Optical Beam Drift Detection With Focal and Afocal Paths

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Solution Overview

Problem

Existing light beam drift detection devices require large optical distances to achieve satisfactory sensitivity, resulting in significant space requirements and limitations in compactness and cost-effectiveness.

Innovation Solution

A compact optical device using a beam splitter and afocal module to create a virtual large distance between optical matrix detectors, allowing for high sensitivity in detecting angular and lateral shifts of a light beam, utilizing two optical paths with a focal module for focused light and an afocal module for collimated light to achieve accurate measurements with shorter optical paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If large optical distances are used between optical elements, then measurement precision of angular and lateral position shifts is improved, but device volume and space requirements increase significantly

Engineering Contradiction:
Improveangular position shift resolutionVSAvoiddevice volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent transforms the measurement problem from a one-dimensional spatial distance requirement to a multi-dimensional optical path configuration. By using a beam splitter to create separate focal and afocal measurement paths, the system achieves equivalent measurement precision to large-distance configurations while compacting the physical device volume. The focal module and afocal module operate in different optical dimensions, allowing simultaneous near-field and far-field measurements in a compact arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The measurement function is segmented into two independent optical paths: a focal path for near-field measurements and an afocal path for far-field measurements. Each path uses dedicated detection means (first and second light beam matrix detection means) that can be positioned independently. This segmentation allows the system to achieve the measurement precision of large-distance configurations without requiring the actual physical space, as each segmented path optimizes its own measurement geometry.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If detector distance from light beam is increased to improve angular shift detection, then sensitivity to angular shifts is improved, but device complexity and optical path length increase

Engineering Contradiction:
Improveangular shift detection sensitivityVSAvoidoptical path configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The afocal module acts as an optical intermediary that transforms angular shift measurements into lateral position measurements on the detector plane. Instead of requiring the detector to be positioned at a large distance to measure angular shifts directly, the afocal module mediates this measurement by creating a virtual imaging relationship. This intermediary optical system achieves the same measurement sensitivity with a compact physical arrangement, reducing device complexity while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If compact optical paths are used, then device volume is reduced, but measurement precision and sensitivity decrease

Engineering Contradiction:
Improvedevice compactnessVSAvoidbeam drift detection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent creates a universal measurement system where the same compact optical device can perform both near-field measurements (through the focal module) and far-field measurements (through the afocal module). The beam splitter enables the system to universally handle different measurement modes simultaneously using the same incident light beam. This multi-functionality allows compact device volume while maintaining measurement precision across different measurement scenarios, as each functional module is optimized for its specific measurement type.

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

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 device provides high measurement accuracy and sensitivity for detecting light beam shifts with compactness, enabling the use of smaller, less expensive detectors and efficient alignment of large diameter beams, reducing the need for extensive space and costly large detectors.

Implementation Method 1

a beam splitter for obtaining from said light beam: a first light beam along a first optical path, and a second light beam, along a second optical path

Methodology Applied
Scientific EffectLight beam splitting: Reflection

Implementation Method 2

a focal module positioned at least partially along the first optical path of said first light beam to obtain from said first light beam a focused light beam

Methodology Applied
Scientific EffectOptical focusing: Lens

Implementation Method 3

an afocal module positioned at least partially along the second optical path of said second light beam to obtain from said second light beam a collimated light beam

Methodology Applied
Scientific EffectOptical collimation: Lens

Implementation Method 4

a first light beam matrix detection means positioned in a focusing plane associated with said focal module; a second light beam matrix detection means

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP3774156B1Optical detection of the drift of a light beam
Publication Date: 2022.05.11 LASER ENG APPL
  • EP3774156B1 patent drawingFigure 1a~1b
  • EP3774156B1 patent drawingFigure 2
  • EP3774156B1 patent drawingFigure 3a

AI summary

An optical device (100) for detecting the drift of a light beam of a laser machining system and comprising: - a beam splitter (50) for obtaining: o a first light beam (3) along a first optical path, and o a second light beam (4), along a second optical path; - a focal module (300) positioned at least partially along the first optical path to obtain a focused light beam, said focused light beam is directed towards a first light beam matrix detection means (30) positioned in a focusing plane (12) associated with said focal module (300); - an afocal module (400) positioned at least partially along the second optical path to obtain a collimated light beam (5), said collimated light beam (5) is directed towards a second light beam matrix detection means (40).