Pixel Circuit Mobility Correction via Switching Transistor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As display devices increase in size or aperture ratio, the capacitance of organic EL elements increases, leading to longer times required for mobility correction, which is a technical challenge in existing display devices.
Innovation Solution
A pixel circuit configuration that includes a driver transistor, a write transistor, a first light-emitting element, a switching transistor, and a second light-emitting element, where the switching transistor turns ON after a write operation and turns OFF before mobility correction begins, reducing the capacitance and speeding up the mobility correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size or aperture ratio of the display device is increased, then the surface area of organic EL elements is increased, but the time required for mobility correction is increased
Solution Approach 1:
The pixel circuit is divided into two separate circuits: a first pixel circuit for display operation and a second pixel circuit for mobility correction. The switching transistor connects the driver transistor to either the first or second light emitting element based on the operational phase, enabling independent execution of display and correction functions without interference from capacitance of the non-active element
Solution Approach 2:
The switching transistor dynamically changes the connection configuration of the driver transistor between different light emitting elements based on the operational phase (display phase vs. correction phase). This dynamic reconfiguration allows the system to adapt the circuit topology to optimize performance for each specific function, reducing mobility correction time while maintaining display quality
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 configuration effectively reduces the time required for mobility correction, improving the speed and efficiency of the process while maintaining image quality by minimizing discrepancies in emission start times due to threshold voltage variations.
Implementation Method 1
organic EL elements are electro-optic elements that make use of the phenomenon that light is emitted when an electrical field is applied to an organic thin film
Data Source
AI summary
A pixel circuit includes: a driver transistor that supplies a current dependent on a voltage supplied via a signal line; a write transistor connected between the signal line and a gate electrode of the driver transistor; a first organic EL element connected to one electrode of the driver transistor, the one electrode being one of a drain electrode and a source electrode of the driver transistor; a switching transistor connected to the one electrode of the driver transistor; and a second organic EL element connected to the one electrode of the driver transistor via the switching transistor. The pixel circuit performs mobility correction that corrects a mobility of the driver transistor. The switching transistor turns ON after a write operation that writes the voltage supplied via the signal line and turns OFF before an operation that performs the mobility correction of the driver transistor begins.