LED Lighting Waveform Control for Flicker-Free Energy Efficiency
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Solution Overview
Problem
Existing lighting technologies face challenges in achieving energy-efficient LED lighting that maintains perceived brightness without flicker, as they struggle to balance circuit delay, human visual perception, and energy consumption.
Innovation Solution
The design employs a waveform-based power supply system for LEDs, where subsets of lighting elements are powered with waveforms out of phase to optimize on and off times based on human visual response and retention times, ensuring energy savings while maintaining constant perceived brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If duty cycle is reduced to dim the light source, then energy consumption is reduced, but perceptible flicker occurs when frequency is below flicker-fusion frequency
Solution Approach 1:
The patent applies periodic pulsing action at frequencies above the flicker-fusion threshold (greater than 20-30 Hz) to dim the LED while preventing perceptible flicker. By operating in the periodic domain at appropriate frequencies, the system achieves energy savings through reduced duty cycle while maintaining steady light perception.
Solution Approach 2:
The patent changes the frequency parameter of the driving signal to exceed the flicker-fusion threshold, and adjusts the duty cycle parameter to control perceived brightness. By optimizing these parameters together, the system reduces energy consumption while maintaining acceptable visual performance without perceptible flicker.
2Loss of energy
If fast switching waveforms are used to reduce energy consumption, then energy efficiency improves, but circuit delay effects prevent immediate light source response
Solution Approach 1:
The patent applies preliminary action by pre-charging the parasitic capacitance of the LED before switching off the driving signal. This ensures that when the switching transition occurs, the light source can respond immediately without delay caused by capacitance discharge, thus maintaining fast response speed while enabling energy-efficient pulsing operation.
3Object-affected harmful factors
If frequency is increased above flicker-fusion frequency to eliminate perceptible flicker, then flicker perception is eliminated, but energy consumption increases due to reduced effective on-time
Solution Approach 1:
The patent employs dynamic adjustment of the driving waveform characteristics, optimizing both frequency and duty cycle parameters based on the LED's response characteristics and human visual perception. By dynamically balancing these parameters, the system eliminates perceptible flicker while minimizing energy consumption through optimized effective on-time.
4Reliability
If parasitic capacitance of LED is considered when selecting waveform, then circuit delay is accounted for, but device complexity increases
Solution Approach 1:
The patent accounts for parasitic capacitance effects by adjusting the waveform parameters (rise time, fall time, pulse width) rather than adding complex compensation circuitry. By modifying the electrical parameters of the driving signal, the system achieves accurate light source activation while maintaining relatively simple device architecture.
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 achieves energy-efficient LED lighting with the same perceived brightness as DC-driven sources while reducing energy consumption and minimizing flicker detection by the human visual system.
Implementation Method 1
Some types of light sources are able to provide fast transitions to a full brightness level... For example, in LEDs, a quantum-well can light up to full brightness in less than 0.1 milliseconds
Data Source
AI summary
A light source includes a plurality of lighting elements arranged to illuminate different regions of visual perception. Circuitry coupled to the light source is configured to supply power to a first subset of the lighting elements according to a first waveform and to a second subset of the lighting elements according to a second waveform out of phase with the first waveform.