Abstract: An automatic focusing control method for microscope includes preliminarily determining and storing respective in-focus positions of an objective lens of the microscope for a plurality of points on a stage of the microscope prior to observation and measurement of a sample by the microscope. Upon actual measurement after the sample has been mounted on the microscope stage, an approximate in-focus position of the objective lens for the sample is determined on the basis of the stored in-focus positions of the objective lens for at least one of the plurality of points in the vicinity of the sample. Then, the objective lens is moved to the determined approximate in-focus position at a high speed, and a usual automatic focusing is thereafter carried out, thereby making it possible to perform the automatic focusing operation rapidly and accurately.

Abstract: Process and apparatus for focussing of an optical display system in which the total of the light intensities for all the adjacent picture elements is added up and in passing through the focus area the maximum is determined from the total for a specific focussing which is then defined as focus plane, and in the adding up of each total by a preselection of the supplied signals only those brightness differences of adjacent picture elements are taken into account which make positive contributions to the adding up. The adding up and preselection is carried out by a computing device operating on an electronic basis for computing the total ##EQU1## in which x is the line position of a picture element, y the column position of the picture element, I.sub.x,y the intensity of the picture element, M the number of lines of the image and N the number of columns of the image.

Abstract: An astigmatism generator such as may be used in the pickup of an optical disk player which produces substantially no other aberrations yet which can be manufactured at a low cost. The astigmatism generator is fabricated from a plate having four plane surfaces, including a first surface through which light is introduced, a second surface parallel to the first surface and through which the light exits, and a third surface by which light transmitted through the first surface is reflected toward the second surface. The third surface is arranged at an oblique angle to the first and second surfaces and is selected such that almost all coma is eliminated from the light passing through the second surface.

Abstract: A magneto-optic optical disc system which uses the magneto-optic differential data detection channel, with addition only a low pass filter, to also detect focus error. The differential data detection channel includes a pair of photodetectors, the first photodetector being located a predetermined distance within the focal length of the detector lens associated with that photodetector and the second photodetector being located beyond the focal length of the detector lens associated with that photodetector. The output of a differential amplifier receiving the photodetector outputs is the data signal and the output of a low pass filter connected to the output of the differential amplifier is the focus error signal. The dual functionality of the differential data detection channel eliminates a separate optical focus channel, and relative to separate astigmatic focus and data detection channels elmininates a quadrature detector, several optical elements, several electrical elements, and the space they occupy.

Abstract: Light intensity distributions of object images whose relative positions vary with a focusing state of an objective lens are formed by a lens assembly based on light fluxes transmitted through the objective lens, and the distributions are sensed by sensing devices having a plurality of photo-sensors to produce first and second signals for the respective light intensity distributions. The first and second signals are processed by relatively displacing the first and second signals under a first relationship and by relatively displacing the first and second signals under a second relationship different from the first relationship to determine a relative positional relationship of the light intensity distributions. If there is identical or essentially identical portion is found in the processing of the first signal and the second signal, the previous processing result is utilized to shorten the processing time.

Abstract: A focus detecting apparatus in which light distributions having their relative positional relation varying in conformity with the focus adjusted state of an objective optical system and based on an object are received by a light-receiving device having a plurality of picture elements and the output signal of the light-receiving device is operated in two different processes, and an evaluated values dependent on the contrast is operated in each of the processes and the evaluated values are compared with each other, and the result calculated in the process of better contrast is adopted as a value indicative of the focus adjusted state of the objective optical system.

Abstract: Present invention relates to a phase difference detection type focus detecting device which includes a pair of image forming lenses and a photo sensor array and detects the focus deviation in accordance with the positions of a pair of formed images respectively formed on the photo sensor array by the pair of image forming lenses. In such focus detecting device, the pair of image forming lenses are integrally molded of a plastic material, such that the change of the distance between the pair of image forming lenses due to the temperature change causes the error of the focus deviation. The error is made to zero by the detection of the ambient temperature and the compensation of the data basing on expansion or contraction of the plastic material with temperature.

