LAMINATED PHASE DIFFERENCE PLATE WHICH ROTATES POLARIZATION AXIS AND PROJECTION TYPE LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a laminated phase difference plate which rotates the polarization axis with a high rotation efficiency of the polarization axis in a wide wavelength range of a visible ray region by laminating plural phase difference plates having specified ranges of retardation in such a manner that I'/slow phase axes are neither parallel nor perpendicular to each other. ;SOLUTION: This plate is produced by laminating at least two phase difference plates having 160 to 300nm retardation in such a manner that the slow phase axes make an angle neither parallel nor perpendicular to each other. The wavelength dependence (wavelength dispersion α) of the retardation of the phase difference plate used is preferably 1.08 because the variance in the rotation efficiency of polarization axis decreases. The wavelength dispersion αis obtd. by formula α= R(486)/R(589), and for example, a is 1.06 for a polycarbonate phase difference plate which is preferably used and 1.11 for a polyether sulfone phase difference plate. In formula. R(486) and R(589) mean the retardation at 486nm and 589nm wavelengths respectively.;COPYRIGHT: (C)1998,JPO