Textured Reflector for LED Glare Reduction
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Solution Overview
Problem
LED lighting systems face issues with glare and color hot spots due to the use of specular or semi-specular reflective materials, which can image the LED light source and create unwanted reflections, especially when multiple color LEDs are used to produce white light.
Innovation Solution
A lighting system with a textured reflector made from materials like polycarbonate, which is either standalone or fixed to a metal substrate, is designed to direct at least 70% of the light onto its surface, minimizing glare and imaging without the need for a costly diffuse white layer. The reflector can have a prismatic or roughened pattern, varying spatially relative to the LED light source, to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a specular or semi-specular reflective material is used, then reflectivity is improved, but glare and color hot spots increase due to imaging of the LED light source
Solution Approach 1:
The reflector surface is divided into multiple zones with different texturing characteristics. The region closer to the LED light source has a first texture pattern with specific properties, while the region farther from the light source has a second texture pattern with different properties. This local differentiation allows each zone to perform its specific function optimally - closer zones manage glare while farther zones maintain reflectivity and color mixing.
Solution Approach 2:
The texture patterns on the reflector surface vary in parameters such as depth, orientation, and distribution across different regions. By changing these texturing parameters spatially, the system achieves different optical behaviors in different zones - reducing glare in certain areas while preserving reflectivity in others, thus resolving the contradiction between high reflectivity and minimal glare.
2Object-affected harmful factors
If a diffuse white layer is used to reduce glare, then glare is reduced, but cost increases
Solution Approach 1:
The invention extracts and utilizes the texturing feature directly in the reflector material itself, eliminating the need for a separate diffuse white layer. By incorporating the texture pattern directly into the reflector (through methods like co-extrusion or surface treatment), the system achieves glare reduction without adding the cost and complexity of an additional diffuse layer.
Solution Approach 2:
The textured reflector serves multiple functions simultaneously: it provides reflection, reduces glare, and enables color mixing all through its texture pattern. This multi-functionality eliminates the need for separate components (like diffuse white layers), thereby reducing cost and simplifying manufacturing while achieving the desired glare reduction.
3Illumination intensity
If multiple color LEDs are used to produce white light, then color rendering is improved, but imaging of the light source and unwanted reflections increase
Solution Approach 1:
Different regions of the reflector are textured to handle different optical challenges. The texture patterns are designed to scatter and diffuse light from multiple color LEDs while preventing direct imaging of the light source. This local differentiation allows the system to maintain color rendering quality while minimizing unwanted reflections and imaging effects.
Solution Approach 2:
The texture patterns on the reflector are asymmetric in design, with varying orientations and depths that disrupt the symmetry of light reflection. This asymmetry prevents the formation of clear images of the LED light source while maintaining uniform color mixing, thus resolving the contradiction between color rendering and imaging prevention.
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 system effectively reduces glare and color hot spots while maintaining high reflectivity, allowing for efficient color mixing and minimizing reflections in LED lighting fixtures, even with multiple color LEDs or phosphors, by ensuring that a significant portion of the light is incident on the textured surface.
Implementation Method 1
a textured reflector to reflect the light... the textured reflector is textured by way of an imprinted pattern... the pattern may vary spatially relative to the LED light source
Implementation Method 2
a reflector with a textured surface to reflect the light... at least 70% of the light is incident on the textured surface of the reflector... very little to no light is directed straight from the light source into the illumination area
Data Source
AI summary
A light fixture with a textured reflector surface is disclosed. Embodiments of the present invention provide for a lighting system in which LEDs face, and the majority of light form the LED light source is incident on, a textured surface of a back reflector while producing minimal glare and minimal imaging of the light source. Such a reflector may be referred to as a retro-reflector. The reflector for the light fixture can be made from a relatively inexpensive material such as polycarbonate, which without texturing has a specular or semi-specular surface. This material can be used alone or with a metal substrate to form the reflector. The textured surface can be textured by way of an imprinted pattern or by roughening, and can be extruded. A prismatic texture may be used. The texturing can also be spatially varied.