Metrology

We measure, what we manufacture.

We make use of extensive measurement techniques and develop individual measurement setups in order to ensure that our optical components, assemblies and systems comply with your specifications. We create own software to measure customer-specific parameters.

Information about the various methods for material analysis and service life tests can be found under the section Material Analysis.

Selected Measurement Technologies

Wavefront Measurements

We employ various highly precise interferometers (up to λ/20 WF PV) to characterize the flatness of optical surfaces as well as wavefront deformations in reflection and transmission. We possess many years of experience in optimally adapting measurement tools and processes to your product. For example, we can conduct measurements in vertical or horizontal testing configurations or take measurements in a clean room or vacuum. Optical surfaces undergo testing using in-house interferometers during the manufacturing process.

Phase shifting Fizeau interferometers for large planar surfaces up to 24 inches
Interferometers with short coherence length for multiple-layered glass
Interferometers CGH wavefront formation for cylindrical surfaces up to 100 mm; stitching along apex line up to 2,000 mm; radii of 4 mm to infinity
Stitching interferometer
Stitching interferometer for aspherical lenses
Infrared interferometer, 3.4 µm
Shack-Hartmann wavefront sensors for wavelengths of 350 nm to 1,064 nm and beam diameters up to 15 mm


Interferometer measuring facilities at Berliner Glas (selection)

Measurement example of Zerodur flat test piece 305x115 mm²

Dimensional, Shape and Layer Measurements

Tactile 3D-coordinate measuring machines

Touch and scanning systems
Measurement volume up to (9x20x8) dm³
Permitted length measurement deviation of MPE E pursuant to DIN EN ISO 10360-2 between 0.6 µm + L/600 and 3.0 µm + L/250

Leitz PMM-C 700

measuring sensor configuration - sample picture at Berliner Glas site

Measurement button configuration

Optical coordinate measuring machines

Some multisensor devices with touch buttons
Measurement volumes up to (6.5x7.5x5) dm³
Structure resolution up to 1 µm
Permitted length measurement deviation of E 2D (OT) pursuant to VDI/VDE 2617 Page 6.1 between 1.5 µm + L/250 and 2.8 µm + L/125
Touchless measurement of the absolute position of optic surfaces in multiple-lens systems, accuracy < 1µm

OGP Smartscope Vantage machine at Berliner Glas site

OGP Smartscope Vantage 650

Angle Measurement of Optical Components

We use a goniometer with an accuracy of 15 µrad to measure flat and wedge plates, prisms and polygons.

Micro-Roughness

Structure on CrN

White light interferometer

Vertical resolution up to ca. 0.1 nm
(for Ra < 10 nm)
Lateral resolution up to 0.64 µm
NA up to 0.55
Picture fields up to (7.07x5.30 mm)
Stitching algorithms
Record objects up to 800 mm in edge length

Spectral Reflection and Transmission Measurement

We use the spectral reflection and transmission measurement process to consistently control and monitor our high quality standards. To measure the material properties of spectral transparency and spectral reflectivity, we employ the Perkin-Elmer Lambda 19, Lambda 900 and Lambda 950 devices.

Schematic diagram of reflection measurement

Schematic diagram of transmission measurement

(Cylinder Lens) Centering

Lens and objective testing device
Centering measurement of individual lenses and lens systems

The measurement accuracy of up to 50 µrad depends on the lens geometry.

Cylinder lens centering
Measurement uncertainties (accuracy) when determining the three centering errors of cylinder lenses:

Displacement of the apex line	4 µm
Contortion of the apex line	25 µrad (at 100 mm lens length)
Wedge error of the lens	16 µrad

An overview of the various cylindrical lenses that we offer at Berliner Glas can be found on the page Cylinder Optics.

Imaging Performance

MTF measuring system

Modulation Transfer Function (MTF)

A large MTF system with a maximum aperture of 200 mm is available to measure imaging quality. In addition to MTF measurement, further characteristics like distortion, field of curvature and focal width for field angles > 90° can be measured. Object and image positions are finitely and infinitely adjustable in wide areas.

Measurement Technology Design

For special demands not included in our standard processes, we develop customer- and application-specific testing areas that allow automatic evaluation using specially adapted software. Our testing processes are the result of close cooperation with the optical design experts and consider the possibility of actively adjusting optical elements in order to guarantee optimum product quality.

Das versetzt uns in die Lage, physikalisch mögliche Leistungsgrenzen zu erreichen und die optimale Qualität Ihrer Produkte zu gewährleisten.

This allows us to achieve the performance limits that are physically possible

Depending on the product and needs at hand, the performance limits physically possible are met and maintained in many cases.