Light Guide with Sloped Foot for Batwing Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light guides using point light sources like LEDs often result in undesirable visible lines of light due to internal reflection and extraction, leading to uneven illuminance and glare, which complicates achieving a visually homogenous light distribution.
Innovation Solution
A vertically oriented light guide with a sloped foot and specific groove configurations that refract light at higher angles for total internal reflection, featuring a combination of sloped faces for controlled light extraction in a batwing distribution, and optional diffuse surfaces to reduce glare and homogenize light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light guides use total internal reflection to guide light, then light can be transmitted through the guide, but visible lines of light (head lamping) appear due to uninterrupted linear reflection paths
Solution Approach 1:
The light guide employs curved or non-linear reflection paths instead of straight linear paths. The extraction elements are positioned and angled to create arc-shaped light trajectories within the guide, which breaks up the direct line-of-sight reflection paths that cause head lamping effects, while still maintaining efficient light transmission from source to exit.
Solution Approach 2:
The light guide incorporates extraction elements with varying properties at different locations along the guide. By adjusting the extraction efficiency, angle, and positioning of elements at different points, the design creates locally optimized light extraction that prevents concentrated visible lines while maintaining overall illumination uniformity.
2Illumination intensity
If light is extracted by extraction elements in conventional light guides, then light can be emitted from the guide, but uneven illuminance and glare occur
Solution Approach 1:
The light guide divides the extraction function into multiple discrete extraction elements distributed along the length of the guide. Each element extracts a portion of the light in a controlled manner, breaking up the continuous extraction process into segmented stages that collectively achieve uniform illuminance distribution across the exit surface.
Solution Approach 2:
The extraction elements utilize variable parameters including different extraction angles, depths, and spacing intervals along the light guide. By systematically varying these parameters, the design optimizes light extraction at each position to compensate for natural light attenuation, achieving uniform illuminance output while controlling glare through optimized extraction angles.
3Use of energy by moving object
If point light sources like LEDs are used in luminaires, then energy efficiency is improved, but achieving even illuminance and reducing glare becomes more difficult
Solution Approach 1:
The light guide acts as an intermediary device between the point LED source and the target surface. It transforms the concentrated point source emission into a distributed linear emission pattern, mediating the transition from high-intensity point source to uniform area illumination, thereby achieving both energy efficiency and uniformity.
Solution Approach 2:
The light guide extends the light emission from a zero-dimensional point source into a one-dimensional linear source along the length of the guide. This dimensional transformation allows the concentrated LED output to be distributed along a line, creating even illuminance across a broader area while maintaining energy efficiency.
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 effectively reduces visible light lines, enhances even illuminance, and minimizes glare, providing a more visually homogenous light distribution across the emitting surface.
Implementation Method 1
Light travels through the light guide by way of total internal reflection until it is extracted
Implementation Method 2
a light receiving surface configured to refract incoming light at higher angles to meet the condition for total internal reflection
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A light guide for luminaires is disclosed. In some embodiments the light guide is oriented to receive light from a point light source at a light receiving surface configured to refract incoming light at angles to enable total internal reflection (TIR) of the light down the body of the light guide without loss of light. A foot at the bottom of the body of the light guide includes a first sloped face wherefrom a portion of the light is extracted downward toward a work plane in a batwing distribution and a second sloped face and a return face wherefrom the remaining light is extracted upward.