OLED Pixel Circuit Vertical Stacking for High PPI
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Solution Overview
Problem
Conventional OLED displays with laterally arranged sub-pixels of different colors occupy a large space on the panel, hindering the achievement of high pixel density (PPI).
Innovation Solution
A pixel circuit is designed with a driving sub-circuit and a light-emitting control sub-circuit that allows for time-sharing driving of three light-emitting elements (red, green, and blue) in different periods, optimizing the use of space by stacking them vertically and using a control circuit to manage voltage and power signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sub-pixels of different colors are arranged laterally on the panel, then each sub-pixel can be independently controlled, but the space occupied by each pixel unit increases
Solution Approach 1:
The patent transitions from lateral (2D) arrangement of sub-pixels to vertical (3D) stacking. Multiple light-emitting elements (first, second, and third light-emitting elements) are arranged in different vertical layers, allowing independent control of each sub-pixel while significantly reducing the horizontal space occupied by each pixel unit.
Solution Approach 2:
The pixel unit is segmented into multiple independently controllable light-emitting elements stacked vertically. Each light-emitting element corresponds to a different color sub-pixel (red, green, blue), and the control circuit separately manages each element through different time periods, enabling independent control while compacting the structure.
2Area of stationary object
If multiple light-emitting elements are stacked vertically in a pixel unit, then space is reduced and pixel density increases, but control complexity of the circuit increases
Solution Approach 1:
The control circuit uses periodic time-division multiplexing to control multiple light-emitting elements sequentially. Different time periods are allocated to different light-emitting elements (first time period for first element, second time period for second element, third time period for third element), allowing simple switching control without complex simultaneous drive circuits.
Solution Approach 2:
The control circuit is designed with multi-functional transistors and nodes that serve multiple purposes. For example, the same control circuit nodes and power signal terminals are reused across different light-emitting elements at different time periods, reducing the need for separate dedicated control paths for each element.
3Area of stationary object
If time-sharing driving is used for different light-emitting elements, then space efficiency improves, but interference between elements during light emission may occur
Solution Approach 1:
The patent implements strict time-division multiplexing where each light-emitting element is activated in its designated time period only. The first light-emitting element emits light in the first time period, the second in the second time period, and the third in the third time period, ensuring no temporal overlap and eliminating light emission interference between elements.
Solution Approach 2:
The control circuit acts as an intermediary that manages and isolates the operation of different light-emitting elements. Through controlled switching of transistors and timing signals, the control circuit prevents simultaneous activation of multiple elements, thereby avoiding interference while maintaining efficient space utilization.
Data Source
AI summary
The present disclosure provides a pixel circuit and a method for driving the same, and a display panel. The pixel circuit includes a driving sub-circuit and a light-emitting control sub-circuit. The driving sub-circuit is configured to transmit a first power voltage at a first power signal terminal to a second node. The light-emitting control sub-circuit is configured to: transmit a voltage at the second node and a second power voltage at the second power signal terminal to the first electrode of the first light-emitting element and the second electrode of the first light-emitting element respectively in a first period, to the first electrode of the second light-emitting element and the second electrode of the second light-emitting element respectively in a second period, and to the first electrode of the third light-emitting element and the second electrode of the third light-emitting element respectively in a third period.