Organic EL Device Smoothening Layer for Flexible Substrates
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Solution Overview
Problem
Existing organic electroluminescence devices face challenges with flexibility, high production costs due to glass substrates, and low yield rates and light-extraction efficiency due to surface roughness and plasmon absorption issues with metal substrates.
Innovation Solution
An organic electroluminescence device design featuring a smoothening layer between a reflective metal layer and the first electrode, with the reflective metal layer acting as an auxiliary electrode and an intermediate insulating layer to prevent short-circuits and enhance light extraction, using a flexible substrate like a polymer film or metal foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a metal substrate is used as a flexible substrate, then flexibility and cost are improved, but surface roughness causes short-circuits between electrodes, lowering yield rate
Solution Approach 1:
A smoothening layer is introduced as an intermediary between the metal substrate and the electrode. This smoothening layer has a smooth surface that prevents short-circuits between electrodes while allowing the metal substrate to maintain its flexibility and cost advantages.
Solution Approach 2:
The device structure is segmented into distinct functional layers: the metal substrate provides flexibility, the smoothening layer provides surface smoothness, and the electrode provides electrical conductivity. This segmentation allows each layer to optimize its specific function without compromising the others.
2Manufacturing precision
If the surface of metal substrate is smoothened by mirror-polishing or SOG technique, then short-circuit prevention is improved, but manufacturing complexity increases and mass production becomes difficult
Solution Approach 1:
Instead of using complex and expensive mirror-polishing or SOG techniques, a simple smoothening layer is applied that can be deposited using conventional, cost-effective manufacturing processes. This layer provides the necessary surface smoothness without requiring complex equipment or multi-step procedures.
Solution Approach 2:
The approach changes the parameter of surface smoothness from being achieved through mechanical processing (mirror-polishing) or complex coating (SOG) to being achieved through a dedicated smoothening layer with controlled surface properties, simplifying the manufacturing process.
3Manufacturing precision
If electroless plating layer is formed on metal substrate, then surface smoothness is improved, but light-extraction efficiency is lowered due to plasmon absorption
Solution Approach 1:
The harmful electroless plating layer that causes plasmon absorption is removed or replaced. Instead, a smoothening layer is used that provides surface smoothness without the plasmon absorption problem, thereby extracting the beneficial surface smoothness while eliminating the harmful energy loss.
Solution Approach 2:
The original electroless plating layer had dual effects: it smoothed the surface (benefit) but caused plasmon absorption (harm). The invention separates these functions by using a different material for the smoothening layer that provides surface smoothness without causing plasmon absorption, converting the harmful effect into a beneficial one.
4Ease of manufacture
If functional layer is directly laminated on electroless plating layer, then manufacturing simplicity is improved, but light-extraction efficiency is lowered due to surface plasmon absorption
Solution Approach 1:
A smoothening layer is introduced as an intermediary between the metal substrate and the functional layer. This layer provides surface smoothness for easy manufacturing while avoiding the plasmon absorption problem that occurs when the functional layer is directly laminated on the electroless plating layer.
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 design improves yield rates and light-extraction efficiency by reducing surface roughness-induced short-circuits and plasmon absorption, while allowing for flexible and cost-effective large-area organic EL devices.
Implementation Method 1
a smoothening layer is formed partially between the reflective metal layer and the first electrode
Implementation Method 2
a reflective metal layer
Implementation Method 3
the reflective metal layer and the first electrode are electrically conductive to each other at a region where the smoothening layer is not formed
Implementation Method 4
an organic compound layer including an emitting layer
Data Source
AI summary
An organic electroluminescence device includes: a first substrate; a reflective metal layer; a first electrode; an organic compound layer; and a second electrode, which are disposed in this sequence. The first substrate is provided by at least one of a metal film, a metal plate, a polymer film, a polymer plate, a polymer film with a damp-proof film, and a polymer plate with a damp-proof film. A smoothening layer is formed partially between the reflective metal layer and the first electrode. The reflective metal layer and the first electrode are electrically conductive to each other at a region where the smoothening layer is not formed.