Optical Sensor Concave Mirror and Reflector Design

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Solution Overview

Problem

Existing optical sensors have limited spatial monitoring capabilities and achieve suboptimal numerical apertures, making it difficult to detect objects across a wide range effectively, especially in close proximity.

Innovation Solution

The use of a concave mirror as receiving optics with a detector positioned in its focal area and separate reflector elements to direct light from close-range objects to the detector, enhancing sensitivity and aperture without increasing complexity or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a multi-focus lens is used to expand the surveillance area, then the detection area is expanded, but the numerical aperture remains suboptimal and the structure becomes more complex

Engineering Contradiction:
Improvedetection areaVSAvoidoptical system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The optical system is segmented into two independent parts: a concave mirror for far-range detection and separate reflector elements for close-range detection. This segmentation allows each component to be optimized for its specific function without requiring a complex multi-focus lens, thereby expanding the detection area while maintaining simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Separate reflector elements are introduced as intermediary components between the close-range objects and the detector. These reflectors redirect close-range light onto the detector, enabling close-range detection without requiring the concave mirror to be redesigned, thus expanding functionality without increasing overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a concave mirror is used for far-range detection, then the aperture is increased, but close-range detection sensitivity decreases

Engineering Contradiction:
ImproveapertureVSAvoidclose-range detection sensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The detection function is segmented into two independent optical paths: one using the concave mirror for far-range detection with high aperture, and another using separate reflector elements for close-range detection. This segmentation allows the concave mirror to maintain its large aperture for far-range applications while the reflectors handle close-range objects, eliminating the trade-off between aperture and close-range sensitivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Separate reflector elements serve as intermediaries that redirect close-range light onto the detector. These reflectors compensate for the concave mirror's inability to effectively detect close-range objects, allowing the system to maintain both high aperture for far-range detection and high sensitivity for close-range detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the receiving optics are positioned close to the transmission axis for close-up monitoring, then close-range detection is improved, but the surveillance area in the direction of receiving optics is limited

Engineering Contradiction:
Improveclose-range detectionVSAvoidsurveillance area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The surveillance area is segmented into close-range and far-range zones, each handled by different optical components. The separate reflector elements are positioned to handle close-range objects while the concave mirror handles far-range objects. This spatial segmentation allows close-range detection without limiting the overall surveillance area, as the concave mirror continues to provide wide-area coverage for distant objects.

Inventive Principle:
Principle #1Segmentation

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 configuration significantly improves sensitivity and expands the detection area for close-range objects while maintaining effective detection across a wide range, achieving comparable or better performance than coaxial systems with a compact and cost-effective design.

Implementation Method 1

receiving optics have a concave mirror for guiding light from objects in the far range

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

detector that is positioned in a focal area of the concave mirror

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

at least one separate reflector element is present, which is set up and positioned to direct the light from objects in the close range to at least one of the detectors

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2101189B1Optical sensor
Publication Date: 2010.12.15 PEPPERL & FUCHS GMBH
  • EP2101189B1 patent drawingFigure 1
  • EP2101189B1 patent drawingFigure 2
  • EP2101189B1 patent drawingFigure 3

AI summary

The sensor (100) has a control and evaluation unit (50) for controlling of a transmitter unit (20) and a receiver unit (30) for evaluation of signals detected from the receiver unit and for reading a switch signal. A light collector has a paraboloid concave mirror (40) for conduction of the light of an object in a distal region (14). The receiver unit has a detector (32), which is positioned in a focal region of the concave mirror. A separate reflector element (61) is arranged and positioned in a close-up region on the detector for conducting the light of the object.