LCD Image Signal Modifier for Response Time
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Solution Overview
Problem
Liquid crystal displays (LCDs) face a slow response time, particularly as display size and resolution increase, leading to delays in image rendering, and existing methods to address this, such as applying overshoot or undershoot voltages, result in decreased luminance when in normally black mode.
Innovation Solution
An image signal modifier generates a modified signal based on previous, current, and next image signals, allowing the data driver to apply data voltages that are either higher or lower than the target voltage to improve response time without compromising luminance, using a combination of lookup tables and interpolation to determine optimal voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If overshoot voltage is applied to compensate for slow response time, then response time is improved, but luminance decreases when in normally black mode
Solution Approach 1:
The patent applies preliminary action by pre-charging the liquid crystal capacitor to a first voltage level before the actual image signal is applied. This preliminary voltage application prepares the liquid crystal molecules for faster reorientation, reducing response time without requiring excessive overshoot voltages that would compromise luminance. The pre-charge voltage is specifically controlled to be higher than the final target voltage, enabling rapid transition while maintaining proper light emission intensity.
2Speed
If data voltage is increased to improve response time, then response time is improved, but image quality deteriorates due to luminance loss
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the voltage levels based on the relationship between current and next image signals. When the next image signal is brighter than the current signal, the system applies a higher pre-charge voltage to accelerate molecular reorientation. When the next signal is darker, the voltage is reduced accordingly. This adaptive parameter adjustment optimizes response time while preventing luminance degradation and maintaining image quality across different transition scenarios.
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 time of LCDs by ensuring liquid crystal molecules can rapidly reorient to achieve target light transmittance levels, improving image quality and reducing delays in displaying moving images without sacrificing luminance.
Implementation Method 1
a liquid crystal (LC) layer having dielectric anisotropy that is disposed between the two panels
Implementation Method 2
The field generating electrodes generate an electric field in response to applied voltages and liquid crystals disposed therebetween form a so-called liquid crystal capacitor
Data Source
AI summary
A liquid crystal display with improved response time and a method of making such display are presented. The invention improves the quality of moving images. The display includes a plurality of pixels, an image signal modifier for generating a preliminary signal based on a previous image signal and a current image signal and generating a modified image signal based on the preliminary signal and a next image signal, and a data driver for changing the modified image signal from the image signal modifier into a data voltage and supplying it to the pixels. The value of the modified image signal is set according to the magnitude of the next image signal.