Miniature precision in biophotonics

20 Nov 2012

Thanks to the progress in miniaturising optical components and systems, new fields of application are opening in biophotonics on a regular basis. Miniaturised solutions provide novel therapies and diagnostics that would not be possible with conventional systems; however, innovative solutions also have to meet commercial criteria. Their deployment is only justified if the cost of treatment can be reduced compared with conventional methods. This also means that it must be possible to produce such systems commercially in larger numbers.

Non-contact optical measuring technology is an essential component of biophotonics, meeting the demands of new developments in personal healthcare; the technology makes it possible to measure blood sugar levels to provide evidence of, for example, infectious diseases. It is also used for non-contact topographical measurement.

The miniaturised photonics system can be used in the field of medical technology. The compact measuring sensor makes it possible to measure very small cavities in 3D and any type of surface. The process involves the principle of spectrally coded fringe projection. This makes it possible to measure 2D and 3D object topographies faster and easier compared with simple point or light section triangulation processes. For this purpose, the optical sensor consists of a stripe projector (illumination unit), imaging optics for the reflected light signal and the receiver unit, which records the signal. The sensor also contains a front camera for visual navigation in the cavity in order to prevent collisions. The optical system is divided into four functional groups and comprises a total of 14 lenses (diameter of 1–2.7mm and an average thickness of 0.15mm) and three shutters that are configured in five cemented lenses. The cameras for light signal reception and navigation are placed on a print.

The fabrication and assembly of the micro-optics are extremely challenging. In view of the required illumination and imaging qualities, the optical subsystems have to be actively adjusted and fixed using a specially developed cementing process. Such processes often have to be developed in parallel with the design, particularly for miniaturised systems to ensure cost-efficient scaleability.

FISBA OPTIK supplies complete photonic systems that can be integrated into the final product by industrial customers. These may be measuring sensors, but also miniaturised cameras for video-assisted endoscopy, illumination and imaging systems for fluorescence diagnostics, through to micro-projectors for the consumer market. Application-specific solutions are developed in close cooperation with the customer prior to serial production