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

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

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

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

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

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.

• 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:

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

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.

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.