01 Feb 2011 New thin film pyroelectric sensors, fast switching IR sources and suitable gas cell design enable new levels of ppm detection levels. Tighter legislation on environmental polutants and a public desire for green products, NDIR technology is one way to monitor a range of gases and VOCs with single, or multiple colour, detection in real time in both the home and industry. Using a 1μm thick sputtered PZT Perovskite structure (111), a permanent polarisation pyroelectric detector can be produced with the benefits of semiconductor manufacture due to its MEM’s design flexibility with selective wet and dry etches. These devices have a Curie point above 500degC and are extremely stable. They exhibit low noise (no noise spikes, no popcorn noise, low Johnson noise), and with an integrated OpAmp high output signals are achieved. Based on 14 Patents with a further 10 Patent applications, this Siemens' technology offers an unprecidented new range of detectors, which span the 0.1μm to THz region. Optional black layer(s) can be added for enhanced performance over selected wavelengths e.g. NIR or THz. Detectors in the NIR region are proving to be formidible devices compared to lithium tantalate pyroelectric detectors for NDIR gas sensing applications . Using either an IR emitter, typically pulsed between 1-10Hz, or light from the object of measurment, such as a flame, and narrow bandpass optical filters, gas detection levels from sub-ppm to 100% can be achived. With two, four or more channels, multiple gases may be simultaneously measured in real time, including volatile organic compounds (VOCs), which can affect the environment and human health. VOCs build up slowly inside buildings. With the increased use of man-made fabrics in carpets and furniture that emit VOCs, there is increased interest for passive detection inside homes and offices.
For more information visit our website at:NDIR Pyroelectric Detector Sensors! |
