LED Illumination Device Using Dual Conic Reflectors for Uniform Light Distribution
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Solution Overview
Problem
Conventional LED illumination devices produce non-uniform illumination patterns with hotspots, failing to meet the requirement of a 10:1 illuminance ratio in applications like street lighting and automotive lighting, which necessitate highly uniform and non-circular light distributions.
Innovation Solution
The use of reflectors with conic or conic-like shapes, where the LED is positioned to divert high-intensity light away from the central axis and a second reflector fills in lower-intensity light to create a uniform illumination pattern, eliminating hotspots and achieving desired non-circular light distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single reflector is used with LED aligned on central axis, then light collection efficiency is improved, but illumination uniformity deteriorates due to hotspot formation
Solution Approach 1:
The single reflector is divided into two separate reflectors positioned at different locations. The first reflector collects light from one side of the LED while the second reflector collects light from the opposite side, allowing independent optimization of each reflector's function to achieve both high light collection efficiency and uniform illumination distribution without hotspot formation
Solution Approach 2:
Each reflector is designed with specific local optical properties and positioning to redirect light from different angular regions of the LED. The first reflector handles light from one hemisphere while the second reflector handles light from the opposite hemisphere, creating locally optimized light redistribution that results in globally uniform illumination
2Device complexity
If LED and reflector are aligned on central axis, then device simplicity is improved, but illumination pattern becomes circular when non-circular patterns are required
Solution Approach 1:
The two reflectors are positioned asymmetrically relative to the LED, with each reflector oriented to collect and redirect light from different angular regions. This asymmetric configuration enables the generation of non-circular illumination patterns such as rectangular or linear distributions, providing pattern flexibility while maintaining relatively simple device structure
Solution Approach 2:
The illumination pattern control is extended from a single-axis symmetric arrangement to a two-dimensional spatial configuration using two reflectors at different positions and orientations. This dimensional expansion allows independent control of light distribution in multiple directions, enabling versatile pattern generation including rectangular and linear distributions
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 configuration results in a highly uniform illumination pattern with reduced hotspot intensity, meeting the 10:1 illuminance ratio requirement and providing adaptable light distribution for various applications, such as wall-mounted lights and automotive lighting.
Implementation Method 1
a first reflector so that the high intensity light emitted along the central axis of the LED is diverted away from the central axis by the first reflector
Implementation Method 2
A second reflector located opposite the first reflector directs light from a higher angle toward the angle that corresponds to the central axis of the LED
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
An LED (light emitting diode) illumination device that can generate a uniform light output illumination pattern. The illumination source includes first and second reflectors with a conic or conic-like shape. One reflector is mounted in the same plane as the LED and wraps around the front of the LED to redirect the light emitted along a central axis of the LED.