Abstract: In a focus detection system for detecting focus condition of an objective lens, there is disposed a pair of photo sensor arrays each having a plurality of photo cells lined up in one direction to receive a first image and second image passed through respectively a lens system and the photo sensor arrays produce first original signal groups and second original signal groups each signal groups corresponding to light intensity of the images projected thereto. A processing device processes the original signal groups in such a manner that the first original signal groups are respectively divided into a plurality of blocks, and one of the blocks of the first original signal groups is selected and it is detected that in what group in the selected block best coincidence occurs.

Abstract: A deviation detecting device comprising an optical system for forming correlated first and second images of an object; first and second image sensors for sensing the first and second images so as to generate first and second outputs representative of the intensity distributions thereof, respectively; a correlation detector for shifting the first output relative to the second output while incrementally changing the amount of shifting so as to detect a plurality of correlation degrees representative of the degrees of the correlation between the first and second outputs at different shift position defined by the incremental change in the amount of shifting; a highest correlation shift position detector for detecting the shift position which is defined by the amount of shifting providing the highest correlation degree; a calculation unit for calculating, based on the shift position detected by highest correlation shift position detector, data corresponding to the amount of deviation of the first and second images

Abstract: In the disclosed automatic focus detecting device for an imaging optical system a light spot is projected onto an object and an image of the object is formed on a predetermined focal plane. A light receiving photo-sensitive element produces at least two signals according to the position of the reflection of the projected light spot. A comparator detects when the relation between the integrated values of outputs of the light receiving element exceeds a predetermined level. A detector means detects when the light spot image has been projected for a predetermined time and a determining arrangement determines the focus of the imaging optical system on the basis of the outputs of the light receiving element when at least either the comparator or time detector detects the predetermined level or length of time.

Abstract: This specification discloses a distance measuring apparatus and method in which two-dimensionally arranged light-receiving elements are used as illumination distribution measuring means, the correlation between the illumination distributions of the images of an object on the set of certain portions of the respective measuring means is taken to thereby calculate the distance to the object present in a certain direction corresponding to the set, and the calculations are effected with respect to a plurality of sets portions of the respective measuring means to thereby calculate the distances to objects present in a plurality of directions.

Abstract: An improved apparatus for automatic focusing of a lens system, including a space dissector (17) for analyzing the space frequency components of the image planes close to the ideal focus plane, and devices (53, 57) for detecting the position of the plane at which the maximum of space frequencies occurs, close to the ideal focus plane. An electronic device is provided for obtaining a suitable signal from said space dissector (17), to provide an adjustment control signal actuating a servo-control unit controlling the lens focusing, and for thus leading to the image plane having the maximum of high frequency components being placed in coincidence with the ideal focus plane.

Abstract: Method and apparatus for detecting a focus condition for an optical system sequentially forms two images of an object, the images propagating along two different optical paths. The two images are sequentially received with a plurality of photosensitive elements. The photosensitive elements are disposed in a plurality of sections, each section having a plurality of elements, each element outputting a signal corresponding to received light. The element output signals from the first image are stored in a first memory, while the element output signals from the second image are stored in a second memory. A processor calculates the image light contrast for each section from the stored element signals. Then, the section displaying the highest contrast is selected for use in the correlation process. The correlation process is carried out by correlating the stored first image element signals with the stored second image element signals from the selected section.

Abstract: An apparatus for detecting a focused condition of an optical system, in which a light-receiving means arranged at a fixed position corresponding to a focus position photometrically detects a focused condition. A light beam having a definite shape is projected onto an object to be imaged by a light projection means. The reflected light beam is conducted along an optical axis of the optical system, deflected, and detected by the light receiving means for determining whether a focused condition exists. Several embodiments are disclosed for projecting a light spot of high contrast on the object and for detecting a focused condition on the basis of the intensity distribution of light received by the light-receiving means. The apparatus may be applied to an endoscope and other optical systems.

Abstract: A method of auto-focusing suitable for fine patterns of LSIs and an apparatus therefor, particularly applied for checking the geometry of a circuit pattern of a semiconductor device formed on an LSI wafer. A stripe pattern is projected on a specified location on an object to be checked and contrast of an image of the stripe pattern is used for focusing. The specified location is imaged by an optical system and detected simultaneously by two detectors. A position at which contrast of an output signal of one detector coincides with that of the other detector is determined to be an in-focus position. Am image of a multi-layer pattern representative of the circuit pattern is focused on another detector disposed at the in-focus position and detected for checking. The output signal of the detector is divided by mean brightness of the stripe pattern image so as to be normalized.

