LED Driver Memory Calibration for Color Consistency
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Solution Overview
Problem
Current LED lighting systems face issues with non-uniform color output and brightness due to aging and replacement of LEDs, as well as thermal management challenges, which affect the phosphor and heat radiation.
Innovation Solution
An LED module controlled by a driver module with a memory for storing information about the LED module, allowing for calibration and modification of correction factors to maintain consistent and true-color illumination, including the use of non-volatile memory for retaining settings and a sensor for color measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are used as point light sources to achieve high efficiency and luminous efficacy, then energy efficiency is improved, but uniformity of illumination and color consistency deteriorate
Solution Approach 1:
The system divides the LED lighting into multiple individually controllable channels, each with its own memory storage. This segmentation allows independent calibration and control of each LED channel, enabling compensation for color shifts and brightness variations while maintaining high luminous efficacy of individual LEDs.
Solution Approach 2:
The system stores calibration data in memory that captures the specific electrical and optical parameters of each LED at installation. By referencing these stored parameters and adjusting drive currents accordingly, the system maintains color consistency and uniform illumination while preserving the energy efficiency of LED operation.
2Illumination intensity
If secondary optics are added to diffuse LED light for uniform illumination, then illumination uniformity is improved, but thermal management deteriorates due to impeded heat radiation
Solution Approach 1:
The system performs preliminary calibration of each LED channel before full operation, storing baseline electrical and optical characteristics in memory. This preliminary characterization allows the system to compensate for variations in illumination uniformity through electronic control of individual LED channels, reducing the need for aggressive secondary optics that would impede heat radiation.
Solution Approach 2:
The system replaces reliance on mechanical/optical diffusion elements (secondary optics) with electronic control mechanisms. By individually adjusting the drive current to each LED channel based on stored calibration data, the system achieves uniform illumination through electrical control rather than physical light diffusion, thereby maintaining effective thermal pathways.
3Measurement precision
If calibration measurements are performed to correct color and brightness variations, then color accuracy is improved, but device complexity increases due to memory and control requirements
Solution Approach 1:
The system performs self-calibration by automatically measuring the electrical characteristics and optical output of each LED channel, storing this data in integrated memory, and using this information to automatically adjust drive parameters. This self-service approach achieves high color accuracy without requiring complex external calibration equipment or manual intervention.
Solution Approach 2:
The system merges the calibration measurement functions, memory storage, and control adjustment capabilities into an integrated unit working with each LED channel. By combining these functions rather than implementing them as separate complex subsystems, the system achieves accurate color control with minimized additional complexity.
Data Source
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Figure 3a~3c
AI summary
An apparatus for operating LEDs, having a driver module (1), and an LED module (5), actuated by the driver module (1), having at least one LED, having a memory for storing information about the LED module (5), wherein the memory is contained either in the driver module (1) or in the LED module (5), and the information in the memory can be altered. The information in the memory can be altered on the basis of a calibration measurement.