Abstract: A photoelectric transducer element responsive to ambient light and a combination of ambient and projected light from light emitting apparatus operates with a predetermined cycle by signals from an oscillator. This produces respective output signals which are then stored on first and second storing apparatus. Signals from the storing apparatus provide information necessary for photographing, since the storing operation is synchronized with the oscillating operation.

Abstract: In the disclosed distance measuring device a light source projects light on an object to be photographed. A photo-electric converter for receiving light reflected from the object includes at least one photo-electric converting portion whose electric charge varies according to the quantity of light incident thereon. A control includes a first electric charge store which stores an electric charge produced at the photo-electric converting portion while the light is projected from the light source, a second electric charge store which stores an electric charge produced at the photo-electric converting portion while light is not projected from the light source, and a detector which detects at least one of the amounts of electric charge stored at the first and second electric charge stores. The control varies the quantity of light projected by the light source on the basis of the result detected by the detector.

Abstract: In a focus detecting apparatus wherein an imaging optical system is disposed rearwardly of the predetermined imaging plane of an objective lens to thereby form a plurality of object images on the basis of lights passed through different portions of the pupil of the objective lens and each of the object images is detected by a line sensor comprising a plurality of photoelectric conversion elements to thereby detect the focus condition of the objective lens from the amount of deviation of each object image, a field limitation plate having a plurality of openings and an optical filter for causing the characteristics of the light passed through the openings of the field limitation plate to differ from one another are provided near the predetermined imaging plane of the objective lens. Thus, the apparatus is adaptable for different focus detection conditions and is very simple in construction.

Abstract: In a focus detecting apparatus for detecting the focus state of an objective lens on the basis of a light passing through the objective lens, a field lens is disposed near the predetermined imaging plane of the objective lens, and a projecting optical system for projecting the light from a light source onto an object through a first area of the pupil of the objective lens and a light-receiving optical system for forming a plurality of images on a sensor on the basis of lights passing through second and third areas of the pupil of the objective lens are disposed rearward of the image of the pupil of the objective lens formed by the field lens, whereby both focus detection based on the projected light and focus detection not based on the projected light can be accomplished.

Abstract: In the disclosed photo-electric conversion device, a light source repetitiously emits light and a photo-electric converter receives reflected light originally generated by the source and ambient light. A first store stores the output of the photo-electric converter when the light source emits light and a second store stores data from the photo-electric converter when the source does not emit light. A gate transfers the output from the converter to the first and second stores. A pulse generator controls the gate for transferring the converter output to the first store and the second store during every light emitting cycle of the light source.

Abstract: A distance detection apparatus detects distances to a far object and a near object in a view field, weights the detected distance information, and selects the distance information on the near object to finally detect the distance.

Abstract: A plural number of transparent plates are arranged in parallel, a relief type diffraction grating is formed on the surface of one of the transparent plates and both transparent plates are joined so to make a beam splitter which is used as the light measuring device of a camera.

Abstract: Disclosed is an area type beam splitter disposed in the light beam from an imaging optical system to split the light beam. This beam splitter has dot-like reflecting surfaces formed on a substrate. The dot-like reflecting surfaces are arranged at pseudo-random.

Abstract: A focusing device for focusing a photographic camera or the like on the image of an object to be photographed is arranged to control and adjust the operating time of each performance of a focus detecting process according to a signal produced from reflection light receiving means during a series of processes. These processes include projecting a light on the object, receiving a reflection light from the object, computing an extent of deviation of a photo-taking lens from an in-focus position on the basis of a signal produced from a light receiving device; and driving the lens to shift its position.

Abstract: The disclosed distance measuring device is arranged to project light on an object. Reflected light from the object is received by a photo-electric converter to shift the position of a photo-taking lens to an in-focus position on the basis of a signal produced from the photo-electric converter. The projected light and/or the reflected light is divided into a multiplicity of light fluxes for the purpose of broadening and simplifying the distance measuring range and accuracy.

Abstract: A focusing detecting system for discriminating a focusing state of an object lens by detecting a relative positional relation of a plurality of object images formed by light fluxes from the object lens, by photo-sensing means is disclosed. A plurality of object images are formed based on a light flux from a center area of the object lens around an optical axis and a plurality of object images are formed based on a light flux an area in the periphery of the center area around the optical axis, by optical means disposed behind an image plane of the object lens. Light shielding means having a plurality of slits is disposed near the image plane. By those means, a state is which the object images based on the light fluxes from the center area of the object lens around the optical axis and the peripheral area are detectable and a state is which the object images based on only the light flux from the center area of the object lens around the optical axis is detectable are discriminated.

