Dome-Shaped Diffuser for Uniform LED Illumination
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Solution Overview
Problem
Existing large light emitting panels face challenges in achieving homogeneous illumination with a low LED count while maintaining cost-effectiveness and fire safety, and avoiding color artifacts and critical optical component positioning.
Innovation Solution
A light emitting device comprising one or more LED light sources and dome-shaped diffusely transmissive covers with a constant width-to-distance ratio, allowing for improved illuminance uniformity and forgiving positioning tolerance, made from materials like glass or plastic with optional scattering materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large square array of LEDs is used to illuminate large panels, then homogeneous illumination is achieved, but the building height increases and cost increases
Solution Approach 1:
The patent divides the panel into multiple zones, each illuminated by a limited number of LEDs (e.g., 4-9 LEDs per zone). This segmentation allows each zone to achieve homogeneous illumination independently without requiring a dense global LED array, thereby reducing overall LED count and building height while maintaining illumination uniformity across the entire panel surface
Solution Approach 2:
The patent applies zone-based illumination where each zone has optimized LED placement and optical properties tailored to its specific requirements. This local optimization allows each zone to achieve homogeneous illumination with minimal LEDs, and the combination of zones creates overall homogeneous illumination without requiring a dense global LED array
2Length of stationary object
If the LED pitch is decreased to maintain homogeneous illumination with lower building height, then building height is reduced, but manufacturing cost increases
Solution Approach 1:
By segmenting the panel into zones with limited LEDs per zone, the patent achieves effective illumination coverage without requiring dense LED placement. This reduces the total number of LEDs needed, lowering manufacturing cost while maintaining acceptable building height
Solution Approach 2:
The patent introduces optical elements (diffusers, reflectors, lenses) that manipulate light in three-dimensional space to extend the effective illumination range of each LED. This dimensional approach allows fewer LEDs to cover larger areas without decreasing LED pitch, thereby reducing cost while maintaining building height
3Illumination intensity
If light guides are used for light spreading to achieve homogeneous illumination, then illumination uniformity is improved, but fire safety is compromised
Solution Approach 1:
The patent extracts the light spreading function from traditional plastic light guides and replaces it with alternative optical elements made from fire-safe materials such as glass diffusers, metal reflectors, and ceramic lenses. This extraction maintains illumination uniformity while eliminating the fire safety hazard associated with plastic light guides
Solution Approach 2:
The patent employs composite optical systems combining multiple materials with different fire safety properties (glass, metal, ceramic) to achieve light spreading and homogeneous illumination without relying on flammable plastic light guides, thereby maintaining illumination uniformity while ensuring fire safety
4Productivity
If side emitting optics are used to achieve homogeneous illumination with low LED count, then illumination efficiency is improved, but positioning precision requirements increase and cost increases
Solution Approach 1:
By dividing the panel into zones with optimized LED placement, the patent achieves efficient illumination without requiring precise positioning of individual LEDs. Each zone is independently optimized, allowing for more forgiving positioning tolerances while maintaining overall illumination efficiency
Solution Approach 2:
The patent optimizes illumination efficiency by adjusting parameters such as LED-to-zone ratios, optical element dimensions, and material properties rather than relying on precise positioning. This parameter optimization maintains high illumination efficiency while reducing positioning precision requirements and associated costs
5Adaptability or versatility
If multiple LEDs with different colors are used for color tunability, then color versatility is improved, but color over angle effects occur with side emitting lenses
Solution Approach 1:
The patent divides the panel into zones, each containing multiple LEDs of different colors. This segmentation allows each zone to independently control color output, achieving color tunability while minimizing color over angle effects through localized color mixing rather than relying on side emitting lenses that exacerbate angular color variations
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 provides a uniformly lit large area panel with reduced LED count and cover area, ensuring cost-effectiveness and fire safety, while optimizing illuminance uniformity and promoting side-emission over top-emission, achieving high illuminance homogeneity without color artifacts.
Implementation Method 1
one or more diffusely transmissive covers. The one or more diffusely transmissive covers extend over the one or more LED light sources
Data Source
AI summary
The present invention relates to a light emitting device comprising one or more LED light sources and one or more diffusely transmissive covers. The one or more diffusely transmissive covers extend over the one or more LED light sources to form one or more combinations of an LED light source and a diffusely transmissive cover. For each combination of an LED light source and a diffusely transmissive cover (i) the diffusely transmissive cover is dome-shaped with a vertical cross-section having a closed convex shape and a horizontal cross-section having a polygonal shape, (ii) the diffusely transmissive cover has a width (w) projected in a horizontal plane parallel to a bottom of the diffusely transmissive cover, (iii) the LED light source has a distance (d) to any neighboring LED light source. The width (w) and the distance (d) are perpendicular to each other, and the ratio of the width (w) and the distance (d) is constant.