Coaxial Optoelectronic Sensor for Rotary Angle Detection

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Solution Overview

Problem

Existing rotary encoders with reflective optical functional principles face challenges in achieving central alignment of light sources and receivers, leading to complex and costly adjustments, significant light intensity loss, and increased space requirements due to the need for beam splitters and mirror systems.

Innovation Solution

A rotary encoder design where the light receiver is positioned coaxially between the light source and the measuring standard, with a through hole in the light receiver acting as a beam-shaping optic, allowing for deflection and polarization of light to improve light distribution and homogeneity on the receiving surface, using metallic coatings for light reflection and scattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If beam splitters and mirror systems are used to redirect the illumination beam path, then central alignment of light source and receiver is achieved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvecentral alignmentVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex beam splitter and mirror system from the optical path. Instead of using multiple optical components to redirect light, the invention positions the light source and receiver in a simplified coaxial arrangement, removing unnecessary elements while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using complex optical elements to redirect the beam path to achieve central alignment, the invention inverts the approach by directly positioning components in a coaxial configuration, allowing light to travel straight through the system without redirection.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If beam splitters and mirror systems are used to redirect the illumination beam path, then central alignment is achieved, but light intensity loss increases significantly

Engineering Contradiction:
Improvecentral alignmentVSAvoidlight intensity loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent removes beam splitters and mirrors from the optical path, eliminating the light intensity losses associated with these components. The direct coaxial configuration allows light to pass through without the reflective and transmissive losses inherent in complex optical redirecting systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If multiple construction levels with non-parallel arrangements are used, then central alignment is achieved, but adjustment complexity and manufacturing cost increase

Engineering Contradiction:
Improvecentral alignmentVSAvoidadjustment complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of using multiple non-parallel construction levels to achieve alignment, the invention inverts the approach by using a single parallel coaxial construction level. This simplifies the mechanical structure and makes adjustment and manufacturing much easier while achieving the same alignment precision.

Inventive Principle:
Principle #13The other way round (Inversion)

4Measurement precision

If such a multi-level structure is used, then central alignment is achieved, but space requirements increase considerably

Engineering Contradiction:
Improvecentral alignmentVSAvoidspace requirements
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent extracts and eliminates the multi-level construction structure, replacing it with a compact coaxial arrangement. This removal of unnecessary structural levels significantly reduces the overall space requirements while maintaining central alignment precision.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design enhances the evaluation of the sensor by actively shaping the beam path, reducing stray light, and allowing for a more compact structure with improved light intensity and polarization analysis, enabling precise angle detection.

Implementation Method 1

the material measure (34) reflects the unpolarized transmitted light in a polarized manner with a polarization direction that corresponds to the current angle of rotation

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

the side walls of the transmitted light-directing unit are light-reflecting with metallic material (48), in particular aluminum, titanium, copper, silver or gold, are coated

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

the side walls of the transmitted light-directing unit are light-reflecting with metallic material (48), in particular aluminum, titanium, copper, silver or gold, are coated, light-scattering or partially light-scattering

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2860497B2Optoelectronic sensor and method for manufacturing the same
Publication Date: 2019.04.10 SICK STEGMANN
  • EP2860497B2 patent drawingFigure 1
  • EP2860497B2 patent drawingFigure 2~2A
  • EP2860497B2 patent drawingFigure 3~4

AI summary

The invention relates to an optoelectronic sensor, in particular for detecting an angle of rotation, comprising a scale (34), a light emitter (20) which emits transmitted light (32) in the directions of transmission, and a light receiver (22) with a light-receiving surface (38) arranged such that the light-receiving surface (38) is located substantially between the scale (34) and the light receiver (22), and the light receiver (22) receives reflected transmitted light (32) as received light (36), wherein a transmit-light-guiding unit is provided which is designed such that a predefined deflection angle of the transmitted light (32) relative to the directions of transmission results when the transmitted light (32) exits the transmit-light-guiding unit, and wherein the transmit-light-guiding unit is provided in the light receiver (22). The invention further relates to a method for manufacturing an optoelectronic sensor.