STMicroelectronics VD6281 multispectral sensor

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STMicroelectronics has released a full-colour ambient light sensor (ALS) that is designed to help smartphones take better pictures and present more visually accurate data on screen displays. By simultaneously providing scene colour temperature, ultraviolet (UVA) radiation level and lighting frequency information, the VD6281 lets the camera correct white balance and enhance colour presentation, and sets appropriate exposure times for the camera to avoid flicker artefacts and eliminate banding in pictures and videos, especially in scenes lit with contemporary LED sources.

With its small form factor of 1.83 x 1 x 0.55 mm, the multispectral ambient light sensor can be integrated in bezel-free smartphones with small notches and inside smartwatches. The sensor uses high-performance, direct-deposition filter material to create six independent colour channels — red, green, blue, near-infrared, UVA and clear — for good colour-sensing capability and cutting-edge CCT (colour-correlated temperature) over a wide field-of-view of 120°, enabling assistance for white-balance algorithms even in difficult conditions.

The product has high sensitivity, allowing integration behind a cover glass, inside an optical module with another companion chip or flashLED, or through an opaque phone back cover, supporting optimal industrial design. Extracted UVA information can help the camera system determine whether the user is indoors or outdoors and assist the image colour rendering under artificial or natural light. The sensor can detect light levels as low as 1 mLux, works in less than 8 ms (one video frame at 120 fps) and consumes less than 1 mW in the ALS mode.

The device also embeds a flicker engine to detect fast artificial light variations. The sensor can detect all lighting frequencies from 50 Hz to 2 kHz with better than 3% accuracy, including PWM square signals generated by LED emissions. It can output flicker information in both analog and digital format in parallel with ALS operation. In conjunction with algorithms and host-processing, it is able to detect multiple light frequency harmonics in a scene to capture pictures or video clips without the ‘banding effect’, even in scenes with a complex mix of conventional lighting sources.