Demux Test Line Layout for Narrow-Bezel OLED Displays
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Solution Overview
Problem
The challenge of reducing the width of the non-display area in display devices without compromising resolution or increasing short-circuit defects due to the increase in the number of connection lines and reduced distance between them.
Innovation Solution
The implementation of demultiplexer (demux) circuit units and test signal supply lines in the non-display area, along with test pad connection lines and contact holes, which allow for a more efficient electrical connection between data lines and the display driving circuit, reducing the width of the non-display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of data lines is increased to improve resolution, then the resolution is improved, but the width of the non-display area increases due to more connection lines
Solution Approach 1:
The patent divides the non-display area into multiple regions and segments the connection lines into different layers. By distributing connection lines across multiple layers and regions, the patent reduces the width required for connection lines in any single region, thereby reducing the overall width of the non-display area while maintaining high resolution capabilities
Solution Approach 2:
The patent utilizes multiple layers (vertical dimension) to route connection lines instead of confining all connection lines to a single plane. This multi-layer approach allows connection lines to be stacked vertically, reducing the horizontal width requirement of the non-display area while supporting increased data line counts for higher resolution displays
2Area of stationary object
If the width of the non-display area is reduced to increase the proportion of display area, then the display area proportion is improved, but the distance between connection lines is reduced increasing short-circuit defects
Solution Approach 1:
By routing connection lines through multiple layers with sufficient vertical spacing, the patent maintains adequate isolation between adjacent connection lines even when the horizontal distance is reduced. This multi-layer configuration allows the non-display area width to be minimized while preserving reliability by preventing short-circuit defects through proper layer-to-layer spacing and insulation
Solution Approach 2:
The patent introduces intermediate structures such as insulating layers and spacing elements between connection lines in the multi-layer configuration. These intermediary elements maintain electrical isolation between adjacent connection lines, enabling reduced spacing without increasing short-circuit risks, thus allowing smaller non-display area widths
Data Source
AI summary
A display device includes a substrate, a circuit layer, a light emitting element layer, and a display driving circuit. The circuit layer comprises demux circuit units side by side in a demux area of a non-display area of the substrate and electrically connected between data lines and the display driving circuit, test signal supply lines in the non-display area and transmitting test signals for testing the lighting state of light emitting elements of the light emitting element layer, and test pad connection lines respectively electrically connected to test signal pads in the sub-area and extending to the non-display area. The test signal supply lines are electrically connected to the test pad connection lines through test line connection contact holes, respectively. The test line connection contact holes are in a test connection area which is a part of the demux area adjacent to the sub-area.