Abstract: A focus detecting device arranged to detect the focusing condition of an objective lens by projecting a light flux from a light source onto an object through the objective lens and by sensing the light flux after it is reflected from the object. The focus detecting device is provided with sensors which produce information necessary for detecting the focal point of the objective lens by sensing the light of the light source reflected by the object. Degradation of the device's detection accuracy due to the eccentrically mounted objective lens is prevented when these sensors are symmetrically arranged relative to a plane containing the optical axis of the objective lens.

Abstract: A method and apparatus for detecting the focus state of an object image pattern in accordance with a plurality of photo-electrically converted output signals, including a first mode in which the plurality of photo-electrically converted output signals are sampled at different times and statistically processed for each output, wherein the focus state is detected in accordance with the statistically processed outputs, and a second mode for detecting the focus state without the statistical processing.

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: An apparatus for detecting a focused condition of an optical system, in which a light-receiving means arranged at a fixed position corresponding to a focus position photometrically detects a focused condition. A light beam having a definite shape is projected onto an object to be imaged by a light projection means. The reflected light beam is conducted along an optical axis of the optical system, deflected, and detected by the light receiving means for determining whether a focused condition exists. Several embodiments are disclosed for projecting a light spot of high contrast of the object and for detecting a focused condition on the basis of the intensity distribution of light received by the light-receiving means. The apparatus may be applied to an endoscope and other optical systems.

Abstract: An apparatus for detecting the shake of an image of an object, having first and second photosensor arrays for detecting an image of an object in two different directions, a signal processor for processing output signals from the first and second photosensor arrays and for producing a focusing control signal of an objective lens, a memory circuit for storing an output signal from the first photosensor array, and a discrimination circuit for discriminating the shake of the object in accordance with the signal stored in the memory circuit and a signal from the first photosensor array produced subsequent to this signal.

Abstract: In an apparatus for detecting a focusing state of an optical system, a laser beam generated from a laser unit is transmitted through a beam splitter to a convergent lens. The laser beam is converged by the convergent lens and projected toward the surface of an optical disk. The laser beam reflected from the disk surface is reflected by the beam splitter and projected through the aperture of a light shielding plate to a photodetector. The photodetector has first and second photo sensitive regions arranged concentrically, and when the convergent lens is in a focusing state, the levels of the first and second photo signals from the first and second photo sensitive regions are equal to one another, and the output signal from the differential amplifier is maintained at zero level. When the convergent lens is approaches the focusing state from the position sufficiently separated from the optical disk, a positive output signal is generated from the differential amplifier.

Abstract: An apparatus and method for detecting focus condition of an imaging optical system is disclosed.

Abstract: An optical distance measuring system which utilizes binocular optics with a mosaic sensor to simulate stereo imaging so that distance can be determined by noting the apparent displacement between left and right images in the stereo pair. The binocular optics comprise spaced shutter mechanisms which are alternatively actuated, the first such image information on the sensor being stored for ultimate comparison with information from the sensor as obtained through the other shutter mechanism, such compared information enabling distance or depth to be determined through the use of appropriate mathematical equations.

Abstract: A focus detection system includes an object lens for focusing an image of an object, a refocusing optical system for refocusing a plurality of component image having parallax from the image of the image, a view field mask arranged between the object lens and the refocusing optical system and having a laterally extending aperture, and a sensing device having a photo-sensor array for sensing the component images. Focus detection error is prevented by determining a sense area of the photo-sensor array in accordance with a distortion created in an aperture image by the refocusing optical system.

