Laser Beam Shaping for Uniform Target Heating in Evaporation

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Solution Overview

Problem

High-power laser systems used in evaporation systems fail to maintain uniform temperature distribution across the target surface due to radiation losses, leading to severe temperature deviations as temperatures increase, especially towards the outer rim.

Innovation Solution

A method and system that adaptively shape the laser beam's intensity profile based on temperature information, providing higher intensity at the outer rim and lower intensity at the center to compensate for radiation losses, ensuring a more uniform temperature distribution by using a beam shaping system comprising axicons and a clipping aperture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a flat intensity profile laser beam is used to heat the target surface, then uniform energy deposition is achieved, but temperature uniformity deteriorates at higher temperatures due to radiation losses

Engineering Contradiction:

Improveenergy deposition uniformityVSAvoidtemperature uniformity

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent applies local quality by modifying the laser beam intensity profile to have different intensity values at different locations (higher at edges, lower at center) to compensate for location-specific radiation losses. This creates a non-uniform intensity distribution that counteracts the non-uniform temperature distribution caused by radiation losses at the target surface edges.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional approach by using a non-uniform intensity profile (with maximum at edges) instead of a uniform profile. This inversion compensates for the fact that radiation losses are highest at the edges, thereby achieving uniform temperature distribution across the target surface.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If higher laser power is used to increase heating efficiency, then productivity improves, but temperature deviations become more severe

Engineering Contradiction:

Improveheating efficiencyVSAvoidtemperature uniformity

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent uses local quality by applying different intensity levels to different regions of the target surface. The enhanced edge intensity compensates for radiation losses that become more severe at higher temperatures, allowing the system to operate at higher power levels while maintaining temperature uniformity.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a uniform intensity profile is maintained, then beam shaping simplicity is preserved, but temperature control precision deteriorates

Engineering Contradiction:

Improvebeam shaping complexityVSAvoidtemperature control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the intensity distribution parameter of the laser beam from uniform to non-uniform (with maximum at edges). This parameter change is achieved through optical elements like axicons that transform the beam profile, enabling precise temperature control by compensating for radiation losses without excessive system complexity.

Inventive Principle:

Principle #35Parameter changes

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 adaptive intensity profile achieves a spatially uniform temperature across the target surface, reducing temperature gradients and maintaining consistent heating even at higher temperatures.

Implementation Method 1

surfaces of bodies containing solid and/or liquid material can be heated in particular in a vacuum environment by means of laser radiation

Methodology Applied

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

Implementation Method 2

shaping the intensity profile of the laser beam based on the determination carried out in step b)

Methodology Applied

Scientific EffectOptical beam shaping:

Implementation Method 3

at the higher powers and therefore higher temperatures of the heated material, flat intensity profiles impinging with a constant power density onto the irradiated surface no longer produce a uniform temperature across the irradiated surface due to radiation losses

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS20240091878A1Method of running a laser system, laser system and evaporation system

Publication Date: 2024.03.21 MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN EV

AI summary

The present invention is related to a method for running a laser system (10) for providing a laser beam (22) for heating a surface (68) of a target (66) located in a reaction chamber (62) of an evaporation system (60), the laser system (10) comprising a laser light source (20) for providing an at least essentially parallel laser beam (22) with an at least essentially centrally peaked intensity profile (24). In addition, the present invention is related to a laser system (10) for heating a surface (68) of a target (66) located in a reaction chamber (62) of an evaporation system (60), the reaction chamber (62) comprising a chamber window (64), and the laser system (10) comprising a laser light source (20) for providing an at least essentially parallel laser beam (22) with an at least essentially centrally peaked intensity profile (24). Further, the present invention is related to an evaporation system (60) the evaporation system (60) comprising a target (66) located in a reaction chamber (62) and at least one laser system (10) for heating a surface (68) of the target (66).