OLED Mesh Power Supply for Voltage Drop Reduction

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Solution Overview

Problem

Organic light-emitting diode displays face issues with undesired voltage drops due to resistive losses in conductive paths, leading to interference with display performance and challenges in configuring signal distribution paths for satisfactory operation.

Innovation Solution

A mesh-shaped power supply distribution path is used, comprising horizontally extending zigzag metal lines that do not overlap the anodes of light-emitting diodes and vertically extending straight metal lines that overlap the anodes, minimizing ohmic losses and ensuring uniform brightness across the display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional conductive paths are used to distribute power supply signals, then the display can be manufactured with simpler structures, but undesired voltage drops occur due to resistive losses interfering with display performance

Engineering Contradiction:
Improvedisplay performanceVSAvoidvoltage drops
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The power supply distribution path is segmented into multiple conductive paths arranged in a mesh configuration, dividing the single long path into numerous shorter segments. This segmentation reduces the total resistance in each path, thereby minimizing voltage drops and improving power distribution reliability across the display.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power distribution network transitions from a conventional one-dimensional linear path to a two-dimensional mesh structure. This dimensional change creates multiple redundant pathways for current flow, reducing resistive losses and improving voltage uniformity across the display while maintaining manufacturing feasibility.

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

2Reliability

If care is not taken in configuring signal distribution paths, then the manufacturing process remains simple, but satisfactory display performance cannot be achieved due to voltage drops

Engineering Contradiction:
Improvedisplay operationVSAvoidconductive path configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conductive path is segmented into multiple interconnected segments forming a mesh pattern. This segmentation ensures that no single path carries excessive current, reducing voltage drops and improving operational reliability while the systematic mesh pattern keeps manufacturing complexity manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive path geometry is changed from linear to mesh configuration, altering the electrical parameters such as total resistance and current distribution. This parameter change improves voltage uniformity across the display while the mesh pattern remains compatible with standard manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If horizontally extending conductive lines overlap light-emitting diode anodes, then manufacturing is simpler, but color shifts occur as a function of viewing angle

Engineering Contradiction:
Improvedisplay colorVSAvoidconductive line configuration
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The mesh pattern uses asymmetric positioning where horizontal conductive lines are deliberately placed to avoid overlapping with anodes, while vertical lines may overlap. This asymmetric configuration prevents color shifts from viewing angle changes while maintaining ease of manufacture through systematic line placement rules.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Different regions of the mesh pattern have different properties: horizontal lines are positioned to avoid anodes (no overlap), while vertical lines are allowed to overlap anodes. This local differentiation in overlap quality prevents color shifts while keeping the overall structure manufacturable.

Inventive Principle:
Principle #3Local quality

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 reduces IR losses and minimizes color shifts as a function of viewing angle by maintaining consistent anode overlap with the power supply distribution path, enhancing display brightness uniformity and color stability.

Implementation Method 1

Signals in organic light-emitting diode displays such as power supply signals may be subject to undesired voltage drops due to resistive losses in the conductive paths

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

undesired voltage drops due to resistive losses

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 3

an organic light-emitting diode display based on organic-light-emitting diode pixels

Methodology Applied
Scientific EffectOrganic Light-emitting Diode: Organic Light-emitting Diode

Implementation Method 4

Each light-emitting diode may have an anode and a cathode

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3488437B1Display with power supply mesh
Publication Date: 2020.11.11 APPLE INC
  • EP3488437B1 patent drawingFigure 1
  • EP3488437B1 patent drawingFigure 2
  • EP3488437B1 patent drawingFigure 3

AI summary

An organic light-emitting diode display may have an array of pixels. The pixels may each have an organic light-emitting diode with a respective anode and may be formed from thin- film transistor circuitry formed on a substrate. A mesh-shaped path may be used to distribute a power supply voltage to the thin-film circuitry. The mesh-shaped path may have intersecting horizontally extending lines and vertically extending lines. The horizontally extending lines may be zigzag metal lines that do not overlap the anodes. The vertically extending lines may be straight vertical metal lines that overlap the anodes. The pixels may include pixels of different colors. Angularly dependent shifts in display color may be minimized by ensuring that the anodes of the differently colored pixels overlap the vertically extending lines by similar amounts.