Oxide TFT Active Layer Layout for Uniform Display Conductivity
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Solution Overview
Problem
The conductivity variation in metal oxide thin film transistors affects the resolution of display devices, limiting the design freedom and causing luminance non-uniformity, particularly in organic light emitting display devices.
Innovation Solution
Incorporating an inorganic pattern with high hydrogen content below the oxide-based active layer during a heat treatment process to enhance conductivity, allowing the active layer to function as wiring and improve design freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is applied to form active area and conductor region in metal oxide thin film transistor, then the active layer becomes conductive, but conductivity variation occurs which adversely affects display resolution
Solution Approach 1:
The patent applies local quality by introducing an inorganic pattern with high hydrogen content at specific locations (below the oxide-based active layer in the conductor region) to locally enhance conductivity. This targeted approach ensures uniform conductivity across the active layer while maintaining design freedom in the pixel circuit
Solution Approach 2:
The patent changes the chemical composition parameter by incorporating an inorganic pattern with high hydrogen content into the structure. This parameter change (hydrogen content) directly addresses the conductivity uniformity issue during heat treatment without requiring changes to the overall manufacturing process
2Reliability
If gate electrode is disposed on oxide-based active layer during heat treatment, then transistor structure is formed, but active layer conductivity is insufficient
Solution Approach 1:
The patent applies preliminary action by pre-positioning the inorganic pattern with high hydrogen content below the oxide-based active layer before heat treatment. This preliminary arrangement ensures that during subsequent heat treatment, hydrogen is released to enhance conductivity without requiring additional process steps
Solution Approach 2:
The inorganic pattern acts as an intermediary that facilitates hydrogen release during heat treatment. It mediates between the heat treatment process and the oxide-based active layer, enabling conductivity enhancement without direct contact between the gate electrode and active layer during processing
3Reliability
If inorganic pattern with high hydrogen content is disposed below oxide-based active layer, then conductivity is improved, but design freedom may be reduced
Solution Approach 1:
The patent resolves the contradiction by moving the inorganic pattern to a different spatial dimension (below the oxide-based active layer rather than above or within it). This dimensional relocation maintains design freedom for pixel circuit configuration while still achieving conductivity enhancement through hydrogen release during heat treatment
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 approach enhances conductivity, reduces luminance non-uniformity, and improves the reliability and resolution of display devices by increasing design freedom and space utilization.
Implementation Method 1
improving conductivity of the active layer, which overlaps an inorganic pattern, in a heat treatment process by disposing the inorganic pattern having high hydrogen content below an oxide-based active layer
Implementation Method 2
disposing the inorganic pattern having high hydrogen content below the oxide-based active layer
Data Source
AI summary
Provided is a display device. The display device comprises a first active layer disposed on a substrate and made of a first material, a second active layer disposed on the first active layer and made of a second material different from the first material, a first gate layer disposed on the second active layer, and an inorganic pattern disposed below the second active layer and overlapping a portion of the first gate layer. The second active layer includes a conductor portion disposed between a portion of the first gate layer and the inorganic pattern.