Laser Receiver Beam Classification via Directional Analysis

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Solution Overview

Problem

Existing methods for comparing a received beam with a rotating laser beam struggle to accurately distinguish between the laser beam and reflections, leading to incorrect measurements due to the limitations in existing technologies.

Innovation Solution

The method involves determining the timing and direction of the received beam's movement relative to the laser receiver and comparing it with the direction of rotation of the rotating laser beam, using a detection field with multiple measurement areas to classify the beam as either a rotating laser beam or an extraneous beam based on matching or differing timing and direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If modulation signal is used to classify received beam, then laser beam identification is improved, but reflection detection capability deteriorates

Engineering Contradiction:
Improvelaser beam identification accuracyVSAvoidreflection detection capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection field is divided into multiple photodetector arrays arranged in a specific geometric pattern, with each array independently evaluating the received beam. This segmentation allows the system to compare spatial distribution patterns to distinguish direct laser beams from reflections, resolving the contradiction by adding spatial dimension analysis alongside temporal modulation detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary classification mechanism that first evaluates the spatial distribution of detected light across multiple photodetector arrays before applying modulation signal analysis. This intermediary step identifies potential reflections by detecting abnormal spatial patterns, allowing the system to then apply modulation analysis selectively or with adjusted parameters, thus maintaining both identification accuracy and reflection detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple photodetector arrays are used to detect beam position, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvebeam position detection accuracyVSAvoiddetection field structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each photodetector array serves multiple functions: it detects beam position, evaluates beam intensity distribution, and contributes to the overall classification decision. This multi-functionality reduces the need for separate dedicated components for each measurement task, thereby improving precision without proportionally increasing device complexity.

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

Solution Approach 2:

The patent merges the functions of multiple photodetector arrays into a unified evaluation system where all arrays work together to classify the received beam. By combining the detection and classification functions across arrays, the system achieves high measurement precision through cooperative operation rather than through complex individual components, thus managing device complexity while improving precision.

Inventive Principle:
Principle #5Merging (Combining)

3Illumination intensity

If laser power is increased to improve beam visibility, then visibility is improved, but safety requirements are violated

Engineering Contradiction:
Improvelaser beam visibilityVSAvoidsafety compliance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The system uses feedback from multiple photodetector arrays to continuously evaluate the received beam characteristics. This feedback mechanism allows the laser receiver to adaptively adjust its detection parameters and classification thresholds based on the actual beam conditions, enabling reliable operation with lower laser powers that comply with safety requirements while maintaining adequate visibility through intelligent signal processing.

Inventive Principle:
Principle #23Feedback

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 approach effectively reduces the risk of incorrect measurements by accurately differentiating between rotating laser beams and reflected beams, improving the reliability of leveling and marking work.

Implementation Method 1

The laser receiver comprises an evaluation unit and at least one detection field with a first measuring range and a second measuring range

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3479061B1Method for comparing a laser beam hitting a laser recipient with a rotating laser beam
Publication Date: 2021.04.07 HILTI AG
  • EP3479061B1 patent drawingFigure 1
  • EP3479061B1 patent drawingFigure 2A
  • EP3479061B1 patent drawingFigure 2B

AI summary

The invention relates to a method for comparing a receive beam (24) incident on a laser receiver (12) with a rotating laser beam (22), which is transmitted by a rotating laser (11) in a direction of rotation (23) about an axis of rotation (21), wherein the laser receiver (12) comprises an evaluation unit and at least one detection field (25) having a first measurement area and a second measurement area. When the receive beam (24) is incident on the at least one detection field (25) of the laser receiver (12), the evaluation unit determines a first receive signal, which represents the time progression of the incident receive beam (24) in the first measurement area, and a second receive signal, which represents the time progression of the incident receive beam (24) in the second measurement area. The evaluation unit determines a direction of movement of the receive beam (24) relative to the laser receiver (12) from the first and second receive signals, and the direction of movement of the receive beam (24) is compared by the evaluation unit with the direction of rotation (23) of the rotating laser beam (22).