VCSEL Array DOE for Uncorrelated Structured Light

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Solution Overview

Problem

Depth cameras embedded in mobile terminals face challenges in projecting highly uncorrelated structured light patterns, leading to low precision in depth image calculation due to the use of edge laser emitters, which are difficult to miniaturize and require low power consumption.

Innovation Solution

A structured light projection module comprising a VCSEL array light source chip, a lens, and a diffractive optical element (DOE) that projects light patterns periodically arranged in two non-perpendicular directions, enhancing the uncorrelation and precision of spot patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If edge laser emitters are used in depth cameras, then the device can project structured light patterns, but the device size and power consumption cannot be reduced

Engineering Contradiction:

Improvepower consumptionVSAvoidprojection precision

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the fundamental parameters of the light source system by transitioning from edge laser emitters to VCSEL array with non-perpendicular periodic arrangement. This parameter change enables both reduced power consumption and maintained projection precision through the optimized geometric configuration of the light source array.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If VCSEL array light source is used, then device size and power consumption are reduced, but the ability to project highly uncorrelated structured light patterns deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoiddepth image calculation precision

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by arranging the VCSEL array in a non-perpendicular periodic configuration rather than a conventional orthogonal grid. This asymmetric arrangement creates highly uncorrelated structured light patterns that maintain depth image calculation precision while enabling the use of energy-efficient VCSEL light sources.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent introduces a new dimensional arrangement by using non-perpendicular periodic positioning of the VCSEL array elements. This dimensional change in the spatial configuration creates unique uncorrelated patterns that resolve the limitation of VCSEL-based systems while maintaining compact size and low power consumption.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If conventional perpendicular periodic arrangement is used, then manufacturing is simplified, but the uncorrelation of spot patterns is reduced

Engineering Contradiction:

ImproveDOE manufacturingVSAvoidspot pattern uncorrelation

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent deliberately introduces asymmetry in the periodic arrangement of the VCSEL array by using non-perpendicular angles. This asymmetric configuration enhances spot pattern uncorrelation for improved measurement precision while the periodic nature of the arrangement keeps the DOE manufacturing process relatively simple and scalable.

Inventive Principle:

Principle #4Asymmetry

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 improves the precision of depth image calculation by projecting highly uncorrelated spot patterns, addressing the limitations of conventional depth cameras in mobile terminals regarding size and power consumption.

Implementation Method 1

a light source array, formed by a plurality of sub-light sources arranged in a two-dimensional pattern, and emitting a two-dimensional pattern beam

Methodology Applied

Scientific EffectLight emission: Laser

Implementation Method 2

a diffractive optical element, configured to receive the two-dimensional pattern beam and diffract a structured light pattern beam outwardly

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS11237404B2Structured light projection module for projecting unrelated patterns

Publication Date: 2022.02.01 SHENZHEN ORBBEC CO LTD

AI summary

A diffractive optical element is configured to receive a first patterned light beams, and diffracts the first patterned light beams to project a second patterned light beam outwardly. The second patterned light beam is formed of combined arrangement of a plurality of first patterned light beams, and the combined arrangement includes periodic arrangement in a first direction and a second direction. The first direction and the second direction are not perpendicular to each other. By designing the performance of the diffractive optical element, the outwardly projected structured light pattern is periodically arranged in two directions, and the two directions are not perpendicular to each other, such that spot patterns are highly unrelated in multiple directions, improving accuracy.