Multi-Die LED Package With Sensing Diodes For Luminance Control
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Solution Overview
Problem
Multi-die LED packages face issues with light emission variability due to manufacturing process variations and aging, leading to unpredictable light intensity and color temperature shifts, which are undesirable in displays and backlight units.
Innovation Solution
Incorporating LED dies that can function as both light-emitting and sensing diodes, connected to a controller that adjusts driving signals based on feedback signals from measuring circuits, allowing for real-time correction of light intensity and color temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LED dies are used in a package to reduce volume and manufacturing costs, then productivity and cost-efficiency are improved, but light emission variability and color temperature shifts increase due to manufacturing process variations and aging
Solution Approach 1:
The patent implements a feedback mechanism where each LED die includes a sensing diode that detects light intensity and converts it to an electrical signal. This feedback signal is sent to a controller that adjusts the driving current for each individual LED die, compensating for variations in light emission and maintaining consistent overall output despite manufacturing variations and aging effects.
Solution Approach 2:
The system dynamically changes the driving parameters (current intensity) of each LED die based on detected light output levels. By adjusting electrical parameters in real-time, the system compensates for manufacturing variations and aging, maintaining consistent light emission from the multi-die package.
2Adaptability or versatility
If individual LED dies have different light emission characteristics, then manufacturing flexibility is improved, but measurement precision and control accuracy deteriorate
Solution Approach 1:
The patent applies local quality by providing individual sensing and control circuits for each LED die within the package. Each die can be independently measured and adjusted, allowing precise control of light intensity for each local element despite manufacturing variations, thereby achieving high overall measurement precision and control accuracy.
3Duration of action of stationary object
If LED light output varies with aging, then device longevity is improved, but light intensity stability deteriorates
Solution Approach 1:
The feedback mechanism continuously monitors light output from each LED die and adjusts driving current accordingly. As LEDs age and their light output naturally decreases, the sensing diodes detect this change and the controller compensates by increasing the driving current, maintaining stable light intensity throughout the extended lifespan of the LEDs.
Solution Approach 2:
The system performs preliminary calibration during manufacturing where each LED die's characteristics are measured and stored. This preliminary action establishes a baseline for each die, enabling the feedback system to make accurate adjustments throughout the LED's operational life to maintain stable light output.
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 solution ensures consistent light output and color temperature across multiple LEDs, improving the reliability and efficiency of backlight units by compensating for individual LED variations and aging effects.
Implementation Method 1
the same or other LED die can be reconfigured electrically to detect at least one physical quantity and transmit a feedback signal representative of the at least one physical quantity
Implementation Method 2
a diode that works as a light-emitting diode for emitting light
Data Source
AI summary
A multi-die LED package comprises a diode that works as a light-emitting diode for emitting light and as a sensing diode for detecting at least one physical quantity. The multi-die LED package is able to provide desired luminance and color independent of aging, temperature or other effects.