Laser Scanner Angle Measurement Using Scattered Light

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Solution Overview

Problem

Conventional laser scanners face challenges in determining angular position reliably and efficiently, leading to increased manufacturing costs, complex installations, and susceptibility to component failures and contamination, particularly due to the use of encoder disks and forked light barriers.

Innovation Solution

The use of scattered light from the emitted light beam for angle measurement, where the angle measuring unit evaluates the periodic variation in scattered light levels to determine the angular position, eliminating the need for additional components like encoder disks and forked light barriers, and utilizing existing components for cost and space savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If encoder disks and forked light barriers are used for angle measurement, then angular position can be determined, but manufacturing costs increase and device complexity increases

Engineering Contradiction:
Improveangular position determinationVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the angle measurement function from separate mechanical components (encoder disk, forked light barrier) and integrates it into the existing deflection unit. The deflection unit itself is used to determine angular position by detecting its own angular position through the position of the emitted light beam, eliminating the need for additional angle measurement components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The deflection unit is given a dual function: it both deflects the light beam for distance measurement and serves as the angle measurement device. By using the same component for both purposes, the patent reduces device complexity while maintaining angular position determination capability.

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

2Measurement precision

If encoder disks and forked light barriers are used for angle measurement, then angular position can be determined, but manufacturing costs increase

Engineering Contradiction:
Improveangular position determinationVSAvoidmanufacturing costs
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the need for separate encoder disks and forked light barriers, extracting the angle measurement function from these expensive components and implementing it through the existing deflection unit, thereby reducing manufacturing costs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses the existing deflection unit, which is already present in the device, instead of adding expensive specialized angle measurement components. This approach uses readily available components to achieve the same measurement function more economically.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If encoder disks are used for angle measurement, then angular position can be determined, but susceptibility to contamination increases

Engineering Contradiction:
Improveangular position determinationVSAvoidsusceptibility to contamination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent removes encoder disks that are susceptible to contamination and replaces them with an angle measurement approach based on the deflection unit's light beam position, which is less vulnerable to environmental contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The deflection unit determines its own angular position by measuring the position of the light beam it emits, without requiring separate angle measurement components that could be contaminated. The system uses its own operational parameters (light beam position) for self-diagnosis.

Inventive Principle:
Principle #25Self-service

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 simplifies angle measurement, reduces component failure risks, and enhances reliability by leveraging existing components, while also allowing for improved angular resolution and contamination detection without additional hardware, thus meeting safety standards for safety laser scanners.

Implementation Method 1

The use of scattered light from the emitted light beam for angle measurement, where the angle measuring unit evaluates the periodic variation in scattered light levels to determine the angular position

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The light is reflected from objects within the monitoring area and analyzed by the laser scanner

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

the distance of the object from the laser scanner is calculated from the light travel time using the speed of light

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3367129B1Optoelectronic sensor and method for detecting objects
Publication Date: 2019.05.15 SICK AG
  • EP3367129B1 patent drawingFigure 1
  • EP3367129B1 patent drawingFigure 2~4
  • EP3367129B1 patent drawingFigure 5~6

AI summary

An optoelectronic sensor (10), in particular a laser scanner, for detecting objects in a monitoring area (20) is described, comprising a light transmitter (12) for emitting a light beam (16), a movable deflection unit (18) for periodically deflecting the light beam (16) into the monitoring area (20), an angle measuring unit (34, 36) for determining the angular position of the deflection unit (18), a light receiver (26) for generating a received signal from the light beam (22) emitted or reflected by the objects, and an evaluation unit (36) configured to evaluate the received signal for detecting the objects. The angle measuring unit (34, 36) is configured to determine the angular position by evaluating scattered light (30) generated by the emitted light beam (16) in the sensor (10).