Electronic Display Flicker Mitigation via Dual Emission Periods
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Solution Overview
Problem
Electronic displays operating at low refresh rates, such as ten hertz or less, often produce visual artifacts like flickering due to the intermittent emission of light by pixels, which are perceivable by the human eye.
Innovation Solution
Implementing self-emissive pixels with a light-emitting diode (LED) that undergo an on-bias stress and reset process, where the threshold voltage of a transistor is adjusted to ensure consistent light emission, reducing the occurrence of visual artifacts by maintaining equivalent light emission during both refresh and reset phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the refresh rate is reduced to extend battery life, then energy consumption decreases, but visual artifacts such as flickering become more perceptible
Solution Approach 1:
The patent applies periodic action by implementing dual emission periods within a single refresh cycle. The first emission period displays content at normal brightness, while the second emission period displays the same content at reduced brightness. This periodic repetition of content display at different brightness levels creates a persistent visual perception that eliminates flickering artifacts while maintaining low average power consumption throughout the extended refresh cycle.
Solution Approach 2:
The patent utilizes parameter changes by varying the brightness level between two emission periods within the same refresh cycle. The first emission period operates at full brightness to establish the primary visual output, while the second emission period operates at reduced brightness to reinforce the visual perception without consuming full power. This dynamic parameter adjustment allows the display to maintain visual quality at low refresh rates while significantly reducing overall energy consumption.
2Manufacturing precision
If pixels are reset between refresh cycles to prepare for new data, then display accuracy improves, but light emission interruption causes visible flickering
Solution Approach 1:
The patent implements continuity of useful action by maintaining light emission throughout the entire refresh cycle through two sequential emission periods. Instead of completely interrupting light emission during reset operations, the display performs the reset during the transition between the first and second emission periods, ensuring continuous visual output. This approach preserves display accuracy by allowing necessary pixel reset operations while eliminating visible flickering through uninterrupted light emission.
Solution Approach 2:
The patent applies preliminary action by performing the pixel reset operation during the transition phase between emission periods, before the second emission period begins. This timing strategy allows the display to prepare pixels for the next content display while maintaining continuous visual output through the first emission period, thereby preventing visible flickering while ensuring display accuracy is maintained through proper pixel initialization.
3Use of energy by moving object
If a single emission period is used per refresh cycle, then power consumption is reduced, but visual artifacts increase
Solution Approach 1:
The patent applies periodic action by implementing dual emission periods within a single refresh cycle. The first emission period displays content at normal brightness, while the second emission period displays the same content at reduced brightness. This periodic repetition of content display at different brightness levels creates a persistent visual perception that eliminates flickering artifacts while maintaining low average power consumption throughout the extended refresh cycle.
Solution Approach 2:
The patent utilizes parameter changes by varying the brightness level between two emission periods within the same refresh cycle. The first emission period operates at full brightness to establish the primary visual output, while the second emission period operates at reduced brightness to reinforce the visual perception without consuming full power. This dynamic parameter adjustment allows the display to maintain visual quality at low refresh rates while significantly reducing overall energy consumption.
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 the perception of visual artifacts at low refresh rates, enhancing the display quality by maintaining consistent luminance and reducing flickering, making the visual experience more stable and artifact-free.
Implementation Method 1
Each of the pixels may include a light-emitting diode (LED) that may emit light in response to a control signal
Implementation Method 2
the controller may perform an on-bias stress to alter a threshold voltage of the transistor
Data Source
AI summary
An electronic display having pixels and control circuitry to drive the pixels to display image data even during relatively long presentation times without visual artifacts, such as flicker, are provided. The control circuitry may cause the pixel to perform a threshold voltage sampling and pixel programming phase to store image data for the pixel while accounting for a first threshold voltage of the first transistor. Afterward, an on-bias stress phase may cause a threshold voltage of the first transistor of the plurality of transistors to reach a second threshold voltage. Following the on-bias stress phase, a first emission phase may cause the light-emitting diode to emit light in accordance with the image data, and subsequent on-bias stress phases and subsequent emission phases for the duration of the presentation time may take place without a visible flicker artifact.