New panchromatic ambient light sensor with flicker detection

STMicroelectronics has released an innovative panchromatic ambient light sensor (ALS). The new sensor, called the VD6281, allows smartphones to take better photos and present more visually accurate data on the screen. By simultaneously output field temperature, ultraviolet (UVA) radiation intensity and light frequency information, the VD6281 can help the camera correct white balance and enhance color rendering, set the appropriate exposure time for the camera, avoid flicker artifacts, and eliminate banding on photos and videos, especially in scenes with modern light sources such as leds.

Eric Aussedat, General Manager, Imaging Products, STMicroelectronics, said: "The VD6281 is a highly advanced multi-spectral ambient light sensor based on our extensive knowledge of camera systems, and our ambient light and scintillation sensor development program complement ST's market-leading FlightSense Time of Flight (ToF) portfolio. With the increasing number of high-quality, high-resolution cameras within a single phone, we are committed to providing advanced smartphone camera white balance correction assistance and flicker artifact elimination solutions. Phones equipped with VD6281 have already been released in 2018, and there will be more phones equipped with VD6281 to follow."

With a compact size of 1.83 x 1.0 x 0.55mm, the VD6281 is the smallest multi-spectral ambient light sensor on the market today and can be integrated into narrow-bezel smartphones and smartwatches where high screen proportions are valuable in the slot space. The sensor uses high performance direct deposition filter material to construct 6 independent color channels: Red, green, blue, near-infrared, UVA, and transparent deliver superior color sensing and cutting-edge CCT(Correlated color temperature) prediction in a wide Angle range of 120 degrees, helping white balance algorithms perform accurate operations even in harsh lighting conditions such as low-contrast scenes, low light, or special artificial light.

Technical description:

STMicroelectronics has developed an innovative photodiode architecture and a patented analog output device to increase sensitivity and reduce system noise while maintaining a small chip area. The VD6281 is five times more sensitive than other color sensors on the market and can be integrated with a companion chip or flash LED behind the glass cover, inside the optical module or through the hole mounted on the opaque back cover of the phone, supporting the best industrial design.

With its excellent sensitivity and noise control performance, UVA, RGB and IR synchronous sensing has been achieved. The extracted UVA information can help the camera system determine whether the user is indoors or outdoors, and assist in image color rendering in artificial or natural light scenes. The VD6281 can detect illuminance down to 1mLux, operate for less than 8ms (1 120fps video frame), and consume less than 1mW in ALS mode.

The VD6281 also incorporates patented flicker detection engine technology that detects instantaneous changes in artificial light. The sensor can detect optical frequencies from 50Hz to 2kHz, including PWM square wave signals generated by LED emission, with an accuracy of more than 3%. In addition to detecting ambient light, the VD6281 can also output flicker information in analog and digital formats. With the algorithm and the main processor, it can uniquely detect multiple optical harmonics in the scene, even in the presence of multiple traditional light sources (including tungsten lamps, halogens, neon lights, fluorescent lamps and leds). Photos or videos taken will not appear as "banding phenomena."

STMicroelectronics' VD6281 module is easy to use (6 pins), based on the I2C interface, and comes with a full software driver compatible with the Android platform, making integration fast and easy. The module package is reflow soldered, lead-free and RoHS compliant.