3D Light Extraction Block for Uniform OLED Emission
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Solution Overview
Problem
OLED lighting panels suffer from low light extraction efficiency due to waveguiding, resulting in limited useful illumination, and existing light extraction enhancements fail to provide uniform emission intensity and color across all viewing angles.
Innovation Solution
Combining light extraction blocks of varying shapes with light diffusing layers on emissive surfaces to create multiple emitting surfaces and normals, achieving uniform emission intensity and color across a wide range of viewing angles, and transforming 2-dimensional OLED sources into 3-dimensional light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a light extraction block with sharply angled sides is used to direct light towards the front surface, then light extraction efficiency is improved, but emission uniformity across viewing angles deteriorates
Solution Approach 1:
The light extraction block is divided into multiple segments or facets, each oriented at different angles. This segmentation allows light to be extracted and directed toward multiple viewing angles simultaneously, resolving the contradiction between improving light extraction efficiency and maintaining emission uniformity across different viewing directions.
Solution Approach 2:
The light extraction block employs asymmetric geometry with non-uniform facet orientations and angles. This asymmetric design enables differential light extraction for different viewing zones, allowing the system to optimize both overall light extraction efficiency and angular emission uniformity by tailoring the optical path for each viewing direction.
2Loss of energy
If a truncated square-pyramid luminaire is used to enhance light extraction, then light extraction efficiency is improved, but color uniformity with viewing angle deteriorates
Solution Approach 1:
Different facets or regions of the light extraction block are assigned different local optical properties, such as varying reflectivity, refractive index, or surface microstructures. This local quality differentiation allows each region to optimize light extraction for its specific viewing zone while collectively maintaining overall color uniformity across all viewing angles.
Solution Approach 2:
The solution transitions from a two-dimensional planar emitting surface to a three-dimensional light extraction block with multiple facets and viewing zones. This dimensional expansion enables light to be extracted and emitted in multiple spatial directions simultaneously, improving both light extraction efficiency and color uniformity by distributing emission across three-dimensional space.
3Device complexity
If a planar emitting surface is used, then device simplicity is maintained, but light extraction efficiency deteriorates due to waveguiding
Solution Approach 1:
The light extraction block introduces curved or rounded surfaces instead of purely planar geometries. These curved surfaces disrupt the waveguiding effect by creating varying incident angles for trapped light modes, enabling more efficient light extraction while adding minimal structural complexity compared to a simple planar OLED device.
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
Improves light extraction efficacy, provides uniform emission intensity and color, and enhances illumination beyond the surface normal, while hiding imperfections and mixing colors effectively.
Implementation Method 1
light diffusing, or 'scattering,' layers on various emissive and/or other surfaces
Implementation Method 2
The luminaire includes sharply angled sides that extend at a relatively shallow acute angle, and are coated with a highly reflective material. Thus, the acutely angled sides and reflective material direct light towards the planar front surface
Implementation Method 3
coated with a highly reflective material. Thus, the acutely angled sides and reflective material direct light towards the planar front surface
Data Source
AI summary
Systems and methods for OLED lighting panels are provided in which a light extraction block is optically coupled to a light source. The light extraction block includes a plurality of non-parallel light emitting surface normals. At least one light diffusing layer covers a surface of the light extraction block. The light diffusing layer may be positioned, for example, on a light emitting surface of the light extraction block and/or on a mating surface of the light extraction block. The plurality of light emitting surface normals may be located on different non-parallel light emitting surfaces of the light extraction block, or on different points of a curved emitting surface. All of the light emitting surfaces and/or the mating surface, of the light extraction block may be covered by a light diffusing layer. The optical emission intensity and/or the optical emission color from the plurality of light emitting surface normals may be substantially equal.