Abstract: A raindrop sensor detects an amount of raindrops landed on a window glass and outputs a measurement signal to a microcomputer. The microcomputer calculates an average amount of raindrops by averaging a predetermined number of the latest measurements. The microcomputer calculates an interval time for the wiper based on the calculated average amount of raindrops. At this time, when the calculated average amount of raindrops deviates from a predetermined reference value, the microcomputer calculates the average amount of raindrops using a smaller number of the latest measurements.

Abstract: A torque sensor has a torsion bar coaxially in alignment with input and output shafts, a ring shaped magnet fixed to an axial end of the input shaft, a pair of magnetic yokes fixed to an axial end of the output shaft, and a magnetic sensor for detecting magnetic flux density generated between the pair of magnetic yokes. Each of the magnetic yokes is provided with claws, which are circumferentially spaced at constant intervals, and whose number is equal to that of each of N and S poles alternately arranged circumferentially in the magnet. Each center of the claws coincides with a boundary between immediately adjacent N and S poles of the magnet, when the torsion bar is not twisted. The magnetic sensor is inserted into an axial gap between the pair of magnetic yokes without contacting the magnetic yokes.

Abstract: A precipitation sensor has a prism bonded to a front windshield, a beam transmitter, and a beam receiver. The prism has an entry-side prism wall, a connection wall, and an exit-side prism wall. The entry-side prism wall of the prism parallelizes light transmitted from the beam transmitter by refracting them on a convex lens face. The parallelized light is reflected from a parabolic outer face of the prism wall toward the inner face of the windshield. The parallel beams reflected from the inner face of the front windshield are reflected from a parabolic outer face of the exit-side prism wall and then focused on the beam receiver through a convex lens face of the prism wall. The convex shapes of the lens faces form arcs, the centers of which are aligned with the beam transmitter and the beam receiver, respectively.

Abstract: Burning and flickering effects of a display screen in a matrix-type liquid crystal display device using an anti-ferroelectric liquid crystal medium are avoided by controlling the duration of the holding period to a certain length. A control circuit measures the cycle of the input of the picture signals to one picture frame, and the duration of the blanking period is controlled according to the result of the measurement in order to keep the duration of the holding period constant.

Abstract: A matrix liquid crystal display using an antiferroelectric liquid crystal prevents the displayed image from tailing off. The liquid crystal display includes a liquid crystal panel, a temperature sensor, a control unit, a scanning electrode driver circuit, and a signal electrode driver circuit. When the temperature of the liquid crystal panel is detected by the temperature sensor, the control unit increases or reduces the de-select period according to the detected temperature. The scanning electrode driver circuit and the signal electrode driver circuit serve to drive scanning electrodes and signal electrodes, respectively included in the liquid crystal panel according to control signals from the control unit and from a level converter. These control signals include a signal indicating the controlled de-select period. Thus, the controlled de-selected period is secured.

Abstract: There is disclosed herein a ferroelectric liquid crystal electro-optical apparatus of the maxtrix type comprising a liquid crystal cell having first and second electrode substrates which include n striped line electrodes and m striped column electrodes, respectively, facing at right angles each other. A ferroelectric liquid crystal is put in therebetween so as to form n by m indication picture elements. Also included in the apparatus a scanning drive device adapted to supply a scanning signal and a data signal to the n striped line electrodes and the m striped column electrodes, respectively. The ferroelectric liquid crystal shows three stable states in accordance with an application voltage and has a light transmittance with a hysteresis sufficient to a dynamic drive in accordance with increase or decrease in the application voltage in a predetermined voltage range.

Abstract: Making method for a phosphor layer of a small diameter cathode ray tube comprises application of a centrifugal force of above 100G in a direction parallel to the axis of a glass bulb toward its bottom panel to become a face plate, thereby forcedly making sedimentation of phosphor powder onto the inner surface of the bottom panel, and thus, by adoptation of the centrifugal force, a phosphor layer of very fine and dense configuration and uniform thickness is obtainable even using such small medium grain size of phosphor powder of under 4 .mu.m.