OLED Driving TFT Channel Doping for Lower Saturation Voltage

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Solution Overview

Problem

Current OLED display panels face high power consumption due to large saturation voltages of driving thin film transistors, which generate excessive heat and increase thermal consumption.

Innovation Solution

The display panel design includes a driving thin film transistor with a channel region having varying doping ion concentrations, specifically with a lower concentration near the drain region, to reduce the saturation voltage and thereby decrease power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the saturation voltage of the driving thin film transistor is increased to ensure stability of output current, then the reliability of current driving is improved, but the thermal consumption and power consumption of the transistor increases

Engineering Contradiction:
Improvestability of output currentVSAvoidthermal consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The channel region is divided into two parts with different doping ion concentrations: a first part closer to the source region with higher doping concentration and a second part closer to the drain region with lower doping concentration. This local differentiation allows the transistor to maintain reliable current driving while reducing overall saturation voltage and thermal consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The doping ion concentration parameter is changed along the channel length, creating a gradient from higher concentration near the source to lower concentration near the drain. This parameter variation optimizes the balance between current stability and power consumption by reducing the saturation voltage requirement.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the drain-source voltage is increased to be greater than saturation voltage for stable operation, then the reliability of light emitting element driving is improved, but the power consumption of the display panel increases

Engineering Contradiction:
Improvestability of light emitting element drivingVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

By creating local quality differences in the channel region through varied doping concentrations, the transistor achieves more efficient voltage utilization. The lower doping region near the drain reduces the voltage required to achieve saturation, thereby reducing power consumption while maintaining reliable light emitting element driving.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The doping concentration parameter is optimized to reduce the saturation voltage threshold. This allows the display panel to operate at lower drain-source voltages while maintaining stable light emitting element performance, thus reducing overall power consumption.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4641640A1Display panel and display device
Publication Date: 2025.10.29 WUHAN CHINA STAR OPTOELECTRONICS SEMICONDUCTOR DISPLAY TECHNOLOGY CO LTD
  • EP4641640A1 patent drawingFigure 1~2
  • EP4641640A1 patent drawingFigure 3~4
  • EP4641640A1 patent drawingFigure 5~7

AI summary

A display panel and a display device. The display panel includes a power supply high-voltage signal line, a driving thin film transistor, and a light emitting element. The driving thin film transistor comprises an active layer. The active layer includes a source region, a drain region, and a channel region. The source region is connected to the power supply high-voltage signal line. The drain region is connected to the light emitting element. A part of the channel region close to the drain region has a lower majority carrier concentration than a part of the channel region close to the source region.