LED Wavelength Compensation via Electrical Phase Analysis
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Solution Overview
Problem
LEDs exhibit variations in output wavelength due to manufacturing defects and temperature changes, which existing technologies struggle to compensate for effectively without complex optical analysis.
Innovation Solution
A method using simple electrical analysis, specifically capacitance-voltage measurements to determine the dominant output wavelength by measuring phase differences, allowing for compensation and control of LED color output, enabling consistent color production across different LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical analysis is used to measure color temperature and light output flux for compensation, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces the optical measurement system (optical sensors, spectrometers) with an electrical measurement system. Specifically, it uses voltage-capacitance (V-C) characteristics and phase measurements of the LED device to determine dominant wavelength, substituting complex optical analysis with simpler electrical characterization that correlates to optical properties.
Solution Approach 2:
The patent introduces an intermediary relationship between electrical characteristics and optical properties. By establishing that voltage-capacitance characteristics and phase measurements correlate to dominant wavelength through a lookup table or model, it uses electrical parameters as intermediaries to infer optical properties without direct optical measurement.
2Measurement precision
If temperature sensors are used to measure LED temperature for compensation, then temperature measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent enables the LED device to self-characterize its properties through electrical measurements. Instead of requiring external temperature sensors to measure LED temperature, the system uses the LED's own voltage-capacitance characteristics and phase measurements to determine operational parameters including dominant wavelength, allowing the device to serve its own characterization needs.
Solution Approach 2:
The patent substitutes thermal measurement mechanisms (temperature sensors, thermal coupling) with electrical measurement mechanisms. By measuring voltage-capacitance characteristics and phase which are influenced by temperature and correlate to dominant wavelength, it replaces direct thermal sensing with electrical characterization that indirectly captures temperature effects.
3Ease of operation
If phase measurement is used to determine dominant wavelength, then measurement simplicity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where phase measurements are taken and compared against a pre-established lookup table or model that maps phase values to dominant wavelengths. This feedback loop allows the system to determine actual dominant wavelength and use this information for compensation, adjusting drive conditions to achieve desired color output despite manufacturing variations.
Solution Approach 2:
The patent changes the measurement parameter from direct optical properties (wavelength, color temperature) to electrical properties (phase, voltage-capacitance characteristics). By measuring phase which is influenced by interface trap density and correlates to dominant wavelength, it transforms the measurement approach to use electrical parameters that are easier to measure but still provide the necessary information for compensation.
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 accurate determination and control of LED wavelength and intensity, compensating for manufacturing variations and aging, ensuring consistent color output and extending LED lifespan.
Implementation Method 1
Lighting using solid-state devices such as LEDs is gaining momentum
Implementation Method 2
during operation, the LED temperature increases and this influences the amount of light output of the LED as well as the dominant wavelength of the output light
Implementation Method 3
determining an electrical characteristic of the LED which is dependent on the voltage-capacitance characteristics
Data Source
Figure 1~2
Figure 3~4
AI summary
A method of determining the dominant output wavelength of an LED, comprises determining an electrical characteristic of the LED which is dependent on the voltage-capacitance characteristics, and analysing the characteristic to determine the dominant output wavelength.