Optical odor sensors using potential‐sensitive dye coatings

There have been many reports on odor recognition sensors based on multichannel semiconductor gas sensors but few on odor recognition using an optical fiber sensor. Using a fiber‐optic sensor array with potential‐sensitive dye coatings, this paper investigates a sensing system to recognize odor by an optical spectral pattern. The edges of a fiber were coated with films consisting of potential‐sensitive dyes and silicone resin to form a transmission‐type fiber‐optic sensor. When these sensors are exposed to organic vapor odorants, the absorption spectra of the dyes changed, depending on the differences of odorants, indicating that this type of sensor array can be used as an odor‐recognition sensor. Selecting six dyes from 16 dyes, a six‐channel optical fiber sensor array was fabricated. The changes of absorption spectra of dyes were measured and data were processed by a computer. Response patterns to organic vapors were measured and it was confirmed that pattern recognition could be achieved.