Abstract: An optical component focus testing apparatus includes a plurality of test pattern displays. One or more illuminators are configured to selectively illuminate different test pattern displays at different times. Light directors are provided to direct light from at least one of the illuminated test pattern displays towards an optical component under test. The light directors and test pattern displays are arranged such that, in use, light directed from different illuminated test pattern displays travel different distances to reach the optical component under test.

Abstract: A lens meter having a measurement-optical system including a light source which projects and a light-receiving sensor which receives a light beam having passed through the lens; an arithmetic part which obtains optical characteristics of the lens from results received by the light-receiving sensor; mode selecting device which selects between a single-focal-lens-measurement mode and a progressive-lens-measurement mode; detecting device which detects directions and degrees of displacement of measurement positions from a near-vision portion of a progressive lens based on optical characteristics obtained when the progressive-lens-measurement mode is selected and alignment is made to bring the measurement position into the near-vision portion; a display which displays an alignment screen; and a display-control part which causes the display, based on detection results by the detection device, to display a guide mark indicating a direction and an amount that the lens must be moved to bring the measurement position i

Abstract: A method of using an in-situ aerial image sensor array is disclosed to separate and remove the focal plane variations caused by the image sensor array non-flatness and/or by the exposure tool by collecting sensor image data at various nominal focal planes and by determining best focus at each sampling location by analysis of the through-focus data. In various embodiments, the method provides accurate image data at best focus anywhere in the exposure field, image data covering an exposure-dose based process window area, and a map of effective focal plane distortions. The focus map can be separated into contributions from the exposure tool and contributions due to topography of the image sensor array by suitable calibration or self-calibration procedures. The basic method enables a wide range of applications, including for example qualification testing, process monitoring, and process control by deriving optimum process corrections from analysis of the image sensor data.

Abstract: A method of measuring a zoom ratio of a projection optical system adapted to project image light representing an original image on a projection screen, the method includes: (a) projecting and displaying a measuring image including a measurement point on the projection screen so that the measurement point is displayed at a position with an offset from an optical axis of the projection optical system; (b) detecting a projected measurement point, which is the measurement point projected and displayed on the projection screen, from a measurement point detection position having a fixed position relative to the projection optical system; and (c) determining the zoom ratio using position information of the detected projected measurement point and correspondence between the position information and the zoom ratio, the correspondence being prepared previously.

Abstract: A lens power measuring system has a light source and a fiber-optic light delivery system optically coupled to the light source to receive illumination light from the light source. The fiber-optic light delivery system has a transmit/receive end. The lens power measurement system also has a microscope objective optically coupled to the fiber-optic light delivery system through the transmit/receive end of the fiber-optic light delivery system, a movable mirror arranged to intercept at least a portion of light after having passed through the microscope objective, and an optical detection system optically coupled to the fiber-optic light delivery system to receive light after having been reflected from said movable mirror. The optical detection system is constructed to be able to determine a substantially maximum signal of light reflected from the movable mirror in correspondence with a relative position of the movable mirror to a lens to be measured.

Abstract: A focusing method is provided for the high speed digitalization of microscope slides using an imaging device, wherein the slide is divided into fields of view according to the imaging device and focusing is performed. During rough focusing, several images are captured within the focus range using large focus steps. On the basis of this set of images the position of the best contrast is determined. Fine focusing is performed by adjusting the focus according to the focus distance already determined for another field of view and by focusing with fine steps. A slide displacing device is provided, which enables the displacement of a slide parallel to the optical axis. The slide displacing device includes slide holding elements affixed to one side of a supporting member having two parallel sides, which are connected by stiffening elements defining at least two parallel planes.

Abstract: A method and system for measuring an optical property of a multi-focal lens are disclosed. One embodiment of the method comprises: filtering out light transmitted by all but one of a plurality of diffraction orders of the lens to provide an unfiltered light from a single diffraction order; receiving the unfiltered light at a wavefront detector; and analyzing the unfiltered light at the wavefront detector to measure the optical property. The multi-focal lens can be a multi-focal diffractive intra-ocular lens. The measured optical property can be a discontinuity in the lens surface. Filtering can comprise blocking all but the unfiltered light using an aperture operable to let through the unfiltered light from the single diffraction order, and/or blocking all but the unfiltered light using an opaque obstruction operable to let through only a selected amount of light corresponding to the light transmitted by the single diffraction order.

