Optoelectronic Measuring Device Beam Splitter Tolerance

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Solution Overview

Problem

Existing optoelectronic measuring devices with absolute scales suffer from manufacturing imperfections that affect position measurement accuracy due to non-flat surfaces, requiring precise detector positioning which limits installation tolerance.

Innovation Solution

Incorporation of a pinhole and a retro-reflecting device in the optical assembly, along with a beam splitter, to generate a representative image of the illuminated part of the graduated scale over a range of distances, allowing for increased mounting tolerance and device compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pinhole is used to obtain an image of the graduated scale, then measurement precision is improved, but device complexity increases due to precise positioning requirements

Engineering Contradiction:
Improveposition measurement accuracyVSAvoiddetector positioning precision
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A beam splitter is introduced as an intermediary optical element between the light source and the detector. The beam splitter divides the light path, allowing the detector to receive light from multiple angles and positions. This intermediary component enables the system to maintain precise measurement capability while relaxing the positioning constraints on the detector, as the beam splitter compensates for misalignments by redirecting light appropriately.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from a single-point image generation approach to a multi-position image generation approach by introducing the beam splitter. Instead of requiring the detector to be positioned at one specific point to capture the image through the pinhole, the beam splitter enables the detector to capture light from multiple positions and angles, effectively adding spatial dimensionality to the detection process and reducing positioning sensitivity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If precise detector positioning is required for accurate measurement, then measurement precision is improved, but ease of operation deteriorates due to difficult installation

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidinstallation ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The beam splitter serves as a mediating optical element that decouples the positioning precision requirement from the installation process. By introducing this intermediary, the system can maintain accurate measurements even when the detector is not precisely positioned, as the beam splitter actively redirects light to ensure proper image formation regardless of detector position variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the optical path parameters by introducing the beam splitter, which modifies how light travels from the graduated scale through the pinhole to the detector. This parameter change in the optical system allows for a range of acceptable detector positions while maintaining measurement accuracy, thereby improving installation ease without sacrificing precision.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If optical elements are arranged in a specific way to reduce manufacturing imperfections, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveerror reductionVSAvoidoptical assembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple optical functions into a single beam splitter component. The beam splitter simultaneously performs light division, path redirection, and image formation functions that would otherwise require multiple separate optical elements. This merging reduces the overall optical assembly complexity while maintaining the capability to compensate for manufacturing imperfections in the graduated scale.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The beam splitter is designed as a multi-functional optical element that serves multiple purposes: it divides the light path to create the necessary optical geometry, compensates for positioning variations, and reduces the impact of manufacturing imperfections. This universal component performs several functions that would traditionally require multiple specialized elements, thereby reducing device complexity while improving measurement precision.

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

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

Enhances detector positioning flexibility and maintains measurement accuracy by generating a representative image over a wider range of spacings, improving installation ease and device compactness without compromising measurement precision.

Implementation Method 1

the pinhole acts on the principle of a pinhole camera. Thus, in addition to having the image, there is a greater tolerance during the installation of the device

Methodology Applied
Scientific EffectPinhole camera principle: Photography

Implementation Method 2

a retro-reflecting device in the path of the light between the graduated scale and the pinhole, which allows the light to be concentrated on the focal point marked by the pinhole with greater ease and illumination

Methodology Applied
Scientific EffectRetro-reflection: Retroreflector

Implementation Method 3

a beam splitter in the path of the light between the light source and the pinhole. Part of the light emitted by the light source is reflected in the beam splitter and reaches the graduated scale, where it is reflected, and part of the reflected light passes through the pinhole after passing through the beam splitter

Methodology Applied
Scientific EffectLight reflection and beam splitting: Reflection

Data Source

PatentEP4660589A1Optoelectronic measuring device
Publication Date: 2025.12.10 FAGOR AUTOMATION SCOOP
  • EP4660589A1 patent drawingFigure 1~2
  • EP4660589A1 patent drawingFigure 3~4
  • EP4660589A1 patent drawingFigure 5

AI summary

The invention relates to an optoelectronic measuring device comprising a graduated scale (1), a beam splitter (2), a light source (3) configured to emit light in an emitting direction (A), a pinhole (4) which is traversed by at least part of the light reflected from said graduated scale (1), and a detector (5) configured to receive the light passing through said pinhole (4). The beam splitter (2) is arranged between the light source (3) and the pinhole (4) in the emitting direction (A), and between the graduated scale (1) and the retro-reflecting device (6) in a second direction (B) perpendicular to the emitting direction (A).