OLED Pixel Electrode Inclined Surface Light Extraction
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Solution Overview
Problem
Organic light emitting display apparatuses face inefficiencies in light extraction due to total reflection between layers, leading to reduced light emission and lower resolution.
Innovation Solution
The design includes a pixel definition layer with inclined parts and a reflective opposite electrode, along with separate light emitting and extraction regions, to enhance light reflection and emission efficiency, minimizing total reflection and increasing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional planar pixel electrode structure is used, then the device structure is simple, but light extraction efficiency is reduced due to total reflection between layers
Solution Approach 1:
The pixel electrode is designed with an inclined surface instead of a planar structure. The inclination angle is specifically optimized to redirect reflected light toward the light extraction region, converting harmful total reflection into useful light output and improving light extraction efficiency.
Solution Approach 2:
The pixel electrode structure transitions from a two-dimensional planar surface to a three-dimensional inclined surface. This dimensional change introduces a new geometric parameter (inclination angle) that enables effective light redirection and extraction without complicating the manufacturing process.
2Illumination intensity
If the aperture ratio is increased to improve light emission, then light extraction efficiency improves, but resolution deteriorates due to reduced pixel density
Solution Approach 1:
The inclined surface is applied locally to the pixel electrode rather than uniformly across the entire display. This localized structural modification allows light extraction enhancement in specific regions without affecting the overall pixel density and resolution of the display apparatus.
Solution Approach 2:
The display surface is segmented into distinct functional regions: light emitting regions with inclined pixel electrodes for high light extraction, and light extraction regions for light output. This segmentation allows optimization of each region's function without compromising overall resolution.
3Loss of energy
If light extraction regions are added to improve light emission, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The pixel definition layer serves multiple functions: it defines pixel boundaries, creates the inclined surface geometry for light redirection, and forms part of the light extraction region structure. This multi-functionality reduces the need for additional separate components, maintaining device simplicity while improving light extraction.
Solution Approach 2:
The light extraction function is merged into the existing pixel electrode and pixel definition layer structures rather than being implemented as a separate component. The inclined pixel electrode surface and pixel definition layer work together to achieve both pixel definition and light extraction functions simultaneously.
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 improves light extraction efficiency, reduces light loss, and increases the resolution of the organic light emitting display apparatus by ensuring all emitted light is directed outside through specific extraction regions.
Implementation Method 1
a first pixel electrode and a second pixel electrode on a substrate and spaced apart from each other, and each including a reflective layer... an opposite electrode on the first intermediate layer, the second intermediate layer and the pixel definition layer, and including a reflective layer
Data Source
AI summary
An organic light emitting display apparatus includes: a first pixel electrode and a second pixel electrode on a substrate and spaced apart from each other, each of the first pixel electrode and the second pixel electrode including a reflective layer; a pixel definition layer extending between and overlapping adjacent edges of the first pixel electrode and the second pixel electrode; a first intermediate layer and a second intermediate layer respectively on the first pixel electrode and the second pixel electrode; and an opposite electrode on the first intermediate layer, the second intermediate layer and the pixel definition layer and including a reflective layer.