Edgelit Optical Element for Uniform Direct Downlighting
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Solution Overview
Problem
Traditional lighting systems with optical waveguides face inefficiencies in light coupling, leading to 10-30% light loss and non-uniform brightness due to hotspotting, which is exacerbated by the need for bezels to hide these issues.
Innovation Solution
The use of optical elements with angled input edges and overhang features, combined with light scattering materials and a cover lens, enhances light outcoupling and reduces hotspotting, allowing for increased direct transmission and uniform light distribution without the need for bezels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional optical waveguides are used for light coupling, then the light guide can be positioned close to the light source providing thin form factor, but 10-30% of light is lost due to inefficient optical coupling
Solution Approach 1:
The optical element is divided into multiple functional zones: an input face for light entry, angled input edges for controlled outcoupling, and an output face for light exit. This segmentation allows different portions of the optical element to perform specific functions, optimizing both light transmission and spatial efficiency.
Solution Approach 2:
The patent introduces angled input edges that create a third dimension of light control by directing light outcoupling at specific angles. This angular dimension allows precise control of light paths, reducing loss while maintaining the thin profile of the optical element.
2Productivity
If full edge coupling of light into optical waveguides is attempted, then light utilization should be maximized, but hotspotting occurs near the light source requiring bezels to hide non-uniform brightness
Solution Approach 1:
Different regions of the optical element are designed with different properties: the input edges have specific angles to control outcoupling, the bulk provides light guidance, and the output face delivers uniform light. This local differentiation allows high light utilization while preventing hotspotting in any single region.
Solution Approach 2:
Instead of trying to prevent outcoupling at the edges with bezels, the patent inverts the approach by designing the input edges with specific angles that actively control and utilize the outcoupled light. This transforms the problematic edge region into a functional light-management feature.
3Illumination intensity
If bezels are added to hide hotspotting, then non-uniform brightness is concealed, but the light emitting area percentage is reduced and device complexity increases
Solution Approach 1:
The patent extracts the brightness uniformity function from a separate bezel component and integrates it directly into the optical element's geometry. The angled input edges and internal light distribution mechanisms provide uniformity without requiring an additional bezel structure, thereby maximizing the light emitting area.
4Speed
If light sources such as LEDs are coupled into optical light guides, then light directionality is improved, but color output variation over angle is accentuated
Solution Approach 1:
The optical element serves multiple functions simultaneously: it provides directional light control through its geometry, ensures color consistency through controlled light paths, and maintains brightness uniformity through its angled edge design. This multi-functionality resolves the trade-off between directionality and color consistency.
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 configuration increases light output efficiency by 16% at 45 degrees and achieves a more uniform brightness and color distribution, reducing hotspotting and light loss, while maintaining a thin form factor.
Implementation Method 1
optical elements that functions simultaneously as an outcoupling TIR light guide
Implementation Method 2
light scattering materials and a cover lens, enhances light outcoupling and reduces hotspotting
Data Source
AI summary
Various light fixtures are provided for mounting within and below suspended grid ceilings incorporating T-bars and ceiling panels. The light fixtures comprise a double or single edgelit planar or wedge shaped optical element that functions simultaneously as an outcoupling TIR light guide and a light scatterer or direct throughput lens. It provides a number of benefits because of its edgelit design including; thin forms and shallow depth, extended emitting area and controlled lighting distributions from one or two light guide faces. Additionally, areas typically dedicated to bezels or edge reflectors can be greatly reduced or eliminated due to decreased hotspotting to provide a fixture face with very high percentage of light emitting area. Embodiments are described for direct, indirect, and direct indirect configurations. The embodiments provide increased light output, uniformity of brightness and color and controlled direct and indirect lighting distributions and with single or dual off axis intensity peaks. Such light distributions are particularly useful in applications such as direct illumination of offices, schools, hospitals, retail or commercial spaces and table tops or work surfaces or indirect illumination of ceilings, wall washing and surface area lighting as well as other lighting applications.