Solid-state pyroelectric infrared image converter

Abstract

The following paper outlines a technique for construction of solid-state pyroelectric infrared detector arrays. Four major problems associated with pyroelectric detector arrays in general and solid-state pyroelectric detector arrays in particular are addressed: (1) sensitivity, (2) spatial resolution, (3) heat loading of the substrate and finally (4) a technologically feasible fabrication technique. It is shown that excellent sensitivity and high spatial resolution can be obtained with a combination of a high chopping rate and electronic signal integration in a separate memory. With 100 lp/cm resolution, 50 μm elements, the optimum chopping rate is high enough that there is little or no substrate heat loading effect. Thus, hybrid detector fabrication utilizes technologically simple flip-chip bonding or wire bonding techniques. Calculations based on reports of current performance of CCD multiplexing electronics predict that with electronic signal integration to an equivalent frame rate of 15 Hz and at 100 lp/cm spatial resolution, a minimum resolvable temperature of 0.25°C is achievable. This performance is about a factor of 10 better than the present performance of the state of the art pyroelectric vidicon at the same spatial resolution. A developmental 32 element linear detector array on 4 mil centers with self-scanned FET multiplexing electronics has been constructed. Preliminary array characteristics are reported. The above techniques are patented.