Smartphone Image Sensor Makes Low Light a Non-Issue

While image sensors used in smartphones have made significant advances, conditions such as sunrise, sunset, and night with bright background lighting still present challenges. Sensor solutions provider OMNIVISION hopes to overcome those issues with its new OV50K40.

The company uses a technology called TheiaCel™, which reportedly harnesses the capabilities of lateral overflow integration capacitors (LOFIC) to provide the best-in-class single-exposure HDR, regardless of lighting conditions. The TheiaCel™-based OV50K40 50-megapixel (MP) image sensor features a 1.2-micron (µm) pixel in a 1/1.3-inch optical format with high gain and correlated multiple sampling (CMS) for optimal performance in low-light conditions.

“Traditional HDR suffers from motion artifacts, so single-exposure HDR is desirable,” said Arun Jayaseelan, senior product marketing manager, in an interview with Design News. “The 100 Db dynamic range is the highest possible for single-exposure video and sets a new bar for rear-facing smartphone main cameras.”

Jayaseelan added that while LOFIC is not new, it has been difficult to integrate into camera sensors. The LOFIC enables the sensor to provide 7.4 times higher single exposure range compared to the sensor’s non-LOFIC based predecessor.

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The OV50K40 supports 4-cell binning for 12.5MP at 120 frames per second (fps) and 60fps with HDR, with 4x sensitivity for flagship-level low-light performance. Quad phase detection (QPD) enables 2x2 phase detection autofocus (PDAF) across the sensor’s entire image array for 100% coverage, resulting in ultra-fast autofocus performance. An on-chip QPD re-mosaic enables full 50MP Bayer output, premium-quality 8K video and 2x crop-zoom functionality. The OV50K40 is built on OMNIVISION’s PureCel®Plus-S stacked-die technology, enabling high resolution with 1.2 µm pixels.

 According to Jayaseelan, the TheiaCel™ technology was originally deployed in the automotive market, and now is being applied to consumer smartphones. “We look forward to applying the TheiaCel™ technology to additional mobile image sensors as well as new markets in the future,” he said.