Direct-Gate Pixel Circuit for High-PPI Threshold Compensation

Solution Overview

Problem

Existing display devices face challenges in achieving high-resolution displays due to the complex structure of pixels with multiple transistors and capacitors, which limits the area reduction and implementation of high pixel density.

Innovation Solution

A pixel design that includes a transistor with a gate directly connected to a node, a capacitor with direct connections to data power, and a light emitting diode, eliminating the need for a separate switching transistor, and utilizing a back gate voltage for threshold voltage compensation, allowing for a simplified pixel structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pixel includes multiple transistors and capacitors for data writing, driving, compensation, and initialization, then the display device can achieve threshold voltage compensation and proper light emitting control, but the pixel area increases and high-resolution display is limited

Engineering Contradiction:

Improvethreshold voltage compensationVSAvoidpixel area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts and eliminates the switching transistor from the pixel structure. By using the driving transistor's gate as the first node directly connected to the data line, the switching function is integrated into the driving transistor's operation rather than requiring a separate switching transistor, thereby reducing pixel area while maintaining compensation functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the switching function with the driving transistor by directly connecting the gate of the driving transistor to the data line. This integration eliminates the need for a separate switching transistor and reduces the number of components in the pixel circuit, achieving area reduction while preserving both switching and driving functions

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If a pixel includes multiple transistors and capacitors for data writing, driving, compensation, and initialization, then the display device can achieve proper light emitting control, but the pixel area increases and high-resolution display is limited

Engineering Contradiction:

Improvelight emitting controlVSAvoidpixel area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts and eliminates the switching transistor from the pixel structure. By using the driving transistor's gate as the first node directly connected to the data line, the switching function is integrated into the driving transistor's operation rather than requiring a separate switching transistor, thereby reducing pixel area while maintaining control functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The driving transistor is made multi-functional by directly connecting its gate to the data line, allowing it to perform both switching and driving functions. This universal approach eliminates the need for separate switching and driving transistors, reducing pixel area while maintaining proper light emitting control

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a separate switching transistor is used for data writing, then the pixel structure can achieve proper data input control, but the device complexity increases

Engineering Contradiction:

Improvedata input controlVSAvoidpixel structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the switching transistor from the pixel structure. By using the driving transistor's gate as the first node directly connected to the data line, the switching function is integrated into the driving transistor's operation rather than requiring a separate switching transistor, thereby reducing device complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the switching function with the driving transistor by directly connecting the gate of the driving transistor to the data line. This integration eliminates the need for a separate switching transistor and reduces the number of components in the pixel circuit, achieving simplicity while preserving switching control functionality

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design reduces the pixel area, enabling high-resolution displays with improved display quality and higher pixels per inch (PPI) without the need for additional transistors, thereby enhancing display performance.

Implementation Method 1

a light emitting diode including a first diode terminal connected to the second node, and a second diode terminal connected to a second power

Methodology Applied

Scientific EffectLight emitting diode electroluminescence: Light Emitting Diode

Data Source

PatentUS12562118B2Pixel with gate of driving transistor directly connected to drain and display device including the same

Publication Date: 2026.02.24 SAMSUNG DISPLAY CO LTD

AI summary

A pixel according to one or more embodiments of the present disclosure may include a transistor including a gate terminal connected to a first node, a first terminal connected to a first power, and a second terminal connected to a second node having a same potential as the first node, a capacitor including a first capacitor terminal connected to a data power, and a second capacitor terminal connected to the first node, and a light emitting diode including a first diode terminal connected to the second node, and a second diode terminal connected to a second power.