Scan Driver Reset Unit for Low Frequency Reliability

Solution Overview

Problem

Low frequency driving methods for scan drivers lead to changes in transistor characteristics, reducing the reliability of the scan driver due to prolonged voltage maintenance and increased off-stress on transistors.

Innovation Solution

A scan driver design with a reset unit and specific transistor configurations that turn on during a partial frame period, using a gate start pulse to initialize nodes and terminals, minimizing transistor characteristic changes and maintaining reliability during low frequency driving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If low frequency driving method is used to reduce power consumption, then power consumption is reduced, but transistor characteristics change and reliability decreases

Engineering Contradiction:

Improvepower consumptionVSAvoidscan driver reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The reset unit performs preliminary initialization of nodes before low frequency driving begins, setting them to known states. This preliminary action ensures that even during extended low frequency operation where transistors remain in off-state, the nodes start from a defined condition, preventing characteristic drift and maintaining reliability while allowing power reduction through low frequency operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reset unit is configured to periodically initialize nodes at specific timing intervals during the driving cycle. This periodic reset action counteracts the cumulative effect of off-stress on transistors during low frequency driving, ensuring transistor characteristics remain stable without requiring continuous operation, thus enabling power savings while maintaining reliability

Inventive Principle:

Principle #19Periodic action

2Loss of energy

If voltage is maintained for a certain period in low frequency driving, then power consumption is reduced, but transistor characteristics change

Engineering Contradiction:

Improvepower consumptionVSAvoidtransistor characteristics

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The reset unit performs preliminary initialization of nodes before low frequency driving begins, setting them to known states. This preliminary action ensures that even during extended low frequency operation where transistors remain in off-state, the nodes start from a defined condition, preventing characteristic drift and maintaining reliability while allowing power reduction through low frequency operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reset unit is configured to periodically initialize nodes at specific timing intervals during the driving cycle. This periodic reset action counteracts the cumulative effect of off-stress on transistors during low frequency driving, ensuring transistor characteristics remain stable without requiring continuous operation, thus enabling power savings while maintaining reliability

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10347207B2Scan driver and driving method thereof

Publication Date: 2019.07.09 SAMSUNG DISPLAY CO LTD

AI summary

A scan driver includes a plurality of stages to receive one or more clock signals, each of the plurality of stages to supply a carry signal to a corresponding first output terminal and to supply a scan signal to a corresponding second output terminal, corresponding to a voltage of a corresponding first node, and each of the plurality of stages including a reset unit, the reset unit to initialize the first node, the first output terminal, and the second output terminal, corresponding to a gate start pulse supplied to a corresponding reset input terminal.