Abstract: The calibration scheme disclosed herein is applicable to microlithographic systems of the type in which alignment between successive exposures is provided by means of a microscope mounted to one side of the optical projection column, there being a laser metered stage for transporting a semiconductor wafer between the microscope and an optical projection column. In accordance with the practice of the invention, a wafer with a light sensitive coating is placed on the stage and transported to the column using an approximate base line value. After exposure from a reticle which includes fiducial markings, the wafer is transported by the stage to the microscope. By observing the latent image on the coating, the precise stage movement required to align the latent image of the fiducial markings on the wafer with the microscope system reference reticle may be measured with the laser metered stage. The base line value is then corrected based on the actual measurement.

Abstract: A system and method for determining modulation transfer function (MTF) of an optical element or system employs a moire deflectometer. A selected central portion of monochromatic light is directed to the first grating of the moire deflectometer through or from the optical system, resulting in a moire pattern in which the contrast along an axis incident to the moire fringes is indicative of the MTF of the optical system for a particular spatial frequency, which is dependent on the spacing between the gratings of the moire deflectometer.

Abstract: A method of visually monitoring the change in dimensions of elements on a surface of a semiconductor body during processing is provided. A fixed pattern of scale images on the surface with a predetermined distance between images, together with a wedge-shaped element is provided on the surface. The wedge element has an apex adjacent one of the images and extends in a direction along other ones of the images. The semiconductor body is processed and the dimensions of the wedge-shaped element (as well as the scale image) change. One may then subsequently visually inspect the wedge shaped element with respect to the pattern of images to determine the extent of the change in dimension of the wedge shaped element during processing.

Abstract: A lens meter having a focusing indication system with divided-image registration focusing comprises a condenser lens, a target having a nondiffusing transmissive surface and a slit pattern thereon, an objective lens, a lens mount for supporting a lens to be examined, a projection lens, a screen, the arrangement being such that the distance of movement in unison of the condenser lens and the target in the direction of an optical axis is read to detect the degree of the lens supported on the lens mount, an aperture plate disposed in the vicinity of a front focal point of the condenser lens and movable with the condenser lens and the target in the direction of the optical axis, and at least two deflection prisms disposed in intimate contact with the slit pattern on the target and having bases extending across the slit pattern and substantially perpendicularly to each other.

Abstract: A scanning unit comprises offset scanning gratings and light receivers disposed behind respective gratings. The scanning unit is moved past an incremental scale and the receivers are illuminated through the scale and the gratings. Carrier frequency signals which are displaced in phase and are amplitude-modulated in dependence on the pitch of the scale are generated in response to the scanning movement. The phase displacement of the modulation of the carrier signal is evaluated to determine the instantaneously scanned fraction of a scale increment in that a proportional number of clock pulses are counted by a counter. The use of a simple and reliable circuit arrangement and a reliable evaluation are permitted in that the illumination is modulated at the carrier frequency so that the light receivers constitute means for effecting an amplitude modulation of the carrier frequency signal. The amplitude-modulated signal is then processed further.

Abstract: An improved method and apparatus for use in photometric testing of high intensity discharge lamps and luminaires is disclosed. The improved apparatus includes the creation of a mock high intensity discharge lamp having an incandescent emitting element replacing the arc plasma of the subject high intensity discharge lamp while carefully duplicating all other structural and electrical details of the lamp. The improved method incorporates the use of the mock high intensity discharge lamp to obtain accurate testing of the photometric qualities of the regular high intensity discharge lamp.

Abstract: The inspection for surface deformation of flat glass is carried out by the flying-spot method wherein the beam of light is thrown by a rotating mirror 13 onto a folding mirror 6 which reflects the light onto the continuous sheet of glass 2 to be inspected. The reflected light beam 4 strikes a light-diffusing plate 1 disposed ahead of the receiver 11. The area of the light-diffusing plate 1 on which the beam of light impinges when the sheet of glass 2 is free of defects is opaque. On this opaque area there are disposed in a spaced relationship two photodiodes 7 between which a light bar formed by the scanning light beam extends. When the thickness of the flat glass 2 varies gradually, light will strike one of the photodiodes 7. The pulse so triggered controls a tracking mechanism 50 which adjusts the folding mirror 6 so that the light bar again extends between the photodiodes 7.

Abstract: Apparatus and method for measuring the density of sperm in a sample and for calculating the magnitude of dose required for artificial insemination. An optical assembly with light source, specimen holder and photodetector providing a signal to an amplifier the output of which is proportional to absorbance of the sample. A signal selection system utilizes three parallel signal channels with each having a different correction factor for matching the absorbance signal to actual density count, and including means for selecting the appropriate signal channel as a function of signal amplitude, with the output when calibrated providing the direct reading of the sperm density. Knowing the number of sperm cells desired per insemination and the percent motility of the sample sperm, the required dose is calculated as a function of the density count.

