Abstract: A lens testing device comprises a holder, fitted on a stand, for mounting a lens specimen, a test object illuminated from the rear, an imaging objective and a detector for evaluating the image of the test object. The imaging objective can be combined with the detector to form a unit. The lens specimen is an objective specimen and the test object is arranged in the focal plane of the objective specimen inside the holder. The imaging objective is a collimator objective and the detector is arranged in the focal plane of the collimator objective. Either the holder or the unit is pivotably supported on the stand and the holder and the unit can be pivoted relative to one another.

Abstract: In a distortion measuring method, a mask having at least a first diffraction grating pattern having an array of a plurality of large patterns and a second diffraction grating pattern having arrays of a plurality of micropatterns spaced apart from the first diffraction grating pattern by a predetermined interval is formed. The plurality of micropatterns are arrayed in a direction perpendicular to an array direction of the second diffraction grating pattern at a predetermined pitch. At least the first and second diffraction grating patterns formed on the mask are projected on a photosensitive substrate through a lens. Distortion including a positional shift component of an image point by aberration of the lens is measured by scanning the photosensitive substrate using coherent light having a diffractable wavelength and by measuring an interval between at least the first and second diffraction grating patterns. A distortion measuring apparatus and reticle are also disclosed.

Abstract: A method of determining aberration of an optical imaging system comprises measuring at least one parameter, such as position of best-focus and/or lateral position, of an image formed by the imaging system. This is repeated for a plurality of different illumination settings of the imaging system, and from these measurements at least one coefficient, representative of aberration of said imaging system, is calculated.

Abstract: Two coma aberration automatic measuring marks M1 and M2 of a first-order diffraction grating are each composed of a plurality of elongated isosceles triangle patterns which are so arranged that the axis of symmetry passing on the center of each elongated isosceles triangle is parallel to one another, that a half P1, P2, and P3 of the elongated isosceles triangle patterns have the widths thereof which extend in a direction opposite to that of the remaining half P4, P5 and P6 of the elongated isosceles triangle patterns, and the elongated isosceles triangle patterns are located separately from one another, in a direction perpendicular to the axis of symmetry passing on the center of each elongated isosceles triangle, and at a pitch diffracting a measuring coherent light.

Abstract: An optical measuring apparatus used for measuring optical characteristics of a liquid crystal display panel (LCD panel) in a calibration thereof comprises a housing having a contacting portion directly contacting a surface of the LCD panel and disposed far from a region on the LCD panel to be measured. An optical system and a photosensor is provided in the housing with a predetermined positional relation, so that ambient illumination is shielded by the housing and stray rays emitted from the LCD panel and having exit angles larger than a predetermined maximum exit angle &agr; are restricted by the optical system.

Abstract: An aberration detector for easily detecting aberration of a lens in a short time period by utilizing an interferometer. The aberration detector includes a laser diode, a beam splitter for dividing a light beam into two light beams, an optical system for supporting a lens and converging a light beam passing through the lens to a converging point, a spherical mirror for reflecting the light beam passing through the lens, an image pickup element for detecting an interference pattern obtained by interference of a reference light and the light reflected on the spherical mirror, and an analyzer for analyzing the interference pattern. A center of a sphere constituting the spherical mirror is arranged in a position displaced from the converging point such that a plurality of circular fringes are concentrically arranged on the interference pattern.

Abstract: A system is provided for producing a high contrast image of features of an optical component. In the system of the present invention, light is focused through the optical component prior to reaching the detector of an image sensing means.

Abstract: There is provided a method of measuring spherical aberration in a projection system in which a mask pattern is projected in a reduced scale with a light having a wavelength of &lgr;, including the steps of (a) projecting a first mask pattern onto a photosensitive object in a reduced scale, the first mask pattern being defined by light-permeable portions and light-impermeable portions each sandwiched between the light-permeable portions, each of the light-permeable portions having a width equal to the wavelength &lgr;, (b) projecting a second mask pattern onto the photosensitive object in a reduced scale, the second mask pattern being defined by light-permeable portions and light-impermeable portions each sandwiched between the light-permeable portions.

Abstract: A system is provided for producing a high contrast image of features of an optical component. In the system of the present invention, light is focused through the optical component prior to reaching the detector of an image sensing means. In addition, a novel cuvette is provided for holding and locating an optical component in position during inspection. The cuvette comprises a bottom portion having a concave curved inner surface for utilizing the force of gravity to hold an optical component in place.

