Image sensors for computer vision use ST’s die-stacking technology
Two high-speed image sensors released by STMicroelectronics use global shutter to capture images. Global shutter mode captures distortion-free images when the scene is moving or when near-infrared illumination is needed. This makes the sensors suitable for use in the next generation of smart computer vision applications, says ST.
Global-shutter sensors save all pixel data in each frame simultaneously, contrasting with rolling-shutter operation that captures pixel data sequentially, which makes moving images vulnerable to distortion or in need of additional corrective processing.
The company’s image sensor process technologies are claimed to enable class-leading pixel size while offering both high sensitivity and low crosstalk. The silicon process innovation and advanced pixel architecture allows a smaller sensor pixel array on the top die, while keeping more silicon area on the bottom die to increase digital-processing capabilities and features.
ST’s advanced pixel technology, including full deep trench isolation (DTI), enables extremely small 2.61 x 2.61 micron pixels that combine low parasitic light sensitivity (PLS), high quantum efficiency (QE), and low crosstalk in a single die layer.
The VD55GO sensor has 640 x 600 pixels and the VD56G3 sensor has 1.5Mpixels (1124 x 1364). The VD55GO measures 2.6 x 2.5mm and the VD56G3 measures 3.6mm x 4.3mm, making them the smallest image sensors available today, in relation to resolution, says ST.
They also have low pixel-to-pixel crosstalk at all wavelengths, specifically near-infrared, which ensures high contrast for image clarity. Embedded optical-flow processing in the VD56G3 calculates movement vectors, without the need for host computer processing.
The sensors are intended for a wide range of applications including augmented reality / virtual reality (AR/VR), simultaneous localisation and mapping (SLAM), and 3D scanning.
According to 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 computer-vision applications, empowering designers to create tomorrow’s smart, autonomous industrial and consumer devices.”
Samples are shipping now to lead customers.