Showing papers on "Lens (optics) published in 1969"

The significance of the shape of the lens and capsular energy changes in accommodation

Abstract: 1. A method for the estimation of the energy released by the anterior part of the lens capsule during accommodation is described. This includes (i) A determination of the pressure required to distend the capsule by a standard volume. (ii) The calculation from the photographed lens profiles of the degree of capsular contraction which occurs when the lens changes from the unaccommodated to the accommodated form. (iii) Capsular volume changes in vitro are then related to the surface area changes calculated for the lens in vivo. 2. A correlation exists between the stored capsular energy per unit area or surface tension and the accommodation power of different species. The human lens capsule releases 1170 ergs/cm2 while the more spherical lenses of the cat and rabbit release 520 and 485 ergs/cm2 respectively for a 10% change in lens diameter. The amount of energy which can be stored depends on the degree of flatness of the lens and the volume of the anterior segment. The flatter the lens and the smaller the volume of the anterior segment, the greater the capsular surface tension. 3. The anterior surface of the human lens remains ellipsoidal throughout life. The changes of accommodation which occur in presbyopia may therefore be related to the lens profiles at various ages. It is found that a coefficient obtained by dividing the anterior volume of the lens by the 5th power of the equatorial radius of the lens modifies the degree of accommodation for a given change of lens diameter. 4. The loss of accommodation is proportional to the effective capsular surface energy until about the age of 45. The effective capsular surface energy can be defined as the energy which gives the same change in lens dioptric power per erg regardless of the lenticular profile changes which occur with age. It is obtained by multiplying capsular surface tension at a given age by a ratio. This is obtained by dividing the profile coefficient mentioned in paragraph 3 of the given lens, by the profile coefficient of the reference lens aged 15 (0·068). The effective surface energy of the entire lens falls from 110 ergs at the age of 15 to 50 ergs at 60. Assuming that ciliary power remains unaltered 55% of the loss of accommodation is accounted for solely by the fall in Young's Modulus of elasticity of the capsule and the changing shape of the lens with age.

Ultraviolet Video-Viewing: The Television Camera as an Insect Eve

Abstract: A television camtiera, like the eyes of some insects, is sensitive to ultraviolet light. When equipped with an appropriate ultraviolet-transmitting lens, such a camera can be used for the direct examtiination of ultraviolet reflectiont patterns (for example, on flowers, butterflies) that are invisible to us, but visible to inisects.

Flexible fresnel refracting membrane adhered to ophthalmic lens

Abstract: A thin, fully conformable, plastic membrane which can be applied, and made to adhere with finger pressure, to spectacle lenses for quickly and impermanently changing one or more optical characteristics of the spectacle lenses. The membrane may be embossed on one of its surfaces to form a Fresnel-type lens or prism structure to introduce a deviation of the light ray, may be partially or entirely tinted to pass only certain wavelengths of light, may be diffused, or blurred uniformly or differentially, may have selective opaqued or transmitting areas or a combination thereof.

Range-Doppler Imaging with Motion through Resolution Cells

Abstract: Doppler processing in pulsed radar is analyzed for time intervals which involve motion through range resolution cells, the emphasis being on the range-Doppler imaging of a rigid rotating body. The objective of the theory is to derive a method for compensating for motion through range and cross-range resolution cells. The compensation ion procedure described is compatible with optical data processing. With such a two-dimensional processor, the method permits simultaneous eous compensation for all points in the target field. The s consists of taking the Fourier transform in the range dimension, followed by a gentle distortion of this range-transform plane, and that followed by a two-dimensional Fourier transform. Two implementations with experimental results are briefly mentioned. One implementation is all optical and utilizes a holographic hyperbolic lens and/or holographic conical lens. The other implementation, involves applying the appropriate te distortion electronically as th " range sweeps" from the pulse train are received and put on film.