Abstract: The invention provides an inspection cell for inspecting an ophthalmic lens. The inspection cell is a solid block that has a bottom planar surface, a top surface, and an indentation in the top surface. The indentation is adapted to receive an ophthalmic lens, which is to be inspected. The invention additionally provides an inspection unit for an ophthalmic lens, which holds one or more of the inspection cells.

Abstract: Vision in an eye is corrected using an energy source for generating a beam of optical radiation and focusing optics disposed in the path of the beam for directing the beam through the eye, where the beam is reflected back from the retina of the eye as a wavefront of radiation to be measured. An optical correction based on an optical path difference between the measured wavefront and a desired plane wave, and refractive indices of the media through which the wavefront passes is provided to a laser delivery system with a laser beam sufficient for ablating corneal material from the cornea of the eye. The laser beam is directed at selected locations on the cornea for ablating the corneal material in response to the optical correction to cause the measured wavefront to approximate the desired plane wave, and thus provide an optical correction.

Abstract: Vision in an eye is corrected using an energy source for generating a beam of optical radiation and focusing optics disposed in the path of the beam for directing the beam through the eye, where the beam is reflected back from the retina of the eye as a wavefront of radiation to be measured. An optical correction based on an optical path difference between the measured wavefront and a desired plane wave, and refractive indices of the media through which the wavefront passes is provided to a laser delivery system with a laser beam sufficient for ablating corneal material from the cornea of the eye. The laser beam is directed at selected locations on the cornea for ablating the corneal material in response to the optical correction to cause the measured wavefront to approximate the desired plane wave, and thus provide an optical correction.

Abstract: The invention provides an inspection cell for inspecting an ophthalmic lens. The inspection cell is a solid block that has a bottom planar surface, a top surface, and an indentation in the top surface. The indentation is adapted to receive an ophthalmic lens, which is to be inspected. The invention additionally provides an inspection unit for an ophthalmic lens, which holds one or more of the inspection cells.

Abstract: A lens specifying apparatus comprising a light source (21) for projecting a measuring light beam on a lens (30) under examination, an area CCD (35) image receiving element for receiving the measuring light beam transmitted by the lens (30) under examination, a filter disc (64) disposed, as means for providing spectral transmittances, at a midpoint of an optical path extending from the light source (21) to the area CCD (35), and a processing circuit (37) for calculating the refractive characteristics and spectral transmittances of the lens (30) under examination on the basis of an output of the area CCD (35) and displaying the refractive characteristics and spectral transmittances on a monitor (3).

Abstract: A lens meter is provided which comprises a light source for generation of a measuring light beam and a pattern forming plate provided in an optical path of the measuring light beam. The pattern forming plate has a central pattern for measuring lens characteristics of a narrow area on an eyeglass lens and a plurality of peripheral patterns for measuring lens characteristics of a wide area on the eyeglass lens. The pattern forming plate can be switched between a normal measuring mode which receives the image of the central pattern based on the measuring light beam transmitted through the narrow area of the eyeglass lens and also measures the narrow area alone and displays the measured values and a wide-area measuring mode which receives a great number of images of the peripheral patterns based on the measuring light beam transmitted through the wide area of the eyeglass lens and also measures the wide area and performs mapping display.

Abstract: The optimum optical properties of a spectacle lens that correspond with the state in which the spectacle lens is worn by respective wearers are found and evaluated. Three-dimensional shape data of the spectacle lens comprising the determinations of a three-dimensional determination device that determines the surface shape f the spectacle lens, parameters of the state in which the spectacle lens is worn, such as the distance from the center of rotation, and material parameters, such as the refractive index of the spectacle lens, are input to a computer that calculates optical properties of a spectacle lens.

Abstract: A holder is constructed of a cylindrical member made of a metal and an inward flange member made of a diffusion transparent member. The inside of the cylindrical member is sectioned into a tapered area whose inside diameter decreases downward, and a small-diameter cylindrical area and a large-diameter cylindrical area. The inward flange member is bonded to the bottom end of the small-diameter cylindrical area.

Abstract: A method of determining optical quality of a transparent product includes passing a first gray-scale pattern through the material; obtaining a first image of the first pattern with an image pickup device after the first pattern has passed through the material; and determining optical quality of the material based on data obtained from the first image. An apparatus for determining optical quality of such a material is also disclosed.

