Display Device Flicker Reduction via Variable Power Control
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Solution Overview
Problem
Display devices using a simultaneous emission scheme experience visible flicker when the image refresh rate is changed, as existing technologies fail to effectively manage power voltage levels and emission periods in response to varying refresh rates.
Innovation Solution
A display device and method that vary the voltage levels and supply times of power lines during a frame period, with pixels emitting light when the second power is changed to a low level, and the number of these changes and supply times adjusted based on the image refresh rate, including a driving transistor to control current to a light-emitting element and capacitors to manage voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image refresh rate is changed in a simultaneous emission scheme, then power consumption is reduced at low frequencies, but visible flicker occurs
Solution Approach 1:
The patent applies periodic action by dividing the frame period into multiple control periods with alternating emission and non-emission sections. Pixels simultaneously emit light in emission sections and remain off in non-emission sections, creating a periodic lighting pattern that reduces flicker visibility while enabling low-frequency operation. The number of control periods per frame is adjusted based on refresh rate, maintaining consistent emission timing across different frequencies.
Solution Approach 2:
The patent implements dynamics by making the number of control periods and the duration of emission sections variable based on the image refresh rate. When refresh rate changes, the system dynamically adjusts the structure of the frame period to maintain consistent emission timing characteristics, preventing flicker while adapting to different power consumption requirements.
2Illumination intensity
If pixels simultaneously emit light in a simultaneous emission scheme, then display brightness is improved, but flicker becomes visible when refresh rate changes
Solution Approach 1:
The patent structures each frame period into multiple control periods, each containing emission and non-emission sections. Pixels simultaneously emit light during emission sections across all control periods, maintaining high display brightness through coordinated simultaneous emission while the periodic alternation with non-emission sections prevents flicker visibility.
Solution Approach 2:
The patent ensures continuous useful action by organizing emission sections to occur at consistent intervals across multiple control periods within each frame. This maintains continuous light emission patterns that preserve brightness while the structured periodicity prevents flicker, allowing the display to operate effectively at low refresh rates.
3Use of energy by moving object
If the number of control periods is increased to reduce refresh rate, then power consumption decreases, but emission timing consistency becomes difficult to maintain
Solution Approach 1:
The patent dynamically adjusts the number of control periods per frame based on the target refresh rate. When operating at lower refresh rates, more control periods are included in each frame, but the emission sections are positioned to occur at consistent relative intervals. This dynamic reconfiguration maintains emission timing consistency despite variations in the total number of control periods.
Solution Approach 2:
The patent changes structural parameters of the frame period, specifically the number of control periods and the duration of emission sections, based on the refresh rate requirement. By adjusting these parameters while maintaining consistent emission timing intervals, the system achieves both reduced power consumption and stable emission timing across different operating conditions.
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
Prevents visible flicker by ensuring pixels emit light at a constant cycle regardless of refresh rate changes, maintaining uniform luminance and reducing power consumption.
Implementation Method 1
a light emitting element connected between a second node and the second power line
Data Source
AI summary
A display device including: a power supply configured to supply a first power, a second power, and a third power to a first power line, a second power line, and a third power line, respectively, wherein each of the first power, the second power and the third power varies in voltage level during one frame period; and pixels connected to at least one of scan lines and data lines, and connected to a common control line, the first power line, the second power line, and the third power line, wherein the pixels simultaneously emit light when the second power is changed to a low level, and a number of times the second power is changed to the low level during the one frame period changes in response to an image refresh rate.