Abstract: In automatic focusing devices of the type which detect a defocus degree and a focusing direction and according to the results of detection, automatically shift a lens to an in-focus position, an accurate defocus degree cannot be obtained when the lens position is far away from an in-focus point. In such a case, focus detection must be carried out by driving the lens in the focusing direction solely according to information on the focusing direction, which, because of a weak signal from the detection output necessitates a slow lens driving speed and accordingly takes a long time for shifting the lens position to an in-focus point. Another problem with conventional devices is the possibility of overshoot which happens while bringing the lens to the in-focus point by driving it to a defocus degree. Then, after such anovershoot, the lens is again driven to the defocus degree in the reverse direction. This results in a second hunting which tends to occur before the in-focus position is attained.

Abstract: In the disclosed distance measuring device a light source projects a light on an object to be photographed and at least two photo-electric converters each with several light receiving areas receive light reflected by the object. The quantity of electric charge on these areas varies with the quantity of light incident thereon. An electric charge storage stores the electric charges produced at the two converters and a control determines the operation of the light receiving areas of the photo-electric converters according to the electric charge information produced.

Abstract: A focus detecting device for detecting the focus adjusted state of an imaging optical system with respect to an object body comprises first and second photoelectric element arrays each including a plurality of photoelectric elements arranged in one direction, a focus detecting optical system for forming first and second optical images of the body on or near the first and second arrays by first and second light beams passed through different first and second areas, respectively, of the exit pupil of the imaging optical system, the first array producing a series of first output signals having a distribution pattern associated with the illumination intensity distribution pattern of the first image, the second array producing a series of second output signals having a distribution pattern associated with the illumination intensity distribution pattern of the second image, focus detection means for producing a focus detection signal representative of the focus adjusted state of the imaging optical system, on the b

Abstract: An autofocusing microscope includes a spot marker assembly for projecting a spot marker on the sample surface. The image of the spot marker is continuously scanned while the objective lens is moved along a preselected range of distances from said sample surface. The lens is then moved to the optimum focusing in accordance with the scanning.

Abstract: In the disclosed automatic focus adjusting device of the active type having a light emitting element for projecting light for focus detection onto an object to be photographed, light emitting operation and non-light emitting operations of the light emitting element are periodically effected, and the duty ratio or frequency of the light emitting period is variable.

Abstract: This specification discloses a focus detecting system in which a plurality of images are formed on the basis of light beams passing through different portions of the pupil of an objective lens and the focus state of the objective lens is detected from the relative positional relation of these images and wherein filters of which the density distribution varies along the direction of arrangement of photoelectric conversion elements are disposed in front of photoelectric conversion element arrays for detecting the distributions of quantity of light of the images, thereby accomplishing shading correction.

Abstract: Disclosed is an automatic focusing system for optical imaging equipment, such as a camera, which includes a relative image displacement detection system providing first and second digital quantities indicative of the direction in which the focus of the imaging system is to be altered to achieve focus and the magnitude of such alterations, respectively, and an image contrast detection system providing a third digital quantity indicative of the change in the contrast of an image formed by the imaging system as the focus thereof is altered. In addition, the apparatus includes a servomotor for altering the focus of the imaging system and a motor control circuit which receives the first, second and third digital quantities and provides motor control signals to the servomotor.

Abstract: In an optical head, a laser beam emitted from a laser unit is converged by an objective lens and is projected toward a light reflecting layer of an optical disk. The laser beam reflected by the light reflecting layer is directed toward a light shielding plate through the objective lens. One part of the laser beam is shielded by the light shielding plate, and the other part thereof is converged by the projection lens and is projected on the photo sensitive regions. When the objective lens is kept in the just in-focusing state, a differential signal between photo signals generated from the photo sensitive regions is maintained at zero level. The differential signal is set at zero level when the objective lens is located at a transition point corresponding to a distance .delta.tf within the defocusing range. The beam spot formed by the light beam when the objective lens is located in the transition point extends outside the photo sensitive regions.

Abstract: In a focus correction servo loop which maintains optical focus on an optical disk by movement of an objective lens, a focus error signal generating system which utilizes a pair of photodetectors in a differential channel, the first detector being located a predetermined distance within the focal length of the detector lens associated with that detector and the second detector being located beyond the focal length of the detector lens associated with that detector by the same predetermined distance. When the disk is at the focal point of the objective lens, equal light will fall on both detectors. When the disk position deviates from the focal point of the objective lens, more light will fall on one detector than on the other detector. The dc value of the difference between the detector signals is the focus error signal utilized by the servo loop.

