High-sensitivity pyroelectric linear arrays and their a

摘要

Abstract: Pyroelectric infrared detectors have among other things the known advantages of being able to be used at room temperature and of being provided with a sufficient signal- to-noise ratio for a number of applications, a spectral responsivity of a relative homogeneity within the infrared range, and properties of a very long-term stability. For extending their range of application both extensive and intensive efforts were made, during the last few years, to considerably improve responsivity, noise equivalent power (NEP) and modulation transfer function of linear arrays. The paper describes the structure and the main properties of newly developed line sensors based on lithium tantalate and containing 128 sensitive elements (size of element: 90 $MUL 100 $mu@m$+2$/, pitch 100 $mu@m). It is shown that the thickness of the responsive elements has a strong influence on responsivity. Special techniques for structuring the pyroelectric chip and using a low-noise CMOS read-out circuit made it possible to achieve NEP values below 0.5 nW at a chopper frequency of 40 Hz. Illustrated by the examples of a line scanner and a 2D camera, the paper proves that noise equivalent temperature difference values around 0.1 K are possible.!9