Abstract: A system for inspecting intraocular lenses which utilizes a light source and an electronic camera for obtaining images of the lens under test. A series of masks is utilized during the obtaining of the images and includes a bright field mask which allows the transmission of light through the lens, a dark field mask which blocks a portion of the light which would normally pass through the lens and a transition mask which is constituted by fine stripes. A signal processor analyzes the images obtained utilizing the masks and provides an indication of predetermined defects in the lens.

Abstract: Improved systems, methods, and apparatus for calibrating a laser ablation system by measuring the optical power and shape of a test surface that has been ablated by energy delivered from a laser. The quality of the ablated test surface can be monitored to minimize undesirable laser system performance, such as might result from flawed internal optics, misalignment, poor laser fluence and the like. Calibration accuracy is generally enhanced by analyzing distortions of a geometrical pattern superimposed with the ablation test surface. The interaction of the pattern and the lens can be analyzed using a microscope, video camera connector, and other existing components of the laser ablation system, and can also provide quantitative test surface characteristics which may be used to accurately adjust the laser system.

Abstract: An assemblage and method for testing a lens having a plurality of field angles employs an improved modulation transfer function (MTF) design system for evaluating image quality produced by the lens being tested. A reflecting surface capable of translational and rotational movements is arranged along a predetermined optical path for receiving a collimated array of light rays and then directing the collimated array of light rays to the lens being tested.

Abstract: A system for inspecting ophthalmic lenses and including transport, illumination, imaging and image processing subsystems. The transport system moves a multitude of ophthalmic lenses along a predetermined path to move each of those lenses, one at a time, into a lens inspection position, and the illumination subsystem generates a series of light pulses and directs a respective one light pulse through each ophthalmic lens. The imaging subsystem generates a set of signals representing selected portions of the light pulses transmitted through the ophthalmic lenses, and the image processing subsystem receives those signals from the imaging subsystem and processes those signals according to a predetermined program to identify at least one condition of each of the lenses.

Abstract: A refractometer and a method for measuring the refractive index of a lens, wherein a thin insert in the form of a pad of a flexible transparent material attached to a rigid transparent sheet, is lightly pressed onto a surface of the lens under test, such that the pad surface effectively acquires the same profile as the lens surface. The focal length or power of the lens is first measured without the insert, and the measurement is then repeated with the insert positioned first in contact with one surface of the lens, and then in contact with the other surface. The use of equations derived from the classical lens formula then enables the refractive index of the lens to be easily and quickly determined. The apparatus and method also enables the measurement of the refractive index of lenses of low power.

Abstract: In a contact lens visual inspection method and apparatus, a contact lens insertion portion of a container is first imaged by an image pickup device and then an area which locates on the container and is unnecessary for the visual inspection of a contact lens is extracted from the image of the contact lens insertion portion to form a mask image. Thereafter, a system containing the contact lens insertion portion of the container, the preservation liquid filled in the contact lens insertion portion and the contact lens placed in the contact lens insertion portion is imaged as an inspection object by the imaging device to obtain an inspection object image, the inspection object image is overlapped with the mask image, and the mask image is subtracted from the inspection object image to set as a visual inspection area the area corresponding to a subtracting image obtained by said subtracting step. The defects of the contact lens such as soil, foreign matter, scratch, breakage, peripheral damage, etc.

Abstract: A device and method to prepare a stepper to form semiconductor structure lines by using a calibration reticle to determine optimum numerical aperture and partial coherence values for the stepper. The calibration reticle includes a light-transmissive substrate having a plurality of patterns disposed thereon, each of the plurality of patterns including a series of structures of a constant size spaced an equal distance from one another and having a predetermined pitch intended to mimic a pitch value of a semiconductor structure reticle. The method includes positioning the calibration reticle on a stepper and optimizing the performance characteristics (e.g., the partial coherence value and the numerical aperture value) of the stepper using one of the patterns of the calibration reticle corresponding to a predetermined pitch of a semiconductor structure reticle.

Abstract: A lens meter is provided which includes a light source portion which emits measuring light having at least three different wavelengths; a light receiving portion which receives the measuring light which has passed through a to-be-inspected lens immersed in a liquid as a medium; an in-medium optical characteristic measuring device for measuring an optical characteristic of the lens in the medium about each wavelength, based on a deviated quantity of the measuring light detected by the light receiving portion; a refractive index calculating device for calculating a refractive index of material of the lens, based on a difference of the optical characteristic of the lens in the medium among the wavelengths; and a converting device for converting the optical characteristic of the lens in the medium into an optical characteristic of the lens in the air, based on the refractive index calculated by the refractive index calculating device.

