LED Backlight Control for Wave Noise Reduction
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Solution Overview
Problem
Simultaneous turning on or off of red, green, and blue LEDs in backlight units for LCD panels generates wave noise, degrading image quality due to harmonic waves, which existing technologies fail to adequately address.
Innovation Solution
A microcomputer-controlled apparatus that sequentially outputs delayed red, green, and blue signals through multiple channels, using PWM dimming pulses to drive LED drivers and switching elements, ensuring LEDs are turned on or off with predetermined intervals, reducing wave noise by synchronizing the operation of LED chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If all LED chips are simultaneously turned on or off, then the control is simple and bright, but wave noise is generated and image quality deteriorates
Solution Approach 1:
The patent applies periodic action by sequentially turning on and off LED chips in different colors (red, green, blue) at different time intervals. Instead of simultaneous operation, each color channel operates in periodic cycles with controlled timing, which eliminates the generation of wave noise while maintaining the simplicity of control through systematic timing sequences.
2Object-affected harmful factors
If LED chips are sequentially turned on with predetermined intervals, then wave noise is reduced, but the control complexity increases
Solution Approach 1:
The patent segments the LED control into separate color channels (red, green, blue) with independent timing control. Each color channel is divided into discrete controllable units that can be activated sequentially. This segmentation allows wave noise reduction through staggered operation while managing complexity by organizing control into modular, color-specific groups rather than individual chip control.
3Measurement precision
If PWM dimming pulses are used to control LED drivers, then brightness control is precise, but the number of control components increases
Solution Approach 1:
The patent applies universality by using PWM dimming pulses as a multi-functional control mechanism that simultaneously achieves brightness control and sequential timing control. The same PWM signal structure is used across all color channels and LED drivers, allowing precise brightness adjustment while maintaining a unified control approach that reduces the need for 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 effectively minimizes wave noise in LCD panels by synchronizing the operation of LEDs, maintaining high color reproduction and brightness uniformity while adjusting overall brightness through RGB dimming, thereby enhancing the reliability of medium and large-sized LCD devices.
Implementation Method 1
a plurality of light emitting diode (LED) drivers for outputting PWM dimming pulses according to the red, green and blue signals inputted through the n number of the channels; a plurality of switching elements for outputting driving currents according to the PWM dimming pulses; and n number of light subunits including a plurality of red, green and blue LED chips
Data Source
AI summary
Provided are an apparatus and method for controlling an operation of an LED in a light unit. The apparatus includes: a micom for sequentially outputting red, green and blue signals delayed by a predetermined interval through n (n>1) number of channels for each color; a plurality of light emitting diode (LED) drivers for outputting PWM dimming pulses according to the red, green and blue signals inputted through the n number of the channels; a plurality of switching elements for outputting driving currents according to the PWM dimming pulses; and n number of light subunits including a plurality of red, green and blue LED chips sequentially driven by the driving currents outputted from the switching elements.