Free Form OLED Link Lines for Voltage Uniformity

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Solution Overview

Problem

Free form display devices face challenges in maintaining luminance uniformity and preventing short circuits between signal lines due to varying lengths and arrangements of power supply and scan lines, which degrade display quality and reliability.

Innovation Solution

The implementation of a display device with a substrate featuring a free form active area and a bezel area that includes power supply routing lines, scan routing lines, and link lines to connect these lines, ensuring uniform voltage distribution and preventing short circuits by using multiple link lines and auxiliary link lines to compensate for length variations and maintain equipotentiality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional square display devices are used, then the arrangement of components is simple and standardized, but free form display devices require novel line arrangement structures that increase device complexity

Engineering Contradiction:
Improvedisplay shape flexibilityVSAvoidline arrangement structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The display device is divided into a display area and a bezel area, with different line arrangement strategies applied to each region. Power supply lines, scan lines, and data lines are segmented and routed through specific paths in the bezel area to connect to the display area, allowing flexible overall shape while maintaining organized internal connections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the bezel area as an additional dimensional space for routing power supply lines and other signal lines. By extending lines into the bezel region and using multi-layer structures, the patent achieves flexible display shapes without compromising the organization and manageability of internal connections.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If power supply lines are extended to cover larger areas in free form displays, then more pixels can be powered, but voltage drop increases causing non-uniform luminance

Engineering Contradiction:
Improvepower supply coverage areaVSAvoidluminance uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The power supply system is segmented into multiple independent power supply lines that are distributed across the display area. Each power supply line serves a specific region, preventing excessive voltage drop by limiting the length of individual power transmission paths while maintaining broad coverage through multiple parallel lines.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs power supply lines to achieve equipotential distribution across the display area by carefully controlling their routing and connection points. Multiple power supply lines are arranged to provide redundant paths, ensuring that voltage levels remain uniform across different regions of the display despite variations in line length and load distribution.

Inventive Principle:
Principle #12Equipotentiality

3Area of stationary object

If signal lines are arranged closely to maximize display area, then device size is minimized, but short circuits between lines carrying different signals become more likely

Engineering Contradiction:
Improvedisplay areaVSAvoidshort circuit prevention
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The bezel area serves as an intermediary zone that separates and organizes different signal lines before they enter the display area. Power supply lines, scan lines, and data lines are routed through this intermediate region, allowing for proper spacing and insulation to be maintained while still achieving compact overall device dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes multi-layer structures to separate signal lines that would otherwise need to be spaced far apart on a single layer. By routing different signal types on different layers and using the bezel area for inter-layer connections, the patent achieves close packing while maintaining electrical isolation through vertical separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3174042B1Organic light emitting diode display
Publication Date: 2019.10.23 LG DISPLAY CO LTD
  • EP3174042B1 patent drawingFigure 1
  • EP3174042B1 patent drawingFigure 2
  • EP3174042B1 patent drawingFigure 3

AI summary

A display device including a substrate comprising a free form active area having pixels defined by scan lines, data lines, and power supply lines, and a bezel area located outside the active area and having power supply routing lines to which a power supply voltage is applied and scan routing lines to which scan pulses are applied; and link lines that are disposed in the bezel area, and that connect the power supply routing lines to the power supply lines and transmit the power supply voltage from the power supply routing lines to the power supply lines, the link lines comprising: a plurality of first link lines; and one or more second link lines that interconnect the first link lines, each of the first link lines comprising one end connected to the power supply routing lines and the other end connected to the power supply lines.