Troffer Lens Assembly Reducing Glare via Light Redirection
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Solution Overview
Problem
Solid state lighting fixtures, particularly those using LEDs, often produce high levels of glare due to asymmetric light distribution, leading to undesirable unified glaring ratios (UGR) when light is emitted at high angles, causing discomfort and unsightly reflections.
Innovation Solution
The implementation of a lens assembly with light redirection features, such as a prismatic inner surface, inner lens, louver assembly, or reflector, to redirect light emitted at high angles, reducing the UGR and providing a more diffuse and pleasing lighting effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If LED light sources are used to reduce energy consumption and increase operational lifetime, then energy efficiency and durability are improved, but asymmetric light distribution causes high glare levels and undesirable UGR
Solution Approach 1:
A lens assembly is introduced as an intermediary component between the LED light source and the environment. The lens assembly includes light redirection features that modify the asymmetric light distribution pattern, redirecting light away from high-angle directions that cause glare while maintaining the energy efficiency benefits of LED sources.
2Area of stationary object
If light is emitted at high v-angles to provide broad illumination coverage, then illumination area is improved, but unified glaring ratio (UGR) increases causing discomfort
Solution Approach 1:
The lens assembly features locally varied optical properties with different zones designed to redirect light from specific angular ranges. The light redirection features are strategically positioned and shaped to target high v-angles (greater than 70 degrees) specifically, redirecting these problematic rays away from the housing while allowing lower-angle light to maintain broad illumination coverage.
3Object-generated harmful factors
If a lens assembly with light redirection features is added to reduce glare and UGR, then glare control is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functional elements into a unified lens assembly structure. The light redirection features are combined with the lens housing into a single integrated component rather than separate parts, reducing assembly complexity while maintaining effective glare control through the coordinated action of the prismatic surfaces and lens geometry.
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 lens assembly effectively reduces glare by redirecting light away from the housing, resulting in a lower UGR and a more uniform, soft lighting distribution, enhancing the aesthetic and functional performance of troffer-style lighting fixtures.
Implementation Method 1
a lens coupled to the housing and extending over the light engine
Implementation Method 2
a reflector disposed about the light engine and under the lens. The reflector is configured to redirect light from the light engine away from the housing
Implementation Method 3
The lens has a prismatic inner surface facing the light engine
Data Source
AI summary
A lighting fixture with reduced glare is provided. Lighting fixtures described herein use a lens assembly to redirect light away from a housing in order to reduce a unified glaring ratio (UGR) (e.g., when viewed crosswise or endwise). The lens assembly may further provide diffusive properties which result in a more pleasing and soft light over traditional lighting fixtures. In aspects described herein, the UGR of troffer-style lighting fixtures can be improved (e.g., reduced) through lens assemblies having one or more light redirection features configured to particularly redirect light emitted at high v-angles (e.g., light emitted sideways relative to the housing at v-angles greater than 70 degrees). For example, the lens assembly may include an inner prismatic surface of a lens, an inner lens, a louver assembly (e.g., over or under a lens), or a reflector to achieve this light redirection.