Multimode VCSEL Illumination Module for Depth Imaging
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Solution Overview
Problem
Optical imaging systems face challenges in providing uniform and versatile illumination for distance measurements and depth imaging, as existing solutions either lack homogeneity in diffuse illumination or are limited to single modes of operation.
Innovation Solution
The implementation of a multimode illumination module using VCSEL arrays with subsets of light emitting elements of different apertures and durations, allowing for independent control to achieve homogenous diffuse illumination and structured light patterns through temporal light stitching, enabling gap-free and multi-mode operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single VCSEL array is used for illumination, then the device structure is simple, but the illumination uniformity is insufficient with gaps appearing in diffuse illumination
Solution Approach 1:
The VCSEL array is divided into multiple independently controllable subsets, where each subset can be activated separately. This segmentation allows different regions of the array to contribute to filling illumination gaps at different times, achieving uniform diffuse illumination without requiring a more complex multi-array structure.
Solution Approach 2:
The system dynamically controls the activation of different VCSEL subsets based on temporal sequencing. By switching between subsets in a time-multiplexed manner, the system adapts the illumination pattern to fill gaps uniformly, transforming a static single-mode array into a dynamic multi-mode illumination source.
2Illumination intensity
If multiple VCSEL arrays are used to achieve uniform illumination, then the illumination homogeneity improves, but the device footprint increases
Solution Approach 1:
Instead of using multiple physical VCSEL arrays, the patent segments a single array into multiple independently addressable subsets. This allows the functional equivalence of multiple arrays to be achieved within the footprint of one array, maintaining illumination homogeneity while reducing the overall device area.
Solution Approach 2:
The patent transitions from a spatial solution (multiple arrays side-by-side) to a temporal solution (multiple subsets activated at different times). By adding the time dimension to the illumination control, the system achieves multi-array illumination coverage without increasing the spatial footprint.
3Adaptability or versatility
If a fixed illumination mode is used, then the system design is simple, but the versatility for different imaging applications is limited
Solution Approach 1:
The VCSEL array is designed to support multiple illumination modes (diffuse, structured light, hybrid) through software-controlled activation of different subsets. This universal design allows a single hardware configuration to perform multiple imaging functions, eliminating the need for separate dedicated arrays for each mode.
Solution Approach 2:
The illumination mode is dynamically switchable by controlling which VCSEL subsets are activated and for what duration. The system can transition between diffuse illumination, structured light patterns, and hybrid modes in real-time, providing adaptability without requiring physical reconfiguration or multiple fixed-mode arrays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the projection of more homogenous diffuse illumination with reduced gaps and the ability to switch between diffuse and structured light modes, enhancing the imaging system's capability for proximity and depth data generation with a smaller footprint.
Implementation Method 1
Each of the light emitting elements of the first subset is operable to produce a respective light beam, and each of the light emitting elements of the second subset is operable to produce a respective light beam
Data Source
AI summary
Illumination modules are operable, in some implementations, to project a homogenous diffuse illumination onto a scene. Some implementations allow different subsets of light emitting elements to be addressed independently so that they can be turned on (or off) at different times, which can facilitate multi-mode operation.