Abstract: A focus detecting device for determining a focused state of a photo taking optical system through a video signal obtained from an image sensor comprises a detecting circuit arranged to detect focused degrees obtained by scanning at a plurality of scanning line parts of an image sensing plane; a correlation determining circuit arranged to determine a correlation between positions on scanning lines at which the focused degrees are detected during the processes of the scanning lines; and a computing circuit arranged to determine a focused state by computing the focused degrees detected from the scanning line parts which are determined to be correlated to each other by the correlation determining circuit.

Abstract: A structure of attaching to a metal shaft a ceramics bearing which comprises an inner ring, an outer ring and rolling members and in which at least the inner ring is made of ceramics. The inner ring is made of silicon nitride or sialon molded by the hot press sintering process or the hot isostatic press sintering process. The shaft is press-fitted in the inner ring with an interference of not greater than a specified value.

Abstract: A distance measuring apparatus which emits light toward an object, receiving light reflected by the object, and measuring the distance of the object. This apparatus includes receiving means for receiving the reflected light, and the receiving means has at least two receiving areas. According to a disclosed technique, a mean value of photoelectric outputs from the respective receiving areas is calculated, and the distance of the object is measured on the basis of the difference between the mean value and the photoelectric output from either of the receiving areas. According to another disclosed technique, stabilization is provided with respect to amplifier means for amplifying the photoelectric outputs from the receiving means and integrating means.

Abstract: An improved paperboard feeding machine has a tiltable lift, a lifting yoke provided on the lift and arranged for operation by respective electric motors for the lift and the yoke. Each of the motors is responsive to change in the effective number of the poles in each of the motors.