LTPS and Oxide TFT Pixel Circuit for OLED Leakage Control
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Solution Overview
Problem
Organic light emitting displays face issues with current leakage from driving transistors, leading to voltage instability and adverse effects on brightness due to low voltage and frequency driving methods.
Innovation Solution
The use of n-type Low Temperature Poly-Silicon (LTPS) and oxide semiconductor thin film transistors in a pixel circuit, including specific transistor configurations and a storage capacitor, to control current flow and maintain voltage stability, along with a stage circuit buffer design using parallel transistors for improved driving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If low voltage and low frequency driving methods are used to reduce power consumption, then power consumption is reduced, but current leakage increases and voltage stability deteriorates
Solution Approach 1:
The patent changes the material parameter of the transistor from conventional semiconductor to oxide semiconductor, which fundamentally alters the electrical characteristics to achieve ultra-low off-state current. This material parameter change enables the system to maintain voltage stability even under low voltage and low frequency driving conditions, thus resolving the contradiction between power consumption reduction and voltage stability.
2Use of energy by stationary object
If low voltage driving is used to reduce power consumption, then power consumption is reduced, but current leakage from driving transistor increases
Solution Approach 1:
The patent changes the material parameter of the driving transistor to oxide semiconductor, which fundamentally alters the electrical characteristics to achieve ultra-low off-state current. This material parameter change enables the system to maintain voltage stability even under low voltage and low frequency driving conditions, thus resolving the contradiction between power consumption reduction and voltage stability.
3Device complexity
If conventional transistor materials are used to simplify device structure, then device complexity is reduced, but driving speed and performance are insufficient
Solution Approach 1:
The patent employs a composite transistor structure combining oxide semiconductor channel layer with specific gate electrode configurations. This composite material approach achieves both low power consumption and high driving speed, resolving the contradiction between device simplicity and performance.
Data Source
AI summary
A pixel includes a plurality of transistors and an organic light emitting diode, in which the transistors include a first transistor to control an amount of current flowing to the organic light emitting diode and additional transistors are connected to the first transistor or the organic light emitting diode, the first transistor is a Low Temperature Poly-Silicon (LTPS) thin film transistor, and one or more of the other transistors are oxide semiconductor transistors.