Wire-on-array LCD Gamma Voltage Degradation
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Solution Overview
Problem
Conventional wire-on-array (WOA) displays experience degradation of gamma voltages during transmission, leading to inconsistent source voltages and a banding effect in the display image due to high input current through flexible printed circuit boards.
Innovation Solution
Incorporating high input impedance components, such as operational amplifiers, within the source driver circuits to receive and transmit gamma voltages with minimal input current, ensuring almost identical voltage levels are maintained across all source driver circuits, thereby reducing voltage degradation and eliminating the banding effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gamma voltages are transmitted through flexible printed circuit boards to source driver circuits, then signals can be delivered to all source driver circuits, but voltage degradation occurs due to high input current causing inconsistent source voltages and banding effect
Solution Approach 1:
A buffer circuit is introduced as an intermediary component between the flexible printed circuit board and the source driver circuits. The buffer circuit receives gamma voltages from the FPC and provides them to multiple source driver circuits with high input impedance, preventing voltage degradation by minimizing current draw from the FPC while still enabling signal distribution to all source driver circuits.
2Reliability
If multiple flexible printed circuit boards are used to connect source driver circuits, then each source driver circuit can receive signals independently, but manufacturing cost increases
Solution Approach 1:
Multiple source driver circuits are connected in series along the flexible printed circuit board, merging their signal reception paths into a single FPC. The buffer circuit at the front end distributes gamma voltages to all source driver circuits through this series configuration, reducing the number of FPCs from multiple to just one, thereby lowering manufacturing cost while maintaining signal transmission reliability.
Data Source
AI summary
A wire-on-array (WOA) flat panel display is provided. The wire-on-array (WOA) flat panel display is characterized in a plurality of high input impedance components between the flexible printed circuit (FPC) board and the corresponding source driver circuits. Each of the high input impedance components is able to receive gamma voltages with little input current and then transmit the gamma voltages to each of the source driver circuit for production of source voltages of little banding effect.