Abstract: There is disclosed a focus condition detecting device for a camera.The focus condition detecting device has a preliminary correlation calculation means for calculating correlations between first and second image signals with a relatively low accuracy and a principal correlation calculation means for calculating correlations between first and second image signals with a relatively high accuracy on the basis of data obtained in the preliminary correlation calculation.

Abstract: A focus condition detecting device which generated first and second light intensity distribution signals representing light intensity distributions on first and second arrays arranged to receive lights having passed through different areas of the exit pupil of an objective lens is arranged so as to divide the first light intensity distribution signal into a plurality of blocks. Each of the portions of the first light intensity distribution signal belonging to the respective blocks is shifted relative to the second light intensity distribution signal by sequentially changing an amount of shift, so that correlations therebetween are calculated for finding the amount of shift providing the highest correlation.

Abstract: In a focus condition detecting arrangement for use in a photographic camera, a focus condition detecting device including photo-sensor arrays having sensitivity with respect to a visible light and an infrared light from a target object to be photographed produces a focus condition detection signal based on an output of the photo-sensor arrays. A contrast detecting device which detects the visible light and the infrared light from the target object for detecting contrasts of the target object with respect to the respective lights, and a correcting means corrects the focus condition detection signal based on the output of the contrast detecting device, so that a corrected focus condition detection signal of the target object with respect to the visible light region is obtained.

Abstract: In a focus detection of a camera a pair of imaging lens elements are formed of a transparent plastic material as a part of a plastic plate. A supporting structure for support of the lens elements is provided with a pair of bosses projecting from a base body to loosely fit in a pair of boss receiving holes formed on the plastic plate. An adhesive is applied to the top ends of the bosses and one of the plate surfaces of the plastic plate which does not face the base body. As the plastic plate is fixed to the base body only by the adhesive, freedom for the plastic plate to expand and contract due to temperature changes is improved and residual deformation of the plastic plate which affects the distance between the lens elements is minimized.

Abstract: In a focus condition detecting device of the type in which a pair of re-imaging lenses together with a condenser lens form a pair of re-images of an object image on a line sensor such that the distance between the corresponding points of the re-images on the line-sensor varies with the focus condition of a camera objective lens forming the objective image, the line sensor is located in front of a plane conjugate with a predetermined focal plane of the camera objective lens with respect to the condenser lens and the re-imaging lenses, so that the distance between the corresponding points of the first and second re-images on the line-sensor can be detected with resolution higher than one pitch length of the photocells of the line sensor.

Abstract: A focus condition detecting device of the type in which a pair of re-imaging lenses together with a condenser lens form a pair of re-images of an object image on a linesensor, such that the distance between the corresponding points of the re-images on the linesensor varies with the focus condition of a camera objective lens has an improved construction for positioning the linesensor with respect to the device with high accuracy. A field aperture mask having a field aperture is arranged optically behind a plane conjugate with the linesensor with respect to the re-imaging lenses and the condenser lens such that a pair of defocused images of the field aperture are formed on the linesensor by the re-imaging lenses and the condenser lens with respective one side blurred borders of the defocused images overlapping one another to make a V-shaped peak or dip of illuminance on a photocell of the linesensor located on the optical axis of the device, when the field aperture mask is uniformly illuminated.

Abstract: In a focus condition detecting device wherein an object image formed by an objective lens of a camera is re-imaged as first and second images on first and second photocell arrays through a pair of re-imaging lenses, a pair of plano-convex lenses are used as the re-imaging lenses to improve the accuracy of focus condition detection. The device is formed into a module and the plano-convex lenses are formed on a transparent plate supported on a main body of the module. An extremely thin masking member for blocking a part of light rays incident on the plano-convex lenses to form the first and second images is sandwiched between the transparent plate and a surface of the module main body. This arrangement prevents the masking member from rising and/or warping which otherwise causes inconsistency in luminous levels between the first and second images on the first and second photocell arrays. Various examples of the arrangement of the masking member to prevent its rising and/or warping are proposed.

Abstract: A focus detecting photoelectric device includes a plurality of photodiodes each formed by an amorphous silicon layer sandwiched between transparent and non-transparent electrodes. The photodiodes are provided in pairs and are aligned in an array and deposited on a glass plate such that the transparent electrode is directly mounted on the glass plate. The photodiodes in a pair are located closely adjacent to, but in a spaced relation with, each other and are electrically connected in series to each other. An image formed on the photodiodes in a pair effects the generation of photocurrent from the photodiodes such that the photocurrents from both photodiodes are approximately the same when the image is out of focus, and they vary from each other as the image becomes sharp.

Abstract: The disclosure relates to a focus detecting device for detecting a focusing condition of an objective lens on a focal plane by the detection of contrast of an image formed by the objective lens. The device includes an elongated biconcave cylindrical lens for forming a line image, a glass plate positioned parallelly to the cylindrical lens, and a plurality of photodiodes deposited on the opposite flat surfaces of the glass plate in arrays parallel to the axial direction of the elongated cylindrical lens such that the photodiode arrays on the opposite flat surfaces are disposed alternately in an interlaid manner. When the line image formed on the photodiodes deposited on one surface of the glass plate is front-focus condition and the line image formed on the photodiodes deposited on the other surface of the glass plate is rear-focus condition, a detector indicates that the line image formed on a plane between the opposite flat surfaces is in-focus condition.