TFT-LCD Driving Method Reducing Frame Buffer Memory
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Solution Overview
Problem
TFT-LCD driving methods using the over-drive technique require expensive frame buffers and large memory capacity for Look-Up Tables, increasing manufacturing costs and power consumption, especially for motion picture displays where rapid gray level changes are necessary.
Innovation Solution
A TFT-LCD driving method that applies a bias voltage to change the gray level to a baseline level, then converts the target gray level voltage to an over-drive voltage, eliminating the need for frame buffers and simplifying memory requirements by using a single column of the Look-Up Table or a transformation formula, thereby reducing costs and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the over-drive technique is employed to increase the changing rate of gray level, then the display quality for motion pictures is improved, but the manufacturing cost increases due to the need for frame buffers and large memory capacity
Solution Approach 1:
The patent extracts and eliminates the frame buffer component from the system by using a simplified driving method that processes image data sequentially without requiring storage of previous frames. This removes the need for expensive frame buffer memory while maintaining the over-drive technique's ability to achieve rapid gray level changes for motion picture display quality
Solution Approach 2:
The patent replaces the expensive frame buffer with a disposable approach where image data is processed line by line or pixel by pixel without needing to be stored. The Look-Up Table is also simplified to use only one column instead of requiring large memory capacity, reducing manufacturing cost while maintaining functionality
2Speed
If the over-drive technique is used to achieve rapid gray level changes, then the changing rate is improved, but the memory capacity requirement increases due to the expanded Look-Up Table
Solution Approach 1:
The patent extracts only the essential column from the traditional two-column Look-Up Table structure, eliminating the need to store both initial and target gray level voltages. By processing image data sequentially and using a single column that maps to over-drive voltages, the memory capacity is dramatically reduced while maintaining the speed of gray level changes
Solution Approach 2:
The patent performs preliminary conversion of target gray level voltages to over-drive voltages using a simplified Look-Up Table before the actual display update. This preliminary action enables rapid gray level changes without requiring large memory capacity, as the conversion is pre-computed and stored in a compact table
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 method allows for rapid achievement of target gray levels without frame buffers, minimizes memory capacity, reduces manufacturing costs, and enhances motion picture display quality by reducing blurring effects.
Implementation Method 1
When an appropriate gray level voltage is applied to a pixel in a TFT LCD panel, the angle of liquid crystal molecule in the pixel will change correspondingly. This angle change further alters transmittance of the TFT-LCD panel so a desired gray level can be achieved.
Data Source
AI summary
A method for driving a TFT-LCD, includes first applying a bias voltage to a pixel so the gray level displayed by the pixel changes from an initial gray level to a baseline gray level. A target gray level voltage is then converted to a corresponding over-drive gray level voltage. Subsequently, the over-drive gray level voltage is applied to the pixel so the gray level displayed by the pixel changes from the baseline gray level to the target gray level.