LCD Pixel Charging via Corrected Voltage Memory
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display (LCD) pixels experience slow rotation speed of liquid crystal molecules, leading to 'short charge time' or 'short response time,' causing blurring of images with fast-changing scenes, and the conventional high pre-charge voltage method requires high voltage and can result in incorrect gray scale levels and 'after images' when transitioning between white and black.
Innovation Solution
A method and device for selectively charging LCD pixels to intended gray scale levels at the end of a horizontal period without initial high pre-charging voltage, using corrected charge voltage values stored in memory, which allows for half driving speed and avoids side effects like after images, by applying either positive or negative corrected charge voltage based on pixel location and polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If initial high pre-charge voltage is applied to compensate charge time, then pixel charging speed is improved, but voltage level control precision deteriorates and after images occur
Solution Approach 1:
The patent applies preliminary action by pre-charging pixels to intermediate gray scale levels before the final data voltage is applied. This is achieved through a pre-charge period where pixels are charged to predetermined intermediate levels, then during the data period the voltage is adjusted to the final target level. This two-stage approach allows faster charging without requiring excessive high voltage that would cause after images and gray scale errors.
2Reliability
If horizontal period is divided into pre-charge period and real data period, then charging completeness is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the horizontal period into two distinct time periods: a pre-charge period and a real data period. During the pre-charge period, pixels are charged to intermediate gray scale levels. During the real data period, the voltage is adjusted to the final target level. This temporal segmentation allows reliable charging completion without requiring complex circuitry, as the same driver circuit simply operates in different modes during different periods.
3Loss of time
If conventional high pre-charge voltage is used, then response time is improved, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by varying the voltage level during different time periods. Instead of applying a constant high pre-charge voltage throughout, the system changes the voltage parameter to intermediate levels during the pre-charge period and then adjusts to the final target level during the data period. This dynamic parameter adjustment achieves fast response time while minimizing energy consumption compared to sustained high voltage operation.
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 enables faster pixel charging without high voltage overdrive, reduces after images, and maintains accurate gray scale levels, while reducing the number of drivers needed and saving charging time compared to conventional methods.
Implementation Method 1
The liquid crystal molecules are aligned between the two polarizing filter films and the axis of the filters may be perpendicular or parallel from each other. Here, the rotation of the liquid crystal molecules is modulated by the electrical setting because each liquid crystal molecule is aligned along with an electric field which can be made by the electrical setting for an individual pixel.
Data Source
AI summary
A liquid crystal display (LCD) device and a method for driving LCD. Such a device may have a plurality of LCD pixels in a matrix, a driver that inputs a drive signal to each pixel selectively and a controller that controls a level and a polarity of the drive signal, and a memory storing corrected charge voltage values. Each pixel is provided with the drive signal based on the corrected charge voltage values for the corresponding pixel during the entirety of a horizontal period, and the corrected charge voltage value has a predetermined value corresponding to a charge for an intended gray scale level of the pixel at the end of the horizontal period without an over shooting of the driving voltage. When the target gray scale of the pixels is at the brightest level, a predetermined negative corrected charge is applied to the pixel to avoid an after image.