Rectangular Contact Holes in Display Devices to Reduce Light Leakage
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Solution Overview
Problem
Existing display devices suffer from light leakage due to the large diameter of contact holes, which cause polarization cancellation and lower contrast.
Innovation Solution
The design incorporates contact holes with a rectangular shape aligned parallel to the polarization axis, reducing polarization cancellation and enhancing contrast by ensuring the contact holes do not overlap with light shielding layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact holes are made with a large diameter to ensure electrical connection, then electrical conductivity is improved, but light leakage occurs and contrast deteriorates
Solution Approach 1:
The contact hole is designed with an asymmetric rectangular shape rather than a circular shape. The rectangular shape has sides parallel and perpendicular to the polarization axis, creating asymmetry that allows the light shielding layer to effectively block light leakage while maintaining electrical connection. This asymmetric geometry enables the contact hole to align with the polarization direction, reducing polarization cancellation effects.
Solution Approach 2:
The contact hole structure is optimized locally by positioning it adjacent to the light shielding layer rather than overlapping it. The rectangular shape is specifically oriented so that its sides are parallel or perpendicular to the polarization axis, creating local geometric quality that minimizes light leakage in critical areas while maintaining electrical conductivity.
2Device complexity
If contact holes overlap with light shielding layers to simplify structure, then manufacturing complexity is reduced, but polarization cancellation occurs and contrast is lowered
Solution Approach 1:
The contact hole is extracted from the overlapping region with the light shielding layer and repositioned to be adjacent to it. This separation removes the harmful overlap that causes polarization cancellation while maintaining the necessary electrical connection function. The contact hole is taken out from the problematic position and placed in an optimized location next to the light shielding layer.
Solution Approach 2:
The rectangular contact hole is oriented asymmetrically with sides parallel and perpendicular to the polarization axis, positioned adjacent to rather than overlapping the light shielding layer. This asymmetric arrangement prevents polarization cancellation while maintaining structural simplicity.
3Object-affected harmful factors
If contact holes are made rectangular and aligned parallel to polarization axis to reduce polarization cancellation, then contrast is improved, but manufacturing precision requirements increase
Solution Approach 1:
The rectangular contact hole is designed with specific orientation where its sides are parallel or perpendicular to the polarization axis. This asymmetric orientation reduces polarization cancellation effects and improves contrast. The geometric asymmetry provides clear alignment references that can guide manufacturing processes.
Solution Approach 2:
The contact hole is positioned in a specific local region adjacent to the light shielding layer, with its rectangular shape oriented at a specific angle relative to the polarization axis. This local geometric quality optimization reduces the need for high-precision alignment across the entire device, as the critical orientation is localized to the contact hole geometry itself.
Data Source
AI summary
According to one embodiment, in a display device, each of a plurality of switching elements comprises a semiconductor layer, one scanning line on the semiconductor layer, one signal line provided in contact with a first portion of the semiconductor layer, a first insulating layer, a second insulating layer, and a first contact hole provided in the first insulating layer and the second insulating layer, and the one signal line is in contact with the first portion via the first contact hole, and the first contact hole is provided across the plurality of pixels and has a rectangular shape in plan view.