Display Pixel Double-Gate Circuit for Low-Power Threshold Compensation

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Solution Overview

Problem

Display devices face issues with improper threshold voltage levels in driving transistors leading to luminance errors and increased power consumption, along with horizontal crosstalk reducing image quality.

Innovation Solution

A pixel design incorporating a first transistor with a double gate structure, a first capacitor for data voltage storage, and a second capacitor for threshold voltage storage in a diode connection manner, along with specific transistor operations during compensation and non-compensation frame periods to optimize threshold voltage compensation and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a compensation operation is performed to compensate the threshold voltage of the driving transistor, then luminance error is reduced, but power consumption increases excessively

Engineering Contradiction:
Improveluminance accuracyVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs threshold voltage compensation in advance during a dedicated compensation period before the actual display operation. The compensation transistor stores the threshold voltage value in a capacitor, so that subsequent display operations can proceed without continuous compensation, reducing overall power consumption while maintaining luminance accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements compensation operations periodically rather than continuously. The compensation is performed in specific frame periods (compensation frames) while other frames operate in normal display mode, creating a periodic pattern that reduces average power consumption while maintaining image quality through regular threshold voltage updates.

Inventive Principle:
Principle #19Periodic action

2Ease of manufacture

If the pixel configuration is simplified, then manufacturing is easier, but horizontal crosstalk occurs reducing image quality

Engineering Contradiction:
Improvepixel fabricationVSAvoidimage quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a compensation transistor that segments the pixel circuit into distinct functional regions: a compensation region for threshold voltage measurement and storage, and a display region for normal operation. This segmentation isolates the compensation function from the display function, preventing horizontal crosstalk while maintaining manufacturing feasibility through modular circuit design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compensation transistor acts as an intermediary element between the data line and the storage capacitor. It mediates the threshold voltage compensation process by temporarily connecting these elements during compensation frames, enabling accurate threshold voltage storage without creating direct pathways that would cause horizontal crosstalk during normal display operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If the driving transistor threshold voltage is improper, then power consumption is reduced, but luminance output is insufficient

Engineering Contradiction:
Improvepower consumptionVSAvoidluminance output
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent implements a feedback mechanism where the compensation transistor measures the actual threshold voltage of the driving transistor and stores this value for compensation. This feedback loop allows the system to automatically adjust for threshold voltage variations, ensuring optimal luminance output while managing power consumption through precise threshold voltage control rather than excessive compensation operations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4589582A1Pixel of a display device, and display device
Publication Date: 2025.07.23 SAMSUNG DISPLAY CO LTD
  • EP4589582A1 patent drawingFigure 1
  • EP4589582A1 patent drawingFigure 2
  • EP4589582A1 patent drawingFigure 3

AI summary

A pixel includes a first transistor including a first and second gates, a first capacitor connected between a first node and a third node, a second capacitor connected between a fourth node and the third node, a second transistor receiving a first scan signal and connected between a data line and the first node, a third transistor receiving a second scan signal and connected between a reference voltage line and the first node, a fourth transistor receiving a third scan signal and connected between an initialization line and the third node, a fifth transistor receiving an emission signal and connected between a first power line and the second node, a sixth transistor receiving the second scan signal and connected between the fourth node and the second node, and a light emitting element connected between the third node and a second power line.