Abstract: The present invention is with respect to a reflectance measuring head that is designed for stopping the production of false readings by regular (as opposed to diffuse) reflection and shiny parts of the sample without using normal shine traps or diaphragms. False readings as produced by regular reflection, by surface grain or structure and by inhomogeneity of the surface of the sample are furthermore put an end to by having a number of transmitters placed at an equal distance from one receiver or having a number of receivers placed at an equal distance from a transmitter. A more specially useful effect is produced if a number of transmitters and a number of receivers are placed alternately in the form of a matrix.

Abstract: Optical measurement apparatus, for example for the measurement of displacement, comprises a radiation source 2 coupled to an optical fibre 1 connected to a sensing head 12 comprising a Y-coupler 8 supplying an optic fibre tip 5 and a parallel path incorporating a delay 10 and terminating in a tip 11. A lens 4 of appropriate focal length is positioned between tip 5 and a reflector 3 to focus light onto reflector 3 so that the amount of light reflected back to tip 5 is a function of the position of the reflector. A signal detector 6 is also coupled to fibre to detect and measure the reflected light. Tip 11 is positioned at the focus of lens 4 so that the light reflected back to tip 11 is independent of the position of reflector 3. The ratio of the two reflected signals detected in detector 6 is calculated to give the position of reflector 3 with compensation for the effects of deterioration of the parts of the apparatus in which there is a common path for the two quantities of light.

Abstract: A method of nondestructive testing of the surface of an object using vapor condensation, such as sputtering, evaporation, or gas disassociation, to lay a thin solid film upon the surface of the object to be tested. The film is either highly reflective or highly absorptive. Portions of the solid film are then removed from the surface, for example, by abrasion while the remaining coating material is in a pattern depending on anomalies. The surface is then irradiated and inspected under light and the differential reflection between the remaining coating material and the surface itself enhances the visibility of the crack or other surface characteristic. The technique is especially useful for detecting very small cracks in cutting or grinding implements made of compacted material.

Abstract: The present invention relates to an optical system of a radiation thermometer in which the measuring optical system and the finder optical system can be focused. The central portion of the sub-mirror in Cassegrainian type optical system is used as a finder lens of the finder optical system. The third mirror is located between the main and sub-mirrors in order to reflect the light passed through the central portion of the sub-mirror. The light reflected on the third mirror is used for finder observation.

Abstract: In a method for detecting an inferior container, wherein: light beams are projected in different two directions upon a side of a transparent or a semitransparent test container while the container is rotatably driven; both of a transmitted beam which is one of the above light beams, having penetrated through the container, and a refelected beam which is the other of the above light beams, having reflected from the container are simultaneously received by a common photo-receptive surface; a composite image constructed of both of the transmitted beam and the reflected beam is projected upon this photo-receptive surface; and an inferior container is detected by means of a shadow formed in this image.

Abstract: An autoalignment system for an unstable laser resonator includes means for measuring the angular position of a convex mirror and adjusting the concave mirror to a new optic axis defined by the convex mirror.

Abstract: A device for sensing the longitudinal edges of an aperture pattern in a longitudinally and transversely moving opaque strip of material includes a transversely moveable platform. Arrays of detector elements are supported on the platform and positioned such that some elements of each array are opposite the aperture patterns and other elements of each array are opposite the opaque borders of the strip. Energy sources are individually arranged on the side of the strip opposite the arrays whereby the elements opposite the aperture pattern receive energy and the elements opposite the borders are shielded. The energy conditions of the elements are detected and the platform is moved transversely to maintain an equal number of elements in both arrays opposite the apertures whereby the platform tracks the transverse motion of the strip.

Abstract: Described is a method for facilitating the alignment of a photomask with individual fields on the surfaces of a number of wafers onto which fields the pattern of the photomask is to be imaged for projection printing, each of said number of wafers carrying an identical array of fields produced in at least one previous printing process. For this purpose it is possible to choose one out of the identical batch of wafers, measure the rotational adjustment necessary to bring each field into the correct direction in the horizontal plane and to use the measured value for an automatic rotational adjustment of all other wafers of the batch.

Abstract: The relative transverse position of a measuring device and the aperture patterns in a longitudinally and transversely moving strip of material is held constant. A platform, which supports the measuring device, moves transversely along with the strip. Multi-element energy sensors are supported on the platform at the longitudinal edges of the pattern. Different numbers of elements are illuminated when the strip is off center and a difference signal is provided. The difference signal is used to move the platform to maintain the desired constant transverse relative positioning.

Abstract: An optical detector assembly comprises a casing formed therein with a through bore having front and rear openings and a pair of opposite cavities located at both sides of the through bore, an air duct member disposed within the through bore to permit the flow of air passing therethrough, the duct member being formed at its peripheral wall with a pair of radial holes opening toward the cavities respectively, a light emission element arranged within one of the cavities to emit a luminous ray and pass it through the radial holes of the duct member toward the other cavity, a light receiving element arranged within the other cavity to receive the luminous ray emitted from the light emission element and passed through the radial holes, and an air induction assembly coupled over the front opening of the through bore for preventing entry of alien particles such as dirt, water, snow and the like into the duct member.

Abstract: The invention relates to a method and an apparatus for calibrating a positioning system, including control means (209) sending command signals to the positioning apparatus (204) intended during a working state to locate an object (203) in relation to an operating area (206), the situation of the apparatus being sensed and converted to an actual value signal which is sent to the control means. The positioning apparatus has a working state which is interrupted at given intervals by a calibrating state, during which the positioning apparatus is accurately put in register with at least one detector (208), situated within the operating area in a given position. The output signals from the detectors are allowed to activate the control means, whereafter the actual value signal is determined and the positioning apparatus calibrated in response to the determined actual value signal.