Abstract: Methods to at least partially compensate for photoresist-induced spherical aberration that occurs during mask imaging used for photolithographic processing of semiconductor devices, LCD elements, thin-film magnetic heads, reticles and other substrates including photo-defined structures thereon are disclosed. A photoresist or other photosensitive material may be irradiated with a mask pattern image including a selected nonzero spherical aberration value to compensate for photoresist-induced spherical aberration.

Abstract: A system for checking centration of lens surfaces of an aspheric lens includes a light-emitting device, a lens holder and an image processing device. The light-emitting device emits a light. The lens holder positions the aspheric lens in a light path of the light emitted from the light-emitting device. The image processing device receives the light which is emitted from the light-emitting device and has passed through the aspheric lens, and produces an image and shows the image. A quality of the image shown by the image processing device determines a tilt degree of the aspheric lens.

Abstract: A method for determining one or more process parameter settings of a photolithographic system is disclosed.

Abstract: A lens meter for measuring optical characteristics of a lens to be measured includes a measurement optical system including a light source which projects a measurement light beam to the lens and a light receiving sensor which receives the measurement light beam having passed through the lens; an arithmetic part which obtains optical characteristic distribution of a predetermined measurement region of the lens based on a light reception result of the light receiving sensor; near-vision-portion determination means which determines whether a near vision portion of the lens is present in the measurement region based on the optical characteristic distribution in the measurement region; and detection means which detects presence of a non-optical region in addition to an optical region of the lens in the measurement region based on the light reception result of the light receiving sensor; the arithmetic part obtains additional power of the lens based on the optical characteristic distribution of the optical region i

Abstract: A method of manufacturing an optical component comprising a substrate and a mounting frame with plural contact portions disposed at predetermined distances from each other is provided. The method comprises providing a measuring frame separate from the mounting frame for mounting the substrate, which measuring frame comprises a number of contact portions equal to a number of the contact portions of the mounting frame, wherein respective distances between the contact portions of the measuring frame are substantially equal to the corresponding distances between those of the mounting frame, measuring a shape of the optical surface of the substrate, while the substrate is mounted on the measuring frame, and mounting the substrate on the mounting frame such that the contact portions of the mounting frame are attached to the substrate at regions which are substantially the same as contact regions at which the substrate was attached to the measuring frame.

Abstract: Provided are a three-dimensional image measuring method and apparatus for an LCD color filter automatic grinder. It is possible to measure a three-dimensional image of an LCD color filter, even though textures for recovering the three-dimensional image are insufficient, by irradiating illumination passed through a patterned filter to the LCD color filter. In addition, it is possible to measure a three-dimensional image of an LCD color filter by obtaining a plurality of image sequences along an optical axis of a camera composed of CCD or CIS. Illumination is irradiated to an LCD color filter to be measured through a patterned filter.

Abstract: An apparatus for measuring characteristics of a substance is provided. The apparatus includes a light source to generate light to form an image. A splitter transmits the light from the light source to a first lens, which collimates the light. A second lens receives the collimated light and is adapted to oscillate with respect to the substance and adapted to transmit and focus the light to a focal region within the substance, such that the oscillation will cause the focal region to pass back and forth through the substance and its surfaces/interfaces. A sensor receives light reflected from the focal region and provides a signal indicative of characteristics of the substance at the focal region.

