Dual Emission Layer OLED Structure With Resonant Intermediate Layer
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Solution Overview
Problem
Existing light-emitting elements for display devices face challenges in achieving improved luminous efficiency and service life, as they often rely on single light-emitting layers that struggle with secondary and tertiary resonance, leading to reduced performance.
Innovation Solution
A light-emitting element design featuring a first and second light-emitting layer with an intermediate layer of host material, optimized optical distances for secondary and tertiary resonance, and a bipolar intermediate layer to enhance electron and hole transport, improving luminous efficiency and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional single light emitting layer structure is used, then the device complexity is low, but the luminous efficiency and service life are insufficient
Solution Approach 1:
The light emitting element is divided into multiple light emitting layers (first light emitting layer and second light emitting layer) with different emission wavelengths. Each layer is segmented to emit light at specific wavelengths, allowing concurrent secondary and tertiary resonant light emission that improves luminous efficiency without excessive complexity
Solution Approach 2:
The patent introduces an intermediate layer with specific thickness (90-170 nm) that enables optical resonance in a new dimensional aspect. This intermediate layer creates optical path differences that facilitate secondary and tertiary resonances, adding an optical dimension to the layered structure to enhance efficiency
2Productivity
If the intermediate layer thickness is not optimized, then the manufacturing is easier, but the optical resonance efficiency is reduced
Solution Approach 1:
The patent optimizes the intermediate layer thickness parameter to a specific range (90-170 nm) to achieve optimal optical resonance. This parameter change enables the intermediate layer to create the necessary optical path differences for secondary and tertiary resonances, maximizing light emission efficiency while remaining manufacturable
3Use of energy by moving object
If only secondary resonance is implemented, then the structure is simpler, but the luminous efficiency is not maximized
Solution Approach 1:
The patent merges secondary resonance and tertiary resonance mechanisms into a single light emitting element structure. The intermediate layer is designed to enable both resonance types to operate concurrently, combining their effects to maximize luminous efficiency without requiring separate resonance mechanisms
Solution Approach 2:
The intermediate layer serves multiple functions: it acts as an optical spacer, enables secondary resonance for the first light emitting layer, enables tertiary resonance for the second light emitting layer, and facilitates charge transport between layers. This multi-functionality maximizes efficiency without proportionally increasing complexity
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 proposed design enhances luminous efficiency and service life by utilizing secondary and tertiary resonance, outperforming comparative examples with improved efficiency and extended service life across various wavelength ranges.
Implementation Method 1
the intermediate layer may have bipolar characteristics to transport electrons and holes
Implementation Method 2
the light-emitting element may produce excitons by recombining holes and electrons injected from a first electrode and from a second electrode, and emits light by lowering the state of the produced excitons to the ground state
Implementation Method 3
a distance from the upper surface of the first electrode to the lower surface of the first light emitting layer may be a first optical distance at which the first light secondarily resonates optically, and a distance from the upper surface of the first electrode to the lower surface of the second light emitting layer may be a second optical distance at which the second light tertiarily resonates optically
Data Source
AI summary
A light emitting element includes: a first electrode, a second electrode facing the first electrode, a first light emitting layer between the first electrode and the second electrode to emit a first light, a second light emitting layer between the first light emitting layer and the second electrode to emit a second light, and an intermediate layer including a host material between the first light emitting layer and the second light emitting layer and, wherein the intermediate layer has a thickness of from about 90 nm to 170 nm.