Development of a miniaturized optical viscosity sensor with an optical surface tracking system

H. Abe, R. Nagamachi, Y. Taguchi, Y. Nagasaka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


A new viscosity sensor enabling non-contact measurement at high speed, with less sample volume and high stability is required in a broad field. For example, in the industrial field, process control by real time monitoring of viscosity can enhance the quality of coating films and the process yield such as conductive films and optical films. Therefore, we have developed a new miniaturized optical viscosity sensor, namely MOVS (Miniaturized Optical Viscosity Sensor), based on a laser-induced capillary wave (LiCW) method which can meet the requirements above. In the MOVS, viscosity is estimated by observing the damping oscillation of LiCW, which is generated by an interference of two excitation laser beams on a liquid surface. By irradiating a probing laser on LiCW, a first order diffracted beam containing information of sample viscosity, is generated. The intensity of the reflected beam is utilized to control the distance between liquid-level and the sensor. The newly integrated optical surface tracking system makes possible the stable viscosity measurement in the presence of disturbance such as evaporation and external vibration. MOVS consists of five U-grooves fabricated by MEMS (Micro Electro Mechanical Systems) process to possess the optical fibers (photonic crystal fibers and fusion-spliced lensed fibers). In this study, by integrating the optical surface tracking system on the chip, nanosecond order damping oscillation of LiCW is successfully observed in the presence of external forced vibration, high speed evaporation (speed of 1 micrometer per second) and drying process of a liquid film (thickness of hundreds micrometer order).

Original languageEnglish
Title of host publicationMOEMS and Miniaturized Systems IX
Publication statusPublished - 2010
EventMOEMS and Miniaturized Systems IX - San Francisco, CA, United States
Duration: 2010 Jan 252010 Jan 27

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherMOEMS and Miniaturized Systems IX
Country/TerritoryUnited States
CitySan Francisco, CA


  • In situ measurement
  • Micro fabrication
  • Non-contact measurement
  • Optical sensing
  • Surface tracking system
  • Viscosity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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