VCSEL Array Structured Light Transmitter for Depth Mapping

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current structured light systems for three-dimensional depth mapping face challenges such as high implementation costs, difficulties in achieving ideal beam geometry, and limitations in modulating individual light bars, which restrict the use of high-resolution tracking and dense light patterns due to the use of edge-emitting lasers and diffractive designs requiring coherent Gaussian beams.

Innovation Solution

A VCSEL laser array is used, where each individual laser or group of lasers can be modulated statically or dynamically, with associated optical elements applying diffractive or refractive modulation to generate and alter structured light patterns, allowing for dynamic adjustment of the light pattern based on regions of interest and optimizing resolution and orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If edge-emitting lasers are used for structured light projection, then the system can produce light patterns, but the implementation cost increases and device size enlarges

Engineering Contradiction:
Improveimplementation costVSAvoidtransmitter size
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent changes the fundamental parameter of light emission geometry from edge-emitting (lateral) to surface-emitting (vertical) using VCSELs. This parameter change enables miniaturization of the transmitter device while maintaining structured light projection capability, directly resolving the contradiction between implementation cost and device size.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If diffractive designs requiring coherent Gaussian beams are used, then structured light patterns can be generated, but the system cannot modulate individual light bars dynamically

Engineering Contradiction:
Improvedynamic modulation capabilityVSAvoidsystem configuration flexibility
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the VCSEL array into individually addressable elements, allowing independent modulation of each light bar. This segmentation enables dynamic pattern generation and adaptation without requiring complex diffractive optical elements, resolving the contradiction between adaptability and device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic modulation capability by enabling independent control of each VCSEL element's emission characteristics. This allows real-time adaptation of structured light patterns to different tracking scenarios, achieving high versatility without fixed complex optical configurations.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If dense light patterns are projected for high-resolution tracking, then measurement precision improves, but detection performance deteriorates in high-density areas

Engineering Contradiction:
Improvetracking resolutionVSAvoiddetection performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by enabling independent modulation of individual VCSEL elements or groups, allowing optimization of light pattern density in specific regions. This provides high resolution where needed while maintaining detection performance in high-density areas through localized control.

Inventive Principle:
Principle #3Local quality

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 reduces the size of the structured light transmitter, enables precise control over the light pattern, and improves detection performance in high-density areas, allowing for more versatile and accurate three-dimensional tracking.

Implementation Method 1

The vertical-cavity surface-emitting laser, (VCSEL) is a type of semiconductor laser diode in which laser beam emission is perpendicular from the top surface

Methodology Applied
Scientific EffectLaser emission: Laser

Implementation Method 2

Each laser in the array or group of lasers being modulated together is provided with its own optical element. The optical element associated with an individual laser or group of laser is typically a diffraction element

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

The way that the pattern deforms on striking surfaces allows the vision system to calculate the depth and surface information of objects in the scene

Methodology Applied
Scientific EffectLight reflection and geometric distortion: Reflection

Data Source

PatentEP3274653B1Depth mapping with a head mounted display using stereo cameras and structured light
Publication Date: 2020.11.25 META PLATFORMS TECHNOLOGIES LLC
  • EP3274653B1 patent drawingFigure 1
  • EP3274653B1 patent drawingFigure 2A
  • EP3274653B1 patent drawingFigure 2B

AI summary

A tracking system generates a structured light pattern in a local area. The system includes an array of lasers that generate light. The array of lasers includes a plurality of lasers and an optical element. The plurality of lasers are grouped into at least two subsets of lasers, and each of the at least two subsets of lasers is independently switchable. The optical element includes a plurality of cells that are each aligned with a respective subset of the array of lasers. Each cell receives light from a corresponding laser of the array of lasers, and each cell individually applies a modulation to the received light passing through the cell to form a corresponding portion of the structured light pattern that is projected onto a local area.