LCD Data Driver Circuit for Column Inversion Driving
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Solution Overview
Problem
The 3-column inversion driving method for liquid crystal displays increases the size of the driving circuit and manufacturing costs due to asymmetric charging and potential greenish tint issues.
Innovation Solution
A liquid crystal display employing a data driver with a digital-to-analog converting unit that includes both positive and negative digital-to-analog converters, along with a data latch that rearranges image data sequences, allowing for inversion driving without increasing the circuit size by using column or 3-column inversion methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 3-column inversion driving is used, then asymmetric charging and greenish tint issues are addressed, but the driving circuit size increases and manufacturing cost increases
Solution Approach 1:
The data latch is designed to perform multiple functions: it can operate in normal mode for standard data output and in inversion mode for 3-column inversion driving. By integrating both functionalities into a single circuit block, the patent achieves multi-functionality without increasing overall circuit size, resolving the contradiction between reliability improvement and device complexity.
Solution Approach 2:
The data latch incorporates a mode selection mechanism that dynamically switches between normal operation and 3-column inversion operation. The circuit adapts its behavior based on the selected mode, enabling flexible polarity control across different columns while maintaining a compact circuit structure, thus addressing display quality issues without permanently increasing circuit complexity.
2Reliability
If 3-column inversion driving is used, then asymmetric charging issues are resolved, but manufacturing cost increases
Solution Approach 1:
The data driver circuit is designed as a universal circuit that can handle both normal driving and 3-column inversion driving modes. This multi-functional design eliminates the need for separate circuits for different driving modes, thereby simplifying the manufacturing process and reducing costs while still achieving symmetric charging through 3-column inversion when needed.
Solution Approach 2:
The patent changes the operational parameters of the data latch by switching between different output modes (normal mode and inversion mode). By adjusting these operational parameters rather than changing the physical circuit structure, the system achieves symmetric charging without requiring additional manufacturing steps or components, thus maintaining cost-effectiveness.
Data Source
AI summary
A liquid crystal display includes a plurality of pixels, a plurality of data lines connected to the plurality of pixels, and a data driver connected to the plurality of data lines, where the data driver supplies data voltage to the plurality of data lines, where the data driver includes a data latch which outputs input image data in response to image data corresponding to the plurality of pixels, wherein the data latch rearranges a sequence of the image data, and a digital-to-analog converting unit which includes a positive digital-to-analog converter which generates a positive data voltage in response to the input image data, and a negative digital-to-analog converter which generates a negative data voltage in response to the input image data.