LED Light Fixture Uniformity via Variable Density Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LED-based light fixtures using tapped linear drivers often exhibit non-uniform brightness due to inherent operational variations, making it aesthetically unappealing when viewed from a distance.
Innovation Solution
The implementation of light extraction patterns with varying densities on a light guide, where brighter LEDs are paired with sparser patterns and dimmer LEDs with denser patterns, to balance out light output and achieve uniform brightness across the fixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a tapped linear driver is used to power LEDs in a light fixture, then the device complexity is reduced and manufacturing cost is lowered, but the brightness uniformity across the fixture deteriorates
Solution Approach 1:
The patent applies local quality by varying the density of light extraction features at different locations on the light guide. Specifically, regions corresponding to brighter LEDs have lower feature density, while regions corresponding to dimmer LEDs have higher feature density. This localized variation in extraction efficiency compensates for LED brightness variations, achieving uniform overall illumination without requiring complex driver circuits.
2Manufacturing precision
If uniform light extraction features are used across the light guide, then the manufacturing precision is simplified, but the brightness uniformity deteriorates due to LED variations
Solution Approach 1:
Instead of using uniform light extraction features throughout, the patent implements location-dependent feature density variation. The light extraction features are strategically distributed with lower density in regions corresponding to brighter LEDs and higher density in regions corresponding to dimmer LEDs. This approach maintains manufacturing simplicity while achieving brightness uniformity through spatially varying extraction characteristics.
3Illumination intensity
If the light extraction feature density is increased to compensate for dimmer LEDs, then the brightness uniformity improves, but the light extraction efficiency for brighter LEDs deteriorates
Solution Approach 1:
The patent optimizes light extraction efficiency by matching feature density to local LED brightness characteristics. Brighter LEDs are positioned in regions with lower feature density, reducing unnecessary light extraction and minimizing energy loss. Dimmer LEDs are positioned in regions with higher feature density, ensuring sufficient light extraction. This localized optimization achieves brightness uniformity while minimizing overall energy loss.
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 approach effectively compensates for brightness variations, resulting in a more uniform light output, making the fixture appear consistently bright from different distances.
Implementation Method 1
a light guide (420) provided with a plurality of light extraction patterns
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~2C
AI summary
An illumination system is disclosed that is arranged to compensate for variations in brightness between different LEDs in the system. The system may include an array of LEDs coupled to a light guide that is provided with a plurality of light extraction patterns. Each light extraction pattern may include a plurality of light extraction features. The light extraction patterns may differ from one another in the density of the features. Light extraction patterns having a greater density may be combined with LEDs in the array that are less bright, whereas light extraction patterns having a lower feature density may be combined with LEDs in the array that are brighter.