Showing papers on "Lens (optics) published in 1978"

Lens design fundamentals

Abstract: * Thoroughly revised and expanded to reflect the substantial changes in the field since its publication in 1978* Strong emphasis on how to effectively use software design packages, indispensable to today's lens designer* Many new lens design problems and examples - ranging from simple lenses to complex zoom lenses and mirror systems - give insight for both the newcomer and specialist in the field Rudolf Kingslake is regarded as the American father of lens design; his book, not revised since its publication in 1978, is viewed as a classic in the field. Naturally, the area has developed considerably since the book was published, the most obvious changes being the availability of powerful lens design software packages, theoretical advances, and new surface fabrication technologies. This book provides the skills and knowledge to move into the exciting world of contemporary lens design and develop practical lenses needed for the great variety of 21st-century applications. Continuing to focus on fundamental methods and procedures of lens design, this revision by R. Barry Johnson of a classic modernizes symbology and nomenclature, improves conceptual clarity, broadens the study of aberrations, enhances discussion of multi-mirror systems, adds tilted and decentered systems with eccentric pupils, explores use of aberrations in the optimization process, enlarges field flattener concepts, expands discussion of image analysis, includes many new exemplary examples to illustrate concepts, and much more. Optical engineers working in lens design will find this book an invaluable guide to lens design in traditional and emerging areas of application; it is also suited to advanced undergraduate or graduate course in lens design principles and as a self-learning tutorial and reference for the practitioner. Rudolf Kingslake (1903-2003) was a founding faculty member of the Institute of Optics at The University of Rochester (1929) and remained teaching until 1983. Concurrently, in 1937 he became head of the lens design department at Eastman Kodak until his retirement in 1969. Dr. Kingslake published numerous papers, books, and was awarded many patents. He was a Fellow of SPIE and OSA, and an OSA President (1947-48). He was awarded the Progress Medal from SMPTE (1978), the Frederic Ives Medal (1973), and the Gold Medal of SPIE (1980). R. Barry Johnson has been involved for over 40 years in lens design, optical systems design, and electro-optical systems engineering. He has been a faculty member at three academic institutions engaged in optics education and research, co-founder of the Center for Applied Optics at the University of Alabama in Huntsville, employed by a number of companies, and provided consulting services. Dr. Johnson is an SPIE Fellow and Life Member, OSA Fellow, and an SPIE President (1987). He published numerous papers and has been awarded many patents. Dr. Johnson was founder and Chairman of the SPIE Lens Design Working Group (1988-2002), is an active Program Committee member of the International Optical Design Conference, and perennial co-chair of the annual SPIE Current Developments in Lens Design and Optical Engineering Conference. * Thoroughly revised and expanded to reflect the substantial changes in the field since its publication in 1978* Strong emphasis on how to effectively use software design packages, indispensable to today's lens designer* Many new lens design problems and examples - ranging from simple lenses to complex zoom lenses and mirror systems - give insight for both the newcomer and specialist in the field

Multifocal ophthalmic lens

Abstract: The specification discloses a multifocal ophthalmic lens to provide a variable focusing power lens for near and farsighted corrected vision. The lens includes a first and second lens element. First and second electrodes are disposed between the lens elements, and a film of liquid crystal is disposed between the electrodes. A voltage supply source is provided for applying a voltage to the electrodes to vary the index presented by the liquid crystal film to thereby provide a variation in the index of refraction and focal length of the lens elements. Circuitry is provided for varying the voltage applied to the electrodes to determine the focusing power of the lens.

Ring pattern of a lens-axicon doublet illuminated by a Gaussian beam

Abstract: An axicon and a lens are combined to form an optical system producing a ring-shaped pattern. The purpose of this paper is to show that when a lens-axicon combination is illuminated by a Gaussian beam, the transverse distribution of the focal ring is also a Gaussian distribution. The typical width of this distribution was found to be, in the case of the lens-axicon combination, 1.65 times greater than the typical width of the Gaussian beam obtained by focusing the same beam using the lens alone. This focusing system is well suited for the drilling of good quality large diameter holes using a high power laser beam.

