LCD Test Pad Layout for High Pixel Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the number of pixels in liquid crystal display (LCD) panels increases, the gap between test lines decreases, making it challenging to maintain sufficient size for test pads in the test area, which is essential for effectively testing and manufacturing the display panel.
Innovation Solution
The display panel design includes a test area with test pads and connecting lines formed from the same layer as the gate and data lines, allowing for efficient arrangement and testing, even as the pixel density increases, by using a specific layout where test pads are sufficiently large and connected through contact holes in the insulation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in LCD panels increases, then the pixel density and display resolution are improved, but the gap between test lines decreases making it difficult to maintain sufficient size for test pads
Solution Approach 1:
The patent extends test lines in both first and second directions to form a grid pattern, utilizing two-dimensional space instead of single-direction extension. This allows test pads to be connected through multiple pathways (first direction connection and second direction connection), effectively increasing the available area for test pads without increasing the linear dimensions of the test region.
Solution Approach 2:
The test lines are arranged in a nested grid structure where first direction test lines and second direction test lines intersect and overlap. Test pads are positioned at intersections, allowing multiple test lines to converge on a single test pad, thereby maximizing the utilization of limited test area while maintaining adequate test pad size.
2Measurement precision
If the number of pixels increases, then the display resolution is improved, but the test area becomes more constrained requiring more compact test pad arrangement
Solution Approach 1:
The test area is segmented into multiple test regions by dividing test lines into first direction test lines and second direction test lines. Each test pad connects to test lines in both directions, creating modular test units that can be independently configured. This segmentation allows efficient packing of test elements within the constrained test area.
Solution Approach 2:
Each test pad serves multiple functions by being connected to both first direction test lines and second direction test lines. A single test pad can test multiple test lines through the grid structure, and test lines can connect to multiple test pads, maximizing the utility of each test element within the limited test area.
Data Source
AI summary
A display panel includes first and second test lines connected to the each of data lines, extending in the second direction, and arranged in the first direction, a first test pad electrically connected to the first test line, the first test pad and the first test line being formed from a same layer, and a second test pad electrically connected to the second test line through a contact hole formed through a first insulation layer and disposed adjacent to the first test pad in the second direction.