Sequential Measurement of Low-Luminosity Micro-LEDs Using Photodiode Integration
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Solution Overview
Problem
Existing methods for measuring the radiation energy of low-luminosity semiconductor-based light sources, such as micro-LEDs, are slow, insensitive, and prone to measurement errors due to thermal loading and synchronization issues.
Innovation Solution
A method utilizing a photodiode to convert optical pulses into electric charge carriers, which are then integrated and converted into a digital signal for evaluation. This method determines conversion efficiency by the ratio of electric energy to optical energy, enabling faster and more accurate measurements through precise synchronization and sequential activation of light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a photodiode is used to detect short light pulses from semiconductor-based light sources, then the measurement speed can be increased, but the signal/noise ratio deteriorates due to high scanning rates
Solution Approach 1:
The patent applies preliminary action by using a pulsed current source to activate light sources sequentially before measurement, enabling precise timing control. The current source is synchronized with the photodiode detection, ensuring that light pulses are generated at optimal moments for measurement while minimizing thermal loading effects and maximizing signal strength.
2Measurement precision
If the measurement duration is extended to obtain detectable signals from low-luminosity sources, then measurement sensitivity improves, but thermal loading increases and measurement time is limited
Solution Approach 1:
The patent employs periodic action through sequential activation of multiple light sources. Instead of continuously measuring a single source, the system cycles through activating and measuring each light source in turn. This allows the measurement duration to be extended for sensitivity while the sequential nature prevents thermal accumulation in any single source, as each is measured briefly before the next one is activated.
3Adaptability or versatility
If a spectroradiometer is used for spectral measurement, then colorimetric properties can be measured, but the measurement speed decreases and synchronization jitter occurs
Solution Approach 1:
The patent replaces the mechanical scanning mechanism of traditional spectroradiometers with a photodiode-based electrical detection system. By using a pulsed current source to activate light sources sequentially and a photodiode to detect their emission, the system achieves spectral measurement capability without mechanical moving parts, thereby eliminating mechanical limitations and synchronization jitter while significantly increasing measurement speed.
4Productivity
If multiple light sources are measured sequentially, then measurement efficiency increases, but the total measurement time increases due to repeated setup and synchronization
Solution Approach 1:
The patent merges multiple measurement operations into a single integrated process. The pulsed current source simultaneously controls the activation of multiple light sources and the timing of photodiode detection. By combining the current source activation, light emission, and optical detection into one synchronized operation, the system eliminates repeated setup and synchronization steps when measuring multiple sources sequentially, thereby reducing total measurement time while maintaining high efficiency.
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
The method achieves faster, more accurate, and sensitive measurements of low-luminosity semiconductor-based light sources, allowing for sequential measurement of multiple sources in a short time with improved signal/noise ratio and reduced jitter.
Implementation Method 1
the optical pulses are converted by means of a photodiode into electric charge carriers
Data Source
AI summary
Methods and devices for the sequential measurement of a plurality of semiconductor-based light sources that operate faster, more accurately and more sensitively than known methods and devices. In accordance with one implementation, a current pulse is applied by a pulsed current source to the low-luminosity light sources consecutively or simultaneously. The emitted light pulse of LED is converted into electric charge carriers by a photodiode, the electric charge carries are added up by means an integrator circuit, the added-together charge carriers are converted by an A/D converter into a digital signal and the digital signal is forwarded to a measurement and control unit.