Gamma-Voltage Generator Single Buffer Switching
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Solution Overview
Problem
Conventional liquid crystal display driving circuits utilize different gamma buffers for outputting gamma voltages, resulting in errors between input and output voltages, which deteriorate display quality by causing deviations from ideal gamma voltage curves and root mean square (RMS) relationships.
Innovation Solution
A gamma-voltage generator that uses a single gamma buffer to output gamma voltages during different frame periods, with digital-to-analog converters (DACs) and switching circuits to ensure that both positive and negative polarity gamma voltages are buffered equally, minimizing output errors and maintaining ideal gamma voltage and RMS relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different gamma buffers are used for positive and negative polarity gamma voltages, then the display can drive pixels with different polarities, but the errors between input and output voltages increase, deteriorating display quality
Solution Approach 1:
The patent merges the function of multiple gamma buffers (separate for positive and negative polarities) into a single gamma buffer that handles both polarities. This is achieved by using a switching circuit that alternately connects the single gamma buffer to different pixel groups during different frame periods, thereby reducing the number of buffers while maintaining the ability to drive both positive and negative polarity pixels with consistent voltage accuracy
Solution Approach 2:
The patent introduces dynamic switching between different connection configurations of the single gamma buffer. The switching circuit dynamically connects the gamma buffer to different pixel groups (odd/even lines or columns) during different frame periods, allowing the same buffer to serve multiple functions while maintaining signal integrity and reducing static errors associated with multiple separate buffers
2Adaptability or versatility
If multiple gamma buffers are used, then different polarity voltages can be buffered separately, but the device complexity increases
Solution Approach 1:
The single gamma buffer is designed to perform multiple functions by serving different pixel groups at different times. The buffer handles both positive and negative polarity gamma voltages, and through the switching circuit, it can serve odd-numbered pixel groups during one frame period and even-numbered pixel groups during the next frame period, thereby replacing multiple specialized buffers with one universal buffer
Solution Approach 2:
The patent combines multiple gamma buffers into a single buffer unit, reducing the overall device complexity. The switching circuit enables this single buffer to be shared between different pixel groups, effectively merging the functionality of what would traditionally require separate buffers for positive and negative polarities
3Device complexity
If a single gamma buffer is used for both polarities, then device complexity is reduced, but ensuring equal buffering performance for both polarities becomes more difficult
Solution Approach 1:
The patent employs periodic switching between different pixel group configurations. The single gamma buffer serves odd-numbered pixel groups during one frame period and even-numbered pixel groups during the next frame period, creating a periodic pattern that ensures both groups receive equally treated signals over time, thereby maintaining equal offset and buffering performance for both polarities
Solution Approach 2:
The switching circuit is controlled based on frame period timing signals that ensure alternating connection patterns. This periodic control mechanism provides a form of feedback-based management where the system automatically alternates the buffer connection to maintain balanced performance across different pixel groups, ensuring equal treatment of both positive and negative polarity voltages
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that gamma voltages have substantially equal offsets, thereby improving display quality to ideal conditions by eliminating the errors present in conventional systems, resulting in closer alignment with ideal gamma voltage and RMS curves.
Implementation Method 1
a plurality of digital-to-analog converters (DACs) convert a digital signal into a plurality of gamma voltages
Implementation Method 2
The gamma buffers are coupled to the DACs for buffering the gamma voltages and outputting the buffered gamma voltages
Data Source
AI summary
A gamma-voltage generator is provided to generating a plurality of first gamma voltages and second gamma voltages. At least one of the first gamma voltages generated by DACs of the gamma-voltage generator within a first frame period and at least one of the second gamma voltages generated by the DACs within a second frame period are outputted from a same one of the gamma buffers of the gamma-voltage generator, whereby the transmitted gamma voltages have substantially equal offset. Therefore, the display quality approaches an ideal condition.