Abstract: In an in-focus state detection device for determining a defocus quantity of an object lens based on a relative positional relationship of a plurality of object images, a contrast of at least one of the object images is detected before the relative positional relationship of the object images is detected, and the relative positional relationship of the object images is detected only when the contrast is larger than a predetermined level so that a determination precision and a response speed of the device are improved.

Abstract: In a focus detecting device, an object's image formed on a prescribed image plane of a photo-taking lens is once again formed by a secondary imaging optical system disposed behind the prescribed image plane into two non-superposed object's images based on light flux portions symmetrically split relative to the optical axis of the photo-taking lens; light sensitive elements are respectively disposed in positions where these images of the object are re-imaged by the secondary imaging optical system; and an in-focus state of the photo-taking lens is arranged to be detected by detecting the relative positional relation of these reformed images of the object by means of these light sensitive elements. The focus detecting device includes light splitting means which is arranged in the secondary imaging optical system to split a light flux coming from the exit pupil of the photo-taking lens into a middle part portion and a peripheral portion.

Abstract: This invention relates to an apparatus for controlling a D.C. power transmission system having a line-commutated converter which is connected between a first A.C. system and D.C. power transmission lines and which performs power conversion between A.C. power and D.C. power, and a forced-commutated converter which is connected between the D.C. power transmission lines and having a second A.C. system and which performs power conversion between A.C. power and D.C. power. In order to control transmission power in the two-terminal D.C. power transmission system wherein the two A.C. systems are associated by direct current, a control apparatus for a D.C. power transmission system according to this invention includes a voltage detector which detects a D.C. voltage of the D.C.

Abstract: A thyristor apparatus employing light-triggered thyristors comprises forward voltage detecting circuits (15) and a thyristor number detecting circuit (17). The forward voltage detecting circuits (15) detect forward voltages applied to light-triggered thyristors (13) to provide detected signals. The thyristor number detecting circuit (17) is responsive to the detected signals to cause light-triggered thyristors in a thyristor arm (U) to be turned on simultaneously in the case where the number of the light-triggered thyristors being supplied with forward voltages is one or more but not more than a predetermined number. Accordingly, if and when an overvoltage is applied to the thyristor arm (U), overvoltage suppressing elements (14) are prevented from being damaged even if partial commutation failure occurs in the light-triggered thyristors.

Abstract: In the disclosed camera, an optical arrangement projects substantially collimated light rays from a light emitter toward an object through an objective system in a finder, and a light receiver produces a signal that determines the relationship between the object and the camera by detecting the light from the objective system after reflection by the object.

Abstract: A power converter adapted for use in a high-voltage circuit and equipped with a plurality of arms each comprising a plurality of thyristor elements connected in series, wherein an overvoltage limiter having an overvoltage limiting element and means for short-circuiting the ends of the overvoltage limiting element in response to flow of a load current therein are connected between the anode and the cathode of each thyristor element. The short-circuiting means has a gap between the two electrodes connected respectively to the anode and the cathode of each thyristor element, and also a metal layer of a low melting point which is molten by heat generated due to the flow of a load current in the overvoltage limiting element to fill the gap.

Abstract: Disclosed is a device for splitting incident light on an image forming optical system by means of a relief type diffraction lattice and for detecting a portion of the light. The device is constructed with a transparent substrate, on one surface of which there is formed the relief type diffraction lattice which satisfies the condition of N.lambda..perspectiveto.2n.DELTA. (where N is an integer; .lambda. is a wavelength contained in the incident light; n denotes a refractive index of the transparent substrate; and .DELTA. represents a quantity between peak and valley on the surface of the relief type diffraction lattice), a reflective film coated on the lattice surface, a transparent filling layer having the substantially same refractive index as that of the transparent substrate, which perfectly fills the peak and valley (or surface irregularity) of the relief type diffraction lattice, and light detectors.

Abstract: A phase type diffraction grating and a microprism for splitting the light beam from an objective lens into three light beams. The three light beams are split in one direction by the diffraction grating and are directed onto three rows of line sensors disposed on the same plane. In the two optical paths between the diffraction grating and the line sensors, there is disposed an optical path length difference imparting element for forming on the line sensors images at a predetermined focal plane of the objective lens and planes forward and rearward of the predetermined focal plane. Thus, the line sensors detect the images at the predetermined focal plane and at planes forward and rearward of the predetermined focal plane.

Abstract: A light measuring device for measuring the light in the field by means of a light sensing means sensing the light reflected of the shutter plane provided in the neighborhood of the image forming plane of the photographing lens or the film plane or both of them. In the optical path of the reflected light a change over means for changing over the light sensitivity distribution of the metering so as to enable the change over of the light.