Coaxial Laser Sight Alignment for Distance Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Hand-held laser distance measuring devices face challenges in aligning visible laser beams for inexperienced users, especially in high ambient luminance conditions, due to optical crosstalk and beam visibility issues, which affect measurement accuracy and user comfort.

Innovation Solution

The optical axis of the sight is aligned coaxially with the visible laser beam, with deflection optics designed to be predominantly reflective for the laser wavelength and transmissive for ambient light, allowing the user to see a sharp point of light indicating the laser beam's position on the target, and providing additional information like distance values through the optical aiming device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the optical axis of the sight is aligned coaxially with the visible laser beam, then alignment accuracy is improved, but device complexity increases due to additional deflection optics

Engineering Contradiction:
Improvealignment accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the sight and laser beam emission into a single coaxial optical axis, merging the aiming function with the laser emission function. This integration allows the user to see the laser beam position directly through the sight while maintaining alignment accuracy, resolving the contradiction between precision and complexity by functional integration rather than separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces deflection optics as an intermediary element that redirects the laser beam path to be visible through the coaxial sight. These deflection optics act as a mediator between the laser source and the user's eye, enabling the user to observe the laser beam position without requiring separate viewing mechanisms, thus improving alignment accuracy while managing complexity through a dedicated intermediary component.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If laser power is increased to improve beam visibility in high ambient luminance conditions, then beam visibility is improved, but safety risks increase

Engineering Contradiction:
Improvebeam visibilityVSAvoidsafety risks
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent uses deflection optics as an intermediary to make the laser beam visible through the coaxial sight without increasing laser power. The deflection optics redirect a portion of the laser beam to be visible to the user's eye while maintaining the original safe laser power levels, thus resolving the contradiction between visibility and safety by using optical redirection rather than power increase.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs wavelength-selective deflection optics that utilize different optical properties at different wavelengths. By selecting specific wavelength ranges for the laser beam and using deflection optics with appropriate spectral characteristics, the system enhances beam visibility through color/wavelength differentiation without increasing power, thereby maintaining safety while improving visibility in high ambient luminance conditions.

Inventive Principle:
Principle #32Color changes

3Reliability

If beam splitting optics are used to separate transmitted and received beams in coaxial arrangements, then optical crosstalk is reduced, but device complexity increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidoptical component quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the beam splitting function with the existing coaxial optical path by integrating deflection optics that work together with the beam splitting optics. This combination allows the system to maintain the simplicity of coaxial arrangement while achieving effective beam separation, resolving the contradiction between reliability and complexity through synergistic integration of optical components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces deflection optics as an intermediary element that works in conjunction with beam splitting optics to separate the transmitted and received beams. This intermediary component enhances the beam separation capability without requiring a complete redesign of the coaxial structure, thus improving measurement accuracy while managing device complexity through a coordinated optical system.

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

This configuration enables easy and accurate alignment of the visible laser beam for inexperienced users, improving measurement accuracy and user comfort by reducing eye strain and glare, while maintaining safety within laser power limits.

Implementation Method 1

deflection optics, which direct the laser beam emitted by the measuring device in the direction the outlet opening deflects having

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

deflection optics for a narrow range around the wavelength of the visible laser beam λ ± Δλ is designed to be predominantly reflective and transmissive for the ambient light coming from the target object

Methodology Applied
Scientific EffectSelective optical transmission: Filter (optical)

Implementation Method 3

a beam splitter 46. The beam splitter 46 is designed in such a way that it is designed to transmit light with the wavelength λ and polarization direction of the laser beam and to reflect light with a polarization direction perpendicular to the polarization direction of the laser beam

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

beam splitter 46. The beam splitter 46 is designed in such a way that it is designed to transmit light with the wavelength λ and polarization direction of the laser beam and to reflect light with a polarization direction perpendicular to the polarization direction of the laser beam

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 5

a beam source 21, a receiving device 23 with a detector 24 and second beam shaping optics 25 and an evaluation device 26. The transmitting and receiving devices 20, 23 are arranged biaxially, i.e. their optical axes run parallel to one another

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 6

receiving device 23 with a detector 24 and second beam shaping optics 25 and an evaluation device 26

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2261589B1Laser device for electro-optical distance measurement
Publication Date: 2014.03.19 HILTI AG
  • EP2261589B1 patent drawingFigure 1a
  • EP2261589B1 patent drawingFigure 1b
  • EP2261589B1 patent drawingFigure 2

AI summary

Laser device (60) for electro-optical measurement of the distance of a target object (4) to a reference mark (10-15, 18) comprising a housing (9), wherein the housing (9) has an exit opening (66) for coupling a laser beam (65) out of the laser device (60), a measuring device (41) which emits a laser beam (64) and determines a distance value from the received beam (69) coming from the target object (4), a display device (6) for displaying the distance value, an operating device (7) for operating the laser device and for starting the distance measurement, and an optical aiming device (61) for aligning the laser beam (65) onto the target object (4), wherein the direction (71) in which a user looks into the optical aiming device (61) is aligned parallel to the optical axis of the laser beam (65) coupled out of the laser device (60) via the exit opening (66).