Latest pixel size reduction of uncooled IR-FPA at CEA, LETI

Becker, S.; Imperinetti, P.; Yon, Jean-Jacques; Ouvrier-Buffet, Jean-Louis; Goudon, V.; Hamelin, A.; Vialle, C.; Arnaud, A.

doi:10.1117/12.974579

Cited by 17 publications

(10 citation statements)

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“…With a QVGA format detector with 12µm pixel pitch [1], one can expect a minimum horizontal field of view (HFOV) of 35.5°, and with a QVGA format detector with 10µm pixel pitch, one can expect a minimum horizontal field of view (HFOV) of 29.9°. Low-cost thermal lens designs are either a reverse lens [6] or a two-lens group [7] [8].…”

Section: Design Strategies For Infrared Lenses Compatible With Wafer-...mentioning

confidence: 99%

Study of an infrared hybrid chalcogenide silicon lenses compatible with wafer-level manufacturing process for automotive applications

Druart

Barrière

Volatier

et al. 2021

Optical Design and Engineering VIII

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Infrared cameras could serve automotive applications by delivering breakthrough perception systems for both in-cabin passengers monitoring and car surrounding. However, low-cost and high-throughput manufacturing methods are essential to sustain the growth in thermal imaging markets for automotive applications, and for other close-to-consumer applications which have a fast growth potential. Fast low cost infrared lenses suitable for microbolometers are currently already sold by companies like Umicore, Lightpath, FLIR… They are either made of a single inverse meniscus Chalcogenide glass or of two Silicon optics. In this paper, we explore hybrid systems with a large field of view around 40° combining Chalcogenide and Silicon in order to take advantage of both materials. Both are compatible with wafer-level process. Silicon optics can be manufactured by photolithography process and are expected to be more cost-effective than Chalcogenide ones. However they are constrained in shape and sag height. On the other hand, Chalcogenide optics can be collectively molded and could have more free shapes. They are thus more suitable to reach high-demanding performance. So hybrid designs could be seen as a compromise between cost and performance. In this paper, we show that fast lenses with diameter constraints to few millimeters to make affordable wafer-level process lead to small size detectors. As a consequence, the pixel pitch reduction of microbolometers is a key point to maintain a good resolution. Finally, strategies to improve the production yield of hybrid lenses are explored.

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Section: Design Strategies For Infrared Lenses Compatible With Wafer-...mentioning

confidence: 99%

Study of an infrared hybrid chalcogenide silicon lenses compatible with wafer-level manufacturing process for automotive applications

Druart

Barrière

Volatier

et al. 2021

Optical Design and Engineering VIII

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“…In 2012, DARPA founded three contracts to develop sub $500 thermal imaging camera with 12 µm pixels. At the same time, LYNRED with CEA released IR FPAs with 12µm pixel pitch [1]. Nowadays, IR FPAs with 10µm pixel pitch can be found [2].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the potential of high index chalcogenide lenses for automotive applications

Druart

Reux

Calvez

et al. 2022

Advanced Optics for Imaging Applications: UV Through LWIR VII

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Infrared cameras could serve automotive applications by delivering breakthrough perception systems for both in-cabin passengers monitoring and car surrounding. However, low-cost and high-throughput manufacturing methods are essential to sustain the growth in thermal imaging markets for automotive applications, and for other close-to-consumer applications, which have a fast growth potential. With the reduction of the pixel pitch of microbolometer detectors, their cost has decreased considerably and now the optical part represents a significant part of the system cost. Fast low cost infrared lenses suitable for microbolometers are already sold by companies like Umicore, Lightpath, FLIR… Chalcogenide glasses are widely used as materials for optics because they have many cost advantages, especially due to the possibility of mass molding the optics. However, with the reduction of the pixel pitch, it is more and more difficult to design high performance lenses with a limited number of optics. The possibility of molding the optics allows us to use many highly aspherical surfaces at affordable costs. However, Chalcogenide glasses have usually a lower refractive index than other more expensive infrared materials such as Germanium. Indeed, high refractive index materials are known to be effective in attenuating the amplitude of many geometric aberrations. In this presentation, we evaluate the interest of high index Chalcogenide lenses, especially TGG and TGS, to design optical systems meeting the needs of the automobile with a limited number of optics. TGG glass has an index of refraction of 3.396 at a wavelength of 10µm, i.e. its index of refraction is close to the Silicon one and was initially studied for space applications. TGS has a lower index of refraction (3.12@10µm) but can be used in a cost effective manufacturing process by using flash spark plasma sintering (SPS) on raw powder. Demonstrators with TGG glass have been made and their performance evaluated.

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“…(3,5), the change rate of thermal resistance due to the incident power or selfheating effect can be extract. If the bias voltage is applied, the thermal conductance is decreased as much as the SHF/G, and the thermal resistance (R th ) is increased by the SHF×R th .…”

Section: Parameter Extraction For An Electro-thermal Modelingmentioning

confidence: 99%

“…The infrared (IR) image sensors based on uncooled microbolometer focal plane array (MFPA) have successfully been commercialized in many areas, including medicine, surveillance, mobile, military, night vision applications [1][2][3][4]. Microbolometer cells are resistive sensors that are sensitive to IR radiation.…”

Section: Introductionmentioning

confidence: 99%

Electro-Thermal Modeling and Experimental Validation of Integrated Microbolometer with ROIC

Kim¹,

Kim²,

Kim³

et al. 2016

JSTS:Journal of Semiconductor Technology and Science

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Abstract-This paper presents an electro-thermal modeling of an amorphous silicon (a-Si) uncooled microbolometer.This modeling provides a comprehensive solution for simulating the electrothermal characteristics of the fabricated microbolometer and enables electro-thermal cosimulation between MEMS and CMOS integrated circuits. To validate this model, three types of uncooled microbolometers were fabricated using a post-CMOS surface micromachining process. The simulation results show a maximum discrepancy of 2.6% relative to the experimental results.

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Latest pixel size reduction of uncooled IR-FPA at CEA, LETI

Cited by 17 publications

References 0 publications

Study of an infrared hybrid chalcogenide silicon lenses compatible with wafer-level manufacturing process for automotive applications

Study of an infrared hybrid chalcogenide silicon lenses compatible with wafer-level manufacturing process for automotive applications

Evaluation of the potential of high index chalcogenide lenses for automotive applications

Electro-Thermal Modeling and Experimental Validation of Integrated Microbolometer with ROIC

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