Abstract: A cup attaching apparatus for attaching a cup as a processing jig to an eyeglass lens, comprises: an illumination optical system comprising an illumination light source and arranged to illuminate the lens from a side of a front surface of the lens by illumination light from the light source; an imaging optical system comprising an imaging device and a retroreflection member placed on an opposite side from the light source with respect to the lens, the imaging optical system being adapted such that the retroreflection member returns the illumination light passing through the lens back to its incoming direction, and the imaging device receives the returned illumination light, and the imaging optical system being adjusted to focus on a point near a surface of the lens; an image processing device adapted to process an image signal from -the- imaging device to detect at least one of a mark point provided on a unifocal lens, a small lens portion of a bifocal lens, and a progressive mark provided on a progressive fo

Abstract: A lens power measuring system has a light source and a fiber-optic light delivery system optically coupled to the light source to receive illumination light from the light source. The fiber-optic light delivery system has a transmit/receive end. The lens power measurement system also has a microscope objective optically coupled to the fiber-optic light delivery system through the transmit/receive end of the fiber-optic light delivery system, a movable mirror arranged to intercept at least a portion of light after having passed through the microscope objective, and an optical detection system optically coupled to the fiber-optic light delivery system to receive light after having been reflected from said movable mirror. The optical detection system is constructed to be able to determine a substantially maximum signal of light reflected from the movable mirror in correspondence with a relative position of the movable mirror to a lens to be measured.

Abstract: A metrology system performs optical metrology while holding a sample with an unknown focus offset. The measurements are corrected by fitting for the focus offset in a model regression analysis. Focus calibration is used to determine the optical response of the metrology device to the focus offset. The modeled data is adjusted based on the optical response to the focus offset and the model regression analysis fits for the focus offset as a variable parameter along with the sample characteristics that are to be measured. Once an adequate fit is determined, the values of the sample characteristics to be measured are reported. The adjusted modeled data may be stored in a library, or alternatively, modeled data may be adjusted in real-time.

Abstract: A shape value of a pattern having a pivotal characteristic is measured (step S1), an exposure energy variation is detected from the measured value, a first data base is accessed using a result of the measurement of the shape value (Step S2), an exposure energy is calculated (Step S3), a shape value of an isolated pattern is measured (Step S4), a second data base is accessed using a result of the measurement (Step S5), and a focal variation is determined using the calculated proper exposure energy (Step S6).

Abstract: A method for determining at least one of distortion and de-focus for an optical imaging system. The method includes determining wavefront aberrations in a pupil plane of the optical imaging system by a wavefront measurement method, determining focus offset measured values in an xy-direction and/or z-direction for one or more different illumination settings by a test pattern measurement method with imaging and comparative evaluation of test patterns for the optical imaging system, and determining values for one or more aberration parameters that relate to the distortion and/or image surface from a prescribed relationship between the determined wavefront aberrations and the determined focus offset measured values.

Abstract: A method for determining one or more process parameter settings of a photolithographic system is disclosed.

Abstract: An optical object distance simulation device is disclosed. The device has an optical lens module composed of a plurality of optical lens and the optical lens module is arranged between an optical lens and a chart for simulating the real object distance and reducing the space required for testing an optical lens. Moreover, the optical lens module is separated from a light-emitting element, a power supply or any heat-generating elements all separated from the optical lens module. Furthermore, the heat-dissipating elements are arranged near elements that generate substantial heat. Hence, not only does the present invention have a good heat-dissipating effect, but it also prevents external dust from polluting the optical lens module because of the positioning of the heat-dissipating element and the heat-dissipating hole.

Abstract: An error in a camera having angular velocity sensors is eliminated. A camera is placed on a rotating table and rotated, angular velocities are detected by angular velocity sensors, and a CZP chart is photographed. The motion of the camera is computed as a locus of motion of a point light source on an imaging plane from the outputs from the angular velocity sensors. The inclination of the locus motion is compared with the inclination of a zero-crossing line which has been obtained by subjecting the photographed image to Fourier transformation, to thus compute angles of relative inclination of the angular velocity sensors with respect to the image sensor.

Abstract: A method for determining one or more process parameter settings of a photolithographic system is disclosed.

Abstract: In accordance with one embodiment of the present invention, a method of characterizing a lens is provided. According to the method, an optical source such as a laser is configured to generate a collimated beam that is focused along an optical axis at a distance fext. A test lens is placed along the optical axis, wherein the test lens is characterized by an effective focal length fi that is substantially independent of incident irradiance. An output beam generated from the focused optical source and the test lens defines an output intensity profile at an observation plane located a distance Z0 from the focal point of the optical source. The on-axis intensity I of the output intensity profile along the optical axis at the observation plane is monitored as the placement of the test lens along the optical axis is varied. A z-scan signature of the test lens is generated from the monitored intensity I.

