Optical Sensor Synchronization for Extraneous Light Detection
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Solution Overview
Problem
Existing optical sensors fail to detect extraneous light radiation that occurs synchronously with the transmitter's operation, leading to malfunctions during commissioning and subsequent operation.
Innovation Solution
The optical sensor employs a synchronization unit to activate the transmitter and receiver synchronously, with light pulses inverted or time-shifted in different cycles, allowing the extraneous light evaluation unit to detect external light during transmitter pauses, ensuring timely countermeasures can be taken.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitter emits light pulses continuously for object detection, then the monitoring area is continuously covered, but extraneous light radiation occurring synchronously with transmission cannot be detected
Solution Approach 1:
The system uses periodic inversion of light pulse sequences in alternating time intervals. The transmitter emits light pulses in a first time interval, then inverts the sequence in the second time interval. This periodic action creates detection opportunities: during the first interval, object detection occurs; during the second inverted interval, extraneous light can be detected because the expected pulse pattern is different. This resolves the contradiction by periodically creating detection windows for extraneous light without permanently sacrificing object detection coverage.
Solution Approach 2:
The system dynamically changes the light pulse emission pattern by inverting the sequence in alternating time intervals. Instead of a static continuous transmission pattern, the system adapts its transmission characteristics dynamically. The receiver accordingly adapts its evaluation criteria based on whether the current interval is a first or second type. This dynamic adaptation enables the system to distinguish between expected transmitted pulses and extraneous light, resolving the detection reliability issue.
2Object-affected harmful factors
If the transmitter pauses transmission to detect extraneous light, then extraneous light can be detected, but object detection capability is interrupted
Solution Approach 1:
The system implements periodic action by alternating between first time intervals (normal transmission for object detection) and second time intervals (inverted transmission for extraneous light detection). This periodic switching allows both functions to operate without permanent interruption. The receiver evaluates received signals differently based on the current interval type, maintaining object detection reliability during first intervals while enabling extraneous light detection during second intervals.
Solution Approach 2:
The system performs preliminary action by pre-establishing the inverted light pulse sequence in the second time interval before actual extraneous light detection is needed. The inversion is prepared in advance as part of the periodic cycle, allowing the receiver to be ready with appropriate evaluation criteria. This preliminary preparation enables rapid and accurate extraneous light detection when the second interval occurs, without requiring ad-hoc detection methods that would interrupt object detection.
3Object-affected harmful factors
If the light pulse sequence is inverted to enable extraneous light detection, then synchronous extraneous light can be detected, but the complexity of signal evaluation increases
Solution Approach 1:
The system uses periodic inversion of light pulse sequences in alternating time intervals. The transmitter emits light pulses in a first time interval, then inverts the sequence in the second time interval. This periodic action creates detection opportunities: during the first interval, object detection occurs; during the second inverted interval, extraneous light can be detected because the expected pulse pattern is different. This resolves the contradiction by periodically creating detection windows for extraneous light without permanently sacrificing object detection coverage.
Solution Approach 2:
The receiver incorporates feedback mechanisms to evaluate received signals based on the current time interval type. The evaluation unit receives feedback about whether the current interval is a first or second type and adjusts its evaluation criteria accordingly. This feedback loop simplifies the evaluation process by providing clear contextual information about what pattern is expected, making the distinction between transmitted pulses and extraneous light more straightforward despite the inverted sequence.
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 approach enables effective detection of extraneous light throughout the cycle, preventing malfunctions and ensuring error-free operation by allowing countermeasures to be taken during commissioning.
Implementation Method 1
The transmitter and receiver are always activated in specified cycles. To detect objects in a surveillance area, a data evaluation unit uses an evaluation of the received signals from the receiver to check whether a sequence of light pulses emitted by the transmitter is received.
Data Source
Figure 1
Figure 2a~3d
Figure 4~5
AI summary
The invention relates to an optical sensor (1) with at least one transmitter (4), at least one receiver (6), and a data evaluation unit (8). The data evaluation unit (8) uses received signals at the output of the receiver (6) to check whether a sequence of light pulses emitted by the transmitter (4) that forms a code is registered in the receiver (6). A binary switching signal is generated based on this. A synchronization unit (7) is provided, by means of which the transmitter (4) and receiver (6) are activated synchronously within predetermined cycles. The light pulses emitted by the transmitter (4) are inverted and/or time-shifted relative to each other in different cycles. An ambient light evaluation unit (8) is provided, which, to detect ambient light within a cycle, evaluates the received signals of the receiver (6) only during the time intervals in which no light pulses are emitted by the transmitter (4).