Abstract: An objective lens comprising a front positive meniscus element, a middle negative biconcave element and a rear positive biconvex element. Improved optical performance at a relative aperture of f/1.70 is achieved by the incorporation of an asphere on the rear surfaces of the first and second elements.

Abstract: A laser doppler anemometer includes a source producing a laser beam which is then split into a plurality of partial radiation beams. A common optical image-forming system illuminates a measuring volume by the partial radiation beams and receives the back-scattered signal radiation therefrom which is directed into a detector, and a partially reflecting mirror arrangement is positioned in the common optical imageforming system for the purpose of masking out scattered signal radiation leaving the common optical image-forming system. The partially reflecting mirror arrangement can comprise two mirrors disposed plane parallel to each other, and it can include light transmissive elliptical rings or strips. A pinhole diaphragm, adjustable in a direction orthogonal to the optical axis of the detector and through which the back-scattered signal radiation passes is also provided and precedes the detector.

Abstract: A telephoto lens system comprising a front lens group having a strong positive power and a rear lens group having a strong negative power and satisfying the following conditions, said telephoto lens system thus having a small telephoto ratio and aberrations corrected quite favorably.1. 0.32f < d.sub.6 < 0.40f2. 1.25f < r.sub.23. .vertline. 1/r.sub.6 .vertline.< 0.2/f4. 0.3 < - r.sub.3 /r.sub. 4 < 0.95. 0.9 < r.sub.1 /r.sub.5 < 1.16. 0.008f < d.sub.2 + d.sub.4 < 0.015f7. n.sub.1 , n.sub.3 < 1.55 , n.sub.2 > 1.78. .vertline..nu..sub.1 - .nu..sub.2 .vertline. > 35 , .vertline..nu..sub.3 - .nu..sub.2 .vertline.

Abstract: A lens for a small film format still camera which comprises four lens elements disposed behind the aperture defining means, and includes a double convex convergent lens element, a second double concave divergent lens element, a third double convex convergent element, and a fourth concave-plano lens element.

Abstract: In a zoom lens system dividable into a zooming lens component which varies the magnification without moving the image plane and a relay lens component, at least a part of the relay lens component is made to have no power so that the axial movement thereof may not vary the focal length of the zoom lens system and is moved along the optical axis in association with the zooming lens component to compensate the fluctuation of aberration caused by the movement of the zooming lens component.

Abstract: A lens meter for measuring the focal length of a sample lens with the sample lens disposed in a collimated light beam comprises a target, a first lens for forming an image of the target, light beam splitter means in the light beam on the image forming side of the first lens for splitting the light beam to form a second target image, a second lens having its focal points on the first and second target images through the light beam splitter means, target orthogonalizing means provided between the first and second lenses for making the first and second target images orthogonal to each other, a third lens for focusing the orthogonal target images collimated by the second lens, and target viewing means disposed at the focal point of the third lens.

Abstract: Particle analyzing method and apparatus are provided for measuring the intensity of light scattered from a particle as a function of angle. Particles such as biological cells are contained in a stream for travel along a path which includes a scatter line along which the particles pass successively. A beam of collimated monochromatic radiation is directed onto the flow path, and detector means are provided having a radiation acceptance geometry whose projection intercepts the beam along the scatter line. The projected acceptance geometry includes an aperture image located adjacent the scatter line and having a dimension in the direction of travel of the particles which is substantially less than the length of the scatter line such that the angle of scatter radiation detectable by the detector means varies according to the position of the particle along the scatter line. The output from the detector provides a measure of the scatter light intensity versus angle characteristic of the particle.

Abstract: An interferometric apparatus comprises an optical assembly which simultaneously directs two mutually coherent light pencils at different respective angles of incidence towards a point on a surface and receives the reflected light pencils therefrom. The assembly includes optical means bringing the reflected pencils at least partially into coincidence so that they can interfere optically in a manner varying with variation in the distance of points on the surface from a reference plane. The assembly may be combined with a microscope to form a "pupil-shearing micro-interferometer" for investigating surface topography.

Abstract: Light emitting elements such as light emitting diodes provided in the viewfinder of a camera are connected with a light measuring circuit including a photodetector through an A-D converter, a decoder and a gate circuit so that the light emitting elements may indicate exposure information in a digital form in accordance with the output of the light measuring circuit. An oscillator is connected with the A-D converter and the gate circuit for giving sampling pulses to the A-D converter and clock pulses to the gate circuit. Between the oscillator and the gate circuit is provided a duty modulator to change the duty cycle of the square wave transmitted from the oscillator to the gate circuit. The duty modulator is connected with the light measuring circuit or the A-D converter so as to control the duty cycle of the square wave in accordance with the output from the light measuring circuit.

Abstract: A wide angle photographic lens consisting of six lenses wherein the following conditions are satisfied;(1) .nu..sub.1, .nu..sub.2 > 50(2) F/1.3<.vertline.F.sub.1 . 2.vertline. < F/0.75, F.sub.1 . 2 < 0(3) 0.1 < .vertline.r.sub.5 /r.sub. 6 .vertline.< 1.