Abstract: The invention relates to an optical device in which a spherical aberration is detected. The optical device comprises means (206, 208) for focussing a first radiation beam (203) having a first numerical aperture and a second radiation beam (204) having a second numerical aperture lower than the first numerical aperture, on an information carrier (200). The optical device further comprises means (211) for detecting a first focus error signal corresponding to the first radiation beam and a second focus error signal corresponding to the second radiation beam. In order to measure the spherical aberration of the first radiation beam, due to a variation of the cover layer thickness of the information carrier, the optical device comprises means (212) for measuring a spherical aberration of the first radiation beam from the first and second focus error signals.

Abstract: An apparatus and method for automatically focusing a miniature digital camera module (MUT) is described. A MUT is loaded onto a test fixture and aligned with an optics system of a test handler. Focus targets contained within two target wheels are positioned over an optical centerline above the digital camera module using stepper motors. A field lens is positioned to focus an image of the targets onto the lens opening of the MUT. The image can be of a single target or a combination of targets contained on the target wheels at various optical distances from the MUT. A focusing unit adjusts the lens cap of the MUT for a best focus setting and after the MUT has been tested the best focus setting if physically fixed by permanently connecting the lens cap to the body of the MUT.

Abstract: A lens meter for measuring optical characteristics of a subject lens to be measured includes at least three light sources for measurement, a projecting lens which projects measurement light bundles from the light sources onto the subject lens placed on a projecting-lens optical axis, a diaphragm having an aperture disposed at an anterior focal point of the projecting lens between the light sources and the projecting lens, and a two-dimensional photodetector photo-receiving the light bundles passing through the subject lens after passing through the aperture of the diaphragm and the projecting lens without the use of an image forming optical system, and the projecting lens is disposed so that the light sources is conjugate with the photodetector in a case where the subject lens with a specific diopter in the vicinity of 0D or a frequently-used specific diopter is placed on the optical axis.

Abstract: An apparatus for measuring characteristics of a substance is provided. The apparatus includes a light source to generate light to form an image. A splitter transmits the light from the light source to a first lens, which collimates the light. A second lens receives the collimated light and is adapted to oscillate with respect to the substance and adapted to transmit and focus the light to a focal region within the substance, such that the oscillation will cause the focal region to pass back and forth through the substance and its surfaces/interfaces. A sensor receives light reflected from the focal region and provides a signal indicative of characteristics of the substance at the focal region.

Abstract: A focus error detecting device for an optical pickup having an aberration correcting lens group includes a diffraction optical element having an outer diameter which is smaller than a diameter of the light beam after aberration correction, and selectively diffracting light passing through an annular portion with an optical axis as a center in a plane perpendicular to the optical axis of the light beam; and a photodetector which detects the light diffracted by the diffraction optical element. The annular portion includes a portion in which residual ray aberration after aberration correction by the lens group is the smallest.

Abstract: A focal length measuring device comprises a light source unit for generating a collimated light, a diffraction grating for deflecting the collimated light by a deflection angle ?, and an image-pickup element for measuring a position of a focused spot light after the deflected light passes the lens to be tested. The diffracting grating is disposed near a front focal plane of the lens to be tested. The image-pickup element is disposed near a rear focal plane of the lens to be tested. A focal length is calculated according to a relationship such as h=f tan ? under condition that h indicates an image height as a distance from the optical axis. By doing this, it is possible to measure the focal length accurately and easily while restricting an influence of a depth of focus and an aberration.

Abstract: An apparatus controls positions of plural mirror segments in a segmented mirror with an edge sensor system and a controller. Current mirror segment edge sensor measurements and edge sensor reference measurements are compared with calculated edge sensor bias measurements representing a global radius of curvature. Accumulated prior actuator commands output from an edge sensor control unit are combined with an estimator matrix to form the edge sensor bias measurements. An optimal control matrix unit then accumulates the plurality of edge sensor error signals calculated by the summation unit and outputs the corresponding plurality of actuator commands. The plural mirror actuators respond to the actuator commands by moving respective positions of the mirror segments. A predetermined number of boundary conditions, corresponding to a plurality of hexagonal mirror locations, are removed to afford mathematical matrix calculation.

