To overcome the range limitation of traditional flow sensors,a flexible substrate MEMS thermal flow sensor based on double helix structure heater is proposed.To reduce the heat conduction loss,an uniform through-hole array is made on the substrate.Two pairs of temperature measurement resistors are symmetrically distributed on both sides of the heater,resulting in a wide range and high sensitivity at both small and large flow.The output voltage is measured using a detection circuit based on Wheatstone bridge,at the same time,maintain a constant temperature difference of 200 K between the heater and the ambient temperature to compensate for the self-heating of the resistor.The operating temperature of the sensor is-100～400℃,and the range is 0～60 m/s.The sensitivity is about 12.75 V/(m·s-1)at low flow rates with a resolution of 0.001 mm/s,the sensitivity is about 1.4 mV/(m·s-1)at a high flow rate.The power consumption is as low as 1.3 mW.
关键词
微机电系统/热流量/双螺旋结构/热温差式/柔性
Key words
MEMS/heat flow sensor/double helix structure/thermal temperature difference type/flexible
维普
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