OLED Pixel Electrode Layout for Low-Reflectance Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display apparatuses face issues with external light reflectance, which can degrade image visibility and increase thickness when polarization layers are used to mitigate this problem, leading to decreased light efficiency.
Innovation Solution
The display apparatus includes a substrate with a pixel circuit, a bridge electrode, and a pixel electrode structure where the bridge electrode overlaps the opening of the pixel definition layer and is electrically connected through a contact hole, using transparent conductive oxides to minimize external light reflectance without increasing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarization layer is added to reduce external light reflectance, then image visibility is improved, but the thickness of the display apparatus increases and light efficiency decreases
Solution Approach 1:
The patent extracts the light-blocking function from a separate polarization layer and integrates it into the pixel electrode structure itself. The pixel electrode is designed to extend into the contact hole region, creating an integrated structure that blocks external light without requiring an additional polarization layer, thereby reducing overall device thickness while maintaining anti-reflection performance
Solution Approach 2:
The patent merges the pixel electrode and bridge electrode into a single integrated structure where the pixel electrode extends to overlap with the contact hole. This combination integrates multiple functions (electrical connection and light blocking) into one structure, eliminating the need for separate polarization layers and reducing device thickness
2Object-affected harmful factors
If a polarization layer is added to reduce external light reflectance, then image visibility is improved, but light efficiency decreases
Solution Approach 1:
The patent extracts the light-blocking function from a separate polarization layer and integrates it into the pixel electrode structure. By positioning the pixel electrode to overlap the contact hole, external light is blocked at the source without adding a polarization layer that would absorb or reflect emitted light, thereby maintaining high light efficiency
Solution Approach 2:
The pixel electrode serves as an intermediary structure that performs dual functions: providing electrical connection through the contact hole and blocking external light. This intermediary structure eliminates the need for a separate polarization layer, preventing light efficiency loss while still reducing external light reflectance
3Ease of manufacture
If the pixel electrode overlaps the contact hole, then electrical connection is simplified, but external light reflectance increases
Solution Approach 1:
The patent uses a planar overlap configuration in the top view where the pixel electrode extends to cover the contact hole area. This two-dimensional arrangement allows the electrode to make electrical contact through the contact hole while simultaneously blocking external light from reaching reflective interfaces, resolving the contradiction between electrical connection and light reflection
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 reduces external light reflectance at the surface of the display apparatus, maintaining image clarity and efficiency while avoiding the need for thick polarization layers.
Implementation Method 1
the bridge electrode may include a transparent conductive oxide
Data Source
AI summary
Provided are a display apparatus including: a substrate; a pixel circuit disposed over the substrate and comprising a thin film transistor and a storage capacitor; an insulating layer covering the pixel circuit; a bridge electrode disposed over the insulating layer and electrically connected to the pixel circuit through a contact hole formed in the insulating layer; a pixel electrode disposed over the insulating layer and electrically connected to the bridge electrode; a pixel definition layer disposed over the pixel electrode and including an opening overlapping a portion of the pixel electrode; an opposite electrode over the pixel electrode; and an emission layer disposed between the pixel electrode and the opposite electrode, wherein the pixel electrode does not overlap the contact hole of the insulating layer in a plan view.