Tubular LED Reflector with Central Constriction for Uniform Road Illumination
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Solution Overview
Problem
Existing LED lighting fixtures struggle to efficiently illuminate longitudinally extending surfaces, such as roads, due to inefficient use of light flux and glare from point-like light sources, leading to non-uniform illumination and energy wastage through reflection and scattering.
Innovation Solution
The design of an LED reflector module with a tubular reflector having a central constriction and funnel-shaped openings, where part of the Lambertian light distribution is emitted directly without reflection, and strategically arranged partial reflector surfaces direct light to optimize illumination of elongated areas, reducing energy loss and glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If all light from the LED is directed through a reflector surface, then uniform illumination can be achieved, but energy loss through absorption and scattering increases
Solution Approach 1:
The reflector is segmented into multiple zones (first partial reflector surfaces, second partial reflector surfaces, and funnel-shaped zones) with different functions. The first zones reflect light for distant illumination, the second zones reflect light for near-field illumination, and the funnel zones allow direct light transmission, eliminating the need for all light to undergo reflection and reducing energy loss.
Solution Approach 2:
Different regions of the reflector are assigned different optical properties and functions. The first partial reflector surfaces are positioned to reflect light at smaller angles for distant surfaces, while the second partial reflector surfaces reflect light at larger angles for near zones. The funnel-shaped regions provide direct light transmission without reflection, creating local quality variations that optimize both illumination uniformity and energy efficiency.
2Device complexity
If a point-like LED source is used, then device complexity is reduced, but glare is generated
Solution Approach 1:
The tubular reflector geometry transforms the point-like light source into a distributed light-emitting structure. The funnel-shaped zones extend the light emission in the longitudinal direction, creating a line-like light distribution that reduces the intensity concentration and eliminates glare while maintaining the simplicity of the LED source.
3Illumination intensity
If light is reflected multiple times to achieve uniform illumination, then illumination uniformity improves, but productivity decreases due to energy loss
Solution Approach 1:
The reflector is divided into multiple functional zones that each contribute to illumination uniformity through a single reflection or direct transmission. The first partial reflector surfaces illuminate distant areas, the second partial reflector surfaces illuminate near zones, and the funnel-shaped zones provide direct light transmission. This segmentation allows uniform illumination to be achieved without multiple reflections, maintaining high lighting efficiency.
4Illumination intensity
If lens elements are added to direct light, then light distribution is improved, but energy loss through absorption and scattering increases
Solution Approach 1:
The patent extracts and utilizes the naturally occurring Lambertian light distribution component that already points in suitable directions for illuminating elongated areas. This portion of light is decoupled from the reflector module without requiring reflection or refraction through lens elements, eliminating energy loss associated with optical components while maintaining effective light distribution.
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 solution achieves uniform illumination of roads with increased efficiency by directing at least 10% to 50% of the LED's luminous flux directly and distributing the remaining flux through carefully angled reflector surfaces, reducing energy loss and ensuring uniform brightness across the illuminated area.
Implementation Method 1
An LED without light-directing optics usually emits a homogeneous light distribution in all directions, which is also referred to as Lambertian light distribution
Implementation Method 2
part of the total luminous flux emitted by the LED emerges from the openings as a bundle of rays without prior reflection on the reflector surface
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5d
AI summary
The module has a tubular reflector including two apertures (6) and a reflector surface that is formed at an inner side of the tubular reflector. A set of LEDs is arranged inside the reflector at a region of a constriction (2) formed at the center of the reflector along a longitudinal direction. The reflector is expanded in the shape of a funnel from the constriction to the apertures such that 10 to 50 percentages of total light beams emitted by the LEDs is discharged as radiation beam through the apertures without prior reflection at the reflector.