2011

Understanding Infrared Detector & Emitter Technology

This superior measurement stability is made possible by three key factors. First, the 256-element array (consisting of six compensation elements and 250 active elements) provides real-time measurement compensation for environmental changes. The measurement is adjusted based on a comparison of the six compensation elements and three active elements on each side of the array. Secondly, the new array design reduces the effects of system noise by up to 10%, optimizing the measurement resolution. Finally the arrays built-in shielding isolates the array from environmental variables that could reduce measurement accuracy.

A new feature is an optional cooler controller that further optimizes measurement stability by providing the means to fine-tune the temperature set point via included software, allowing the array to be set at the optimal operating temperature for a particular application.

PbS and PbSe arrays are ideally suited for a range of applications including gas analysis, spectroscopy, process and quality control, and thermal imaging/hotspot detection in applications such as manufacturing and assembly process lines or in buildings and railway systems.

Infrared Emitters

altHigh-output, high-pulse rate emitters can be pulsed as a source of blackbody radiation for near-to-mid infrared applications and are compatible with a wide range of infrared detector technologies. Whereas alternative emitter technologies pulse at roughly 10 Hz with 50% modulation, the latest generation of infrared emitter technology introduced in 2010 features a pulse speed that is 18 times faster (typically 180 Hz with 50% modulation depth), allowing users to obtain accurate readings of materials with much lower parts per million concentrations. Furthermore, these high pulse speeds are obtained without the added expense of having to design and implement optical choppers or mechanical modulators, as is often done with incandescent bulb emitters, and covers a much wider spectrum than high-pulsing infrared LEDs, which focus on only very narrow bandwidths.

The newest pulsable emitters come with integrated drive electronics in an industry standard 14 pin-dip IC package. The user-friendly drive electronics are voltage variable and allow users to select from a wide range of frequencies between 1Hz and 200Hz according to their specific application needs. A special feature of the drive electronics is the ability to provide peak pulse temperatures independent of the pulse frequency. This ensures the highest output for any application.

Target applications include industrial and medical gas analysis, environmental monitoring, process control instrumentation, spectroscopy, and plastics sorting.

Conclusion

In conclusion, lead salt detector technology offers significant performance and value benefits compared to alternative infrared technology options. The past two years in particular have witnessed significant enhancement to single-element, multi-element and array lead salt technologies.

When selecting a lead salt detector and emitter supplier, factors to consider include detector quality, process control and integration support. Selecting a supplier with expertise in detectors, emitters, packaging and drive controllers/software helps ensure optimized performance. Ask for a list of recent technology introductions to ensure your provider is keeping their finger on the pulse of developing technologies. Finally, make sure significant product design support is provided via prototyping tools such as digital drive boards and access to technical experts.

This article was written by Cary Moreth, VP and General Manager, ITW Photonics Group (Santa Rosa, CA). For more information, contact ITW Photonics Group at This email address is being protected from spambots. You need JavaScript enabled to view it., or visit http://info.hotims.com/34456-200.