Variable focus liquid lenses

Abstract: An ophthalmic lens has components respectively in the form of a meniscus and a thin resilient sheet, which are secured together so as to provide between them a cell filled with transparent liquid, the volume of liquid in the cell being variable to change the curvature of the sheet and thereby provide a continuous variation in the focus of the lens.

Remote radiation temperature sensor

Abstract: A SEMICONDUCTOR ELEMENT OF THE KING WHICH PRODUCES AN ELECTRICAL SIGNAL WHICH IS A FUNCTION OF THE INTENSITY OF INCIDENT INFRARED RADIATION IS DISPOSED AT ONE END OF A THIN TUBULAR BODY HAVING A TIP AT THE OPPOSITE END WHICH MAY BE DISPOSED IN A HIGH TEMPERATURE ENVIRONMENT. THE TIP HAS A CONICAL CONFIGURATION TO APPROXIMATE BLACKBODY CHARACTERISTICS AND EMITS THERMAL RADIATION TOWARDS THE DETECTOR THROUGH A SYSTEM OF COLLIMATORS AND LENSES WITHIN THE TUBE. IN ANOTHER EMBODIMENT, THE BODY OF THE DEVICE MAY BE A SOLID QUARTS OR SAPPHIRE ROD HAVING A CONICAL RADIATION OPAQUE TIP AT ONE END AND HAVING A CONCAVE OPPOSITE END TO DEFINE A FOCUSING LENS FOR DIRECTING INFRARED RADIATION ONTO THE DETECTOR ELEMENT.

Stereoscopic television system and apparatus

Abstract: A novel stereoscopic remote viewing system is provided including a remote camera unit having means for projecting a pair of binocular images of a remote object through a common lens system onto the sensitive face of a single television camera tube for transmission to a viewing unit having a television picture tube which may be viewed through a binocular image separation system that enables the viewer to see a stereoscopic image of the remote object. Means are provided in the remote camera unit for inverting one of the two images and then causing the two images to be projected mirror symmetrically onto the camera tube through the common lens system. Because of this image symmetry, distortion produced by the lens system or camera tube similarly affects both images. Means are provided in the image separation system of the viewing unit for transposing the transmitted inverted image and producing binocular separation of the images.

Three-dimensional display

Abstract: A varifocal mirror is typically comprised of a thin aluminized Mylar film that is stretched over a loudspeaker driven sinusoidally at low frequencies. When an object is placed a short distance from the film and the film is oscillated, the position of the image of the object in the mirror will be constantly swept back and forth in the image space with an amplitude typically several times the mirror displacement. In the system herein described a first varifocal mirror is used to sweep an image of a three-dimensional scene through the first of a pair of conjugate planes of a large aperture, low f-number lens. Inasmuch as such a lens has a small depth of focus, only one depth plane of the scene at a time will be in focus at the second of the pair of conjugate planes of the lens. Thus, as the varifocal mirror oscillates, the images of a series to two-dimensional depth planes are formed at the second conjugate plane. These twodimensional images are then viewed through a second varifocal mirror vibrating at the same frequency as the first mirror but 180* out of phase. Consequently, this mirror forms a series of two-dimensional virtual images each located in the correct depth plane so as to re-create the original three-dimensional scene. By recording the images formed at the second conjugate plane of the low f-number lens and then projecting them at the second varifocal mirror this system can be used for three-dimensional television or movies. By using a microscope to form the image that is swept through the first conjugate plane of the lens, this system can be used in three-dimensional microscopy. Alternatively, varifocal lenses can be used in place of the varifocal mirrors.

Effect of Microwaves on the Eye

Abstract: The utilization of microwave energy to produce an acute effect on the eyes of rabbits was experimentally investigated using both CW and pulsed power at 5.5 GHz. When present, lens opacities were developed within four days after exposures of sufficient intensity and duration; three minutes at the one-watt level were found to exceed cataractogenic threshold, while at the ?-watt level no acute effect was observed following a two-hour exposure.

Lens development. IV. Size, shape, and orientation.

