Display Power-Line Timing to Prevent Visible Line Off-States
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Solution Overview
Problem
In current display technologies using sub-scan driving, the operation time for each line decreases in proportion to the number of sub-scans, leading to longer off-times that exceed the afterimage persistence in the human eye, causing users to perceive lines as turned off.
Innovation Solution
A display apparatus and method that control power supply to turn on and off power lines multiple times within a frame, distributing on-times using persistence of vision to prevent line off-states from being perceived.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sub-scan driving is used to reduce the number of integrated circuits, then device complexity is reduced, but the operation time for each line decreases causing visible line off-states
Solution Approach 1:
The patent applies periodic action by repeatedly turning each power line on and off multiple times within a single frame period. Instead of a single continuous on-off cycle, each power line undergoes multiple periodic on-off transitions, where the cumulative on-time across all cycles maintains the required brightness while the individual off-periods remain shorter than the human afterimage persistence time, preventing visible line off-states.
Solution Approach 2:
The patent segments the frame period into multiple sub-cycles, with each power line being activated in distributed time slots rather than a single continuous block. This segmentation allows the total on-time to be divided across multiple intervals, ensuring that no single off-period exceeds the human eye's afterimage persistence threshold while maintaining the reduced circuit complexity benefits of sub-scan driving.
2Device complexity
If the number of sub-scans is increased to further reduce integrated circuits, then device complexity continues to decrease, but the off-time for each line becomes longer exceeding afterimage persistence
Solution Approach 1:
The patent uses periodic action to counteract the increased off-times resulting from higher sub-scan counts. By implementing multiple on-off cycles within each frame, the system ensures that individual off-periods remain brief (shorter than afterimage persistence) even when the overall sub-scan frequency is high, thus maintaining the perception of continuous light while achieving greater circuit reduction.
Solution Approach 2:
The patent applies dynamics by adaptively adjusting the timing and distribution of power line activation based on the number of sub-scans. The control system dynamically allocates on-times across multiple cycles, optimizing the distribution to ensure that as sub-scan count increases, the fragmented on-periods are arranged to keep off-gaps below the human afterimage threshold, maintaining visual continuity despite increased circuit simplification.
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 the perception of light emitting devices turning off by repeatedly turning power lines on and off, ensuring each off-time is shorter than the afterimage perception time.
Implementation Method 1
distributing the on-times of a light emitting device using persistence of vision (POV) to prevent a line off-state from being perceived
Data Source
AI summary
Provided is a display apparatus including a substrate, a plurality of light emitting devices arranged in a two-dimensional (2D) matrix on the substrate, a power supply comprising a plurality of power lines configured to provide power to the plurality of light emitting devices, and a controller configured to control the power supply to turn on and off each power line of the plurality of power lines a plurality of times in one frame.