Abstract: A method of determining reflective optical quality of a reflective product includes reflecting a first gray-scale pattern off the product; obtaining a first image of the first pattern with an image pickup device after the first pattern has reflected off of the product; and determining optical quality of the product based on data obtained from the first image. An apparatus for determining reflective optical quality of such a product is also disclosed.

Abstract: Exposures of a photosensitive material through an array of blazed gratings illuminate a lens asymmetrically to detect effects of a plurality of azimuthal aberrations including coma, astigmatism, and three-leaf and four-leaf clover aberrations. A plurality of such exposures of the array of blazed gratings at slightly differing focus allows detection of focus shift due to any aberrations present in the lens. Upon development of the plurality of exposures, contrast of each area is measured, for example, by reflection or scattering from the relief in the developed photosensitive material and the aberrations thus detected can be simulated by effective summation of individual aberration effects.

Abstract: An apparatus for detecting parameters of an ophthalmic lens including a vertex refractometer having a lens support for the ophthalmic lens and a detection device for optical detection of at least one engraved marking on at least one predetermined surface area of the ophthalmic lens. The vertex refractometer has a measurement beam path which passes through the ophthalmic lens when the ophthalmic lens is lying on the lens support and the detection device has at least one light source, an imaging optical system for directing light from the at least one light source onto the at least one predetermined surface area of the ophthalmic lens with at least one engraved marking, and an optical receiver system having a light sensor which is connected to an evaluation and representation unit. The optical receiver system images light beams from the imaging optical system which are reflected from the at least one predetermined surface area of the ophthalmic lens.

Abstract: According to one aspect of the present invention, a method for determining orientation of one surface of an optical component relative to another surface of the optical component comprises: (a) placing the optical component into a test fixture having certain characteristics from which differences in test fixture orientation and position can be determined, so that the one surface of the optical component is accessible in one orientation of the test fixture and the other surface of the optical component is accessible in another orientation of the test fixture; (b) measuring surface profile and orientation of the one surface of the optical component with the test fixture in one orientation; (c) measuring surface profile and orientation of the second surface of the optical component with the test fixture in second orientation; and (d) determining profile and relative orientation of the one surface of the optical component with respect to the another surface of the optical component by nulling out differences betw

Abstract: An instrument and method for optical testing of an eyeglass lens, including progressive addition lenses, to obtain image quality measurements includes an illumination system for presenting a beam of light to a test lens, a test lens positioning system for rotating the test lens so that different areas on the lens are illuminated, a zoom lens for focusing the beam at a constant effective focal length, a detection system for recording and measuring image quality of the test lens, and an alignment boom for conveying the zoom lens and the detection system such that the optical axis remains aligned with the beam existing the test lens. The instrument is fully automated and capable of obtaining measurements of the power, astigmatism, prism and modulation transfer function at various locations on the surface of the lens.

Abstract: A method and apparatus of generating a test signal for broadcast to a plurality of locations for testing optical devices is disclosed. A tunable laser sweeps from a lower wavelength to a higher upper wavelength providing a test station with a variable input signal. A timing signal generated from the variable input signal is provided to the test station to determine the frequency of the variable input signal so that tests may be performed at several known wavelengths. Amplification is added to the system to provide sufficient power to the variable input signal and timing signal both split by a splitter to be provided to multiple test stations simultaneously.

Abstract: A lens meter is provided in which a measurement light beam emitted from a light source (21) is projected onto a lens (L) to be inspected, an amount in travel of the measurement light beam which has passed through the lens (L) is then detected by a TV camera (34), and the refractive characteristics of the lens (L) based on the detection result are computed by an arithmetic and control circuit (35) and are displayed by a display unit (3). In the lens meter, the arithmetic and control circuit (35) computes cylindrical power of a distance portion (40) of the lens (L) in consideration of cylindrical power and a direction of a cylindrical axis from the detection result of the TV camera (34), and then computes cylindrical power in distortion areas (42, 43) except the distance portion (40), a progressive portion (41), and a near portion (41') in consideration of the cylindrical power and the direction of the cylindrical axis.

