<title>Uncooled infrared sensors with digital focal plane array</title>

Abstract

Loral Infrared & Imaging Systems is developing low cost, high performance, uncooled infrared imaging products for both military and commercial applications. These products are based on the microbolometer technology, a silicon micromachined sensor which combines the wafer level silicon processing with a device structure capable of yielding excellent infrared imaging performance. Here, we report on the development of an uncooled sensor, the LTC500, which incorporates an all digital focal plane array and has a measured NETD of less than 70 mK.The focal plane array and the electronics within the LTC500 have been designed as an integrated unit to meet a broad range of end user applications by providing features such 'as nonuniformity correction, autogain and level, NTSC video, and digital outputs. The 327 x 245 element focal plane array has a 46.25 Itm pixel pitch and an on focal plane array 14 bit to analog to digital converter (ADC). The ADC has a measured instantaneous dynamic range of more than 76 dB at a 6.1 MHz output data rate and 60 Hz frame rate. The focal plane array consumes less than 500 mW of power, of which less than 250 mW is usedin the ADC-. An additional 36 dB of digital coarse offset correction in front of the ADC on the focal plane array results in a total electronic dynamic range of 112 dB. The MRT of the LTC500 camera has been measured at less 0.2 C at f0.

GOALI: Systems Integration of Uncooled YBaCuO IR Detectors

“…This is considerably lower than the noise exhibited by VO x and a:Si microbolometers. [34,35] The responsivity, detectivity and noise equivalent power were calculated from the measured voltage response and noise in vacuum at room temperature and are plotted in Figure 18 as a function of chopper frequency for two bias currents. The NEP reported here is calculated per root Hertz bandwidth for convenience.…”

Two-dimensional micromechanical bimorph arrays for detection of thermal radiation

“…R. Manalis We demonstrate that two-dimensional arrays of micromechanical bimorphs can be used as thermal sensors to image infrared ͑IR͒ radiation. A density of 100 pixels per mm 2 is achieved by coiling a bimorph beam into the shape of a flat spiral. Temperature variations of a given spiral are converted to modulations of visible light by illuminating the spiral array with a visible source.…”

“…The most recent systems achieve a sensitivity that approaches the thermal limit and operate at speeds of 60 frames/s. [1][2][3] Images with high spatial resolution are obtained from arrays containing 400 pixels per mm 2 by reading electronic signals generated at each detector. In order to process this information, multiple transistors are integrated into each pixel and a separate device is used to display the image.…”

“…For comparison, the temperature resolution, NEP, and response time of a commercial bolometric IR detector with a 46 m pixel size is roughly 20 K/ͱHz, 0.004 nW/ͱHz, and 12 ms, respectively. 2 Although the temperature resolution of In ͑b͒, ϳ100 W of power from the IR laser is absorbed by the spiral. The resulting temperature change causes the spiral to distort and the focal point intensity is reduced.…”

System for Detection and Control of Deposition in Kraft Chemical Recovery Boilers and Monitoring Glass Furnaces

“…Recently, ferroelectric and microbolometer detector arrays have become commercially available from a number of sources including Raytheon [12], LIRIS [13], Amber Engineering [14], the Santa Barbara Research Center [15] and the ULTRA Consortium [16] consisting of Honeywell, Rockwell, Inframetrics and the New Jersey Institute of Technology. These devices are relatively inexpensive and do not require cooling, making them suitable for boiler applications.…”