Abstract: A reflective target region is surrounded by a substantial light scattering region on a substrate to increase the contrast. The width of any reflective portion of the light scattering region is substantially smaller than the width of the target region along the orthogonal axis of the substrate. The light scattering region includes a plurality of peaks and valleys having parallel axis which are oblique to the axis of the substrate.

Abstract: A test device for setting motor-vehicle headlight beams is described, which essentially consists of a base plate (1) and the two open-up parts, namely the lens holder (2) and the test surface (3). The lens holder contains an aspheric lens (4) of which the optical axis (5) is parallel to the rest surface (6) of the base plate (1) and simultaneously perpendicular to the test surface when the device is in the opened-up, operational position. The lens is of such height and so corrected that the light of headlights mounted low, normally or high is passed without headlight elevation adjustment and is imaged on the test surface located approximately in the lens focus, and in that the test result is entirely independent of the particular headlight elevation.

Abstract: An invention is disclosed for optically determining the position of an object in space, using a single lens for triangulation, wherein an indexing light beam is projected to a lens on one side nonparallel to the optical axis of the lens. The lens focuses the indexing light beam at a known point on the other side of the lens at or near which reflection occurs by the object. Reflected light is captured by the lens and focused toward a photodetector which generates a signal indicating whether reflection occurred at the known point, thus indicating whether the object is present at the known point. If laser light is used, provision is made for, in effect, positioning the laser light source on the optical axis to reduce the effects of laser pointing instabilities. The invention can be used to measure the radii of rotating gas turbine engine rotors.

Abstract: In a length measuring device with a measuring transducer system, the curve of two sinusoidal test signals is dependent on the longitudinal movement of the measuring transducer system. An interpolation circuit delivers two high-resolution rectangular pulse sequences F1, F2 corresponding to the interpolated sinusoidal voltages and offset by 90.degree., to an evaluating circuit. To achieve a high-resolution at low speeds of travel and a low-resolution at high speeds, two rectangular pulse sequences S1, S2 or G1, G2, offset by 90.degree. and giving a low-resolution, are additionally derived at the interpolation circuit. A control logic circuit 19 monitors the test voltages for attainment of a certain value of the longitudinal movement per unit time or speed of travel.

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 co-ordinates relative to the sensor for all in-focus regions of the image. Refocusing the lens provides depth coverage.

Abstract: A device for indicating a definite direction, comprising a screen located in front and a screen located behind, which comprise opaque lines (3) separated by transparent interstices (4), whereby a moire pattern arises when the device is viewed. The screens (8,9) have different division. The opaque lines (3) have the same width in both screens (8,9).According to the invention the device is characterized in that one of the screens (9) is provided with only one opaque line less than the other of the screens (8), that in said one screen the width of a transparent interstice plus the width of an opaque line (3) is greater than or about equal to 1.5 times the width of the opaque line, but smaller than 1.9 times said width, preferably 1.5 times to 1.8 times the width of the opaque line. The two screens, further, are positioned symmetrically in relation to each other so that a central opaque line of one of the screens symmetrically overlaps a central transparent interstice of the other screen.

Abstract: Vehicle wheel alignment apparatus having preferred constructions in which the angle measuring components are assembled at each wheel in a unique cooperative arrangement and in which certain of the components represent existing wheel positions and other components relate the wheels in pairs so important alignment characteristics may be investigated for all wheels as well as the steerable wheels in relation to the non-steerable wheels.

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, by applying a beam of radiation to a region of the suspension, applying a field to the region and detecting a change, if any, in forward radiation scattering properties of the region due to the aligning of deflocculated particles, if any, of the suspension in the field.

Abstract: A non-intrusive method and apparatus for performing qualitative analysis of a liquid disposed within a container transparent to laser radiation comprises a first laser focused at a selected point within the liquid to produce or generate bubbles emanating from that location and a laser Doppler velocimeter which is intercepted by the rising bubbles to produce an output signal indicating both bubble size and velocity, as indication of liquid quality.

Abstract: At least one fiber optic light conductor extends from a source and detection area to a measurement area. In the measurement area, the fiber end is prepared with an end surface slanted relative to the fiber axis and the slanted surface is coated with a reflective material so that light conducted through the fiber is reflected from the end surface and through the side wall of the fiber onto an object being measured. Light is reflected from the object in an amount depending upon the position of the object and reflected light is carried through a similar path by the same or a similar optical fiber to the detector, such that the detector signal correlates to the position of the object.

Abstract: Examination of microstructures of LSI and VLSI devices is facilitated by employing a method in which the device is photographed through a darkfield illumination optical microscope and the resulting negative subjected to inverse processing to form a positive on a photographic film. The film is then developed to form photographic prints or transparencies which clearly illustrate the structure of the device. The entire structure of a device may be examined by alternately photographing the device and selectively etching layers of the device in order to expose underlying layers.

Abstract: A beam of light generated by a light source is separately applied to a measured film having unknown thickness and a reference film having a known thickness. The light transmitted through the measured film and the reference film are converted into electric signals which are electrically processed by a logarithmic operation circuit so as to produce a specific electric signal proportional to the difference between the thickness of the measured film and the reference film.