Display Pad and Electrode Layout for Current Density Dispersion
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Solution Overview
Problem
Heat generation and reliability issues in display devices due to concentrated electric current in the region where the power voltage line and cathode electrode are connected, leading to potential deterioration.
Innovation Solution
A display device structure is designed with varying widths of power lines and a metal pattern on the power voltage pad, increasing the area around the heat generation region, and incorporating a planarization layer with trenches to expose electrodes, enhancing reliability by reducing current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power voltage is applied to the cathode electrode to operate the light-emitting element, then the light-emitting element operates, but heat is concentrated in the region where the power voltage line and cathode electrode are connected
Solution Approach 1:
The power voltage pad is divided into multiple sub-pads (first sub-pad, second sub-pad, third sub-pad) with different shapes and areas. This segmentation allows the electric current to be distributed across multiple regions rather than concentrated in a single pad, thereby reducing heat generation at the connection region between the power voltage line and cathode electrode.
Solution Approach 2:
Different sub-pads are designed with different areas and shapes according to local requirements. The first sub-pad has a specific area configuration, the second sub-pad has a different area configuration, and the third sub-pad has yet another configuration. This local quality differentiation optimizes current distribution in different regions of the pad structure.
2Temperature
If the area of the power voltage pad is increased to reduce current density, then heat generation is reduced, but the device complexity increases due to multiple sub-pads and connection lines
Solution Approach 1:
The power voltage pad is segmented into multiple sub-pads connected through connection lines. This segmentation increases the total effective area for current distribution while managing heat generation. The first sub-pad, second sub-pad, and third sub-pad are connected via first connection lines and second connection lines to distribute current across a larger area.
Solution Approach 2:
The pad structure extends into multiple dimensions with sub-pads arranged in different spatial configurations. The first sub-pad, second sub-pad, and third sub-pad are positioned at different locations and connected through multiple connection lines, utilizing two-dimensional or three-dimensional space to increase effective area without proportionally increasing planar complexity.
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
Minimizes heat-related deterioration and improves the reliability of the display device by dispersing current density and optimizing the power voltage pad structure.
Implementation Method 1
When a power voltage is applied to the cathode electrode to operate the light-emitting element, heat may be concentrated in a region in which a power voltage line and the cathode electrode are connected
Data Source
AI summary
A display device may include a substrate including a display area comprising subpixels, and a non-display area; a pad part at one side of the non-display area and including data pad electrodes and power voltage pad electrodes; a first line part in the display area and including data lines and power lines; a second line part including, in the non-display area, first connection lines connecting the data pad electrodes and the data lines, and second connection lines connecting the power voltage pad electrodes and the power lines; a third electrode that traverses the second line part and in parallel with one side of the substrate; a planarization layer having a first trench that exposes the third electrode; a second electrode connected to the third electrode through the first trench; and fourth electrodes connecting the third electrode and the power voltage pad electrodes.