Polynomial Faceted Reflector for LED Lighting Uniformity
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Solution Overview
Problem
Conventional light projectors with parabolic reflectors suffer from excessive axial intensity, secondary reflections causing dazzling, and color temperature variations leading to yellowish spots, especially when using LED light sources, due to the need for highly curved facets and production irregularities in reflective surfaces.
Innovation Solution
A lighting device featuring a cup-shaped reflector with a polynomial faceted internal surface and a flared shield, where the reflective surfaces have a wide radius and are designed to ensure single reflection efficiency, uniformity, and controlled beam emission, eliminating defects and dazzling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If highly curved facets are used to widen the light beam, then the beam amplitude increases, but secondary reflections occur causing dazzling and reducing optical efficiency
Solution Approach 1:
The patent applies local quality by varying the curvature radius of facets in different zones of the reflector. Facets closer to the optical axis have different curvature radii than those farther away, allowing each zone to optimize between beam widening and minimizing secondary reflections. This localized adjustment of optical properties resolves the contradiction by preventing excessive curvature in areas where it causes harmful reflections.
Solution Approach 2:
The patent changes the parameter of curvature radius systematically across the reflector surface. By defining specific curvature radius ranges for different angular zones (e.g., 0-30 degrees from axis versus 30-60 degrees), the design optimizes beam amplitude while controlling secondary reflections through parameter variation rather than uniform high curvature.
2Loss of energy
If mirror-polished reflective surfaces are used, then reflectivity is high, but production irregularities make the reflector appear bright and reduce optical performance
Solution Approach 1:
The patent replaces the requirement for expensive, perfectly smooth mirror-polished surfaces with a faceted surface structure that is more tolerant of manufacturing variations. The faceted design inherently masks small irregularities, allowing the use of more economical manufacturing processes while maintaining high effective reflectivity and eliminating the unwanted brightness effect.
3Use of energy by moving object
If LED light sources are used, then energy efficiency improves, but color temperature variations create yellowish spots on white backgrounds
Solution Approach 1:
The patent applies local quality by directing different portions of the LED emission spectrum to different spatial zones. The faceted reflector design and specific facet orientations ensure that blue-rich and yellow-rich portions of the LED spectrum are distributed uniformly across the illumination field, compensating for the inherent color temperature variation in LED sources and achieving uniform white light output.
4Adaptability or versatility
If parabolic reflectors with radial facets are used, then beam emission control improves, but excessive axial intensity remains in the emitted beam
Solution Approach 1:
The patent systematically changes the curvature radius parameter of facets based on their angular position from the optical axis. By defining specific curvature ranges for different angular zones, the design redistributes the axial intensity while maintaining beam emission control, reducing the peak intensity on the axis while preserving overall beam directionality and amplitude control.
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 solution achieves high efficiency, uniform lighting, and complete control over beam emission, eliminating defects and dazzling, while maintaining optical performance and preventing unwanted light rings and yellowish spots.
Implementation Method 1
a reflector (5) having an internal reflective surface (17) formed by a pattern of reflective sectors (21) or facets arranged on a polynomial base surface (22)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A lighting device (1), in particular a LED lighting device, comprises at least one light source (3) and a reflector (5) extending along and around a longitudinal axis (Z) and having an internal reflective surface (17) arranged so as to intercept at least part of the light emitted by the light source (3) and reflect said part towards a light exit opening (15); the internal reflective surface (17) is a faceted polynomial surface.