Abstract: The present invention provides a method of detecting a lens aberration in a semiconductor production process, comprising the steps of:forming a feature on a substrate by a process including a step of exposing a radiation-sensitive material to radiation, wherein said radiation passes through a lens;obtaining data relating to a sidewall angle at a plurality of adjacent locations of said feature by scanning at least one surface of said feature with an atomic force microscope;calculating the sidewall angle at said plurality of adjacent locations of said feature based on the data obtained by the atomic force microscope;comparing the sidewall angle obtained from the calculation step to a design sidewall angle for a lens free of aberration, thereby detecting the lens aberration when the comparison reveals a substantial difference between the calculated side wall angle and the design sidewall angle; andidentifying a lens position of the lens aberration by extrapolating from the locations of said feature having said s

Abstract: The present invention relates to a method for characterizing at least one photorepeater and a same set of patterns implemented on several regions of a wafer, including the steps of making a standard reticle defining at least one first series of at least three identical reference patterns, which are not aligned; successively exposing several regions of a standard wafer by varying the illumination dose from one region to another; measuring the respective dimensions of the reference patterns reproduced on the different regions of the wafer to determine, for each illumination does, the mean dimension of the reference patterns; and performing a linear interpolation of these mean dimensions.

Abstract: A lithographic process for semiconductor device fabrication is disclosed. In the process a patterned mask having a multilayer film formed on a substrate is illuminated by extreme ultraviolet (EUV) radiation and the radiation reflected from the pattern mask is directed onto a layer of energy sensitive material formed on a substrate. The image of the pattern on the mask is thus introduced into the energy sensitive material. The image is then developed and transferred into the underlying substrate. The multilayer film is inspected for defects by applying a layer of energy-sensitive film (called the inspection film) in proximity to the multilayer film and exposing the energy-sensitive material to EUV radiation. The thickness of the multilayer film is such that a portion of the EUV radiation is transmitted through the inspection film, reflected from the multilayer film and back into the inspection film.

Abstract: A fringe deflectometry apparatus illuminates an optical component to be measured using radiation with a known wavefront, deflects the radiation after it has been reflected or transmitted by the optical component to be measured, and materializes a reference ray. Transverse aberration of the reference ray after reflection or transmission by the optical component is measured. A deflectometry method using the apparatus enables an absolute phase reference to be provided.

Abstract: A method for precise design of light distribution for lighting equipment that use light-emitting devices, and for subsequently producing such equipment. By modeling the internal structure of an LED device with respect to the geometry and characteristics of a chip portion, chip reflector and lens portion, illuminating light from an LED device is classified into direct light from the chip portion and the reflected light from the chip reflector. The unknown values necessary for the modeling are specified preliminarily by actual measurements. Subsequently, the original geometry of the lens step is determined roughly based on the target direction and the diffusion angle of the light transmitted through the step. The manner in which the direct light from the chip portion and the reflected light from the chip reflector are transmitted through the lens portion and the lens step is simulated by ray tracing.

Abstract: An optical member inspection apparatus is disclosed. A light shielding plate functions to cast a shadow region so that a line sensor receives an image producing a particular defined image data output, generally speaking a dark image representing an absence of light from an illuminator. When an inspection target optical member is inserted in the light path to intersect that shadow region, the line sensor produces the same image data in the event that there is no defect in the optical member. However, a defect in the optical member will enable light from outside that shadow region to be diffused to impinge on the line sensor thereby producing a change in the image data output. Evaluation of the change in the image data output can provide an indication of the degree of defectiveness.

Abstract: A dry zeroing assembly is provided for zeroing a gun-sight implemented on a gun having a barrel.

Abstract: In a method for evaluating the homogeneity of the refractive index of an optical member, the refractive index distribution of the optical member is measured, the measured refractive index distribution is separated into a rotationally symmetric element and a non-rotationally symmetric element in the optical axis direction before or after correction of the power element, and the rotationally symmetric element is further subjected to 2nd/4th-order element correction. Upon execution of such comprehensive evaluation, a photolithography optical member, which can realize a fine, sharp exposure-transfer pattern (e.g., a line width of 0.3 .mu.m or less) is provided.

Abstract: A non-contacting measuring method for three dimensional micro pattern in a measuring object is disclosed. Three dimensional micro pattern of the surface of the measuring object is measured using blur of light. For measurement, a mechanism of an optical window with a slit is inserted between light source and the measuring object. The blurred image is captured by charge coupled device sensor based image frame grabber, and is analyzed in personal computers. All the values of the relative height differences are obtained in overall scanning measurement area of the measuring object. The relative height differences are the distances from the reference position to the other positions. The reference position is selected when its image is sharp in focus on the screen. At this time, images of the other positions except the reference position are blurred out of focus on the screen.

