Light-Emitting Element Failure Detector Using Instantaneous Current Interruption
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Solution Overview
Problem
Existing light emitting element failure detection methods are affected by variations in voltage Vf due to V-I characteristics, temperature changes, and time, making it difficult to accurately detect short circuits in organic EL elements.
Innovation Solution
A light emitting element failure detector and method that includes a current instantaneous interruption circuit, a voltage detector, and a determiner, which interrupt the current supply to the element and measure the voltage Vf between the anode and cathode during this interruption to determine the presence of a short circuit, setting a threshold that is not influenced by normal state fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage Vf measurement is used to detect short circuit failures, then detection capability is provided, but measurement precision deteriorates due to voltage variations from V-I characteristics, temperature changes, and time
Solution Approach 1:
The patent applies preliminary action by measuring the voltage Vf before the short circuit occurs (in the normal state) and storing this normal voltage value as a reference. This preliminary measurement allows the detection system to compare against a baseline that accounts for normal variations, thereby improving measurement precision without sacrificing detection reliability.
Solution Approach 2:
The patent implements feedback by continuously monitoring the voltage Vf and comparing it against the stored normal voltage value. When the voltage deviates from the normal state (indicating a short circuit), the system provides feedback to trigger failure detection. This feedback mechanism enables precise detection while accommodating normal voltage fluctuations.
2Ease of operation
If a fixed threshold is set for voltage measurement, then detection simplicity is maintained, but reliability deteriorates due to inability to accommodate voltage variations
Solution Approach 1:
The system performs a preliminary measurement of the voltage Vf in the normal state and stores this value as a reference. This preliminary action allows the system to establish a dynamic baseline that accounts for normal variations, enabling reliable detection without requiring complex adaptive thresholds while maintaining operational simplicity.
Solution Approach 2:
The detection system serves itself by automatically measuring and storing the normal voltage value during operation. This self-service mechanism eliminates the need for manual threshold calibration or complex configuration, maintaining simplicity while improving reliability through automatic adaptation to normal voltage variations.
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 reliable detection of short circuits without being affected by voltage variations, ensuring accurate identification and prevention of false positives or negatives due to environmental or operational changes.
Implementation Method 1
a voltage detector that obtains an output of a voltage Vf between the anode and cathode of the light emitting element during a period of the instantaneous interruption
Data Source
AI summary
A light emitting element circuit includes a light emitting element (1), a current supply path to the light emitting element (1), a constant current circuit (2) that supplies a current to the light emitting element (1) via the current supply path, and an electric discharge path that discharges an electric charge accumulated at the light emitting element (1) and at a region connected between the both electrodes when the constant current circuit (2) stops a current supply to the light emitting element (1). A light emitting element failure detector (4) that detects a short-circuit of the light emitting element (1) in a light emitting element circuit includes a current instantaneous interruption circuit (5), a voltage detector (60), and a determiner (62). The current instantaneous interruption circuit (5) is arranged on the current supply path different from the electric discharge path and instantaneously interrupts an electric current that the constant current circuit (2) supplies to the light emitting element (1). The voltage detector (60) obtains an output of a voltage Vf between the anode and cathode of the light emitting element (1) during a period of the instantaneous interruption as a measuring object. The determiner (62) determines the existence of a short-circuit from the output.