer sample is arranged on the polarization filter layer side of the composite layer sample whose polarizing filter layer has an insufficient degree of polarization, and polarization transmission axes of the polarizing filter layer and the compensation polarizing plate are kept in parallel with each other to compensate the polarization characteristics of the polarization filter layer. Measurement for obtaining the retardation value and the optical principal axis direction of the sample is carried out in the state of the compensated sample.

Method of and apparatus for measuring retardation of composite layer

A phase plate is superposed on a sample, and this phase plate is so adjusted that the phase difference of the total retardation of the sample and the phase plate is integral times 2.pi. with respect to a measuring beam of a first wavelength, so that retardation can be correctly measured even if an order is increased. In this state, a measuring beam of a second wavelength which is approximate to the first wavelength is employed and two polarizing plates maintaining polarizing directions in parallel nicol relation are singularly rotated with respect to the sample which is arranged therebetween. The ratio Im/Io between maximum value Io and minimum value Im of currently transmitted light intensity is applied to a previously prepared relation between the order n of retardation and this ratio Im/Io to derive the order of retardation of the sample, to thereafter obtain correct retardation.

Growing community of inventors

Hyogo, Japan

Kyoji Imagawa