Abstract: A system for inspecting ophthalmic lenses and including transport, illumination, imaging and image processing subsystems. The transport system moves a multitude of ophthalmic lenses along a predetermined path to move each of those lenses, one at a time, into a lens inspection position, and the illumination subsystem generates a series of light pulses and directs a respective one light pulse through each ophthalmic lens. The imaging subsystem generates a set of signals representing selected portions of the light pulses transmitted through the ophthalmic lenses, and the image processing subsystem receives those signals from the imaging subsystem and processes those signals according to a predetermined program to identify at least one condition of each of the lenses.

Abstract: A reticle consisting of a multiplicity of small openings corresponding to separate and distinguishable points is put in the reticle plane. This reticle is imaged down through an opening O in aperture plate AP. A corresponding multiplicity of spots are created at the image plane of the optical system. These spots have spot centroids relative to the original separate and distinguishable points in the reticle. These points, however, are deviated from their diffraction limited positions by the average of grad.phi.(u)) over the corresponding ray bundle. The opening O in the aperture plate samples a discrete portion of the entrance pupil. With points spread out over an area of size 2*NAo*za, ray bundles with chief rays covering the entire entrance pupil will be projected down to image plane IP. The above outlined procedure is extended to analyzing the wavefront at a multiplicity of field points over the entire lens train. The process includes using an aperture plate AP consisting of a multiplicity of openings O.

Abstract: A lens specifying apparatus is provided which includes a lens meter (1) for measuring and obtaining the lens refraction characteristic distribution information of a subject lens (30), an information recording/regeneration unit (104) on which lens information has been recorded, an arithmetic control circuit (101a) for comparing the lens refraction characteristic distribution information measured by the lens meter (1) with the lens information recorded on the information recording/regeneration unit (104) and judging to which lens information the measured lens refraction characteristic distribution information corresponds.

Abstract: A lens distortion measurement system has a first grating of a first pitch on a transparent support such as a quartz reticle. The reticle is disposed between an illumination source and the lens system whose distortion is to be measured. An image sensor is provided within the image projection field of the lens system. A second grating of a second (different) pitch is provided on another transparent support, disposed between the lens system and the image sensor. Optionally, a relay lens is disposed between the second support and the image sensor. Illumination propagates from the illumination source through the first support, through the lens system, through the second support and is incident on the image sensor. The illumination forms a Moire fringe having a pitch orders of magnitude greater than the pitches of the first and second gratings.

Abstract: On a monitor (52) there is displayed a synthesized image (G4) in which an image (G1) of a subject lens showing a refractive power distribution, an image (G2) of a lens frame, and an eyepoint mark image (G3) are superimposed based on the refractive power distribution data of the subject lens by a lens meter (100), on the frame shape data of the lens frame by a frame shape measurement apparatus (200), and on the eyepoint data by an eyepoint measurement apparatus (300).

Abstract: A method (100) of separating linewidth variations due to reticle generation defects from other linewidth variations at a substrate surface during a pattern transfer process includes generating (102) a test reticle (200) having a first plurality of structures (204) forming a first pattern (202). The method further includes measuring a dimension (104) of two or more of the first plurality of structures (204) on the test reticle (200), thereby creating (106) a first data set representing linewidth variations due to the test reticle generation. A second pattern is transferred (108) to the surface of the substrate, wherein the second pattern includes a second plurality of structures which substantially correspond to the first plurality of structures and a dimension of two or more of the second plurality of structures (110) are measured, thereby creating (112) a second data set representing the linewidth variations at the surface of the substrate.

Abstract: A testing apparatus for an optical system comprises a plurality of markers disposed along an axis to be aligned with the optical axis of the optical system, the markers being axially spaced from one another and angularly displaced relative to one another so as to effectively define a helix about the axis. When viewed from one end of the apparatus the markers provide focusing and depth of field information, and some aberrational information about the optical system. Preferably the markers are spaced so as to correspond to the depth of field of the lens aperture stop values of a camera, allowing the aperture settings of the camera to be tested.

Abstract: The present invention is a method of rating eyewear according to their solar radiation protective capabilities. Measured ultraviolet (UV), blue light (BLUE), and reflective and blocking properties (STYLE) of eyewear are transformed into a substantially linear numerical value. The ultraviolet and blue light values provide information about the absorptive properties of eyewear lenses. The UV and BLUE values provide information about the absorptive properties of the lenses while style provides information about the light blocking properties of the frames. These values are then placed upon rated eyewear, thus allowing consumers the ability to make more informed decisions when shopping for protective eyewear.