Abstract: The measurement of the scattering properties of very small particles by electro-optical means generally requires the use of an intense, though highly spatially inhomogeneous, light source such as a laser. Many instruments require, therefore, that the intersection of the particle stream with the illumination source be precisely regulated so that the flux incident on the particle be known accurately. A method and apparatus are described by which means the absolute intensity of the light incident on the particle need not be known. A special structure and measurement process are described by which means small particles are differentiated from larger particles grazing the illumination beam.

Abstract: An optical refractometer for automatically determining the principal indices of a specimen receives an incident radiation beam which is reflected by a first rotatable mirror onto a reflecting surface of a first elliptical mirror wherein the axis of rotation of the first rotatable surface extends through a first focus of the first elliptical mirror. A hemicylinder has a center of curvature at a second focus of the first elliptical mirror and rotatably and translatably mounts a specimen about a first axis and along second and third axes, respectively, such that a portion of the specimen is located at the second focus to receive the reflected incident beam from the first rotatable surface. A second elliptical mirror has third and fourth foci and a second surface for reflecting the incident radiation beam from the second elliptical mirror with an axis of rotation extending through the fourth focus with the third focus being at the first axis coincident with the second focus for producing a reflected beam output.

Abstract: In a semiconductor color sensor circuit with two photodiodes having mutually different wavelength sensitivity characteristics, the ratio of numbers or areas of two types of transistors for logarithmic compression of signals from these photodiodes is adjusted so that errors in output voltage due to changes in temperature can be reduced and the dynamic range of illuminance of incident light can be enlarged.

Abstract: Optical measurement apparatus includes a cell (12) adapted to receive fluid for testing and a light source (16) arranged to direct an incident light beam (5) into the cell. A hollow intergration sphere (14) and light-sensitive detector (26) are provided to detect at least a pre-determined portion of light emitted by a segment (13) of the cell transversely of the direction of said incident light beam.The light source (16) and the cell (12) are arranged so that the light incident on the cell is not collimated but, as it traverses segment of the cell, is confined to the cell by total internal reflection, unless otherwise scattered by particles in the cell.

Abstract: There is disclosed a particle analyzing apparatus having an irradiating optical system for irradiating a particle to be examined, flowing in a flow section of a flow cell, with a light beam, a measuring optical system for measuring the light scattered by the particle, an optical detection system for projecting a positioning light beam onto a determined wall of the flow cell and detecting the light reflected from the wall, and a device for varying the relative position of the measuring optical system with respect to the flow cell according to the output of the optical detection system.

Abstract: An apparatus for measuring the relative positions of hole patterns is disclosed wherein two or more fiber optic bundles disposed within first and second holes and connected to one or more sources of light and light sensitive, position sensing devices provide two, three, four, or five axis measurements of the relative positions of the two holes. By measuring the position of the light from the source transmitted via an optical bundle in the first hole and received by an optical bundle in the second hole, a precise measurement system that senses mismatch and the direction thereof with a very high degree of accuracy is achieved. The movement of plane surfaces may also be measured with the present apparatus by attaching either the transmitting or receiving side of the apparatus to a part which is subjected to a load, and measuring the resulting change in the position of the light beam illuminating the light sensitive, position sensing device.

Abstract: A densitometric head for measuring ink density of prints in a running printing machine includes a light source for transmitting light on the measured surfaces and sensors for receiving the remitted light. To simplify the construction and eliminate heat effects of the light source, the latter is arranged in one focal point of an elliptic reflector whereas the measured surfaces are situated in or close to the other focal point where an image light source is formed from the light reflected in the reflector. A heat protective filter is arranged between the two focal points to eliminate heat effects on the sensor.

Abstract: An optical apparatus for the detection of scattered light has a light source for supplying a beam of light with a determined wavelength, an objective lens for focusing the light beam on a test object and a photo receptor for receiving the light scattered around the objective lens by the boundaries of a pattern on the test object. The apparatus further has a light converging ring member and a filter arranged in the optical path between the test object and the photo receptor to allow the scattered light from the test object to enter the filter and the photo receptor after the scattered light is converted into a beam of substantially collimated rays by the action of reflection and convergence by the converging ring member.

Abstract: A support (56) is suitable for holding a substrate (10) horizontal, said substrate having a drop of liquid placed thereon. A source of light (74) associated with a collimator (78) forms a primary beam of parallel light which is directed perpendicularly (86) to the substrate. A receiver surface (126, 128) having a known geometry and placed in a known position relative to the substrate intercepts a secondary beam (124) produced by interaction between the primary beam and the drop and the substrate. The value of the contact angle between the drop and the substrate may be deduced from the illuminated zone on said receiver surface.

Abstract: A radial or azmuthal non-resonant flow-through optoacoustic cell is operated without windows, completely eliminating the window background interference. The cell is constructed of an elongated tube the length of which is 34.times.10.sup.3 cm.times.1/f, where f is the light source modulating frequency and is made of conducting material which is perforated along the center one-half length with holes. A metalized sheath surrounds this center region to form a capacitor microphone.

Abstract: The extinction coefficient of atmospheric aerosol is measured by an instrument in which a single light beam from a graybody source is alternately directed through two similar optical paths to a detector. Each optical path traverses an equal length region of ambient air. Aerosols are filtered from the ambient air region of one optical path .The detector measures the modulation of the incident radiation and its output is a function of the extinction coefficient of the ambient air under test. A second detector is used to monitor the beam power. Processing electronics compute the extinction coefficient of the ambient air under test from the detector outputs. The ambient air regions of the two beam paths are alternately filtered for improved performance.

