Anisotropic Light Deflection Particles for LED Illumination Homogenization
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Solution Overview
Problem
LED-based lighting devices face challenges in achieving uniform light distribution due to their Lambertian emission characteristic, particularly when replacing fluorescent lamps, as the light emitted passes through a transmission window, requiring effective homogenization of illuminance distribution while minimizing light loss and maintaining efficiency.
Innovation Solution
Incorporating anisotropic light deflection particles embedded in the transmission window material, aligned along the longitudinal axis of the lighting device, which fan out light more in sectional planes containing the longitudinal axis than in planes perpendicular to it, allowing for homogenization of illuminance distribution and potential lens functions for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are arranged side by side with certain distance to emit light, then energy efficiency is improved compared to conventional light sources, but illuminance distribution on the transmission window becomes non-uniform
Solution Approach 1:
The patent introduces an anisotropically scattering diffuser layer as an intermediary component between the LEDs and the transmission window. This diffuser layer scatters the light from the spaced-apart LEDs in a controlled manner, creating a uniform illuminance distribution on the transmission window while preserving the energy efficiency benefits of LED technology.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing a diffuser layer with specific scattering properties. The anisotropic scattering characteristics of this layer modify the light distribution pattern, transforming the non-uniform illuminance from spaced LEDs into a uniform distribution on the transmission window.
2Illumination intensity
If a diffuser layer is added to homogenize illuminance distribution, then uniformity is improved, but light loss increases and efficiency decreases
Solution Approach 1:
The patent applies local quality by using an anisotropically scattering diffuser layer that provides different scattering behavior in different directions. The scattering is stronger in directions that need homogenization while maintaining lower loss in the primary light transmission direction, thus achieving uniformity with minimized energy loss.
Solution Approach 2:
The patent optimizes the scattering parameters of the diffuser layer to achieve the right balance between homogenization and light loss. By carefully controlling the scattering angle distribution and scattering coefficient, the system achieves uniform illuminance distribution while minimizing the amount of light that is scattered away from the useful transmission path.
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 effectively homogenizes the light distribution on the exit side of the transmission window, reducing the appearance of individual LEDs as separate points of light to a continuous strip, while maintaining efficiency by minimizing light loss and allowing for geometric ray optics adjustments in both near and far fields.
Implementation Method 1
the light deflection particles (also just 'particles' for the sake of simplicity) are anisotropic in their deflection properties and aligned in such a way that the respective deflection axis extends along the longitudinal axis of the lighting device
Implementation Method 2
With the light deflection particles embedded in the transmission window material, an illuminance distribution generated by the LEDs on the entry side on the transmission window
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3b
AI summary
The present invention relates to a lighting device (30) with a plurality of LEDs (32) arranged side by side along a longitudinal axis (31) of the lighting device (30) and a planar transmission window (35) made of a transparent transmission window material (1) in which anisotropic light deflection particles (2) are embedded, each having a deflection axis (3) and a passage axis (4) perpendicular to it, wherein light incident perpendicular to the two axes (3, 4) is more strongly fanned out on the deflection axis (3) than on the passage axis (4), and wherein the light deflection particles (2) are mostly oriented such that the respective deflection axes (3) extend along the longitudinal axis (31) of the lighting device (30).