Organic EL Light Extraction via Segmented Optical Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light-emitting devices with organic electroluminescence (EL) elements suffer from low total luminous flux and uneven emission due to internal light absorption and reflection, limiting their efficiency and effectiveness.
Innovation Solution
The design incorporates a structure with a first and second electrode, each comprising a light-transmitting and light-reflecting conductive film, and optical structure bodies on opposite substrates to optimize light extraction, reducing internal reflection and enhancing emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an optical structure body with diameter greater than the light-emitting portion is provided to increase light extraction, then the amount of light emitted outside is increased, but the installation area is reduced and light is totally reflected at the interface
Solution Approach 1:
The optical structure body is divided into multiple segments arranged in an array, where each segment has a diameter smaller than the light-emitting portion. This segmentation allows light to be extracted through multiple distributed points rather than requiring a single large optical structure, thereby maintaining installation area while achieving sufficient total luminous flux extraction.
Solution Approach 2:
The patent applies optical structure bodies at specific locations where light extraction is most beneficial, rather than uniformly across the entire light-emitting portion. By strategically positioning multiple smaller optical structures, the solution optimizes light extraction in critical areas while preserving installation area in other regions.
2Productivity
If a single optical structure body is used to extract light, then the device structure is simple, but light extraction efficiency is reduced due to total internal reflection
Solution Approach 1:
The optical structure body is segmented into multiple smaller optical elements arranged in an array. Each segment independently extracts light from the light-emitting portion, collectively achieving superior light extraction efficiency compared to a single optical structure, while maintaining manageable device complexity through modular configuration.
Solution Approach 2:
The patent transitions from a single-point optical extraction approach to a distributed array configuration, effectively moving from zero-dimensional (single point) to two-dimensional (array distribution) light extraction. This dimensional change enables parallel light extraction paths, significantly improving overall extraction efficiency without excessive complexity increase.
3Loss of energy
If the optical structure body diameter is increased to reduce guided wave generation, then light extraction is improved, but the installation area occupied is increased
Solution Approach 1:
The large-diameter optical structure is segmented into multiple smaller-diameter optical elements. Each small optical element effectively reduces guided wave generation at its interface while occupying minimal installation area. The collective array of these segments achieves total light extraction comparable to or exceeding that of a single large optical structure, with significantly reduced total installation area footprint.
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
This configuration significantly increases the total luminous flux and reduces emission unevenness, leading to a more efficient and effective light-emitting device with lower power consumption.
Implementation Method 1
light (also referred to as guided wave in the substrate mode) traveling in the plane direction while being totally reflected in a substrate are generated
Implementation Method 2
the angle of light entering the optical structure body and an interface of an air layer is increased (that is, the light substantially enters perpendicularly)
Implementation Method 3
a first electrode and a second electrode which sandwich an organic EL layer and a setting position of an optical structure body provided on a substrate are devised
Implementation Method 4
each comprising a light-transmitting and light-reflecting conductive film
Implementation Method 5
an element utilizing organic electroluminescence (EL)
Data Source
AI summary
An organic EL light-emitting device with excellent total luminous flux or with reduced emission unevenness and low power consumption is provided. Light from an organic EL layer in a region sandwiched between a light-transmitting conductive film of a lower electrode and a light-reflecting conductive film of an upper electrode is selectively emitted to the lower electrode side, and extracted outside by a first optical structure body. Light from the organic EL layer in a region sandwiched between a light-reflecting conductive film of the lower electrode and a light-transmitting conductive film of the upper electrode is selectively emitted to the upper electrode side, and extracted outside by a second optical structure body. The first optical structure body and the second optical structure body are formed on different planes and can overlap with each other; thus, light from the organic EL layer can be efficiently extracted outside.