Wavelet Matrix Line-by-Line Addressing for LCD Driver Complexity
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Solution Overview
Problem
Existing techniques for displaying a large number of gray shades in liquid crystal displays (LCDs) face challenges with high hardware complexity and increased supply voltage, particularly in amplitude modulation and pulse height modulation methods, which complicate the drivers and increase power consumption.
Innovation Solution
A line-by-line addressing technique using wavelets is proposed, where wavelets with energy proportional to an integer power of two are selected to form a wavelet matrix, allowing for the generation of select and column waveforms that reduce hardware complexity and supply voltage, enabling the display of 128 gray shades with fewer time intervals and voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If amplitude modulation or pulse height modulation is used to display a large number of gray shades, then the number of gray shades displayed increases, but the hardware complexity of drivers increases significantly
Solution Approach 1:
The patent segments the gray shade display into multiple time intervals within each frame period. Instead of using complex amplitude modulation, it divides the frame into discrete time slots where different voltage levels are applied sequentially to pixel rows, enabling gray shade display through time-based segmentation rather than complex hardware modulation
Solution Approach 2:
The patent employs periodic scanning of pixel rows with wavelet-based voltage waveforms. Each row is selected and displayed in periodic time intervals, with the wavelet patterns repeating across frames. This periodic time-based approach replaces the need for complex continuous amplitude modulation hardware while achieving the same gray shade display capability
2Manufacturing precision
If amplitude modulation or pulse height modulation is used to display a large number of gray shades, then the number of gray shades displayed increases, but the supply voltage increases
Solution Approach 1:
The patent uses periodic time-based voltage application with wavelet patterns instead of continuous high-voltage amplitude modulation. By distributing the voltage requirements across multiple time intervals and using the RMS response特性 of liquid crystal pixels, the peak supply voltage is reduced while still achieving the full range of gray shades through integrated energy delivery over time
3Device complexity
If successive approximation technique is used to display a large number of gray shades, then the hardware complexity of drivers is reduced, but the supply voltage increases
Solution Approach 1:
The patent segments the voltage application into multiple time intervals with wavelet patterns, allowing simple binary-like driver outputs to be combined over time to achieve fine gray shade control. This segmentation approach maintains low supply voltage requirements while achieving high precision gray shade display through temporal integration
Solution Approach 2:
The patent employs periodic wavelet-based scanning that repeats across frames, allowing simple periodic voltage switching to accumulate into precise gray shade control through the RMS response of the display medium. This periodic approach achieves high precision without the high supply voltages required by successive approximation methods
Data Source
AI summary
A method for line-by-line addressing of RMS responding display matrix with wavelets, said method comprises steps of: selecting the wavelets such that energy of them is proportional to an integer power of two to form a wavelet matrix; obtaining select waveform profile by summing elements of column in the wavelet matrix; obtaining column waveforms by dot product of data with column of the wavelet matrix; and applying the select waveform and the corresponding column waveforms by selecting one row of the display matrix at a time.