Display Device Conductive Pattern Thickness Optimization
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Solution Overview
Problem
Existing display devices face challenges in efficiently controlling threshold voltages of transistors and improving light emission efficiency due to limitations in the design of conductive patterns and transistor structures.
Innovation Solution
A display device with a conductive pattern that includes an electrode portion and a wiring portion, where the wiring portion is thicker than the electrode portion, and the conductive pattern is positioned between the substrate and the active pattern of transistors, allowing for controlled voltage supply and improved transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive pattern uses a uniform thickness for both electrode portion and wiring portion, then the manufacturing process is simpler, but the voltage supply efficiency and transistor threshold voltage control are insufficient
Solution Approach 1:
The conductive pattern is designed with different thicknesses for different portions: the electrode portion has a first thickness optimized for capacitance coupling with the transistor active pattern, while the wiring portion has a second thickness optimized for voltage transmission. This local differentiation allows each portion to perform its specific function optimally without compromising the other.
Solution Approach 2:
The conductive pattern is segmented into distinct portions (electrode portion and wiring portion) with different thickness characteristics. This segmentation allows independent optimization of each portion's properties - the electrode portion for effective voltage application to the transistor, and the wiring portion for efficient voltage supply from the external circuit.
2Reliability
If the wiring portion has greater thickness than the electrode portion, then voltage supply efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The thickness parameter of the conductive pattern is changed across different spatial locations to achieve different functional requirements. The wiring portion uses a greater thickness parameter to minimize resistance and improve voltage supply efficiency, while the electrode portion uses a controlled thickness parameter to achieve optimal capacitance coupling with the transistor active pattern.
3Reliability
If the electrode portion overlaps the active pattern of transistors, then threshold voltage control is improved, but the device area increases
Solution Approach 1:
The electrode portion is positioned in a different vertical dimension (z-axis) relative to the active pattern, overlapping it in the planar view but separated by insulating layers. This three-dimensional arrangement allows the electrode to effectively couple with the active pattern for threshold voltage control without increasing the horizontal footprint of the pixel circuit.
Data Source
AI summary
A display device including: a substrate; a light emitting element on the substrate; a pixel circuit between the substrate and the light emitting element, wherein the pixel circuit is electrically connected to the light emitting element, and includes a plurality of transistors; and a conductive pattern including an electrode portion and a wiring portion for supplying a voltage to the electrode portion, wherein the electrode portion overlaps an active pattern of at least one transistor among the plurality of transistors, wherein the conductive pattern is disposed between the substrate and the active pattern, and wherein a thickness of the wiring portion is greater than a thickness of the electrode portion.