Narrow-Aperture Light Guide Structure for Low-Glare Luminaires
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Solution Overview
Problem
Designing luminaires with narrow apertures that minimize high-angle glare while providing sufficient illumination and aesthetically pleasing homogeneous light is challenging, especially with point sources like LEDs.
Innovation Solution
The use of light guides with elongated bases and collimators that internally reflect light at lower angles, combined with notches and protrusions to control glare and homogenize light distribution, along with baffles to block high-angle light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If narrow aperture luminaires are designed to reduce high angle glare, then visual comfort is improved, but light output from the narrow aperture is reduced
Solution Approach 1:
The luminaire aperture is segmented into multiple narrow sub-apertures or optical zones, each controlled by independent light guides or diffusers. This segmentation allows selective control of light angles from different portions of the aperture, enabling glare reduction in certain zones while maintaining overall light output through other zones.
Solution Approach 2:
Light guides or optical intermediaries are introduced between the light source and the aperture to manipulate light distribution. These intermediaries use total internal reflection, refraction, or diffusion to redirect high-angle light away from the aperture while allowing lower-angle light to pass through, thus reducing glare without proportionally reducing light output.
2Adaptability or versatility
If point sources of light are used in narrow aperture luminaires, then design flexibility is improved, but high angle glare is increased
Solution Approach 1:
Light guides serve as intermediaries between point light sources and the aperture. These light guides capture light from the point sources and redistribute it through their length, transforming the point source emission pattern into a more uniform, lower-angle distribution at the aperture, thereby eliminating glare while preserving design flexibility.
Solution Approach 2:
The optical parameters of the light distribution are changed by using light guides with specific refractive indices, internal reflection angles, and exit surface characteristics. This transforms the high-angle emission from point sources into a controlled, lower-angle beam that reduces glare while maintaining the benefits of point source lighting.
3Illumination intensity
If narrow aperture luminaires are designed to provide sufficient illumination, then workspace illumination is improved, but high angle glare is increased
Solution Approach 1:
The aperture is divided into multiple optical zones or channels, each optimized for specific light distribution patterns. Some zones are optimized for direct illumination to maintain workspace lighting, while other zones are optimized for glare control, allowing the system to achieve both sufficient illumination and reduced high-angle glare simultaneously.
Solution Approach 2:
Different portions of the luminaire aperture have different optical characteristics tailored to their specific functions. For example, lower portions may provide direct illumination while upper portions control glare, or different sections use different diffusers or light guides with optimized properties for their local requirements.
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 glare and ensures uniform light output from narrow apertures, enhancing user comfort and visual aesthetics.
Implementation Method 1
whereby substantially all light received at the light receiving surfaces internally reflects through the collimators and the base and emits from the light emitting surface
Data Source
AI summary
A light guide for a luminaire is provided. The light guide includes: an elongated base having a light emitting surface at a distal end, and opposing major faces; and a plurality of collimators projecting from the base, wherein each collimator has a light receiving surface at a proximal end. The plurality of collimators are arranged with spaces therebetween along the base. The light emitting surface has notches having a minimum width corresponding to the space between the collimators and a maximum width corresponding to a space between the light receiving surfaces. Substantially all light received at the light receiving surfaces internally reflects through the collimators and the base and emits from the light emitting surface, and the notches are configured to direct light emitted from the light emitting surface at a lower angle than if the notches were not present.