LED Panel Color Correction Using PWM Duty Cycle Balancing
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Solution Overview
Problem
Multiple strings of LEDs are difficult to balance in terms of power, brightness, temperature, and color due to production tolerances, resulting in inconsistent perceived colors across LED panels.
Innovation Solution
A color correction device with a computation engine and software application that computes adjustment values to achieve a reference color by modifying pulse width modulated (PWM) duty cycles, using a reference panel matrix and inverse target panel matrix to drive LEDs and produce uniform color across panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple strings of LEDs are used to increase brightness and coverage, then illumination intensity and area are improved, but color consistency and manufacturing precision deteriorate due to production tolerances
Solution Approach 1:
The system segments the color correction problem by individually measuring and adjusting each LED string's color characteristics. The computation engine processes each string separately, creating individual correction profiles that account for variations in brightness, color temperature, and dominant wavelength, thereby maintaining color consistency across multiple LED strings
Solution Approach 2:
The system changes multiple color parameters simultaneously including PWM duty cycles for RGB channels, brightness levels, and color temperature adjustments. By dynamically adjusting these parameters based on measured characteristics, the system achieves consistent color output across multiple LED strings despite production tolerances
2Illumination intensity
If PWM duty cycles are adjusted to balance brightness across LED strings, then illumination uniformity is improved, but device complexity increases due to computation and control requirements
Solution Approach 1:
The system performs preliminary measurement and characterization of each LED string's color and brightness characteristics during installation or setup. This preliminary action creates a baseline profile that simplifies subsequent adjustments, as the computation engine only needs to apply corrections based on pre-measured data rather than continuously analyzing all parameters
Solution Approach 2:
The computation engine acts as an intermediary between the raw LED strings and the final color output. It receives measurements from color sensors, processes the data through matrix operations, and generates corrected PWM signals, thereby simplifying the overall control architecture by centralizing the complex computational tasks in a dedicated component
3Manufacturing precision
If color correction computation is performed to achieve reference color from target color, then color accuracy is improved, but processing time and measurement precision requirements increase
Solution Approach 1:
The system performs preliminary measurement of LED string characteristics and pre-calculates correction factors during setup or maintenance periods. By storing these correction profiles, the system avoids real-time computation during operation, thereby achieving high color accuracy without impacting performance processing time
Solution Approach 2:
The system replaces complex real-time computational mechanics with pre-calculated correction tables and simplified lookup operations. By substituting intensive matrix operations with pre-computed data, the system maintains high color accuracy while significantly reducing processing time during actual LED control operations
Data Source
AI summary
A color correction device includes a computation engine including a processor and a memory coupled to the processor. The computation engine is configured to receive reference color data. A software application stored in the memory and configured to compute adjustment values needed to achieve the reference color data from a target color. An output configured to output color corrected signals to light emitting diodes (LEDs) to achieve a reference color associated with the reference color data from the target color of the LEDs.