Spectralon Disposable Calibration Standards for Medical Diagnostics

May 19, 2020

Labsphere was approached by a start-up company which used their fiber-coupled spectrometer-based device to make reflectance measurements through the instrument channel of an endoscope. In order to get accurate diagnostic results, the instrument needed to calibrate before each use against a standard with >90% reflectance. However, this novel medical diagnostic application required disposal of the standard after each use. The company approached Labsphere seeking a highly repeatable, low-cost solution to enable their device to achieve market penetration.

Of particular concern was the consistency in calibrating the instrument, so every standard produced by Labsphere would need to be extremely repeatable both mechanically in mounting to the fiber and optically in its diffuse reflectance factor across the visible spectrum (450-700 nm). Prototypes were needed quickly, but capacity to produce 10K-25K pieces annually at market pricing was paramount.

Labsphere produced a simple design to achieve both the quick turnaround of prototypes and the cost targets at high volume, while optimizing technical performance.

The optical reflectance objectives were met by die cutting Labsphere’s Spectralon® from 3 mm thick sheets to yield a consistent 97% reflective, Lambertian target material. Statistical process control sampling of Spectralon production ensured consistent reflectance performance.

The mechanical objectives were met by designing in repeatability. The design comprised a snap-together Delrin housing that contained the Spectralon target backed by a foam adhesive. The fiber port was designed to fit tightly to the customer’s fiber with a raised bottom lip to position the fiber tip a customer-specified, precise distance from the target reference surface. The foam adhesive behind the target was designed to be partially compressed when the halves of the unit were snapped together to ensure the target was held against the reference surface, eliminating variation in the critical distance from fiber tip to target.

The cost and delivery objectives were met by choosing a medical instrument-compatible material (Delrin) for the housing that could be machined in-house by Labsphere for fast prototyping, but also injection molded in high quantities to achieve target production unit pricing.

This innovation has lead to numerous other uses for Spectralon components for the medical and biomedical industries. Contact us for information on using Spectralon for your applications.