Abstract: The right lenses were removed from a group of chick embryos at five days of incubation. Each lens was replaced by two lenses from donors of the same age. The donor lenses were implanted so that their equatorial planes lay at right angles to the equatorial plane of the host lens which they replaced. These cases were studied at 14 days of incubation. The volume of such lens pairs became regulated to correspond with that of a single 14-day-old lens. Each lens of an implanted pair assumed the shape of half of a normal 14 day lens bisected by a plane including its axis. Thus, the combined shape of a lens pair came to match that of a single 14 day lens. The lens pairs became internally reorganized: (1) lens epithelial cells which, at the time of implantation, had lain anterior to the plane defined by the edge of the eye cup continued to divide, and spread out to cover those exposed surfaces of the lens pair which lay toward the cornea; (2) those epithelial cells which were positioned toward the vitreous body enlarged and elongated to form lens fibers; (3) as a consequence of these events a new equatorial zone appeared which girdled the lens pair along the line of its contact with the cup margin; (4) in this fashion the orientation of the lens pair was readjusted in a manner appropriate for the host eye. These experiments demonstrate the existence of mechanisms which control the size, shape, and orientation of the developing lens. It is suggested that these mechanisms include an influence from the limbic mesenchyme which promotes cell elongation and cell packing, and a neural retinal influence which promotes enlargement of the lens cells as they form lens fibers. .his study deals with the mechanisms which control the size and shape of the embryonic lens, and which regulate its orientation in the growing eye. The size of the developing lens normally increases at a rate which is compatible with the dimensions of the developing eye. 1 ' 3 Harrison, 4 using early stages in amphibian development, demonstrated that this coordinated growth is brought about by a mutual adjustment of the growth rates of the lens and the eye wall. Our

Lens coating apparatus

Abstract: A lens coating apparatus consisting of a housing and means for producing a vacuum therein, said housing being divided into three chambers through which a lens-carrying holder may be passed in sequence, first a chamber in which the lenses ares preheated and a vacuum formed to drive off occluded gases therefrom, second a coating chamber in which the the lenses are coated by metallic vapors emanating from an incandescent source, and third a cooling chamber in which the lenses are gradually cooled, and a system of valves whereby lenses may be inserted in or removed from the preheating or cooling chambers, or advanced from one chamber to the next, without disturbing the vacuum in any other chamber.

Method of marking a transparent material

Abstract: An identification mark is made on a transparent workpiece, such as a lens for spectacles, by irradiating the material in a pattern desired for an identification mark with radiations which produce localized permanent stresses in the material that are visible by double refraction in polarized light. Suitable irradiation may be provided by corpuscular radiation, as by an electron beam, or electromagnetic radiation, as by laser beams. The radiation is preferably applied in an amount to produce the stresses within the material, not on the surface.

Camera with coordinated aperture and focus adjustment means

Abstract: A CAMERA HAVING BOTH FOCUSING AND LENS APERTURE ADJUSTMENTS IS PROVIDED WITH A COORDINATING MECHANISM FOR AUTOMATICALLY VARYING THE LENS FOCUS ADJUSTMENT AS A FUNCTION OF THE LENS APERTURE ADJUSTMENT, SO AS TO INSURE MAXIMUM DEPTH OF FIELD. IN A PREFERRED EMBODIMENT OF THE INVENTION, THIS MECHANISM IS INCORPORATED IN A CAMERA PROVIDED WITH AN AUTOMATIC RANGEFINDER LENS FOCUSING SYSTEM, SO THAT WHEN THE TRAVERSE OF THE RANGEFINDER FAILS TO DETECT SUBJECT AT A CLOSE DISTANCE, THE LENS IS THAN ADJUSTED TO ITS SHORTEST HYPERFOCAL SETTING COMPATIBLE WITH THE CONCURRENT ADJUSTMENT OF LENS APERTURE.

