OPTOMATICFully Automatic Optical Bench

DESCRIPTION

MEASUREMENT PRINCIPLE

Effective Focal Length

A highly corrected collimator projects the ima-ge of a special target to infinity. The parallelray bundles enter the lens under test parallelto the optical axis and emerge from the lensas a convergent beam intersecting in the fo-cal plane.The target image formed in the focal plane ofthe lens under test is collected by a microsco-pe assembly and focussed on the high resoluti-on CCD array accurately located in the focalplane of the microscope.The microscope assembly with the CCD arrayis mounted on a motorised linear stage drivenby a stepper motor.A computer-controlled Auto-Focus System al-lows for automated and accurate finding ofthe focal plane of the lens under test. Simulta-neously the size of the projected collimatortarget is precisely determined and thus the ef-fective focal length (EFL) of the lens under test.

All aspects of the data acquisition starting withthe powerful Auto-Focus System, scanning ofthe CCD array, self-calibrating and displayingthe measured data are under software controland fully automated. The set up and measure-ment parameters for one lens type can be sto-red to a file and loaded again when neces-sary. This reduces considerably the set up time,so that an operator measuring a new batch oflenses starts producing reliable measuring da-ta in 5-10 seconds.

DESCRIPTION

OPTOMATIC is the first fully automated opticaltest instrument featuring rapid, ultra-accurateand objective performance characterizationof a wide variety of optical components andlens systems.

Responding to customer requirements for in-creased speed and accuracy in measure-ment of optical parameters, OPTOMATIC pro-vides dramatically increased overall accuracyand software control of the complete measu-ring procedure.

Almost all optical parameters of lenses withdiameters from 0.5mm to 200mm can be auto-matically measured: effective focal length,back focal length, flange focal distance, cen-

tration errors in transmission and reflection,angle and power of wedges, MTF, etc.The operation is simple: once the test parame-ters for one lens are defined, these can be sa-ved to a set up file and used for further measu-rements. The measured data are accurateand repeatable. The software package designed to work un-der all Windows operating systems providesmenu-driven operator guidance and advan-ced data management.

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OPTOMATICFully Automatic Optical Bench

Microscope assemblywith CCD array

Travel of linear stage

VideoProcessing

Target generator withcollimating optics

Reticle withcalibrated target, y

Sample

Flange Focal Length

The Flange Focal Length (FFL) or the FlangeFocal Distance (FFD) is the distance betweenthe locating surface of the lens mount and theimage plane. This parameter is especially im-portant for the photographic lenses as di-stance between the locating surface of thelens mount and the film (image) plane.

The self-centering sample holder of the OPTO-MATIC has three stable pins with a diameterstep providing a precise mechanical stop forthe lens mounts. The pins are made of harde-ned and grinded steel to ensure the necessarystability. The locating surface of the lens mountmust be in ferm contact with the pin step asmecanical stop. To determine the position ofthe mechanical stop and thus of the locatingsurface of the lens mount, a special reticle inmount is positioned into the sample holder.The optical head of the OPTOMATIC will auto-matically focus and accurately ascertain theposition of the the illuminated special reticle.

Since the thickness of the reticle mount (di-mension X) is accurately measured before, theposition of the mechanical stop is easily calcu-lated. After this, the serial measurement of FFLcan start: the image plane of the sample ismeasured and the FFL is automatically calcu-lated and displayed.

Besides the absolute measurement of FFL a re-lative measurement is also possible. In this ca-se a master lens is measured as a reference.The data are stored and then compared withthe results of the serial measurement.

Back Focal Length

The Back Focal Length (BFL) is the distancefrom the vertex of the lens to the second focalpoint. The optical head for BFL-measurement is

designed as a special autocollimating deviceincorporating a special target, beamsplitterand imaging optics. A fiber optic illuminationwith condenser optics illuminates the target.The projected image of the target is automati-cally focussed on the vertex and in a secondstep in the focal plane of the lens under test.

