Programmable VCSEL Structured Light With Metasurface Speckle Coding
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Solution Overview
Problem
Traditional structured light generators for applications like facial recognition and 3D imaging face challenges due to inaccuracies in imaging quality, high manufacturing costs, and feature point matching errors caused by regular speckle patterns and complex coding algorithms, especially when the period of the DOE is less than or equal to the incident wavelength.
Innovation Solution
A programmable structured light generator is developed, comprising a laser module with a programmable controller and an individually addressable VCSEL array, a collimation module, and a metasurface module that projects a programmable structured light speckle dot matrix pattern, allowing for precise control of light spot position codes and improving calculation precision through one-to-one correspondence between light spot position codes and speckle dot matrix pattern codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional scalar diffraction theory and iterative algorithm optimization design are used to design DOE, then the design process is simplified, but when the period of the DOE is less than or equal to an incident wavelength, the imaging quality of the structured light is significantly reduced due to relatively large deviation from actual situation
Solution Approach 1:
The patent changes the fundamental design parameters and theoretical basis from scalar diffraction theory to vector diffraction theory, and from iterative algorithm optimization to direct calculation methods. This parameter change allows accurate design of sub-wavelength DOEs without iteration, resolving the contradiction between design simplicity and imaging quality.
Solution Approach 2:
The patent replaces the iterative algorithm optimization process with a direct calculation system based on vector diffraction theory. This substitution eliminates the need for repeated iterations while providing accurate results for sub-wavelength DOE design, thereby improving imaging quality without significantly increasing design complexity.
2Quantity of substance
If a single projector utilizes a randomly arranged array of several hundred VCSEL as basic encoding pattern duplicated and spliced by DOEs, then sufficient number and density of laser speckle distributions are achieved, but manufacturing costs are significantly increased
Solution Approach 1:
The patent applies local quality by designing DOEs with sub-wavelength periodic structures that locally modulate light to generate speckle patterns. Instead of using hundreds of VCSELs, the local structural variations in the DOE create the required speckle density and distribution, significantly reducing manufacturing cost while maintaining sufficient speckle quantity.
Solution Approach 2:
The patent uses DOE structures to optically copy and splice basic code patterns to generate the required speckle code pattern. This optical copying method achieves sufficient speckle distribution density without requiring physical duplication of hundreds of VCSEL components, thereby reducing manufacturing complexity and cost.
3Ease of operation
If laser speckle code pattern is formed by copying and splicing basic code patterns generated by laser random array, then the pattern can be generated, but coding and decoding algorithms become complex and similar blocks appear causing feature point matching errors
Solution Approach 1:
The patent introduces asymmetry and randomness in the speckle pattern generation through sub-wavelength DOE structures, ensuring that each speckle pattern is unique and non-repetitive. This eliminates similar blocks in the code pattern, preventing feature point matching errors and improving calculation precision while maintaining ease of operation.
Solution Approach 2:
The patent employs dynamic and flexible coding algorithms that can adapt to the speckle patterns generated by sub-wavelength DOEs. The decoding process uses correlation analysis and optimization algorithms that dynamically identify and match feature points, avoiding errors from similar blocks and improving measurement precision while maintaining operational simplicity.
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
The solution enables efficient and flexible control of speckle code patterns, significantly improving calculation precision and reliability while enabling ultra-thinness and miniaturization of the structured light generator, expanding its application range.
Implementation Method 1
a collimation module, disposed at a light outlet of the VCSEL array, wherein the collimation module is used for collimating emergent light of the VCSEL array
Implementation Method 2
a metasurface module, disposed on an emergent light focal plane path, wherein the metasurface module is used for projecting a programmable structured light speckle dot matrix pattern in a far field
Implementation Method 3
the metasurface module is used for projecting a programmable structured light speckle dot matrix pattern
Data Source
AI summary
A programmable structured light generator, a photoelectric device having same, and a manufacturing method. The structured light generator includes: a laser module, wherein the laser module includes a programmable controller and an individually addressable vertical cavity surface emitting laser array (VCSEL), and the programmable controller is used for controlling light spot position coding of the VCSEL array; a collimation module, disposed at a light source emitter of the VCSEL array, wherein the collimation module is used for collimating emergent light of the VCSEL array; and a metasurface module, disposed on an emitted light focal plane path, wherein the metasurface module is used for projecting a programmable structured light speckle dot matrix pattern in a far field.