STMicroelectronics is enabling the next generation of intelligent machine vision applications with new high-speed image sensors that use global shutter, the optimal mode for capturing distortion-free images when the scene is moving or when near-infrared illumination is required.
The ST image sensor 's advanced process technologies enable class-leading pixel sizes while offering high sensitivity and low crosstalk. The combination of silicon process innovation with advanced pixel architecture enables the realisation of a smaller pixel array on the top array, while maintaining a larger silicon area on the bottom array to increase digital processing capabilities and functionality.
The new sensors are the VD55G0 with 640 x 600 pixels and the VD56G3 with 1.5 Mpixel (1124 x 1364). Measuring 2.6 x 2.5 mm and 3.6 x 4.3 mm respectively, the VD55G0 and VD56G3 are the smallest on the market in relation to resolution.
Low pixel-to-pixel crosstalk at all wavelengths, particularly in the near infrared, ensures high contrast for superior image clarity.
The VD56G3's integrated optical flow processing calculates motion vectors, without the need for host computer processing. These new sensors are ideal for a wide range of applications, including augmented reality and virtual reality (AR/VR), Simultaneous Localization and Mapping (SLAM) and 3D scanning.
Technical information
Global-shutter sensors save all the pixel data in each frame at once, instead of rolling-shutter technology, which captures pixel data sequentially one line at a time, making moving images vulnerable to distortion or requiring additional corrective processing.
ST's advanced pixel technology, including full Deep Trench Isolation (DTI), enables extremely small 2.61 x 2.61 μm pixels that combine low Parasitic Light Sensitivity (PLS), high Quantum Efficiency (QE) and low crosstalk in a single matrix layer, attributes that other pixel technologies cannot achieve simultaneously.
The ST approach allows a small pixel on a backside illumination (BSI) array, which enables space-saving vertical stacking of the optical sensor and associated signal processing circuitry on the lower array to achieve an extremely small sensor size and incorporate more key features, including a fully autonomous optical flow block.
The lower matrix is manufactured using ST's 40nm technology and integrates digital and analogue circuits. The high-density, low-power digital circuitry incorporates hardware features including an exposure algorithm with statistics collected from up to 336 zones, automatic defect correction and automatic dark calibration. The fully autonomous low-power optical flow block is capable of calculating 2000 motion vectors at 60 fps. Embedded vector generation is extremely useful for AR/VR and robotics, to support SLAM or six degrees of freedom (6DoF) use cases, especially in host systems with limited processing capabilities.
The sensors also support multiple frame contexts with programmable sequencing, including full lighting controls. They also feature an integrated temperature sensor, I2C Fast mode + control, defect correction, windows, binning and MIPI CSI-2 data interface.
Comments
"These new global shutter image sensors, which are based on our third generation of advanced pixel technology, deliver significant performance in terms of performance, size and system integration," said Eric Aussedat, Imaging Sub-Group General Manager and Executive Vice President of the Analog, MEMS and Sensors Group, STMicroelectronics. "They are enabling another step forward in machine vision applications, allowing designers to create tomorrow's smart and autonomous industrial and consumer devices."
