Pixel Circuit Integration to Reduce TFT Nodes in High-PPI OLED Displays
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Solution Overview
Problem
High PPI displays face challenges in achieving compact circuit layouts due to the presence of multiple transistor nodes, which increase complexity and limit pixel density, making it difficult to realize high pixel density in OLED devices.
Innovation Solution
A pixel circuit design with reduced transistors, including a data writing element, energy storage elements, a drive element, a light-emitting control transistor, a compensation element, and reset elements, optimized for efficient integration and operation, such as PMOS transistors and capacitors, to facilitate high PPI displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple transistor nodes are used in the drive circuit, then the circuit can perform data writing, reset, and compensation functions, but the circuit complexity and size increase, limiting pixel density
Solution Approach 1:
The patent combines the data writing element and reset element into a single integrated circuit structure. The data writing element serves dual purposes: writing data during the data writing phase and resetting the storage node during the reset phase. This merging eliminates the need for separate dedicated reset transistor, reducing circuit complexity while maintaining both data writing and reset functionalities.
Solution Approach 2:
The data writing element is designed as a universal component that performs multiple functions: it acts as a data writing transistor during the data writing phase, and as a reset transistor during the reset phase. This multi-functionality reduces the total number of transistors needed in the circuit while maintaining complete operational capability.
2Adaptability or versatility
If multiple transistor nodes are connected to the energy storage circuit, then data writing and reset functions are achieved, but the circuit size increases, reducing pixel density
Solution Approach 1:
The patent merges the data writing element and reset element into a single integrated structure sharing common connections to the energy storage circuit. This consolidation reduces the number of separate transistor nodes and interconnections, thereby reducing the overall circuit area occupied by the drive circuit.
Solution Approach 2:
The patent extracts and eliminates the separate reset transistor from the traditional multi-transistor configuration. By taking out the dedicated reset transistor and integrating its functionality into the data writing element, the circuit area is reduced while maintaining the reset function.
3Ease of operation
If traditional OLED drive circuit is used with data writing circuit, reset circuit, and compensation circuit in off state, then circuit operation is simplified, but high PPI cannot be realized due to large number of TFT nodes
Solution Approach 1:
The patent combines multiple circuit functions into fewer transistor nodes. The data writing element integrates data writing and reset functions, reducing the total number of TFT nodes while maintaining operational simplicity through unified control signals.
Solution Approach 2:
The data writing element is designed as a universal transistor that can perform both data writing and reset operations based on timing control. This multi-functionality reduces the number of dedicated TFT nodes while keeping the operation simple through phase-based control.
Data Source
AI summary
The present disclosure provides a pixel circuit and driving method thereof. The pixel circuit includes: a data writing element configured for controlling an input of a data signal; a first energy storage element configured for storing the data signal output from the data writing element; a second energy storage element configured for storing the data signal together with the first energy storage element; a light-emitting element configured for light-emitting display; a drive element, an output end of which is configured for providing a light-emitting current to the light-emitting element; a light-emitting control transistor configured for controlling a conduction between the drive element and the light-emitting element; a compensation element; and a first reset element.