Shift Register Leakage Prevention in Touch Display Panels

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Solution Overview

Problem

Existing display panels with touch-control functions suffer from reduced display quality due to leakage phenomena in shift registers, leading to abnormal gate signal output and pixel display issues.

Innovation Solution

A shift register design incorporating a forward/backward scan-control module, interlock module, pull-down module, output module, and reset module, utilizing multiple voltage terminals to prevent leakage and maintain voltage levels, ensuring normal gate signal output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If touch-control stage is inserted in the middle of display stage, then touch control and display functions are implemented simultaneously, but voltage leakage occurs in shift register leading to abnormal gate signal output

Engineering Contradiction:

Improvetouch control and display functionsVSAvoidgate signal output

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The shift register circuit is divided into multiple functional modules: forward scan module, backward scan module, interlock module, pull-down module, and reset module. Each module performs a specific function to control voltage levels at different nodes, preventing leakage while enabling both touch control and display operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interlock module acts as an intermediary between the forward scan module and backward scan module. It uses intermediate nodes (first node, second node) to transfer and control voltage levels, ensuring that when one scan direction is active, the other is properly inhibited, thus preventing voltage leakage that would cause abnormal gate signal output.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If forward scan and backward scan are implemented, then scan flexibility is improved, but voltage level instability occurs causing display quality degradation

Engineering Contradiction:

Improvescan direction controlVSAvoidvoltage level

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The pull-down module performs preliminary action by actively pulling the output node voltage to a predetermined low level before the scan operation begins. This pre-positioning of voltage levels ensures stability when switching between forward and backward scan modes, preventing display quality degradation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reset module provides feedback control by monitoring the voltage levels at various nodes and actively resetting them to predetermined levels when abnormal conditions are detected. This feedback mechanism maintains voltage level stability during bidirectional scanning operations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10586604B1Shift register, gate driving circuit, display device, and driving method thereof

Publication Date: 2020.03.10 SHANGHAI AVIC OPTO ELECTRONICS CO LTD

AI summary

A shift register includes a forward/backward scan-control module, configured to transmit a signal of a forward-scan-signal terminal or a signal of a backward-scan-signal terminal to a first node; an interlock module, configured to transmit a signal of a first voltage terminal to a second node, and transmit a signal of a second voltage terminal to the first node; a pull-down module, configured to transmit the signal of the first voltage terminal to a gate-signal output terminal; an output module, configured to transmit a signal of a second clock-signal terminal to the gate-signal output terminal; and a reset module, configured to transmit the signal of the second voltage terminal to the first node, and transmit the signal of the first voltage terminal to the gate-signal output terminal. The disclosed shift register can prevent leakage of the first node, and thus improve the quality and the performance of the shift register.