Laser Diode Waveguide Structure for Eye Safety
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Solution Overview
Problem
Existing light sources, such as flash lights and super-luminescent diodes, face challenges in achieving high efficiency and eye safety simultaneously, with laser diodes providing high efficiency but inadequate eye safety, and combining laser diodes with lenses or diffusers compromises efficiency and increases costs and complexity.
Innovation Solution
Designing a laser diode with a high vertical and lateral far-field divergence greater than 50°, achieved by optimizing the layer structure of waveguide and cladding layers to ensure 95% radiation emission at a specific angle, thereby enhancing eye safety without additional components like lenses or diffusers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional laser diodes are used, then high efficiency is achieved, but eye safety is insufficient due to low far-field divergence
Solution Approach 1:
The patent changes the optical parameters of the laser diode by optimizing the waveguide layer thickness (dwL between 0.01-1.0 μm) and refractive index difference (Δn ≥ 0.04) to achieve high far-field divergence (>50°) while maintaining high efficiency, eliminating the need for additional safety components
2Object-affected harmful factors
If lenses or diffusers are added to improve eye safety, then eye safety is enhanced, but efficiency is reduced and device complexity increases
Solution Approach 1:
The patent extracts the eye safety function from separate components (lenses, diffusers) and integrates it directly into the laser diode's waveguide structure, eliminating the need for additional components that would reduce efficiency and increase complexity
Solution Approach 2:
The patent merges the eye safety function with the laser diode's existing waveguide structure by optimizing layer thickness and refractive index, combining multiple functions into a single integrated component rather than using separate safety devices
3Object-affected harmful factors
If lenses or diffusers are added to improve eye safety, then eye safety is enhanced, but manufacturing cost and assembly complexity increase
Solution Approach 1:
The patent removes the need for separate safety components by extracting the eye safety function and implementing it through optimized waveguide layer parameters, simplifying the overall device structure and assembly process
Solution Approach 2:
The patent makes the waveguide structure multi-functional by designing it to simultaneously provide laser guidance and ensure eye safety through high far-field divergence, eliminating the need for dedicated safety components
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 approach results in a cost-effective, easy-to-assemble light source that balances high efficiency and eye safety, making it suitable for applications like cosmetic treatments without the need for extra safety measures.
Implementation Method 1
a first waveguide layer is provided on a first side of the active layer, a first cladding layer is provided on the first waveguide layer, a second waveguide layer is provided on a second side of the active layer, and a second cladding layer is provided on the second waveguide layer
Implementation Method 2
the conditions 0.01 μm≦dwL≦1.0 μm and Δn≧0.04 are met, where dwL is the sum total of the layer thickness of the first waveguide layer, the layer thickness of the active layer, and the layer thickness of the second waveguide layer, and Δn is a maximum of the refractive index difference between the first cladding layer and the first waveguide layer, and the refractive index difference between the second waveguide layer and the second cladding layer
Implementation Method 3
a reflection facet for reflecting the radiation emitted from the active layer and an emission facet for partial reflection and partial feed-out of the radiation emitted from the active layer are provided
Data Source
AI summary
It is the object of the present invention to specify a light source with high efficiency and high eye safety at the same time.For this purpose, the active layer (10), the first cladding layer (14), the first waveguide layer (12), the second waveguide layer (16), and the second cladding layer (18) should be designed such that 0.01 μm≦dwL≦1.0 μm and Δn≧0.04, where dwL is the sum total of the layer thickness of the first waveguide layer (12), the layer thickness of the active layer (10), and the layer thickness of the second waveguide layer (16) and Δn is a maximum of the refractive index difference between the first cladding layer (14) and the first waveguide layer (12) and the refractive index difference between the second waveguide layer (16) and the second cladding layer (18).