Organic Light-Emitting Display Device with Low Refractive Layer
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Solution Overview
Problem
Organic light-emitting display devices suffer from low cavity stability and emission efficiency due to variations in cavity length and light irradiation direction, leading to reduced output and internal quantum efficiency.
Innovation Solution
Incorporating a low refractive layer in specific areas of the organic light-emitting device and using a distributed Bragg reflector or a transparent electrode with a convex lens form to stabilize the micro-cavity structure and enhance light resonance and emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a micro-cavity structure is applied to an organic light-emitting device, then emission efficiency is enhanced, but cavity stability deteriorates due to variations in cavity length and light irradiation direction
Solution Approach 1:
The patent applies a convex lens form to the transparent electrode to create a curved micro-cavity structure. This curvature focuses light emission from the organic light-emitting layer, enhancing emission efficiency while maintaining stable cavity properties. The spherical/convex shape ensures consistent optical path lengths and stable resonance conditions, resolving the contradiction between enhanced emission and cavity stability.
2Productivity
If a distributed Bragg reflector is used, then light resonance is enhanced, but device complexity increases
Solution Approach 1:
The patent extracts the light resonance function from the complex distributed Bragg reflector structure and implements it through a simpler convex lens-shaped transparent electrode. This extraction maintains the essential light resonance and focusing benefits while eliminating the multi-layer complexity of traditional Bragg reflectors, thus enhancing light resonance without proportionally increasing device complexity.
3Device complexity
If the organic light-emitting layer is used without optimization, then device simplicity is maintained, but light output is reduced due to total internal reflection and surface plasmon resonance losses
Solution Approach 1:
The convex lens form of the transparent electrode creates a curved interface that reduces total internal reflection losses by optimizing light extraction angles. The curvature also minimizes surface plasmon resonance losses by altering the optical field distribution at the electrode interface. This maintains relative device simplicity while significantly reducing energy losses and improving light output.
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 solution increases cavity stability and emission efficiency by concentrating light and maximizing exciton distribution within the organic light-emitting layer, resulting in improved light output and reduced losses due to total internal reflection and surface plasmon resonance.
Implementation Method 1
a light-emitting layer on the first electrode, and a second electrode on the light-emitting layer, wherein an area in which the first electrode, the light-emitting layer, and the second electrode are sequentially stacked is defined as a pixel, and wherein the light-emitting layer includes a low refractive layer disposed in a first area in the pixel
Implementation Method 2
The term 'micro-cavity' denotes that light emitted from a light-emitting layer is amplified through repetitive reflection and re-reflection between an anode electrode and a cathode electrode to cause constructive interference
Implementation Method 3
light emitted from a light-emitting layer is amplified through repetitive reflection and re-reflection between an anode electrode and a cathode electrode to cause constructive interference
Implementation Method 4
using a distributed Bragg reflector or a transparent electrode with a convex lens form to stabilize the micro-cavity structure and enhance light resonance and emission efficiency
Implementation Method 5
when a high-level voltage is applied to the anode electrode and a low-level voltage is applied to the cathode electrode, a hole and an electron respectively move to the organic light-emitting layer through the hole transporting layer and the electron transporting layer, and are recombined with each other in the organic light-emitting layer to generate an exciton. Light having a particular wavelength is emitted according to energy being emitted from the generated exciton
Data Source
AI summary
An organic light-emitting display device includes: a first substrate, a first electrode on the first substrate, a light-emitting layer on the first electrode, and a second electrode on the light-emitting layer, wherein an area in which the first electrode, the light-emitting layer, and the second electrode are sequentially stacked is defined as a pixel, and wherein the light-emitting layer includes a low refractive layer disposed in a first area in the pixel.