Variable Curvature Reflector Facets for Homogeneous Light Mixing
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Solution Overview
Problem
Conventional reflectors for semiconductor light sources suffer from inefficient light mixing, leading to inhomogeneous illumination with large opening angles and light absorption, resulting in unsuitable beam width and color artifacts.
Innovation Solution
A reflector design where the radius of curvature of facets varies based on their distance from the light source, allowing for precise control of light beam expansion and aperture angle, ensuring optimal light mixing and homogeneous illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional reflectors with fixed curvature facets are used, then light mixing is achieved through beam widening, but the opening angle becomes too large and light absorption increases
Solution Approach 1:
The patent applies dynamics by making the facet curvature variable rather than fixed. The radius of curvature changes continuously along the longitudinal direction, allowing the reflector to dynamically adapt light reflection angles for different incident rays. This dynamic curvature design optimizes light mixing while controlling beam opening angle and reducing light absorption losses.
Solution Approach 2:
The patent implements local quality by assigning different radius of curvature values to different longitudinal positions of the facets. Each section of the facet has a locally optimized curvature tailored to the specific light mixing requirements at that position, rather than using a uniform curvature throughout. This local optimization improves overall light mixing efficiency while minimizing energy loss.
2Illumination intensity
If facets with strong curvature are used to widen the light beam for mixing, then light mixing improves, but the opening angle of the emitted beam becomes too large
Solution Approach 1:
The continuous variation of radius of curvature along the longitudinal direction enables dynamic control of beam widening. The curvature is stronger where beam expansion is needed for mixing but transitions to weaker curvature toward the exit to control the final opening angle, achieving both objectives simultaneously.
Solution Approach 2:
The patent changes the curvature parameter (radius of curvature) as a function of longitudinal position. By systematically varying this parameter along the facet length, the design achieves optimal light mixing in the interior while maintaining a controlled, smaller opening angle at the light exit side.
3Illumination intensity
If diffuse reflection surfaces are used to improve light mixing, then homogeneity improves, but system efficiency decreases due to light scattering back into the reflector
Solution Approach 1:
The patent uses curved facet surfaces with specific radius of curvature variations to achieve light mixing through controlled reflection geometry rather than diffuse reflection. The curvature directs light rays in specific patterns that promote mixing while maintaining directional control, avoiding the random scattering that causes efficiency losses.
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 reflector achieves the best possible light mixing and the smallest opening angle, producing a homogeneous and pleasant light beam with a specific width, enhancing illumination efficiency and reducing light absorption.
Implementation Method 1
the facets have a reflective surface that is curved in the longitudinal direction and/or in the transverse direction
Data Source
AI summary
In order to avoid, in a reflector for semiconductor light sources, in particular for a downlight, which comprises an interior bounded by a reflector wall and a light emission side which is arranged at a longitudinal end of the reflector and at which the interior is open, wherein a light source point (5) is provided in the interior and in the transverse direction of the reflector, surrounded by the reflector wall, at which a center point of an emitting surface (8) of a light source (6) can be arranged in the reflector, wherein the reflector wall has a recess through which a light source arranged in the reflector can be electrically contacted and fixed, wherein facets (9) are arranged on the inner side of the reflector wall facing the interior, which have a reflective and longitudinally and/or transversely curved surface,The invention proposes that, since the light mixing in the reflector is achieved precisely by the widening of the light beam emitted by the semiconductor light source via scattering at the facet surfaces, the radius of curvature of the facets associated with the longitudinal curvature, averaged over all facets whose surface center is the same distance from the light source point, varies depending on this facet spacing.