Use of infrared cameras for unattended ground sensors and related applications provide challenges not normally required in hand held systems. This paper discusses the current state of amorphous silicon (a-Si) microbolometer technology as it relates to unattended ground sensor applications. Raytheon has used a-Si detector technology to develop a 160×120 a-Si based infrared camera. This camera, which was originally targeted towards unattended applications, is now in production at Raytheon for hand-held commercial applications. This paper discusses the typical requirements that face unattended ground sensors and how Raytheon's current 160×120 a-Si camera is positioned to meet these requirements.
Amorphous silicon (a-Si) microbolometer technology is a silicon fab-compatible uncooled detector technology which offers a low cost, high volume approach for infrared sensor and imager applications. Raytheon has used this detector technology to develop a 160x120 a-Si based infrared camera. The systems goal was to develop an affordable infrared imaging product that provides acceptable performance for many commercial and military applications. To meet low power goals, a non-temperature controlled detector approach was required. This led to the challenge of developing a technique for operating over ambient temperature that includes correction techniques that account for offset and responsivity non-uniformities over ambient operating temperature. This paper describes the operating performance parameters of a typical a-Si 160 X 120 IR camera. This camera is currently entering production, and will be produced by the Raytheon Commercial Infrared business.
KEYWORDS: Amorphous silicon, Cameras, Infrared cameras, Digital signal processing, Packaging, Microbolometers, Staring arrays, Sensors, Signal processing, Temperature metrology
Low power and low cost are primary requirements for an imaging infrared camera serving law enforcement applications. These include handheld, vehicle and helmet mounted systems for search and surveillance applications. In this paper, a 120 X 160 amorphous silicon (a-Si) microbolometer-based uncooled infrared camera technology offering a low cost, low power solution to infrared surveillance for UGS applications is presented. A 120 X 160 micro infrared camera has been demonstrated which exhibits a noise equivalent temperature difference sensitivity approximately 50 mK using f/1 optics and approximately 80 mK using f/1.2 optics. This sensitivity has been achieved without the use of a thermoelectric cooler for array temperature stabilization thereby significantly reducing the power requirements.
Low power and low cost are primary requirements for an imaging infrared camera used in unattended ground sensor arrays. In this paper, a 120 X 160 amorphous silicon (a- Si) microbolometer-based uncooled infrared camera technology offering a low cost, low power solution to infrared surveillance for UGS applications is presented. A 120 X 160 micron infrared camera (MIRC) has been demonstrated which exhibits an f/1 noise equivalent temperature difference sensitivity approximately 63 mK. This sensitivity has been achieved without the use of a thermoelectric cooler for array temperature stabilization thereby significantly reducing the power requirements. Chopperless camera operation at a 20 Hz frame rate with power consumption of 380 mW has also been demonstrated. The 120 X 160 MIRC operates under digital signal processor (DSP) control. To reduce cost, this DSP-controlled architecture employs commercial off-the-shelf DSP, A/D, memory and voltage regulator chips. The detector chip, employing an integrating amplifier per unit cell ROIC design, is the single custom chip used. The camera also employs low cost f/1 optics, as well as low cost wafer-level vacuum packaging. In this paper, a-Si microbolometer technology for the MIRC will be presented. Also, the key features and performance parameters of the MIRC are presented.
Low power and low cost are primary requirements for an imaging infrared camera used in unattended ground sensor arrays. In this paper, an amorphous silicon (a-Si) microbolometer-based uncooled infrared camera technology offering a low cost, low power solution to infrared surveillance for UGS applications is presented. A 15 X 31 micro infrared camera (MIRC) has been demonstrated which exhibits an f/1 noise equivalent temperature difference sensitivity approximately 67 mK. This sensitivity has been achieved without the use of a thermoelectric cooler for array temperature stabilization thereby significantly reducing the power requirements. The chopperless camera is capable of operating from snapshot mode (1 Hz) to video frame rate (30 Hz). Power consumption of 0.4 W without display, and 0.75 W with display, respectively, has been demonstrated at 30 Hz operation. The 15 X 31 camera demonstrated exhibits a 35 mm camera form factor employing a low cost f/1 singlet optic and LED display, as well as low cost vacuum packaging. A larger 120 X 160 version of the MIRC is also in development and will be discussed. The 120 X 160 MIRC exhibits a substantially smaller form factor and incorporates all the low cost, low power features demonstrated in the 15 X 31 MIRC prototype. In this paper, a-Si microbolometer technology for the MIRC will be presented. Also, the key features and performance parameters of the MIRC are presented.
A new class of uncooled IR systems has been developed based on advances in both amorphous silicon detectors and signal/system processing techniques. Not only are these devices uncooled but they operate over a wide system ambient temperature range without the use of TEC's or choppers. The devices are DC biased and provide radiometric information from each pixel without the use of a calibrated source. The current imaging system are medium to low resolution. They were designed with a very disciplined 'concept-to-cost' technique in which cost, power, sizes, weight and performance were traded off in the stated order. The result has been a new generation of 'ambient temperature' thermal imaging system and radiometers.
An amorphous silicon (a-Si) microbolometer-based uncooled infrared camera technology, offering a low- cost, low-power solution to infrared surveillance for both civilian and military application is presented. A- Si exhibits a temperature dependent resistance with a 3000K temperature coefficient of resistance (TCR) of 2.7 percent/K. The uncooled a-Si microbolometer detector structure employs a low thermal mass a-Si membrane structure with high thermal isolation legs monolithically integrated on a CMOS readout integrated circuit (ROIC) chip. A refractive resonant cavity design results in approximately 90 percent infrared absorptance over the 8-13 um spectral band. A-Si also exhibits a UV/visible photoconductive response for multispectral applications. The ROIC involves an integrating amplifier per pixel and a column multiplexed output. A 15 x 31 micro infrared camera (MIRC) has been developed, which exhibits f/l noise equivalent temperature difference, thereby significantly reducing the power requirements. The 15 x 31 camera demonstrated exhibits a 35 mm camera form factor employing a low cost f/l singlet optic and LED display, as well as low cost vacuum packaging. A larger 120 x 160 version of the MIRC is also in development and will be discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.