Abstract: A focusing apparatus for projection optical system is provided with a projection optical system and an image-forming optical system. The projection optical system is disposed to project an image of an alignment mark formed on a photo mask or reticle onto a light-reflective substrate and also to reverse-project onto the photo mask the light image of the alignment mark projected on and reflected by the substrate. The image-forming optical system forms an overlap image from the reverse-projected reflected image and the alignment mark on the photo mask.

Abstract: Present invention relates to a phase difference detection type focus detecting device which includes a pair of image forming lenses and a photo sensor array and detects the focus deviation in accordance with the positions of a pair of formed images respectively formed on the photo sensor array by the pair of image forming lenses. In such focus detecting device, the pair of image forming lenses are integrally molded of a plastic material, such that the change of the distance between the pair of image forming lenses due to the temperature change causes the error of the focus deviation. The error is made to zero by the detection of the ambient temperature and the compensation of the data basing on expansion or contraction of the plastic material with temperature.

Abstract: An area-type beam splitter is disposed across the optical path of an imaging optical system. Photodetector arrays are located across the optical path portions divided by the beam splitter. The photodetector arrays in the respective optical path portions are arranged in different positions from one another in such a manner that images different from one another in imaging performance will be read by the respective photodetector arrays.

Abstract: A trigonometric range finding device is provided which detects a focal point by comparing image readout signals of two rows of digital sensors. The range finding device incorporates an optical low-pass filter inserted between the lens and digital sensor rows for lowering the MTF (modulation transfer function) of the spatial frequency component of the image which is higher than the spatial frequency component corresponding to the pitch of the digital sensors arranged in rows, so that erratic operation of the range finding device may be prevented.

Abstract: An automatic microscope focusing system including a light source 44, a dual channel fiber optics bundle 56 and 58, chopper means 54 for alternately admitting light to the channels, a reticle 66 and associated optics to cast alternating images onto the surface of an inspected article W, return masks 82 and 88, and associated detectors 86 and 92 for inspecting the alternating reticle images, and control circuitry 36 and 38 responsive to the detector outputs and operative to drive the system microscope 10 into focus. The preferred embodiment also includes a flipping pupil 60 for accommodating particular microscope objectives.

Abstract: A focus detecting device is provided with first and second line sensors and first and second image forming lenses which are located behind a predetermined focal plane of the objective lens to receive the object lights for forming first and second images on the first and second line sensors, respectively. The image signal generated by the first line sensor is divided into a plurality of block signals each consisting of a predetermined number of picture element outputs and each block signal is compared with groups of picture element outputs of the second line sensor, with the groups shifted sequentially, to find a group which best coincides therewith and the distance between the first and second images on the line sensors is calculated in accordance with the shift position of the group thus determined, for calculation of the amount and direction of defocus of the object image on the focal plane.

Abstract: Less than half of a laser beam reflected from an optical information storage medium through an objective lens is detected by a detector having two light detecting areas. The sum of output signals from the light detecting areas of the detector is employed to detect when the objective lenas enters a focusing range. The difference between the output signals is employed to detect when the laser beam is focused on the optical information storage medium.

Abstract: A control device for automatic focusing includes a low sharpness discriminating circuit for identifying a minimum contrast required for focus detecting function and a correlation zone discriminating circuit for determining whether an object is in or out of a correlation zone in the vicinity of the in-focus position. Output signals are supplied from the two discriminating circuits to a sequence control circuit for determining whether to continue or discontinue operation of a lens driving apparatus for driving the lens. A control device may further include a low brightness discriminating circuit the output signal of which is supplied to the sequence control circuit to immediately discontinue the operation of the lens driving apparatus when the low brightness discriminating circuit identifies a low brightness of the object, regardless of the results of other discriminations.

Abstract: Disclosed is a signal accumulating time control method for a signal accumulating type radiation sensing device which produces an electrical signal corresponding to the amount of incident radiation and accumulates the same. According to the improvement of the present invention, the accumulating time is controlled by successive approximation at different intervals when there happens a situation in which the accumulating time must be changed greatly.

