OLED Pixel Circuit Using Oxide Semiconductors to Reduce Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting devices face challenges in reducing power consumption and voltage fluctuations due to leakage currents, particularly when using low temperature polycrystalline silicon (LTPS) transistors, which require separate driving units and complicate the driving circuit structure.
Innovation Solution
The implementation of a pixel structure that includes oxide semiconductor thin film transistors instead of LTPS transistors, reducing leakage currents and allowing for a simplified driving unit by eliminating the need for separate driving units for oxide semiconductor and LTPS transistors, with a configuration that includes multiple transistors and a storage capacitor to control current flow and emission in the organic light emitting diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If LTPS transistors are used in organic light emitting devices, then the devices can achieve fast response speed, but the leakage currents increase and power consumption increases
Solution Approach 1:
The patent changes the material parameter of the transistor from LTPS (low temperature polycrystalline silicon) to oxide semiconductor, which fundamentally alters the electrical characteristics including leakage current properties. This material substitution reduces leakage current by several orders of magnitude while maintaining fast response characteristics, thereby resolving the contradiction between speed and power consumption.
2Reliability
If separate driving units are used for oxide semiconductor and LTPS transistors, then the transistors can be driven appropriately, but the driving circuit structure becomes complicated
Solution Approach 1:
The patent merges the driving units for oxide semiconductor transistors and LTPS transistors into a single unified driving circuit. By using the same transistor structure and driving methodology for both types, the patent eliminates the need for separate driving units, thereby simplifying the overall circuit structure while maintaining reliable control over different transistor types.
Solution Approach 2:
The patent designs a universal transistor structure that can function as both an oxide semiconductor transistor and an LTPS transistor depending on the material used. This universal design allows a single driving unit to control both types of transistors appropriately, achieving multi-functionality in the driving circuit and eliminating structural complexity.
3Loss of energy
If oxide semiconductor thin film transistors are used, then leakage currents are reduced and power consumption decreases, but the transistor structure and driving requirements differ from LTPS transistors
Solution Approach 1:
The patent changes the semiconductor material parameter from LTPS to oxide semiconductor, which inherently reduces leakage current and power consumption. The patent then adapts the transistor structure and driving parameters to match the oxide semiconductor characteristics, achieving low power consumption while maintaining structural consistency with LTPS-based designs.
4Productivity
If high scanning rate is used, then the display performance is improved, but power consumption increases due to leakage currents
Solution Approach 1:
The patent changes the transistor material to oxide semiconductor, which fundamentally alters the leakage current characteristics. This material parameter change enables the display to operate at high scanning rates without the proportional increase in power consumption that would otherwise occur, as the oxide semiconductor maintains low leakage current even under high-speed operation conditions.
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 solution enables organic light emitting devices to operate at a low scanning rate with reduced power consumption and voltage fluctuations, achieving high brightness while simplifying the driving unit structure and eliminating the need for separate driving units for different transistor types.
Implementation Method 1
an organic light emitting diode (OLED) generating light by the recombination of electrons and holes
Data Source
AI summary
A pixel includes an organic light emitting diode (OLED), a first transistor connected to a driver and a first node, having a gate connected to a control line, a second transistor between to the first node and a second node, having a gate connected to a third node, a third transistor connected to an anode of the OLED, having a gate connected to the control line, a fourth transistor between the first node and a data line, having a gate connected to a scan line, a fifth transistor between the second and third nodes, having a gate connected to the scan line, a sixth transistor between an initializing line and the anode, having a gate connected to the scan line, a seventh transistor between the initializing line and the third node, having a gate connected to another scan line, and a storage capacitor between the driver and the third node.