Optical Deflection Module for High-Speed Distance Scanning

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Solution Overview

Problem

Current electronic distance measurement (EDM) technologies face limitations in achieving the precision of total stations while also acquiring dense clouds of point measurements at high repetition rates, as seen in geodetic scanners, due to the large inertia of telescopes and cumbersome repositioning requirements.

Innovation Solution

A measurement instrument incorporating a distance measurement module, a splitter, and a deflection module that merges and deflects optical radiation paths to enable precise distance measurements to specific targets and rapid scanning of scenes, combining the precision of total stations with the high repetition rate capability of geodetic scanners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a total station is used to perform distance measurements to specific targets, then measurement precision is improved, but productivity deteriorates due to slow and cumbersome repositioning for each measured point

Engineering Contradiction:
Improvedistance measurement precisionVSAvoidpoint measurement acquisition rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the optical path into separate transmit and receive paths that can be independently deflected. This allows the measurement system to rapidly scan multiple points without mechanically repositioning the entire telescope, thereby improving productivity while maintaining precision through the stable, inertia-free optical deflection mechanism

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical rotation of the entire telescope with an optical deflection system using mirrors or beam splitters. This substitution eliminates the inertia limitations of mechanical rotation, enabling high-speed scanning at thousands of points per second while maintaining the measurement precision of a stationary total station

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a scanner is used to acquire dense clouds of point measurements at high repetition rates, then productivity is improved, but measurement precision deteriorates compared to total stations

Engineering Contradiction:
Improvepoint measurement acquisition rateVSAvoiddistance measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

By segmenting the optical paths and using independent deflection mechanisms, the system achieves high-speed scanning like a scanner while maintaining the precision of a total station. The stable optical reference frame and precise angular encoding preserve measurement accuracy even at high repetition rates

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the low-precision mechanical scanning mechanism with a stable total station mount and high-speed optical deflection. This allows the system to achieve scanner-like productivity while maintaining total station precision through the inertial stability of the fixed telescope

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the telescope is repositioned for each measured point in scanning mode, then measurement precision is maintained, but productivity deteriorates due to large inertia and cumbersome repositioning

Engineering Contradiction:
Improvedistance measurement precisionVSAvoidscanning speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical repositioning of the entire telescope with optical path deflection using mirrors or beam splitters. This substitution eliminates the inertia bottleneck, allowing rapid scanning while the telescope remains stationary and precise

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical intermediaries (mirrors, beam splitters, deflection modules) between the stationary telescope and the target. These intermediaries enable rapid directional changes of the measurement beam without moving the telescope itself, thereby improving scanning speed while maintaining precision

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for precise distance measurements to specific targets and the ability to acquire dense clouds of point measurements at a higher repetition rate, overcoming the limitations of existing technologies by efficiently merging and deflecting optical radiation paths within the instrument.

Implementation Method 1

The transmit path and the receive path are merged in a measurement beam at the splitter

Methodology Applied
Scientific EffectOptical beam merging: Reflection

Implementation Method 2

The deflection module is configured to aim the transmit path and the receive path at the splitter and to deflect at least one of the transmit path and the receive path across an instrument optical axis

Methodology Applied
Scientific EffectOptical deflection: Reflection

Data Source

PatentEP3508816B1Distance measurement instrument with scanning function
Publication Date: 2021.01.06 TRIMBLE AB
  • EP3508816B1 patent drawingFigure 1~2
  • EP3508816B1 patent drawingFigure 3~4A
  • EP3508816B1 patent drawingFigure 4B~4C

AI summary

A measurement instrument is disclosed. The measurement instrument (500) comprises a distance measurement module (505), a splitter (525) and a deflection module (515). The distance measurement module is configured to transmit optical radiation along a transmit path (501) and receive optical radiation along a receive path (502). The transmit path and the receive path are merged in a measurement beam (503) at the splitter. The deflection module is located optically between the distance measurement module and the splitter. The deflection module is configured to aim the transmit path and the receive path at the splitter and to deflect at least one of the transmit path and the receive path across an instrument optical axis (510).