Active Matrix Substrate Drain Electrode Extension Aperture Ratio
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in achieving a high aperture ratio while ensuring reliability, as previous technologies have limitations in optimizing light transmission and electric characteristics.
Innovation Solution
An active matrix substrate is designed with a conductive oxide semiconductor drain electrode extension section and a light-transmissive storage capacitor electrode, overlapping to enhance aperture ratio and reliability, featuring a production method that includes forming a storage capacitor electrode layer, gate insulating film layer, and conductive drain electrode extension section layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a pixel electrode is arranged to overlap with various wires and a film having a high transmittance is used as an interlayer insulating film, then the aperture ratio is increased, but the reliability is not sufficiently ensured
Solution Approach 1:
The drain electrode is segmented into two distinct parts: a conventional drain electrode and a newly added drain electrode extension section. This segmentation allows the extension section to specifically overlap with the storage capacitor electrode, creating a dedicated light transmission path that increases the aperture ratio without compromising the electrical reliability of the original drain electrode structure.
Solution Approach 2:
The drain electrode extension section is positioned in a different spatial dimension - it extends from the drain electrode to overlap with the storage capacitor electrode in the vertical stacking direction. This dimensional arrangement enables light to pass through the overlapping region, effectively increasing the aperture ratio while maintaining electrical functionality through the extended conductive path.
2Illumination intensity
If an oxide transparent film is used to increase aperture ratio, then light transmission is improved, but the electric characteristics and reliability are compromised
Solution Approach 1:
The material of the drain electrode extension section is changed to oxide semiconductor, which has different electrical parameters compared to conventional metals. This material parameter change enables the extension section to function as both a conductive element and a light-transmissive component, allowing it to overlap with the storage capacitor electrode without blocking light while maintaining sufficient electrical conductivity for reliable operation.
Solution Approach 2:
The drain electrode extension section uses oxide semiconductor material that combines properties of both conductors and transparent materials. This composite material approach allows the extension section to simultaneously provide electrical connectivity and light transmission, resolving the contradiction between improving aperture ratio through light transmission and maintaining reliable electric characteristics.
3Area of stationary object
If the drain electrode is extended to overlap with storage capacitor electrode, then aperture ratio is increased, but the manufacturing complexity increases
Solution Approach 1:
The formation of the drain electrode extension section is merged with the existing drain electrode formation process. By using the same oxide semiconductor material and formation steps for both the drain electrode and its extension, the patent avoids adding separate manufacturing processes, thereby increasing aperture ratio without proportionally increasing manufacturing complexity.
Solution Approach 2:
The oxide semiconductor material serves multiple functions: it acts as the drain electrode for electrical connectivity, extends to form the drain electrode extension section for light transmission, and can be formed using the same deposition process. This multi-functionality reduces the need for additional specialized manufacturing steps, keeping the process relatively simple while achieving higher aperture ratio.
Data Source
AI summary
The present invention provides a technology which allows ensuring a high level of reliability and achieving a high aperture ratio. An active matrix substrate includes: a drain electrode extension section connected to a drain electrode of a switching element and made of an oxide semiconductor which has been made conductive; and a storage capacitor electrode overlapping with at least a portion of the drain electrode extension section, at least a portion of the storage capacitor electrode being light-transmissive.