Laser-Excited Phosphor Capsule Collimation via Concave Mirror
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Solution Overview
Problem
Current lighting sources, such as LEDs and traditional lasers, face inefficiencies in producing full-spectrum white light and achieving high collimation due to their narrow-band emission patterns and planar configurations, limiting their use in applications requiring precise light control and full-spectral representation.
Innovation Solution
A lighting apparatus and method utilizing a laser module to generate coherent light, which is directed onto a phosphor capsule located at the focus of a concave mirror, causing the phosphor to phosphoresce and project light that is then steered and collimated by the mirror, potentially combining multiple laser-phosphor combinations to achieve a broader visible spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used as light sources, then electrical energy conversion efficiency is improved (about 80%), but the emission band is narrow (about 10 nm at half height) making full spectrum white light impractical
Solution Approach 1:
The patent combines multiple LED emitters with different emission wavelengths and phosphor materials to create a unified light source that achieves full-spectrum white light output. By merging several narrow-band LED sources (each covering different wavelength ranges) with corresponding phosphors, the system synthesizes a broad spectral output while maintaining high electrical-to-optical conversion efficiency characteristic of LEDs.
2Adaptability or versatility
If LED/phosphor combinations are used to approximate white light, then full spectrum coverage is improved, but the spectral output profile exhibits gaps in green and red bands
Solution Approach 1:
The patent applies local quality by selecting specific phosphor materials with tailored emission characteristics for each wavelength region. Different phosphors are chosen to fill specific spectral gaps - for example, using phosphors that emit strongly in the green and red regions where LED-only sources are deficient. This localized optimization of phosphor selection across different spectral regions achieves uniform full-spectrum coverage.
3Device complexity
If planar LED emitters are used, then device simplicity is maintained, but beam collimation is limited to no tighter than 8° due to etendue constraints
Solution Approach 1:
The patent replaces the planar LED emitter surface with a curved or spherical phosphor coating surface. This curvature transformation allows the use of reflective optics (such as parabolic mirrors) to effectively collimate the emitted light. The curved surface geometry enables better control of light rays, allowing collimation angles tighter than 8° while maintaining practical device dimensions and avoiding the etendue limitations of planar sources.
4Adaptability or versatility
If traditional lasers are used, then coherent light with narrow band emission is achieved, but electrical energy conversion efficiency is poor (about 20%) and cooling requirements are significant
Solution Approach 1:
The patent uses phosphors as an intermediary medium between the LED light source and the desired laser-like output. The LED generates coherent or partially coherent light that excites the phosphor material, which then emits light with improved spatial coherence and collimation properties. This intermediary approach allows the system to achieve laser-like beam quality without the poor electrical efficiency and cooling requirements of traditional laser diodes.
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 approach enables more efficient collection, dispersion, and projection of light, allowing for higher optical efficiency and better control of light output, particularly in applications like searchlights, theatrical fixtures, and cinema lighting, by overcoming the limitations of existing technologies in achieving full-spectrum white light and tight collimation.
Implementation Method 1
a laser module configured to generate coherent light
Implementation Method 2
a phosphor capsule located proximate a focus of the concave mirror and configured to receive and phosphoresce in response to the coherent light
Implementation Method 3
the concave mirror configured to steer the resulting light in a direction
Data Source
AI summary
A lighting apparatus and method of steering light from a laser-excited phosphor element. In one embodiment, the lighting apparatus includes: (1) a laser module configured to generate coherent light, (2) a concave mirror and (3) a phosphor capsule located proximate a focus of the concave mirror and configured to receive and phosphoresce in response to the coherent light and project resulting light upon the concave mirror, the concave mirror configured to steer the resulting light in a direction.