OmniVision NIR image sensing achieves new quantum efficiency record

By Gina Roos, editor-in-chief

OmniVision Technologies, Inc. has launched Nyxel 2, its second generation of near-infrared (NIR) technology, first introduced in 2017, for image sensors that operate in low to no ambient light conditions. Thanks to refinements to its silicon semiconductor architectures and processes, Nyxel 2 technology claims new records in quantum efficiency (QE), providing a 25% improvement in the invisible 940-nm NIR light spectrum and a 17% increase in the barely visible 850-nm NIR wavelength over the first-generation technology.

This translates into 50% QE at 940 nm, as measured using data from a 2.9-micron pixel, and a 70% QE at 850 nm, which is on par with the QE levels of leading RGB sensors that operate in the visible light, said OmniVision. These improvements deliver greater image detection range and lower light source requirements for lower power consumption and extended battery life.

The company achieved the QE improvements by further refining its thick-silicon pixel architectures with “careful” management of wafer surface texture, together with deep trench isolation (DTI) to maintain the modulation transfer function (MTF) levels of the first generation without impacting the sensor’s dark current.

OmniVision said that these sensitivity improvements enable image sensors to see better and farther under the same amount of light to extend the image detection range. It also cuts the number of LED lights needed for Nyxel 2-based camera systems, which reduces overall power consumption and extends battery life. These improvements make the Nyxel 2 technology suited for surveillance systems, automotive in-cabin driving monitoring systems, and under-display sensors in mobile devices.

A few use-case examples cited include reducing the number of IR LEDs in security cameras to reduce power consumption and cost, or using the same number of LEDs to increase the brightness of image captures in total darkness, and increasing accuracy in automotive driver-monitoring systems while placing fewer LEDs in the cabin.

OmniVision’s first image sensors with Nyxel 2 technology are expected to be available in the second half of 2020.