Broadband image sensors for biomedical, security, and automotive applications

Dutta, Achyut K.; Sengupta, Rabi; Krishnan, Anupriya; Islam, Salekul; Wijewarnasuriya, P. S.; Dhar, Nibir K.

doi:10.1117/12.754495

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…Our innovations have incorporated micro-nano pillars to enhance sensitivity as well as boost the absorption spectra, which have demonstrated significant advantages over standard detectors [2] - [7]. Having developed broad spectral band Focal Plane Arrays (FPA) ranging from 350 nm to 1700 nm and extendable to 2500 nm, we have broadened our focus onto more advanced readout electronics including an advanced digital ROIC [8] to support high-performance FPAs and instituted strategies for reducing the costs of IR camera systems.…”

Section: Banpil's Development Of Low-cost High-performance Ir Camera mentioning

confidence: 99%

Strategic options towards an affordable high-performance infrared camera

et al. 2016

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The promise of infrared (IR) imaging attaining low-cost akin to CMOS sensors success has been hampered by the inability to achieve cost advantages that are necessary for crossover from military and industrial applications into the consumer and mass-scale commercial realm despite well documented advantages. Banpil Photonics is developing affordable IR cameras by adopting new strategies to speed-up the decline of the IR camera cost curve. We present a new short-wave IR (SWIR) camera; 640x512 pixel InGaAs uncooled system that is high sensitivity low noise (<50e-), high dynamic range (100 dB), high-frame rates (> 500 frames per second (FPS)) at full resolution, and low power consumption (< 1 W) in a compact system. This camera paves the way towards mass market adoption by not only demonstrating highperformance IR imaging capability value add demanded by military and industrial application, but also illuminates a path towards justifiable price points essential for consumer facing application industries such as automotive, medical, and security imaging adoption. Among the strategic options presented include new sensor manufacturing technologies that scale favorably towards automation, multi-focal plane array compatible readout electronics, and dense or ultra-small pixel pitch devices.

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Section: Banpil's Development Of Low-cost High-performance Ir Camera mentioning

confidence: 99%

Strategic options towards an affordable high-performance infrared camera

et al. 2016

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“…With the appropriate design, this gap behaves as a Fabry-Perot resonant cavity which maximizes IR absorption and hence maximizes responsivity and detectivity. The resonant cavity can be created between the incoming and reflected waves if the cavity depth is tuned accordingly: (7) where is the air gap depth, is an integer, is the wavelength, and and are the phase differences between the incoming and reflected light [36]. In operation, the microbolometer requires either current or voltage biasing.…”

Section: Background and Theorymentioning

confidence: 99%

“…These approaches are effective for certain applications, but they have proven to be bulky and costly [3]. Cooled multiband FPAs are based on mercury cadmium telluride (MCT), quantum-well IR photodetectors using III-V materials, and quantum-dot IR photodetectors [4]- [7]. These detectors offer many advantages such as high sensitivity and very high speed, but require expensive and heavy cryogenic equipment to operate.…”

Section: Introductionmentioning

confidence: 99%

Design of Dual-Band Uncooled Infrared Microbolometer

et al. 2011

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This paper describes the design and modeling of a smart uncooled infrared detector with wavelength selectivity in the long-wavelength infrared (LWIR) band. The objective is to enhance the probability of detecting and identifying objects in a scene. This design takes advantage of the smart properties of vanadium dioxide (VO 2 ): it can switch reversibly from an IR-transparent to an IR-opaque thin film when properly triggered. This optical behavior is exploited here as a smart mirror that can modify the depth of the resonant cavity between the suspended thermistor material and a patterned mirror on the substrate, thereby altering wavelength sensitivity. The thermistor material used in the simulation is vanadium oxide (VO X ). The simulation results show that, when VO 2 is used in the metallic phase, it reflects IR radiation back to the suspended VO X and enhances IR absorption in the 9.4-10.8-m band. When the film is switched to the semiconductor phase, it admits most IR radiation, which is then reflected back to the suspended VO X by a patterned gold thin film under an SiO 2 spacer layer. The spacer layer is used to increase the resonant cavity depth underneath the microbolometer pixel. Thus, the peak absorption value is shifted to 8-9.4 m, creating the second spectral band. The detector is designed with a relatively low thermal conductance of 1.71 10 7 W/K to maximize responsivity (R v ) to values as high as 1.27 10 5 W/K and detectivity (D ) to as high as 1 62 10 9 cm Hz 1 2 /W, both at 60 Hz. The corresponding thermal time constant is equal to 2.45 ms. Hence, these detectors could be used for 60-Hz frame rate applications. The extrapolated noise equivalent temperature difference is 14 and 16 mK for the 8-9.4-and 9.4-10.8-m bands, respectively. The calculated absorption coefficients in the two spectral bands were 59% and 65%, respectively.Index Terms-Dual-band infrared (IR) detector, microbolometer, vanadium oxide (VOx).

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“…In this paper, we will demonstrate a 2-dimensional p-i-n (hereafter also mentioned as PIN) array at room temperature. Based on our previous low-dark current p-i-n designs, the improvements were focused on the p-i-n device structure to minimize the surface leakage current and the junction diffusion current [4][5][6][7][8]. This photodetector has a broadband spectral response, and reduces the need for separate detectors in the range of 1 to 2 µm.…”

Section: Introductionmentioning

confidence: 99%

Development of high performance SWIR InGaAs focal plane array

et al. 2015

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Banpil Photonics has developed a novel InGaAs based photodetector array for Short-Wave Infrared (SWIR) imaging, for the most demanding security, defense, and machine vision applications. These applications require low noise from both the detector and the readout integrated circuit arrays. In order to achieve high sensitivity, it is crucial to minimize the dark current generated by the photodiode array. This enables the sensor to function in extremely low light situations, which enables it to successfully exploit the benefits of the SWIR band. In addition to minimal dark current generation, it is essential to develop photodiode arrays with higher operating temperatures. This is critical for reducing the power consumption of the device, as less energy is spent in cooling down the focal plane array (in order to reduce the dark current). We at Banpil Photonics are designing, simulating, fabricating and testing SWIR InGaAs arrays, and have achieved low dark current density at room temperature. This paper describes Banpil's development of the photodetector array. We also highlight the fabrication technique used to reduce the amount of dark current generated by the photodiode array, in particular the surface leakage current. This technique involves the deposition of strongly negatively doped semiconductor material in the area between the pixels. This process reduces the number of dangling bonds present on the edges of each pixel, which prevents electrons from being swept across the surface of the pixels. This in turn drastically reduces the amount of surface leakage current at each pixel, which is a major contributor towards the total dark current. We present the optical and electrical characterization data, as well as the analysis that illustrates the dark current mechanisms. Also highlighted are the challenges and potential opportunities for further reduction of dark current, while maintaining other parameters of the photodiode array, such as size, weight, temperature of peak performance (lowest dark current), and power consumption.

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Broadband image sensors for biomedical, security, and automotive applications

Cited by 5 publications

References 17 publications

Strategic options towards an affordable high-performance infrared camera

Strategic options towards an affordable high-performance infrared camera

Design of Dual-Band Uncooled Infrared Microbolometer

Development of high performance SWIR InGaAs focal plane array

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