Abstract: An optical compensation type zoom optical system for microscopes comprising a first through fourth lens groups, and is so adapted as to displace said first and third lens groups for zooming while said second and fourth lens groups are kept fixed, said optical system being so designed as to assure little deviation of image planes during zooming operation and favorably correct various aberrations.

Abstract: A laser interference instrument for determination of the visual acuity of the human eye includes an interference optical system for producing an interference light pattern mounted on a slit lamp microscope disposed on an instrument support that is finely adjustable horizontally and in height. The interference optical system includes a laser light source and a rotatable turntable carrying a plurality of plane parallel plates or wedge plates which may be selectively moved into the light path of the laser light source to produce different interference patterns to be projected onto the human eye and which are then observable through the slit lamp microscope.

Abstract: An ophthalmic lens for providing correction of distortion of the vertical position of an image in a lens prescribed for the condition of anisometropia comprises upper and lower portions having different optical centers. The lens surfaces of the upper and lower portions merge in a transverse band providing a smooth transition between the upper and lower lens surfaces over a vertical distance for example of 2 - 8 mm. The transverse band removes the conventional sharply visible boundary between the upper and lower lens surfaces and by introducing aberration into the lens at this point deters effective use of the lens over an angle of vision corresponding substantially to the angle of a cone of light entering the pupil of the eye and so prevents double vision occurring at the boundary of the lens surfaces. Methods of production of the lens are also disclosed.

Abstract: A zoom lens comprising a front lens group, a plurality of movable lens groups and an image forming lens group, the front lens group having three sub-groups. The first sub-group counting from the front has a negative refractive power and is movable for focusing purposes. The intermediate or second sub-group has a positive refractive power and is movable for focusing to the front of the third sub-group which has a positive refractive power and which is stationary during focusing. The front lens group is characterized by fulfilling the following relationships: ##EQU1## WHEREIN F.sub.1 AND F.sub.

Abstract: A variable soft focus lens system particularly adapted for photography is provided. The soft focus lens system includes at least two lens groups defining a meniscus shaped air space there between. The relative width of the air space can be variable by movement of one of the lens groups relative to the other. This movement can introduce a controlled amount of spherical aberration to provide within certain parameters a soft focus image with an acceptable Petzval sum and flatness of the image plane. Various embodiments of the present invention within the inventive parameters can be utilized and include both stationary and variable soft focus lens system.

Abstract: A four component six lens element Gauss type objective having an aperture ratio of at least 1:2.4 and a field angle of greater than 40.degree. , comprising in the direction of light travel: a first single component positive meniscus concave toward the diaphragm; a second and third cemented doublet meniscus component concave toward the diaphragm, each of the doublet components having planar bond surfaces and a low positive or negative power of refraction; a diaphragm located between said second and third component; and a fourth single component having positive power of refraction with the weaker surface facing the diaphragm; wherein at least two pairs of spherical lens surfaces which are arranged symmetrically with respect to the diaphragm have identical radii of curvature; wherein the ratio of the dispersion values of the first and sixth lens, of the second and fifth lens, and of the third and fourth lens, respectively, in the direction of light travel, are essentially as follows:0.58 .ltoreq. .nu..sub.1 : .

Abstract: A mechanism for supporting an instrument which provides finger-tip adjustment in two or three directions is described. Torsional springs are used to counterbalance the instrument weight. An interconnected linkage arrangement permits vertical motion and horizontal motion in one direction. Horizontal motion in the other direction is obtained by axially sliding the instrument frame along shafts extending between pivot points of the interconnected linkage.An optional feature for ophthalmic instruments includes a mechanism for alternatively shifting the instrument in a horizontal direction between first and second chosen positions.

Abstract: An occluder for interrupting an energy beam is used to control the direction of travel and to stop a moveable member at a reference position from any position remote thereto.

Abstract: Disclosed is a cellulose ester contact lens having a medically acceptable warpage tolerance.

Abstract: Apparatus for the tachistoscopic projection of an image of projectable material. The apparatus includes a supporting structure and a light source. A lens mechanism is on the supporting structure optically aligned with the light source. The supporting structure is adapted to support the projectable material between the light source and the lens structure. The apparatus is designed for effecting relative displacement of the lens structure and the support holding the projectable material so as to bring the projected image into focus for a controlled viewing time and then out of focus while the material to be projected is retained stationary in projection position. A cam arrangement is employed which includes a cam surface and a cam follower. A manual actuator is on the lens structure to rotate the lens structure for relative movement between the cam follower and the cam surface and to bring the projected image into and out of focus.

Abstract: The invention introduces a coplanar rotational method of tracking the sun for use in a focusing solar collector that comprises of one or more linear focusing means such as cylindrical parabolic mirrors and linear lenses. Such a solar collector has one or more linear focal regions. It is particularly advantageous to use this tracking method in a large panel collector having multitude of linear focusing means. A plane parallel to the linear focal region or regions and perpendicular to the front plane of a solar collector is denoted as a focal plane. In applying the tracking method to the solar collector, the collector is rotated around an axis perpendicular to the front plane so that the sun'rays become parallel to the focal plane. The front plane remains substantially on the same plane during the tracking operation.

