OLED Pixel Circuit Gating and Compensation for Stable Driving Current
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Solution Overview
Problem
The driving current in OLED pixel circuits is easily disturbed by external DC power supply, leading to reduced display effectiveness.
Innovation Solution
A pixel circuit design incorporating a driving unit, first and second light-emitting control units, a threshold compensation unit, and storage units, which are configured to control the coupling and decoupling of terminals and power lines to stabilize the driving current, and a gating unit to manage reference signal lines, thereby isolating the circuit from external DC power fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pixel circuit is directly connected to external DC power supply, then the circuit can operate simply, but the driving current is easily disturbed by external DC power fluctuations
Solution Approach 1:
The patent introduces a first light-emitting control unit as an intermediary component between the external DC power supply and the driving unit. This control unit selectively couples or decouples the first power line from the first terminal of the driving unit, acting as a mediator that isolates the driving current from external DC power fluctuations while maintaining operational simplicity
Solution Approach 2:
The patent employs dynamic coupling and decoupling mechanisms through the first and second light-emitting control units. These control units can switch the connection state of power lines and terminals based on operational requirements, transforming the static circuit connection into a dynamic system that adapts to different working phases (e.g., threshold compensation phase vs. light-emitting phase)
2Reliability
If multiple control units are added to stabilize driving current, then current stability improves, but circuit complexity increases
Solution Approach 1:
The patent designs the first light-emitting control unit and second light-emitting control unit to perform multiple functions. Each control unit can couple or decouple different terminals and power lines based on operational phases, making them multi-functional components that reduce the need for separate dedicated components for each function
Solution Approach 2:
The patent combines the threshold compensation function and light-emitting control function into an integrated circuit structure. The threshold compensation unit and light-emitting control units share common components and control signals, merging multiple functions into a unified design that reduces overall circuit complexity
Data Source
AI summary
A pixel circuit includes a driving unit including first, second, and third terminals, the second terminal being coupled to a first electrode of a light-emitting element; a first light-emitting control unit coupled between a first power line and the first terminal, configured to couple/decouple the first power line to/from the first terminal; a second light-emitting control unit coupled between the second terminal and the first electrode, configured to couple/decouple the second terminal to/from the first electrode; a threshold compensation unit coupled between the first terminal and the first electrode, configured to couple/decouple the first terminal to/from the first electrode; a first storage unit and a second storage unit coupled at a first node and in series between the third terminal and the first; a gating unit coupled between a first reference signal line and the first node, configured to couple/decouple the first reference signal line to/from the first node.