Color separation gratings.

Abstract: Special phase gratings are described by means of which the red, green, and blue color components of colored objects are generated side by side around the optical axis in the image plane of a lens. An analysis of these color separation gratings is given, and theoretical and experimental results for some grating samples are presented.

Method of making high quality plastic lenses

Abstract: A method of making plastic lenses by casting a liquid monomer and a photosensitive catalyst between two transparent optical molds One of the transparent molds having a convex lens on the outer surface to focus ultraviolet light toward the center of the monomer activating the photosensitive catalyst and initiating polymerization in the center of the plastic lens material Polymerizing the monomer to form a solid lens having optical surfaces formed by the transparent molds

Characteristic material signatures by acoustic microscopy

Abstract: Image contrast in the scanning acoustic microscope is affected by axial translation of the object along the lens axis. The explanation lies in the recognition that the acoustic reflection coefficient varies with axial translation in a manner that is unique and characteristic of the material involved. Examples of material signatures are given and used to explain the observed image contrast. The instrument's ability to obtain crystallographic information is suggested.

Photoacoustics on a microscopic scale

Abstract: We have modified a transmission acoustic microscope by replacing the input lens with an optical counterpart. The input to this system comes from a mode‐locked and Q‐switched Nd : YAG laser at 1.06 μm. Acoustic signals arising from thermoelastic coupling are generated in metallic films at frequencies determined by the modulation envelope of the optical beam. The output acoustic lens and transducer responsive to sound waves at 840 MHz detect the acoustic energy which comes from the heated volume (∼2‐μm diameter) near the focal region. The sample is mechanically scanned through the focal point in a raster pattern to record the photoacoustic images. We suggest this as a method for collecting new information on microscopic structures.

Packaged fiber optic modules

Abstract: A module for a fiber optic data transmission system which will accommodate either a suitable light source or a photoelectric detector. The module incorporates an integrated electronic assembly, such as a hybrid microelectronic assembly. The assembly has provision for a photoelectric transducer which preferably has a cylindrical mount disposed in a cylindrical recess of the electronic assembly. The entire assembly may be surrounded by a cylindrical can having a transparent window. The transducer is provided with a collimating lens which permits it to receive or emit a collimated light beam. Between the fiber optic bundle and the transducer, there is preferably disposed a focusing lens. The focusing lens receives or emits the collimated light beam and focuses it on the fiber optic bundle. A housing surrounds the entire module. Means, such as a retainer ring, are provided for holding the electronic assembly within the housing. Similar means are provided for maintaining the focusing lens within the housing. The distance between the focusing lens and the optical bundle is established by means of a ferrule which in turn is urged toward the housing by a nut and threaded sleeve portion.

Contact lens with a hydrophilic, polyelectrolyte complex coating and method for forming same

Abstract: Soft and hard contact lenses with an ionic charge on their surface are treated with a lens solution containing an oppositely charged ionic polymer to form a hydrophilic polyelectrolyte complex on the lens surface, which complex acts as a hydrogel and improves the properties of the lens.

Method for surface treatment of contact lenses

Abstract: Surface treatment for hard or dehydrated hydrophilic contact lenses, to reduce the deposit of impurities thereon, comprising subjecting the lens, after shaping and polishing, to a gas discharge, e.g., in an oxygen atmosphere.

Recording and playback system

Abstract: Apparatus and process for writing upon a video record and for reading the video information from the video record after the writing is complete, and the video disc structure so written. The apparatus includes a laser and an optical system which directs the laser beam to a prepared rotating disc. The disc has a very thin metallic coating. A first lens acts to diverge the laser beam so as to fill a miscroscope objective lens which focuses the beam to a small spot of approximately 1 μm in diameter. The spot contains sufficient energy to melt the metallic surface coating on the disc. The surface tension of the molten metal makes it draw back leaving a hole. Video information in the form suitable for display with a T.V. monitor is applied to an F.M. modulator for forming an F.M. signal. The F.M. signal intensity modulates a laser beam passing through a Pockels cell--Glan prism combination. The series of holes forming the coating of the disc represent the F.M. signal. Since an F.M. signal characteristically is a frequency variable signal, the length of the holes and the distance between successive holes vary to represent the F.M. signal.

