VCSEL Array Mask Distance Optimization for 3D Structured Light
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Solution Overview
Problem
Existing structured light projectors for 3D imaging face challenges in achieving uniform light intensity distribution across the mask plane, which affects the quality of the projected structured light pattern and the ability to determine range parameters accurately.
Innovation Solution
A structured light projector design that minimizes the distance between the laser array and the mask, positioning them according to a non-uniformity profile of the emitters and a uniformity criterion related to light intensity distribution, using a VCSEL array and projection optics to ensure a uniform structured light pattern is projected onto an object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the distance between the laser array and the mask is reduced, then the uniformity of light intensity distribution across the mask plane is improved, but the complexity of positioning and alignment increases
Solution Approach 1:
The patent applies parameter changes by optimizing the distance between the laser array and mask based on the non-uniformity profile characteristics. By adjusting this critical parameter within a minimized range, the system achieves uniform light intensity distribution across the mask plane while accounting for the specific emitter characteristics of the VCSEL array.
Solution Approach 2:
The patent addresses local quality variations by considering the non-uniformity profile of individual emitters in the laser array. The positioning strategy accounts for local intensity variations across different regions of the mask plane, ensuring uniform illumination by compensating for emitter-specific characteristics through precise distance optimization.
2Manufacturing precision
If the distance between the laser array and the mask is minimized, then the quality of the projected structured light pattern is improved, but the sensitivity to positioning errors increases
Solution Approach 1:
The patent applies preliminary action by pre-determining the optimal distance between the laser array and mask based on the non-uniformity profile analysis. This pre-calculated positioning strategy is established before actual operation, allowing the system to achieve high pattern quality while having a defined reference point that reduces sensitivity to positioning variations during use.
3Illumination intensity
If a VCSEL array is used as the light source, then the coherence and brightness are improved, but the non-uniformity profile of individual emitters becomes more pronounced
Solution Approach 1:
The patent applies parameter changes by optimizing the distance parameter specifically for VCSEL arrays, taking into account their characteristic non-uniformity profiles. By adjusting this parameter, the system leverages the high coherence and brightness of VCSELs while compensating for their inherent emitter variations to achieve uniform illumination.
Solution Approach 2:
The patent addresses the local quality issues of VCSEL emitter non-uniformity by positioning the mask at an optimized distance that accounts for the specific spatial distribution characteristics of VCSEL arrays. This positioning strategy compensates for local intensity variations while maintaining the overall high brightness and coherence advantages of VCSEL technology.
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 configuration enhances the uniformity of the light intensity distribution, improving the quality of the projected pattern and enabling accurate determination of range parameters, suitable for 3D range finding applications.
Implementation Method 1
a laser array that includes a plurality of individual emitters
Implementation Method 2
substantially identical light divergence output
Implementation Method 3
projection optics adapted to image the structured light pattern onto an object
Implementation Method 4
reflected projected light to enable capturing of an image of the object
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A 3D imaging apparatus comprising a projector, comprising a laser array comprising a plurality of individual emitters, a mask for providing a structured light pattern, wherein a distance between the laser array and the mask is substantially minimized according to a non-uniformity profile of the plurality of individual emitters and according to a uniformity criterion related to the light intensity distribution across the mask plane, projection optics to image the structured light pattern onto an object, an imaging sensor adapted to capture an image of the object with the structured light pattern projected thereon and a processing unit adapted to process the image to determine range parameters.