Thin-Film Transistor Array Substrate Static Charge Discharge
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Solution Overview
Problem
Conventional thin-film transistor array substrates are vulnerable to overcharge bursts due to static electricity, particularly in the active layers, which can lead to defective spots and poor image quality in organic light-emitting display devices.
Innovation Solution
The solution involves forming a data-line and light-blocking pattern on the substrate before creating the active layer, with connecting patterns that allow charge discharge during the patterning process, thereby preventing overcharge bursts. This includes forming a buffer insulating film, gate insulating film, and specific contact holes to connect the active layer to the data-line and light-blocking pattern, ensuring the active layer is not exposed to excessive static charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate electrode is disposed on a gate insulating-film covering at least a portion of the active layer to reduce leakage current, then the leakage current is reduced, but the active layer is exposed to the patterning process and vulnerable to overcharge burst from static electricity
Solution Approach 1:
A charge discharge pattern is introduced as an intermediary element between the active layer and the patterning process. This pattern provides a controlled discharge path for static charges that accumulate during gate electrode patterning, preventing overcharge bursts while allowing the gate insulating film to maintain its leakage current reduction function
Solution Approach 2:
The electrical parameters of the active layer are changed by introducing a charge discharge mechanism. Instead of maintaining the active layer in an isolated state, a controlled discharge path is created that dynamically manages charge accumulation, transforming the electrical behavior to prevent overcharge bursts
2Area of stationary object
If the width of the active layer is increased, then the pixel region coverage is improved, but the amount of charges charged in the active layer increases, making it more vulnerable to overcharge burst
Solution Approach 1:
The charge discharge pattern serves as an intermediary that scales with the active layer area. As the active layer width increases, the charge discharge pattern proportionally increases its discharge capacity, maintaining a balanced charge management system that prevents overcharge bursts regardless of active layer size
3Ease of manufacture
If the active layer is exposed during the patterning process, then the gate electrode can be formed, but static electricity causes charge accumulation leading to defective spots
Solution Approach 1:
The charge discharge pattern is formed in advance during the patterning process, creating a pre-established discharge path before static charge accumulation becomes problematic. This preliminary action ensures that when charges do accumulate during gate electrode formation, they can be immediately discharged through the pre-positioned pattern
Solution Approach 2:
The charge discharge pattern acts as an intermediary safety mechanism that allows the patterning process to proceed normally while simultaneously providing protection against manufacturing defects caused by static electricity
Data Source
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AI summary
An organic light-emitting diode (OLED) device includes an active layer of a transistor disposed on the buffer insulating film. A gate insulating film is disposed on the buffer insulating film over the conducting layer and disposed on the active layer. A gate electrode is disposed on the gate insulating film over a channel region of the active layer. A first connecting pattern is disposed on the gate insulating film over the conducting line and the active layer. The first connecting pattern is connected to the conducting layer via a first connecting contact hole through the gate insulating film and the buffer insulating film. The first connecting pattern is also connected to the active layer via a second connecting contact hole through the gate insulating film. The first connecting pattern has a same material as the gate electrode.