Optical fibre terminations and connectors

Abstract: A termination for an optical fibre is formed with an integral lens for producing an expanded parallel light beam. A pair of terminations provide an optical coupler for connecting between a corresponding pair of optical fibres.

Liquid crystal image projector system

Abstract: There is disclosed a liquid crystal image projector which is suitable for use as an image source in an aircraft head-up display system. In this application, the projector provides extremely bright and high contrast symbology for the aircraft pilot. More generally, the projector has application wherever a television-type raster and/or calligraphic symbology display is needed. The increase in brightness and contrast ratio is achieved by using a reflector to concentrate light from a light source onto the liquid crystal display cell from whence it is reflected through an optical aperture stop in the reflector to the projecting lens and thence to a viewing surface.

Paper secured against forgery and device for checking the authenticity of such papers

Abstract: The paper carries, at one or more points, materials which, in the excited condition, fluoresce in the visible, ultraviolet, or infra-red spectral range in the characteristic emission spectra. The device includes a light source for exciting fluorescent substances, a condenser lens concentrating the light emitted by the paper, a narrow band interference filter, a focusing lens, and a series of photocells arranged in the focal plane of the focusing lens. The geometric arrangement of the photocells is chosen appropriately to identify an emission-line doublet. The outputs of the photocells are fed to a pre-amplifier and then to a comparator which may effect a subtraction of the amplified photocell output to provide an output signal. In a variation, the quotient of the photocurrents of two photocells is compared to establish the authenticity of the paper.

Hydrogel contact lens

Abstract: A soft contact lens provided with a front surface whose cross section describes the curve whose equation, in polar coordinates, is ρ=R+kR(1-cos θ)/(1+cos θ) where R is the radius of curvature of a spherical lens of power equal at least approximately to the most hyperopic (or least myopic) power meridian of the ametropia plus about one-half of any presbyopic addition required by the patient, and k is a constant of eccentricity which may vary with the hydrophilic properties of the lens material and is determined for each material such that the visual acuity for distance and near vision is 20/20 or better with the aforesaid R value. The value of k lies within the range 0.005 to 0.1.

Method and apparatus for providing dynamic focussing and beam steering in an ultrasonic apparatus

Abstract: An acoustic lens having nonuniform cross sectional thickness is disposed in the path of an ultrasonic energy search beam traveling from a transducer probe to an object to be examined. In an alternative embodiment the lens has at least one contoured surface. As the lens undergoes motion in a plane substantially normal to the direction of the search beam, the search beam exhibits a varying focal zone depth and beam path for providing real time ultrasonic scanning of the examined object.

Gaussian-beam theory of lenses with annular aperture

Abstract: The light distribution produced by a lens with an annular aperture with approximately Gaussian cross-section is calculated by summing over Laguerre-Gaussian modes. The advantage of this approach is that it gives the intensity at all points in space. This is of particular value when the cross-section of the annulus is narrow compared with its radius, because then the intensity varies slowly along the optic axis. Intensity is plotted for the region near the focus, far from the focus, along the optic axis, and on the geometrical cone of illumination. Contours of equal intensity in the focal region are also plotted. The possibility of constructing low-loss resonators with annular mirrors is also discussed.

Light device, lens, and fiber optic package

Abstract: In a packaging means for packaging together a light source or detecting means, a lens, and an optical fiber there is provided a sleeve for holding the light source/detector at one end of the sleeve and the lens at the other end to form a lens package. To hold the lens package there is provided a housing having first and second cavities opening onto each other and separated by shoulder means. The optical fiber is positioned in the first cavity with its end just short of the shoulder means. The lens package is retained in the second cavity with the lens abutted against said shoulder means with its focal axis aligned with the axis of the optical fiber and further with the tolerance error of the distance between said lens and the end of the optical fiber being determined largely by the variations in radius of said lens and variations in the position of the end of the optical fiber. The lens package can be retained in the second cavity by a matrix of flexible plastic partitions extending into the second cavity from the shoulder means in a box-like configuration which frictionally grips the lens package in an aligned position with the optical fiber.

