Optical Distance Measurement Device with Focus Shifting Mechanism

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Solution Overview

Problem

Existing optical distance measurement devices face challenges in accurately measuring distances to both scattering and reflective target objects, particularly due to issues with laser beam alignment, radiation power management, and compatibility with external optics like telescopes, leading to measurement errors and inefficiencies.

Innovation Solution

A device with a focus shifting mechanism that adjusts between different states to accommodate various target types, combined with a damping device and beam shaping optics, allows for stable operation across a temperature range and enables the laser beam to be coupled into external optics, ensuring precise distance measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a collimated laser beam is used for distance measurement to scattering target objects, then measurement accuracy to scattering targets is improved, but the radiant power becomes too high causing detector overload for reflective target objects

Engineering Contradiction:
Improvedistance measurement accuracy to scattering targetsVSAvoiddetector overload from excessive radiant power
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic adaptability by providing multiple beam shaping optics with different beam divergence characteristics and multiple receiving beam shaping optics with different field of view angles. The system dynamically selects the appropriate optical configuration based on the target type (scattering or reflective) to optimize measurement while preventing detector overload.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key optical parameters including beam divergence angle and field of view angle to adapt to different target types. By selecting optics with appropriate parameters, the system maintains measurement accuracy for scattering targets while reducing radiant power for reflective targets to prevent detector overload.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a collimated laser beam is precisely aligned to the center of a single retroreflector, then distance measurement accuracy to reflective targets is improved, but any misalignment causes parallel offset of the received beam missing the detector

Engineering Contradiction:
Improvedistance measurement accuracy to reflective targetsVSAvoidmeasurement reliability under alignment variations
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent provides dynamic adaptability through multiple beam shaping optics and receiving beam shaping optics with different characteristics. The system can switch between configurations to accommodate alignment variations and different target types, maintaining reliable measurements regardless of precise alignment conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the field of view angle parameter by selecting different receiving beam shaping optics. This parameter change allows the system to tolerate larger angular deviations from perfect alignment while maintaining measurement accuracy, thereby improving reliability under alignment variations.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If scattering optics are used to expand the laser beam for different target objects, then adaptability to various targets is improved, but extraneous light attenuation is insufficient and coupling into external optics becomes unsuitable

Engineering Contradiction:
Improveadaptability to different target objectsVSAvoidextraneous light interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic adaptability by providing multiple beam shaping optics with different beam divergence characteristics and multiple receiving beam shaping optics with different field of view angles. The system dynamically selects the appropriate optical configuration based on the target type to optimize both adaptability and extraneous light rejection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies different optical properties to different parts of the system - transmitting beam shaping optics for beam expansion and receiving beam shaping optics for field of view control. This local differentiation allows simultaneous optimization of target adaptability and extraneous light attenuation.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If multiple beam shaping optics with different expanding properties are provided for adaptation, then versatility for different targets is improved, but device complexity increases

Engineering Contradiction:
Improveversatility for different target typesVSAvoidnumber of optical components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the multiple beam shaping optics and receiving beam shaping optics to serve universal functions - the same set of optics can be used for both scattering and reflective targets by appropriate selection. This multi-functionality reduces the need for entirely separate optical systems for different target types.

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

Solution Approach 2:

The patent implements dynamic selection among a limited set of optical configurations rather than requiring continuous adjustment. This discrete switching approach provides versatility for different target types while keeping the overall device complexity manageable through a finite number of switchable components.

Inventive Principle:
Principle #15Dynamics

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 provides stable and accurate optical distance measurements to both scattering and reflective target objects, reduces the risk of detector overdrive, and allows for seamless integration with external optics, enhancing measurement precision and efficiency.

Implementation Method 1

a laser beam source (21), which is designed as a first electro-optical component and emits a laser beam

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

a beam shaping optics (15), which is designed as a second laser beam shaping optics and transforms the laser beam into a focused laser beam

Methodology Applied
Scientific EffectOptical focusing: Focusing

Implementation Method 3

the focus shifting device (16) is adjustable between a first state in which the focus shifting element (33) is arranged outside the beam path of the laser beam, and a second state in which the focus shifting element (33) is arranged within the beam path of the laser beam

Methodology Applied
Scientific EffectOptical path adjustment:

Implementation Method 4

a detector (22), which is designed as a second electro-optical component and receives a reception beam scattered or reflected by a target object

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP4031901B1System with a device for optically measuring distance to both scattering and reflecting targets
Publication Date: 2024.06.26 HILTI AG
  • EP4031901B1 patent drawingFigure 1
  • EP4031901B1 patent drawingFigure 2
  • EP4031901B1 patent drawingFigure 3

AI summary

The invention relates to an apparatus (11) for the optical measurement of a distance to a target object that is formed as a diffusing target object or a reflecting target object, said apparatus having a distance measuring device (13) and an adjusting device (14). In the distance measuring device (13), a laser beam is generated which is adjusted with the aid of the adjusting device (14) to an external optical unit (12). The adjusting device (14) comprises a beam-shaping optical unit (15) and a focal shift device (16).