| 摘要 |
PURPOSE:To increase brightness and contrast ratio and to reduce a cost by specifying the stretching axial angle of a phase plate, the absorption axial angles of an upper polarizing plate and lower polarizing plate as well as the retardation values of a liquid crystal display cell and the phase plate. CONSTITUTION:One sheet of the phase plate 2 is provided in the black and white display type liquid crystal display element having the STN type liquid crystal display cell 1 of 200 to 300 deg. twist angle, the upper polarizing plate 3 and the lower polarizing plate 4. The stretching axial angle of this phase plate 2 is set at 30 to 60 deg., the absorption axial angle of the upper polarizing plate 3 at 0 to 15 deg., and the absorption axial angle of the lower polarizing plate 4 at 160 to 170 deg.. Further, the retardation value of the liquid crystal display cell 1 is set at 700 to 950nm, the retardation value of the phase plate 2 at 500 to 650nm and the difference in the retardation values between the liquid crystal display cell 1 and the phase plate 2 at <=300nm. Coloration is averted in this way even if one sheet of the phase plate is used and, therefore, the brightness and contrast ratio are high. The brightness at the time of, on is 70cd and the adequate black and white display is obtd. |
