Structured Light Module Using Multiple Light Sources and Single DOE

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Solution Overview

Problem

Existing structured light modules face a trade-off between increasing the complexity and density of projected patterns, which enhances 3D depth estimation accuracy, but this often results in reduced energy per pattern, compromising accuracy due to power limitations.

Innovation Solution

A structured light module comprising multiple light sources emitting invisible light to a single diffractive optical element (DOE) with a pseudo-random optical pattern groove, where the light is spectrally encoded and superimposed to create an overall structured light with higher density and complexity, avoiding the need for increased DOE pattern density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of patterns on the DOE is increased to increase structured light density, then the density of generated structured light increases, but the energy per pattern decreases

Engineering Contradiction:
Improvenumber of patternsVSAvoidenergy per pattern
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple light sources (first light source and second light source) to illuminate the same DOE simultaneously. Their structured light patterns are superimposed on the target object, effectively increasing the total number of patterns without requiring additional DOE complexity. This merging approach maintains sufficient energy per pattern while achieving higher overall pattern density through additive combination of multiple light sources.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If the density of patterns on the DOE is increased, then the complexity of generated structured light increases, but the energy per pattern is reduced

Engineering Contradiction:
Improvecomplexity of structured light patternVSAvoidenergy per pattern
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent segments the structured light generation function across multiple light sources rather than concentrating all complexity in a single DOE pattern set. Each light source generates its own structured light pattern independently, and these segmented patterns are then combined at the target. This segmentation allows each light source to maintain adequate energy levels while the overall system achieves higher complexity through combination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structured light system by combining light from multiple sources with different characteristics. The first and second light sources may have different wavelengths or temporal characteristics, creating a composite illumination that achieves higher effective pattern complexity without sacrificing energy distribution, as each component contributes differently to the overall pattern structure.

Inventive Principle:
Principle #40Composite materials

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 enables more accurate 3D depth estimation by increasing the complexity and density of pattern features in the projected structured light without reducing energy per pattern, thus improving the accuracy of depth sensing.

Implementation Method 1

a single diffractive optical element (DOE) with a pseudo-random optical pattern groove, where the light is spectrally encoded

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

the invisible light of each light source passes through the DOE and emits a beam of spectral encoded structured light

Methodology Applied
Scientific EffectSpectral encoding: Dispersion (of waves)

Data Source

PatentEP3680810B1Vertical cavity surface light-emitting laser, structured light module, and light projection method and terminal
Publication Date: 2023.06.07 SHENZHEN GOODIX TECH CO LTD
  • EP3680810B1 patent drawingFigure 1
  • EP3680810B1 patent drawingFigure 2A~2B
  • EP3680810B1 patent drawingFigure 2C

AI summary

The present disclosure provides a vertical-cavity surface-emitting laser, structured light module, terminal comprising the structured light module, and method for projecting the structured light thereof. The structured light module includes a plurality of light sources and a single diffractive optical element (DOE); wherein the plurality of light sources simultaneously emit a plurality beams of invisible light to the single DOE, wherein the single DOE has a pseudo-random optical pattern groove, wherein the invisible light of each light source passes through the DOE and emits a beam of spectral encoded structured light , and the beam of structured light comprises a pattern corresponding to the pseudo-random optical pattern groove. The DOE projects an overall structured light that is formed by superimposing a plurality of beams of structured light, and there is an offset between patterns of different beams of structured light.