Pyroelectric Infrared Sensor Research Articles

Characteristics of pyroelectric sensors of polyurea films prepared by vapor deposition polymerization

Pyroelectric infrared (IR) sensors were fabricated from aromatic polyurea by vapor deposition polymerization. Voltage sensitivity ( R v ), noise voltage, and detectivity ( D∗(500,1,1)) of a sensor fabricated on a glass substrate were 2.6 V W −1, 0.35 μV, and 3.3 × 10 6 cm Hz 1 2 W −1 , respectively. R v and D∗ were increased by improving thermal insulation and thermal absorption efficiency, and by employing a multi-pyroelectric layer structure. An IR sensor fabricated on a thermally insulated Si wafer had better frequency characteristics than a sintered LiTaO 3 ceramic sensor. The rise time of the sensor was about 6 ms. A pyroelectric linear array of 128 sensor elements fabricated on a thermally insulated Si wafer showed an average voltage sensitivity and detectivity of 4000 V W −1 and 1 × 10 6 cm Hz 1 2 W −1 , respectively.

Pyroelectric infrared sensors made of La-modified PbTiO3 thin films and their applications

Abstract High sensitive pyroelectric infrared (IR) sensors have been fabricated by using c-axis oriented La-modified PbTiO3 (Pb1–xLaxTi1−x/4O3, PLT) thin films. The PLT thin films were deposited on (100)-cleaved MgO single crystal substrates by intermittent rf-magnetron sputtering method. The PLT thin films have high figures of merit for IR sensor without a poling treatment. High performance pyroelectric IR sensors (single element type and linear array type) were fabricated by using PLT (x=0·1, γ=5·5x10−8 C/cm2K, ϵr=200) thin films. The sensors have remarkably high D* of 3–6x108 cmHz1/2/W and very fast response. A new compact IR sensing system using the linear array sensor (8 elements) has been developed for a new type of room air-conditioner. This system can measure thermal distribution (8x64) by horizontal scanning of the vertical linear array. Image processing with neural network concept makes possible high-accuracy using a few data from the sensor elements. This sensing system provides ‘‘smart aircond...

A miniature, battery-powered, pyroelectric detector-based differential infrared absorption sensor for ambient concentrations of carbon dioxide

Abstract We describe a dual-wavelength, non-dispersive, spectro-radiometer that is optimized to measure carbon dioxide. This CO2 sensor was designed for use with a portable system for measuring water loss and photosynthesis in plant leaves. The elements of the sensor include: a highly insulated, miniature, blackbody source of infrared radiation; an external, folded, optical-absorption cell; alternating, narrow-band pass filters; and a commercial pyroelectric detector. Detector signals are filtered, amplified, and fed to a processing system based on a voltage-to-frequency converter that computes a ratio of the absorbed wavelength to a non-absorbed wavelength. The system, minus battery, weighs less than 1.5 kg and its optical head volume is 800 cm. The sensor requires 10 W of power from a 12-V source, and has an accuracy of about ±0.5 ppm at ambient (330 μ1/1) concentrations.