Abstract: Before measuring a wavefront aberration of a projection optical system, an image formation position of an image of a pattern of a test reticle which is formed on a predetermined surface is detected by an AF sensor. Based on a result of this detection, the position of an incident surface of a wavefront aberration measurement unit is adjusted, and a position of an image of the pattern with respect to the incident surface is adjusted. After this adjustment, the image of the pattern formed through the projection optical system is detected by the wavefront aberration measurement unit, and a wavefront aberration detection section is used to obtain wavefront aberration information of the projection optical system based on a result of this detection.

Abstract: An optical coupler 13, a reflection attenuation amount measurement photodetector 14, and an APC photodetector 15 are provided in a variable-wavelength light source apparatus 1 and the reflection attenuation amount can be measured simply by connecting a device under test without using any external optical power meter, etc, and when wavelength calibration is executed, an external wavelength calibration gas cell 18 and a total reflection termination 20 are connected, whereby the wavelength of an optical signal output from a variable-wavelength light source 11 can be measured and controlled with higher accuracy.

Abstract: There is disclosed aberration measuring method of a projection optical system comprising collectively irradiating the finite region of the photomask in which a diffraction grating is formed with the illuminating light emitted from secondary light source having point sources, projecting 0th-order and 1st-order diffracted lights to first and second measurement planes conjugated with the secondary light source by using a projection optical system, respectively, the 0th-order and 1st-order diffracted lights being passed through the photomask, measuring a relation of projected positions in the first and second measurement planes between the 0th-order diffracted light and 1st-order diffracted light of the light emitted from one arbitrary point source, respectively, obtaining lay aberration concerning the light emitted from the point source on the basis of the obtained two relations of projected positions.

Abstract: An enhanced dynamic range wavefront sensing system includes a light source disposed on a first side of an optically transmissive device, a wavefront sensor disposed on a second side of an optically transmissive device, a relay imaging system disposed between the optically transmissive device and the wavefront sensor, and means for adjusting a distance between the light source and the optically transmissive device. Beneficially, the relay imaging system includes a range-limiting aperture to insure that the wavefront sensor never goes out of range so that a feedback system can be employed to move the light source one focal length away from the optically transmissive device.

Abstract: In a cup attaching apparatus, a cup is attached as a processing jig to a subject lens along a reference axis, the lens and an index plate having an index of a predetermined pattern are illuminated by substantially parallel rays of light shaped into a diameter larger than a diameter of the lens so that an image of the lens and an image of the index are projected onto a screen, and the index image projected onto the screen is detected, whereas an entire image of the lens projected onto the screen is picked up. An optical center of the lens with respect to the reference axis is obtained on the basis of the index image detected by said detecting means, thereby displaying in a superposed manner alignment information indicating a relative position of the optical center with respect to the reference axis and the image thus picked up. The alignment is effected while observing the displayed information.

Abstract: A method for copying a recorded series of bits from a first location to a second location on a rewritable disc media. The method includes the steps of selectively marking a beginning point and an end point of a segment of the recorded series of bits, and a location to which said segment is to be copied prior tp said reading step. Subsequently, video data comprising at least a portion of the segment of the recorded series of bits to be copied is read from the disk and stored in a track buffer of a DVD device. At least part of the video data from the track buffer is subsequently transferred directly from the track buffer to the record buffer by a control processor of the DVD device. Finally, the portion of the video data stored in the track buffer is written to the second location.

Abstract: A method for evaluating the quality of a lens comprising illuminating imaging light on a screen through the lens to form a projected image, where the imaging light having a test-pattern image is generated using a test sheet on which a test pattern for measuring a resolution of the lens is formed to evaluate the resolution of the lens; detecting a brightness of the test-pattern image displayed on the screen by an image-capturing device using an imaging sensor; calculating an input level on the basis of the detected brightness of the test-pattern image; and calculating an evaluated value of resolution. The method, further comprises adjusting a position of the test sheet to a position corresponding to a focus of the lens by detecting the test-pattern image while moving the test sheet back and forth in the direction along an optical axis of the lens.