Each position of the two focussing planes (lensvertex and focal plane of the lens) is accura-tely measured. The distance between the twofocussing positions is the BFL.The collimated beam for the focal plane mea-surement is provided either by a tilt mirror loca-ted behind the lens under test or by the colli-mator included in the optical set up of theOPTOMATIC. When using the standard collima-tor, a second illumination unit with a shutter isneeded. Each illumination unit is active whenthe corresponding focussing (on to the vertexor in focal point) is accomplished.

MEASUREMENT PRINCIPLE

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BFL-Measurement with OPTOMATIC

Set up for FFL-Measurement

Set up for BFL-Measurement

Special reticlein mount

Iluminationassembly mounted on sample holder

Sample HolderOptical Head

Optical Head

BFL

Focussing on Lens Vertex

Tilt mirror mount

Focussing in theImage plane

Reference plane Mechanical stop

Sample Holder

lens is positioned in a precision self-centeringholder featuring four indexing stops at 90°androtation over 360°. During the holder rotation, measurement dataare taken in any of the indexing stop positions.A special alghoritm allows for automatic calcu-lation and display of the centering errors. Theresult of the measurement can be given as ra-dius of the run out circle (in µm) with an accu-racy of +/-0.5µm or as tilt of the surface or ofthe lens axis (in arcsec).

MTF-Measurement

The set up for MTF measurement includes thestandard optical head equiped with a high re-solution relay lens. A narrow bandwidth interfe-rence filter is mounted into the illumination unitof the collimator. Two basic measurement procedures are avai-lable: MTF-calculation based on the evaluationof the image of an edge target and a secondprocedure based on the analysis of the imageof a slit target.The edge image evaluation can be carried outwith the standard collimator target i.e. adouble slit, which is primarily used for EFL mea-surement. The advantage is the simplicity of theequipment and the simultaneous measurementof EFL and MTF.

Centration Errors

The normal procedure to identify the centeringerrors is to rotate the sample in transmitted or

reflected light. For the measurement in Trans-mission the standard optical head and the colli-mator is needed. The parallel beam emergingfrom the collimator is focussed in the focal pla-

ne of the sample tobe measured.

For centration measu-rement in Reflection,the autocollimatingoptical head (sameused for BFL measure-ment) is mounted onthe measuring unit in-stead of the standardoptical head. The Au-tocollimating OpticalHead is focussing in

the center of curvatureof the lens.When rotating the lensunder test - if centeringerrors are present - theimage of the target for-med on the CCD willmove correspondingly.The size of the displace-ment is proportional withthe centering error. In or-der to be rotated, the

MEASUREMENT PRINCIPLE

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Measurement of centering errors in Transmission Modewith OPTOMATIC

Measurement of centering errors in Reflection Mode withOPTOMATIC MICRO

Standard Optical Head

Ultra-precisionRotary Holder

Measuring Centration inTransmission Mode

AutocollimatingOptical Head

Ultra-precisionRotary Holder

Measuring Centrationin Reflection Mode

However, due to the measuring principle theaccuracy is limited. This procedure is very costeffective and recommended for productionquantities when relative measurements incomparison with a master are acceptable.The slit evaluation requires a special slit targetto be mounted in the collimator. The MTF cal-culated from the slit evaluation is more accu-rate, however, it requires expensive hardware.The OPTOMATIC system includes a special illu-mination unit with an electronic shutter. The el-ectronic shutter is software controlled andopens alternatively the double slit for EFL mea-surement or the narrow slit for MTF-measure-ment.

Angle and Power of Wedges

The unique versatility of OPTOMATIC is underli-ned by the capability to measure not only pa-rameters of lens systems but angles and powerof wedges, windows, plane-parallel plates.A li-mited types of prisms (pentaprisms, 180°-prisms) can be measured as well.

