Abstract: An optical distortion analyzer system which is capable of automatically quantifying with a high degree of accuracy and repeatability the optical quality of transparencies such as windshields or windows. The analyzer system is made up of a platform adapted to support the transparency with two degrees of freedom. A probe beam of electromagnetic radiation emanating from, for example, a laser is passed through the transparency as the transparency is moved about a horizontal and vertical axis establishing a plurality of test points on the transparency. An analyzer unit receives the probe beam and therefrom establishes horizontal and vertical deviations in the transparency as well as determining the cylindrical and spherical lens power components and principal meridan angle of the transparency. A processor provides recognizable opthalmic parameters of the above characteristics of the transparency and correlates these parameters with the plurality of test points on the transparency.

Abstract: A test lens and a photo-detector array are fixed in position along an optical axis a fixed distance from each other. Light is reflected by the front and rear surfaces of the test lens through an objective lens and is detected by the photo-detector array. The detected light is processed to produce a pixel count by video processing electronics. Control electronics adjusts the focusing of the objective lens by incremental displacement along the optical axis during a measurement cycle and significant focus position data is obtained from the video processing electronics to determine best focus location from which test lens data is derived.

Abstract: An apparatus for measuring the optical characteristics of an optical system includes a light source, a collimator lens, a mask, a detector, and a circuit for measuring information received from the detector. The light source projects a beam of light through the collimator lens and then through the optical system. The beam of light then passes through the mask, which has a pattern of at least two non-parallel, straight lines on it, and is projected onto the detector. With the information provided to the circuit by the detector the optical characteristics of the optical system are determined. The circuit determines the optical characteristics of the optical system by evaluating changes in the length and gradient angles of the lines projected onto the detector from the mask.

Abstract: A hand-held lens meter including first and second optical systems mounted in a substantially Y-shaped hand-holdable body is disclosed. The first optical system includes a target, a lens rest and an objective lens. The target is slidably mounted in a grip portion of the lens meter body while the two optical systems are mounted in the upper legs thereof. The second optical system includes a relay lens, a focusing screen, an eyepiece lens and first and second reflecting surfaces which may be consituted either by first and second mirrors or a pentagonal prism. A prism is provided preferably as the reflecting surface of the first optical system with the prism having an optical path length longer than the outside diameter of the objective lens. The target is slidably moved along the optical axis in response to rotation of a power-measuring dial which is calibrated in terms of the powers of lenses to be measured.

Abstract: Measurement of the refractive power of a contact lens comprises joining a contact lens to be measured with the surface of a reference lens system of small refractive power whose optical elements are known, and then measuring the back focal distance of the combined optical system to thereby determine the refractive power of the contact lens to be measured.

Abstract: The invention contemplates a method and apparatus for automatically performing digital measurement of vertex dioptric powers in the principal planes of toric spectacle lenses. A spectacle lens is transilluminated by a parallel-ray bundle of monochromatic light which, after passage through the spectacle lens, is limited by an annular stop in the immediate vicinity of the vertex of the spectacle lens. A beamsplitter divides the light which passes through the spectacle lens into two individual light beams. As a result, an elliptical figure is projected to two planes, in each of which is located at least one self-scanning diode line.

Abstract: An automatic lens meter for measuring a pherical power, a cylinder power, an angle of cylinder axis, and a power of prism of an ophthalmic lens. The automatic lens meter is characterized by the use of a shading device to obtain the coordinates of the points at which respective light rays emitted from respective pin-holes of a multiple-pin-hole disc cross the second focal plane of an objective lens, according to a shading time lag among respective light rays.

Abstract: Apparatus is disclosed for determining, with improved accuracy, the back vertex power of a hydrated soft contact lens. The increased accuracy is determined by sequentially using several optical modes to provide additional information needed to accurately calculate back vertex power. Lens thickness, sagittal height and posterior radius values are also accurately obtained with the apparatus.Optionally, a mode for determining lens radius and thickness is also disclosed.

