Optical Sensor Aperture Arrangement Suppressing Side Lobes
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Solution Overview
Problem
Optical sensors face reliability issues due to side lobes in light beams not being emitted exactly along the optical axis, leading to impaired object detection, and existing optics units are structurally complex.
Innovation Solution
The optical sensor employs a diaphragm arrangement with at least two diaphragms of different inner and outer diameters and a tube element around its outer edge to control beam guidance, preventing parasitic reflections and side lobes from affecting detection, while maintaining a compact and simple structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical units are used to shape and focus light beams, then object detection function is achieved, but side lobes are generated due to imprecise beam emission along the optical axis
Solution Approach 1:
The patent extracts and eliminates the harmful parasitic reflections by introducing aperture arrangements that block side lobes generated within the housing. The aperture arrangement selectively removes unwanted reflected light components while allowing the main beam to pass through, thereby extracting the harmful element from the optical path.
Solution Approach 2:
The aperture arrangement acts as an intermediary element between the transmitter/receiver and the housing walls. It mediates the optical path by allowing the main beam to pass while blocking parasitic reflections, thus preventing direct interaction between the light beams and the reflective housing surfaces that generate side lobes.
2Reliability
If conventional optical units are used to shape and focus light beams, then object detection function is achieved, but the structural complexity increases
Solution Approach 1:
The patent merges the aperture arrangement with the housing structure itself, integrating the beam-shaping and parasitic-reflection-blocking functions into the existing housing design. This integration eliminates the need for separate complex optical units while achieving the desired optical performance.
Solution Approach 2:
The housing structure is designed to serve multiple functions: it provides mechanical support, defines the optical path, and through the integrated aperture arrangement, actively blocks parasitic reflections. This multi-functionality reduces the need for additional dedicated components, thereby simplifying the overall structure.
3Device complexity
If light beams are emitted without precise optical axis alignment, then the optical sensor structure is simpler, but detection reliability deteriorates due to side lobes
Solution Approach 1:
The patent converts the potentially harmful parasitic reflections into a controlled situation by using the housing walls themselves as part of the solution. The aperture arrangement is positioned to utilize the existing housing structure to block side lobes, turning the housing from a source of problems into an active participant in solving the side lobe issue.
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 significantly enhances the reliability of object detection by effectively guiding light beams and reducing parasitic reflections, achieving improved detection accuracy with minimal structural complexity.
Implementation Method 1
The tube element reflects, in particular, side lobes of the light rays in a controlled manner in directions determined by the geometry of the tube element
Implementation Method 2
The apertures have different inner and outer diameters, so that different aperture effects are achieved. The multiple apertures ensure a defined beam path for the light rays
Data Source
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AI summary
The invention relates to an optical sensor for detecting objects in a monitoring area, comprising at least one transmitter (4) emitting light beams (3) having an optical axis (12) and at least one receiver (6) having an optical axis (12) and configured to receive light beams (3). Each transmitter (4) and receiver (6) is associated with an aperture arrangement (10) comprising at least two apertures (13, 15, 17) arranged along the optical axis (12) with different inner and outer diameters. A tubular element is provided around the outer edge of at least one aperture (13, 15, 17).