Light Grid With Offset Transmitter Rows and Reflector
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Solution Overview
Problem
Existing light grids face challenges in detecting small objects reliably due to detection gaps, the need for active elements on both sides, and a complex arrangement of transmitters and receivers.
Innovation Solution
A light grid design with transmitters and receivers arranged alternately in two offset rows, using a reflector at one edge to ensure complete illumination and differential signal evaluation for reliable object detection, allowing for a structurally simple setup with all components housed on one side and controlled by a single evaluation unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmitters and receivers are arranged in separate housings on opposite edges to form beam axes, then object detection is achieved when beam axes are interrupted, but active elements are required on both sides increasing structural complexity
Solution Approach 1:
The patent combines transmitters and receivers into a single housing arrangement on one side of the monitored area, eliminating the need for separate housings on opposite edges. This merging reduces structural complexity while maintaining detection functionality through the use of a reflector on the opposite side to complete the optical path.
Solution Approach 2:
The patent introduces a reflector as an intermediary element on the opposite edge to redirect transmitted light back to receivers. This mediator enables the optical path to be completed without requiring active detection elements on both sides, thereby reducing structural complexity while preserving detection reliability.
2Illumination intensity
If transmitters emit at a wide angle to generate secure overlap and uninterrupted light band, then complete illumination is achieved, but detection gaps still occur in the area in front of the transmitters
Solution Approach 1:
The patent transitions from a single-row linear arrangement to a two-dimensional alternating grid pattern with transmitters and receivers in offset rows. This dimensional change allows light beams to cross and overlap more effectively, eliminating detection gaps in front of transmitters while maintaining complete illumination of the monitored area.
Solution Approach 2:
The patent divides the detection system into multiple alternating rows of transmitters and receivers, creating a segmented grid structure. This segmentation allows each transmitter to be associated with multiple receivers across different rows, ensuring comprehensive coverage and eliminating blind spots through overlapping beam patterns.
3Reliability
If a large number of receivers are located very close together, then complete coverage is achieved, but the arrangement becomes complex and difficult to manage
Solution Approach 1:
The patent segments receivers into multiple alternating rows with transmitters, where each receiver is positioned in offset rows rather than concentrating all receivers in a single dense array. This segmentation distributes receivers more evenly across the housing, reducing local density while maintaining complete coverage through the alternating pattern.
Solution Approach 2:
The patent arranges receivers in a two-dimensional alternating grid pattern across multiple rows rather than concentrating them in a one-dimensional dense line. This dimensional distribution reduces the number of receivers that must be located very close together while achieving complete coverage through the extended alternating pattern.
4Measurement precision
If transmitters are activated one after the other with differential signal evaluation, then small objects can be detected quickly and reliably, but the control system becomes more complex
Solution Approach 1:
The patent implements periodic activation of transmitters in an alternating sequence rather than continuous simultaneous operation. This periodic action allows each transmitter to be activated one after the other with its associated receivers, enabling differential signal evaluation to detect small objects while reducing overall system complexity through time-multiplexed operation.
Solution Approach 2:
The patent employs dynamic sequential activation of transmitter-receiver pairs rather than static simultaneous operation. This dynamic approach allows the system to switch between different transmitter-receiver combinations in sequence, enabling precise differential measurement of small objects while simplifying control through systematic temporal coordination.
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
Enables quick and reliable detection of small objects with uninterrupted illumination and enhanced detection reliability through differential signal evaluation and threshold value comparison, reducing structural complexity and detection gaps.
Implementation Method 1
a reflector arranged at the opposite second edge of the monitored area... when the monitoring area is free, the transmitted light beams of the respective transmitters are guided via the reflector as received light beams to the adjacent receivers
Data Source
Figure 1~2b
Figure 3a~3d
Figure 4~5
AI summary
The grid has receivers (5, 5', 5'') provided for transmitters (2, 2') such that transmission light beams (3, 3') of the transmitters are guided through a reflector (7) as received light beams (4, 4', 4'') at the receivers in a free monitoring area. The transmitters are individually activated one after the other such that a difference of the received light beams of the receivers is evaluated for each activated transmitter. An object (6) e.g. small object, in the monitoring area is identified when the difference of received light beams is different from a reference value.