OLED Array Substrate Localized Gate Insulator Thickness
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Solution Overview
Problem
Existing OLED display devices manufacture thin-film transistors with the same structure, failing to meet the different electrical property requirements for switching and grayscale control functions.
Innovation Solution
An array substrate with distinct configurations for first and second thin-film transistors, utilizing indium gallium zinc oxide active channel layers and specific metal and insulating layer arrangements to achieve different sub-threshold characteristics, enabling quick switching and effective grayscale control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the same manufacturing procedure and structure are used for both thin-film transistors, then the manufacturing process is simple, but the different electrical property requirements for switching and grayscale control cannot be met
Solution Approach 1:
The patent applies local quality by making the gate insulating layer thickness local to each transistor's functional requirement. The first thin-film transistor (switching) has a 50-150nm gate insulating layer for fast switching, while the second thin-film transistor (grayscale control) has a 150-300nm gate insulating layer for stable grayscale regulation. This localized differentiation allows each transistor to have optimized electrical properties tailored to its specific function within the same device structure.
Solution Approach 2:
The patent implements parameter changes by varying the gate insulating layer thickness parameter between the two transistor types. By changing this critical dimensional parameter, the patent achieves different threshold voltages and electrical characteristics - the thinner layer in the first transistor enables fast switching with lower threshold voltage, while the thicker layer in the second transistor provides higher threshold voltage for stable grayscale control.
2Speed
If a thin gate insulating layer is used for fast switching, then switching speed is improved, but the transistor cannot provide stable grayscale control
Solution Approach 1:
The patent applies segmentation by dividing the gate insulating layer specification into two distinct segments: one for the first thin-film transistor (50-150nm) optimized for fast switching, and another for the second thin-film transistor (150-300nm) optimized for stable grayscale control. This segmentation allows each transistor type to have its gate insulating layer thickness independently optimized for its specific function, resolving the conflict between switching speed and grayscale stability.
3Reliability
If a thick gate insulating layer is used for stable grayscale control, then grayscale regulation is improved, but switching speed decreases
Solution Approach 1:
The patent applies local quality by making the gate insulating layer thickness local to each transistor's functional requirement. The first thin-film transistor (switching) has a 50-150nm gate insulating layer for fast switching, while the second thin-film transistor (grayscale control) has a 150-300nm gate insulating layer for stable grayscale regulation. This localized differentiation allows each transistor to have optimized electrical properties tailored to its specific function within the same device structure.
Data Source
AI summary
Disclosed are an array substrate of an OLED display device and a method for manufacturing the same. Thin-film transistors having different functions can have different electrical properties. The array substrate includes a base substrate, a semiconductor layer, a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, and a third insulating layer which are arranged sequentially from bottom to top. A plurality of driving units are formed on the array substrate, and each of the driving units comprises a first thin-film transistor and a second thin-film transistor.