The set up includes an ancillary lens positionedin the sample holder. A reference measure-ment of this lens is taken. The position of the fo-cal plane of the ancillary lens and the position

of the target image on the CCD is accuratelydetermined and saved. Placing a wedge bet-ween the collimator and the ancillary lenscauses a displacement of the target image onthe linear CCD array. The displacement ismeasured and the deviation angle calculatedand displayed with a resolution better than 1arcsec. over a range of 1°-1.5°.

Aberrations of the transmitted wave frontthrough the wedge or window under test will re-sult in modifications of the EFL of the ancillarylens. Thus the power of wedges and prisms canbe simultaneously determined with an accu-racy better 0.002 dpt.

WIDESPREAD APPLICATIONS

OPTOMATIC has been design to measure a wi-de range of optical parameters related to al-most all typical optical components and lenssystems.Virtually any existing lens systems ranging fromhigh performance photographic lenses andmicroscope objectives to endoscope, ophtal-mic lenses, singlets and doublets or moldedplastic lenses can be accurately measured. Further applications include the measurement of:

• high performance lenses• cinematic and TV lenses• enlarger and projection lenses• copier and scanner lenses• microlenses for CD and DVD applications

The capability to measure simultaneously theEFL and centration errors makes the OPTOMA-TIC an ideal measuring station for industrialand medical endoscope lenses.A special application is the measurement ofIntra Ocular Lenses. A dedicated version ofOPTOMATIC MICRO measures fast and accu-rately the power, the MTF and the astigmatismof IOL’s according to ISO 11979.

Not only high performance lenses can be ac-curately measured. Lenses with poor imagequality (ex.:plastic lenses for proximity switches,aspheric molded lenses, molded condenseroptics,etc) which can not be checked with vi-sual instruments are measured fast and relia-ble with OPTOMATIC.

APPLICATIONS

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Centration and MTF Measurement with OPTOMATIC MICRO

• selection of rapid or accurate measurementroutines offers highest operation flexibility

• to increase the efficiency in production pro-cess, the software has capabilities to savethe optimized process parameter for future use.

• for production use the main functions canbe transferred to a dedicated keyboard sothat even unskilled operators can provide re-liable measurement results.

Since all the software modules used for mea-surement of different optical parameters areintegrated into a main software program, thetime necessary to change to another applica-tion is minimal. The measurement certificate in-cludes besides the measurement data a stati-stical evaluation of the results.

Since OPTOMATIC has a modular design, spe-cific custom applications can be easily reali-sed by adding optional modules. In this way ispossible to meet different customer require-ments as testing of lenses with rectangular sha-pe or to extend the measurement capabilitiesin the NIR spectral range.

SOFTWARE

The advanced software is designed to workunder Windows operating systems and fulfilsthe need of the optical shop for easy, intuitiveoperation and features a large number of op-tions to accomodate a large variety of speci-fic requirements:

• selection of different measurement routinesfor samples with different imaging quality. Inthis way even samples with lowest imagingperformance can be easily tested.

SOFTWARE

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Measuring EFL and Centration Errors

INSTRUMENT SELECTION

The OPTOMATIC equipment line includes:

• OPTOMATIC - a versatile, horizontally set upinstrument which is recommended when a lar-ge variety of samples should be tested andwhen flexibility and quickly changing measu-rement tasks are required.

OPTOMATIC is also the prefered instrument formeasurement of longer focal length. However,due to the horizontal set-up the OPTOMATIC isless suited for centration measurement.

SOFTWARE

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Measuring diopter power and MTF of IOL

• OPTOMATIC 2000 - is vertically set up andspecially designed for measurement of lensesof large diameter (up to 200 mm). Due to the

large aperture collimator with longer focallength OPTOMATIC 2000 is also the right choi-ce for MTF measurement. All the basic modelscan be supplied in standard or customizedversions to fulfill special requirements.

• OPTOMATIC MICRO - is vertically set-up anddedicated to the measurement of small lensesand shorter focal lengths.

