Curved Image Sensor Could Revolutionize Infrared Cameras with Far Greater Performance with Lower Cost and Size
HRL Laboratories, LLC, announced it has received an award from the Intelligence Advanced Research Projects Activity (IARPA), within the Office of the Director of National Intelligence, to develop spherically curved short-wave (SWIR) and medium wave (MWIR) infrared image sensors. This research will build on breakthrough curved visible-light image sensor technology developed at HRL. Curved image sensors have significant advantages over flat sensors in that they increase performance and reduce cost, weight, and volume of optics for many types of cameras. Curved sensor technology is poised to improve many optic-related scientific fields including photography, videography, computer vision and automation, reconnaissance and surveillance imaging, microscopy, and telescopy, among others.
“Infrared sensors and their optics have different challenges than visible light imagers,” said Geoff McKnight, HRL’s principal investigator on the project. “One of which is that they often must be operated at very low temperatures, which introduces thermal stresses from the contraction of the sensors. After curving the sensors, we will have to cool them to cryogenic temperature for operation, and the combination of the thermal stresses and bending stresses may potentially degrade or fracture the detectors.”
The goal of the 12-month program is to develop fundamental technology and gain a better understanding of the effects of the bending process on the performance of III-V semiconductor SWIR and MWIR image sensors. A part of the program will examine the benefits of curved sensors for infrared lens design. Because traditional glasses do not transmit at some infrared frequencies, different lens materials must be used. These substitute materials are much more expensive and often less durable than glass. When building a traditional visible-light camera there is a large catalog of glass types available and they can be mixed and matched to optimize optical performance. In infrared lenses, the lens material catalog is very limited, making lens design challenging.
“Because the toolkit is limited in the thermal imaging space, curved sensors may be even more value in that space than in the visible light space,” McKnight said.
The performance of the sensors is sensitive to the mechanical strain of bending, and the cooling process can affect the sensor’s performance. The HRL team will be pushing the limits of bending and cooling the material, so they will be characterizing how the bending operation changes the performance of the sensor to determine how best to use the technology.
HRL Laboratories, LLC, Malibu, California (hrl.com) is a corporate research-and-development laboratory owned by The Boeing Company and General Motors specializing in research into sensors and materials, information and systems sciences, applied electromagnetics, and microelectronics. HRL provides custom research and development and performs additional R&D contract services for its LLC member companies, the U.S. government, and other commercial companies.
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