LED Self-Calibration via Photo-Sensitivity Measurement
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Solution Overview
Problem
LED arrays used in displays and lighting systems face challenges in maintaining uniform brightness and color over time due to variations in light output and wavelength among individual LEDs, leading to costly and time-consuming recalibration processes, especially in applications like LED billboards and LCD backlights.
Innovation Solution
The use of photo-sensitivity measurements to determine emission parameters such as intensity and wavelength of LEDs, allowing for adjustment of light output to maintain precise color and intensity across LED groups, reducing the need for binned LEDs and on-site pixel-by-pixel calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photo-sensitivity measurements are used to determine emission parameters, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by using the LED's own photo-sensitivity to measure its emission parameters. The LED under test acts as both the light source and the detector, eliminating the need for external calibration equipment. This self-measurement approach simplifies the calibration system while improving manufacturing precision through direct feedback on emission characteristics.
Solution Approach 2:
The patent implements multi-functionality by enabling LEDs to serve dual purposes: as light sources for illumination/display and as photo-detectors for self-calibration. This universal approach allows the same component to perform both emission and detection functions, reducing the need for specialized calibration equipment and simplifying the overall system.
2Productivity
If photo-sensitivity measurements are used to determine emission parameters, then productivity is improved, but measurement precision requirements increase
Solution Approach 1:
The patent employs feedback by using the measured photo-sensitivity data to adjust and optimize LED emission parameters. The self-measurement process provides direct feedback on actual emission characteristics, enabling real-time calibration adjustments that improve productivity while maintaining measurement precision through iterative optimization.
Solution Approach 2:
The patent applies parameter changes by utilizing the photo-sensitivity measurement to determine and adjust emission parameters such as intensity and wavelength. This dynamic parameter adjustment based on self-measurement enables rapid calibration (improving productivity) while the feedback mechanism ensures measurement precision is maintained through continuous optimization.
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 enables cost-effective and efficient maintenance of uniform color and brightness in LED systems by compensating for variations in LED performance during manufacturing and over the lifespan of the devices, minimizing the need for frequent recalibration and specialized LEDs.
Implementation Method 1
providing a first LED, using the first LED to receive light from a light source, determining an emission characteristic from the first LED or from the light source based upon the light received by the first LED
Data Source
AI summary
LED calibration systems and related methods are disclosed that use the photo-sensitivity of LEDs to correct for variations between LEDs during initial production and over the lifetime of systems using LEDs. The disclosed systems and methods include methods to set the color or color temperature produced by a group of LEDs during the manufacturing of a device such as a lamp, an LED display, or an LCD backlight, and maintaining such color or color temperature over the operating life of such a device. The methods involve measuring the intensity and/or wavelength of light produced by each LED within a group of LEDs and adjusting an amount of light generated by the LEDs to produce precise color and intensity from the group of LEDs. Two methods that operate some of the LEDs in photovoltaic or photoconductive mode to measure the light intensity produced by other LEDs in the group are presented. The first method uses an additional light source as a reference and determines the light intensity emitted from each LED relative to such reference, while the second method determines the light intensity emitted from each LED relative to each other.