Optoelectronic Sensor Triangulation Depth of Field
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Solution Overview
Problem
Existing optoelectronic sensors using the triangulation principle face challenges in achieving compact dimensions while maintaining reliable and sensitive object detection, particularly in ensuring a large depth of field to minimize blur-related magnification across a wide distance range.
Innovation Solution
The optoelectronic sensor design incorporates a transmitting arrangement with a deflecting element that folds the transmitted light path by approximately 180°, allowing for the use of long-focal-length transmitting optics. This configuration, combined with astigmatic transmitting optics and an asymmetric receiving optics aperture, optimizes space usage and enhances sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If long-focal-length transmitting optics are used to increase depth of field, then the depth of field is improved, but the installation space requirement increases
Solution Approach 1:
The patent applies the principle of folding the light path by introducing a deflecting element that redirects transmitted light signals at approximately 180°. This dimensional change in the light path geometry allows the use of long-focal-length transmitting optics while maintaining a compact sensor housing, as the optical path length can be extended without proportionally increasing the physical volume occupied by the optics.
Solution Approach 2:
The deflecting element serves as an intermediary component that enables the light path to fold back on itself. This intermediary allows the transmitting optics to be positioned at a distance that provides long focal length and deep depth of field, while the folded path keeps the overall device footprint compact.
2Measurement precision
If the transmitted light spot is focused sharply on the object, then the detectivity is improved, but the depth of field is reduced
Solution Approach 1:
The patent utilizes astigmatic transmitting optics with specifically designed focal characteristics. By changing the optical parameters to create astigmatism, the system achieves a transmitted light spot that maintains acceptable sharpness across a extended depth of field range, rather than focusing sharply at a single plane. This parameter modification allows the depth of field to be increased while preserving sufficient detectivity.
3Volume of moving object
If the sensor housing is made compact, then the installation space is reduced, but the depth of field is limited
Solution Approach 1:
The patent resolves this contradiction by folding the light path using a deflecting element. This allows the optical components to be arranged in a compact housing while the folded path provides sufficient optical path length for long-focal-length optics, thereby achieving both compact sensor size and extended depth of field.
Solution Approach 2:
The optical system is segmented into distinct functional components (light source, deflecting element, transmitting optics, receiving optics, light receiver) that can be independently positioned and optimized. This segmentation allows the housing to be compact while the optical path between components is extended through the folded geometry.
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
The design achieves a significant increase in the depth of field, allowing for accurate object detection over a larger working distance range without significant blur, while maintaining a compact sensor size and improving sensitivity.
Implementation Method 1
a transmitting optical system configured to focus the transmitted light signals generated by the at least one light source into a transmitted light spot
Implementation Method 2
a receiving optical system configured to focus received signals generated by an object present in the surveillance area by remission of incident transmitted light signals into a received light spot
Implementation Method 3
a spatially resolving light receiver configured to detect the received light spot
Data Source
Figure 1~2
AI summary
The present invention relates to an optoelectronic sensor (10) for detecting objects in a monitoring area according to the triangulation principle, comprising a transmitting arrangement (14) for emitting transmitted light signals into the monitoring area along a transmitted light axis, wherein the transmitting arrangement comprises at least one light source (18) and a transmitting optic (22) which is configured to focus the transmitted light signals generated by the at least one light source into a transmitted light spot, and a receiving arrangement (30) which comprises a receiving optic (32) which is configured to focus received light signals generated by an object present in the monitoring area (12) by reflection of incident transmitted light signals into a received light spot, and a spatially resolving light receiver (34) which is configured to detect the received light spot.wherein the point of impact of the received light spot on the light receiver with respect to a triangulation direction depends on the distance of the object from the optoelectronic sensor, wherein the light receiver is oriented towards the monitoring area and the at least one light source is arranged oriented away from the monitoring area, and wherein the transmitting arrangement comprises at least one deflecting element (26) which is configured to deflect the transmitted light signals initially emitted by the at least one light source in a direction away from the monitoring area towards the monitoring area.