Gate Driving Circuit Reset Function for Display Panel Noise

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Solution Overview

Problem

High-definition flat panel display devices face image display issues due to noise interference affecting shift registers, leading to incorrect image data output.

Innovation Solution

A gate driving circuit with a voltage level reset function, incorporating pre-charge, pull-up, and pull-down units in shift registers, which switch from a disable to an enable voltage before the display panel transitions from a non-display status to a display status, ensuring accurate scan signal output by setting nodes to a low voltage level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If shift registers are used to control gray levels of pixels, then the display device can control multiple pixels simultaneously, but noise interference causes waveform errors in scan signals leading to incorrect image data

Engineering Contradiction:

Improvesimultaneous pixel control capabilityVSAvoidscan signal accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by resetting the voltage level of the first node to a low level before the shift register outputs the scan signal. This is achieved through a reset unit that includes a reset transistor, which is turned on during a reset period to discharge any accumulated noise or abnormal voltage on the first node, ensuring the node starts in a known clean state before signal generation begins

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary reset unit between the first node and ground, which acts as a mediator to remove noise and abnormal voltages. The reset transistor serves as this intermediary component, providing a controlled path to discharge unwanted charges and restore the node to its proper initial state, thereby isolating the shift register from noise interference

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the display panel switches from non-display status to display status, then the display device can operate normally, but noise interference may affect shift registers causing abnormal scan signals

Engineering Contradiction:

Improvedisplay status switching capabilityVSAvoidnoise interference on shift registers

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a voltage level reset on the first node before the display panel transitions from non-display status to display status. The reset transistor is activated during a predetermined reset period that occurs before the display panel begins normal operation, proactively removing noise that may have accumulated during the non-display state

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by using the reset unit to counteract potential noise interference before it can affect the shift register operation. By discharging the first node to a low level in advance, the system preemptively neutralizes harmful noise effects that might occur during status transitions

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS10643522B2Gate driving circuit and display panel with reset function

Publication Date: 2020.05.05 HANNSTAR DISPLAY CORP

AI summary

In a shift register, a pre-charge unit is configured to receive a first input signal and output a pre-charge signal to a first node, a pull-up unit is configured to output a scan signal to a second node, and a pull-down unit is configured to receive a pull-down control signal. The pull-down control signal switches from a disable voltage to an enable voltage before the display panel switches from a non-display status to a display status.