Pixel Drive Circuit With Metal-Oxide Compensation for Flicker

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Solution Overview

Problem

LTPS transistors in display panels suffer from low frequency flickering under low gray scale display, reducing display quality.

Innovation Solution

A pixel drive circuit with a threshold compensation transistor made of metal oxide semiconductor, a storage capacitor design, and a specific driving method to manage node voltages, reducing leakage currents and enhancing voltage hold capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If LTPS transistors are used in display panels, then driving ability and electron mobility are improved, but low frequency flickering occurs under low gray scale display

Engineering Contradiction:

Improvedriving abilityVSAvoiddisplay quality

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent changes the material parameter of the threshold compensation transistor from LTPS to metal oxide semiconductor, which has different electrical characteristics including lower leakage current. This material parameter change resolves the flickering issue while maintaining the driving capability provided by LTPS transistors in other circuit elements.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If refresh frequency is increased to reduce flickering, then display quality is improved, but power consumption increases

Engineering Contradiction:

Improvedisplay qualityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent converts the typically harmful leakage current into a beneficial effect by using metal oxide semiconductor's naturally low leakage current特性 to maintain stable node voltages. This eliminates the need for high refresh frequencies to combat flickering, thereby reducing power consumption while improving display quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If voltage holding capability is improved to reduce flickering, then display quality is improved, but circuit complexity increases

Engineering Contradiction:

Improvevoltage holding capabilityVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by selectively using metal oxide semiconductor material only for the threshold compensation transistor where low leakage current is most critical for voltage holding. Other transistors in the circuit can use simpler LTPS material, thus achieving improved voltage holding capability without uniformly increasing circuit complexity throughout the entire display panel.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12451062B2Pixel drive circuit and driving method thereof, and display panel

Publication Date: 2025.10.21 BEIJING BOE TECH DEV CO LTD

AI summary

The source, drain and gate of the drive transistor of the pixel drive circuit are respectively connected to the first node, the second node and the third node. The storage capacitor is connected to the third node. The first control unit is used for enabling a path between the second node and the fourth node in response to the first control signal. The second control unit is used for outputting the first power supply voltage to the first node in response to the light-emitting signal. The threshold compensation transistor is used for enabling a path between the second node and the third node in response to the second control signal. The material of the active region is a metal oxide semiconductor.