Optoelectronic Sensor Refractive Cylindrical Lens Alignment

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Solution Overview

Problem

Existing optoelectronic sensors, particularly code readers, face challenges in effectively visualizing their detection area without a visualization monitor, leading to difficulties in aligning the sensor correctly for accurate code reading, especially with the limitations of diffractive optical elements (DOEs) which are inefficient and suitable only for a narrow wavelength range.

Innovation Solution

The use of refractive cylindrical lenses to generate a light pattern by focusing light from multiple sources onto multiple lines, allowing the detection area to be identified through crossing, surrounding, or corner markings, with a microlens field providing flexible and efficient illumination, enabling precise alignment without the need for adjustments and supporting a wide wavelength range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a diffractive optical element (DOE) is used to generate target patterns, then the detection area can be visualized, but the efficiency is limited and production is demanding

Engineering Contradiction:
Improvetarget pattern visibilityVSAvoidproduction complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent replaces the diffractive optical element (DOE) with a refractive optical element consisting of multiple cylindrical lenses. This substitution eliminates the need for complex DOE manufacturing processes while achieving the same target pattern generation function. The refractive element can be produced using standard lens manufacturing techniques, significantly improving ease of production.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the optical mechanism from diffraction to refraction. By using cylindrical lenses that refract light to form lines, the system achieves target pattern generation without relying on the wavelength-specific diffraction properties of DOEs. This parameter change enables broader wavelength applicability and simplifies manufacturing.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If a diffractive optical element (DOE) is used to generate target patterns, then the detection area can be visualized, but the wavelength range is limited

Engineering Contradiction:
Improvetarget pattern visibilityVSAvoidwavelength range
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the diffractive optical element (DOE) with a refractive optical element consisting of multiple cylindrical lenses. This substitution eliminates the need for complex DOE manufacturing processes while achieving the same target pattern generation function. The refractive element can be produced using standard lens manufacturing techniques, significantly improving ease of production.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the optical mechanism from diffraction to refraction. By using cylindrical lenses that refract light to form lines, the system achieves target pattern generation without relying on the wavelength-specific diffraction properties of DOEs. This parameter change enables broader wavelength applicability and simplifies manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If cylinder lenses are used to generate light patterns, then the detection area can be marked with crossing lines, but the device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidoptical element complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the optical element into multiple cylindrical lenses with different orientations. Each lens generates a specific line pattern, and by combining multiple such lenses, the system creates a comprehensive target pattern with crossing lines. This segmentation approach achieves precise alignment markings while keeping individual lens elements simple and manufacturable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the optical element to serve multiple functions: it generates target patterns for visualization, provides alignment references through crossing lines, and can be produced using standard lens manufacturing techniques. This multi-functionality reduces the need for separate components and simplifies the overall system.

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

This solution provides a cost-effective and versatile method for marking the detection field, enabling precise alignment and decoding of both one-dimensional and two-dimensional codes, with improved optical output and reduced requirements for the light source, suitable for various applications including camera-based code readers.

Implementation Method 1

The solution is based on the basic idea of generating the light pattern refractively. For this purpose, several cylindrical lenses are used that focus the light from the light source of the target device on several lines.

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The lighting device initially generates a homogeneous rectangular light field, from which a pattern that is dissimilar to itself is then created with the aid of a pattern generation element

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 3

a target device that makes the detection area visible with a crosshair or a similar, localizable luminous marker

Methodology Applied
Scientific EffectLight interference: Interference

Data Source

PatentEP2620894B1Optoelectronic sensor and method for recording object information
Publication Date: 2014.01.08 SICK AG
  • EP2620894B1 patent drawingFigure 1~2
  • EP2620894B1 patent drawingFigure 3a~3c
  • EP2620894B1 patent drawingFigure 4a~4b

AI summary

An optoelectronic sensor (10) is described, comprising a light receiver (16) for converting received light from a detection area (12) into an electrical signal, an evaluation unit (18) for obtaining information about objects in the detection area (12) from the electrical signal, and a targeting device (22) comprising at least one light source (24) and a pattern-generating element (28) to make the detection area (12) visible by means of a light pattern (36). The pattern-generating element (28) comprises several cylindrical lenses (30, 32, 34) such that the generated light pattern (36) has several lines (38) from which the position of the detection area (12) can be derived.