Cholesteric Liquid Crystal Display Driving Method for Uniform Brightness
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Solution Overview
Problem
Cholesteric liquid crystal display devices suffer from non-uniform image quality due to varying voltage applications across row electrode lines, leading to differences in liquid crystal molecule orientation and reflectivity, resulting in inconsistent brightness and image quality.
Innovation Solution
A cholesteric liquid crystal display device with a liquid crystal driving unit that applies column driving voltages to column electrode lines and addresses row electrode lines with a sequence of select and non-select voltages, with a modification time increment of more than eighteen times the select unit time for the non-select voltage to ensure uniform image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If row electrode lines are scanned sequentially with select voltage followed by non-select voltage, then the display can be addressed in a passive matrix configuration, but the accumulative non-select times vary across different rows causing non-uniform liquid crystal molecule orientation and non-uniform brightness
Solution Approach 1:
The patent applies a preliminary action by extending the non-select voltage application time before the normal scanning sequence. Specifically, after scanning all row electrode lines with select voltage, the system continues to apply non-select voltage for an additional period (at least 18 scan unit times) to ensure all liquid crystal molecules return to their initial state before the next frame begins. This preliminary extended action compensates for the varying accumulative non-select times across different rows, achieving uniform brightness while maintaining passive matrix addressing simplicity
2Illumination intensity
If the non-select voltage is applied for a longer duration to equalize liquid crystal molecule orientation across all rows, then brightness uniformity improves, but the frame scan time increases
Solution Approach 1:
The patent applies partial or excessive action by extending the non-select voltage application to at least 18 scan unit times, which is more than the minimum time needed for liquid crystal molecule relaxation. This excessive time extension ensures that even the row with the maximum accumulative non-select time (M-1 rows) has sufficient time for molecule reorientation, achieving uniform brightness. The specific value of 18 times is determined to be the optimal balance between achieving uniformity and minimizing the time penalty
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
The solution achieves significantly more uniform brightness and consistent image quality by ensuring sufficient energy is applied to all liquid crystal molecules, reducing the differences in reflectivity and enhancing overall display performance.
Implementation Method 1
a cholesteric liquid crystal display panel, and the cholesteric liquid crystal display panel has pixels where are intersected between a plurality of column electrode lines and a plurality of row electrode lines
Implementation Method 2
orientations of the liquid crystal molecules are different because voltage built-up at the liquid crystal molecules are different so that liquid crystal reflectivity seems higher and brightness seems higher
Data Source
AI summary
A cholesteric liquid crystal display device and a driving method for improving non-uniform image quality of the cholesteric liquid crystal display device. The cholesteric liquid crystal display device includes a cholesteric liquid crystal display panel and a liquid crystal drive unit. The cholesteric liquid crystal display panel is composed of multiple row circuit structures and multiple column circuit structures. The liquid crystal driving unit sequentially outputs column driving voltages to a plurality of column circuit structures in a scanning manner. After scanning the multiple column circuit structures, the liquid crystal driving unit applies an unselected voltage to the multiple column circuit structures together with more than 18 times the scanning unit time course, so as to make the brightness of the overall picture more uniform.