Laser Gas Analyzer Self-Check Using LED Bypass Detection
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Solution Overview
Problem
Existing laser gas analyzers struggle to accurately determine failure of the light receiving unit due to interference from obstacles like powder dust blocking the optical path, leading to incorrect failure determinations.
Innovation Solution
A laser gas analyzer that intermittently irradiates with laser light and uses a light-emitting diode (LED) to irradiate the photodiode without passing through the measurement target gas, allowing the processor to differentiate between laser and LED light signals to determine the status of the photodiode, thereby accurately identifying failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light receiving unit is irradiated with laser light through the measurement target gas, then the concentration of gas components can be calculated, but obstacles like powder dust may block the optical path causing incorrect failure determination
Solution Approach 1:
The patent segments the light reception function into two distinct modes: laser light reception (for gas concentration measurement) and LED light reception (for light receiving unit status verification). The processor separately evaluates outputs from both light sources, allowing independent assessment of the light receiving unit's functionality without interference from optical path obstacles in the gas measurement path.
Solution Approach 2:
The patent introduces LED light as an intermediary test signal that bypasses the measurement target gas and any potential obstacles in the optical path. This intermediary light source provides a direct test of the light receiving unit's functionality, independent of the gas measurement conditions, enabling reliable failure determination.
2Reliability
If the light receiving unit output is monitored during laser light irradiation, then failure can be detected, but obstacles blocking the optical path cause false failure detection
Solution Approach 1:
The patent segments the detection function into separate evaluation paths: one for laser light output (gas measurement) and another for LED light output (light receiving unit status). By independently monitoring the LED light reception without gas interference, the system achieves precise failure detection that is not confounded by optical path obstacles.
Solution Approach 2:
The patent performs preliminary verification of the light receiving unit's functionality using LED light before or during the gas measurement process. This preliminary action establishes a baseline of the light receiving unit's operational status, allowing the system to distinguish between reduced output caused by obstacles and reduced output caused by actual unit failure.
3Device complexity
If a single light source is used for measurement, then the system is simple, but it cannot distinguish between light blocking by obstacles and light receiving unit failure
Solution Approach 1:
The patent merges two light sources (laser and LED) and their respective reception paths into a single integrated system with unified processing. The processor combines information from both laser light output and LED light output to comprehensively evaluate the light receiving unit's status, achieving reliable failure determination while maintaining system integration.
Solution Approach 2:
The light receiving unit serves multiple functions: it detects laser light for gas concentration measurement and detects LED light for status verification. This multi-functionality allows a single component to perform both measurement and self-diagnosis, reducing the need for separate testing hardware while improving reliability.
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
Enhances the reliability of failure detection by ensuring the photodiode receives light unaffected by obstacles, improving the accuracy and reliability of failure detection without disrupting normal operation.
Implementation Method 1
a photodiode that receives the laser light that has passed through the measurement target gas
Implementation Method 2
a light emitting diode (LED) that irradiates LED light so as to allow the photodiode to receive the LED light without the LED light passing through the measurement target gas
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A laser gas analyzer includes: a laser diode configured to irradiate a measurement target gas with laser light; a photodiode configured to receive the laser light that has passed through the measurement target gas; a processor configured to calculate a concentration of a component contained in the measurement target gas based on an amount of light of the laser light received by the photodiode; and a light emitting diode (LED) configured to irradiate LED light such that the LED light is received by the photodiode without passing through the measurement target gas.