Edge Emitting Laser Light Source for 3D Depth Accuracy
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Solution Overview
Problem
Current 3D camera technologies using time-of-flight methods face challenges in achieving high accuracy for distance measurement due to variations in light source characteristics with temperature changes, leading to reduced depth accuracy and increased speckle patterns.
Innovation Solution
An edge emitting laser light source with a single chip structure that incorporates multiple wavelength bands, utilizing grating regions made of materials like SiO2, SiNx, TiO2, MgF2, Al2O3, and Ta2O5, which are strategically placed between the active layer and the gain section or substrate, allowing for wavelength selection and resonance, thereby reducing temperature-dependent variations and improving depth accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wavelength light source is used in TOF method, then the device structure is simple, but temperature variations cause wavelength drift leading to reduced measurement precision
Solution Approach 1:
The light source is segmented to emit multiple discrete wavelength bands instead of a single wavelength. The edge emitting laser structure includes multiple quantum well layers that emit at different wavelengths, effectively dividing the light emission into distinct spectral segments. This segmentation allows the system to select appropriate wavelengths for different temperature conditions, maintaining measurement precision while managing device complexity.
Solution Approach 2:
The invention changes the wavelength parameter of the light source by providing multiple wavelength bands (e.g., 780nm, 830nm, 850nm, 940nm, 1310nm, 1550nm). This parameter change enables the system to adapt to temperature variations by selecting wavelengths that remain stable under different thermal conditions, thereby maintaining depth accuracy without requiring complex temperature compensation mechanisms.
2Measurement precision
If multiple wavelength bands are integrated in a single chip, then temperature-dependent wavelength variations are reduced, but the manufacturing complexity increases
Solution Approach 1:
Multiple wavelength-emitting quantum well layers are merged into a single integrated chip structure. The edge emitting laser combines multiple active layers with different composition ratios (InGaAsP layers with varying In content) to generate multiple wavelength bands from one chip. This merging approach achieves wavelength stability while managing manufacturing complexity through integrated fabrication processes.
Solution Approach 2:
The single chip structure is designed to perform multiple functions: generating multiple wavelength bands, providing wavelength selection through grating regions, and maintaining thermal stability. The universal design allows the same chip to serve as both the light source and the wavelength selector, reducing the need for separate components and simplifying the overall manufacturing process.
3Measurement precision
If grating regions are added for wavelength selection, then depth accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
The wavelength selection function is added in the spectral dimension rather than requiring additional spatial components. The grating regions are integrated within the laser cavity structure itself, using diffraction grating patterns etched into the waveguide layers to select specific wavelengths. This dimensional approach allows wavelength selection without adding bulky external components, maintaining compact device structure while improving depth accuracy.
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 provides a high accuracy 3D image obtaining apparatus with reduced temperature-dependent wavelength variations and speckle patterns, enhancing the precision and reliability of distance measurements while minimizing manufacturing costs and complexity.
Implementation Method 1
a wavelength selection section including a plurality of grating regions (35) configured to select wavelengths of light emitted from the active layer (20)
Implementation Method 2
The grating regions may be configured to select light of different wavelengths according to grating array structures of the grating regions
Implementation Method 3
a gain section (40) configured to resonate the light having the selected wavelengths in a direction parallel with the active layer (20)
Implementation Method 4
The active layer (20) may have a multi-quantum well structure
Data Source
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AI summary
An edge emitting laser light source and a three-dimensional (3D) image obtaining apparatus including the edge emitting laser light source are provided. The edge emitting laser light source includes a substrate; an active layer disposed on the substrate; a wavelength selection section comprising grating regions configured to select wavelengths of light emitted from the active layer; and a gain section configured to resonate the light having the selected wavelengths in a direction parallel with the active layer.