Abstract: An apparatus for aligning objects on the basis of a signal obtained by scanning marks formed on the objects. A position datum representing the relative position between the objects is extracted on the basis of an extraction level. The marks are scanned a plurality of times and an average is obtained by the plural data provided on the basis of the extraction datum. Those operations are repeated with one or more different extraction levels. In each of the data group corresponding to one of the extraction data, a peculiar or exceptional datum is determined. Among the peculiar data obtained for individual sets of data, a minimum is selected. Thus, an extraction datum which results in the minimum peculiar datum is determined. The average of the position data obtained with this extraction datum is used for bringing the objects into alignment with each other.

Abstract: A readhead with reduced height sensitivity for use in a reflectance photometer that measures reflectance of diffuse light from a sample disposed outside the readhead includes a housing with an upper spherical portion and a lower conical portion. The inner peripheral surface of the upper portion is hemispherically configured and the inner peripheral surface of the lower portion is conically configured to permit illumination of a sample disposed outside the readhead. The angle of the cone defined in the conical portion of the housing is in the range of 45.degree.-60.degree.. The inner peripheral surfaces of the upper and lower portions are coated with a highly reflective material, such as barium sulfate. The apex of the conically configured housing portion is truncated to provide a light transmitting aperture for sample illumination. A sample is positioned adjacent the light-transmitting aperture below and outside the conically shaped readhead housing portion.

Abstract: A pattern of light is projected upon a surface to be measured which may be devoid of surface detail. A sharply focused image of the surface provides distance discrimination. Although the projected pattern may be separate from the imaging optics, a common optics path removes distortion, provides maximum sensitivity and eliminates processing for misalignment between projector and imager. Sequential cross-correlation, synchronous detection or percent modulation processing methods may be readily implemented to develop three-dimensional coordinates relative to the sensor for all in-focus regions of the image. Refocusing the lens provides depth coverage. The amount of data can be increased by adapting the projected pattern to produce a maximum of detail in the direction of minimum rate of change of depth of the surface being measured.

Abstract: An observation device usable with an apparatus for aligning two members each having alignment marks. The device includes an optical path for the beam reflected by the alignment marks, which at least partially is not common with an optical path for the beam directed to the alignment marks. In the uncommon optical path for the scanning beam or for the reflected beam, there is a 90 degree image rotator to provide, in the observation view field, a scanning direction which is traverse to a direction connecting the alignment marks, thus enabling an operator to observe images in natural forms.

Abstract: A mask aligner includes a photo-mask having a plurality of first marks used to align the photo-mask with a wafer and a plurality of second marks used to align the photo-mask with the mask aligner, the number of the second marks being equal to that of the first marks; a wafer having a plurality of third marks associated with the first marks; a mark providing section having a plurality of fourth marks associated with the second marks; and a detector for detecting an error in alignment between the first and third marks and also an error in alignment between the second and fourth marks, the detector including a plurality of sensors for sensing various marks in different positions, a basic form produced when the first and third marks are placed one above another being substantially the same as that produced when the second and fourth marks are placed one above another.

Abstract: A method of monitoring the deflocculation of particles in a suspension, which particles, when deflocculated, are such that they can become aligned in an applied field, comprises applying a beam of radiation to a region of the suspension, applying a field to the region and detecting a change, if any, in radiation scattering properties of said region due to the aligning of deflocculated particles, if any, of the suspension in the field, wherein said suspension is passed through a cell which is transparent to said radiation and provides said region in which said field is produced and on to which region said radiation is applied and wherein said suspension is pumped through said cell and the field is applied in bursts timed with the pumping operation.

Abstract: A rotating analyzer type ellipsometer comprises a rotating analyzer for receiving light which is impinged on a sample with a predetermined incident angle and reflected by the sample, a rotary phase detecting apparatus provided so as to rotate unitarily with the rotating analyzer for generating a rotary phase signal as the rotary phase detecting apparatus rotates, a rotating mechanism for rotating the rotating analyzer and the rotary phase detecting apparatus, a photodetector for producing an output responsive to light which is passed through the rotating analyzer, and a computer for obtaining a phase difference between the rotating analyzer and the rotary phase detecting apparatus from a phase difference .phi..sub.o with which a difference between an output I.sub.p of the photodetector and a theoretical value I.sub.o becomes a minimum or substantially zero by entering into the computer the output I.sub.p of the photodetector and calculating the theoretical value I.sub.

Abstract: An autocollimation method and apparatus are disclosed wherein a primary image of the reticle and a secondary image of the primary image which has been telescopically directed to and reflected from a remote reflecting surface are superimposed on a video display. The primary image of the reticle is produced along a first optical path and the secondary image of the reticle along second optical path including Cassegrainian focusing telescopic optical elements. The optical paths are provided with a commonly shared portion for alternatively positioning means of different optical magnification. Alternative magnification are provided for producing first and second images on the video display for first coarse and then fine determinations and/or adjustments.

Abstract: An optical circulator comprising a first optical path and a second optical path formed between a first polarizer prism and a second polarizer prism, Faraday rotators interposed in the first and second optical paths, the polarizing direction of the Faraday rotators being rotated by an angle of 45.degree. by a magnetic field and the direction of polarizing rotation being reversed with respect to the propagation direction of light which passes therethrough, and polarizing direction rotators interposed in the first and second optical paths, the polarizing direction of the polarizing direction rotators being rotated by an angle of 45.degree. and the direction of polarizing rotation not being reversed with respect to the propagation direction of light which passes therethrough.