Dual-Semiconductor Pixel Circuit for High-Speed Display Driving
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Solution Overview
Problem
Existing light emitting display devices face challenges in maintaining display quality during high-speed driving due to deterioration of charge amounts in storage capacitors and inefficiencies in writing data voltages and compensating for threshold voltages.
Innovation Solution
The device incorporates transistors with polycrystalline and oxide semiconductors, separating layers to form a highly connected pixel structure, and uses a data voltage transmission path through a storage capacitor to indirectly transmit data voltage to the driving transistor, while compensating for threshold voltages through separate transistor operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed driving is implemented, then productivity is improved, but charge amount in storage capacitor deteriorates
Solution Approach 1:
The pixel circuit is segmented into two distinct transistor types: oxide semiconductor transistors for high-speed switching operations and polycrystalline semiconductor transistors for stable current driving. This segmentation allows each transistor type to optimize its function, enabling high-speed driving while maintaining sufficient charge in the storage capacitor through the complementary characteristics of the two materials
Solution Approach 2:
The invention changes the material parameter of the semiconductor from a single type to a dual-material system. By utilizing the high mobility of oxide semiconductors for fast switching and the stability of polycrystalline semiconductors for current control, the system achieves both high-speed operation and adequate charge retention without compromising display quality
2Device complexity
If data voltage transmission and threshold voltage compensation are combined, then device complexity is reduced, but operation efficiency deteriorates
Solution Approach 1:
The operations of data voltage transmission and threshold voltage compensation are segmented into separate transistor operations. The oxide semiconductor transistor is dedicated to high-speed data voltage transmission, while the polycrystalline semiconductor transistor handles threshold voltage compensation. This functional segmentation enables both operations to proceed efficiently without interfering with each other, achieving high-speed driving while maintaining display quality
3Reliability
If oxide semiconductor and polycrystalline semiconductor are used in the same pixel, then display quality is improved, but manufacturing complexity increases
Solution Approach 1:
The invention resolves the manufacturing complexity by separating the oxide semiconductor and polycrystalline semiconductor into different vertical layers within the pixel structure. The oxide semiconductor layer is formed at a lower level, followed by the polycrystalline semiconductor layer above it. This layered arrangement allows both materials to coexist in the same pixel while maintaining independent formation processes, thus improving display quality without excessive manufacturing complexity
Data Source
AI summary
A light emitting display device includes: a light emitting diode; a driving transistor configured to transmit an output current to the light emitting diode, and including a driving gate electrode; a storage capacitor having a first storage electrode connected with the driving gate electrode and a second storage electrode connected with a data node; a second transistor connected with a data line and configured to output a data voltage; a data voltage transmission transistor configured to transmit the data voltage output from the second transistor to the data node; and a hold capacitor that includes a first electrode configured to receive the driving voltage and a second electrode connected with the data node.