Stage Circuit Voltage Segmentation for Stable Scan Signals
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Solution Overview
Problem
Existing display devices face challenges in reducing power consumption and stabilizing scan signal supply across different driving frequencies and areas, particularly in applications requiring varied image refresh rates.
Innovation Solution
A stage circuit design that includes input and output units, voltage controllers, and transistors configured to handle auxiliary and main power sources with different voltage levels, allowing for synchronized scan signal generation with varying frequencies and polarities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single power source is used for scan signal generation, then device complexity is reduced, but power consumption cannot be optimized across different driving frequencies
Solution Approach 1:
The power source system is segmented into a first power source and a second power source with different voltage levels. The first power source is used for generating scan signals at a first driving frequency, while the second power source is used for generating scan signals at a second driving frequency. This segmentation allows each power source to be optimized for specific frequency ranges, reducing overall power consumption while maintaining manageable device complexity through systematic power management.
2Reliability
If voltage levels are kept uniform across all nodes, then device complexity is reduced, but scan signal stability cannot be maintained across different driving frequencies
Solution Approach 1:
Different voltage levels are applied to different nodes based on their specific functional requirements and driving frequency demands. The first node receives a first voltage level optimized for first driving frequency operation, while the second node receives a second voltage level optimized for second driving frequency operation. This localized voltage optimization ensures scan signal stability across varying frequencies while the voltage controllers manage the complexity of maintaining appropriate voltage levels at each node.
3Adaptability or versatility
If a simple output structure is used, then device complexity is reduced, but the ability to output scan signals with different polarities is limited
Solution Approach 1:
The output units are designed with multi-functionality to handle various scan signal requirements. Each output unit can operate in multiple modes: outputting scan signals generated from the first power source with first polarity, outputting scan signals generated from the second power source with second polarity, and coordinating between power sources to maintain signal stability. This universal design enables the output structure to adapt to different polarity requirements without proportionally increasing device complexity.
Data Source
AI summary
A display device includes: a display unit including pixels located to be connected to scan lines and data lines; and a scan driver including stage circuits to drive the scan lines, wherein the stage circuits are configured to: generate a carry signal, using an auxiliary clock signal swinging between a first voltage and a second voltage, a first auxiliary power source having the first voltage, and a second auxiliary power source having the second voltage; and generate a scan signal, using a clock signal swinging between a third voltage higher than the first voltage and a fourth voltage lower than the second voltage, a first power source having the third voltage, and a second power source having the fourth voltage.