Pixel Circuit Coupling Module for Low Gray Scale Brightness Uniformity

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Solution Overview

Problem

Existing pixel circuits suffer from poor brightness uniformity at low gray scales due to incomplete threshold voltage compensation and subthreshold swing fluctuations, leading to inconsistent drive currents across different pixel circuits.

Innovation Solution

A pixel circuit design incorporating a drive module, data write module, first and second compensation modules, storage module, and coupling module, where the coupling module adjusts the voltage of the control terminal of the drive module by coupling a jump voltage to the second compensation module or its internal node, ensuring consistent drive currents across different pixel circuits under the same gray scale voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If threshold voltage compensation is performed using conventional pixel circuits, then some threshold voltage compensation is achieved, but the compensation is incomplete and brightness uniformity at low gray scale remains poor

Engineering Contradiction:

Improvethreshold voltage compensation completenessVSAvoidbrightness uniformity at low gray scale

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The compensation function is divided into two separate modules: a first compensation module for threshold voltage compensation and a second compensation module for fine-tuning the control terminal voltage. This segmentation allows each module to specialize in a specific compensation task, achieving both complete threshold compensation and precise brightness control at low gray scales.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second compensation module acts as an intermediary between the data write module and the drive module, providing fine-tuning adjustment of the control terminal voltage. This intermediary mechanism enables precise control of drive current to achieve uniform brightness at low gray scales while maintaining the threshold compensation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the pixel circuit structure is simplified to reduce complexity, then ease of manufacture improves, but the ability to achieve complete threshold compensation and fine voltage adjustment deteriorates

Engineering Contradiction:

Improvepixel circuit structure simplicityVSAvoidthreshold compensation and voltage adjustment capability

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The second compensation module is designed with multi-functionality, serving both as a fine-tuning adjustment mechanism for the control terminal voltage and as a means to compensate for subthreshold swing fluctuations. This universal design achieves precise voltage control without significantly increasing circuit complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention introduces a jump voltage parameter that can be coupled to the second compensation module to achieve fine adjustment of the control terminal voltage. By changing voltage parameters rather than adding complex circuit structures, the invention maintains manufacturing simplicity while achieving precise compensation.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional compensation methods are used, then the basic threshold compensation function is provided, but drive current consistency across different pixel circuits under the same gray scale voltage cannot be ensured

Engineering Contradiction:

Improvedrive current consistencyVSAvoidcompensation circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The second compensation module provides dynamic fine-tuning capability that adapts to variations in drive module characteristics. By dynamically adjusting the control terminal voltage based on actual pixel circuit performance, the system ensures drive current consistency across different pixels while maintaining a relatively simple circuit structure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The coupling of jump voltage to the second compensation module creates a feedback mechanism that compensates for variations in drive module threshold voltages and subthreshold swing. This feedback approach ensures consistent drive current across different pixel circuits without requiring complex pre-characterization or matching.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12170064B2Pixel circuit and driving method therefor, and display panel

Publication Date: 2024.12.17 SUZHOU GOVISIONOX INNOVATION TECHNOLOGY CO LTD

AI summary

A pixel circuit, a driving method for a pixel circuit, and a display panel. The pixel circuit includes a drive module, a data write module, a first compensation module, a second compensation module, a light-emitting module, a storage module and a coupling module. The data write module is configured to write a voltage related to a data voltage to a control terminal of the drive module. The drive module is configured to provide a drive signal to the light-emitting module according to the voltage of the control terminal to drive the light-emitting module to emit light. A first terminal of the second compensation module is connected to the control terminal of the drive module, a second terminal of the second compensation module is connected to a first terminal of the first compensation module.