Documents / Report
This Defense Intelligence Agency reference document, dated 31 March 2010 (DIA-08-1003-020), was one of a series of advanced technology reports produced in FY 2009 under the Advanced Aerospace Weapon System Applications (AAWSA) program. It surveys biosensors and BioMEMS, covering brain-implanted neuroelectrodes, drug-delivery pumps, implantable glucose sensors, brain-machine interfaces, retinal prostheses, microfluidic lab chips, NASA cell culture systems, and microcantilever sensors. It concludes that the field is expanding rapidly toward nanomechanical systems.
“University of Arizona”7 pages
UNCLASSIFIED/ ,'1"91'1 8l"l"ll!lo\l, Wili liUI._¥
drift and offset in the reading and so shifting the calibration. Depending on its exact
construction some versions however can be effective for as much as a few days.
Figure 8 shows the latest in microdevice oxygen sensors. (This particular version is not
specifically a MEMS device since it is not made by photolithography and it is neither
g_lectrical nor mechanical in nature.) It represents however the trend in oxygen sensors
towards optical measurement techniques that are evolving towards optical systems
based on MEMS. These sensors can be implemented in small sizes with optical fibers
that transmit and receive light from the sensor surface at the tip. Variations on this
basic principle are used for indwelling blood oxygen catheters during surgery.
fiber optrcs ,-_,..____
silicone cover \ ......
~"'..~ -...... ~ prism
• ({ ~
' (/
silicone carrier
•
Figure 8. A Fiber Optical Oxygen Sensor Showing Two Optical Fibers Mated to Plastic Prisms That are
Coated With an oxygen-sensor Coating, Usually a Fluorescent Ruthenium Compound
(http://www.1mtek.de/content/projekte_en .php ?Is= 11)
The oxygen sensors respond to changes in absorption of oxygen into the special coating
at the tip, or in some versions, they respond to fluorescence of a thin oxygen-sensitive
coating placed on the prism surface. The secret to good performance lies in the
proprietary selection of the specific chemical species selected for the coating.
Blue light is usually transmitted down the optical fiber and the coating glows orange in
proportion to the amount of oxygen present. The light from the glow is conducted back
toward the supporting instrumentation system. The intensity of the orange light then
indicates oxygen levels in the solution. The particular sensor shown in Figure 8 uses
two optical fibers. The one on the left side is not sensitive to oxygen, but rather acts as
a reference system that is used to compensate for changes temperature, ambient light,
and other system variables.
12
UNCLASSIFIED/ ,'f811. 8ffiiiiR.k Yili &•l._l/' Not linked to a story yet.
Report, from the dia collection. The PDF is mirrored here; the original link is under it. 45 pages are in the text index: search them above, or from the library's search.