Subaperture stitching allows you to measure a broader range of parts including: bigger clear and numerical aperture surfaces, aspheric surfaces, and system tests.

QED's metrology also helps you to achieve better measurements: have greater confidence in the accuracy, resolution and diagnostics of your measurements to improve your productivity with automation and convenience features The bottom line... QED's subaperture stitching technology produces better measurements on a broader range of parts than any other measurement system.

QED's line of metrology products now includes:

• the SSI-A: measure optical surfaces up to and exceeding 200mm in diameter, including aspheres with up to 200 waves of departure;
• the ASI for full aperture measurements on parts up to and exceeding 200mm in diameter, including aspheres with up to 1000 waves (650 microns) of departure from best fit sphere, and,
• the MFA-400 which allows customers to capture mid-spatial frequency surface roughness on parts up to 400 mm.

FINALLY: AFFORDABLE FULL APERTURE METROLOGY FOR LARGE AND CONVEX OPTICS IS AVAILABLE.

Even today, optics manufacturers and their customers struggle to cope with serious limitations in conventional interferometry. Our industry is hampered by metrology systems that measure only a subset of all of the optics produced (typically 60-70%). The remaining 30-40% are either too large or too steep to be viewed over the full aperture accurately and affordably. QED's SSI-A makes it possible to measure almost any plano, convex, or concave surface up to and exceeding 200mm in diameter, without expensive investments in large-aperture systems or sophisticated transmission spheres. You no longer need to be satisfied with anything less than absolute, full aperture metrology for all of your optics.

ADDED FLEXIBILITY MEANS GREATER VALUE.

The SSI-A takes a standard 4 or 6 inch interferometer, expands its capabilities, and makes it easier to obtain accurate measurements. The SSI-A overcomes the insufficient coverage of 4 or 6-inch interferometers for convex and large plano surfaces by providing stitched, full-aperture data with higher absolute accuracy. In addition, for manufacturers that want to reduce cycle times and costs, the SSI-A provides rapid and accurate radius of curvature measurements, minimizing the dependence on traditional test plates and radius benches. The SSI-A can also be used to acquire higher data density across the full aperture of the part due to its increased lateral resolution.

SSI-A'S ABSOLUTE METROLOGY OFFERS BETTER QUALITY DATA AND SETS A HIGHER STANDARD.

While reference optics are commonly accepted as the "test standard”, they are inherently imperfect. From a practical standpoint, reference subtraction can remove these imperfections from the measurement, however, it is typically a difficult, and time-consuming process, requiring greater operator skill. Instead, the result of a typical interferometric measurement is an approximation that includes some reference wave error that is uncharacterized. The SSI-A overcomes this challenge and provides absolute metrology by checking the quality of every reference optic and subtracting the error automatically in the final result. Errors of machine motion and geometric distortion are also calculated and accounted for automatically when measuring every surface. After each measurement, a full report is generated, including a full aperture map, the computed reference optic error, and an estimate of the quality of the measurement.

SSI IS HIGHLY AUTOMATED AND EASY TO USE.

Like all of QED's systems, it is easy to become proficient at operating the SSI-A. Simply put, the operator need only define the surface to be tested and locate fringes at the center of the lens. The SSI-A Metrology System does the rest-automatically. It defines the lattice, moves to each lattice position, autonulls, acquires the subaperture data, stitches a full-aperture map and provides a detailed report that can be used to quantify the performance of the tested surface or even drive a subaperture finishing tool.