Micro thermal diode with glass thermal insulation structure embedded in a vapor chamber

Takashiro Tsukamoto, Takashi Hirayanagi, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


This paper reports a micro thermal diode based on one-way working fluid circulation driven by surface tension force. In forward mode, working fluid evaporates and condenses at a heated and cooled area, respectively, and the condensed liquid returns to the evaporation area due to the wettability difference. By this vapor-liquid phase change mechanism, the overall heat transfer coefficient becomes high. On the other hand, in reverse mode, no continuous evaporation-condensation cycle exists. The conductive heat loss in reverse mode was minimized by an embedded glass thermal isolation structure, which makes overall heat transfer coefficient low. The test device was made by a standard MEMS process combined with glass reflow and gold bump sealing. The overall heat transfer coefficients of 13 300 W m-2K for forward mode and 4790 W m?2K for reverse mode were measured. The performance index of the micro thermal diode was about 2.8.

Original languageEnglish
Article number045001
JournalJournal of Micromechanics and Microengineering
Issue number4
Publication statusPublished - 2017 Feb 21


  • embedded glass structure
  • surface tension driven droplet actuation
  • thermal diode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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