Beam Trap Alignment for Laser Measurement Precision

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Solution Overview

Problem

Existing methods for aligning lasers, such as using rulers or scales, are not precise enough to achieve measurements below 1/10mm accuracy with laser beams of 1.5 to 2mm width, and require significant adjustment efforts.

Innovation Solution

A method utilizing a slit-shaped beam trap with facets on a body that absorbs and reflects laser radiation, allowing for precise alignment of a line laser with high accuracy, enabling measurements with repeatability of 0.1 to 0.2mm without special adjustments, by aligning the laser so its radiation is absorbed within the trap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional rulers or scales are used for laser alignment, then the device complexity is low, but the measurement precision is insufficient (cannot achieve below 1/10mm accuracy with 1.5 to 2mm wide laser beams)

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a beam trap as an intermediary element between the laser beam and the measurement scale. The beam trap absorbs the laser beam and provides a visual reference (facet reflection) that enables precise alignment. This intermediary allows measurement precision to improve from 1/10mm to 0.1-0.2mm repeatability without significantly increasing overall device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the parameter of how laser beam position is detected - instead of directly measuring the beam width (1.5-2mm) against a scale, it uses the beam trap to convert the beam position into a visual reference on a facet surface, enabling much finer measurement resolution

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional laser alignment methods are used, then the ease of operation is moderate, but significant adjustment efforts are required to achieve accurate alignment

Engineering Contradiction:
Improveease of operationVSAvoidadjustment time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The beam trap with its slot-shaped depression and facet automatically provides alignment feedback - when the laser beam is correctly positioned, the facet reflection becomes visible through the slot. This self-aligning mechanism eliminates the need for operators to perform complex manual adjustments, significantly reducing adjustment time while improving ease of operation

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a slot-shaped depression beam trap is used, then the measurement precision improves to 0.1 to 0.2mm repeatability, but the manufacturing precision requirements for the beam trap increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoidmanufacturing precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The slot-shaped depression dimensions are specifically designed to match the laser beam width (1.5-2mm), creating an optimal absorption geometry. The facet surface provides a visual reference that compensates for minor manufacturing variations, allowing high measurement precision (0.1-0.2mm repeatability) to be achieved without requiring extremely tight manufacturing tolerances on the beam trap itself

Inventive Principle:
Principle #35Parameter changes

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 method allows for precise and accurate alignment of a line laser relative to a surface, facilitating high-precision measurements and easy implementation, particularly useful for headlight adjustment devices, with the ability to align the laser parallel to a floor surface with high accuracy using multiple bodies.

Implementation Method 1

the radiation of the line laser is absorbed in the beam trap of the body

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the smooth surface of the facet reflects the radiation clearly. This is particularly beneficial for a line laser, since in this case the radiation is visible as a straight line on the facet

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3194887B1Device and method for absorbing radiation
Publication Date: 2019.11.06 ROBERT BOSCH GMBH
  • EP3194887B1 patent drawingFigure 1
  • EP3194887B1 patent drawingFigure 2
  • EP3194887B1 patent drawingFigure 3~4

AI summary

The invention relates to a device and method for absorbing radiation, in particular laser radiation. Said device comprises a base (1) which reflects the radiation incident on its surface (3, 4). The base (1) comprises a beam trap (10) which absorbs the radiation. The device is designed to allow orientation of a laser (12).