| 摘要 |
PURPOSE:To obtain a 1/2lambda plate and lambda plate by uniaxially stretching a cellulosic film or sheet in such a manner that the measured value of retardation by a polarization microscope attains a specific value. CONSTITUTION:The phase difference plate (1/2lambda plate) is obtd. by uniaxially stretching the cellulosic film or sheet in such a manner that the measured value of retardation by the polarization microscope attains 200-350nm and the phase difference plate (lambda plate) is obtd. by uniaxially stretching the cellulosic film or sheet in such a manner that the measured value of retardation by the polarization microscope attains 475-625nm. Cellulose diacetate, acetic acid/lactic acid cellulose resin, etc., are used as the material to constitute the cellulosic film or sheet. The phase difference plate which generates 1/2lambda retardation or lambdaretardation is thereby obtd.
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