Variable Width Metal Line for LCD Alignment Error Tolerance
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Solution Overview
Problem
In liquid crystal display devices, alignment errors between common electrodes and metal lines during the manufacturing process lead to inaccurate electrical connections, reducing yield and affecting display quality.
Innovation Solution
The display device design includes metal lines with specific portions that partially overlap the common electrode and data lines, where the first portion has a greater width along the data line direction and the second portion overlaps the data line, preventing alignment errors and enhancing electric field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal lines are designed with uniform width to simplify manufacturing, then manufacturing precision is improved, but alignment error between common electrodes and metal lines increases, reducing electrical connection accuracy
Solution Approach 1:
The metal line is designed with different widths in different regions: a first width in the first region overlapping the common electrode, and a second width in the second region overlapping the data line. This local differentiation allows the metal line to accommodate alignment errors while maintaining manufacturing simplicity, thereby improving electrical connection accuracy without compromising fabrication consistency.
2Reliability
If metal line width is increased to ensure overlap with common electrode, then electrical connection reliability is improved, but RC loading on data lines increases, reducing signal transmission performance
Solution Approach 1:
The metal line width is locally optimized: wider in the first region overlapping the common electrode to ensure reliable electrical connection, and narrower in the second region overlapping the data line to minimize RC loading. This spatially varying width design simultaneously achieves both connection reliability and signal transmission efficiency.
3Reliability
If metal line overlaps common electrode more extensively, then alignment error tolerance is improved, but electric field intensity control deteriorates, affecting liquid crystal molecule tilt
Solution Approach 1:
The metal line is designed with a wider first width in the first region to provide alignment error tolerance, while the second width in the second region is optimized to maintain proper electric field intensity control. The localized width adjustment ensures that alignment tolerance is enhanced without compromising electric field control in critical regions.
Data Source
AI summary
A display device is disclosed, which includes: a first substrate; a common electrode disposed on the first substrate; a metal line electrically connecting to the common electrode and extending along a first direction, wherein the metal line comprises a first region, and the first region at least partially overlaps the common electrode; and a light shielding region, wherein a part of the light shielding region extends along the first direction and at least covers the metal line, wherein the first region has a first maximum width along a second direction vertical to the first direction, the metal line has a metal edge closest to a shielding edge of the light shielding region, the shielding edge extends along the first direction, and along the second direction, a minimum distance between the shielding edge and the metal edge is between 0 μm and the first maximum width.