Programmable Optical Projector Using Multiple Beam Grating
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Solution Overview
Problem
Existing optical projection systems for 3D surface measurements and motion detection, such as those using VCSEL arrays, face challenges with heating effects and complexity in manufacturing, particularly when requiring custom, irregular laser arrays for higher power and longer distances.
Innovation Solution
An optical projector design featuring a laser array with at least one multiple beam grating (MBG) that duplicates and rotates the light pattern, allowing for nearly unlimited patterns and independent laser excitation, using either fixed or rotating MBGs, and allowing for the use of larger, more powerful lasers arranged in a regular or irregular pattern on a substrate or PC board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VCSEL arrays are used for optical projection, then depth detection capability is improved, but heating effects and manufacturing complexity increase
Solution Approach 1:
The patent divides the laser array into multiple independently controllable groups or subsets. Instead of requiring all lasers to be perfectly uniform, the system segments the array so that different groups can be selectively activated. This segmentation allows the use of standard, easier-to-manufacture laser components while maintaining depth detection capability through controlled activation of specific subsets.
Solution Approach 2:
The patent introduces temporal dynamics by selectively activating different subsets of lasers at different time intervals. The system dynamically switches between different laser subsets, allowing each subset to be optimized for specific functions. This dynamic activation pattern enables the system to achieve high measurement precision while using simpler, more manufacturable laser components.
2Length of stationary object
If higher power lasers are used for longer distances, then projection distance is improved, but heating effects increase
Solution Approach 1:
The patent employs periodic activation of laser subsets rather than continuous operation of all lasers. By cycling through different subsets in a periodic manner, the system achieves the necessary total optical power for long-distance projection while allowing each individual laser to rest and cool down during periods when other subsets are active. This periodic action pattern reduces cumulative heating effects while maintaining projection distance capability.
Solution Approach 2:
The patent activates only the necessary subset of lasers at any given time rather than all lasers simultaneously. This partial action approach provides sufficient optical power for the required projection distance while leaving other lasers inactive, thereby reducing overall heat generation in the array.
3Adaptability or versatility
If custom irregular laser arrays are used, then pattern uniqueness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses standard, regularly-spaced laser arrays that can serve multiple functions through selective activation. The same regular array structure can generate different effective patterns by activating different subsets of lasers in different temporal sequences. This universality allows the system to achieve pattern uniqueness and adaptability without requiring custom-manufactured irregular arrays, thereby simplifying manufacturing.
Solution Approach 2:
The patent achieves pattern uniqueness by dynamically changing operational parameters (which subset of lasers is active, activation timing, duty cycles) rather than changing the physical spatial arrangement of the lasers. This parameter-based approach to pattern generation maintains manufacturing simplicity while providing the necessary pattern uniqueness for depth detection.
4Illumination intensity
If all lasers are excited simultaneously, then pattern brightness is improved, but heating effects increase
Solution Approach 1:
The patent maintains continuous projection of the light pattern by seamlessly switching between different laser subsets. While individual lasers are activated and deactivated to reduce heating, the overall pattern projection continues uninterrupted through the coordinated activation of multiple subsets. This continuity of useful action ensures sustained pattern brightness while managing thermal loads through temporal distribution of activation.
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 solution enhances depth perception and motion detection capabilities, simplifies manufacturing, and provides flexible pattern generation for various applications like self-driving systems and facial recognition, while reducing the risk of defective lasers and heating issues.
Implementation Method 1
At least one multiple beam grating (MBG) is placed in front of the laser array. The light pattern from the laser array is duplicated by the MBG, and cast on an object to be measured.
Data Source
AI summary
In an embodiment, an optical projector is provided with a laser array. Each laser is either collimated or focused to a fixed distance. At least one multiple beam grating (MBG) is placed in front of the laser array. The light pattern from the laser array is duplicated by the MBG, and cast on an object to be measured. The pattern on the object is changed by rotating the MBG. As a result, the number of patterns of structured dots that can be projected on the object is nearly unlimited. The optical projector can be used to provide depth perception to motion detection systems, to vehicle self-driving systems, and for many other uses.