Abstract: An electro-optical device mounted over a conveyed stream of articles for sensing the passage of each article by projecting a single spot of light onto the articles and measuring the reflectance of that spot from two different angles. The measured reflectance values are fed to an electronic comparator which produces an output signal when one reflectance value exceeds the other by a predetermined amount.

Abstract: A method and apparatus are disclosed for controlling plasma etching processes in which a thin layer is etched away to expose a substrate. Coherent light is directed onto the surface being etched, so that the change in reflectivity of the surface upon exposure of the underlying substrate produces a detectable change in the characteristics of the light reflected. A derivative detector having a variable timer is provided to sample continuously the reflected light and provide a control signal in response to a predetermined change in the characteristics of the light reflected, which is used to terminate the plasma etch process before an overetch condition occurs. The method and apparatus of the invention will detect a desired end point of etching through insulation to an underlying metal substrate, through metal to an underlying insulation substrate, through one insulation type to an underlying substrate of another insulation type and through one metal to an underlying substrate of another metal.

Abstract: A meter and method for measuring the intensity of reflected or other light. The meter is particularly suitable for use by blind or visually impared diabetics to determine sugar level in their urine and in one embodiment is a handheld, battery-powered, audio-output device. A chemical impregnated sample under test is illuminated with a light source and reflected light is detected to form an electrical measurement signal. In order to minimize variations in light source output, the measurement signal is typically formed as a ratio of logrithmically scaled signals derived from the sample under test and from the light source. The measurement signal is compared with reference levels and the comparison results are encoded to provide signals to an audio or other indicator. A time sequencer is provided for causing the measurement signal to be examined at a predetermined time.

Abstract: A system for checking copy quality variables within the image area of an electrophotographic machine. During a test cycle, quality is checked by producing sample test areas within the photoconductor image area ordinarily used for producing copies. Reflectance measurements are made on the sample test areas and compared to a dynamically floating reference achieved by a reflectance measurement from a cleaned portion of the photoconductor within the image area. The testing circuit is balanced so that the same reflectance voltage should be generated whether the single reflectivity-sensing device is viewing a sample test area or a cleaned reference area. The system checks for quality variables such as toner concentration, image voltage and an abnormally low reflectance photoconductor and provides a partial check on its own fault-free condition during periods when it is not in use.

Abstract: Apparatus and method for pinning the value of a white, gray or otherwise colored, single-shaded vector in an electrophotographic machine. The vector is the value of the image voltage minus the developer voltage. Valuation of changes in the image voltage are obtained by (1) sensing the reflectivity of a developed single-shaded image and converting that into a representative voltage; (2) sensing the reflectivity of the bare photoconductor and converting that into a representative voltage; (3) obtaining a comparison of the representative image and reference voltages; and (4) noting changes in the comparison. Pinning the vector calls for adjusting the member for producing the vector such as the developer voltage or document illumination intensity level an amount necessary to compensate for the change in image voltage.

Abstract: A system for checking copy quality variables within the image area of an electrophotographic machine. During a test cycle, quality is checked by producing sample test areas within the photoconductor image area ordinarily used for producing copies. Reflectance measurements are made on the sample test areas and compared to a dynamically floating reference achieved by a reflectance measurement from a cleaned portion within the image area of the photoconductor. The testing circuit is balanced so that the same reflectance voltage should be generated whether the single reflectivity-sensing device is viewing a sample test area or a cleaned reference area. The system checks for quality variables such as toner concentration, image voltage, and an abnormally low reflectance photoconductor and provides a partial check on its own fault-free condition during periods when it is not in use.

Abstract: Apparatus for measuring reflected or transmitted light is described. The apparatus comprises filter type spectrophotometer having a wavelength range of from about 200 nm (nanometers) to about 1,100 nm which includes a sample illuminating light source capable of producing an extremely intense light of short duration; light diffusing means; a light filter for transmission of a selected wave-length; at least two independent light sensing means; and separate means defining light transmission paths for the passage of light from the light source to one light sensing means and from the illuminated sample to the other light sensing means.In a preferred embodiment the apparatus includes a light diffusing integrating sphere. In another embodiment, a replaceable or repositionable module can be used to convert the apparatus from reflectance to transmittance spectrophotomer.

Abstract: The specification discloses an optical web inspection system for detecting imperfections in a web having a longitudinal axis and moving in a plane across an inspection area. Radiation means is disposed above the plane of the web and transverse to the longitudinal axis of the web for directing radiant energy on the web at the inspection area. A plurality of sensors are mounted transverse to the longitudinal axis of the web and above the inspection area for receiving reflected radiation from successive transverse portions of the web passing across the inspection area. The plurality of sensors generate electrical output signals representing the intensity of the reflected radiation from the successive transverse portions of the web. Circuitry for periodically summing the electrical output signals from selected ones of the sensors is provided to generate a summation signal representative of the sum of reflected radiation from selected discrete segments of a plurality of the transverse portions of the web.

