Cathode Connection Parts for OLED Luminance Uniformity
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Solution Overview
Problem
Organic light emitting display devices face non-uniform luminance issues due to voltage drop caused by line resistance, particularly in high-resolution displays where power supply pad placement is constrained, leading to difficulties in distributing high-level and low-level power effectively.
Innovation Solution
The design incorporates a display panel with a cathode layer and cathode connection parts that supply a first supply voltage, where each cathode connection part has a contact area between 10% and 90% of its overlapping area with the cathode layer, and includes electrode layers and intermediate conductive layers to facilitate efficient power distribution, with separate flexible circuit films for high-level and low-level power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power supply pads are placed at constrained locations in high-resolution displays, then device integration is improved, but voltage drop due to line resistance increases causing non-uniform luminance
Solution Approach 1:
The power supply system is segmented into multiple cathode connection parts distributed across the display panel, each independently supplying power to specific regions. This segmentation reduces the current load on individual power lines, minimizing voltage drop and improving luminance uniformity while maintaining constrained pad placement
Solution Approach 2:
Different regions of the display panel are provided with dedicated cathode connection parts and intermediate conductive layers, creating locally optimized power distribution paths. This ensures that each region receives adequate power regardless of its distance from the main power supply pads, resolving the luminance uniformity issue
2Loss of energy
If cathode connection parts have large contact area with cathode layer, then power distribution efficiency is improved, but risk of overheating and burning increases
Solution Approach 1:
The contact area between cathode connection parts and cathode layer is precisely controlled within the range of 10%-90% of the overlapping area. This parameter optimization balances power distribution efficiency with heat dissipation, ensuring adequate electrical contact while preventing excessive current density that would cause overheating
Solution Approach 2:
Intermediate conductive layers are introduced as mediators between the cathode connection parts and the cathode layer. These intermediate layers distribute the current more evenly across the contact interface, reducing localized current density and preventing burning while maintaining efficient power transfer
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
This configuration minimizes non-uniform luminance by ensuring consistent power delivery to the cathode electrode layer, preventing overheating and burning, and allows for efficient supply of high-level and low-level power without overlapping power lines, thereby maintaining a stable power level across the display panel.
Implementation Method 1
cathode connection parts coupled to the cathode layer to supply the first supply voltage to the cathode layer from the plurality of supply voltage connection pads
Implementation Method 2
minimizes non-uniform luminance by ensuring consistent power delivery to the cathode electrode layer
Data Source
AI summary
Disclosed is an organic light emitting display device. The organic light emitting display device includes a plurality of pixels that include a pixel circuit connected to a gate line, a data line, and a high-level power line, and an emission cell formed between an anode electrode connected to the pixel circuit and a cathode electrode layer receiving low-level power. The organic light emitting display device includes a display panel including a plurality of first pad parts, second pad parts, and cathode connection parts, a plurality of first flexible circuit films respectively connected to the first pad parts to supply the low-level power to a low-level power pad of each of the first pad parts, and a plurality of second flexible circuit films respectively connected to the second pad parts to supply the high-level power to a high-level power pad of each of the second pad parts.