LED Arrays with Delay Units for AC Flicker Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED driving systems require additional circuits to operate with AC voltage, leading to increased complexity, reduced efficiency, and flicker issues due to diode characteristics and limitations in driving single LEDs with high voltage AC power.
Innovation Solution
A light emitting device comprising multiple LED arrays connected in parallel to a power source, with at least one delay unit including an inductor connected in series to each LED array, allowing for synchronized current signal distribution and reduced flicker by adjusting the timing of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional circuits (AC/DC converter) are introduced to drive LED with AC voltage, then LED can be driven with normal voltage mode, but device complexity increases and efficiency degrades
Solution Approach 1:
The patent extracts and eliminates the AC/DC converter from the LED driving system by directly connecting LED arrays to AC power source through bridge rectifier, simplifying the circuit configuration while maintaining AC voltage compatibility
Solution Approach 2:
The patent combines multiple LED arrays with different delay times into a single system driven by AC power, merging the functions of power conversion and light emission into one integrated structure without separate DC conversion stages
2Adaptability or versatility
If additional circuits (AC/DC converter) are introduced to drive LED with AC voltage, then LED can be driven with normal voltage mode, but efficiency and reliability degrade due to power conversion process
Solution Approach 1:
The patent removes the AC/DC converter stage entirely, eliminating energy losses associated with power conversion while maintaining the ability to drive LEDs from AC power sources through direct rectification and controlled discharge
Solution Approach 2:
The patent utilizes the periodic nature of AC power cycles with controlled discharge timing, where capacitors charge during voltage peaks and discharge during valleys, creating periodic light emission that improves efficiency by leveraging rather than fighting the AC waveform
3Reliability
If single LED is protected by Zener diode for AC driving, then LED can be protected from reverse voltage, but system size and cost increase
Solution Approach 1:
The patent merges protection functionality into the bridge rectifier configuration and capacitor discharge control system, where the bridge rectifier handles reverse voltage protection and the controlled discharge timing prevents over-voltage stress, eliminating the need for separate Zener diode protection circuits
Solution Approach 2:
The bridge rectifier and capacitor network serve multiple functions simultaneously: power conversion, voltage regulation, reverse polarity protection, and flicker reduction through controlled discharge timing, replacing what would otherwise require multiple separate protection components
4Adaptability or versatility
If single LED is driven in uni-directional 60 Hz mode, then AC voltage can be used, but flicker characteristics degrade and light quality problems occur
Solution Approach 1:
The patent implements controlled periodic discharge of capacitors during each AC voltage cycle, creating multiple light emission phases within each half-cycle that increase the duty cycle and reduce the depth of light output modulation, thereby minimizing visible flicker
Solution Approach 2:
The patent maintains continuous light emission by ensuring that capacitor discharge periods overlap or closely follow each other across multiple LED arrays with different timing, eliminating gaps in light output and providing smooth, continuous illumination throughout the AC cycle
5Adaptability or versatility
If high voltage AC power is used to drive single LED with Vf of 3-4V, then power source flexibility improves, but effective driving becomes limited
Solution Approach 1:
The patent segments the high voltage AC power into multiple lower voltage LED arrays connected in series strings, where each array operates within its optimal voltage range while the combined system can handle high voltage AC input through proper configuration of multiple series-connected arrays
Solution Approach 2:
The patent combines multiple LED arrays with different forward voltage requirements into a single driven system using bridge rectifier and capacitor discharge control, allowing high voltage AC power to effectively drive arrays with various Vf values by controlling the discharge timing and voltage distribution across the bridge configuration
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
The solution effectively reduces flicker and improves efficiency by ensuring that all LED arrays emit light at different times, minimizing the duration of non-emission and enhancing overall light quality and reliability when driven by AC voltage.
Implementation Method 1
at least one delay unit including an inductor connected in series to each LED array
Data Source
AI summary
Light emitting devices. A light emitting device including a power source; and a plurality of light emitting diode (LED) arrays coupled to the power source unit; and at least one delay unit. Each delay unit is coupled to a corresponding light emitting diode array of the light emitting diode arrays.