VCSEL Array Inhomogeneous Emitter Distribution for Beam Profile Flattening
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Solution Overview
Problem
Conventional homogeneous emitter arrays in 3D sensing applications exhibit non-uniform beam profiles with areas of high and low energy intensity, leading to decreased accuracy and potential eye-safety issues due to the incoherent sum of individual emitter beams beyond the Rayleigh distance.
Innovation Solution
An emitter array with inhomogeneous emitters is designed, where subsets of emitters have different orientations and configurations to overlap areas of high and low energy intensity, resulting in a more uniform beam profile and reduced energy intensity differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If homogeneous emitter arrays are used, then manufacturing is simplified, but beam profile uniformity deteriorates with non-uniform energy distribution
Solution Approach 1:
The patent applies local quality by varying the orientation and configuration of individual emitters within the array. Specifically, different subsets of emitters are oriented at different angles (e.g., 0 degrees, 45 degrees, 90 degrees, 135 degrees) relative to the array normal, and different emitters have different active region configurations. This local variation in emitter properties compensates for the non-uniform energy distribution in the far field, achieving a more uniform beam profile while maintaining manufacturing feasibility through standardized emitter designs.
2Device complexity
If homogeneous emitter arrays are used, then device complexity is reduced, but imaging quality deteriorates due to hot spots and dark spots
Solution Approach 1:
The patent implements local quality by configuring different emitters with specific orientations and active region patterns tailored to their positions in the array. This localized customization of emitter properties ensures that energy is distributed more uniformly across the imaging area, eliminating hot spots and dark spots that would otherwise degrade 3D sensing quality. The approach maintains reasonable device complexity by using a finite set of standardized emitter configurations.
Solution Approach 2:
The patent applies asymmetry by intentionally introducing non-uniformity in emitter orientations and configurations across the array. Rather than using identical symmetric emitter arrangements, the system employs asymmetric configurations where emitters are oriented at various angles and have different active region geometries. This asymmetric arrangement is designed to produce a symmetric, uniform beam profile in the far field, effectively compensating for the inherent non-uniformity of individual emitter patterns.
3Manufacturing precision
If homogeneous emitter arrays are used, then manufacturing precision requirements are lowered, but eye safety compliance deteriorates due to high energy concentration
Solution Approach 1:
The patent applies local quality by varying emitter orientations and configurations across the array to distribute energy more uniformly. This localized variation prevents excessive energy concentration in specific directions, thereby reducing the risk of eye safety violations. The approach achieves eye safety compliance without imposing overly stringent manufacturing precision requirements, as each emitter type can be fabricated using standard processes.
Data Source
AI summary
A vertical cavity surface emitting laser (VCSEL) array may comprise a first subset of VCSELs of a plurality of VCSELs, and a second subset of VCSELs of the plurality of VCSELs. One or more first beams to be emitted by the first subset of VCSELs, when the VCSEL array is powered, and one or more second beams to be emitted by the second subset of VCSELs, when the VCSEL array is powered, may have different patterns of areas of energy intensity. The different patterns of areas of energy intensity may include respective areas of high energy intensity and respective areas of low energy intensity.