Optoelectronic Sensor Aperture Laser Ablation Alignment

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Solution Overview

Problem

Optoelectronic sensors face challenges in achieving optimal signal-to-noise ratio due to extraneous light interference, which is exacerbated by component tolerances and limited adjustment quality, leading to suboptimal aperture sizes and signal losses.

Innovation Solution

The method involves generating an aperture on the receiving side that precisely matches the transmitted light spot by measuring the transmitted beam bundle and using a processing laser to create the aperture, allowing for precise alignment and minimization of tolerances, thereby optimizing the signal-to-noise ratio without complex adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a fixed aperture is used in the receiving path, then ambient light can be blocked, but the aperture opening must be larger than optimal to accommodate component tolerances and alignment limitations, resulting in signal losses

Engineering Contradiction:
Improveambient light interferenceVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the parameter of aperture size from a fixed predetermined value to a dynamically optimized value. By measuring the actual transmitted light spot and calculating the optimal aperture diameter based on this measurement, the system adapts the aperture parameter to match the real optical conditions, eliminating the need to oversize the aperture for tolerance compensation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback loop where the transmitted light spot is measured, the optimal aperture is calculated based on this measurement, and the aperture is adjusted accordingly. This closed-loop control ensures that the aperture is optimally sized for the actual optical conditions rather than being based on worst-case tolerance assumptions.

Inventive Principle:
Principle #23Feedback

2Reliability

If the aperture is positioned offset from the transmitted light spot to compensate for alignment errors, then robustness against misalignment is improved, but the aperture opening must be larger, causing signal losses

Engineering Contradiction:
Improverobustness against misalignmentVSAvoidsignal loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent performs preliminary measurement of the actual transmitted light spot position and size before finalizing the aperture settings. By knowing the exact light spot characteristics in advance, the system can precisely position and size the aperture to match the actual beam, eliminating the need for offset positioning that would be required to compensate for unknown alignment errors.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If a matrix receiver with active sub-area programming is used, then ambient light rejection is improved, but the system complexity and alignment limitations due to pixel grid increase

Engineering Contradiction:
Improveambient light rejectionVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the ambient light rejection function from a complex matrix receiver system and implements it through a simple physical aperture in the receiving path. By placing an optimally sized aperture at the focal plane, the system achieves ambient light rejection without requiring matrix receivers or complex electronic control systems.

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 approach enables the production of optoelectronic sensors with improved robustness and higher measurement performance by minimizing extraneous light interference and reducing diffraction phenomena, allowing for precise alignment and optimal aperture size, even in sensitive applications like single-photon detectors.

Implementation Method 1

at least by the light transmitter, transmitting optics, and receiving optics... The receiving optics feature a receiving-side aperture. Initially, however, only an aperture blank is positioned in front of the light receiver... The actual receiving-side aperture is only created in the described, already assembled state, at least by the light transmitter, transmitting optics, and receiving optics.

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

During operation of the optoelectronic sensor, the light transmitter generates a beam of transmitted light with a limited cross-section in a monitoring area of the sensor, and when the beam of transmitted light strikes an object, a spot of transmitted light is created.

Methodology Applied
Scientific EffectLight propagation: Light

Implementation Method 3

In practice, this can be achieved by focusing the received light beam in the receiving path and positioning an aperture at the point where the cross-section is smallest.

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP3939774B1Optoelectronic sensor manufacture
Publication Date: 2022.08.10 SICK AG
  • EP3939774B1 patent drawingFigure 1~2
  • EP3939774B1 patent drawingFigure 3~4
  • EP3939774B1 patent drawingFigure 5~6

AI summary

A method for manufacturing an optoelectronic sensor (10) is described, wherein a light transmitter (12) with a transmitting optic (16) and a light receiver (30) with a receiving optic (26) are arranged relative to each other, the receiving optic (26) having a receiving-side aperture (28), of which initially only an aperture blank (36) is arranged and the receiving-side aperture (28) is only produced from the aperture blank (36) after at least the light transmitter (12) with its transmitting optic (16) and the receiving optic (26) have already been installed. In this process, the light transmitter (12) is activated and geometric information from its transmitting beam (18) is determined, and the receiving-side aperture (28) is produced using this geometric information.