LCD Driving Method Using Pre-Tilt and Overdrive for Response Speed
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Solution Overview
Problem
Liquid crystal display (LCD) devices struggle to optimize the response speed of liquid crystal molecules, leading to blurred moving images due to slower response times compared to motion picture frame periods.
Innovation Solution
A driving method for LCDs that calculates a compensated gradation datum based on the difference between consecutive frames, using a combination of pre-tilt and overdrive values stored in look-up tables to adjust the voltage applied to liquid crystal molecules, optimizing their response speed by varying the pre-tilt value and overdriving quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional driving methods are used, then the LCD structure remains simple, but the response speed of liquid crystal molecules is slow causing blurred moving images
Solution Approach 1:
The patent applies pre-tilting action by outputting a pre-tilt forming signal before the main gradation signal to pre-arrange liquid crystal molecules in a tilted state, preparing them for faster response when the main signal is applied. This preliminary action reduces the time needed for molecules to reach their final orientation, improving response speed without compromising display quality
Solution Approach 2:
The patent implements dynamic overdrive mode that adaptively adjusts driving currents based on the difference between current and previous frame gradation data. By dynamically changing the drive current magnitude according to the specific transition required, the system optimizes response speed for each individual pixel transition while maintaining accurate final display states
2Speed
If fixed pre-tilting values are used in LUT, then the driving circuit is simple, but the response speed between detail gradations is not optimized
Solution Approach 1:
The patent segments the pre-tilting values into multiple distinct entries in the LUT, with each entry corresponding to specific gradation transition scenarios. Instead of using a single fixed pre-tilt value, the system divides the control into multiple specialized pre-tilt settings that can be selectively applied based on the specific gradation change required, optimizing response for each detail transition
Solution Approach 2:
The patent applies different pre-tilting values tailored to specific local conditions of gradation transitions. By storing multiple pre-tilt values in the LUT that correspond to different current and previous frame gradation combinations, the system provides locally optimized pre-tilting for each specific transition scenario rather than applying a uniform approach, thereby optimizing response speed for detail gradations
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 enhances the response speed of liquid crystal molecules, particularly between detail gradations, resulting in clearer display of moving images without altering the LCD structure or liquid crystal molecules, thereby improving moving picture quality.
Implementation Method 1
When an electric field is applied between the common electrode and the pixel electrode, the arrangement of liquid crystal molecules interposed between the common electrode and the pixel electrode is changed
Data Source
AI summary
A liquid crystal display (LCD) apparatus includes an LCD section and a driving section. The driving section provides the LCD section with a compensated gradation datum based on a first gradation datum of an (n)-th frame, a second gradation datum of an (n+1)-th frame and a third gradation datum of an (n−1)-th frame. The driving section provides the LCD section with a sum total of a pre-tilt value that is varied in accordance with the gradation and the first gradation datum when the gradation of the second gradation datum is higher than that of the first gradation datum. The driving section provides the LCD section with the first gradation datum when a gradation of the second gradation datum is lower than that of the first gradation datum.