Array Substrate Insulation Layout for TFT Impurity Blocking
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Solution Overview
Problem
In organic light emitting display devices, impurities such as moisture from the organic layer can pass through transparent electrode material and spread to the active layer, affecting the characteristics of thin film transistors.
Innovation Solution
The array substrate includes a semiconductor section covered by multiple insulation films, with the first and second insulation films made of inorganic materials and the third insulation film made of organic material, featuring specific contact holes to connect electrodes while minimizing impurity penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent electrode material is used for the source/drain electrode, then light transmittance is improved, but impurities such as moisture can pass through and spread to the active layer
Solution Approach 1:
An inorganic insulation film is introduced as an intermediary layer between the organic layer and the transparent source/drain electrode. This inorganic film acts as a barrier that blocks impurities like moisture from passing through the transparent electrode to the active layer, while maintaining the light transmittance property of the transparent electrode material.
Solution Approach 2:
The structure combines organic insulation material and inorganic insulation material in a layered configuration. The organic layer provides insulation and the inorganic layer provides impurity barrier functionality, creating a composite structure that simultaneously achieves both light transmittance and impurity protection.
2Object-affected harmful factors
If multiple insulation films are added to block impurities, then impurity spread is reduced, but device complexity increases
Solution Approach 1:
The inorganic insulation film is selectively positioned only in the region where impurity blocking is most critical - between the organic layer and the transparent source/drain electrode. This localized approach provides effective impurity protection without adding insulation films throughout the entire device structure, thereby limiting the increase in device complexity.
Data Source
AI summary
An array substrate includes a semiconductor section, a first insulation film in a layer upper than the semiconductor section, a first electrode in a layer upper than the first insulation film and overlapping the semiconductor section, a second insulation film in a layer upper than the first electrode, and a third insulation film in a layer upper than the second insulation film. The first electrode is made of transparent electrode material. The first insulation film is made of inorganic insulation material and includes a first contact hole in a portion overlapping the semiconductor section and the first electrode, and the semiconductor section and the first electrode are connected via the first contact hole. The third insulation film is made of organic insulation material. The second insulation film is made of inorganic insulation material and covers at least a first overlapping portion of the first electrode overlapping the first contact hole.