Mirror Pyramid for Laser Scanner Uniform Sensitivity

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Solution Overview

Problem

Laser scanners with non-uniformly inclined mirror facets struggle to achieve optimal scanning range and accuracy due to varying reception sensitivity across different scanning compartments, leading to measurement errors and reduced performance.

Innovation Solution

A mirror pyramid design with at least four mirror facets, each inclined differently relative to the axis of rotation, is optimized to minimize surface scattering and equalize reception sensitivity across scanning compartments, allowing for the generation of multiple diverging scanning fans with a single transmission beam, and a method for producing such a pyramid using a 3D printer to ensure dynamic balance and precise inclination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a mirror pyramid with differently inclined mirror facets is used to generate multiple diverging scanning fans, then the scanning range and application versatility are improved, but the reception sensitivity varies across different scanning compartments leading to measurement errors

Engineering Contradiction:
Improvescanning rangeVSAvoidreception sensitivity uniformity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by optimizing the specific inclination angles of individual mirror facets. Each mirror facet is assigned a predetermined inclination angle from a set of different angles, and the sequence of facets around the rotation axis is carefully selected to minimize scattering of receiving surfaces. This local optimization ensures that while each facet creates a different scanning fan, the overall reception sensitivity remains uniform across all compartments.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs preliminary action by pre-calculating and pre-selecting the optimal sequence of mirror facets before the laser scanner operates. The computer generates multiple data sets representing different sequences, calculates the scattering of receiving surfaces for each sequence, and selects the optimal sequence in advance. This preliminary optimization ensures uniform reception sensitivity without requiring real-time adjustments during operation.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple diverging scanning fans are generated with a single transmission beam, then the productivity and scanning efficiency are improved, but the receiving surfaces of mirror facets scatter leading to non-uniform reception sensitivity

Engineering Contradiction:
Improvescanning efficiencyVSAvoidreceiving surface distribution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses preliminary action by pre-calculating the optimal arrangement of mirror facets using a computer. The computer generates multiple data sets representing different sequences of mirror facets, calculates the scattering of receiving surfaces for each sequence, and selects the optimal sequence in advance. This preliminary computational optimization ensures that the mirror pyramid is manufactured with the correct facet sequence to minimize receiving surface scattering.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by systematically varying the inclination angles of mirror facets. At least two mirror facets have different inclinations relative to the rotation axis, creating multiple diverging scanning fans. The specific inclination angles are selected from a predetermined set, and their sequence around the axis is optimized to maintain uniform reception sensitivity while maximizing scanning efficiency.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the point of incidence sweeps out equal arc angles on each mirror facet, then the scanning fan angles are equalized, but the sequence of mirror facets must be precisely controlled to minimize scattering

Engineering Contradiction:
Improvescanning fan angle consistencyVSAvoidmirror facet sequence control
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs preliminary action by using a computer to pre-calculate and pre-determine the optimal sequence of mirror facets. The computer generates multiple data sets representing different sequences, evaluates each sequence's scattering characteristics, and selects the optimal sequence before manufacturing. This preliminary computational work simplifies the manufacturing process by providing clear guidance on the exact sequence and inclination of each facet.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating multiple data sets that represent different possible sequences of mirror facets. Each data set is a virtual copy of the mirror pyramid configuration with a specific sequence arrangement. The computer evaluates these copied configurations and selects the optimal one, allowing for virtual testing and optimization before physical manufacturing.

Inventive Principle:
Principle #26Copying

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 solution enhances the measurement sensitivity and range of laser scanners by ensuring uniform reception sensitivity across compartments, reducing measurement errors and improving scanning accuracy, while allowing for the generation of multiple scanning fans with consistent fan angles.

Implementation Method 1

The transmitted beam directed at the rotating mirror pyramid is periodically scanned by the pyramid over a scanning angle range

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the received beam reflected by the surroundings is received back in the same direction

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4270087B1Laser scanner and mirror pyramid and method for producing the same
Publication Date: 2024.12.11 RIEGL LASER MEASUREMENT SYSTEMS
  • EP4270087B1 patent drawingFigure 1
  • EP4270087B1 patent drawingFigure 2
  • EP4270087B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a laser scanner (1) for scanning an environment, comprising a laser transmitter (11) for emitting a transmitting beam (12), a laser receiver (16) for receiving an environment-reflected receiving beam (15), and a mirror pyramid (2) arranged in the beam path of the transmitting and receiving beams (12, 15) with mirror facets (7i) inclined differently relative to the axis of rotation (5), wherein, during operation, the point of incidence (C) of the transmitting beam (12) on the mirror pyramid (2) sweeps out an equal arc angle (δi) on each mirror facet (7i) in the direction of the axis of rotation. The invention further relates to a mirror pyramid (2) for this laser scanner and a method for its manufacture.