Pixel Driving Circuit Voltage Stability OLED Display
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Solution Overview
Problem
Current organic light emitting display technologies face instability in voltage due to current leakage from transistors connected to the gate of the driving transistor, leading to flicker issues in the display.
Innovation Solution
A pixel driving circuit with a connection control module and initializing module that disconnects during the light emitting phase to prevent current leakage, ensuring stable voltage transmission to the Organic Light Emitting Diode (OLED).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transistors are connected to the gate of the driving transistor to control light emission, then the light emitting display can be controlled, but current leakage occurs from these transistors causing voltage instability and flicker
Solution Approach 1:
The circuit is divided into functionally independent modules: a light emission driving module (first transistor) and a connection control module (second transistor). The connection control module acts as a switch that isolates the initializing module from the driving transistor gate during light emission, preventing current leakage while maintaining control capability during initialization phases.
Solution Approach 2:
The initializing module performs preliminary voltage initialization of the driving transistor gate before the light emission phase. By establishing the correct voltage state in advance through the connection control module, the system ensures stable operation during light emission without requiring continuous connection that would cause leakage.
2Reliability
If the initializing module remains connected to the driving transistor gate, then voltage initialization can be performed, but current leakage prevents complete transistor turn-off and causes voltage instability
Solution Approach 1:
The connection control module enables periodic connection and disconnection based on operational phases. During initialization phases, the module is connected to perform voltage initialization. During light emission phases, it disconnects to prevent current leakage. This periodic switching resolves the contradiction between maintaining initialization capability and preventing energy loss.
Solution Approach 2:
The connection control module extracts the switching function from the initializing module itself. By separating the initialization function from the continuous connection requirement, the system can initialize the driving transistor gate voltage when needed while completely disconnecting during light emission to eliminate current leakage paths.
3Reliability
If a connection control module is added to disconnect during light emission, then current leakage is prevented and voltage stability is improved, but device complexity increases
Solution Approach 1:
The connection control module serves multiple functions: it acts as a switch to prevent current leakage during light emission, enables voltage initialization during initialization phases, and provides a controlled connection path. By consolidating these functions into a single module with dual gates, the design achieves voltage stability without proportionally increasing complexity.
Solution Approach 2:
The initializing module and connection control module are merged into an integrated structure where the second transistor's source/drain terminals directly connect to the first transistor's gate. This combining reduces the number of separate components and interconnections needed, achieving current leakage prevention with minimal additional circuit complexity.
Data Source
AI summary
Provided is a pixel driving circuit, a driving method and an organic light emitting display panel. The pixel driving circuit includes: a light emitting display module, including an OLED; a light emission driving module, including a first control terminal, a first input terminal and a first output terminal, the first output terminal being electrically connected to the light emitting display module; a connection control module, including a second input terminal and a second output terminal, the second output terminal being connected to the first control terminal of the light emission driving module; and a first initializing module, including a third input terminal and a third output terminal, the third input terminal being connected to a first reference voltage signal line and the third output terminal being connected to the second input terminal.