Batwing Optical Diffuser for Uniform LED Illumination
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Solution Overview
Problem
Conventional lighting systems, particularly those using LEDs, often produce Lambertian light distributions that result in uneven illumination of flat surfaces, with excessive intensity at the nadir and decreased intensity at angles, leading to inefficiencies and undesirable 'hot spots', and existing solutions for creating batwing distributions are costly, complex, and inefficient.
Innovation Solution
A light distribution device featuring a light transmissive substrate with parallel linear prisms on one face, configured to connect to a linear light source in a concave position, directing light into a batwing pattern by using outward-facing prisms in specific cross-sectional shapes, such as arcs or elliptical forms, and optionally combined with reflectors and diffusers to enhance efficiency and aesthetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Lambertian light distribution is used, then the light source structure is simple, but the illumination uniformity deteriorates with hot spots at nadir
Solution Approach 1:
A batwing diffuser is introduced as an intermediary optical element between the Lambertian LED light source and the target surface. The diffuser modifies the light distribution pattern by scattering and redirecting light rays, transforming the concentrated nadir illumination into a uniform batwing distribution that eliminates hot spots while maintaining simplicity of the LED source structure.
Solution Approach 2:
The patent changes the angular distribution parameter of the light output by using a batwing diffuser with specific optical properties. The diffuser is designed to redirect light at specific angles, transforming the cosine-based Lambertian distribution into a batwing distribution with enhanced lateral illumination and suppressed nadir intensity, thereby achieving uniform illumination without changing the simple LED source.
2Illumination intensity
If conventional batwing distribution solutions are implemented, then illumination uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs a cost-effective batwing diffuser made from relatively inexpensive materials such as translucent plastic or glass with engineered surface microstructures. This affordable optical element achieves the desired batwing distribution without requiring complex multi-component optical systems, expensive precision lenses, or intricate reflector assemblies, thereby maintaining low system complexity and cost while delivering uniform illumination.
3Illumination intensity
If nadir intensity is increased, then central brightness is improved, but energy efficiency deteriorates due to unnecessary over-illumination
Solution Approach 1:
The batwing diffuser creates a non-uniform angular distribution where different regions of the illuminated surface receive appropriately tailored light intensities. The diffuser redirects light preferentially toward lateral areas that require illumination, while intentionally reducing nadir intensity. This local optimization of light distribution ensures that energy is delivered precisely where needed on the target surface, eliminating wasteful over-illumination at the center and improving overall 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 achieves a batwing light distribution that provides uniform illumination with reduced intensity at nadir, increased efficiency, and a pleasing visual appearance, while minimizing retro-reflection and maintaining high first-pass transmission, thus optimizing luminaire performance and design.
Implementation Method 1
A light distribution device features a light transmissive substrate with parallel linear prisms on one face, configured to connect to a linear light source in a concave position, directing light into a batwing pattern
Data Source
AI summary
A light distribution device includes a light transmissive substrate having first and second opposing faces and a plurality of substantially parallel linear prisms on the second face that extend in a longitudinal direction of the substrate. The light distribution device is configured to connect to a light assembly including a linear light source with the first face of the substrate facing the light source, with the linear prisms substantially parallel to a light source longitudinal axis and with and the substrate having a non-planar cross-sectional shape such that at least a major portion of the substrate is concave relative to the light source. When connected, the light distribution device is configured to receive light from the light source and distribute the light emerging from the second face of the substrate in a batwing distribution pattern in a plane perpendicular to the light source longitudinal axis.