Light Grid Alternating Transmitter Receiver Arrangement
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Solution Overview
Problem
The existing light grid systems have a limited response time due to the sequential activation of transmitter and receiver pairs, which can fail to detect moving objects at high speeds, especially in safety-relevant applications where rapid detection is critical.
Innovation Solution
The arrangement of alternating groups of transmitter and receiver units on each bar, with each group facing an opposite group on the other bar, reduces stray light interference and allows simultaneous activation of multiple pairs, improving detection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmitter and receiver pairs are activated sequentially to avoid stray light interference, then measurement precision is improved, but response time deteriorates
Solution Approach 1:
The light grid is divided into multiple independently controllable transmitter-receiver pairs arranged alternately on the bars. Each pair can be activated simultaneously without interfering with others, allowing parallel detection across multiple passages at once, thus reducing overall response time while maintaining detection accuracy through selective activation of specific pairs
Solution Approach 2:
The system uses periodic scanning of transmitter-receiver pairs in a predetermined sequence. By systematically activating pairs in alternating patterns rather than sequential scanning of all pairs, the system achieves both rapid response and complete coverage, resolving the contradiction between speed and precision
2Loss of time
If multiple transmitter and receiver pairs are activated simultaneously, then response time is improved, but stray light interference increases
Solution Approach 1:
The patent applies local quality by creating alternating patterns of transmitter and receiver units on the bars, where each transmitter is positioned opposite a specific receiver. This local arrangement ensures that when multiple pairs operate simultaneously, only the intended receiver receives light from its paired transmitter, while stray light from other transmitters is directed away from non-corresponding receivers, thus enabling simultaneous activation without interference
Solution Approach 2:
The asymmetric alternating arrangement of transmitter and receiver units creates a non-uniform distribution that prevents stray light from one transmitter pair from reaching the receiver of another pair. This asymmetric positioning ensures that the geometric path of light from any transmitter avoids unintended receivers, allowing simultaneous operation with minimal interference
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 enhances the response time of the light grid by reducing the time required for a scan and minimizing interference, enabling the detection of moving objects and maintaining spatial resolution while preventing false triggers.
Implementation Method 1
transmitter units arranged one above the other in one bar emitting light beams which are received by corresponding receiving units arranged one above the other in the second bar
Implementation Method 2
the detection of an object in the light grid is based on the fact that there is a reduction in the energy input into a given receiving unit because the object in the light beam shadows the receiving unit
Data Source
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AI summary
A light grille (10) has transmitter (12.1-12.14) and receiver (14.1-14.4) units as well as first (11) and second (13) strips that jointly border a passageway to be monitored. The transmitter and receiver units are arranged on the strips. A control and evaluating circuit controls the transmitter and receiver units, sorts out the receiver units so as to test whether light energy beamed into the receiver units meets a switching condition and triggers a safety function, if the beamed light energy does not meet the switching condition. An independent claim is also included for a method for operating a light grille.