LED Lighting Control for Stable Color and Brightness
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Solution Overview
Problem
Conventional LED lighting systems that adjust brightness and color through pulsed current suffer from undesirable effects such as oscillations, false-colored image segments, and discomfort due to pulsating light frequencies, especially in applications like film recordings, and are unable to maintain constant dominant wavelength or brightness across varying conditions.
Innovation Solution
The system supplies LED light sources with direct current instead of pulsed current, allowing for individual control of current strength to maintain a constant dominant wavelength or brightness across varying brightness levels, using characteristic curves to account for temperature and spectral dependencies, ensuring consistent color location and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulsed current is used to control LED brightness, then brightness control is achieved, but pulsating light causes oscillations and discomfort
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to control LED brightness. The LED is switched on and off periodically at a high frequency, creating the perception of continuous dimmed light while actually using discrete on/off cycles. This resolves the contradiction by maintaining brightness control through periodic switching while minimizing visible pulsation effects through appropriate frequency selection.
Solution Approach 2:
The patent implements dynamics by individually adjusting the current parameters for each LED light source based on temperature compensation characteristics. The control unit dynamically modifies the drive current to maintain constant dominant wavelength despite temperature changes, creating an adaptive system that responds to real-time conditions.
2Illumination intensity
If pulsed current is used for brightness adjustment, then brightness varies, but dominant wavelength shifts due to temperature changes
Solution Approach 1:
The patent implements feedback by measuring the temperature of each LED light source and using this information to adjust the drive current parameters. The control unit receives temperature data and automatically compensates for wavelength shifts by modifying the current, creating a closed-loop control system that maintains spectral stability despite thermal effects.
Solution Approach 2:
The patent applies parameter changes by modifying the electrical current parameters (amplitude, pulse width) based on temperature conditions. Instead of maintaining constant current, the system adjusts current parameters dynamically to compensate for temperature-induced wavelength shifts, transforming the operating parameters to achieve spectral stability.
3Manufacturing precision
If individual LED control is implemented, then color mixing precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the lighting system into individually controllable LED modules, each with its own temperature sensor and control parameters. This allows independent optimization of each LED's contribution to the overall light output, enabling precise color mixing while managing complexity through modular architecture.
Solution Approach 2:
The patent implements universality by designing a control unit that handles multiple functions: temperature measurement, wavelength monitoring, and current control for multiple LED types. This multi-functional approach reduces overall system complexity by consolidating control logic into a single intelligent controller rather than requiring separate control circuits for each function.
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 approach eliminates pulsation-related issues, providing stable and consistent light emission with minimal technical effort, maintaining desired color location and brightness without unwanted oscillations or discomfort, even under varying conditions.
Implementation Method 1
at least two electrically controllable LED light sources, which differ from each other in a dominant wavelength of the light produced by them
Implementation Method 2
the light emitted by the arrangement is generated by additive mixing of the light generated by the individual LED light sources
Data Source
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AI summary
The invention relates to a method for operating an arrangement (2) configured to emit light adjustable in its brightness and/or color, the arrangement comprising at least two electrically controllable LED light sources (4, 5, 6) which differ from one another in a dominant wavelength of the light they each produce, wherein the light emitted by the arrangement (2) is generated by additively mixing the light produced by each of the individual LED light sources (4, 5, 6), wherein the LED light sources (4, 5, 6) are individually supplied with direct current such that a predetermined dominant wavelength of the light emitted by the arrangement (2) is constant regardless of the respective brightness of this light and/or that a predetermined brightness of the light emitted by the arrangement (2) is constant regardless of the respective predetermined dominant wavelength of this light.