Laser beam level instrument

Abstract: A lightweight, portable laser beam level instrument has an optical path which includes a solid state light source; a pendulous, positive lens; a rotatable pentaprism or mirror equivalent; and a glass plate which is tilted to provide fine tuning. The level instrument also includes a damping mechanism, a waterproof enclosure and a clip-in battery pack. The solid state light source is a diode in a specific embodiment and produces an intense beam of rapidly diverging infrared laser light. The postiive lens is suspended below the diode at approximately the focal length of the lens from the diode to collimate the light. The pendulous suspension lens maintains the beam in a truly vertical position with respect to the earth to provide self-leveling in a limited range of movement of the instrument. The pentaprism or equivalent converts this vertical beam to a horizontal beam. The glass plate is positioned between the diode and the lens and can be tilted in two orthogonal degrees of adjustment to provide a fine tuning for optical centering of the diode and the lens. Oscillation of the pendulous lens is damped by magnetic or air damping.

Process for the production of contact lenses

Abstract: There is provided a mold comprising a male and a female mold member fabricated from thermoplastic polymeric materials which, in very thin sections are flexible under polymerization conditions, but, under said conditions are sufficiently inflexible in thick sections to retain their shape and surface characteristics. Said mold is provided, on either the male or the female member with a thin rim which, during the polymerization process, flexes and permits the mold members to approach each other and compensate for the shrinkage that occurs during polymerization. Said thin rim further forms the edge of the finished lens.

Propagation of the generalized radiance through lenses

Abstract: We prove that in a large and significant class of cases the generalized radiance is, except for transmission losses, invariant along light rays traversing a lens.

The state of water in normal and senile cataractous lenses studied by nuclear magnetic resonance

Abstract: Normal and senile cataractous lenses were studied by nuclear magnetic resonance in order to get information about the state of water during the progression of cataract. Water proton spin-spin (T2) and spin-lattice relaxation times—in the laboratory and the rotating frame—() were measured at 34 and 90 MHz. At temperatures below −9°C the relaxation times of protons in “non-freezable” component of lens water were measured as a function of the temperature, and T1 and T2 relaxation times were found to be the same for both the normal and the cataractous lenses. At temperatures above −9°C a marked difference in relaxation times T1 and T2 was found between normal and completely opaque lenses. It was concluded that the most characteristic difference between the normal and completely opaque lenses should be accounted for by the change in the “bound”-to-“free” ratio of lens water.

Artificial and solar lighting system

Abstract: A sunlight collector, containing a Fresnel lens, is mounted on the roof of a building and tracks the sun during daylight hours. A concentrated beam of sunlight is directed through a light transmission channel to locations within the building where the light is distributed. The transmission channel utilizes a focusing lens for further concentrating the solar beam, refocusing lenses for correcting divergences in the beam, reflectors for redirecting the beam, and beam splitters for distributing the beam into light fixtures located throughout the interior of the building. The light fixtures contain filters for controlling the intensity and spectral content of the incoming beam, and optical elements for dispersing the beam. Additionally, the fixture contains rigidly mounted fluorescent tubes, providing artificial light, which are automatically energized when the solar light is insufficient for lighting purposes. A diffusing element is used for uniformly radiating both the artificial and the dispersed solar light from the fixture into the building interior.

Micro lens array and micro deflector assembly for fly's eye electron beam tubes using silicon components and techniques of fabrication and assembly

