Abstract: A zoom lens system comprising, from front to rear, a focusing lens group having a positive refractive power, a front movable lens group, a middle movable lens group, a rear movable lens group and a relay lens group, the front and middle lens groups having negative refractive powers. When zooming, these three movable lens groups are moved simultaneously and independently of each other in such a manner that the front and middle groups at the telephoto side occupy nearer positions to the image plane than those which they occupy at the wide-angle side. The axial separation between the front and middle groups at the telephoto side is smaller than that at the wide-angle side. Further, the front and rear surfaces of the middle movable lens group are convex toward the image side.

Abstract: A histogram of the volume of the particles in a sample of fluid-suspended particles, including those in the submicron region, can be obtained by using an incident light beam having a wavelength approximately twice the average particle diameter in each of the ranges of particle sizes making up the histogram. The 90.degree. scatter from the sample is measured in two orthogonal polarizations. The first polarization has its electric vector perpendicular to the plane containing the point of observation and the incident light beam and the second is parallel to that plane. The magnitude of the light flux having the second polarization is subtracted from that having the first polarization in each range to give a measure of the volume of the particles in that range.

Abstract: A rotary motion sensor which employs an endless, closed-loop, multiple turn fiber interferometer. Coherent laser radiation is coupled into the fiber interferometer in both a clockwise and counter-clockwise direction and is permitted to traverse the entire interferometer waveguide many times so as to increase the cumulative phase shift due to multiple traversal. Means are provided for coupling the coherent radiation into and out of the fiber interferometer. Means are also provided for generating a pair of reference optical signals which are heterodyned with the extracted clockwise and couterclockwise signals to produce a pair of beat frequency signals at manageable, acoustic frequencies. The relative cumulative phase shift between the output acoustic signals and the circulating signals are the same so as to provide an extremely precise measurement of the rate of rotation.

Abstract: A zoom optical system is composed of a positive focusing lens group, a negative variating lens group, a negative compensating lens group and a positive rear fixed lens group. A rotating grooved cam moves the variating lens group and the compensating lens group in a given relation to each other along the optical axis in the normal focusing range. The focusing lens group is moved along the optical axis normal range for focusing. The variating lens group is kept stationary on the optical axis while the compensating lens group is moved along the optical axis during close-range focusing.

Abstract: The disclosed invention relates to methods and apparatus for obtaining the dimension, position or angle of an object using a point on the object boundary surface to create a diffraction wave when illuminated by a laser beam or other source of electro-magnetic radiation. This diffraction wave is then analyzed to obtain information as to the position point tangent to the laser beam or the angular orientation of the object boundary at said object point.

Abstract: A medium magnification objective for video disks comprising a first, second, third and fourth lens components in which the first lens component is a negative lens, the second lens component is a positive meniscus lens with its concave surface positioned toward the object, the third lens component consists of one or two positive lenses, the fourth lens component is a negative meniscus lens with its convex surface positioned toward the object, and for which the number of lenses constituting the objective is small, the working distance is large, flatness of image is high and resolving power is also high.

Abstract: An objective system including a prime lens objective followed by a negative attachment which consists of a negative doublet of a biconvex lens cemented together with a biconcave lens, a biconvex lens, a middle biconcave lens followed after an axial air space by a biconvex lens and a biconcave lens. The middle biconcave lens has a front surface smaller in radius of curvature than that of a rear surface thereof. The present invention is to provide for an increased axial separation between the front principal point of the attachment and the focal point of the prime lens objective while improving field curvature of image.

Abstract: A smoke detector and housing assembly therefore in which the housing components are designed to allow rapid assembly of the detector with a minimum amount of labor. In a preferred embodiment of the invention a retainer for a photo-cell and light source is provided with a medial portion retaining the photo-cell and portions extending forwardly from the ends of the medial portion for projecting a light beam through the field of view of the photo-cell. The retainer is molded in two similar halves and fastened together after assembly of the photo-cell, light source, and other components therein.A base plate is provided with suitable apertures for receiving the forwardly projecting portions of the retainer so that after assembly they protrude from the forward face thereof. A cylindrical member and cover are mounted on the forward face of the base plate between the forwardly projecting portions of the retainer, forming a dark chamber across which the light beam projects, and into which the photo-cell views.

Abstract: A catadioptric objective lens system that has a field of view of 10.degree., and that will provide: a large relative aperture of 1.28; optimum performance in the S-20 spectral range; and, maximum light throughout the region of apertures for exactly the 10.degree. field of view.

Abstract: A method of detecting a small elemental spectral source in a larger, spectral background, including producing a first interferogram of each element of an object area including the source and background; producing a second complementary interferogram of each element of that object area; projecting onto a detector images of the first and second interferograms and defocussing one of the first and second interferograms for providing a fluctuating elemental interferogram output from each element of the detector which receives an interferogram derived from the element of the object area that contains a source which spectrally distinguishes from the background, while reducing the output corresponding to each element containing no source to a constant and non-fluctuating level.