Abstract: This invention relates to spectacles' frame wherein its wearing position relative to the face of the user can be adjusted accurately by moving the nose pads vertically. When this frame is used for spectacles embodying multifocal lenses, including the portions for long distance viewing and the portions for near distance viewing, its wearing position can be changed upwardly so that the portions for near distance viewing are in alignment with the eyes of the user, thereby to afford the user longtime viewing with reduced fatigue. When the said frame is used for spectacles with monofocal lenses, its wearing position can be adjusted upwardly or downwardly so that the focal points of lenses are in correct alignment with the eyes of the user.

Abstract: An apparatus and process for determining subjective astigmatic and spherical prescription for the eye is disclosed. A target, consisting of a line of small angular divergence, is focused for maximum clarity by the adjustment of spherical optics, causing the line to become proximate to the retinal viewing plane of the eye. Change of astigmatic correction is made along at least one axis diagonal to the line target until maximum sharpness of the line results, without resultant spherical change and resultant movement of the image away from the retinal plane of the eye being tested. A second target, again consisting of a line of small angular divergence, is introduced; this line target is angularly inclined to the first target, preferably at 45.degree.. Spherical adjustment is made to obtain subjective line sharpness.

Abstract: A variable density polarizing attachment for spectacles having polarizing lenses therein is provided along with a method of making variable density polarizing spectacles. A pair of polarizing lenses are attached to standard spectacles or eyeglasses already having polarizing lenses therein utilizing posts attached to the lenses. The posts are grooved to rotatably hold a polarizing lens adjacent an existing polarizing lens on a pair of spectacles so that existing spectacles can be converted to variable density polarizing spectacles.

Abstract: The present invention relates to a macro zoom lens capable of taking a close up photograph at the one end at which a wide lens effect is obtained and at the other end at which a telephoto lens effect is obtained. One or two groups of the movable lenses in the zoom lens move in a movable direction along the optical axis at the one end at which a wide lens effect is obtained. At the other end, a telephoto lens effect is obtained. The distance between each lens and its next lens in the zoom lens in the ordinary zooming state is small as compared with the distance between the corresponding lenses at the time of taking a close up photograph.

Abstract: A magnifier having a relative aperture exeeding f/1, an angle of view wider than 2.degree. .times. 25.degree., and a pupil distance longer than 0.9 f, in particular for viewing the anode screen of an image intensifier tube forming part, for example, of a viewing device mounted on a vehicle.As viewed in the direction of the observer, the magnifier comprises, in succession,(a) a first component consisting of a positive lens;(b) a second component consisting of a positive power lens;(c) a third component consisting of a meniscus-shaped lens concave to the observer and comprising two lens components cemented together;(d) a fourth component consisting of a positive power lens; the sum of the powers of the two refractive surfaces of the second component having a value of between 0.15/f and 0.55/f, the power of the refractive surface of the third component facing the observer having a value of between 0.63/f and 1.03/f, and the sum of the powers of the two refractive surfaces of the fourth component ranging from 0.

Abstract: A tacheometer utilizes a gallium arsenide laser diode in a phase shifting distance encoder, a sinusoidal interpolator in a phase shifting shaft angle encoder, a mercury pool in a phase shifting two axis off-level encoder, a shared phase to digital decoder and a digital processor, to measure angles and distances corrected for off-level, speed of light variations, refraction and the earth's curvature. A reflecting telescope is coupled to the shaft angle encoder and is incorporated in both the phase shifting distance encoder and the alignment system. The reflecting telescope has a doublet objective lens with an embedded secondary reflective surface facing a primary mangin mirror. A biconcave element of the doublet objective lens also functions as a corrector for the secondary reflective surface. A compact objective lens system is thus realized, having minimal interference between the corrector for the secondary reflective surface and the optical path through the doublet objective lens.

Abstract: In an optical system having a mirror system for reflecting light from a field of interest to form a desired image on sensitive material disposed in a focal plane, the improvement characterized by the provision of a centrally located obscuration disposed adjacent the front of a mirror for intercepting light reflected from the sensitive material toward the mirror to prevent reflection from the mirror of said light reflected from the sensitive material from reilluminating the sensitive material, to thereby improve the contrast the desired image.

Abstract: An improved method is disclosed for determining the refractive correction for an eye. The method is an improvement over the method described by W. E. Humphrey in his U.S. Pat. No. 3,947,097. The improved method uses apparatus having only one variable astigmatic sub-system to achieve the same optical effects for which Humphrey specifically requires apparatus having two separate variable astigmatic sub-systems. The apparatus used is well-known in the art and includes variable spherical optics in combination with variable astigmatic optics, said variable astigmatic optics being equivalent to a rotatable, variable-power cross cylinder. Two stationary straight line targets, oriented in meridians substantially 45.degree. from one another are alternately focused by the patient. To focus each straight line target the patient adjusts separately both sphere power and cross cylinder.

Abstract: A removably mounted, slidably engagable, pivoting rear view mirror attachment for use on the temple portion of most conventional eye glasses.