초록 ▼

A dew point sensor includes a micro-cantilever beam formed on a substrate. A cooling device and a temperature sensor are in thermal contact with the micro-cantilever beam and a control circuit is coupled to the micro-cantilever beam, the cooling device and the temperature sensor. The control circuit

A dew point sensor includes a micro-cantilever beam formed on a substrate. A cooling device and a temperature sensor are in thermal contact with the micro-cantilever beam and 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. The method includes exciting a micro-cantilever beam in a vibratory mode and decreasing a temperature of the micro-cantilever beam. When the temperature of the micro-cantilever beam reaches the dew point, dew forms thereon, thus changing its mass which causes a resonance of the micro-cantilever beam to change. The resonance of the beam is then monitored to detect the dew point.

대표청구항 ▼

[ What is claimed is:] [1.] A dew point sensor, comprising:a micro-cantilever beam formed on a substrate;a cooling device in thermal contact with the micro-cantilever beam;a temperature sensor in thermal contact with the micro-cantilever beam; anda control circuit coupled to the micro-cantilever bea

[ What is claimed is:] [1.] A dew point sensor, comprising:a micro-cantilever beam formed on a substrate;a cooling device in thermal contact with the micro-cantilever beam;a temperature sensor in thermal contact with the micro-cantilever beam; anda control circuit coupled to the micro-cantilever beam, the cooling device and the temperature sensor, wherein the control circuit is operable to monitor a resonance of the micro-cantilever beam, control a temperature of the cooling device and receive a temperature indication from the temperature sensor, thereby identifying the temperature of the micro-cantilever beam when the resonance of the micro-cantilever beam changes due to a change in mass caused by dew on the micro-cantilever beam when the dew point is reached. [15.] A method of determining the dew point, comprising the steps of:exciting a micro-cantilever beam in a vibratory mode;decreasing a temperature of the micro-cantilever beam, wherein when the temperature reaches the dew point, dew forms on the micro-cantilever beam and changes the mass of the micro-cantilever beam which causes a resonance of the micro-cantilever beam to change; andmonitoring the resonance of the micro-cantilever beam, wherein a change in the resonance determines the dew point. The method of claim 15, wherein exciting the micro-cantilever beam into a vibratory mode comprises applying an electrical signal to a piezoelectric material which is coupled to the micro-cantilever beam, wherein the electrical signal causes the piezoelectric material to deform, thus causing the micro-cantilever beam to vibrate at a resonant frequency. The method of claim 15, wherein decreasing the temperature of the micro-cantilever beam comprises the step of thermally coupling a cooling device to the micro-cantilever beam. The method of claim 15, wherein decreasing the temperature of the micro-cantilever beam comprise the steps of:forming a plurality of thermoelectric elements in thermal proximity to the micro-cantilever beam; anddriving the thermoelectric elements to cool the micro-cantilever beam to a temperature at which the dew point is reached. The method of claim 15, further comprising the step of identifying a temperature of the micro-cantilever beam at which the resonance changes.