Abstract: An optical apparatus comprises an optical device having an optically functional material sandwiched between a pair of substrates with electrodes formed on opposing surfaces. The optically functional material has such a characteristic that intensity of light issuing from the optical device changes asymmetrically in response to inversion of the polarity of an applied external field. Pulse voltages of one polarity for determining the intensity of the issuing light and pulse voltages of an opposite polarity are applied from a source at a predetermined period so that an average voltage is zeroed within the predetermied period. The issuing light intensity under the application of the pulse voltages of one polarity and the issuing light intensity under the application of the other pulse voltages are selected or changed by a switching unit.

Abstract: A driving method for an optical printer and an optical printer having a liquid-crystal light switching element including a ferroelectric liquid crystal sandwiched between a pair of plates provided with electrodes on adjacent surfaces thereof. The liquid-crystal light switching element is disposed between a light source and a movable photosensitive surface and controlled so as to at least one of transmit and block light from the light source to the photosensitive surface for enabling a printing operation. Voltages v.sub.1 and v.sub.2 are applied to the liquid-crystal switching element substantially in accordance with the equation ##EQU1## and the intensity of light from the light source incident on the liquid-crystal switching element is controlled so that incident light intensity during a period T.sub.2 is weaker than the incident light intensity during a period T.sub.1, where t.sub.0, t.sub.1, t.sub.2 and t.sub.3 represents times, T.sub.1 (=t.sub.1 -t.sub.

Abstract: In a display panel consisting essentially of a pair of substrates whose opposed surfaces are equipped with transparent conductive layers and at least one of which consists of an organic polymer film, and of a display member interposed between said pair of substrates, the improvement wherein said organic polymer film is a uniaxially stretched polyester film.

Abstract: A liquid crystal display device is disclosed in which a liquid crystal material mixed with a dichroic dye is held between a pair of substrates whose facing surfaces are provided with electrodes, so that a picture element is made up of a pair of facing portions of the electrodes and a portion of the liquid crystal material sandwiched by the facing portions, in which a reflecting plate is adjacent to one of the substrates, and in which at least one of the substrates is formed of a birefringent material having slow and fast principal axes of birefringence. In the above device, an angle between the direction of the absorption axis of the dichroic dye and one of the principal axes of birefringence of the substrate is selected so that the contrast and viewing-direction characteristic of the device can be improved.

Abstract: This invention relates to a liquid crystal display element comprising a pair of transparent substrates, electrodes formed on the individual surfaces thereof facing each other, a liquid crystal material layer held between the substrates, and gap controlling material for keeping the gap between the substrates, and is characterized in that the gap controlling material is dispersed and fixed on the substrate surface by an insulating coating film such as an orientation controlling film.When the gap controlling material is thus dispersed and fixed, it does not move between the substrates, and hence the change of the gap length between the substrates is prevented, so that there can be obtained a liquid crystal display element in which the distance between the substrates is uniform.