Pyroelectric devices advantages

Pyroelectric infrared detectors are inferior in detectivity by one or two orders of magnitude compared with photoconductors such as cadmium mercury telluride, as shown in Fig. 7.15. However, such materials require temperatures of 200 K for efficient operation and generally respond to rather narrow bands at the infrared wavelengths. Pyroelectric devices can discriminate temperature differences of 0.1 K but find many useful applications in which the discrimination is limited to about 0.5 K. They have the great practical advantage of operating at normal ambient temperatures. 

The pyroelectric element is likely to be a specialty device, though it is far too soon to tell. Its primary advantage is that it can permit time integration of the species of interest and as a result can be used to detect extremely small concentrations. The most that can be said at the present is that more research is clearly needed for this structure. 

Table I, provided yet another instrumental approach for balloon experiments intended to measure the extinction of solar radiation by stratospheric aerosol. Spectrometer 4, Table I, based on the use of a pyroelectric vidicon image device, was developed to measure the strong absorption bands of non-isonuclear molecules ( 2-5 ym range). Recently we have developed spectrometer 5, Table I, based on the use of a self-scanned solid state pyroelectric array sensor. The main advantages of this sensor, over the pyroelectric vidicon, are its improved sensitivity and reduced channel-to-channel cross-talk.

Electroactive polymers have piezoelectric and pyroelectric properties that are lower than those of ceramics materials. However, they have low permittivity as well as other advantages that enable their use in applications (Lang, 2008) such as acmators, vibrational control, ultrasonic transducers, and others such as shock sensors, health monitoring, tactile sensors, and energy conversion devices. 

PVDF are commercially available (Siemens, Microwatt Applications). The relatively low pyroelectric coefficient of PVDF and, to some extent, the difficulty of handling small pieces of the thinnest films seem to have inhibited its more widespread adoption in practical devices. The availability of large active areas does not of itself seem to have provided sufficient advantage to device engineers. 

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