Light Curtain Thermal Expansion Compensation
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Solution Overview
Problem
Light curtains face performance issues due to temperature-dependent expansion differences between electronic cards and housing materials, leading to variable distances between light emitters and receivers, which can result in detection failures, especially at temperature extremes.
Innovation Solution
A light curtain design where at least three electronic cards are fixed relative to the housing using mechanical connecting elements that ensure a constant distance between the first and last light transmitters/receivers, with spring elements to maintain defined distances and minimize play, allowing for cascaded configurations and improved resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If electronic circuit boards are fixed relative to each other and attached to one end of the housing, then the structure is simple and stable, but the distance from the last light emitters and receivers to the housing end varies with temperature changes, creating a variable blind zone
Solution Approach 1:
The optical chain is divided into multiple separately adjustable modules (electronic circuit boards) that can be individually positioned along the housing, allowing each segment to be optimized for thermal expansion compensation while maintaining overall structural stability
Solution Approach 2:
The system allows adjustment of the distance parameters between light emitters/receivers and the housing end, enabling optimization of the blind zone distance for different temperature conditions and application requirements
2Temperature
If additional space is provided to allow for expansion of the optical chain within the housing, then temperature expansion is accommodated, but the blind zone increases and space efficiency decreases
Solution Approach 1:
The mounting system provides dynamic adjustment capability, allowing the optical chain components to be repositioned along the housing to accommodate thermal expansion while maintaining optimal detection distance, rather than requiring fixed additional space
Solution Approach 2:
The electronic circuit boards are arranged in a compact nested configuration within the housing, with each board able to slide or adjust position within the available space, maximizing space utilization while accommodating thermal effects
3Temperature
If the unattached end of the chain moves relative to the housing end with temperature changes, then thermal expansion is accommodated, but detection of objects cannot always be guaranteed
Solution Approach 1:
The system is pre-configured with adjustable mounting positions and spacing mechanisms that allow the optical chain to be initially set up with optimal spacing, which can then be adjusted to compensate for thermal expansion and maintain detection reliability across temperature ranges
Solution Approach 2:
The system incorporates evaluation units that monitor the position and performance of light emitters and receivers, providing feedback that enables adjustment of the optical chain configuration to maintain optimal detection conditions despite temperature-induced movements
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 solution ensures consistent detection performance across temperature changes, reduces blind areas, and allows for space-efficient installation by maintaining a constant distance between light components, enhancing the reliability and usability of light curtains.
Implementation Method 1
the connecting element has at least one spring element... The spring element ensures that the electronic boards are pre-tensioned against each other... The distance between the electronic boards is precisely preset by the spring elements
Implementation Method 2
a transmitting unit with a plurality of light beams emitting light transmitters and a receiving unit with a plurality of light beams receiving light receivers for detecting the objects
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Light curtain (2) with at least two electronic boards (3) arranged one behind the other in a longitudinal direction, on which several light transmitters (4) and/or light receivers (5) are arranged in series, wherein the electronic boards (3) are each connected to one another by a mechanical connecting element (6) and the electronic boards (3) are held in a housing (7), wherein the housing (7) is designed as a profile housing, wherein the first electronic board (3.1) and last electronic board (3.2) are fixed longitudinally at the respective housing end (8), such that the last light transmitter (4) and/or light receiver (5) of the first electronic board (3.1) and the last electronic board (3.2), which is located at the housing end (8), has a fixed defined distance to the housing end (8), wherein the connecting element (6) limits a minimum distance and a maximum distance between the electronic boards (3).