Abstract: Lens testing apparatus and method by which the focus of a lens can be set to sharply image a distant object in a select focal or reference plane. The apparatus comprises a conventional television camera on which a lens can be mounted in a predetermined manner to focus light from a collimated light beam onto the photosensitive surface of the television camera tube. As the lens is adjusted, the area of the pattern of illumination formed by the lens on the photosensitive surface changes in accordance with the state of focus of the lens. The television camera scans the illuminated area and produces a video signal which is received by electronic circuitry that is operative to indicate the size of the area of the pattern of illumination as the lens state of focus is changed. The smallest area indicated corresponds to the best focus adjustment for the lens. Lens focal length also can be determined with the apparatus by making appropriate measurements when the smallest area is indicated.

Abstract: Improved apparatus for transporting and positioning a contact lens immersed in a liquid for inspection is disclosed. The device has a plurality of supporting surfaces and a weight to biase the lens against the surfaces during immersion and prevent unintentional motion of the lens in the liquid during inspection.

Abstract: An automatic lensmeter (48) for determining the refractive properties of a test lens (76) including optics (52, 58, 62, 64, 68, 70, 72, 74) for producing a collimated, nonrotational beam of light, equally disposed about and propagating along an optical axis (50), which is refracted by the test lens (76), a nonrotational mask (18) having an annulus (24) for generating a stationary elliptical loop (28) of light at a detecting plane (26), the loop (28) having a shape, size and location dependent on the refractive properties of the test lens (76), and a photodetector (31) at the plane (26) to intercept the loop 28. The lensmeter (48) has no moving optical components and, due to the loop 28, provides an infinite number of points to determine very accurately one or more of the refractive properties, thereby overcoming problems with prior automatic lensmeters having relatively rotational optics and/or providing a finite number of points at a detecting plane.

Abstract: An apparatus and method for measuring the dioptric power, resolving power, and astigmatic power of small lenses, and particularly for testing the acceptability of surgically implantable intraocular lenses. The apparatus is comprised of an optical system which images a reticle at its focus. The optical system includes a light source which is condensed on a test reticle which in turn is focused on a reference surface from which the measurements are made. A lens to be tested is positioned with its posterior surface coincident with the plane on which the reticle is focused. A conjugate viewing system is provided at 90.degree. to the imaging system for viewing the image of the reticle focused on this plane. Adjusting means are provided for positioning the reticle image to coincide with the second focal plane of the lens being tested. The reticle image in this plane is converted to a colored image to distinguish it from the first focused image at the reference surface.

Abstract: An improved lensmeter comprising a conventional optical system and a novel displaying system. The displaying system includes a linear encoder producing two sets of pulse signals equivalent to the distance and direction of linear movement of the target and circuitry for converting the two sets of pulse signals to a dioptral number of digits, and displaying it. The dioptral number has a plus or minus sign and precision of 0.125 or 0.06 diopters. The displaying system also includes two circuits for displaying at the same time "the power of the sphere" (S) and "the power of the cylinder" (C) of an astigmatic lens respectively as a dioptral number of digits, a rotary encoder and circuitry for displaying "the direction of axis of the cylinder" (Ax) as an angular degree of digits, a (C) sign transposing circuit, and a cylinder form transposing circuit.

Abstract: An improved scanning grating useful as an image scanner and spatial frequency filter, for a focusing detector to ascertain the focus of an optical system on deflecting the light incident from the optical system into two different directions for forming two images of the exit pupil or of parts thereof of said optical system. A slit grating is superimposed over the groove grating so that the ledges cover the peaks and the troughs thereof. It is thereby attained that the signals obtained from the peak and trough areas, which normally are more or less undefined, are exempt from evaluation. The ledges have a width ranging from 10 to 100 percent of that of the slit width.

Abstract: Lens diopter measuring device includes a first and a second diopter scales which have the same but oppositely directed graduations. Correct identification of the diopters of an astigmatic lens can be obtained by bringing the second scale to zero reading at the first focus position and then adjusting the device to the second focus position.

Abstract: Apparatus for measuring the refractive properties of a sphero-cylindrical lens system of the type utilizing an incident light beam scanned in at a predetermined radius about the central axis of the lens system to provide a refracted beam. A generally opaque mask having an annular transparent portion is positioned in the path of the refracted beam, to eliminate errors caused by deviations in radial height from the scanning radius of the refracted beam as it exits the lens system due to refraction within the interior of the optical system. A position-sensitive photodetector generates a signal indicative of the instantaneous position in a given plane due to refraction of the portions of the light beam passing through the mask. The photodetector output signal is then processed to provide an indication of the refractive properties. Various embodiments of the mask are also disclosed. Also permutations of the above including pinhole aperture, input light and other detection means is discussed.