Contact lens washer with lens storage

Abstract: There is a container to hold lens washing fluid. A member is rotatably mounted in a lidlike member mounted on this container. This rotatably mounted member has a lower part that removably receives a perforated case for a contact lens. Mounted on the lidlike member is a turn knob that through gearing mounted in the lid turns the rotatable member carrying the lens case so that washing takes place of the contact lens carried in the perforated case. The container has spaced-apart depending legs between which a lens case carrier may be stored. The turn knob has two compartments with hinged tops for storage of right and left contact lenses.

Beam deflecting and focusing means for photoelectric monitoring, counting or control apparatus

Abstract: The beam deflecting and focusing system includes a lens member of approximately spherical shape formed of two transparent substantially hemispherical parts as well as a partly reflective partly transparent mirror located in the contact plane between the two hemispherical parts The mirror is arranged to reflect light from a light source to a reflector outside the lens members and to transmit reflected light from the reflector onto the photocell

Electrooptical control system for vehicles

Abstract: A laser or similar electromagnetic radiation with a lens system for converting the beam into a flat reference plane fanning outwardly from its source includes a vertical reference and control circuits drivingly connected to the lens system whereby the beam path can be maintained in the flat reference plane and at a preselected angle relative to true vertical as its supporting vehicle varies in attitude. The radiation source and lens system are mounted upon an earthmoving vehicle having an earthworking blade or similar tool which includes spaced apart optical sensors secured thereon which are connected to control circuits adjusting such blade or tool. These control circuits continuously adjust such blade or tool to a predetermined relationship relative to the flat reference plane of radiation, notwithstanding deflections or distortion in the machine frame. By mounting the radiation source and lens system along with its controls so that they are vertically adjustable on the vehicle, the height of the reference plane of radiation can be adjusted relative to an external reference thereby providing automatic control for a blade or tool in both slope and grade.

Means for cleaning contact lenses or the like

Abstract: A CONTACT LENS HOLDER HOLDS CONTACT LENSES SUSPENDED WITHIN A CLEANING SOLUTION BEING AGITATED BY A MOTOR DRIVEN AGITATOR WITHIN A CLEANING CONTAINER. THE LENS HOLDDER ALSO FITS INTERCHANGEABLY WITH A SOAKING CONTAINER. THE UNIT IS COMPACT, SIMPLE, LOW COST AND OF A CONSTRUCTION WHICH AVOIDS LIQUID LEAKAGE PROBLEMS.

Automatic headlight-washing system

Abstract: A vehicle headlight washer that is automatically actuated by a photocell actuator whenever the intensity of the light being passed through the headlight lens is reduced to a predetermined level by road grime and the like.

The design of three-element electrostatic electron lenses

Abstract: A procedure is described by which the focal properties of a three-element lens can be determined in terms of the properties of two-element lenses. Examples are given in some detail of the design of lenses to meet specific requirements and a graph is presented which can be used to design a lens of unit magnification which will work over a specified extreme voltage ratio in the range 6·25:1 to 170:1. The range of applicability of the method is discussed and a comparison made with measurements by Imhof and Read where only a limited agreement is expected. This comparison supports both the method and its limitations.

Lenses, Wave Optics, and Eikonal Functions*

Abstract: An approximate solution to the problem of a light wave propagating through a lens is obtained by systematically replacing the integrals required to solve the problem by their stationary-phase approximation. This approach is shown to yield (1) geometrical optics in its eikonal form, and (2) a diffraction theory of image formation applicable to lenses with large apertures and fields.

