ST claims first 0.5-MP depth image sensor

STMicroelectronics has launched a new family of high-resolution 0.5-megapixel (MP) indirect time-of-flight (iToF) sensors that deliver 3D depth imaging to smartphones and other devices. The first product in the 3D family is the VD55H1  in a 4.5 mm × 4.9 mm die. Mapping 3D surfaces, this depth image sensor measures the distance to over half a million points, and objects are detected up to five meters from the sensor, which can be extended with patterned illumination, said the company.

“Indirect time-of-flight sensors, such as VD55H1, calculate the distance to objects by measuring the phase shift between the reflected signal and the emitted signal,” said ST. “This is a complementary technique to direct time of flight (dToF) sensors, which measure the time for transmitted signals to be reflected back to the sensor.”

The VD55H1 offers low power consumption, low noise, and an optimized die area, thanks to ST’s unique pixel architecture and fabrication process, leveraging in-house 40-nm stacked wafer technology. Power consumption can be reduced to less than 100 mW in some streaming modes to help extend the runtime of battery-operated devices, said ST. The average sensor power consumption is down to 80 mW.

The VD55H1 is said to be the first sensor of its type, featuring a 672 x 804 back-side illuminated (BSI) pixel array for iToF depth sensing. It can operate with a modulation frequency of 200 MHz with more than 85% demodulation contrast at 940 nm. This reduces the depth noise by a factor of two over existing sensors that typically operate around 100 MHz, said ST.

VD55H1 block diagram. Click for a larger image. (Source: STMicroelectronics)

Other features include multi-frequency operation, an advanced depth-unwrapping algorithm, low pixel noise floor, and high pixel dynamic range, which deliver higher measurement accuracy over long ranging distance. Depth accuracy is better than 1% and typical precision is 0.1% of distance. A short capture sequence supports a frame rate up to 120 fps.

ST cited a few examples where the sensor can be used. In smartphones, the depth image sensor enhances camera-system features including bokeh effect, multi-camera selection, and video segmentation and improves face-authentication with higher resolution and more accurate 3D images to protect phone unlocking, mobile payment, and smart systems with secure transactions and access control.  For robotics applications, the sensor provides high-fidelity 3D scene mapping for all target distances. It also can be used in emerging AR/VR use cases including room mapping, gaming, and 3D avatars.

The VD55H1 sensor is available for lead customers to sample. Volume production is scheduled for the second half of 2022. A consumer device reference design and complete software package are available.