Abstract: A combined fine focusing micro lens array and micro deflector assembly for use in electron beam tubes of the fly's eye type is provided. The assembly comprises a fine focusing micro lens array sub-assembly formed from a plurality of spaced-apart stacked parallel thin planar apertured silicon semiconductor lens plates each having an array of micro lens aperture openings. The lens plates each have highly conductive surfaces and are secured to glass rods for holding the plates in stacked parallel spaced-apart relationship with the apertures axially aligned in parallel. A micro deflector assembly is adjacent to the micro lens array sub-assembly. A micro deflector element axially aligned with each respective fine focusing lens element serves for deflecting an electron beam passing through along orthogonal x-y directional axes of movement normal to the electron beam path. The deflector elements are comprised by two orthogonally arrayed sets of parallel spaced-apart deflector bars with alternate bars of each set of deflector bars being interconnected electrically for common connection to a respective source of fine x-y deflection potential. The thin planar apertured silicon lens plates comprising the micro lens array are held together in stacked parallel assembled relationship by spaced-apart glass support rods whose longitudinal axes extend at right angles to the plates and to which the planar silicon lens plates are secured at their periphery. The two orthogonally arrayed sets of parallel spaced-apart deflection bars forming the sets of micro-deflector elements likewise preferably comprise parallel plates or bars of polycrystalline silicon having a highly conductive metalized surface. The micro deflector bars likewise are held in assembled spaced-apart parallel relationship by respective sets of spaced-apart parallel supporting glass rods whose longitudinal axes extend in a plane parallel to the plane of the deflector bars but at right angles thereto and to which the ends of the deflector bars are thermally bonded. The fine focusing micro lens array and micro deflector sub-assembly thus comprised, are secured together in assembled relation by additional glass support rods being disposed about the outer peripheries of the micro lens and micro deflector sub-assemblies and being secured thereto by thermal bonding such as by fusion.

Arrangement for locating radiaring sources

Abstract: A sensor system for determining the spatial location of radiation relative to the sensor including three unit sensors each having a cylindrical optical lens and a linear array of photosensitive elements positioned in the focal plane at a fixed angle with respect to the longitudinal axis of the lens. Each lens determines substantially a plane of radiation passing through the source. The unit sensors are arranged to define three separate planes having the radiation source being detected as common point. The detected signals are processed to identify respectively the serial position of the elements activated by the focused radiation. Ancillary calculating means calculates the location of the source from the serial position information. By detecting a plurality of sources coupled to a movable body, the present invention enables the user to continuously determine the direction of a fixed axis of the movable body.

Electrostatic einzel lenses with reduced spherical aberration for use in field‐emission guns

Abstract: Focusing properties and aberration coefficients are calculated for electrostatic einzel lenses suitable for use as preaccelerator lenses in field‐emission electron guns. Various lens shapes are analyzed, and asymmetric designs with conical central electrodes are found to have reduced spherical aberration. A lens shape with optimized geometry is found to have a spherical aberration coefficient of less than six times the working distance from the lens to the focal point. This lens has a bored conical central electrode located close to a thin first electrode. Calculations indicate that a field‐emission gun using such a lens should be able to provide a 0.24 μA beam from a 1100 A effective source size into an emission half‐angle of 2.4×10−2 rad. At lower emission angles the source size would be limited by chromatic rather than spherical aberration.

Electromagnetic field in the focal region of wide-angular annular lens and mirror systems

Abstract: The time-averaged electric energy density near the focus of a lens or mirror system with annular aperture is calculated. The distribution shows greater difference from the paraxial approximation than for the full circular aperture. The vector distribution of the polarisation after focusing greatly affects the field near the focus. In particular, a mirror with annular aperture which deflects a plane-polarised wave through a small angle gives a distribution in the focal plane which exhibits bright rings around a dark centre. The field distribution of an annular system is found to consist of just two modes of free space.

Optical signal communicating apparatus

Abstract: A noncontacting data-transmission system for transmitting data between rotating and nonrotating members includes at least one light source capable of transmitting modulated light signals disposed in one of the members. At least one light detector arranged along the same optical axis as the source and along an axis coincident with the axis of rotation of the rotating members is located in the other of the members. A lens having an optical center lying on an axis coincident with the axis of rotation of the rotating member is interposed between the light source and detector. The detector is located at the conjugate of the light source, such that an image of the light source is formed by the lens at the detector. The central portion of the lens may be modified, such as by forming a central opening in the lens, such that only an annular portion of the lens is utilized to form the image of the light source on the detector. In an embodiment of the invention disclosed, a plurality of data-transmitting light sources and detectors are coaxially arranged at conjugate positions in the members undergoing relative rotation.