Display Timing Controller Reduces Flicker via PWM Scrambling
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Solution Overview
Problem
Electronic display devices, particularly those using micro-LEDs or OLEDs, face challenges in accurately depicting low gray levels due to short current pulses, leading to visual artifacts like flicker, which are not effectively mitigated by existing methods.
Innovation Solution
Implementing a timing controller that increases the emission rate frequency by partitioning frames into sub-frames and using pulse-width modulation, along with a scrambler circuit to evenly distribute pulse-width modulated signals throughout the frame, thereby reducing visual artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If higher current values are provided to μ-LED for low gray levels, then gray level accuracy is improved, but visual artifacts like flicker increase
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to drive μ-LEDs with periodic current pulses instead of continuous current. By controlling the duty cycle of these periodic pulses, the system achieves accurate gray level representation while distributing the current delivery over time, preventing the flicker and visual artifacts associated with short high-current pulses.
Solution Approach 2:
The patent implements dynamics by transitioning from static gray level control to dynamic PWM control. The system dynamically adjusts the pulse width and frequency of current signals to μ-LEDs based on the desired gray level, enabling precise control while maintaining stable visual output without flicker.
2Object-generated harmful factors
If emission rate frequency is increased to reduce visual artifacts, then flicker is reduced, but power consumption increases
Solution Approach 1:
The patent uses periodic PWM action to achieve high effective emission rates without proportionally increasing power consumption. By modulating the duty cycle of periodic pulses, the system can achieve high temporal resolution for artifact reduction while the average power consumption remains controlled through the pulse width modulation ratio.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the frequency and duty cycle of PWM signals. This allows the system to optimize between emission rate and power consumption by changing temporal parameters rather than simply increasing overall power delivery, achieving high effective refresh rates with controlled energy usage.
3Use of energy by moving object
If short current pulses are used for low gray levels, then power efficiency is improved, but gray level accuracy deteriorates
Solution Approach 1:
The patent resolves this contradiction by using periodic PWM pulses where the duty cycle precisely controls the average current. Even though individual pulses are short, the periodic nature with controlled duty cycle allows accurate gray level representation while maintaining power efficiency, as the μ-LED only draws current during the pulse duration.
Solution Approach 2:
The patent changes the temporal parameters of current delivery by using PWM with variable duty cycles. This allows the system to maintain short pulse durations for power efficiency while using frequency and duty cycle modulation to achieve precise gray level control, resolving the trade-off between power efficiency and accuracy.
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 enhances the display's ability to accurately depict low gray levels without significant visual artifacts, improving power efficiency and reducing flicker, while maintaining high emission rates without increased power consumption.
Implementation Method 1
light-emitting diodes such as organic light-emitting diodes (OLEDs), micro-LEDs (μLEDs), or active matrix organic light-emitting diodes (AMOLEDs) may be employed as pixels to depict a range of gray levels for display
Data Source
AI summary
A display device may include pixels that display image data. The display device may also include a circuit that receives pixel data having a gray level for at least one pixel, such that the pixel data corresponds to a frame of the image data and the frame includes sub-frames. The pixel data causes the circuit to provide at least one current pulse to the at least one pixel according to a first order of the sub-frames. The circuit may also receive a second order of the sub-frames, such that the second order is mapped with respect to the first order, and at least one current pulse is provided to the at least one pixel according to the second order. As such, visual artifacts depicted on the display are reduced.