Display Controller Frame Request Signal for Afterimage Mitigation
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Solution Overview
Problem
When transitioning from a high-frequency display mode to a low-frequency display mode in display devices, such as liquid crystal display devices and organic light emitting display devices, an afterimage of the previous image may remain due to the hysteresis characteristic of the driving transistor in the pixel, leading to undesirable display effects.
Innovation Solution
A controller is designed to prevent afterimages by transmitting a frame request signal when a specific time period exceeds a reference period, allowing for the repeated display of images at a high frequency before switching to a low frequency, thereby mitigating the hysteresis effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display device operates in low-frequency mode to reduce power consumption, then energy efficiency is improved, but afterimages appear due to transistor hysteresis
Solution Approach 1:
The controller performs preliminary actions by transmitting frame request signals to request and display additional frames before switching to low-frequency mode. This preliminary high-frequency frame transmission helps clear the hysteresis effect in the transistor, preventing afterimages when transitioning to power-saving low-frequency operation.
2Reliability
If the controller transmits frame request signals to prevent afterimages, then display quality is improved, but device complexity increases
Solution Approach 1:
The controller uses its existing transmission interface and internal timing mechanisms to generate and transmit frame request signals. This self-service approach allows the controller to prevent afterimages using its own resources without requiring external hardware assistance or separate dedicated circuits, thereby maintaining simplicity.
Solution Approach 2:
The transmission interface, originally designed for standard frame data transmission, is made multi-functional by also handling frame request signal transmission. This universal use of existing components avoids adding dedicated hardware for afterimage prevention, thus not increasing device complexity.
3Measurement precision
If the controller waits for the next frame data to transmit frame request signals, then timing accuracy is improved, but response time increases
Solution Approach 1:
The controller transmits frame request signals at the earliest possible moment after completing current frame data reception, rather than waiting for the next scheduled frame. This preliminary timing ensures accuracy in detecting when to intervene, while minimizing the delay between detecting the need for frame insertion and actually transmitting the request signal.
Data Source
AI summary
A controller includes a reception interface configured to receive first frame data and a first vertical synchronization packet, and a transmission interface configured to transmit a first frame request signal, where when a first period from a time point when the reception interface completes reception of the first frame data to a time point when the reception interface starts reception of the first vertical synchronization packet is longer than a first reference period, the transmission interface transmits the first frame request signal.