Jahresbericht 2005 - IPHT Jena
Jahresbericht 2005 - IPHT Jena
Jahresbericht 2005 - IPHT Jena
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The operation principle is based on frustrated<br />
total internal light reflection on the glass-air interface<br />
in the presence of dew drops or ice crystals<br />
(patented by Bartec).<br />
The optical principle is shown in Fig. 2.29. Essential<br />
features of the new dew point hygrometer are<br />
the application of a transparent light guiding<br />
glass slide and the reverse illumination of the<br />
glass-gas interface through glass.<br />
Fig. 2.29: Scheme of the sensor principle.<br />
Without condensed water on the glass surface,<br />
the light from a LED propagates without losses<br />
through the light guide to the photodetector. If<br />
condensed dew droplets are on the glass surface<br />
the light penetrates the glass-droplet interfaces<br />
and is scattered at the droplet-air interface. This<br />
results in a decrease of the intensity at the detector.<br />
The advantage of this principle is the ruggedness<br />
in relation to contamination.<br />
Fig. 2.30: Optical waveguide with platinum resistance<br />
thermometer.<br />
Fig. 2.31: Condensation on the glass surface.<br />
OPTIK / OPTICS<br />
To precise measure the dew point temperature, a<br />
platinum resistance thermometer with contact<br />
structures has been deposited on the glass surface<br />
(see Fig. 2.30). The platinum structure is<br />
arranged in the thermoelectric cooled condensation<br />
area. For passivation, the measuring structure<br />
is coated by a thin silicon carbide overlay to<br />
protect the electrical resistance structure. Fig.<br />
2.31 shows a microscopic photo of condensed<br />
water droplets on the sensor surface.<br />
With the presented sensor, an accuracy of ±0.5 K<br />
for the dew point temperature in the range of –15<br />
to +20 °C DP has been measured.<br />
2.3 Appendix<br />
Partners<br />
1. Industrial partners<br />
• Advanced Optic Solutions GmbH, Dresden<br />
• Analytik <strong>Jena</strong> AG<br />
• AIFOTEC Fiber Optics GmbH, Meiningen<br />
• BARTEC Messtechnik & Sensorik GmbH<br />
• Carl Zeiss <strong>Jena</strong>, Oberkochen<br />
• CeramOptec GmbH, Bonn<br />
• Crystal Fibre A/S Lyngby, Dänemark<br />
• DaimlerChrysler AG, Forschungszentrum Ulm<br />
• DSM Research, Geleen, Niederlande<br />
• EADS München-Ottobrunn<br />
• Electro-optics Industries Ltd., Israel<br />
• EPSA GmbH Saalfeld/<strong>Jena</strong><br />
• j-Fiber GmbH,<strong>Jena</strong><br />
• FiberTech GmbH, Berlin<br />
• fiberware GmbH, Mittweida<br />
• FISBA Optik, St. Gallen/Schweiz<br />
• GESO GmbH, <strong>Jena</strong><br />
• GRINTECH GmbH <strong>Jena</strong><br />
• Heraeus Quarzglas GmbH & Co. KG<br />
• Heraeus Tenevo AG<br />
• Hottinger Baldwin Messtechnik GmbH, Darmstadt<br />
• Hybrid Glass Technologies, Princeton, USA<br />
• I.D. FOS Research, Geel, Belgien<br />
• Jenoptik Laserdiode GmbH<br />
• Jenoptik L.O.S. GmbH<br />
• Jenoptik LDT GmbH, Gera<br />
• Jenoptik Mikrotechnik GmbH<br />
• Jenoptik Laser Solution GmbH<br />
• <strong>Jena</strong>-Optronik GmbH<br />
• JETI GmbH <strong>Jena</strong><br />
• Kayser & Threde GmbH München<br />
• Laserline GmbH Mühlheim-Kärlich<br />
• Layertec GmbH Mellingen<br />
• Leica Microsystems Wetzlar<br />
• Mikrotechnik & Sensorik GmbH <strong>Jena</strong><br />
• NTECH Technology, Novara, Italy<br />
• ONERA Paris Palaiseau /Frankreich<br />
• OVD Kinegram Corp., Zug, Schweiz<br />
• piezosystem jena GmbH<br />
• ROFIN SINAR Laser GmbH Hamburg<br />
• Schott Glas, Mainz<br />
• Schott Lithotec AG, <strong>Jena</strong><br />
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