Abstract: An instrument for measuring opacity of oil mist for lubrication purposes is set forth. In the preferred and illustrated embodiment, the apparatus is preferably installed in a pipe cross, opposing legs of the cross conduct oil mist past the opposite two legs supporting an opacity measuring system. Utilizing a bridge voltage supply to power an amplifier forming a reference voltage for reference diodes, a first photo cell is provided with a reference light from LED created light directed to the reference. A second LED directs light through the oil mist. The quantity of light is measured by a second photo cell reflecting the light absorbence of the sample, and the output of the two measuring devices is determined in a differential amplifier, driving a meter movement. The direct current signal is at a safe current range for use of the transmitter in a hazardous environment and is inversely proportional to the percent transmission of the signal.

Abstract: A bore measuring system to optically measure the diameter of hole on thin boards, such as printed circuit boards. The bore measuring system of the invention is so contrived as to irradiate a hole to be measured, to project the light through the hole onto the receiving surface of the image sensor and to indicate the diameter of the hole by converting the output from the image sensor, corresponding to the size of the image, into a numerical figure. Unlike the conventional methods, measurement is possible simply by irradiating the hole to be measured without inserting any pin or measuring rod of a hole gauge into the hole, and without projecting the image to be measured onto a screen. Accordingly, the operation is quite simple and the measuring time can be shortened, yet measuring errors can be avoided. Moreover, the automatic display of hole diameter in a numerical value eliminates the reading errors which often occur with conventional methods.

Abstract: A water film surface is irradiated with light from a detecting unit's light source. Light reflected from the water film surface is converted into an electrical signal by a sensor (photoelectric converting means) in the unit. The converted electrical signal is supplied to a processing unit through a cable. The processing unit calculates the water film thickness based on the electrical signal. The calculated thickness is displayed on a display in the detecting unit.

Abstract: A method for measuring the formation of optical density at 350 to 700 nm in a material is disclosed. The method comprises directing through a solution of the material with light-scattering means suspended therein a beam of light having a wavelength in the range of 350 to 700 nm at which the material absorbs light, and measuring the scattered intensity of the light leaving the solution at a given angle.

Abstract: A method is disclosed for measuring the rate and/or extent of movement of oscillatory element positioned on an oscillating system by passing a reference beam towards a reference detector over a reference edge. The reference edge is fixed relative to the element. The measurement beam is directed towards the measurement detector over a measurement edge of a surface adapted to move together with the element relative to the reference edge. The movement of the measurement edge cuts the measurement beam as it moves into the path of the measurement beam. The rate and/or extent of movement of the element relative to the reference edge is determined by comparing the illumination received by each of the detectors. Apparatus is also disclosed for measuring the rate and/or extent of movement of an oscillatory element positioned on an oscillating system including a measurement edge adapted to move together with the element. A reference edge is maintained stationary relative to the measurement edge.

Abstract: A soft contact lens measuring device. A cylindrical lens support defines a cavity and pedestal for immersing a soft contact lens in a saline solution. A piston engages the support and can be operated by the user to force air in controlled amounts through a narrow passageway extending up through the pedestal to the saline solution. A bubble forms and rises until it is trapped by the lens. The interface between the bubble and the lens makes a convenient surface for focusing a radiuscope to allow lens dimensions to be determined.

Abstract: An apparatus for measuring an optical axis direction in which an intensity of the light transmissive to a specimen to be measured disposed between two polarizers is measured by an orthogonal Nicol optical system which uniaxially comprises a light source, said two polarizers, and a light receptor thereby determining the optical axis direction of the specimen to be measured. The apparatus comprises a conveyor for continuously moving the specimen in an elongated form in the direction intersecting with the orthogonal Nicol optical system at a right angle. An intensity of the transmissive light is measured during the period of time when the specimen is fed from one side of a casing, and removed from the other side of the casing. The casing encases the optical system.

Abstract: The disclosure depicts a measuring instrument incorporating in relatively movable portions thereof optical type displacement detecting devices. Each of the optical type displacement detecting devices includes: a main scale having fringes constituted by reflecting portions and non-reflecting portions, both of which are lined up alternately; an index scale having fringes constituted by light transmitting portions and non-light transmitting portions, both of which are lined up alternately; a light emitting element for irradiating an index scale and a main scale; and a light receiving element for receiving light reflected by the main scale through the index scale to emit an electric signal corresponding to a relative displacement value between the both scales. The main scale is provided thereon with a disturbance preventing layer which absorbs light transmitted through the non-reflecting portions of the main scale not to allow the light to be reflected to the index scale.

Abstract: An optoelectric comparison apparatus for structures on plane surfaces or for planar structures has a laser light source 35 the operational light beam of which is split into two component beams 21, 22 by an optical displacement device 26, 25 for laterally displacing part of a beam. These two component light beams 21, 22 impinge on the mirror surfaces of a mirror wheel 11 obliquely to the axis of rotation 20. Two mutually crossed flat first strip mirrors 12, 13 are arranged in the direction of the light reflected from the mirror wheel 11 and each receive only one of the emergent component light beams 14, 15. The emergent component light beams 14, 15 are deflected in substantially opposite directions where, in each case, a further plane second strip mirror 16, 17 is provided which reflects the light to the scanning surface parallel to the light beams 14, 15 which enter into the first strip mirrors 12, 13.