Surface-Structured Ultrasonic Tool for Laser-Assisted Bonding

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Solution Overview

Problem

Existing ultrasonic tools face challenges in efficiently coupling a laser beam into a longitudinal recess, leading to difficulties in laser-assisted ultrasonic bonding or welding, with issues such as vapor generation, particle release, and contamination due to directed reflection.

Innovation Solution

A surface-structured absorption area on the ultrasonic tool, designed to absorb and diffuse laser beams, reducing reflection and promoting uniform heating, is implemented. This area is structured to enhance absorption capacity and is positioned near the connection contact surface, with microstructures optimized for laser wavelength and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a longitudinal recess is used to guide the laser beam, then the laser beam can be coupled into the tool, but directed reflection occurs causing damage to optical components and contamination

Engineering Contradiction:
Improvelaser beam couplingVSAvoiddirected reflection damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful directed reflection into beneficial diffuse reflection by providing a rounded end surface instead of a longitudinal recess. The rounded surface diffuses the laser beam reflection in multiple directions, preventing damage to optical components while still allowing the laser beam to effectively heat the tool tip for bonding operations

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Instead of using a longitudinal recess that directs the laser beam through the tool, the patent inverts the approach by using a rounded end surface that faces the laser beam source. This inversion changes the interaction from transmission through a cavity to direct incidence on a curved surface, eliminating the directed reflection problem

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If the laser beam strikes the connecting component directly, then bonding can be achieved, but vapor generation and particle release cause contamination

Engineering Contradiction:
Improvebonding efficiencyVSAvoidvapor and particle contamination
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The rounded end surface acts as an intermediary between the laser beam and the connecting component. It absorbs and diffuses the laser energy, generating vapor and particles in a controlled manner that is directed away from the bonding zone, thereby preventing contamination while maintaining bonding efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If a longitudinal recess with absorption coating is used, then laser energy absorption is improved, but the tool structure becomes more complex and difficult to manufacture

Engineering Contradiction:
Improvelaser energy absorptionVSAvoidtool structure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent extracts the complex longitudinal recess structure and replaces it with a simple rounded end surface. This simplification removes the need for internal coatings and complex machining while maintaining effective laser energy absorption through the curved geometry that promotes multiple internal reflections and energy concentration at the tip

Inventive Principle:
Principle #2Taking out (Extraction)

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 structured absorption surface effectively absorbs a high percentage of laser energy, preventing damage to surrounding components and contamination, while ensuring rapid and uniform heating of the tool, thus improving the suitability for laser-assisted bonding and welding.

Implementation Method 1

the absorption surface ensures, firstly, that a laser beam directed at it is essentially absorbed and otherwise diffusely reflected

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the surface-structured absorption surface can be designed as a beam trap for an incident laser beam, such that the laser beam striking the absorption surface is reflected multiple times and is always partially absorbed

Methodology Applied
Scientific EffectMultiple internal reflection: Reflection

Implementation Method 3

The ultrasonic tool is excited to vibrations, such as torsional, bending, or longitudinal vibrations, via the transducer, which typically uses piezoelectric transducers as vibration exciters

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 4

a high percentage of the energy supplied via the laser beam heating the ultrasonic tool

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 5

the absorption surface ensures, firstly, that a laser beam directed at it is essentially absorbed

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP4028178B1Ultrasonic tool and ultrasonic connection device herein
Publication Date: 2025.11.05 HESSE
  • EP4028178B1 patent drawingFigure 1
  • EP4028178B1 patent drawingFigure 2~3
  • EP4028178B1 patent drawingFigure 4

AI summary

The invention relates to an ultrasonic tool (1) comprising a first end face (2) and a second end face (3, 3') which is opposite the first end face (2), as well as a tool cover surface (4) connecting the first end face (2) and the second end face (3, 3'), wherein the ultrasonic tool (4) is elongated in a longitudinal direction (5) of the tool, wherein at least the first end face (2, 3') is formed as a connecting contact surface (2, 3') which is arranged for pressing the ultrasonic tool (1) against a connecting component, wherein the ultrasonic tool (1) has an end region (6) comprising the connecting contact surface (2, 3') and which extends from the connecting contact surface (2, 3') in the longitudinal direction (5) of the tool over 15 mm, but at most one third of a length (L) of the ultrasonic tool (1) in the direction of the opposite end face (2, 3, 3'), and wherein in the end region (6) a first partial surface of the tool cover surface (4) is formed as a surface-structured absorption surface (7). The invention also relates to an ultrasonic connection device for ultrasonic welding and/or ultrasonic bonding with the ultrasonic tool (1).