Display Device Metal-Layer Layout for Uniform Power Delivery
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Solution Overview
Problem
Existing display devices face issues such as non-uniformity of anode power supply voltage (IR drop), capacitive coupling leading to inaccurate potential retention, and breakage of thin metal lines in flexible displays due to bending, particularly in regions with varying pixel densities.
Innovation Solution
A display device configuration with distinct metal layer patterns in high and low-density regions, including a third metal layer with a main region and island region, which forms capacitors to stabilize power supply and reduce IR drop, and a via region for interconnection, enhancing capacitive element performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform metal layer pattern is used across the entire display region, then the manufacturing process is simple, but IR drop causes non-uniform power supply voltage in regions with varying pixel densities
Solution Approach 1:
The patent applies local quality by configuring the third metal layer with different occupancy rates in different display regions. Specifically, the third metal layer has higher occupancy in the first display region (higher pixel density) and lower occupancy in the second display region (lower pixel density). This localized adjustment compensates for IR drop effects in high-density regions while maintaining adequate power supply in low-density regions, thereby achieving uniform power supply voltage across the entire display without complicating the overall manufacturing process.
2Reliability
If the third metal layer has high occupancy to form stable capacitors, then power supply stability improves, but capacitive coupling increases causing inaccurate potential retention
Solution Approach 1:
The patent resolves this contradiction by applying local quality through region-specific third metal layer configurations. In the first display region where higher pixel density demands greater power supply stability, the third metal layer maintains higher occupancy to form robust capacitors. In the second display region where lower pixel density reduces power demands, the third metal layer reduces occupancy to minimize capacitive coupling interference. This localized adjustment allows the system to optimize both power supply stability and potential retention accuracy according to regional requirements.
3Quantity of substance
If thin metal lines are used to reduce material consumption, then manufacturing cost decreases, but the lines become prone to breakage during bending in flexible displays
Solution Approach 1:
The patent applies the principle of flexible shells and thin films by introducing a third metal layer configured as a mesh or island structure with controlled occupancy. This third metal layer acts as a reinforcement network that distributes mechanical stress across the flexible display structure during bending. The strategic placement of metal regions provides structural support to prevent breakage of thinner metal interconnect lines, while the optimized occupancy pattern minimizes overall metal material consumption by placing reinforcement only where structurally necessary.
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
The solution reduces IR drop and capacitive coupling, ensuring stable power supply and accurate potential retention, while minimizing breakage risks in flexible displays with varying pixel densities.
Implementation Method 1
a main region configured to be supplied with a power supply potential and form a capacitor included in a first capacitive element with the second metal layer, the first capacitive element being configured to store a voltage to control the driving transistor
Data Source
AI summary
A second display region has a lower pixel density than a first display region. A third metal layer is located upper than a first metal layer and a second metal layer. The occupancy of the third metal layer in the second display region is lower than the occupancy in the first display region. In a pixel unit, the first metal layer includes a first electrode region to control an amount of electric current in a driving transistor, the second metal layer includes a second electrode region and a third electrode region to supply current to the driving transistor, and the third metal layer includes a main region to form a capacitor included in a capacitive element to store a control voltage for the driving transistor, and an island region surrounded by the main region with a gap and interconnected with a lower electrode region by a via region.