Optoelectronic Sensor Mounting Structure for Thermal Alignment Stability
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Solution Overview
Problem
Plastic sensor housings in optoelectronic sensors exhibit larger measurement tolerances due to thermal expansion, affecting the relative position of light-transmitting and light-receiving elements and degrading measurement accuracy.
Innovation Solution
A sensor design with a sleeve-shaped tube section in the sensor housing that decouples the sensor housing from the carrier unit, using a common fastening point to fix the sensor to an external body, thereby minimizing the impact of thermal expansion on the relative position of the light-transmitting and light-receiving elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic sensor housing is used, then manufacturing cost is reduced, but measurement precision deteriorates due to thermal expansion affecting the relative position of light elements
Solution Approach 1:
The sensor housing is segmented into two functionally independent parts: the plastic sensor housing (for cost-effective manufacturing and mounting) and the separate carrier unit (for precise alignment and thermal stability). The carrier unit is arranged in the interior space of the sensor housing and carries both the light-transmitting element and light-receiving device, isolating them from thermal expansion effects of the plastic housing.
Solution Approach 2:
The carrier unit acts as an intermediary between the plastic sensor housing and the sensitive optical elements. It provides a stable mounting platform for the light elements while being independently positioned within the sensor housing through the sleeve-shaped receptacle system, thereby mediating between the cost-effective plastic housing and the precision optical requirements.
2Stability of the object's composition
If the sensor housing and carrier unit are rigidly connected, then structural stability is improved, but thermal expansion of the plastic housing negatively affects the alignment of light elements
Solution Approach 1:
The rigid connection is avoided by segmenting the housing structure into a sensor housing and a separate carrier unit. The carrier unit is positioned within the sensor housing using a sleeve-shaped receptacle that allows independent positioning, preventing the transmission of thermal expansion forces from the plastic housing to the precision optical elements.
Solution Approach 2:
The carrier unit containing the sensitive optical elements is extracted from direct connection with the plastic sensor housing. It is instead positioned independently within the interior space using the sleeve-shaped receptacle, removing it from the thermal expansion pathway of the plastic housing while maintaining structural stability through the fastening element connection.
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 maintains the precise alignment of light-transmitting and light-receiving elements despite thermal expansion, ensuring accurate measurement results by decoupling the sensor housing and carrier unit through a common fastening point.
Implementation Method 1
a light-transmitting element which is configured to transmit light signals along a transmitted-light path onto the detection region
Implementation Method 2
a light-receiving device which is configured so that the light signals which are reflected from the at least one object in the detection region and which are propagated along a received-light path are detectable
Implementation Method 3
plastic has larger measurement tolerances because, due to the larger thermal coefficient of the plastic, the housing expands more when the temperature changes
Data Source
AI summary
An optoelectronic sensor for detecting an object includes a light-transmitting element which transmits light signals onto a detection region, a light-receiving device which detects the light signals reflected from the object, a sensor housing, and a carrier unit with a circumferentially closed opening. The sensor unit, in a delivery state, forms an interior space for accommodating the light-transmitting element and the light-receiving device, and, in an operating state, has a receptacle for a fastening element which fixes the optoelectronic sensor to an external body. In the delivery state, the carrier unit is arranged in the interior space and accommodates and aligns the light-transmitting element and the light-receiving device. The receptacle is provided as a tube section which completely penetrates the interior space. In the operating state, the tube section is arranged within the closed opening to provide the fastening element in the tube section and thus within the closed opening.