Light Source Timing Control for Display Panel Transitions
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Solution Overview
Problem
Display devices face issues with visual artifacts such as blurs and jitters due to incorrect transient brightness levels as light valves transition between different light transmittance settings, leading to suboptimal image rendering, especially in motion scenes.
Innovation Solution
A method is introduced to construct specific sequences of light source control pulses that ensure light sources illuminate display panels only after light valves have completed their transitions, using techniques like PWM, PCM, or PDM to drive light sources, thereby maintaining accurate brightness levels and reducing visual artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If light valves transition quickly between different light transmittance settings, then frame rate and response speed are improved, but visual artifacts such as blurs and jitters occur due to incorrect transient brightness levels
Solution Approach 1:
The patent applies preliminary action by delaying the light source activation until after the light valves have completed their transition and settled to the target transmittance. The controller determines when light valve transitions are complete before activating the light source, ensuring that illumination only occurs when the light valves are in their final stable state, thus preventing visual artifacts while maintaining fast effective response
2Productivity
If light sources are activated immediately to illuminate display panels, then productivity and frame rendering speed are improved, but incorrect transient brightness levels cause visual artifacts
Solution Approach 1:
The patent implements feedback by having the controller continuously monitor the state of light valves and use this information to determine when to activate the light source. The controller receives feedback about light valve transition completion and adjusts light source activation timing accordingly, ensuring that illumination is provided only when brightness levels are correct, thus eliminating visual artifacts while maintaining efficient frame rendering
3Measurement precision
If light valves are allowed to settle completely before light source activation, then brightness accuracy is improved, but time delay increases reducing effective frame rate
Solution Approach 1:
The light valve transitions are performed in advance during the frame update period, and the controller monitors completion of these transitions. By the time light source activation is needed, the light valves have already settled to their target states, so no additional settling time is required. This eliminates time delay while maintaining brightness accuracy
Solution Approach 2:
The light valves autonomously complete their transitions to the required transmittance states during the frame update period. The controller simply needs to determine when transitions are complete, rather than waiting for a predetermined time period. This self-service approach minimizes time loss while ensuring brightness accuracy
Data Source
AI summary
A first and a second light valve control values are derived for a first and a second frames, respectively, in a specific region of a display panel based on image data of the first and second frames. It is determined whether a difference between the first and second light valve control values exceeds a light valve control threshold. If so, a light source driving waveform is constructed to comprise a sequence of light source control pulses for controlling one or more light sources designated to illuminate the specific region of the display panel. The sequence of light source control pulses is constrained to start at a start time plus a transition time interval. The transition time interval allows light valves in the specific region of the display panel to complete a transition between the first and second light valve control values.