Optical profiler with diamond turning machine optimisation

Zygo Corporation announces the release of Compass 2, its latest optical profiler with Diamond Turning Machine (DTM) optimisation and freeform surface metrology capability. Unlike comparable solutions, mould pins remain on their manufacturing fixture during metrology―shortening the time to data processing and minimising uncertainty from remounting and re-aligning the sample.

With new interface improvements, the Compass 2 now delivers 3x better form deviation performance than the original Compass.  

Eric Felkel, Product Manager at ZYGO says: “The Compass 2 is designed for the analysis of rotationally symmetric spherical and aspheric, geometrically truncated, and freeform surfaces. It can measure both discrete lenses and injection moulding pins; and the instrument has been specifically tailored to meet the needs of manufacturers using this process with a series of new capabilities.

“Beyond just DTM integration, the Compass 2 has the necessary XYZ precision to report nm-level roughness data that includes automatic generation of high-frequency texture and tooling mark surface maps.  A unique feature is the ability to click at a point on a data map and the system quickly navigates to that specific location on the sample for a more detailed inspection.”

Diamond Turning Machine (DTM) tool path correction support: The data obtained by the Compass 2 can now be directly used to optimise a DTM toolpath by automatically exporting 3D prescription deviation data for use with multiple DTM platforms as well as multi-platform software such as DIFFSYS.

Compass 2 supports DTM Tool setup with tool offset and tool radius measurement for spheres and aspheres and can report predicted surface deviation after offset and radius correction.

The new Compass 2 sample interface includes a standard vacuum chuck fixture that supports DTM chuck/jigs with a diameter between 10-155 mm and weight up to 0.8 kg. Mould pins can remain on their manufacturing fixture during metrology, shortening the time to data and minimising uncertainty from remounting and re-aligning the sample―particularly when conducting measurements for tool path correction.

Freeform support: As the designs for mobile device cameras evolve, freeform surfaces are being increasingly used. Freeforms are designed with little or no symmetry, which makes them challenging to measure for most metrology instruments.  Compass 2 now includes both freeform and truncated surface analysis in its software package. Compass 2 uses its ability to track a surface during measurement to capture the freeform surface. The platform will compute the deviation of that tracked surface to the optical prescription of the freeform in the same way as traditional aspheres over a full 3D measurement area.

A completely new platform: Compass 2 has been designed from the ground up with an emphasis on robust metrology and high confidence. This plays to the use of highly accurate metrology tools in-process rather than in-lab, and often working in extremely dynamic and challenging areas on the factory floor.  Improvements include new:

* Isolation platform with 10x better seismic isolation

* Highly optimised support structure

* Enclosure and user station are fully decoupled from the instrument

* Separated electronics rack isolates noise sources away from the metrology

The enclosure and equipment rack also allows easier installation, easier servicing, easier measurement part access, and reduced vibration and turbulence at the machine. 

Legacy metrology tools can be challenged with measuring larger slope angles, can be time-consuming, have a small measurement range, and have a small working distance. The Compass 2 addresses these challenges by using optimised non-contact, three-dimensional coherence scanning interferometry with field stitching―making it the platform of choice for system-critical micro-optical surfaces.