Abstract: This invention intends to provide a catadioptric reduction projection optical system of a construction in which an on-axis light beam is used in a catadioptric system and resolving power is prevented from being deteriorated, and more particularly a catadioptric reduction projection optical system having a first lens unit G1 of negative refractive power for diffusing a light beam from a reticle 1, a semi-transparent mirror 5 for transmitting therethrough the light beam from the first lens unit G1, plane parallel plates 2, 3 and 4 disposed obliquely with respect to the optical axis between the first lens unit G1 and the semi-transparent mirror 5 for correcting aberrations attributable to the semi-transparent mirror 5, a concave reflecting mirror 7 for returning the light beam emerging from the semi-transparent mirror 5 to the semi-transparent mirror 5 while converging the light beam, and a second lens unit G3 of positive refractive power for converging the light beam returned to the semi-transparent mirror 5 an

Abstract: In a cata-dioptric optical system having a combination of a reflection system and a refraction system for reduction-projecting an object on a first plane onto a second plane, a polarization beam splitter and a quarter wavelength plate are provided to split the incident light and the reflected light. The light beam directed to the polarization beam splitter is converted to a substantially collimated light beam by a first group of lenses. A second group of lenses are arranged between the polarization beam splitter and a concave reflection mirror to diverge the light beam. The light reflected by the concave reflection mirror is directed back to the polarization beam splitter with a substantially collimated state by the second group of lenses. The light beam from the second group of lenses transmitted through the polarization beam splitter is focused by a third group of lenses having a positive refraction power to form a reduced image.

Abstract: A laser beam harmonics generator comprises a laser beam source for emitting a laser beam, a harmonics generator for generating harmonics of the laser beam in response to the irradiation of the laser beam, and a displacement unit for relatively displacing the harmonics generator and the laser beam substantially perpendicular to a light path of the laser beam.

Abstract: An interferometer for measuring the spherical accuracy of a surface to be measured in accordance with the light and dark distribution condition of interference fringes produced by the interference between a measuring light beam and a reference light beam. A part of the light from a light source is projected as a measuring light beam to a surface to be measured and its reflected light beam from the surface to be measured is superimposed on a reference light beam separately derived from the source light on a two-dimensional sensor. Arranged obliquely between the light source and the surface to be measured is a flat mirror formed therethrough with a pinhole for producing a spherical wave upon the passage of the light source therethrough. A spherical wave of light diffracted and emitted from the pinhole of the mirror is used as the measuring light beam. Also, the spherical wave produced by diffraction from the pinhole is also used for the reference light beam.

Abstract: A reflecting imaging optical apparatus comprises a reflecting spherical optical system including a first spherical reflecting optical system and a second spherical reflecting optical system, and a spherical reflecting mirror disposed near the position of an intermediate image formed by the reflecting spherical optical system. The first and second spherical reflecting optical systems form concentric optical systems, respectively.

Abstract: An illumination device forms a secondary light source having N spots by vibrating a laser beam having a wavelength .lambda. emitted from a pulsed laser by a vibration mirror having a swing angle .theta..sub.0, and irradiates an object to be illuminated through a plurality of lens elements arranged at a spacing d. Those elements meet relations ofd=m.(.lambda./.theta..sub.0)N.(.lambda./.theta..sub.0)>M.dwhere M is the number of lens elements in a predetermined array direction of the plurality of lens elements included in at least a spatial coherent area and m is any integer. Light intensity of the pulsed laser illumination is adjusted such that a total light intensity of the laser beam having pulses satisfying the above relations is equal to a light intensity required for the object to be illuminated.

Abstract: A Fresnel lens provided in the finder of a camera includes a central portion through which an optic axis passes, and a plurality of annular portions spaced apart from the central portion and disposed concentrically. The central portion and the plurality of annular portions have their respective focal lengths. The focal length of the central portion is shorter than the focal length of one of the annular portions which is remotest from the optic axis.

Abstract: An apparatus includes a means for providing a predetermined frequency difference between two light beams and generating an optical beat with respect to interference between first and second diffracted light beams from a diffraction grating formed on a substrate, and a means for detecting a phase difference between the optical beat and a reference signal having a frequency corresponding to the frequency difference between the two light beams, and detects a position of the substrate based upon the phase difference in accordance with an optical heterodyne interference method.

Abstract: A focusing screen in a split image coincidence type range finder provided with an objective lens forming an imaging plane comprises a plurality of light diffusing portions each of which has a surface inclined with respect to the imaging plane. A number of minute depressions or projections are formed on the inclined surface. The depressions or projections are arranged in the form of a matrix along a first direction and a second direction intersecting each other and symmetrical with respect to a fixed direction parallel to the inclined surface and the imaging plane. Each of the depressions or projections is of a pyramidic shape having as the base a parallelogram having first and second sides parallel to the first direction and third and fourth sides parallel to the second direction and extended in the fixed direction. Each of the depressions or projections is arranged so that each side of the parallelogram is common to a side of another adjacent parallelogram.

Abstract: An electronic camera comprises an imaging optical system, image-pickup means for converting an optical image formed by the optical system into an electric image signal, memory means capable of recording the electric image signal, trigger means adapted to be actuated for transferring the electric image signal corresponding to a still optical image to the memory means and means for inserting data into the electric image signal thus transferred. The inserting means comprises means for replacing a part of the recorded electric image signal with "framed" or "unframed" data.

Abstract: Electronic camera comprises an image taking unit and a memory unit connected detachably. The image taking unit generates image signals corresponding to an object. The image signals are transmitted to the memory unit to be stored therein. The memory unit is detached from the image taking unit and connected to an external memory device such as a video tape recorder. The image taking unit has a monitor which can display the image signals in visual form before recording them in the memory unit.

Abstract: An electronic photographic camera includes an imaging optical system operable to be focused to an object to be photographed, a solid state imaging sensing device including a plurality of light-receiving elements disposed in the imaging plane of the imaging optical system and capable of producing a charge corresponding to the quantity of incident light and accumulating the charge therein, first transfer means having a first output terminal and adapted to transfer the charge accumulated in each of the elements separately to the first output terminal, and second transfer means having a second output terminal and adapted to transfer the charges produced in some or all of the elements collectively to the second output terminal, and metering means for measuring the brightness of the object from the charge transferred by the second transfer means.

Abstract: A focus condition detecting device comprises an image forming optical system for forming a light image of an object on a fixed focal plane, an element for separating a pair of light beams from the light beam from the object, a first and a second photoelectric converting element array disposed in the pair of light beams, a first function generator for generating a first function output and a second function output, a first multiplier for putting out the sum of an output resulting from multiplying the first photoelectrical output of the first photoelectric converting element array by the first function output and an output of the second photoelectric converting element array by the second function output, a first integrator for integrating the output of the first multiplier, a second function generator for generating an output equivalent to an output resulting from differentiating one of the first photoelectrical output and the first function output, a second multiplier for multiplying the other of the first ph

Abstract: An apparatus includes a means for providing a predetermined frequency difference between two light beams and generating an optical beat with respect to interference between first and second diffracted light beams from a diffraction grating formed on a substrate, and a means for detecting a phase difference between the optical beat and a reference signal having a frequency corresponding to the frequency difference between the two light beams, and detects a position of the substrate based upon the phase difference in accordance with an optical heterodyne interference method.