OLED Display Backplane Layout for Uniformity and Narrow Bezels
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Solution Overview
Problem
Large-sized display panels using organic light-emitting diodes face challenges in achieving uniform image quality and have a wide frame, which limits the screen-to-body ratio.
Innovation Solution
A display panel design incorporating a driving backplane with pixel and peripheral circuits, utilizing metal oxide and polysilicon transistors, and a specific configuration of shift registers, reset circuits, and light-emitting devices to enhance signal transmission and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional transistor materials are used in pixel circuits, then manufacturing process is simpler, but image quality uniformity is poor and threshold voltage instability occurs
Solution Approach 1:
The patent divides the transistor system into two segments: polysilicon transistors for the shift register (peripheral circuit) and metal oxide transistors for the pixel circuit. This segmentation allows each segment to use optimized transistor types for its specific function, achieving high image quality uniformity in the display area while maintaining manageable overall device complexity through clear functional separation.
Solution Approach 2:
The patent applies different transistor material qualities to different locations: metal oxide transistors with superior electrical characteristics are used specifically in the pixel circuit where image quality uniformity is critical, while polysilicon transistors are used in the peripheral circuit where high-speed switching is prioritized. This local quality differentiation resolves the contradiction by optimizing each region for its primary function.
2Area of stationary object
If frame width is reduced to increase screen-to-body ratio, then display area increases, but peripheral circuit layout becomes more constrained
Solution Approach 1:
The patent utilizes the vertical dimension by stacking the pixel circuit and shift register in different spatial layers. The shift register is positioned in the peripheral area surrounding the pixel circuit, allowing efficient use of peripheral space without increasing overall device footprint. This dimensional arrangement enables narrow-frame design while maintaining proper circuit layout.
Solution Approach 2:
The patent employs dynamic signal transmission through the shift register that scans pixel rows sequentially. This dynamic scanning approach allows the peripheral circuit to efficiently control the entire display area without requiring excessive peripheral space, as signals are transmitted through time-multiplexed scanning rather than requiring static connections to all pixels.
3Stability of the object's composition
If metal oxide transistors are used in pixel circuit, then threshold voltage stability improves, but transistor fabrication complexity increases
Solution Approach 1:
The patent segments the fabrication process into two streams: a metal oxide transistor fabrication process for the pixel circuit that ensures threshold voltage stability, and a polysilicon transistor fabrication process for the shift register that prioritizes manufacturing simplicity. This segmented approach allows each transistor type to be optimized for its specific requirements while using established fabrication techniques for both, thereby reducing overall fabrication complexity compared to using metal oxide transistors throughout the entire device.
Data Source
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AI summary
The present disclosure relates to a display panel and a display device, and relates to the field of display technology. The display panel includes a driving backplane and a light-emitting device; the driving backplane has a pixel circuit located in a display area and a peripheral circuit located in a peripheral area, and the peripheral circuit includes a plurality of cascaded shift registers; a shift register is configured to scan at least one row of pixel circuits; the pixel circuit and the shift register both include a plurality of transistors; the transistors of the pixel circuit include a driving transistor, and the driving transistor and at least some of the other transistors are metal oxide transistors; the transistors in the shift register are polysilicon transistors; the light-emitting device is arranged on one side of the driving backplane; the light-emitting device includes a first electrode, a light-emitting layer, and a second electrode stacked in sequence in a direction away from the driving backplane; the first electrode of the driving transistor is connected to the first electrode of the light-emitting device, the second electrode is connected to the first power line transmitting the first power signal, and the second electrode of the light-emitting device is configured to receive the second power signal.