OLED Display Substrate Layout for High-PPI Compensation Circuits
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Solution Overview
Problem
Internal compensation pixel circuits in medium-sized and large-sized OLED displays face challenges in achieving high pixels per inch (PPI) due to their complexity, making it difficult to optimize display performance.
Innovation Solution
A display substrate design with a specific arrangement of sub-pixels and pixel circuits, including a driving transistor and light-emitting element, where the orthographic projections of electrodes and capacitors are carefully aligned to minimize overlap and optimize signal transmission, along with a driving method that includes reset, compensation, data writing, and light-emitting phases to enhance display efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If internal compensation pixel circuits are used in medium-sized and large-sized OLED displays, then driving system cost is reduced and integration is improved, but pixel circuit complexity increases making it difficult to achieve high pixels per inch
Solution Approach 1:
The patent extracts the compensation function from the pixel circuit by placing the compensation capacitor outside the pixel circuit boundary. This allows the pixel circuit to use fewer transistors (reducing complexity and enabling higher PPI) while the external compensation capacitor handles the compensation function, thus maintaining cost-effectiveness without increasing pixel circuit complexity.
Solution Approach 2:
The patent implements a nested structure where the compensation capacitor is positioned beneath or adjacent to the pixel circuit components, creating a layered configuration. This nested arrangement allows efficient use of space, reducing the overall area occupied by compensation components while maintaining the internal compensation functionality, thereby supporting higher pixel density without excessive complexity.
2Adaptability or versatility
If internal compensation pixel circuits are used, then integration is improved, but pixel circuit complexity increases making it difficult to achieve high pixels per inch
Solution Approach 1:
The compensation function is extracted from the pixel circuit and implemented externally, allowing the pixel circuit to maintain low complexity while achieving high integration. The external compensation capacitor provides the necessary compensation functionality without requiring additional transistors within the pixel circuit, thus enabling higher PPI while maintaining integration benefits.
Solution Approach 2:
The patent utilizes vertical stacking and layered structures to achieve integration without increasing planar complexity. By arranging compensation components in three-dimensional space beneath or adjacent to pixel circuit elements, the design achieves high integration density while keeping the two-dimensional pixel circuit layout simple and compact.
Data Source
AI summary
Provided are a display substrate and a display device. The display substrate includes a base substrate and a plurality of sub-pixels, the sub-pixel includes a pixel circuit and a light-emitting element, the pixel circuit is configured to drive the light-emitting element, and the light-emitting element includes a first electrode, a second electrode, and a light-emitting functional layer located therebetween; the pixel circuit includes a driving transistor, and the first electrode of the light-emitting element is electrically connected to a first electrode of the driving transistor; the plurality of sub-pixels include a first sub-pixel and a second sub-pixel, the first sub-pixel is adjacent to the second sub-pixel, and an orthographic projection of the first electrode of the light-emitting element of the first sub-pixel on the base substrate does not overlap an orthographic projection of the pixel circuit of the second sub-pixel on the base substrate.