OLED Light Directing Structure for High Luminance
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Solution Overview
Problem
Phosphorescent organic light emitting diodes (PHOLEDs) face challenges in achieving high luminance for general lighting applications, requiring current densities greater than 1 mA/cm2, which reduces device lifetime and efficiency, and existing solutions for uniform light distribution increase cost and complexity.
Innovation Solution
A luminaire device with a base and organic light emitting diodes (OLEDs) arranged in a light directing structure, where each OLED has a reflective surface to concentrate light towards a light exit aperture, increasing luminance and achieving uniform surface illuminance through a batwing intensity profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current density is increased to achieve high luminance for general lighting applications, then luminance is improved, but device lifetime and efficiency deteriorate
Solution Approach 1:
The patent segments the light emitting function from the light concentrating function by using multiple individual OLEDs arranged in a light directing structure. Each OLED operates at low current density while the macrostructure concentrates their combined output, resolving the contradiction between luminance and device lifetime
Solution Approach 2:
The patent transitions from a single-plane OLED to a three-dimensional light directing structure with multiple OLEDs positioned at different locations and angles. This dimensional expansion allows light concentration without increasing individual OLED current density, maintaining efficiency while achieving high luminance
2Illumination intensity
If current density is increased to achieve high luminance, then luminance is improved, but efficiency deteriorates
Solution Approach 1:
The patent introduces reflective surfaces as intermediaries between the OLEDs and the light exit aperture. These reflectors redirect and concentrate light that would otherwise be lost, improving energy efficiency while maintaining high luminance output without increasing current density
3Stability of the object's composition
If existing solutions for uniform light distribution are used, then uniform illuminance is improved, but cost and device complexity increase
Solution Approach 1:
The patent employs asymmetric light directing structures with specific geometric arrangements of OLEDs and reflective surfaces. This asymmetric design naturally produces uniform illuminance through controlled light redirection paths, achieving uniformity without complex additional components
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 enhances directional light concentration, increasing luminance by approximately three times and providing a uniform illuminance pattern suitable for general lighting, while maintaining efficiency and reducing operational costs.
Implementation Method 1
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Implementation Method 2
Each OLED can include a reflective surface that is disposed to direct light output by each OLED towards the light exit aperture
Data Source
AI summary
Embodiments of the disclosed subject matter provide a device with a base having an opening, and a plurality of organic light emitting devices (OLEDs) disposed on a plurality of substrates and arranged in a light directing structure onto the base, where the opening of the base is a light exit aperture of light output by the plurality of OLEDs.