Parabolic Reflector Design for Low Glare LED Lighting
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Solution Overview
Problem
LED lighting devices often cause discomfort and visual fatigue due to high Unified Glare Rating (UGR) and non-uniform illumination, which is costly to address with existing solutions that involve complex and expensive manufacturing processes.
Innovation Solution
A reflector with a trapezoidal configuration and specific side wall height ratios, combined with a diffuser, to reduce UGR by directing light into a cardioid or batwing illumination pattern, maintaining high luminous efficiency and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED lighting devices are used, then high luminous output is achieved, but high Unified Glare Rating (UGR) and non-uniform illumination occur
Solution Approach 1:
The reflector is divided into multiple sections (first reflector section, second reflector section, third reflector section) with different surface configurations. Each section segments the light reflection paths to achieve uniform illumination distribution while controlling glare, resolving the contradiction between high luminous output and glare control.
Solution Approach 2:
Different regions of the reflector surface are given different optical properties: the first reflector section has a first surface configuration optimized for certain light directions, while the second and third reflector sections have a second surface configuration for other directions. This local differentiation enables simultaneous achievement of high luminous output and low UGR by tailoring reflection characteristics to specific spatial requirements.
2Object-affected harmful factors
If existing solutions with reflective plates or shields are used to reduce UGR, then glare is reduced, but manufacturing cost increases
Solution Approach 1:
The patent merges the glare reduction function and the light directing function into a single integrated reflector structure. The multiple reflector sections with different surface configurations perform both UGR reduction and illumination uniformity enhancement simultaneously, eliminating the need for separate reflective plates or shields and thereby reducing manufacturing cost while achieving the desired optical performance.
3Object-affected harmful factors
If diffusers are used to cover bright light beams, then UGR is reduced, but manufacturing cost increases
Solution Approach 1:
The patent extracts the glare reduction function from the diffuser component and integrates it directly into the reflector structure through the specially designed surface configurations of the multiple reflector sections. This eliminates the need for separate diffuser materials and reduces manufacturing complexity while maintaining the UGR reduction effect.
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 effectively reduces UGR to less than 19 while maintaining high illumination intensity, providing comfortable and efficient lighting with simplified and cost-effective manufacturing.
Implementation Method 1
two opposite side walls have respective inner surfaces configured to correspond to two symmetrical halves of a light-reflective parabolic surface
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
The present invention provides a reflector (100, 400) intended for lighting source comprising a reflector body (110) having reflective side walls (130A, 130B, 130C, 130D, 430A, 430B, 430C, 430D), a top opening (120, 420) and a bottom opening (140, 440). An inner surface of the side wall (130A, 130B, 130C, 130D, 430A, 430B, 430C, 430D) is configured to be a light-reflective parabolic surface (432), a parabola of the light-reflective parabolic surface (432) having two end points and a parabola vertex, the parabola vertex being closer to the top opening (120, 420) with respect to the bottom opening (140, 440), a height between a connection line connecting the two end points of the parabola and the parabola vertex being a height H of the parabola. A ratio h/L of a height h of the side walls (130A, 130B, 130C, 130D, 430A, 430B, 430C, 430D) to a length L of the bottom opening (140, 440) is between 0.4 and 0.7, a ratio h/H of the height h of the side walls (130A, 130B, 130C, 130D, 430A, 430B, 430C, 430D) to the height H of the parabola is between 0.55 and 0.75, and a ratio h/l of the height h of the side walls (130A, 130B, 130C, 130D, 430A, 430B, 430C, 430D) to a length l of the top opening (120, 420) is between 0.3 and 0.55. The present invention also provides a lighting device (500) comprising the above reflector (100, 400), which is able to reduce the Unified Glaring Rating (UGR) while maintaining high luminous efficiency.