Level Conversion Circuit for Display Row Voltage Uniformity
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Solution Overview
Problem
Thin film transistor liquid crystal displays experience vertical line defects due to differences in charging voltages across rows, caused by variations in resistances and process characteristics, leading to uneven brightness across the panel.
Innovation Solution
A level conversion circuit comprising a level conversion sub-circuit, a power supply switch sub-circuit, and a controller, which receives input signals and selects appropriate driving levels from candidate levels to ensure independent and balanced driving signals for odd- and even-numbered rows, mitigating voltage differences and enhancing display uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple cascaded shift register circuit is used to reduce production cost, then manufacturing cost is reduced, but charging voltage uniformity across rows deteriorates due to resistance differences and process variations
Solution Approach 1:
The pixel array is divided into multiple groups (e.g., odd-numbered rows and even-numbered rows), with each group having an independent shift register and level conversion circuit. This segmentation allows separate control of charging voltages for different row groups, compensating for process variations and resistance differences without requiring a completely new circuit architecture, thus maintaining cost-effectiveness while improving voltage uniformity.
Solution Approach 2:
Different charging voltage levels are applied to different row groups based on their specific characteristics. The level conversion circuits adjust the output voltages locally for each shift register group, ensuring that each group receives the appropriate voltage level needed to compensate for its specific resistance and process characteristics, thereby achieving overall voltage uniformity across the panel.
2Manufacturing precision
If independent driving signals are provided to different shift register groups to improve display uniformity, then charging voltage uniformity is improved, but device complexity increases due to additional level conversion circuits
Solution Approach 1:
Level conversion circuits are introduced as intermediary components between the main control signals and the shift registers. These intermediaries translate the control signals into appropriate voltage levels for each shift register group, enabling independent voltage control without requiring complete redesign of the driving circuit architecture. This intermediary approach adds minimal complexity while achieving the goal of improved display uniformity.
Solution Approach 2:
The level conversion circuits are designed with universal functionality to handle multiple signal types (frame start signals and clock control signals) and can be applied to any shift register group. This multi-functionality reduces the need for specialized circuits for each group, thereby limiting the increase in overall device complexity while still providing the necessary independent control for improved display uniformity.
3Adaptability or versatility
If multiple candidate voltage levels are provided and selected based on control signals, then adaptability to different process characteristics is improved, but power consumption increases due to additional switching operations
Solution Approach 1:
The system dynamically selects from multiple candidate voltage levels based on control signals that reflect actual process characteristics and resistance variations. This dynamic adaptation allows the circuit to optimize performance for different operating conditions without maintaining all voltage levels simultaneously active, thereby achieving high adaptability while limiting additional power consumption through selective activation.
Solution Approach 2:
The system changes the voltage level parameter of the driving signals based on control signals and detected process characteristics. By adjusting the voltage level parameter dynamically rather than maintaining fixed high levels, the system achieves adaptability to different process variations while minimizing power consumption through parameter optimization rather than constant high-power operation.
Data Source
AI summary
The present disclosure provides a level conversion circuit, a display apparatus, and a driving method. The level conversion circuit includes a level conversion sub-circuit, a power supply switch sub-circuit, and a controller. The level conversion sub-circuit is connected to a first input terminal, the power supply switch sub-circuit, and an output terminal, respectively, and is configured to receive a first signal, receive a first driving level from the power supply switch sub-circuit, convert the received first signal into the first driving level, and output the first driving level to the output terminal. The power supply switch sub-circuit is further connected to the controller and is configured to receive N candidate first levels, receive a control signal from the controller, select one of the N candidate first levels as the first driving level according to the received control signal, and output the selected first driving level to the level conversion sub-circuit, where N is an integer greater than or equal to 2.