OLED Pixel Circuit Pre-Charge Control for Uniform Display
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Solution Overview
Problem
Display devices with organic light-emitting elements face issues with display defects such as unevenness due to pre-charge voltages generated by source-driver ICs, which affect image quality.
Innovation Solution
A display device with a specific transistor configuration and control signal management system that includes multiple transistors and capacitive elements to manage and supply various voltages and signals to pixels, ensuring precise control and minimizing display defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a source-driver IC supplies pre-charge voltage to pixels, then pixel initialization is improved, but display unevenness and defects occur due to voltage fluctuations
Solution Approach 1:
The pixel circuit is divided into multiple independent transistor components (first through sixth transistors) that separately control different voltage supply paths. This segmentation allows precise individual control of pre-charge voltage, initialization voltage, and data voltage supplies, eliminating the display unevenness caused by unified voltage control while maintaining proper pixel initialization.
Solution Approach 2:
The invention changes the voltage parameters supplied to different nodes of the pixel circuit at different times. Pre-charge voltage is applied to the first node before data writing, initialization voltage is applied to the third node independently, and data voltage is supplied afterward. This temporal and parametric separation ensures uniform display without defects while maintaining proper pixel state management.
2Manufacturing precision
If multiple voltages are supplied to pixels for precise control, then display quality is improved, but circuit complexity increases
Solution Approach 1:
The capacitive element in the pixel circuit serves multiple functions: it stores pre-charge voltage for initializing the first node, maintains data voltage during the display period, and works协同 with multiple transistors to enable precise voltage control. This multi-functionality reduces the need for separate circuit components for each function, thereby managing complexity while achieving high display quality.
Solution Approach 2:
The circuit performs preliminary actions by supplying pre-charge voltage to the first node and initialization voltage to the third node before data voltage is written to the pixel. This preliminary voltage establishment ensures that the pixel is properly initialized and ready to receive data, improving display quality without requiring complex real-time control mechanisms.
Data Source
AI summary
A display device includes a first transistor connected between an image data signal line and a first node, switching of the first transistor controlled by a first control signal, a third transistor connected between the first node and a second node, switching of the third transistor controlled by a second control signal, a second transistor connected to the second node and connected between a power line and the third node, a fourth transistor connected between a reference voltage power line and the second node, switching of the fourth transistor controlled by the second control signal, a fifth transistor connected between an initialization voltage power line and the third node, switching of the fifth transistor controlled by the third control signal, and a sixth transistor electrically connected between a pre-charge voltage power line and the first node, and switching of the sixth transistor controlled by the fourth control signal.