US20260235731
2026-08-13
Physics
G01S7/4814
An innovative optical illumination system is designed for Time-of-Flight (ToF) imaging devices, which are used to determine distances to objects. This system features a unique configuration involving unpolarized light sources, liquid crystal (LC) gratings, and active retarders. It is capable of switching between spot and flood illumination modes, enabling it to efficiently create different illumination patterns on an object's surface. The use of LC lenses further enhances the system by generating an adjustable illumination field, which is crucial for accurate distance measurement.
The system utilizes at least two spatially-separated LC gratings to divide light into multiple components with orthogonal circular polarizations. These components are then redirected to active retarders, which can alter the light's polarization state and switch between illumination modes. The spot illumination mode generates a pattern of point illumination spots, while the flood illumination mode creates a continuous illuminated area. LC lenses, positioned after the retarders, have varying optical powers for each light component, contributing to the system's adaptability in different modes.
Time-of-Flight imaging technology is widely applicable in fields such as computer vision, robotics, industrial automation, and various reality devices. The ability to accurately measure distance through ToF imaging is essential for these technologies. The proposed system enhances the range and flexibility of ToF devices by allowing seamless switching between illumination modes, thus improving the accuracy and reliability of distance measurements across different environments and distances.
Previous ToF systems faced limitations such as non-compact designs, high costs, and mechanical switching requirements. These systems often required separate channels for different illumination modes, leading to increased complexity and reduced efficiency. The new system addresses these issues by integrating components that allow for electronic switching and polarization control, reducing the need for mechanical parts and enhancing operational reliability.
The system stands out from prior solutions by eliminating mechanical switching and employing a single light source module for both illumination modes. This reduces bulkiness and simplifies the design. Unlike previous designs that suffered from low brightness and limited measurement ranges, this system's use of LC elements and polarization control ensures high brightness and a broad range of distance measurements. By overcoming these challenges, the system offers a more compact, cost-effective, and efficient solution for ToF imaging applications.