OLED Pixel Semiconductor Layout for Misaligned Contact Holes
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Solution Overview
Problem
In high-resolution OLED displays, the shrinking pixel size leads to increased defects due to misaligned contact holes, causing non-uniform lighting between adjacent pixels and potential disconnection of semiconductor members.
Innovation Solution
The OLED display design incorporates a non-linear semiconductor layer with expansion semiconductor parts and metal lines having wider sections at contact holes to prevent disconnection and ensure stable current flow, using a 7Tr-2Cap structure with transistors and capacitors for each pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to increase resolution, then the display resolution is improved, but the alignment precision deteriorates leading to etchant penetration and semiconductor disconnection
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the semiconductor layer before the etching process. This protective film is strategically positioned to cover the semiconductor layer at contact hole locations, preventing etchant from penetrating and damaging the semiconductor layer during subsequent etching operations. The protective film is formed in advance to anticipate and prevent the alignment error problem that occurs at high resolutions.
Solution Approach 2:
The patent implements beforehand cushioning by creating a buffer protective film that absorbs or mitigates the harmful effect of misalignment. The protective film acts as a cushion between the etchant and the semiconductor layer, preventing the etchant from directly contacting and damaging the semiconductor layer even when alignment errors occur during the etching process.
2Ease of manufacture
If contact holes are formed with standard alignment, then the manufacturing process is simple, but alignment errors cause etchant penetration and pixel non-uniformity
Solution Approach 1:
The protective film is formed on the semiconductor layer before the contact hole etching process begins. This preliminary action ensures that even if alignment errors occur during etching, the semiconductor layer is already protected and cannot be penetrated by the etchant, thereby maintaining pixel lighting uniformity without complicating the manufacturing process.
Solution Approach 2:
The protective film serves as an intermediary layer between the etchant and the semiconductor layer. It mediates the interaction by blocking the etchant from directly contacting the semiconductor layer, thus preventing damage and ensuring reliable pixel lighting uniformity while allowing the standard contact hole formation process to continue.
3Reliability
If the semiconductor layer width is increased to prevent disconnection, then the reliability is improved, but the pixel area decreases affecting resolution
Solution Approach 1:
The patent applies segmentation by separating the protective function from the conductive function. The protective film is a distinct layer that provides protection without requiring the semiconductor layer itself to be wider. This allows the semiconductor layer to maintain its original narrow width for high resolution while the separate protective film layer provides the necessary protection against etchant penetration.
Solution Approach 2:
The protective film acts as an intermediary that provides the protective function without requiring changes to the semiconductor layer dimensions. It mediates between the need for narrow semiconductor lines (for high resolution) and the need for protection against etchant penetration (for reliability), allowing both requirements to be satisfied 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 design prevents non-uniform lighting and maintains pixel functionality by ensuring stable current paths, enhancing display quality and resolution in high-resolution OLEDs.
Implementation Method 1
Electrons injected from a cathode electrode and holes injected from an anode electrode are bonded to each other in the organic light emitting layer to form excitons. Light is emitted while the excitons discharge energy.
Data Source
AI summary
An organic light-emitting diode display is disclosed. In one aspect, a semiconductor layer is on a substrate, and the semiconductor layer is non-linear. A gate metal line is on the semiconductor layer, and an insulating layer covering the semiconductor layer and the gate metal line and having a plurality of contact holes connected to the semiconductor layer. A data metal line is on the insulating layer and electrically connected to the semiconductor layer via a selected one of the contact holes. An OLED is electrically connected to the gate metal line and the data metal line, and the semiconductor layer includes a narrow semiconductor layer having a first width and an expansion semiconductor layer formed adjacent to the selected contact hole and having a second width greater than the first width.