Abstract: A lens meter for analyzing suspect lenses in terms of sphere, cylinder and axis by optical beam deflection and without relatively moving optical parts is disclosed. A light source emanating a substantially collimated beam of light from an entrant aperture into a retroreflecting mechanism includes two important properties. The first property is that an image of the entrant aperture is displayed from and reimaged across the optical axis of the retroreflector to a conjugate location at a real image exit aperture, this aperture being provided with a coincident optical stop. Secondly, in the absence of a test lens in the light path, light entrant to the retroreflector through the entrant aperture along a first path departs the real image of the exist aperture along a second path with a known angularity to the first path.

Abstract: Apparatus for measuring the refractive properties of an optical system of the type utilizing a light beam scanned in a circle or predetermined radius about the central axis of the optical system to provide a refracted beam. A generally opaque mask having specially configured annular transparent portions positioned in the path of the refracted beam to eliminate errors caused by deviations in radial height from the scanning radius of the refracted beam as it exits the optical system due to refraction within the interior of the optical system. A position-sensitive photodetector generates a signal indicative of the instantaneous position in a given plane due to refraction of the portion of the light beam passing through the mask. The photodetector output signal is then processed to provide an indication of the refractive properties.

Abstract: The refractive power(s) of a lens which may possess cylindrical power are determined by retro-reflecting a particular target image through an optical system and varying the axial positioning of one or more elements in the system to bring the reflected image to one or two clear and unambiguous foci at a target plane. By employing a small, intense diffraction image as the target image and further detecting only reflected light passing through a pinhole area on the optical axis at the target plane, a single significant light energy peak is observed at system focus for a lens possessing sphere power only and two significant light energy peaks appear at the respective foci of the principal meridians if the lens also has cylinder power. Means are provided for recognizing the existence, number, and/or relative size of light energy peaks and for correlating their occurrence with the position of the movable element in the optical system to determine respective refractive powers of the test lens.

Abstract: A series of units for manual use or for use in combination with a standard lensometer for evaluating the parameters of soft or flexible contact lenses. The units comprise convexly disposed hemispheres of graduated diameters comprising rigid or semi-rigid material, each of which has a round central aperture and is marked on its convex surface with a series of concentric calibration circles. In preferred form, each of the convex hemispheres is integrally formed with a flat supporting plate, with the convex side protruding and the concave interior having an internal dimension which accommodates any conventional lensometer or similar lens testing instrument. The soft lens whose curvature is to be measured is placed by trial and error on successive inspection and measuring units until the curvature matches or falls between two units of known radii.

Abstract: A lens meter is disclosed in which continuously variable spherical and astigmatic corrective optics are manipulated to measure the prescription of a suspect optical system. A target including a straight line is focused for maximum clarity, the target being arbitrarily aligned without respect to the axis of the suspect optical system. Continuously variable spherical and first astigmatic optics are juxtaposed to the suspect optics and the image of the target projected through both the suspect optics and the continuously variable optics. Spherical and first astigmatic corrections along at least one axis diagonal to the line target is made until maximum sharpness of a projected image of the line results. A first component of astigmatic correction results. A second target, again consisting of a straight line, is introduced; this target is angularly inclined with respect to the first target preferably at 45.degree..

Abstract: The present invention relates to a method and a device for detecting visibility of the image of an object for adjusting the focus of an optical system. The invention is especially suitable to an optical instrument such as camera, using photo-electric conversion elements having non-linear resistance -- intensity of illumination characteristics such as cadmium sulfide CdS or cadmium selenide CdSe, etc. The invention is characterized in that the photo-electric effect of the above mentioned photo-electric conversion elements will have mutually reverse characteristics depending on the properties inherent to the photo-electric conversion elements, to the arrangement of the electrode and the electric circuit, and further on the state of the image of an object formed on said photo-electric conversion elements. An electric circuit to enhance object image visibility is disclosed which makes use of these characteristics.

