Active Matrix Substrate Contact Hole Layout for LCD Light Leakage
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Solution Overview
Problem
Liquid crystal display devices, particularly in head-mounted displays, face challenges in achieving high contrast due to light leakage through contact holes during black display, which affects the luminance and overall display quality.
Innovation Solution
An active matrix substrate design that includes an oxide semiconductor layer with a novel structure where the pixel electrode and oxide semiconductor layer are connected via transparent extraction electrodes through contact holes, with specific configurations of the contact holes and extraction electrodes to minimize light leakage by controlling the polarization direction of transmitted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light-transmissive extraction electrodes are used to connect pixel electrode and oxide semiconductor layer, then electrical connection is achieved, but light leakage occurs during black display
Solution Approach 1:
The patent applies local quality by making the extraction electrode light-transmissive only in specific regions (where it overlaps with the oxide semiconductor layer) while maintaining light-blocking properties in other regions. This is achieved through selective positioning of the extraction electrode within the contact hole structure, allowing electrical connection where needed while preventing light leakage in critical areas.
Solution Approach 2:
The patent introduces an intermediary light-blocking layer that fills the contact hole and surrounds the extraction electrode. This light-blocking layer acts as a mediator that allows the extraction electrode to perform its electrical connection function while preventing light from passing through the contact hole during black display, thus resolving the contradiction between electrical connectivity and light leakage prevention.
2Ease of manufacture
If contact holes are made larger to facilitate electrode connection, then manufacturing is easier, but light leakage increases
Solution Approach 1:
The patent applies local quality by differentiating the optical properties of different regions within the contact hole structure. The extraction electrode is positioned to provide light-transmissive pathways only where electrical connection is required, while the light-blocking layer fills other regions to prevent light leakage. This allows adequate contact hole size for manufacturing while controlling light leakage through spatial differentiation of material properties.
Solution Approach 2:
The patent employs asymmetry in the contact hole structure by filling it with light-blocking material while leaving a controlled void space or positioning the extraction electrode asymmetrically within the hole. This asymmetric configuration allows the contact hole to be sufficiently large for electrode connection while ensuring that light-blocking material occupies the critical paths where light leakage would occur.
3Reliability
If extraction electrodes cover the entire contact hole, then electrical connection is improved, but polarization direction control is lost
Solution Approach 1:
The patent applies local quality by making the extraction electrode light-transmissive only in specific regions (where it overlaps with the oxide semiconductor layer) while maintaining light-blocking properties in other regions. This is achieved through selective positioning of the extraction electrode within the contact hole structure, allowing electrical connection where needed while preventing light leakage in critical areas.
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
The solution effectively suppresses light leakage during black display, enhancing the contrast and luminance of the liquid crystal display device, thereby improving the display quality, especially in high-resolution head-mounted displays.
Implementation Method 1
a portion of a side surface of at least one of the first contact hole and the second contact hole is not covered with the first extraction electrode and the second extraction electrode
Data Source
AI summary
An active matrix substrate includes a substrate and a plurality of pixels located on the substrate. Each of the pixels includes an oxide semiconductor layer, a first insulator covering the oxide semiconductor layer, a first contact hole located at the first insulator, a first extraction electrode located on the first insulator and in the first contact hole, and connected to the oxide semiconductor layer, a second insulator covering the first extraction electrode, a second contact hole located at the second insulator, a second extraction electrode located on the second insulator and in the second contact hole, and connected to the first extraction electrode, and a pixel electrode connected to the second extraction electrode. The first and second extraction electrodes are light-transmissive, and a portion of a side surface of at least one of the first and second contact holes is not covered with the first and second extraction electrodes.