Fiber-Coupled White Light Source Using Laser-Phosphor Conversion
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Solution Overview
Problem
Conventional light bulbs, such as incandescent bulbs, are inefficient due to high thermal energy dissipation, prone to failure from thermal expansion, and emit light over a broad spectrum that is not directional, while LEDs face limitations like the 'droop' phenomenon and limited spatial brightness.
Innovation Solution
A compact, high-brightness white light source is created by integrating gallium and nitrogen-based laser diodes with phosphor materials, allowing for efficient excitation and conversion of light, providing extreme directionality and high spatial brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional light bulbs are used, then they provide broad spectrum illumination, but they dissipate more than 90% of energy as thermal energy and emit light in all directions
Solution Approach 1:
The patent extracts only the useful portion of light emission by using optical elements to capture and redirect photons in specific directions, eliminating the omnidirectional waste characteristic of conventional bulbs. The optical cavity and reflectors extract and concentrate light in the desired direction while blocking unwanted emission angles.
Solution Approach 2:
The patent changes the emission parameter from omnidirectional to highly directional by introducing optical elements with specific geometric configurations. The optical cavity modifies the radiation pattern through controlled reflection and refraction, transforming the isotropic emission of conventional bulbs into anisotropic, directionally focused light.
2Reliability
If conventional light bulbs are used, then they provide omnidirectional illumination, but the filament fails due to thermal expansion and contraction
Solution Approach 1:
The patent replaces the mechanical filament-based light generation with a semiconductor LED structure that generates light through electroluminescence. This substitution eliminates the thermal expansion and contraction cycle that causes filament failure, as the solid-state structure does not rely on heated mechanical elements.
3Use of energy by moving object
If LEDs are used, then they offer high efficiency and long lifetime, but they exhibit the 'droop' phenomenon and limited spatial brightness
Solution Approach 1:
The patent nests multiple optical elements within the LED packaging structure, including micro-lenses, reflectors, and optical cavities. These nested optical components work together to extract more light from the LED chip and redirect it into specific spatial patterns, overcoming the limited extraction efficiency of conventional LED packages.
Solution Approach 2:
The patent introduces additional spatial dimensions for light control by using three-dimensional optical cavity structures and multi-layer optical elements. This dimensional approach allows light to be manipulated in multiple directions and planes, creating enhanced spatial brightness distribution that overcomes the limitations of simple planar LED emission.
4Device complexity
If conventional light bulbs are used, then they are simple in structure, but they emit light over a broad spectrum that is not perceived by the human eye
Solution Approach 1:
The patent applies local quality by using phosphor materials with specific emission characteristics positioned at particular locations within the optical system. Different phosphor layers or regions emit at different wavelengths, allowing the system to target specific portions of the spectrum that are useful for human vision while eliminating wasteful emission in other spectral regions.
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 solution enables a cost-effective, highly efficient white light source with improved directionality and brightness, overcoming the limitations of conventional bulbs and LEDs, suitable for various applications including lighting, automotive, and industrial uses.
Implementation Method 1
a laser device including a gallium and nitrogen containing material and configured as an excitation source with an output facet configured to output a laser emission with a first wavelength
Implementation Method 2
the phosphor member converts the laser emission with the first wavelength to a phosphor emission with a second wavelength that is longer than the first wavelength
Implementation Method 3
allowing for efficient excitation and conversion of light
Data Source
AI summary
A laser-based fiber-coupled white light system is provided. The system includes a laser device comprising a gallium and nitrogen containing emitting region having an output facet configured to output a laser emission with a first wavelength ranging from 385 nm to 495 nm. The system further includes a phosphor member integrated with light collimation elements. The phosphor member converts the laser emission with the first wavelength to a phosphor emission with a second wavelength in either reflective or transmissive mode and mixed partially with laser emission to produce a white light emission. The system includes a transport fiber coupled to the phosphor member via the light collimation elements to receive the white light emission and deliver the white light emission remotely to a lighthead for either directly distributing white light on road or to a leaky fiber for illumination applications by side-scattering.