Scan Driver for High-Resolution OLED Displays
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Solution Overview
Problem
High-resolution organic light emitting displays face issues with abnormal scan signals due to short scan times and increased load on scan lines at high operating frequencies, leading to irregular images and compensation time shortening.
Innovation Solution
A scan driver design that includes stages receiving start signals, clock signals, and interrupt signals to output scan signals with adjustable pulse widths and overlap periods, ensuring regular image generation by optimizing scan signal timing and overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high operating frequency is used to improve display refresh rate and performance, then productivity and response speed are improved, but scan time becomes too short causing abnormal scan signals and image irregularities
Solution Approach 1:
The patent applies preliminary action by extending the scan signal pulse width before the actual scanning process. The scan driver outputs a scan signal with a pulse width of 2n times one horizontal period (where n≥1), which is longer than the actual scan time required. This preliminary extension ensures that the scan signal remains active long enough to compensate for the short display refresh cycle, preventing abnormal scan signals while maintaining high refresh rates.
2Reliability
If scan signal pulse width is increased to prevent abnormal scan signals, then scan signal regularity is improved, but scan time is extended reducing display refresh rate
Solution Approach 1:
The patent applies dynamics by making the scan signal pulse width adjustable and adaptive. The pulse width is set to 2n times one horizontal period, where n is a natural number that can be configured. This dynamic adjustment allows the system to optimize between scan signal regularity and display refresh rate by changing the value of n, enabling flexible adaptation to different operating conditions without fixed constraints.
3Manufacturing precision
If scan lines are increased to improve display resolution, then manufacturing precision and image quality are improved, but load on scan lines increases causing abnormal scan signals
Solution Approach 1:
The patent applies parameter changes by modifying the scan signal pulse width parameter to 2n times one horizontal period. This parameter change increases the scan signal duration, which compensates for the increased load on scan lines caused by higher display resolution. By extending the pulse width, the system maintains adequate signal strength and timing margins even as the number of scan lines increases, preventing abnormal scan signals while supporting high-resolution displays.
Data Source
AI summary
A scan driver includes a plurality of stages for receiving a first start signal and a second start signal, a first clock signal and a second clock signal, and at least one of two interrupt signals and outputting a scan signal. Each stage includes an up-signal output unit for receiving the first start signal and for outputting a first output signal that is shifted by one horizontal period from the first start signal, a down-signal output unit for receiving a second start signal and outputting a second output signal shifted by one horizontal period from the second start signal, and a scan signal output unit for receiving the first and second output signals and outputting a high-level or low-level scan signal.