The OpTest® Bench: A Lens Metrology Multitool For The Defense Industry

Lens assemblies used for defense applications cover an incredibly broad range of values for design parameters like size, Field of View (FOV), spectrum, etc. They are also often designed around complicated requirements like low SWaP, ruggedization, and large operating temperature ranges. If you are a defense contractor or a lens supplier for a defense application, having the metrology equipment to characterize lenses across all of those requirements is key for optimizing your assembly processes, improving your production yield, delivering on your contract commitments, and keeping your customer happy with fielded units that work no matter what.

The OpTest Bench metrology platform was designed specifically for the broad range of testing requirements listed above, making it a powerful tool for our customers in the defense industry. And while we are proud of our reputation as the MTF testing experts, our products can measure more than MTF! Ensquared Energy (EE), distortion, chromatic aberrations, and relative illumination are just a few examples of what other kinds of measurements are possible with an OpTest Bench. For example when your system has to perform under pressure, avoiding chromatic aberrations could mean the difference between mission success and critical failure. Chromatic aberrations could shift the apparent position of objects, or skew depth calculations. Missions often depend on pristine imagery, so uncorrected distortions of any kind could make the data unusable. That is why testing with the OpTest Bench is a must for precision-based solutions.

How the OpTest Bench Gets the Job Done

The main subassemblies that go into a base OpTest Bench system can be easily configured for your lens testing needs today, with a variety of upgrade paths that can give you the additional testing capability needed to win future business. But you don’t have to trade accuracy for configurability – our products are meticulously aligned and qualified at your facility to ensure that they meet our industry renowned accuracy and repeatability standards, and our service contract options give you renewed confidence every year that your bench is performing as it should.

A Base OpTest Bench System Comprises the Following:

• An Object Generator (OG) assembly with dual source channels (UV-VIS, or VIS-IR) that illuminate a 16-position target wheel with the desired spectrum via an automated, internal flip mirror assembly, and have the means to filter the source via manual filter drawers or an automated filter wheel
• A reflective, high quality, Off-axis Parabolic (OAP) mirror – with diameter options from 100m to 600mm – used to project the test object at infinity, and a flat, high-quality fold mirror to make the optical path more compact
• A heavy-duty rotary Lens Platform (LP) for precisely rotating the lens under test within the projected object beam for off-axis testing
• Various image analyzer assemblies (video or scanning, for UV, VIS/NIR, SWIR, MWIR or LWIR wavebands) that can relay the image formed by the lens onto a sensor or detector element for analysis
• A precision, three-axis Analyzer Mount (AM) can move the image analyzer in image space to track the image off-axis and through focus, with options for extended travel ranges (up to 200mm for each axis) for large sensor formats or lenses with folded optical paths
• The OpTest 7 software package that provides motion control, data acquisition, and measurement analysis, with modules for real-time measurements and automated test routines

Defense Industry Accessory Highlights for the OpTest Bench

The base system can be modified as described above, or enhanced by adding any (or all!) of the accessories listed below. The accessory list here is far from complete, but highlights the accessories that are most likely to be of interest to the defense industry.

• The VF-1000 Virtual Finite riser assembly places a motorized stage underneath the object generator to move it along the optical axis of the OAP for projecting the test object at different object distances, ranging from beyond infinity to 10s of meters away (or check out our FP-1000 Finite Conjugate Platform for close conjugates)
• Testing folded optics, especially with 90° or 180° optical axis folds, can be accommodated with a combination of upgrades – extended travel AM assemblies, folded Scanning Detectors (SD) that can reach hard to access image planes, custom bench optical axis heights, oversized OAPs or custom periscopic assemblies to point the object beam into an offset entrance pupil, and custom lens fixturing are all options that can be explored.
• The OGA-200 accessory for the OG is a motorized flip mirror accessory with interchangeable optical fiber receptacles that mounts onto the front of the OG and enables the introduction of fiber-coupler lasers to use for narrowband testing or for applications that require a high intensity source
• The TM-1150 Thermal Module is a thermal chamber that can be installed onto the LP and adds image quality temperature testing capability over a lens temperature range of -40°C to 100°C – including the ability to measure focus shifts over temperature – and can accommodate varying lens sizes by adjusting the chamber length using stackable plates.

If you’re not sure what you need, bring your testing requirements to our product engineering team and let us figure it out for you. Reach us anytime at Sales@Optikos.com.