Optical Axis Alignment for Laser Distance Measuring Apparatus

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Solution Overview

Problem

Existing laser distance measuring apparatuses face challenges in accurately adjusting the optical axes of the light projecting and receiving units when multiple light receiving devices are lined up in the vertical direction, leading to offset regions for measurement and reduced detection signal strength.

Innovation Solution

An optical axis adjusting apparatus and method that includes a modulated light beam generating unit, multiple light receiving devices arranged vertically, and first and second targets with varying distances from the laser apparatus, allowing for precise adjustment of the emitting and receiving optical axes to divide the measurement angle range into multiple regions vertically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple light receiving devices are lined up in the vertical direction to divide the detection region, then the measurement angle range can be divided into multiple regions vertically, but the optical axis adjustment becomes difficult and inaccurate

Engineering Contradiction:
Improvemeasurement angle range divisionVSAvoidoptical axis adjustment
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

A retroreflector is introduced as an intermediary object to facilitate optical axis adjustment. The retroreflector reflects light back to the light receiving device along the same path, providing a clear visual indicator for alignment. This intermediary enables accurate optical axis adjustment without requiring complex adjustment mechanisms or procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the optical axes of the light projecting unit and light receiving unit are offset, then the device structure becomes simpler, but the detection signal strength is reduced and measurement accuracy deteriorates

Engineering Contradiction:
Improveoptical axis alignment requirementVSAvoiddetection signal strength
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses itself for alignment verification. The light projecting unit projects light onto the retroreflector, and the reflected light is detected by the light receiving unit. This self-contained alignment verification method allows the system to automatically check and confirm optical axis alignment without requiring external alignment tools or complex adjustment mechanisms, thereby maintaining simple device structure while ensuring strong detection signals.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the optical axes are not accurately aligned, then the device assembly becomes easier, but the measurement precision and detection accuracy are reduced

Engineering Contradiction:
Improvedevice assemblyVSAvoiddetection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

Optical axis alignment is performed preliminarily during the assembly process using the retroreflector as a reference target. By establishing correct alignment before final assembly and operation, the system ensures measurement precision without requiring complex alignment procedures during manufacturing. The retroreflector provides a clear visual reference that guides the alignment process, making assembly easier while maintaining high detection accuracy.

Inventive Principle:
Principle #10Preliminary action

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

Enables accurate detection by ensuring the optical axes of the light projecting and receiving units are aligned, improving detection signal strength and reliability by matching the irradiating and receiving regions, thus enhancing the measurement accuracy in a vertical direction.

Implementation Method 1

a light source and a coupling lens to release a light beam to irradiate the released light beam to a detection target

Methodology Applied
Scientific EffectLight beam propagation: Light

Implementation Method 2

multiple light receiving devices which receive light reflected from the detection target

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 3

a retroreflector that reflects the light beam in a direction opposite to a direction of the released light beam

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 4

an optical device such as a lens, etc., that guides the reflected light to the light receiving device

Methodology Applied
Scientific EffectOptical path guidance: Lens

Data Source

PatentEP2680030B1Optical axis adjusting apparatus and optical axis adjusting method for laser apparatus
Publication Date: 2016.09.21 RICOH CO LTD
  • EP2680030B1 patent drawingFigure 1
  • EP2680030B1 patent drawingFigure 2
  • EP2680030B1 patent drawingFigure 3

AI summary

An optical axis adjusting apparatus for laser apparatus is disclosed that includes a modulated light beam generating unit; light receiving devices(4a, 4b, 4c) ; and targets (9), the multiple light receiving devices are arranged along a vertical direction relative to a releasing direction of a light beam such that a detection target is divided into detection regions, the targets are arranged such that a distance from the laser apparatus in an emitting direction of the light beam varies, a width in a vertical direction relative to an emitting direction of the light beam of a first target is formed smaller than an irradiating width in the vertical direction of the light beam, and one of the light receiving devices is installed at a position which receives only a reflected light from the first target.