Abstract: An automatic focus detecting device comprising a photoelectric converting device formed by arranging many elements, a pupil divider capable of forming two object images on the photoelectric converting device through different light paths, a device capable of detecting an in-focus position by processing two image data obtained as output signals from the photoelectric converting device, a device for determining the reciprocal numbers of the output signals obtained by applying a uniform light onto the photoelectric converting device and a device for receiving the image data to correct the signals for output multiplying the image data by these reciprocal numbers in order to enable accurate focusing. The photoelectric converting device is so arranged as to receive the light having passed through an infrared cut filter or a band pass filter.

Abstract: A focusing device for optical systems provided with a rotatable light interrupting plate having a first light passing zone and second light passing zone, an image sensor receiving two kinds of images formed by light bundles having passed through the light interrupting plate and converting the respective light intensity distributions to photoelectric signals, a central operation circuit digital-converting the photoelectric signals from the image sensor, then operating them according to a predetermined evaluating function and able to display the state of focusing and the amount and direction of deviation from the focus position and an image information processing circuit able to feed only proper photoelectric signals from the image sensor to the central operation circuit, in order to be able to detect accurately and with a high sensitivity whether focusing is made or not and to detect the amount and direction of deviation from the focus position.

Abstract: A focus detecting method and its apparatus arranges two rows of photoelectric transducer elements in positions optically equivalent to plane position which are located before and behind a presumed focal plane of an image forming optical system, respectively, divide a light beam into a first light beam passing through a first half portion of an exit pupil and a second light beam passing through a second half portion of the exit pupil by a shift generating optical system, primarily receive one of said first and second light beams on at least one of said first and second rows of transducer elements and primarily receive the other of said first and second light beams on at least the other of said first and second rows and performs a focus detection based on shift or displacement of images which is caused by said first and the second light beams on said first and second rows of transducer elements.

Abstract: An automatic focusing device for vertical focusing of a specimen 23 in which an enlarging condenser lens 11 is placed between a light source 12 and a half mirror 7 in an automatic focus detecting system so that an enlarged image 24 of the light source is presented to an objective 1 of the focusing microscope M.

Abstract: In an apparatus wherein on the basis of a light passing through an objective lens, a plurality of images whose relative positional relation varies in accordance with the focus state of the objective lens are formed and these images are detected by photoelectric conversion element arrays and a predetermined operation is effected by the use of a plurality of photoelectrically converted signals obtained correspondingly to the respective images to thereby detect the focus state of the objective lens, there are provided first adder means for comparing the photoelectrically converted signals of the respective images in a predetermined relation and adding the smaller signal and second adder means for comparing the photoelectrically connected signals of the respective images in a predetermined relation and adding the greater signal and focus detection is effected by utilization of the result of the addition of one of the first and second adder means in accordance with the object condition, whereby accurate focus dete

Abstract: When the disclosed automatic focusing device detects that a computed distance measurement is inaccurate, it shifts the lens a predetermined length to a new position for another measurement. A system senses when the inaccuracy arises from an overly dim scene, for which a distance cannot be properly measured in any case, and inhibits the successive shifts to avoid waste of energy.

Abstract: In a method for detecting a focus condition which utilizes an image lateral shift between images formed alternately on light receiving elements substantially arranged on a focal plane, an incident light unbalance on the light receiving elements caused by an image height effect for respective light receiving elements and a relative positional shift between a pupil dividing means and the light receiving element is corrected by using correction coefficients previously stored in a digital memory. The correction coefficients for respective light receiving elements are derived from inversion outputs of respective light receiving elements under the condition such that a uniform light flux is projected onto the imaging optical system before effecting an actual focus detecting operation. It is possible to make the optical system small in size and inexpensive in cost, because it is not necessary to use an additional optical system.

Abstract: An automatic focusing device and method for a camera in which the distance and direction to the focused position of a focusing lens of the camera are quickly determined after which the lens is moved directly to the focused position without the necessity of carrying out calculations as the lens is moved. Images of an object being viewed through the lens are projected onto first and second sensor groups. The outputs of the sensor groups are digitized then calculations are performed to determine the distance and direction to the position of correct focus. The lens is then moved to the focused position directly in accordance wtih the computed values.