MVA Liquid Crystal Display Driving Method for Black-to-White Response
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Solution Overview
Problem
MVA type liquid crystal display panels face issues with slow response speed when converting black display to white, leading to brightness over-shoot and poor display frames due to the lack of grinding treatment on alignment films and excessive rotation torque at higher drive voltages.
Innovation Solution
A liquid crystal display device with protrusions acting as local restriction mechanisms, combined with a drive circuit that applies a drive voltage waveform where the voltage is higher in the first half of the frame period and equal to or lower than the target voltage in the second half, and temperature compensation to adjust voltage values, ensuring rapid response and minimizing over-shoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the drive voltage is increased to achieve faster response speed when converting black display to white display, then the response speed is improved, but brightness over-shoot occurs causing poor display frames
Solution Approach 1:
The patent applies periodic action by dividing the frame period into multiple time periods with different drive voltage levels. The drive voltage is applied in a periodic manner: higher voltage in the first time period to accelerate response, then reduced to target voltage in subsequent periods to maintain stability and prevent over-shoot. This temporal segmentation of voltage application resolves the contradiction between fast response and avoiding brightness over-shoot.
Solution Approach 2:
The patent implements dynamics by making the drive voltage adjustable and time-dependent rather than static. The drive voltage dynamically changes throughout the frame period, being higher initially to overcome the slow response of MVA liquid crystal molecules, then transitioning to the target voltage level. This dynamic voltage control allows the system to adapt to different stages of liquid crystal molecule rotation, achieving both fast response and stable display.
2Adaptability or versatility
If the MVA type liquid crystal display panel uses protrusions to achieve multi-domain vertical alignment and wide viewing angle, then the viewing angle is improved, but the response speed when converting black to white display becomes slower
Solution Approach 1:
The patent applies preliminary action by pre-positioning protrusions on the electrode surfaces before liquid crystal molecules are aligned. These protrusions create predetermined tilt directions that guide liquid crystal molecule orientation. When voltage is applied, molecules rotate along these pre-established paths, enabling multi-domain vertical alignment for wide viewing angles while maintaining controllable response characteristics through the staged voltage approach.
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 significantly shortens the response time when converting black to white displays, reduces brightness over-shoot, and maintains a stable display frame without adverse impacts.
Implementation Method 1
a liquid crystal display device having negative dielectric anisotropy
Data Source
AI summary
A liquid crystal display device and a driving method thereof are provided. The driving circuit of the liquid crystal display device outputs a drive voltage applied between the first electrode and the second electrode of a sub-pixel of a display panel. When a transmittance of the sub-pixel is changed from a transmittance value to another transmittance value higher than the transmittance value in a first frame period, the drive voltage applied between the first electrode and the second electrode is lower than or equal to a target drive voltage corresponding to the another transmittance value in a front half period of the first frame period, the drive voltage is higher than the target drive voltage in a rear half period of the first frame period, and the drive voltage is equal to the target drive voltage in other frame periods after the first frame period.