Abstract: A focal length measuring device comprises a light source unit for generating a collimated light, a diffraction grating for deflecting the collimated light by a deflection angle &thgr;, and an image-pickup element for measuring a position of a focused spot light after the deflected light passes the lens to be tested. The diffracting grating is disposed near a front focal plane of the lens to be tested. The image-pickup element is disposed near a rear focal plane of the lens to be tested. A focal length is calculated according to a relationship such as h=f tan &thgr; under condition that h indicates an image height as a distance from the optical axis. By doing this, it is possible to measure the focal length accurately and easily while restricting an influence of a depth of focus and an aberration.

Abstract: In laser machining a feature of a predetermined depth in an object, laser radiation is directed onto the object by an apparatus including an optical system. The optical system includes a movable lens element for varying the focal length of the optical system. Laser radiation reflected from the object is collected by the optical system and used to by the apparatus determine whether or not the laser radiation is focused on the object. The laser radiation is initially focused on the object. As the feature depth increases during machining the movable lens element is incrementally moved by the apparatus to refocus the laser radiation on the base of the feature. The instant depth of the feature is determined by the apparatus from the lens motion and compared with the predetermined depth. The apparatus terminates the machining operation when the instant depth determined from the lens motion is about equal to the predetermined depth.

Abstract: A device for detecting a wavefront that is defined by a plurality of contiguous light beams includes an array of lenslets for isolating the individual light beams and focusing each individual light beam to a focal point in an x-y plane. The device also has a plurality of clusters which are positioned in the x-y plane, and each cluster includes a plurality of pixels that are arranged in rows aligned in an x-direction, and columns aligned in a y-direction. Additionally, each pixel of a cluster includes both a first photocell for generating an x-signal and a second photocell for generating a y-signal, respectively, in response to an illumination of the pixel by a light beam. Further, the device includes circuitry for converting the x and y signals to digital signals and then using the digital signals to determine an x-y position for the focal point of the particular light beam that is incident on the cluster.

Abstract: A laser system is disclosed wherein a tunable laser signal has encoded within it information related to its wavelength at any instant in time. This encoding in one example is performed by modulating the signal to contain its wavelength information. This is particularly useful in a distributed system for testing optical components, wherein at a test site, the test station must determine the wavelength of light at which a component was tested.

Abstract: A method and system are provided for measuring a characteristic of a lens. By directing light to a lens, and receiving reflected light from a opposite end faces of the lens on an image plane, a determination from the focused spots on the image plane can be made as to a characteristic of the lens, such as its focal length.

Abstract: A wavefront sensor includes a plurality of lenses disposed in the same plane, and an area sensor that receives a bundle of rays of light collected through each of the lenses as a luminous point. Each of the lenses comprises a plurality of concentric areas with different focal lengths, and the area sensor is located substantially halfway between a first position in which a plane wave forms an image after passing through one of the concentric areas with a minimum focal length, and a second position in which the plane wave fronts an image after passing through another area with a medium focal length. With the wavefront sensor thus arranged, the measurement can be always achieved with high accuracy without involving noticeable blurring of luminous points on the area sensor regardless of the wavefront shape of a light beam indent to the lenses.

Abstract: A variable field angle and test patern spatial frequency optical assemblage 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: An improved apparatus and method for evaluation of focal length and transparency of vertebrate eye lenses is provided. Preferably with the aid of an alignment camera, a lens horizontally mounted in a transparent container is positioned with the axis of the lens aligned with scanning direction of a laser projected vertically through the lens. The laser is scanned across the lens, and an analysis camera at ninety degrees to the scanning path captures images of the path of the laser beam through the lens. The images are then analysed for determination of focal length, spherical aberration, and the like. Changes over time in response to a stimulus may be evaluated.

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: 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 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: 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.