Laser Processing Alignment With 6-DOF Stage and Beam Shaping

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Solution Overview

Problem

Current processing apparatuses using laser beams in machine tools face challenges in achieving high precision and efficiency due to limitations in aligning and controlling the workpiece's position and attitude relative to the beam irradiation system, particularly in maintaining accurate six degrees of freedom movement and intensity distribution of the beams.

Innovation Solution

The processing apparatus employs a Stewart platform-type six degrees of freedom parallel link mechanism for precise movement and control of the workpiece, combined with a complex beam irradiation system that includes a mask stage and a condensing optical system with a spatial light modulator to adjust the beam intensity distribution, allowing for precise alignment and processing of the workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a Stewart platform-type six degrees of freedom parallel link mechanism is used for precise movement and control of the workpiece, then manufacturing precision and positioning accuracy are improved, but device complexity increases

Engineering Contradiction:
Improveworkpiece positioning accuracyVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The six degrees of freedom parallel link mechanism is divided into multiple independent linkages and actuation systems, each responsible for specific motion control. This segmentation allows precise control of workpiece position and orientation while maintaining modularity that manages system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The Stewart platform mechanism serves multiple functions simultaneously: it provides six degrees of freedom motion control, maintains workpiece positioning accuracy, and enables complex orientation adjustments. This multi-functionality reduces the need for separate mechanisms, thereby managing overall device complexity while achieving high precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If a complex beam irradiation system with spatial light modulator is used to adjust beam intensity distribution, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvebeam intensity control accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The spatial light modulator dynamically adjusts the beam intensity distribution in real-time, allowing precise control of processing parameters. This dynamic control capability enables high manufacturing precision while the programmable nature of the modulator manages complexity through software control rather than fixed mechanical adjustments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The beam intensity distribution is controlled by changing optical parameters through the spatial light modulator, such as phase and amplitude modulation. This parameter-based control allows precise beam shaping and intensity distribution adjustment without requiring complex mechanical reconfiguration of the optical system.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If precise alignment and control of workpiece position and attitude is implemented, then manufacturing precision is improved, but productivity decreases due to longer setup and adjustment time

Engineering Contradiction:
Improveprocessing accuracyVSAvoidprocessing throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system implements feedback control for workpiece position and attitude, continuously monitoring and adjusting the six degrees of freedom motion to maintain precise alignment. This automated feedback loop eliminates manual adjustment time while maintaining high precision, thereby resolving the contradiction between accuracy and productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary positioning and alignment of the workpiece using the Stewart platform before the actual beam processing begins. This preliminary action establishes precise initial conditions that enable high-precision processing without requiring time-consuming adjustments during production, thus maintaining both accuracy and productivity.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If six degrees of freedom movement control is implemented for the workpiece, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition and attitude control accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical control mechanisms with a combination of the Stewart platform's inherent mechanical advantages and electronic control systems. The parallel link mechanism provides natural mechanical stability and precision, while electronic sensors and actuators manage the six degrees of freedom control, reducing overall system complexity compared to traditional sequential control mechanisms.

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

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 configuration enables high-precision processing with improved throughput and accuracy, allowing for efficient removal processing and other machining operations by precisely controlling the workpiece's position and attitude and optimizing the beam intensity distribution.

Implementation Method 1

a Stewart platform-type six degrees of freedom parallel link mechanism for precise movement and control of the workpiece

Methodology Applied
Scientific EffectParallel link mechanism:

Implementation Method 2

a condensing optical system with a spatial light modulator to adjust the beam intensity distribution

Methodology Applied
Scientific EffectOptical condensing: Focusing

Implementation Method 3

a condensing optical system with a spatial light modulator to adjust the beam intensity distribution

Methodology Applied
Scientific EffectLight modulation:

Implementation Method 4

processing apparatus to process a workpiece by irradiating the workpiece with a beam

Methodology Applied
Scientific EffectLaser irradiation: Laser

Data Source

PatentEP3639967B1Processing apparatus and processing method
Publication Date: 2024.03.27 NIKON CORP
  • EP3639967B1 patent drawingFigure 1
  • EP3639967B1 patent drawingFigure 2
  • EP3639967B1 patent drawingFigure 3

AI summary

A processing apparatus is equipped with: a first stage system that has a table (12) on which a workpiece (W) is placed and moves the workpiece held by the table; a beam irradiation system (500) that includes a condensing optical system (530) to emit beams (LB); and a controller to control the first stage system and the beam irradiation system, and processing is performed to a target portion of the workpiece while the table and the beams from the condensing optical system are relatively moved, and at least one of an intensity distribution of the beams at a first plane (MP) on an exit surface side of the condensing optical system and an intensity distribution of the beams at a second plane whose position in a direction of an optical axis (AX) of the condensing optical system is different from the first plane can be changed.