Optical modulating element and electronic apparatus using it

A display apparatus which makes an indication by irradiating the light of one light source containing the wavelengths of a plurality of colors on a transmission or reflection type display means, said apparatus including an optical modulating element, said apparatus displays images corresponding to the time period for an afterimage effect, the optical modulating element switching the color of the light that passes within a time period for display of the image for each color;

• the optical modulating element comprising:
• a pair of neutral polarizers, said neutral polarizers being the only polarizers in said optical modulating element;
• a plurality of adjacent crystal panels, in each of which a nematic liquid crystal having birefringence and a twisting angle of 0.degree. is sealed, arranged from an inlet side to an outlet side of said modulating element, all of said panels being positioned between the pair of neutral polarizers;
• and
• means for changing the retardation And of each liquid crystal panel,
• wherein the axis of polarization of the neutral polarizer on the outlet side is parallel to the direction of polarization of the straight polarizing component or to the direction of the major axis of the elliptical polarizing component of the output light of the last liquid crystal panel toward the outlet side, and when transmitting light of a wavelength .lambda..sub.o through the liquid crystal panels, the retardation And of each liquid crystal panel is adjusted to satisfy the following equation:
• .increment.nd/.lambda..sub.o =(2m-1)/2
• where .increment.n is the anisotropy of refractive index of the nematic liquid crystal, d is the thickness of a liquid crystal layer contained in the liquid crystal panel, and m is an integer,
• wherein the optical axis direction at an exit side of a first liquid crystal panel toward the inlet side of said optical modulating element is at an angle of 2.alpha. with the plane of polarization of the neutral polarizer at the inlet side of said optical modulating element, the optical axis direction of a second and successive liquid crystal panels is in the direction intersecting diagonally with the orientation of a liquid crystal panel preceding the liquid crystal panel, at an angle of 2.alpha., and the plane of polarization of the neutral polarizer at the outlet side of said optical modulating element is parallel to the optical axis direction at an exit side of a last liquid crystal panel towards the outlet side of said modulating element.