Fabrication and Characteristics of Pyroelectric Infrared Sensors using P(VDF/TrFE) Thick Film for Human Body Detecting

摘要

Pyroelectric infrared sensors have been fabricated using poled P(VDF/TrFE) film. The weight percent and thickness of the poled P(VDF/TrFE) film are 75/25 percent and 25 μm respectively. When infrared absorbed, the P(VDF/TrFE) film expands with increasing temperature. This results in a detectable deformation and corresponding charge generation. The reverse effect occurs on cooling of the film. So the film should be sink thermal energy through sensor quickly for high responsibility, fast response time and low NEP (Noise Equivalent Power) Fast thermal energy sink of the sensor is important for sensors better performance. For this self supporting free standing structure that using no substrate to reduce the thickness of the sensor for fast thermal energy sink. Because melting point of P(VDF/TrFE) film is quite low, an aluminum top and bottom electrode deposited carefully to avoid short circuit during thermal evaporation. The device mounted in a TO-5 housing with silicon window to filter infrared light of 5.5 ～ 14 μm wavelength for human body detecting. The responsibility, NEP and specific detectivity D~* of device were 9.62 x 10~5 V/W, 3.95 x 10~(-7) W and 5.06 x 10~5 cm/W under emission energy of 13 μW/cm~2 respectively.