Figure 9 - uploaded by William Arthur Radford
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Front and back views of the C&CE flex-rigid circuit card assembly. The tight 3GFSE packaging requirements resulted in partitioning the video buffer circuitry and low-noise bias voltage generation circuitry onto small rigid boards attached to the main C&CE board via flex-cables.
Source publication
Raytheon has developed a 3rd-Generation FLIR Sensor Engine (3GFSE) for advanced U.S. Army systems. The sensor engine is based around a compact, productized detector-dewar assembly incorporating a 640 x 480 staring dual-band (MW/LWIR) focal plane array (FPA) and a dual-aperture coldshield mechanism. The capability to switch the coldshield aperture a...
Context in source publication
Context 1
... tight 3GFSE volume requirements led to a flex-rigid approach to the C&CE circuit card assembly. The assembly consists of three 9-layer rigid sections interconnected using three flexible layers (see Figure 9). This flexibility permits the C&CE to wrap closely around the dewar and eliminates the need for space-consuming connectors. ...
Citations
... However, when flying at night only the emissive bands can aid in obstacle detection. FLIR and Lockheed-Martin both utilize the mid-wave infrared and the long-wave infrared in their electro-optical sensor systems for pilotage and targeting [3,4]. These bands range from 3-5 µm and 8-14 µm respectively and are critical for identifying objects at night. ...
The signal to noise ratio and corresponding visibility of power cables as seen by military aircrafts is critical for crew safety. During low altitude operations, rotorcraft systems must be able to navigate these power lines during flight. Many of these military missions are flown at night which means the reflective bands including the visible, near infrared and short-wave infrared do not provide sufficient light. However, the emissive bands of the mid-wave infrared (MWIR) and long-wave infrared (LWIR) can be used to distinguish the location of these wires. LWIR sensors are typically used for pilotage applications. In both the LWIR and MWIR, the signal to noise depends on the wire emissivity and reflectivity as well as the ground and sky background path radiance. The signal to noise ratio is strongly dependent on the elevation of the viewing angle. In this paper, we model the signal to noise ratio as a function of elevation viewing angle using wire reflectivity and emissivity as well as MODTRAN calculations for path radiance. We also take MWIR and LWIR measurements to compare these two bands to the modelling results. We provide a summary of both model and measurements and make conclusions.
... Among these applications are homeland security, industrial imaging, banks, facility security, custom control and law enforcement. Detectors based on interband (Mercury-Cadmium-Telluride, MCT) and intersubband (quantum well infrared detectors, QWIPs) transitions have been the dominant technologies for such applications, 18 . 30 Difficulties in the epitaxial growth of MCT and low electron effective mass (∼ 0.009 m • ) resulting in large dark current due to tunneling especially at longer wavelengths 26 affect the development of multispectral cameras based on MCT. ...
We propose to utilize confocal Raman spectroscopy combined with high resolution atomic force microscopy (AFM) to access the sidewall profiles of etched and passivated small (24 µm×24 µm) focal plane array (FPA) features fabricated using LW/LWIR InAs/GaSb type-II strained layer superlattice (T2SL) detector material. Special high aspect ratio Si and GaAs AFM probes, with tip length of 13 µm and tip aperture less than 7 • , allow characterisation of the sidewall morphology. Confocal microscopy enables imaging of the sidewall profile through optical sectioning. Raman spectra measured on etched T2SL FPA single pixels enable us to quantify the non-uniformity of the mesa delineation process.
... Test structures indicate that the separate photodiodes in a two-color detector perform exactly like single-color detectors in terms of achievable R 0 A variation with wavelength at a given temperature. Large two-color FPAs are fabricated by Raytheon [185,186], Sofradir [187,188], and Selex [189]. RVS has developed two-colour, 1280 Â 720 large format MWIR/LWIR FPAs with 20 Â 20 mm unit cells [see Fig. 89(a)]. ...
... Dual-band megapixel MW/LW FPAs: (a) RVS 1280 Â 720 format HgCdTe FPAs mounted on dewar platforms (after Ref.[185]), and (b) JPL 1024 Â 1024 format QWIP FPA mounted on a 124-pin lead less chip carrier (after Ref.[190]). ...
Development of focal plane arrays started in seventies last century and has revolutionized imaging systems in the next decades. This paper presents progress in optical detector technology of focal plane arrays during the past twenty years. At the beginning of paper, emphasises are given on integrated detector assembly and cooling requirements of different types of detectors. Next, the classification of two types of detectors (photon detectors and thermal detectors) is done on the basis of their principle of operation. This topic is followed by general overview of focal plane array architectures.The main subject of paper is concentrated on describing of material systems and detectors operated in different spectral ranges. Special attention is given on recent progress in their detector technologies. Discussion is focused mainly on current and the most rapidly developing focal plane arrays including: CdZnTe detectors, AlGaN photodiodes, visible CCD and CMOS imaging systems, HgCdTe heterostructure photodiodes, quantum well AlGaAs/GaAs photoresistors, and thermal detectors. Emphasis is also given on far-infrared and sub-millimetre wave detector arrays. Finally, the outlook for near-future trends in optical detector technologies is presented.
... Data collection in separate IR bands is highly beneficial for military and civil applications involving identification of temperature differences and determination of the thermal characteristics of an object. Detectors based on interband [Mercury–Cadmium–Telluride (MCT)] and intersubband [quantum well infrared detectors (QWIPs)] transitions have been the dominant technologies for such applications [1], [2]. Difficulties in the epitaxial growth of MCT and low electron effective mass ð0:009 m o Þ resulting in large dark current due to tunneling especially at longer wavelengths [3] affect the development of multispectral cameras based on MCT. ...
We report on a dual-band [mid/long-wave infrared (MWIR and LWIR)] InAs/GaSb strained layer superlattice detector with a pBp architecture. Fifty percent cutoff wavelengths of 5 and 9 μm were obtained with diffusion-limited behavior for midwave IR absorber. At 77 K, the peak D* values were equal to 5 × 10<sup>11</sup> Jones (V<sub>b</sub> = +0.1 V, λ = 5 μm) and 2.6 × 1010 Jones (V<sub>b</sub> = -0.4 V, λ = 9 μm). The corresponding values of responsivity and quantum efficiency were 1.6 A/W and 39% (MWIR) and 1.3 A/W and 17% (LWIR).
We present an analytical and comprehensive optimization design for multilayer diffractive optical elements (MLDOEs) in infrared dual band for angular incidence. The diffraction efficiency of MLDOEs is affected by both wavelength and incident angle. Accordingly, the proposed optimization design considers comprehensive factors for its further design and evaluation. It can realize high diffraction efficiency and optimal microstructures of MLDOEs in dual band for angular incidence. By using numerical simulations, we demonstrate the modulation transfer function (MTF) at the cutoff frequency in an infrared dual-band optical system. It was found that such a design provides more accurate results, which helps achieve both higher MTF and smaller microstructure heights.