OPTOMATIC MICRO is recommended fortesting of mass production quantities of IOL’s orendoscopes lenses and for applications wherecentration measurement is main task (due tothe vertical set up).

INSTRUMENT SELECTION

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OPTOMATIC

OPTOMATIC MICRO OPTOMATIC 2000

ORDERING INFORMATION

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resolution CCD array, precision microscopeobjective or highly corrected achromats in or-der to accomodate to different samples anddifferent optical parameters.Moreover the software automatically adaptsto different requirements when measuring un-der extreme conditions as too small or verylong focal lengths, uncorrected lenses (poorimage quality), poor contrast, etc.

ORDERING INFORMATION

TECHNICAL SPECIFICATION

Considerations about accuracy

OPTOMATIC has been designed to cover a lar-ge measuring range and in this way to beco-me a universal measuring tool. To enable thiswithout sacrificing the accuracy, OPTOMATICuses selected hardware components like high

Description

OPTOMATIC 2000

2-300-00

2-300-01

2-300-08

2-300-11

2-300-05

2-300-07

2-300-03

2-300-06

2-300-16

OPTOMATICMICRO

2-200-00

2-200-01

2-200-12

2-200-08

2-200-11

2-200-05

2-200-07

2-200-03

2-200-06

2-200-16

OPTOMATIC

2-100-00

2-100-01

2-100-12

2-100-08

2-100-11

2-100-05

2-100-07

2-100-03

2- 100-06

2-100-16

BASIC INSTRUMENT

• Stand • Linear stage, stepper motor, stepper motor controller• Measuring head with high resolution linear CCD-array• High performance imaging head lenses• Image processing card for IBM-compatible PC• Target generator with collimating optics• Mount with self-centering holder. • Fiber optic illumination with long life cold light

source 150W• Software for positive focal length (EFL+)• Aluminium case for storage and transportation

• Extension for measuring negative focal length (EFL-)

• Extension of measuring range for positive / negativefocal length

• Option for measurement of back focal length(BFL+/BFL-)

• Option for measuring flange focal length (FFL+/FFL-)

• Option for measurement of centering errors in trans-mission

• Option for measurement of centering errors in reflection

• Option for angle measurement and power of wed-ges, plan-paralell plates and 180°-prisms

• Option for MTF-Measurement on-axis in tangential plane. Edge evaluation

• Option for MTF-Measurement on-axis in tangential plane. Special reticle pattern featuring a single slit/double slit. Electronic shutter. Slit evaluation

CODE

TECHNICAL SPECIFICATION

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The software also increases more than 20 timesthe resolution of the CCD, so that the measu-rement of the target image is made with a re-solution smaller than 1µm.

The unavoidable inaccuracies of the systemcomponents are eliminated through individualcalibration using high precision master lenscertified by different national standard institu-tes. This sofisticated and costly calibration pro-cedure assures the highest absolute accuracyof each instrument. The calibration values arestored in a special file and automatically usedto correct the raw measurement data. The dis-played measurement results are always cor-rected by means of calibration values specificto each instrument. The sofisticated calibrationprocedure is paying off in superior performan-ce as well in increased repeatability.

On request Master lens calibrated by nationalstandard institutes are supplied to customersfor in-house checking of the calibration of theinstrument or to be used when certificationaccording ISO 9000 is required.

