Abstract: A rotation angle sensor including a magnet rotatable about an axis, a first and second yokes arranged around said magnet and diametrically opposed to each other, and a Hall effect device disposed between the first and second yokes. The yokes include arcuately curved pole piece portions radially opposed to the magnet and overhang portions extending angularly inwardly from the pole piece portions across the axis of the magnet, respectively. The overhang portions have a generally sector shape and cooperate to define a gap therebetween within which the Hall effect device is disposed. Leakage flux reducing members circumferentially extends between the pole piece portions.

Abstract: A rotation angle sensor including a magnet rotatable about an axis, a first and second yokes arranged around said magnet and diametrically opposed to each other, and a Hall effect device disposed between the first and second yokes. The yokes include arcuately curved pole piece portions radially opposed to the magnet and overhang portions extending angularly inwardly from the pole piece portions across the axis of the magnet, respectively. The overhang portions have a generally sector shape and cooperate to define a gap therebetween within which the Hall effect device is disposed. Leakage flux reducing members circumferentially extends between the pole piece portions.

Abstract: A rotation angle sensor including a magnet rotatable about an axis, a first and second yokes arranged around said magnet and diametrically opposed to each other, and a Hall effect device disposed between the first and second yokes. The yokes include arcuately curved pole piece portions radially opposed to the magnet and overhang portions extending angularly inwardly from the pole piece portions across the axis of the magnet, respectively. The overhang portions have a generally sector shape and cooperate to define a gap therebetween within which the Hall effect device is disposed. Leakage flux reducing members circumferentially extend between the pole piece portions.

Abstract: A rotation angle sensor is provided, including a casing, and a magnet positioned in the casing. The magnet has a first magnetic pole end and a second magnetic pole end. First and second yokes are positioned at a first predetermined space relative to the first magnetic pole end of the magnet, and a third yoke is positioned at a predetermined space relative to the second magnetic pole end of the magnet. The third yoke is further positioned between the magnet and an extending portion of the first yoke, and is also positioned between the magnet and an extending portion of the second yoke. A first signal output element, which is positioned between the third yoke and the extended portion of the first yoke, outputs a first signal corresponding to an area ratio between the magnet and the first yoke. A second signal output element, which is positioned between the third yoke and the extended portion of the second yoke, outputs a second signal corresponding to an area ratio between the magnet and the second yoke.

Abstract: A rotation detecting apparatus comprises a casing body including a head portion, an installation bracket portion and a connector portion. A recess portion is formed at a side surface of the head portion. A magnet, a Hall-effect device and a circuit base plate are installed in the recess portion and are then covered with a sealing member. Further, a clearance groove is formed in the vicinity of a wall defining the recess portion. Therefore, the number of parts and the production cost of the apparatus are reduced, and the waterproof performance thereof is improved.

Abstract: A sensor used to detect an opening angle of, for example, a throttle valve comprising: a pivotable valve axle arranged so as to be pivoted through a pivoted angle; a magnet; a first magnetic circuit, through which a first magnetic flux branched from a total magnetic flux developed from the magnet is passed; a second magnetic circuit, through which a second magnetic flux branched from the total magnetic flux developed from the magnet is passed; a pair of first and second Hall effect devices, the first Hall effect device being interposed in the first magnetic circuit so as to output a first signal according to the first magnetic flux passing therethrough and the second Hall effect device being interposed in the second magnetic circuit so as to output a second signal according to the second magnetic flux passing therethrough; and a calculation circuit, in response to the first and second signals of the first and second Hall effect devices, for calculating a level of a detection signal (So1, So2) of the sensor fr

Abstract: A rotation angle sensor for sensing a rotation angle of a pivotal member, such a throttle valve shaft, comprises a first unit including a magnet member and a second unit including first, second and third magnetic piece members which are circumferentially arranged to concentrically surrounds the magnet member. The first and second magnetic piece members are symmetrically arranged with respect to the magnet member. A structure is employed for connecting one of the first and second units to the pivotal member. A first electric device is employed for generating a first signal in accordance with a density of magnetic flux produced between the first and third magnetic piece members, and a second electric device is employed for generating a second signal in accordance with a density of magnetic flux produced between the second and third magnetic piece members.

Abstract: A focussing apparatus and a focus correcting apparatus both derive information representing a distance from an AF sensor. A CPU stores lens travels at the telephoto end position, and distance information is utilized to retrieve one of the lens travels. A zoom coefficient is found in accordance with a zoom encoder value, and the CPU performs an arithmetic operation to derive a lens travel for a particular focal length which is currently being used. The zoom encoder value is also used to read deviation data D.sub.k, which relates to a variation from camera to camera, from E.sup.2 -PROM, and such data is used to correct the lens travel to determine a final lens travel.

Abstract: A zoom mechanism comprises a zoom system lens holding frame composed of at least one frame for changing its focal length by moving it in a direction of the optical axis, a focus system lens holding frame which moves together with the zoom system lens holding frame during a zooming operation and is held in the latter so as to be movable in a direction of the optical axis during a focusing operation, a detector for detecting movement of the zoom system lens holding frame from a predetermined reference position, a memory unit for storing a difference in position of the focus system lens holding frame from its normal position in relation to movement of the zoom system lens holding frame from the reference position as an amount of correction and for delivering a stored value corresponding to movement of the zoom system lens holding frame from the reference position a which movement is detected by the detector, and a controller for moving the focus system lens holding frame in relation to the zoom system lens holdi

Abstract: A range detector detects a range to an object to be measured by projecting light rays from a light source onto the object and producing an output signal by receiving light rays reflected by the object by a single semiconductor position detecting element (PSD) disposed at a given base length apart from the light source. The position detecting element is provided with signal electrodes of N pieces (N.ltoreq.3) in a separate manner and in a direction of the base length so that a light receiving plane of the PSD is divided into (N-1) areas. The range detector is capable of reducing a detectable close range so as to cover a very wide range by selectively deciding an output from these signal electrodes in accordance with a range to be measured without degrading accuracy of range measurements.

Abstract: An exposure control device for camera includes a detector for detecting the opening of a sector shutter. By detecting an actual opening of the sector shutter, an amount of incremental exposure is calculated based on the opening and the corresponding time interval. Such amount is accumulated to provide an accumulated value. An amount of proper exposure is determined on the basis of photographing information including the brightness of an object being photographed and a film speed. The sector shutter is controlled in accordance with the accumulated value and the amount of proper exposure.