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Infrared sensors are the fastest growing segment of a $1 billion a year temperature sensor market. Matt Guerreiri of Raytek explains why.

Explains the problems and opportunities created by the production of gas by decomposition in landfill sites. Describes the infrared and electrochemical methods by which gas can be detected and the typical manner in which these methods are applied. Also describes a PC‐controlled programmable sample system from Crowcon, which is designed for use in landfill sites.

Describes the world's first uncooled infrared array sensor based on micro electro‐mechanical systems technology. Each pixel comprises a cantilever which bends as it warms up. The system measures the capacitance between each cantilever and a metal substrate.

Reports on CARBOCAP®, a new type of optical carbon dioxide sensor, which guarantees high accuracy. States that CARBOCAP® uses a micromachine electrically tuneable Fabry‐Perot interferometer (FPI) as a filter, which guarantees the high accuracy and stability of a dual‐wavelength instrument, without the problems of mismated filters and detectors, or the wear and tear of a rotating filter.

Highlights the use of infrared and ultraviolet for flame detection, emission monitoring and thermal imaging. Describes the application of an infrared fire detection system at Courtaulds Chemicals and the use of thermal imaging for preventive maintenance at Blue Circle Cement.

Applies Fourier transform infrared spectroscopy (FTIR) to the study of lac resin, a complex natural resin of insect origin, and some of its derivatives. Compares the result obtained by this method with those from earlier studies that used classical methods of chemical analysis (the so‐called wet methods). Finds that FTIR has several advantages over the classical methods but, as spectroscopic assignments are still only tentative because of the complex nature of the lac resin, the FTIR data requires supplementing by other instrumental techniques such as FT‐Raman spectroscopy and solid state nuclear magnetic resonance.

Output stability or drift overtime has long been a major performance deficiency for gas sensors irrespective of what technology or methodology is used for their conception. Software correction may alleviate the problem somewhat but it is not always applicable. It has long been the objective of many researchers in this field to overcome this problem fundamentally and for good. The purpose of this paper is to show that this objective has now finally been achieved.

Conventional non‐dispersive infrared (NDIR) dual beam methodology utilizes the ratio of signal channel output over reference channel output for signal processing. The signal filter overlaps the absorption band of the gas of interest while the reference filter does not. However, this ratio changes as the source ages. The current methodology uses an absorption bias between signal and reference channel outputs. This absorption bias is created by using a path length for the signal channel greater than that for the reference channel. Both the signal and reference detectors carry an identical spectral filter overlapping the absorption band of the gas to be measured.

Implementation of the currently patented NDIR gas‐sensing methodology has been carried out in different gas sensor configurations for over a year in the laboratory. Performance results for these sensors showing insignificant output drifts overtime have been repeatedly demonstrated via simulated aging for the source.

The paper puts forward the view that the recent breakthrough of the Near Zero Drift methodology for NDIR gas sensors will very quickly change the hierarchy of technology dominance and utility for gas sensors at large.

There are a lot of applications available for infrared focal plane array (IRFPA). Thus, advanced functions are required to support a wide range of IRFPAs applications. The purpose of this paper is to present a control circuit for a user reconfigurable 320×256 readout integrated circuit (ROIC) designed for IRFPA applications.

In order to implement reconfigurable ROIC, several advanced functions can be realized by the control circuit such as global reset, capacitive transimpedance amplifier (CTIA) gain selectable, CTIA bandwidth selectable, random access opening (RAO), dynamic image transposition, selectable outputs, and adjustable power dissipation. These advanced functions can be implemented by loading corresponding control words into a 60‐bit control register. There are seven types of control words available with 14‐bit control words reserved for the realization of other functions in the future to control corresponding seven advanced functions.

Design and simulation of the control circuit based on CSMC 0.5 μm process technology have been conducted to confirm these functions. Based on these functions, wide scene dynamic range can be achieved, and the application of ROIC is more flexible.

This paper describes more functions such as CTIA bandwidth selectable, global reset, and also improved functions of RAO.