Organic Light Emitting Display Recess Segmentation
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Solution Overview
Problem
In organic light emitting displays, particularly active matrix types, pixel driving failure can occur due to the shrinkage of planarization films, causing accidental connections between pixel regions and cathode-on-driver areas, which degrades display quality.
Innovation Solution
The implementation of a substrate with a pixel region and a non-pixel region, featuring a planarization layer, a pixel definition layer with openings, and a second pixel electrode extending over the non-pixel region, along with dummy patterns in recesses to reduce the depth of these recesses, preventing electrical connections and enhancing display stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a planarization layer is formed over the substrate to flatten the surface, then the surface flatness is improved, but the planarization layer shrinks during fabrication causing accidental connections between pixel region and non-pixel region
Solution Approach 1:
The patent introduces recesses that segment the planarization layer into isolated regions, preventing continuous electrical connection between pixel and non-pixel areas. The recesses create physical discontinuities in the planarization layer, ensuring electrical isolation even when the layer shrinks during fabrication.
Solution Approach 2:
The pixel definition layer acts as an intermediary barrier that fills the recesses and maintains electrical isolation. This layer is specifically positioned to prevent direct electrical connection between the first pixel electrode in the pixel region and the second pixel electrode extending into the non-pixel region, mediating the potential harmful electrical connection.
2Device complexity
If the second pixel electrode extends over the non-pixel region to cathode-on-driver area, then the device integration is improved, but accidental electrical connection with pixel region occurs causing pixel driving failure
Solution Approach 1:
The recesses segment the second pixel electrode's path, creating isolated sections that prevent continuous electrical connection to the pixel region. The electrode can extend into the non-pixel region for integration purposes, but the recesses ensure it cannot accidentally connect to the pixel region.
Solution Approach 2:
The harmful potential connection path is extracted by removing material to form recesses. This eliminates the continuous conductive path that would otherwise allow accidental electrical connection between the extended second pixel electrode and the pixel region.
3Reliability
If recesses are formed to prevent electrical connection, then electrical isolation is improved, but the depth of recesses may cause manufacturing difficulty
Solution Approach 1:
The pixel definition layer partially fills the recesses, providing sufficient electrical isolation without requiring complete filling. This partial action approach achieves the necessary isolation function while avoiding the manufacturing complexity of completely filling deep recesses.
Solution Approach 2:
The patent optimizes the depth and dimensions of the recesses to balance electrical isolation effectiveness with manufacturing feasibility. By carefully controlling the recess parameters, adequate isolation is achieved without creating excessively deep or complex structures that would be difficult to manufacture.
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 effectively prevents pixel driving failure and improves display quality by maintaining electrical isolation between pixel and cathode-on-driver regions, even with film shrinkage, ensuring consistent performance.
Implementation Method 1
electrons and holes are injected into an organic material through an anode and a cathode. The electrons and holes recombine with each other, and generate excitons. Light of a predetermined wavelength is generated by energy generated from the excitons.
Data Source
AI summary
An organic light emitting display and a method of fabricating the same are disclosed. One embodiment of the organic light emitting display includes a substrate including a pixel region and a cathode-on-driver (COD) region adjacent to the pixel region, a thin film transistor formed on the pixel region of the substrate, and a planarization film formed on an entire surface of the substrate to cover the thin film transistor. The organic light emitting display also includes an organic light emitting diode including a first pixel electrode formed on the planarization film and connected to the thin film transistor, an organic light emitting layer formed on the first pixel electrode, and a second pixel electrode formed on an entire surface of the substrate over the organic light emitting layer. The organic light emitting display further includes a pixel definition layer which is provided between the planarization film and the second pixel electrode. The pixel definition layer has an opening where the organic light emitting layer is located. Openings are formed through the planarization film and the pixel definition layer to provide a recess for separating the pixel region and the COD region from each other. The organic light emitting display further includes a conductive layer partially filling the recess for reducing the depth of the recess.