Abstract: A method of analyzing a liquid sample by applying the sample to a composite test paper composed of a strip plastic transparent film and a reflectivity reference or compensation paper piece and a plurality of color reaction test paper pieces affixed to the strip, feeding the test paper to a spectral reflectivity measuring device a predetermined period of time after the application, and calculating the corrected reflectivities of each of the paper pieces from the measured amounts of reflected light at varying wavelengths to determine the concentration of the abnormal substance contained in the test sample, free of measuring errors due to the color if any of the sample, differences in the color developed and variations in the thickness of the color reaction test paper pieces and reflectivity reference or compensation paper piece. A system for practicing this method is also disclosed.

Abstract: A field instrument for measuring the chemical composition of a solid core sample includes means for forming a smooth surface along the core sample, a light source for illuminating the smoothed surface, a photocell for sensing monochromatic light reflected from the surface of the core sample, means for providing relative movement between the core sample and the photocell, and means for converting the photocell output into a measurement of the amount of a chemical component being analyzed contained in the core sample. To avoid wide variations in measured chemical content, caused by non-uniform distribution of the material being analyzed within the core sample, reflected light is integrated over a selected area of the core sample.

Abstract: A secondary detection system for utilization with a security validation apparatus wherein a sensing is made of the amount of light reflected from a given area of a paper security. Fundamentally, the invention consists of an infrared lamp or other emission source casting light through a tunnel and upon a highly reflective but partially transmissive surface. The reflective surface directs a large portion of the light onto the paper security. A first solar cell is provided in juxtaposition to the reflective surface for sensing the amount of light reflected onto the paper while a second solar cell is provided for receiving and sensing that quantity of light reflected back from the paper. A comparator circuit is interconnected between the two solar cells to determine the validity of the paper security on the basis of the percentage of light incident to the paper which is reflected therefrom.

Abstract: An on-line detector for peach pits and peach pit fragments and the like remaining in peach halves following a pitting operation includes a sealed housing bordered on one side by an inclined view plate disposed between a feeding belt and a take-away belt. A peach half, pit cavity down, is passed by a viewing line above the view plate. Two different wavelengths of light are directed toward the viewing line and are reflected by a passing fruit section toward an array of light sensors. One of the wavelengths of light is controlled in on-off condition by a clock, being turned on during only a portion of each clock cycle. Output from each one in the array of light sensors is sampled during the portion of each clock cycle that the one wavelength is on, and differenced with the light sensor output from that sensor when the other wavelength only is on. Differencing occurs during each clock cycle and a difference output appears only in the presence of a pit or a pit fragment.

Abstract: A collimated beam of light is directed onto a face of a microcircuit chip. If the configuration side of the chip is up and if the chip has a typical pattern predominantly comprised of two orthogonal sets of lines, the light reflected from the chip will be formed in a cross shaped diffraction pattern with most of the light concentrated in the center of the cross. If, however, the chip is upside down so that a plain face is exposed to the light, the light will be reflected fairly uniformly from the chip. By measuring the reflected light in a small center zone as well as in a larger zone and the light measurements are compared, it can be determined whether the diffraction pattern is present thereby revealing whether the chip is right side up, i.e. configuration side up.

Abstract: A color recognition system is used to distinguish between objects of various colors. A plurality of light sources are arranged at a sensing station to reflect light from the object as it passes the sensing station to a plurality of cooperatively mounted light detectors. The signals produced by the plurality of detectors are compared with a reference voltage and the comparison utilized to differentiate between objects of different colors passing the sensing station. In a particular embodiment of the invention, the color recognition system is incorporated in a ball separator for a pool table to separate the entirely white cue ball from the partially or wholly differently colored object balls and to divert the cue ball into a first storage station and the object balls into a separate storage station.

Abstract: Apparatus for indicating the concentration of a particular constituent in a fluid including a sensing device for sensing the concentration of a particular constituent in a fluid and for providing a response; and an electronic device including a differentiating circuit for differentiating an electrical input signal which is proportional to the sensing response for providing a substantially constant output signal which is a measure of the sensing response differentiated with respect to time, which output signal is an indication of the concentration of the constituent in the fluid. The sensing device is operated during a sampling period in which the reaction of such constituent to the sensing device is linear.

Abstract: The purpose of this invention is to reveal the surface properties, such as smoothness and resulting printability of a rapidly moving strip of material, such as paper. To accomplish this, the production process is continuously monitored, without error due to environmental conditions such as dust and dirt on optical surfaces, temperature affects, lamp degradation, etc. An index of printability relative to smoothness is obtained by integrating the plateau areas in the optical field of view. A unique combination of approach angle, selected wave length of infra red radiation, horizontal polarization of search beam, and use of four optical paths to obtain mathematical model equivalency, is employed.