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Infrared systems fundamentals
Published in Antoni Rogalski, Infrared and Terahertz Detectors, 2019
The term “FPA” refers to an assemblage of individual detector picture elements (“pixels”) located at the focal plane of an imaging system. Although the definition could include one-dimensional (“linear”) arrays as well as two-dimensional (2D) arrays, it is frequently applied to the latter. Usually, the optics part of an optoelectronic images device is limited only to focusing of the image onto the detectors array. These so-called “staring arrays” are scanned electronically usually using circuits integrated with the arrays. The architecture of detector-readout assemblies has assumed a number of forms. The types of readout-integrated circuits (ROICs) include the function of pixel deselecting, antiblooming on each pixel, subframe imaging, output preamplifiers, and may include yet other functions. Infrared imaging systems, which use 2D arrays, belong to so-called “second-generation” systems.
Infrared devices and techniques
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
Antoni Rogalski, Krzysztof Chrzanowski
The term “focal plane array” (FPA) refers to an assemblage of individual detector picture elements (“pixels”) located at the focal plane of an imaging system. Although the definition could include one-dimensional (“linear”) arrays as well as two-dimensional (2D) arrays, it is frequently applied to the latter. Usually, the optics part of an optoelectronic images device is limited only to focusing of the image onto the detectors array. These so-called staring arrays are scanned electronically usually using circuits integrated with the arrays. The architecture of detector-readout assemblies has assumed a number of forms. The types of readout integrated circuits (ROICs) include the function of pixel deselecting, antiblooming on each pixel, subframe imaging, output preamplifying, and may include yet other functions. IR imaging systems, which use 2D arrays, belong to the so-called second generation systems.
Focal Plane Arrays
Published in Antoni Rogalski, Zbigniew Bielecki, Detection of Optical Signals, 2022
Antoni Rogalski, Zbigniew Bielecki
FPA architecture is shown in Figure 12.7 [4]. Such a system, apart from radiation detection, also performs various functions related to signal processing from individual detection elements. Electronic circuits performing functions of amplifying, signal integration, background subtraction, component non-uniformity compensation, multiplexing and so on, are called readout integrated circuits (ROIC). Arrays of detectors with signal processing in the image plane are developed in the form of monolithic and hybrid arrays [2,16–19].
Electrothermal analysis of a TEC-less IR microbolometer detector including self-heating and thermal drift
Published in Quantitative InfraRed Thermography Journal, 2023
M. Felczak, T. Sosnowski, R. Strąkowski, G. Bieszczad, S. Gogler, J. Stępień, B. Więcek
Section 2 presents and explains the electrothermal model of the ReadOut Integrated Circuit (ROIC) of FPA. In order to investigate self-heating of a bolometric detector, the following sections (3 and 4) present a semi-analytical one-dimensional and a two-dimensional finite element analysis (FEA) heat transfer models of the detector. Section 4 also presents measurement of the self-heating effect in a microbolometer FPA.
CMOS electrochemical measurement circuit for biomolecular detection
Published in International Journal of Electronics, 2018
Wei-Chiun Liu, Shao-Te Wu, Bin-Da Liu, Chia-Ling Wei
In Table 5, the overall performance of the proposed voltammetry potentiostat is summarised and compared with the results in the literature by the measured detection current range, the linearity of the different types, power consumption and the chip’s core area. Ghoreishizadeh et al. (2017) designed a differential readout integrated circuit to measure the differential sensor current and measured current within ±20 μA. This circuit adopted the switch–capacitor technique and used pseudodifferential integrators for concurrent sampling of the differential sensor currents. Chen et al. (2016) presented a high-dynamic range, low-noise CMOS microinstrument chip for electrochemical sensors. The detection range is boosted into ±1 nA–±1 mA by using two readout channels. This chip used the analog-to-digital converter (ADC) to convert the input current from the sensor into digital data. Huang et al. (2015) proposed a voltammetry potentiostat for the electrochemical biosensors, where the measured current in the range of 5 nA–1.2 mA was converted to a frequency-modulated pulse waveform. By means of a current detector circuit and the multi-ratio current copier, the measured current can be scaled to the suitable current magnitude. Martin et al. (2009) developed the new fully-differential potentiostat, which could double the output swing, increase the dynamic range and reduce the susceptibility to common-mode interference. This work emphasizes the redox current sensing circuit of the voltammetry potentiostat system. The designed current range and the redox potential meet the specifications of actual electrochemical measurements. The proposed circuit can generate the clock signal itself for the current-to-time conversion without any external clock input. The measured current range of time readout-type circuit is wider than that of voltage readout-type circuit, but the measured current range of time readout-type circuit can still achieve high linearity when converting the sensed current into time. Moreover, time readout-type circuit can be easily integrated with general digital system and field programmable gate array board. The small chip area of the overall system design allows portable and convenient biomedical applications.