Light Emitting Diode Deterioration Diagnosis via Drive Current Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting and receiving apparatuses face challenges in accurately diagnosing the deterioration of light-emitting elements due to temperature-dependent characteristics, leading to potential inaccuracies in gas detection measurements.
Innovation Solution
The apparatus includes a light-emitting element, a light-receiving element, a controller, and a calculator that supply different drive currents and acquire corresponding detection currents, calculating a ratio-based aging value to generate a signal indicating deterioration, thus enabling accurate calibration and improved detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature-dependent characteristics (forward voltage, reverse current) are used to diagnose deterioration, then deterioration can be detected, but the diagnosing becomes complicated and difficult due to temperature dependencies
Solution Approach 1:
The patent extracts the light emission characteristic from the light-emitting element and uses it as the sole basis for deterioration diagnosis. By taking out only the necessary light emission property and ignoring temperature-dependent electrical characteristics, the diagnosis becomes simpler while maintaining accuracy. The controller measures only the light amount emitted at different drive currents, avoiding the complexity of temperature compensation for voltage measurements.
Solution Approach 2:
The patent changes the measurement parameter from electrical characteristics (voltage, current) to optical characteristics (light amount). This parameter change eliminates temperature dependency issues because light emission intensity can be directly correlated with degradation without being affected by temperature variations in the same way electrical properties are. The system measures light amount at two different drive currents and compares the ratio to initial values to detect deterioration.
2Reliability
If regular yearly calibration is performed, then calibration is scheduled systematically, but calibration may not be performed when necessary since degradation varies by device and environment
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the light emission characteristics and automatically determines when calibration is needed. The controller calculates the ratio of light amounts at different drive currents and compares it to initial calibration values. When deterioration exceeds a threshold, the system generates a calibration notification. This feedback loop ensures calibration is performed based on actual device condition rather than fixed schedules, improving both reliability and precision.
Solution Approach 2:
The system performs self-diagnosis of deterioration by automatically measuring light emission characteristics and comparing them to initial values. The controller itself identifies when calibration is needed without external intervention or fixed scheduling. This self-service capability allows the system to adapt to individual device degradation patterns and environmental conditions, ensuring calibration occurs precisely when necessary for each specific device.
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 method allows for precise detection of light-emitting element deterioration, ensuring accurate calibration and enhanced measurement accuracy by minimizing the impact of temperature dependencies and environmental variations.
Implementation Method 1
a light-emitting element that emits infrared light and a light-receiving element that receives infrared light that has passed through a target gas (such as CO2 gas). The gas detection apparatus can measure the concentration of the gas that absorb infrared light.
Implementation Method 2
a light-receiving element configured to receive light from the light-emitting element and output a detection current corresponding to an amount of received light
Data Source
AI summary
A light emitting and receiving apparatus includes a controller and a calculator. The controller acquires a first detection current from a light-receiving element when supplying a first drive current to a light-emitting element and acquires a second detection current from the light-receiving element when supplying a second drive current to the light-emitting element. The calculator generates a signal indicating deterioration of the light-emitting element when a reference value and an aging value satisfy a deterioration judgment condition, the aging value being a ratio between the first detection current and the second detection current. The detection accuracy of the light emitting and receiving apparatus is thereby improved.