Top-Hat Laser Separation of Coated Substrates Without Debris

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Solution Overview

Problem

Existing laser cutting processes for coated substrates often result in unacceptable debris, defects, and subsurface damage due to the absorption of laser beams by coatings, which alters the beam propagation and causes separation issues.

Innovation Solution

A method involving the use of an infrared laser beam directed onto a coated substrate with a coating layer on a transparent workpiece, where the laser beam projects a beam spot that traces an oscillating pathway on the dummy region of the substrate, applying thermal energy to defects and inducing separation along a contour line without damaging the primary region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a laser beam is directed onto a coated substrate for cutting, then separation of the substrate is achieved, but the coating absorbs the laser beam causing unacceptable debris, defects, and subsurface damage

Engineering Contradiction:
Improvesubstrate separation efficiencyVSAvoiddebris and defects
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different qualities to different regions of the substrate by introducing a dummy region with modified optical properties (different thickness or material composition) compared to the functional region. This allows the laser to effectively cut through the coating in the dummy region while preserving the functional region from laser-induced damage, thereby resolving the contradiction between cutting efficiency and harm reduction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary dummy region that acts as a mediator between the laser beam and the functional substrate. This dummy region absorbs the laser energy and facilitates substrate separation through controlled fracture propagation, preventing direct laser interaction with the functional region and thus eliminating debris and defect generation in the functional area.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If the laser beam propagates through the coating layer, then cutting depth is achieved, but the coating absorption alters beam propagation causing separation issues

Engineering Contradiction:
Improvecutting depthVSAvoidseparation accuracy
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent modifies the local optical properties of the substrate by creating a dummy region with different thickness or material characteristics. This local quality change enables the laser beam to propagate deeper into the dummy region while maintaining precise control over fracture propagation, thereby achieving both sufficient cutting depth and high separation accuracy without beam distortion.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If thermal energy is applied to induce separation along the contour line, then precise separation is achieved, but the primary region may be damaged by excessive thermal energy

Engineering Contradiction:
Improveseparation precisionVSAvoidthermal damage to primary region
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent creates a dummy region with modified optical or thermal properties that allows concentrated thermal energy application for precise separation while protecting the functional region. The dummy region can be designed with different thermal conductivity, heat capacity, or optical absorption characteristics to localize thermal effects and prevent heat diffusion into the primary functional area, thus achieving precise separation without thermal damage.

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 method effectively separates coated substrates with minimal debris and damage to the primary region, achieving precise control over thermal energy application to induce separation along the desired contour line.

Implementation Method 1

the infrared laser beam applies thermal energy to the plurality of defects disposed in the coated substrate and inducing separation of the coated substrate along the contour line

Methodology Applied
Scientific EffectThermal energy application: Heating

Implementation Method 2

the infrared laser beam applies thermal energy to the plurality of defects disposed in the coated substrate and inducing separation of the coated substrate along the contour line

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

the infrared beam spot applies thermal energy to the dummy region of the coated substrate without melting or ablating the coating layer of the primary region of the coated substrate

Methodology Applied
Scientific EffectThermal energy application: Heating

Implementation Method 4

directing an infrared laser beam onto a first surface of the coated substrate

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP4164835B1Methods for laser processing coated substrates using a top-hat energy distribution
Publication Date: 2025.01.29 CORNING INC
  • EP4164835B1 patent drawingFigure 1A
  • EP4164835B1 patent drawingFigure 1B
  • EP4164835B1 patent drawingFigure 2

AI summary

A method of separating a coated substrate includes directing an infrared laser beam onto a first surface of the coated substrate. The coated substrate includes a coating layer disposed on a transparent workpiece, a plurality of defects is disposed within the coated substrate along a contour line that divides a primary region from a dummy region of the coated substrate from a dummy region of the coated substrate. The method also includes translating at least one of the coated substrate and the infrared laser beam relative to each other such that an infrared beam spot traces an oscillating pathway that follows an offset line in a translation direction and oscillates between an inner and outer track line, the oscillating pathway is disposed on the dummy region of the coated substrate, and the infrared laser beam applies thermal energy to the plurality of defects to induce separation of the coated substrate.