Abstract: The average aperture width in a small area of an apertured member, such as a shadow mask for a cathode-ray tube, is determined by passing a beam of substantially monochromatic light through an area of the member to form an interference pattern, detecting the intensities of at least two light fringes of the interference pattern, generating electrical signals which are representative of the detected intensities and then deriving the average width of apertures in the lit area of the member from the generated signals.

Abstract: An automatic digital indicating lens meter is provided with an optical system having a light beam source and a target which reciprocally moves within a certain range along the optical axis, the target having several circular luminous points. An image pickup system including a lens to be inspected, such as a mono-focal point spherical lens or a bi-focal non-spherical point lens, is fixed on the optical axis approximately mating with the luminous centers of a light beam source collimator and a light beam receiving collimator. A photo electric converter is located at the focal plane of the receiving collimator; on an extension of said optical axis. An electric circuit analyses by scanning lines, the images detected by said electric light converter as time series signals and counts the position when the time band width of the brightness signal becomes minimum in the course of movement of the target.

Abstract: An improved integrating nephelometer having superior sensitivity and long-term stability to previous designs includes a container defining a measurement chamber. A continuously energized light source, such as a tungsten filament incandescent bulb, illuminates the measurement chamber through an opal glass diffuser. The intensity of the light source is regulated in one embodiment by a simple optical-electric feedback system, and in another embodiment by a voltage regulated supply. A cone of observation of the chamber is defined by a plurality of spaced, apertured plates located in the chamber, at right angles to the light source. A measuring photomultiplier tube views the cone of observation and provides an output signal including components resulting from detected photoelectrons, noise, and thermally emitted "dark current" electrons. A photon-detecting apparatus removes the noise component and provides an output pulse for each photoelectron and "dark current" electron.

Abstract: Processes for the accurate, rapid and inexpensive testing and inspecting of oncave and convex lens surfaces through holographic means requiring no beamsplitters, mirrors or overpower optics, and wherein a hologram formed in accordance with one aspect of the invention contains the entire interferometer and serves as both a master and illuminating source for both concave and said convex surfaces to be so tested.

Abstract: A non-linear lens possesses distortion characteristics which are such that objects along the optical axis of the lens occupy disproportionately large areas of the image cast by the lens, whereas objects near the periphery of the field of view occupy a disproportionately small area of the image. The distortion characteristics approximate the formula H=sin.sup.1/3 .theta. where H is height measured from the optical axis and .theta. is the angle measured from the optical axis. The image cast by the lens falls on the vidicon of a television camera where it is scanned and transmitted to a projector. Since the lens enlarges objects in the vicinity of the optical axis, those objects are transmitted with much greater detail than objects in the peripheral region of the view. The transmitted image is reproduced at a projector and the reproduced image is rectified through another lens having identical distortion characteristics. This lens casts the rectified image on a spherical screen.

Abstract: A long exposure photometer-digitizer operative in an integration mode to receive weak illumination as from celestial observations through a telescope or from field or laboratory observations of objects and to provide a recorded digital representation thereof. A silicon, vidicon illumination sensor is employed to provide a wide dynamic range, sensitive and linear response over a large spectral region. Cumulative photon interaction with the vidicon tube during a long exposure is achieved by operating the vidicon at a reduced temperature which minimizes dark current effects and promotes integration mode operation. After a predetermined vidicon exposure interval the image electrically stored in the target is read out by a scanning electron beam, digitized and recorded to provide an immediately available digital record of the object. The target is sensitized before each exposure.

Abstract: Apparatus and method for detecting the refractive index and rate of fluid flowing through an elongated flow cell, having applications in liquid chromatography. The cell may be of circular cross section and has an input window in one end, an exit window in the other, and a longitudinal side wall. A light source directs divergent light through the entrance window, longitudinally through the cell, to pass through the exit window and be sensed by a photoelectric detector outside the exit window. In a first embodiment, heat transmission apparatus connected to the cell establishes a constant temperature gradient in the cell. This temperature gradient, preferably, has a component perpendicular to the longitudinal dimension of the cell and extending toward the center of the cell. This causes the density of the fluid in the cell to vary as an increasing function of its distance from the walls. The index of refraction of the fluid thus, in this embodiment, increases with distance from the cell walls.

Abstract: An objective lens comprising three elements, a front positive biconvex element, a middle negative biconcave element and a rear positive biconvex element. The first two elements are made of inexpensive plastic materials. Aberration correction at a high relative aperture is improved by the use of aspheres on selected surfaces of the first and second elements.

Abstract: A pancratic wide-angle objective comprises a stationary negative front component in the form of a single meniscus with a convex forward surface, an axially movable intermediate component consisting of a biconvex lens, and a stationary multilens positive rear component separated from the front component by an airspace greater than the focal length of the latter. The individual focal lengths of the front, intermediate and rear components have absolute values in a ratio of approximately 4:5:3.

Abstract: A varifocal objective has an axially shiftable positive front component, an axially shiftable negative intermediate component, and a fixed positive rear component or basic lens group. The latter component consists of five closely spaced lens members, all but the second of them singlets and all but the third of them positively refracting. The intermediate component is separated from the rear component by a diaphragm space which in a position of close approach of these components, corresponding to maximum focal length, is still substantially greater than any air space between the lens members of the rear component. With a varifocal ratio close to 3:1, the distance between the front and rear components is the same in the positions of maximum and minimum focal lengths.