Display Signal Controller Pre-Charging for High Resolution
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Solution Overview
Problem
As display device resolution increases, the charging time of each pixel at the data voltage decreases, particularly when polarity inversion is employed, leading to insufficient time to reach target data voltages, resulting in image quality defects like mixed color horizontal or vertical lines due to deviations in charging ratios between pixels.
Innovation Solution
The implementation of a display device with a signal controller that corrects input image signals to include a first gray scale value greater than 0 for black data voltages, using pre-charging methods where pixels in different rows or columns are connected to the same data line, and employing a lookup table to adjust voltages to prevent luminance deviations, thereby reducing charging ratio deviations and image quality defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resolution of display device is increased, then image quality is improved, but charging time of each pixel decreases
Solution Approach 1:
The patent applies pre-charging by transferring a pre-charge voltage to pixels before the target data voltage is applied. This preliminary action allows pixels to be partially charged in advance, so when the main charging occurs, pixels can reach target voltages faster. This is particularly important for high-resolution displays where charging time is limited, enabling sufficient charging even when polarity inversion is employed.
2Reliability
If polarity inversion is employed, then deterioration of liquid crystal layer is prevented, but time to charge data voltage increases
Solution Approach 1:
The patent implements pre-charging before polarity inversion occurs. By transferring a pre-charge voltage to pixels before the main data voltage application, the system ensures that even when polarity inversion is used to prevent liquid crystal deterioration, pixels have sufficient time to reach target voltages. The pre-charged pixels can rapidly reach target luminance levels during the main charging phase.
3Speed
If pre-charge voltage is transferred before target data voltage, then charging speed is improved, but luminance deviation may occur
Solution Approach 1:
The patent adjusts the pre-charge voltage level based on the target data voltage. When the target data voltage corresponds to a low gray scale value (including black), the pre-charge voltage is set to a level that prevents over-charging and subsequent luminance deviation. This dynamic parameter adjustment ensures that pre-charging accelerates charging speed without causing luminance inconsistency or visible defects like spots or lines.
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 effectively reduces the occurrence of image quality defects like spots and lines by ensuring consistent luminance across pixels, improving the charging ratio and reducing the perception of such defects, even at high resolutions or speeds.
Implementation Method 1
a liquid crystal layer having dielectric anisotropy interposed therebetween. The pixel electrodes may be arranged in a matrix and connected to the switching elements to sequentially receive data voltages for each row of the matrix. The opposing electrode may be formed on the entire surface of the display panel to receive a common voltage Vcom. A desired image may be acquired by applying voltages to the pixel electrode and the opposing electrode. These voltages generate an electric field in the liquid crystal layer. The intensity of the electric field may control transmittance of light passing through the liquid crystal layer.
Data Source
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AI summary
A display device (1) includes a signal controller (600) and a data driver (500). The signal controller processes an input image signal (IDAT) to generate an output image signal (DAT). The signal controller processes the input image signal using a correction unit (610). The correction unit corrects the input image signal to a first gray scale value greater than the 0 gray scale value when the gray scale value of the input image signal is 0. The output image signal is based on the corrected input image signal. The data driver converts the output image signal into a data voltage to be applied to a display panel (300).