Eye-Safe Light Source With Perpendicular Wire Orientation
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Solution Overview
Problem
Eye-safe light sources face issues with decreased light emission efficiency and non-uniform light distribution due to multiple light scattering and wire shadows, leading to suboptimal power consumption and eye safety concerns.
Innovation Solution
The design includes a semiconductor laser emitting light parallel to a substrate reference surface with a reflection surface and wires oriented perpendicularly to the light emission direction, increasing optical path length and avoiding shadows, while maintaining polarization characteristics through controlled light scattering or reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If laser light is transmitted through a light scattering layer to increase spot diameter and make it eye-safe, then eye safety is improved, but light emission efficiency decreases due to multiple light scattering and absorption
Solution Approach 1:
The patent changes the orientation of the wire from parallel to perpendicular relative to the light emission direction, effectively using a dimensional change in spatial arrangement to eliminate the shadow effect and improve light extraction efficiency while maintaining eye safety through the scattering layer
2Reliability
If a wire is connected to the semiconductor laser, then electrical connection is achieved, but light emission efficiency decreases due to wire shadow blocking the light path
Solution Approach 1:
The wire is repositioned from a parallel orientation to a perpendicular orientation relative to the light emission direction, utilizing a dimensional change in spatial arrangement to eliminate the shadow effect while maintaining electrical connectivity
3Device complexity
If the semiconductor laser is joined to a substrate without a submount, then device complexity is reduced, but light emission efficiency decreases because the substrate blocks the spreading laser light
Solution Approach 1:
The laser is oriented to emit light parallel to the substrate surface rather than perpendicular to it, using a dimensional change in emission direction to allow light to spread laterally without being blocked by the substrate, thereby improving light extraction efficiency while maintaining direct mounting
4Strength
If the semiconductor laser is joined on the inner side of the submount, then mechanical support is improved, but light emission efficiency decreases due to submount shadow blocking the light path
Solution Approach 1:
The laser emission direction is changed from perpendicular to parallel relative to the substrate surface, using a dimensional change in orientation to eliminate the shadow effect caused by the submount while maintaining mechanical support through proper mounting configuration
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 configuration enhances light emission efficiency, regulates light distribution, and ensures eye safety by reducing light density and maintaining polarization, suitable for applications like biometric authentication.
Implementation Method 1
The substrate includes a reflection surface that faces the light emission end surface and reflects the laser light
Data Source
AI summary
Light emission efficiency is increased in an eye-safe light source by regulating light distribution properties. An eye-safe light source includes a package, a semiconductor laser that emits laser light from a left light emission end surface and a right light emission end surface, and a wire that is joined to the semiconductor laser. The semiconductor laser is joined to the package such that the laser light is emitted parallel to an upper surface of a lead frame of the package. The package includes reflection surfaces that face the left light emission end surface and the right light emission end surface and reflect the laser light. In top view, a direction in which the wire extends is perpendicular to a direction of emission of the laser light.