LED Wiring Formation Using Laser-Patterned Metal Paste

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Solution Overview

Problem

Existing light-emitting device manufacturing methods are inefficient and costly, requiring sophisticated equipment for forming metal layers and prone to short circuits due to the need for thick metal layers, which can break easily.

Innovation Solution

A light-emitting device is fabricated using a metal paste layer comprising a mixture of resin and metal powder, where the metal paste layer is continuously covered over paired electrodes and a covering member, and then patterned using laser ablation to form wirings, reducing the risk of short circuits and improving working efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick metal layer is used to prevent short circuits, then reliability improves, but the device size increases and the metal layer becomes more prone to breakage

Engineering Contradiction:
Improveshort circuit preventionVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent uses a composite paste material containing metal particles, glass particles, and organic vehicle. The glass particles provide structural support and prevent short circuits without requiring thick metal layers, while the organic vehicle enables precise patterning through laser ablation. This composite approach resolves the contradiction by achieving reliability through material composition rather than layer thickness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces traditional mechanical thick metal layer construction with a chemical/composite-based solution. The paste material's glass particles provide the necessary electrical isolation and structural integrity, substituting the mechanical approach of simply increasing metal layer thickness with a multi-component material system that achieves the same goal with thinner overall structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If sophisticated equipment is used for forming metal layers, then manufacturing precision improves, but device complexity and cost increase

Engineering Contradiction:
Improvewiring formation precisionVSAvoidequipment sophistication
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces an organic vehicle as an intermediary material that enables precise wiring formation through laser ablation. Instead of using complex equipment to directly form metal layers, the organic vehicle serves as a sacrificial intermediary that can be selectively removed, leaving precisely formed metal patterns. This simplifies the equipment requirements while maintaining high manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical and chemical parameters of the metal formation process by using a paste material with organic vehicle that responds to laser irradiation. The organic vehicle's properties (volatility, laser absorption) are optimized to enable precise removal, transforming the manufacturing process from requiring complex mechanical/electrical equipment to using controllable laser parameters for precise wiring formation.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If laser ablation is used to pattern metal paste layer, then productivity improves, but the process requires precise control

Engineering Contradiction:
Improvewiring formation efficiencyVSAvoidlaser ablation control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the organic vehicle's physical parameters (volatility, laser absorption coefficient, viscosity) to enable efficient laser ablation. By carefully controlling these parameters, the material responds predictably to laser irradiation, allowing high-speed patterning while maintaining precision. The parameter optimization resolves the contradiction by making the material itself easier to control during the laser process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite paste material's composition is optimized so that the organic vehicle component provides ideal laser ablation characteristics. The combination of metal particles, glass particles, and organic vehicle creates a material that can be rapidly and precisely patterned by laser, achieving high productivity while the consistent material properties ensure precise control during the ablation process.

Inventive Principle:
Principle #40Composite materials

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 method allows for the easy and precise formation of wirings, enhances working efficiency, and reduces the likelihood of wiring breakage, enabling the creation of a smaller and more reliable light-emitting device.

Implementation Method 1

paired wirings being formed by irradiation of a metal paste layer continuously covering the paired electrodes and the first covering member with laser light to remove the metal paste layer between the paired electrodes

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3869573B1Light emitting device
Publication Date: 2024.06.26 NICHIA CORP
  • EP3869573B1 patent drawingFigure 1A~1B
  • EP3869573B1 patent drawingFigure 1C~2A
  • EP3869573B1 patent drawingFigure 2B~2C

AI summary

A method for manufacturing a light-emitting device includes preparing an intermediate product; the product includes a light-emitting element provided with pairedelectrodes at a first surface and a first covering member covering the light-emitting element such that portions of surfaces of the paired electrodes are exposed. A a metal paste layer is formed, continuously covering the exposed portion of the paired electrodes and the first covering member. Paired wirings are formed, for preventing the paired electrodes from being short-circuited. The metal paste layer on the paired electrodes and the metal paste layer on the first covering member are irradiated with laser light to remove the metal paste layer between the paired electrodes and a portion of the metal paste layer on the first covering member.