NDIR technology monitors gases and VOCs

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.

New thin-film pyroelectric sensors, fast-switching IR sources and suitable gas-cell design enable new levels of ppm detection.

Using a 1um-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 500C and are extremely stable.

They exhibit low noise (no noise spikes, no popcorn noise, low Johnson noise) and, with an integrated Op-Amp, high output signals are achieved.

Based on 14 patents with a further 10 patent applications, this Siemens' technology offers a new range of detectors that span the 0.1um to THz region.

Optional black layers can be added for enhanced performance over selected wavelengths.

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 measurement, such as a flame, and narrow bandpass optical filters, gas-detection levels from sub-ppm to 100 per cent can be achieved.

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.

Back to top