Three-Laser Silicon Crystallization for Faster High-Crystallinity Displays

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Solution Overview

Problem

The luminous efficiency of display devices varies with the degree of crystallization of polycrystalline silicon, and existing methods do not effectively enhance the crystallinity of amorphous silicon to prevent defects in light emission.

Innovation Solution

A laser crystallization method using an integrated solid-state laser system with multiple lasers of varying energy intensities is employed to increase the melting and solidification times of amorphous silicon, thereby improving the crystallization process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single laser is used for crystallization, then the processing time is short, but the crystallinity of polycrystalline silicon is insufficient

Engineering Contradiction:
Improveprocessing speedVSAvoidcrystallinity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The crystallization process is divided into multiple stages using three separate lasers with different wavelengths. The first laser (1064nm) performs initial heating, the second laser (532nm) performs intermediate heating, and the third laser (355nm) performs final crystallization. This segmentation allows each laser to contribute to different aspects of the crystallization process, achieving both high processing speed and high crystallinity.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple lasers are used to increase crystallinity, then the crystallization quality improves, but the processing time increases

Engineering Contradiction:
ImprovecrystallinityVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The three lasers are operated in a periodic sequence rather than simultaneously. The first laser irradiates, then the second laser irradiates, then the third laser irradiates. This periodic action allows each laser to perform its function efficiently without wasting time, maintaining high processing speed while achieving the crystallinity improvements that would require multiple lasers.

Inventive Principle:
Principle #19Periodic action

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 method enhances the crystallinity of amorphous silicon to polycrystalline silicon, reducing light emission defects and improving the luminous efficiency of display devices.

Implementation Method 1

a first solid state laser L1, a second solid state laser L2 and a third solid state laser L3 are generated and integrated into an integrated solid state laser LS

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

increase the melting and solidification times of amorphous silicon

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

increase the melting and solidification times of amorphous silicon

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 4

Amorphous silicon may be crystallized into polycrystalline silicon by a laser

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP4176999B1Laser crystallization device, laser crystallization method and method of manufacturing display device, with use of three solid state lasers
Publication Date: 2025.11.26 SAMSUNG DISPLAY CO LTD
  • EP4176999B1 patent drawingFigure 1
  • EP4176999B1 patent drawingFigure 2
  • EP4176999B1 patent drawingFigure 3~4

AI summary

The present application relates to a laser crystallization device including a first solid-state laser generator (LE1) which generates a first solid-state laser (L1) having a first energy intensity, a second solid-state laser generator (LE2) which generates a second solid-state laser (L2) having a second energy intensity lower than the first energy intensity, and a third solid-state laser generator (LE3) which generates a third solid-state laser (L3) having a third energy intensity lower than the first energy intensity.