Shift Register Impedance Transistor Voltage Stability

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Solution Overview

Problem

The operation state of the shift register in conventional gate driving circuits is unstable, leading to abnormal output and display issues in pixel units.

Innovation Solution

The proposed solution involves a shift register design that includes a first transistor coupled to a first clock signal line, a second transistor coupled to the first node, a third transistor coupled to the first power terminal, and an impedance transistor between the second node and the third node to stabilize the voltage levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an impedance transistor is added to stabilize voltage levels, then the stability of the shift register operation is improved, but the device complexity increases

Engineering Contradiction:

Improvestability of shift register operationVSAvoidnumber of transistors in shift register

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

An impedance transistor is introduced as an intermediary component between existing nodes in the shift register circuit. This impedance transistor acts as a mediator to regulate and stabilize voltage levels at the third node, preventing abnormal pull-up effects without requiring fundamental changes to the overall circuit architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The impedance transistor dynamically adjusts electrical parameters (voltage levels) at the third node by controlling its resistance characteristics. By changing the impedance state of this transistor based on circuit conditions, the voltage stability is improved while maintaining compatibility with the existing circuit operation.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the shift register circuit is simplified to reduce complexity, then the ease of manufacture is improved, but the voltage stability at the third node deteriorates

Engineering Contradiction:

Improvesimplicity of shift register circuitVSAvoidvoltage stability at third node

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The impedance transistor serves as a minimal additional component that mediates the voltage instability issue without requiring complete circuit redesign. It is inserted between existing nodes to provide the necessary voltage regulation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution applies local stabilization only at the specific third node where voltage instability occurs, rather than redesigning the entire shift register circuit. The impedance transistor is placed specifically at the location where voltage control is needed, leaving other parts of the circuit unchanged.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12293719B2Shift register, driving circuit and display substrate

Publication Date: 2025.05.06 CHENGDU BOE OPTOELECTRONICS TECH CO LTD

AI summary

The present disclosure provides a shift register including a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first capacitor and an impedance transistor; the second transistor has a first electrode coupled to a second node; the third transistor has a first electrode coupled to a first power terminal and a second electrode coupled to the second node; the fifth transistor has a control electrode coupled to a third node; and the impedance transistor has a control electrode coupled to the first power terminal, a first electrode coupled to the second node, and a second electrode coupled to the third node.