Abstract: The specific disclosure provides a soft contact lens comprising an eye contacting inner surface, and an annular carrier portion including an outer surface spaced from the eye contacting inner surface not greater than a predetermined distance. An optical portion is encompassed by the carrier portion and includes an outer surface with all points thereon spaced from the inner surface a distance greater than the predetermined distance. An intermediate portion interconnects the carrier and optical portions and includes an outer surface extending downwardly and outwardly from the outer surface of the optical portion to the outer surface of the carrier portion.

Abstract: A telephoto lens system having improved focusing capabilities is provided wherein a first lens group of an overall positive refractive power is mounted on the object side of a second lens group of an overall negative refractive power. The lens components of the second lens group are capable of providing a simplified focusing mode of operation. The second lens group can comprise a first negative lens component and an image side second positive lens component. The second positive lens component is movably mounted for focusing the entire lens system on relatively close objects as its translates toward the object side. The first lens group is spaced a distance from the second lens group having an absolute value greater than 0.15f wherein f is the focal length of the entire lens system. Additionally, the composite absolute values of the focal lengths of the front lens group and the negative lens component of the second lens group is greater than 1.2f.

Abstract: An apparatus for analyzing the size distribution and quantity of small particles in an aerosol comprises at least one smooth filter bearing a reflecting coating and means for measuring the change in reflectance due to the deposition of intercepted particles. At least one additional filter contains linear pores extending substantially normal to the filter surface and has a negligible transmission outside the pores. Also realized are means for measuring the change in transmission due to the retention of particles in and around the pores.

Abstract: Apparatus for measuring the refractive powers of a lens and displaying the measured powers in so-called prescription form. A focimeter is equipped with means for generating electrical signals indicative of the net refractive powers of the lens, which signals are extended to novel electronic logic and control means for ultimately reading out and/or displaying the lens powers in a prescription form having "sphere" and "cylinder" components of power. Selectively activable control means determine whether the prescription is displayed in so-called "+ cylinder" notation or "- cylinder" notation. Additional means are provided for indicating which of two possible axis angles is correctly associated with the particular displayed component of cylinder power.

Abstract: A zoom objective with a varifocal ratio close to 2:1, particularly for a projector, has a stationary positive front component, a single axially shiftable negative lens and a stationary multilens rear component. An object-side positive lens member of the rear component, adjoining the shiftable negative lens, has a focal length smaller than that of the group constituted by the remaining, image-side lens members of this component. The negatively refracting third member of the rear component may be a doublet with a positively refracting cemented surface, convex toward the image side, or an equivalent lens pair separated by a small air gap.

Abstract: The sheared interference fringe of a wavefront from an object under test is obtained by recording on a first hologram the interference fringe formed between a first reference light beam and two light beams having slightly different angles of incidence with respect to the first hologram, recording on a second hologram the interference fringe formed between a second reference light beam and the two light beams reconstructed by an illuminating light beam incident on the first hologram from the same direction as the first reference light beam, placing the first and second holograms thus obtained at a prescribed distance from each other, causing a light beam from the object under test to impinge upon the first hologram from the same direction as the first reference light beam to produce light beams and projecting the produced light beams upon the second hologram for thereby causing the second hologram to produce light beams in the same direction as the second reference light beam.

Abstract: A wide angle lens system of the retrofocus type having a ratio of back focal length to equivalent focal length of greater than two and a large relative aperture. The lens system comprises 13 elements in nine groups including four consecutive doublets and is capable of focusing to an object distance of eleven equivalent focal lengths from the front vertex thereof.

Abstract: A variant Ernostar type long focus lens system having a very short overall length comprising a first positive miniscus lens, a second positive meniscus lens and a third positive meniscus lens which are arranged very close to one another, a fourth negative meniscus lens and a fifth positive meniscus lens, and said lens system having a focal length of 180-200 mm and a telephoto ratio of approximately 0.93.

Abstract: A method for measuring a roughness profile of a surface optically is provided. The method essentially comprises projecting through a converging optical system a pair of light rays on a surface to be measured, the light rays being focused slightly before and behind the measuring surface, receiving reflections of the projected light rays by photoelectric means to produce two different electric signals representing the intensity of the reflections of the two light rays, detecting a roughness profile of the surface on the basis of the difference of the two electric signals, and moving the light rays along the measuring surface to obtain a continuous roughness profile of the surface.

Abstract: A telephoto lens system consists of a first convergent group and a divergent group disposed rearwardly of the first group for forming a substantially afocal converter, and a second convergent group disposed rearwardly of said divergent group. The first convergent lens group and the divergent lens group are movable relative to each other along the optical axis of the lens system for effecting focusing.