Laser Scanner Tilted Mirror 3D Scanning

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Solution Overview

Problem

Existing laser scanners face challenges in efficiently scanning three-dimensional spatial areas without the need for complex mechanical movements or additional deflection units, which increase costs and complexity, and often have limited scanning ranges and distorted scanning planes.

Innovation Solution

The introduction of a secondary deflection unit that moves along a different axis relative to the primary deflection unit, allowing for a rotating prism to create a three-dimensional scanning pattern by superimposing movements, enabling a wider monitoring range with a simple and low-maintenance wireless power supply and data transmission system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an additional deflection unit is used to expand scanning range, then three-dimensional scanning capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvescanning rangeVSAvoidoptical and mechanical complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dimensionality change by tilting the rotating mirror about a second axis that is inclined at an angle between 45° and 60° relative to the first rotation axis. This angular inclination transforms the conventional planar scanning motion into a three-dimensional conical scanning pattern, enabling the laser beam to cover a spatial volume rather than just a two-dimensional plane, thus expanding scanning capability without adding deflection units

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

Solution Approach 2:

The patent implements dynamics by making the mirror tilt angle adjustable and variable during operation. The tilt angle can be changed dynamically to adapt the scanning cone geometry to different application requirements, providing flexibility in controlling the scanned volume and enabling optimization between scanning range and resolution without mechanical reconfiguration

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If the scanning angle range is expanded beyond facet angular portion, then monitoring range is improved, but scanning plane distortion increases

Engineering Contradiction:
Improvemonitoring rangeVSAvoidscanning plane distortion
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

By inclining the mirror tilt axis at a specific angle (45°-60°) relative to the rotation axis, the patent transforms the scanning geometry from a distorted planar pattern to a conical scanning volume. This dimensional transformation naturally distributes the scanning angles more evenly across the focal plane, reducing distortion effects while expanding the effective monitoring area beyond the limitations of individual facet angular portions

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

3Adaptability or versatility

If multiple deflection units are used for three-dimensional scanning, then scanning volume is improved, but transmission and reception signal losses increase

Engineering Contradiction:
Improvescanning volumeVSAvoidtransmission and reception signal losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the second deflection function from a separate physical component and integrates it directly into the rotating mirror by tilting it about an inclined axis. This eliminates the need for additional oscillating mirrors or deflection units that would introduce extra optical interfaces and associated signal losses, while still achieving three-dimensional scanning capability through the conical beam pattern generated by the single tilted rotating mirror

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution allows for expanded three-dimensional scanning capabilities with reduced mechanical complexity and optical losses, enabling precise distance measurement and position data capture in a flexible and efficient manner.

Implementation Method 1

evaluates the remitted or reflected light

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the propagation time from the scanner into the scenery and back is measured and distance data are calculated using the speed of light

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

a rotating mirror or a polygon wheel to periodically scan a surveillance plane

Methodology Applied
Scientific EffectLight reflection from rotating mirror: Reflection

Implementation Method 4

A rotating prism is placed in the light path between the rotating mirror and the transmitter/receiver unit. As a result, the scanning beam is periodically pivoted

Methodology Applied
Scientific EffectLight refraction through prism: Refraction

Data Source

PatentEP3032275B1Optoelectronic sensor and method for detecting objects
Publication Date: 2017.05.17 SICK AG
  • EP3032275B1 patent drawingFigure 1
  • EP3032275B1 patent drawingFigure 2
  • EP3032275B1 patent drawingFigure 3

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 main drive (28), a first deflection unit (28) moved by the main drive (28) for periodically deflecting the light beam (16), an auxiliary drive (36) for moving the first deflection unit (18) or a further deflection unit (48) for additionally deflecting the light beam (16), a light receiver (36) for generating a received signal from the light beam (22) emitted or reflected in the monitoring area (20), and an evaluation unit (46) designed for detecting the objects based on the received signal. The auxiliary drive (36) is arranged to move in conjunction with the first deflection unit (18).