LED Backlight Sequential Switching to Reduce Wave Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The simultaneous turning on or off of red, green, and blue LEDs in backlight units for LCD devices generates wave noise, distorting images due to compound harmonics.
Innovation Solution
An apparatus and method that sequentially delays the turn-on or turn-off times of red, green, and blue LEDs using switching units and a control unit, preventing simultaneous activation or deactivation, thereby reducing wave noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If red, green, and blue LEDs are simultaneously turned on or off, then the backlight unit operates with simple control, but wave noise is generated due to compound harmonics
Solution Approach 1:
The patent applies periodic action by sequentially turning on and off the red, green, and blue LEDs in a repeated cycle. The control unit outputs driving pulses to switch units with predetermined time delays, creating a periodic sequence where LEDs are activated one after another rather than simultaneously. This sequential periodic operation eliminates compound harmonics and wave noise while maintaining simple control through systematic timing.
2Object-generated harmful factors
If red, green, and blue LEDs are sequentially turned on or off with time delay, then wave noise is reduced, but control complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the time delay relationships between driving pulses for different color LEDs. The control unit is configured to output pulses with predetermined time delays before execution, so the sequential timing is prepared in advance. This allows the complex sequential control to be implemented through pre-planned timing parameters rather than complex real-time adjustments.
Solution Approach 2:
The patent applies parameter changes by adjusting the time delay parameter between driving pulses for different LED colors. Instead of changing the fundamental control structure, the invention modifies the timing parameter (time delay) to achieve sequential operation. This parameter-based adjustment reduces wave noise while keeping the control system relatively simple, as it only requires timing adjustments rather than structural complexity.
3Loss of time
If simultaneous turning on or off is used, then the synchronization time is long, but image distortion occurs due to wave noise
Solution Approach 1:
The patent applies periodic action with sequential LED activation to resolve the contradiction between synchronization time and image quality. By periodically turning on LEDs in a fixed sequence (red, then green, then blue) with predetermined delays, the system achieves faster effective synchronization that prevents wave noise. The periodic sequence ensures that LEDs are activated in a controlled manner within a short time window, eliminating image distortion while maintaining efficient synchronization.
Data Source
AI summary
Provided are an apparatus and method for driving LEDs. The apparatus comprise a plurality of red, green, and blue light emitting diodes connected, respectively; switching units turned on or off by an inputted pulse to turn on or off the red, green and blue light emitting diodes, respectively; and a control unit outputting respective pulses to sequentially delay a turn-on or turn-off time between the switching units.