3D Luminescent Concentrator With Mirror-Guided Brightness Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional luminescent concentrators pumped by LEDs have limited brightness and are constrained by the geometry of their output beam, with 1D and 2D concentration methods limiting pumping power and requiring thick crystals for maximum absorption, which can reduce brightness.
Innovation Solution
A 3D light-emission device with mirrors covering lateral faces to increase reflections and a brightness triggering element that generates radiation within the crystal, allowing rays to travel further before exiting, thereby enhancing output brightness and flexibility in beam parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional 1D or 2D concentrator geometry is used, then the crystal can be pumped by LEDs, but the output brightness is limited and the beam geometry is constrained
Solution Approach 1:
The patent transitions from conventional 1D or 2D concentrator geometries to a 3D concentrator design where the crystal absorbs pump radiation volumetrically throughout its entire volume. This dimensional change allows light to be absorbed and re-emitted from all directions within the crystal, enabling the output beam to be extracted through lateral faces rather than only through the pump face, thereby increasing brightness and providing flexibility in beam parameter control.
2Loss of energy
If the crystal thickness is increased to maximize absorption, then absorption efficiency improves, but brightness is reduced due to increased path length and losses
Solution Approach 1:
The 3D concentrator design allows pump radiation to be absorbed throughout the entire crystal volume rather than only along a single path through a thick crystal. By extracting the output beam through lateral faces, the patent achieves efficient absorption without the brightness penalties associated with increased path length through thick crystals, as the light can exit through multiple directions.
Solution Approach 2:
The patent applies different optical properties to different regions of the crystal by using wavelength-selective mirrors on specific lateral faces. These mirrors reflect pump radiation back into the crystal for continued absorption while allowing the broader emission spectrum to pass through, creating local optical enhancements that improve both absorption efficiency and brightness simultaneously.
3Illumination intensity
If wavelength-selective mirrors are added to lateral faces, then brightness is enhanced through increased reflections, but device complexity increases
Solution Approach 1:
The patent utilizes wavelength-selective mirrors that exploit the Stokes shift between the pump radiation wavelength and the emission wavelength. The mirrors are designed to reflect only the narrow pump wavelength band while transmitting the broader emission spectrum. This parameter-based selectivity allows the mirrors to perform multiple functions (enhancing absorption and enabling lateral extraction) without requiring complex multi-layer structures or active control mechanisms.
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 3D concentration method significantly increases output brightness by multiple reflections within the crystal, providing greater flexibility in beam parameters and material specifications, surpassing the limitations of 1D and 2D concentrators in terms of brightness and absorption efficiency.
Implementation Method 1
The crystal is configured to absorb said light-emitting radiation Ld. The flow of light emitted by the LEDs and directed towards the lighting face is absorbed by the luminophores Lum of the fluorescent crystal, which are distributed in all of the volume of the crystal, and thus emit fluorescence radiation in the interior of the crystal.
Implementation Method 2
the trapped rays which are known as Lp: these rays are trapped in the crystal as a result of the total internal reflection (RTI) on the different faces of the crystal.
Data Source
AI summary
A light-emission device includes at least one emission module comprising: a luminescent crystal known as a concentrator crystal with at least six faces which are parallel in pairs, including a first and a second face, known as lateral faces, perpendicular to a direction x and separated by a distance corresponding to a horizontal dimension of the concentrator in the direction x; a first mirror, which is configured such as to cover the first lateral face at least partly, defining a surface area covered by the first mirror, and at least one surface area (SFS1) which is not covered by the first mirror defining an associated output face; a second mirror, which is configured such as to cover at least 95% of the second lateral face; a brightness triggering element, which is designed to generate emission of brightness radiation (LF) in the luminescent crystal; a ratio R between the non-covered surface area (SFS1) and a surface area (SL) of the first lateral face being determined such that rays of the brightness radiation are reflected on the first and second mirrors, and are propagated over a mean distance Lmoy such thatLp=1α>Lmoy≫ Lwithin the luminescent crystal before passing through at least one output face, forming an output beam, where α is a coefficient of loss per unit of length of the concentrator for the brightness radiation.