Device for controlling the amount of light rays in optical instruments

Abstract: The amount or intensity of light rays passing through a lens or transparent sheet, or reflected by a mirror is controlled by winding a film over the lens or mirror, the film having portions throughout its length having different degrees of opacity or different colors

Optical alignment method and apparatus

Abstract: Rays emanating from a point light source are incident, respectively, upon peripheral, intermediate, and paracentral zones of a lens chosen for a high degree of spherical aberration A small aperture stop, which may be the pupil of an observer''s eye, is placed substantially in the focal plane of said peripheral rays, thereby blocking out the intermediate rays and passing both the peripheral rays, which subsequently form an annular image, and the paracentral rays, which subsequently form an image of the point source Between the aberrating lens and the aperture stop, the rays are reflected from a specular surface which is known to have a perpendicular relationship to an optical axis sought to be aligned For example, the corneal surface of an ophthalmic patient''s eye might be the specular surface, where the optical axis of said eye is sought to be aligned to the optical axis of an analytical instrument By arranging the light source, the aberrating lens and the aperture stop in fixed relationship to an optical axis and maintaining the fixed unity of the source, lens, stop and axis while varying their position relative to that of the specular surface until the point image is brought to the center of the annular image, the two optical axes are aligned to one another

Intensity distribution of focussed laser beams in bio-medical studies

Abstract: Universal numerical solutions for the intensity of laser beams focussed by simple lenses having various amounts of primary spherical aberration have been obtained and are presented graphically in the form of lines of constant intensity (isophotes). The solutions demonstrate the increasingly non-uniform nature of the isophotes as the lens aberration function is increased. The existence of a multiplicity of intensity maxima, both along the optic axis and in off-axis positions, extending over comparatively large distances ( approximately mm) from the lens Gaussian focus, is disclosed. These must be taken into account in any quantitative assessment of the effects of laser beam radiation upon biological material.

Limitations in optical imaging devices at low light levels.

Abstract: An examination is made of the influence of objective lens parameters on the resolution capabilities of low light level imaging devices. From the resulting characteristics the dependence of the perception range of a given target on the incident light level is deduced. The restrictions imposed by larger lenses on the depth of field of acceptable focus are investigated, and comparisons made with the thresholds set by quantum-noise and optical resolution limitations. Degradations in the performance of image intensifiers due to different levels of image tube dark noise are also discussed.

Ultrasonic beam expander

Abstract: A single compact unit for generating and controlling an ultrasonic beam which includes an ultrasonic crystal generator and a solid ultrasonic lens with a liquid ultrasonic energy coupling therebetween which is contained in a housing joining the crystal and the lens. An antireflection coating on the ultrasonic lens surfaces improves transmission efficiency.

Optical tracking system utilizing a coaxial lens system

Abstract: The disclosure relates to an optical system suitable for acquiring and tracking a distant source of light. The optical system contains an acquisition lens system having a first field of view formed of a plurality of centrally apertured lenses which are coaxially positioned to directly receive light rays from a source and lens means coaxially positioned behind the apertured lenses. The image surface of the acquisition lens system is coaxially positioned behind the lens means. Further, a tracking lens system having a second field of view is coaxially positioned with respect to the acquisition lens system and comprises a centrally apertured elliptical primary mirror positioned to directly receive light rays from said source. The mirror aperture is larger than the outer surface of said centrally apertured lenses. A spherical secondary mirror is positioned to receive light rays from said primary mirror and reflect the rays through said acquisition lens system aperture and through the lens means. The tracking lens system image surface is coincidental with the acquisition lens system image surface. Moreover, filter means are mounted within said acquisition lens aperture for reflecting a portion of the light source rays transmitted by the tracking lens system. The filter means may be in the form of a beamsplitter which transmits the reflected rays through the acquisition lens system onto a second image surface remote from said first image surface.

The focal properties and aberrations of magnetic electron lenses

Abstract: A critical survey of the published data of the focal properties of magnetic electron lenses has revealed several inconsistencies between the findings of various authors. Some of these can be ascribed to errors in computation, but others stem from inherent limitations imposed by the conventional presentation of results in the form of `universal' curves or from the use of relative rather than fixed units, such as centimetres. The results of more accurate computations, especially of spherical aberration, are presented in a new form which is particularly suited to the determination of lenses of optimum performance. The results are applied to the question of determining the best possible objective lens for high resolution electron microscopy.