Sub-Pixel Capacitor Shorting for Defective Display Pixel Darkening

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing display devices face challenges in efficiently darkening defective sub-pixels and minimizing damage to surrounding areas during repair processes, particularly due to issues with static electricity and the complexity of connecting light emitting diodes to normal pixel circuits.

Innovation Solution

A display device design that includes a first substrate with sub-pixels, transistors, capacitors, and reflection plates, where the capacitor electrodes connect to each other in defective sub-pixels to facilitate darkening, and a reflection plate connects light emitting diodes to normal pixel circuits using a low-power laser, reducing peripheral damage and static electricity-related defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a high-power laser is used for welding to ensure strong bonding, then the welding strength is improved, but the damage to the periphery of the welding area increases

Engineering Contradiction:
Improvewelding strengthVSAvoidperipheral damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using a low-power laser that concentrates energy precisely on the welding target area. The welding electrode is designed with specific geometric features (protrusion or hole structure) that localize the welding action to a small region, preventing heat diffusion to surrounding areas. This allows strong welding at the contact point while minimizing peripheral damage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The welding electrode serves as an intermediary between the laser energy source and the welding target. It mediates the energy transfer by concentrating the laser energy at its tip or contact point, achieving effective welding with low overall power input. The electrode structure (protrusion or hole) acts as the intermediary that enables precise energy localization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple welding processes are used to darken defective sub pixels, then the darkening effect is achieved, but the manufacturing complexity increases

Engineering Contradiction:
Improvedarkening effectVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the darkening function into a single welding process step. By designing the welding electrode with specific geometric features (protrusion or hole) and positioning it to contact multiple capacitor electrodes simultaneously, the welding operation achieves both electrical connection and darkening of the defective sub pixel in one action, eliminating the need for separate darkening processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The welding electrode is designed with multi-functionality, serving both as the welding tool for electrical connection and as the darkening mechanism for defective pixels. The same welding structure that provides electrical contact also creates the darkening effect through its geometric design, allowing one component to perform multiple functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If reflection plates are connected using conventional welding, then the electrical connection is established, but defects from static electricity occur

Engineering Contradiction:
Improveelectrical connectionVSAvoidstatic electricity defects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The welding electrode acts as an intermediary that enables static-free connection of reflection plates. By using the electrode's protrusion or hole structure to create controlled contact points, the welding process establishes electrical connection without generating static electricity defects that would occur with conventional welding methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables efficient darkening of defective sub-pixels with minimal damage through a simplified repair process, allowing for effective reconnection of light emitting diodes to normal pixel circuits, thereby improving display quality and reducing defects.

Implementation Method 1

allowing for easy darkening and connection to normal pixel circuits using a low-power laser welding process

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP4425550A1Display device
Publication Date: 2024.09.04 LG DISPLAY CO LTD
  • EP4425550A1 patent drawingFigure 1
  • EP4425550A1 patent drawingFigure 2A
  • EP4425550A1 patent drawingFigure 2B

AI summary

According to an aspect of the present disclosure, a display device includes a first substrate in which a plurality of sub pixels including at least one defective sub pixel and a plurality of normal sub pixels is defined; a light emitting diode which is disposed in each of the plurality of sub pixels; a driving transistor having a source electrode connected to a first electrode of the light emitting diode; and a capacitor which includes a plurality of capacitor electrodes connected to a gate electrode and the source electrode of the driving transistor. The plurality of capacitor electrodes is in contact with each other in the defective sub pixel. Accordingly, in the defective sub pixel, the capacitor electrodes are connected to each other to connect the gate electrode and the source electrode of the driving transistor and the defective sub pixel may be easily darkened.