Features

• Fully automatic and computer controlled measuring process

• Menu driven software• Calibration directly traceable to internatio-

nal standards• Extremely short measurement time• Advanced software running under all

WINDOWS® operation systems

Technical Data

OPTOMATIC 2000

+5…+1000 mm- 5…- 1000 mm

5 - 75 (200) mm

OPTOMATIC MICRO

+1...+150 mm- 2...- 150 mm

+150…+500 mm- 150…- 500 mm

1 - 35 (75) mm

OPTOMATIC

+5...+750 mm- 5...- 550 mm

+750…+1200 mm- 550…- 1200 mm

5 - 75 (100) mm

Effective Focal Length (EFL+/EFL-)

Standard measuring range:

Extension of measuring range

Lens Diameter

Repeatability

Measurement Accuracy

Measurement Time

0.03…0.2%

5...25 mm: 0.1%... 0.3%25…500 mm: 0.03%…0.1%

500...800 mm: 0.05%…0.1%800...1200 mm: 0.1%… 0.3%

First measurement: 5 - 8 secNext measurement: 3 - 5 sec

+5…+500 mm- 5…- 500 mm

5 - 75 (200) mm

+5...+150 mm- 5...- 150 mm

1 - 35 (75) mm

+5...+500 mm- 5...- 500 mm

5 - 75 (100) mm

Flange Focal Length(FFL+/FFL-)

Measuring range:(Extension on request)

Lens Diameter

Repeatability

Measurement Accuracy

Measurement Time

0.03…0.1%

0.05%…0,2%

First measurement: 5 - 8 secNext measurement: 3 - 5 sec

TECHNICAL SPECIFICATION

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+5…+450 mm- 5…- 450 mm

+5...+150 mm- 5...- 150 mm

+5...+500 mm- 5...- 500 mm

Centering Errors in Transmission and Reflection

Measurement Range (Extension on request)

Repeatability

Accuracy

Measurement Time

±0,5 µm or ±2 arcsec

±1 µm or ±5 arcsec

5-15 Sec

Angle and power of wedges and plan-paralell plates

Measurement Range

Accuracy

Power (optical effect)

Measurement Time

approx. 1°

±1 arcsec

± 0.002 dpt

1 sec

5...150 mm (EFL)5-500 mm (EFL)

1...75 mm (EFL)5-250 mm (EFL)

5...75 mm (EFL)5-500 mm (EFL)

MTF-Measurement on-axis in tangential plane

Measurement Range • absolute measurement:• relative measurement:

Test mode

Spatial frequency

MTF-Measurement / Edge evaluation• Repeatability• Accuracy

MTF-Measurement / slit evaluation• Repeatability• Accuracy

automatic. on-axis

0-150 lp/mm

2 %3 %

1 %2 %

OPTOMATIC 2000

+5…+450 mm- 5…- 450 mm

OPTOMATIC MICRO

+5...+150 mm- 5...- 150 mm

OPTOMATIC

+5...+500 mm- 5...- 500 mm

Back Focal Length(BFL+/BFL-)

Measuring range:(Extension on request)

Repeatability

Accuracy

Measurement Time

0.1…0.3%

0.2%…0,5%

10 - 25 sec

Dimensions and Weights

Trioptics GmbH . Optische InstrumenteHafenstr. 39 . D-22880 Wedel . GermanyTel: +49-4103-17461 . Fax: +49-4103-17363

e-mail: info@trioptics.comhttp://www.trioptics.com

1388 Crittenden RoadRochester, NY 14623-2308 U.S.A.

Tel. (716) 473-6540 . Fax (716) 475-1971e-mail: mildex@eznet.net

Home page: http://www.mildex.com

US Distributor:

Optical Workstation

OPTOMATIC is modular and upgradeable toallow for custom configuration as test require-ments change. All components of the instru-ment are individually calibrated. The calibrati-on values are stored in a special file and auto-matically used to correct the measured va-lues.This sofisticated calibration procedure ispaying off in superior product performanceand increased repeatability.Being an automatic turnkey system OPTOMA-TIC is not operator-dependent. This not only re-duce measurement time to a few seconds,but increases accuracy and reliability of thetest. The measuring results can can be printedout or saved to file.

Weight(Kg)

20

25

40

Length X Width/Depth XHeight (mm)

1250 X 200 X 300

280 X 400 X 800

350 X 600 X 1150

OPTOMATIC

OPTOMATICMICRO

OPTOMATIC2000

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