Display Apparatus Gray Scale Correction for Parasitic Capacitance
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Solution Overview
Problem
Vertical shadows and gray scale inclination in liquid-crystal display apparatuses due to Csd parasitic capacitance between source lines and pixels degrade image quality.
Innovation Solution
A display apparatus with a control unit that corrects gray scale data for each pixel based on the integrated voltage applied to the source line over a frame period, using future or previous frame data to adjust for parasitic capacitance effects, thereby minimizing the impact of Csd parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If voltage driving of source lines is performed to suppress vertical shadow, then image quality is improved, but Csd parasitic capacitance causes gray scale inclination
Solution Approach 1:
The control unit performs preliminary calculation of integrated voltage values for source lines during the vertical blanking period, before the actual image display begins. This advance preparation allows the system to pre-determine correction amounts for each pixel based on future frame data, enabling the suppression of both vertical shadows and gray scale inclination to occur simultaneously without conflict
Solution Approach 2:
The system calculates integrated voltage values based on gray scale data from future frames (n+1), and uses this feedback information to adjust the voltage applied to source lines during the current frame (n). This feedback mechanism allows the system to compensate for the effects of Csd parasitic capacitance by anticipating and counteracting the voltage drops that would otherwise cause gray scale inclination
2Manufacturing precision
If gray scale data is corrected using integrated voltage values, then Csd parasitic capacitance effects are suppressed, but calculation complexity increases
Solution Approach 1:
The control unit performs preliminary calculation of integrated voltage values for source lines during the vertical blanking period, before the actual image display begins. This advance preparation allows the system to pre-determine correction amounts for each pixel based on future frame data, enabling the suppression of both vertical shadows and gray scale inclination to occur simultaneously without conflict
Solution Approach 2:
The system changes the parameter being controlled from simple voltage levels to integrated voltage values that account for the cumulative effect of Csd parasitic capacitance. By using integration of voltage over time as the correction parameter, the system can compensate for the capacitive effects that cause gray scale inclination, transforming the control parameter to one that inherently accounts for the parasitic capacitance
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
The solution effectively suppresses vertical shadows and gray scale inclination, improving image quality by accurately adjusting pixel voltages and compensating for capacitance-related issues.
Implementation Method 1
The vertical shadow is produced due to a Csd parasitic capacitance between a source line and a pixel in a display apparatus. The Csd parasitic capacitance also brings about problems such as gray scale inclination in a video displayed on the display apparatus.
Data Source
AI summary
A display apparatus comprises: pixels arranged in a matrix, gate lines, source lines, and a control unit. The gate lines are connected to pixels arranged in a row direction and select, in order, pixels in each row at a given frame period. The source lines supply a voltage according to a given gray scale to the pixels in the selected row. The control unit controls, based on gray scale data indicating gray scales included in one frame of video, a timing to cause the pixels in each row to display, in order, gray scales for one row in the video. The control unit corrects, with a target pixel as a reference, gray scale data indicating a gray scale to be displayed by the target pixel, based on an integrated value indicating an integration of voltage applied to a source line connected to the target pixel in one future frame.