Abstract: An automatic focusing system is provided for a microscopic instrument having a lens assembly and a platform for supporting an object. The system includes a flying spot scanner, the light from which is directed through the lens assembly at the object. The system includes means responsive to the light directed at the object for generating a signal representative of the color density of the object. The system includes electronic circuitry responsive to the signals and connected to the microscopic instrument for changing the focus of the instrument. The electronic means which are responsive to the signal change the focus of the instrument a plurality of times and includes decision means responsive to the signal for determining the optimum focus and moving the instrument to the optimum focus. The circuitry includes quantization means responsive to the signal which effectively determines the focus position which provides the sharpest resolution of the object examined by the microscopic instrument.

Abstract: A method and device for use in detecting a precise focussing point, which comprises the steps of: placing a photoelectric element on an optical path or optical axis of a lens of a camera; converting the information of the precise focussing point for a photographic object into a frequency variation of an A. C. signal; feeding said signal having varying frequency to a highly sensitive frequency detector such as a resonance circuit, a tuned amplifier, or frequency-amplitude convertor having acute frequency characteristics; and detecting the precise focussing point with high sensitivity by means of the output thus obtained; whereby the aforesaid functions may be satisfactorily performed, irrespective of the variation in the luminance of the object and whereby the focus of the lens may be brought into precise conformity to the predetermined plane (i.e., the position corresponding to a film).

Abstract: A system is described for tracking the position of a light source by mounting two orthogonal triangular interferometric systems on a gimbaled platform. The interferometric systems each provide a carrier frequency signal depending upon their pointing angle with respect to the light source. These carrier signal frequencies provide the error signals for the X and Y axis drives of the platform.

Abstract: Apparatus for measuring the frontal power of corneal contact lenses made of a somewhat hydrophilic material and having a predetermined index of refraction in a liquid having itself a predetermined index of refraction. This apparatus comprises a sighting optical system and a measuring optical system spaced from each other and having a common optical axis extending substantially vertically at least in the gap between said two optical systems. It further comprises a small cup disposed in said gap and filled with said liquid, the cup bottom comprising a fluid-tight window centered to said optical axis and means for supporting a contact lens in said liquid in a position centered to said optical axis.

Abstract: A device for automatically measuring the spherical power, cylindrical axis and power and prism of an ophthalmic lense, with each determined independently of each other without a servo system. At least two LEDs act as point-sources of light, as Scheiner apertures. The light from the LEDs pass through an objective lense, thence through a selectively translatable aperture target, and then pass through a collimating lense. The LED rays then pass through the lens under study, and the target images are focused by a telescope objective lens onto a light sensitive detector. The detector which is selectively rotatable in concert with the LEDs is partitioned into Cartesian quadrants. Rotation of the detector and LEDs until the target images fall on the major detector axis discloses the axis of the cylinder of the lens being measured independent of lens power. Translation of the target until the target images maximally coincide reveals the power of the lens in its principal meridian.

Abstract: In an opto-electronic focus detection system for determining a deviation between the plane of focussing of an objective and a radiation-reflecting surface the path of a focussing beam which is reflected by said surface includes an assembly of two radiation-sensitive detection elements. The difference in the output signals of said elements is proportional to said deviation. By disposing a lenslike element of which only the outer zone has a lens action before the detection elements, the measuring range can be extended while maintaining the sensitivity for small deviations.

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: A mechanism for determining the focus by an objective lens of an image on a focal plane includes a needle shaped or other narrow scanning mask transversely oscillated in the focal plane between the lens and a transversely extending photoelectric element exposed to the mask intercepted image. The output of the photosensitive element is coupled by way of a high pass filter or differentiating circuit and a rectifier to a meter, the maximum meter reading indicating maximum AC output and hence maximum focus. The output of the photosensitive element is also connected through a low-pass filter to a meter or exposed control mechanism.

Abstract: A photoelectric focus detecting member includes a semiconductor substrate of a first polarity and at least two closely transversely spaced parallel longitudinally extending photosensitive laminae of a polarity opposite to the first polarity to form corresponding photodiodes. Each of the photosensitive laminae is masked to provide regularly spaced light receiving areas alternating with masked areas, the light receiving areas of successive transversely spaced photodiodes being relatively longitudinally offset to present a checkered pattern. The detecting element is positioned in the focal plane of a lens and is either stationary or oscillated. The difference in potential between the diodes or the amplitude of the AC current in a circuit including the photodiodes is a function of the condition of focus of the lens.