Capacitor Layer Separation in Display Devices
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Solution Overview
Problem
Existing display devices face limitations in improving performance due to the restriction of using a metal film in the same layer as the gate electrode for the capacitor, which hinders the enhancement of thin film transistor performance.
Innovation Solution
A display device configuration where the metal film constituting the capacitor is provided in a different layer from the transistor section, allowing for independent selection of materials and reducing resistance in the wiring layer, thereby improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a metal film in the same layer as the gate electrode is used for one electrode of the capacitor, then the device structure is simplified, but the thin film transistor performance improvement is restricted due to arrangement and material constraints
Solution Approach 1:
The patent applies dimensional separation by moving the capacitor electrode from the same layer as the gate electrode to a different layer (upper or lower layer). This layer separation allows independent optimization of the TFT structure and capacitor structure, enabling performance improvement without being constrained by the gate electrode's material and arrangement choices.
2Ease of manufacture
If the metal film for capacitor electrode is placed in the same layer as gate electrode, then manufacturing process is simplified, but wiring resistance cannot be reduced effectively
Solution Approach 1:
The invention resolves the wiring resistance issue by transitioning to a three-layer configuration where the capacitor electrode exists in a separate layer from the gate electrode. This allows the wiring layer to be optimized independently for low resistance without being constrained by the capacitor electrode's material requirements, enabling effective reduction of wiring resistance while maintaining manufacturing feasibility.
3Adaptability or versatility
If capacitor electrode shares the same layer as gate electrode, then material selection is restricted, but device complexity is reduced
Solution Approach 1:
The patent enables versatile material selection by creating an independent layer for the capacitor electrode. This separation allows different materials to be chosen for the gate electrode and capacitor electrode based on their respective functional requirements, without being forced to use the same material due to layer constraints, thereby enhancing adaptability and versatility.
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 enables higher performance by reducing wiring resistance and preventing delays, allowing for higher pixel density and faster drive capabilities, leading to improved image quality and performance.
Implementation Method 1
a gate insulating film, a semiconductor layer, and a gate electrode layer, the semiconductor layer being laminated on the gate insulating film, the gate electrode film being laminated on an opposite side to the semiconductor layer of the gate insulating film
Implementation Method 2
the second metal film being disposed over the first metal film with a first interlayer insulating film in between
Implementation Method 3
a first capacitor section that includes a first metal film and a second metal film, the first metal film being disposed at a same level as a wiring layer that is electrically connected to the semiconductor layer
Data Source
AI summary
A display device according to the present disclosure includes: a transistor section (100) that includes a gate insulating film (130), a semiconductor layer (140), and a gate electrode layer (120), the semiconductor layer being laminated on the gate insulating film, the gate electrode film being laminated on an opposite side to the semiconductor layer of the gate insulating film; a first capacitor section (200) that includes a first metal film (210) and a second metal film (220), the first metal film being disposed at a same level as wiring layers (161, 162) that are electrically connected to the semiconductor layer and is disposed over the transistor section, the second metal film being disposed over the first metal film with a first interlayer insulating film (152) in between; and a display element that is configured to be controlled by the transistor section.