for industrial applications · z‐axis spindle airbearing basic measuring functions the basic...

OEG GmbH, Wildbahn 8i, 15236 Frankfurt / Germany www.oeggmbh.com [email protected]

OTS Micro for high accurate measurement of small specimen

OTS 200 Standard setup

for industrial applications

General Description Optics Test Stations from OEG are proven solutions for lens testing. They are worldwide used for the measurement of optical parameters of single lenses and optical systems. OEG has introduced a unique concept to prove the outstanding measuring accuracy of its equipment. Optics Test Stations from OEG work software controlled and motorized. The data acquisition is performed electronically with highest accuracy. OTS guarantees user‐independent measuring results. The OTS systems are useful as well in series testing as for single measurements in laboratories. The setup is modular and can be upgraded on demand with additional measuring functions. The OTS Optics Test Stations provide the following measuring functions for spherical optics: ‐ Effective Focal Length (EFL) ‐ Back Focal Length (BFL) ‐ Radius of Curvature (R) ‐ Flange Focal Length (FFL) ‐ Modulation Transfer function (MTF) ‐ Centering ‐ Twist of cylindrical lenses ‐ Symmetry of cylindrical lenses ‐ Wedge angle of cylindrical lenses The OTS is extendable to the measurement of plano optics. There are only some additional mechanical mountings and a software module necessary. This allows the measurement of wedge angle / parallelism of windows or filters or the 90° angle of prisms. If you have any doubt, if the equipment meets your needs, please contact us. There are many functions available.

General setup The optical‐mechanical main components of the OTS are: ‐ the basic frame with integrated measuring collimator; ‐ the motorized, software controlled reticle changer; ‐ the measuring head consisting of electronic autocollimator with attachment objectives; ‐ the motorized, software controlled z‐axis for high accurate positioning of the measuring head.


OTS 500 Set of measuring

OTS 200 self centering holder

OTS 500 Setup for EFL measurement

The autocollimator of the measuring head can be used depending upon measuring function in autocollimation or as telescope (then in connection with the measuring collimator). The illumination units are equipped with an electronic brightness control, in order to make an adjustment possible to the reflection characteristics of the test specimen (by use in autocollimation) or the free aperture

of lens under test (measurements in transmission). The illumination wavelength can be adapted to special demands. The accurate motorized z‐axis has a positioning resolution of 1 µm and a positioning accuracy of 5µm. Thus the exact detection of the image plane position is ensured. The subjective influence of the measurement results is avoided by the autofocus function. Except of the centering error measurement, the specimen holder consists of a self‐centering holder with a diameter range up to 100 mm, very common in optical industry.

OTS types Basically there are 2 different standard types exist: OTS 200 and OTS 500. The main differences are described in the table:

OTS 200 OTS 500

EFL of measuring collimator 200 mm 500 mm

Free aperture of measuring collimator 28 mm 65 mm

measuring ranges for EFL, BFL, FFL, Radius +/‐ 600 mm +/‐ 1200 mm

z‐axis spindle airbearing

Basic Measuring functions The basic system contains the measuring functions Focal length (EFL), Back focal length (BFL), Flange focal length (FFL) and Radius (R). The measuring principles are very common in the optical industry. But because of the electronic data acquisition and evaluation and the autofocus function it provides a very high accuracy and reliability. For detailed information about the measuring principles please refer to the user manual. Because the measurements are software controlled, the OTS operation is very easy. Of course, the software runs under current operation systems and meets the expectations of each user in optical industry. For single measurements, the stage can be controlled by joystick.


Centering module ‐ to be mounted on OTS

OTS 200 Setup for MTF measurement

OTS 200 Setup for measurement of plano optics

Centering measurement For the centering measurement an additional mechanical module is necessary. This module must be mounted on the specimen table instead of the self‐centering holder. The lens under test is mounted on a ring edge and pressed against a V‐stop. A set of ring edges and V‐stops is supplied as

standard. Additional ring edges and V‐stops might be necessary, depending on the size of the lens under test. The lens under test is rotated by a friction wheel, which is pressed manually against the lens. The V‐stops are adjustable in 3 axes, so that it fits to all specimen sizes. Also the friction wheel position can be adjusted to the size of the specimen. During the rotation of the specimen, the centering is measured in transmission or in reflection. Additionally necessary for the operation is vacuum, ‐0.6 bar at least. The picture shows the centering module to be mounted on the OTS for centering measurement.

MTF measurement

One optional module of OTS is the MTF measurement. The MTF can be measured on‐axis tangential and sagital. Additionally the line‐ and edge spread function and the grey scale distribution can be measured. For MTF measurement, a special measuring objective is provided together with the according software.

Measurement of plano optics Plano optical elements can be measured with OTS. For this function, no measuring objective is necessary. Without measuring objective the OTS works like collimator‐telescope or only autocollimator setup. A reference measurement is made without specimen. After the reference measurement, the specimen is positioned in the measuring beam. The deflection is measured.


OTS‐Z for cylindrical optics

OHM 150 Optical Height Gauge e.g. for camera chip adjustment

Collimator for special application

Measurement of cylindrical optics The optics test station OTS can be used for the measurement of cylindrical optics. For big cylindrical lenses it can be equipped with a x/y‐stage. Beside the standard measuring functions (EFL, BFL/FFL, Radius and MTF) there are the following additional measuring functions available: 1. Symmetry (offset) measurement The Symmetry describes the displacement of the optical axis to the mechanical symmetry axes of a cylinder lens. 2. Twist measurement The twist describes the angular displacement of the cylindrical axes relative to a mechanical reference edge of a cylinder lens. 3. Wedge angle measurement The wedge angle describes the angle between the plane surface and the vertex surface line of the cylinder lens.

Special solutions for testing of optics and cameras On the basis of our standard equipment we are able to develop special solutions in short time and for affordable prices. The picture on the right shows a special system for the high accurate adjustment of CCD chips in industry cameras (special product information available). This system is also suitable for contactless measurement of FFL, Radius and height of objects. Other solutions, already realized for several customers, are the measurement of camera MTF or special adjustment benches for sensors by the MTF criteria. Of course, specialized MTF benches like MTF VARIANT or MTF MASTER belong to our standard equipment range. For this products are special informations available. Please contact us for detailed OTS product information or quotations!

for industrial applications · z‐axis spindle airbearing basic measuring functions the basic...

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