GaN Laser Diode Illumination System for Directional Light
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Solution Overview
Problem
Conventional light bulbs, such as Edison bulbs and other discharge lamps, face issues like high energy dissipation, filament failure due to thermal expansion, broad and non-ideal spectral emission, and lack of directionality, while solid-state lighting, like LEDs, has limitations in spatial brightness and droop phenomenon, making them unsuitable for all lighting applications.
Innovation Solution
A dual-band light source system integrating gallium and nitrogen containing laser diodes capable of emitting both visible and infrared light, using a process to transfer gallium and nitrogen layers, with sensors for feedback loops to activate illumination sources, enabling applications like smart lighting, LiFi, and LIDAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional light bulbs are used, then they provide omnidirectional illumination, but they dissipate more than 90% of energy as thermal energy and emit light over a broad spectrum much of which is not perceived by the human eye
Solution Approach 1:
The patent transitions from thermal radiation (incandescent) to electroluminescence (LED) and stimulated emission (laser), fundamentally changing the energy conversion mechanism. This parameter change in the emission process eliminates the 90% thermal energy waste, achieving over 50% electrical-to-optical conversion efficiency while maintaining or improving perceived illumination intensity.
Solution Approach 2:
The patent employs wavelength-selective phosphor conversion layers that selectively convert specific portions of the laser spectrum to visible wavelengths. This local quality approach ensures that energy is converted only where needed (specific wavelength bands), minimizing waste and maximizing perceived light output in the human-visible spectrum.
2Ease of operation
If conventional light bulbs are used, then they emit light in all directions, but this lack of directionality is undesirable for applications requiring strong directionality or focus
Solution Approach 1:
The patent segments the illumination function into two distinct components: a highly directional laser source for focused applications and omnidirectional LED components for general illumination. This segmentation allows each component to optimize its emission pattern for its specific function, with the laser providing strong directionality when needed.
Solution Approach 2:
The patent introduces optical shaping elements that manipulate the spatial distribution of light in multiple dimensions. These elements transform the inherently directional laser beam into controllable patterns, adding dimensional control over the illumination geometry without sacrificing the underlying directionality advantage.
3Loss of energy
If solid state lighting like LEDs are used, then they offer high efficiency and long lifetimes, but they suffer from spatial brightness limitations and the droop phenomenon
Solution Approach 1:
The patent merges the advantages of three different light sources: the high energy efficiency of LEDs, the long lifetime of solid-state devices, and the high spatial brightness and directed emission of lasers. By combining these technologies in a hybrid system, the patent achieves high efficiency and long lifetime while overcoming the spatial brightness limitation of pure LED solutions.
Solution Approach 2:
The patent creates a multi-functional illumination system that can operate in different modes depending on application requirements. The system can function as a high-efficiency general illumination source using LEDs, switch to high-brightness directed illumination using the laser, or combine both modes simultaneously, providing universal applicability across different lighting scenarios.
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 system provides efficient, directional, and high-brightness illumination with the ability to operate in both visible and infrared spectrums, addressing the limitations of conventional lighting technologies and enhancing applications in various fields including defense, communication, and horticulture.
Implementation Method 1
The first pump-light device includes a gallium and nitrogen containing laser diode having an optical cavity with an optical waveguide region... configured to output first directional electromagnetic radiation... characterized by a first peak wavelength
Implementation Method 2
a wavelength converter... configured to convert at least a fraction of the first directional electromagnetic radiation... to a second wavelength that is longer than the first wavelength and to output a visible light emission
Implementation Method 3
an infrared emitting laser diode... configured to output a third directional electromagnetic radiation... characterized by a third peak wavelength in the infrared portion of the electromagnetic spectrum
Data Source
AI summary
A light source or system configured to emit visible white light and infrared emissions includes a laser diode, a wavelength converter, and an infrared emitting laser diode.