MEMS dew point sensor
MEMS dew point sensor
Keywords: Microelectronics, Sensors
Applicant: Claud S. Gordon Company, Richmond, USA Patent number: US6,126,311 Publication date: 3 October 2000 Title: Dew Point Sensor Using MEMS
This patent describes a dew point sensor including a micro-cantilever beam formed on a substrate. A cooling device and a temperature sensor are in thermal contact with the micro-cantilever beam. A control circuit is coupled to the micro-cantilever beam, the cooling device and the temperature sensor. The control circuit controls and monitors a resonance of the micro-cantilever beam,controls a temperature of the cooling device and receives a temperature indication from the temperature sensor. Using the above information, the dew point temperature is determined by identifying the temperature of the micro-cantilever beam when its resonance changes due to a change in mass caused by the formation of dew on the micro-cantilever beam when the dew point is reached. A method of determining the dew point is also disclosed in which the micro-cantilever beam is excited in a vibratory mode and the temperature of the micro-cantilever beam is decreased. When the temperature of the micro-cantilever beam reaches the dew point, dew forms on the beam, thus changing its mass and causing the resonance of the micro-cantilever beam to change. The resonance of the beam is then monitored to detect the dew point.
