Liquid Crystal Panel Drive Voltage Control for Tailing Suppression
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Solution Overview
Problem
Existing image display apparatuses using normally white type liquid crystal panels face issues with display failures such as the 'tailing phenomenon' due to light leakage, which cannot be adequately suppressed by limiting the upper signal level, leading to suboptimal brightness and display quality.
Innovation Solution
An image display apparatus that includes a liquid crystal panel, an input means for receiving an image signal, a detection means to calculate the proportion of pixels at different signal levels, and a correction means to adjust the lower limit of the drive voltage based on these proportions, ensuring appropriate suppression of display failures and maintaining optimal brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper limit of the signal level of the image signal is limited to suppress display failure, then display failure is suppressed, but the brightness of the display image darkens
Solution Approach 1:
The patent applies dynamics by making the upper limit of the signal level adjustable rather than fixed. The signal level limiter dynamically changes the upper limit based on the proportion of black-side pixels detected in the image histogram, allowing the system to adapt between suppressing display failure and maintaining brightness depending on the image content requirements
Solution Approach 2:
The patent changes the parameter of the upper signal level limit based on the detected proportion of black-side pixels. When the proportion is high, the upper limit is reduced to suppress display failure; when the proportion is low, the upper limit is increased to maintain brightness, thus resolving the contradiction through parameter adaptation
2Reliability
If the area of the black image is made larger to improve display failure suppression, then display failure is more effectively suppressed, but the overall brightness of the display image decreases
Solution Approach 1:
The patent implements feedback by detecting the actual proportion of black-side pixels in the image signal and using this information to adjust the upper signal level limit. This closed-loop approach allows the system to respond to the actual image content rather than relying on fixed assumptions, optimizing both display failure suppression and brightness preservation
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 display failures like the 'tailing phenomenon' while maximizing image brightness by dynamically adjusting the drive voltage based on the histogram of the image signal, ensuring better image quality across varying image compositions.
Implementation Method 1
When a drive voltage is applied to pixel electrode 101, a potential difference arises between pixel electrode 101 and common electrode 102, producing an electric field inside liquid crystal 103 for the potential difference. As the arrangement of molecules of liquid crystal 103 changes in accordance with this electric field
Implementation Method 2
Since the arrangement of molecules of liquid crystal 103 also changes depending on this electric field (which will be referred to hereinbelow as transversal electric field), alignment failure of the molecules of liquid crystal 103 deviating from the ideal arrangement conforming to the longitudinal electric field may occur
Data Source
AI summary
The present invention is aimed at appropriately suppressing display failure such as a tailing phenomenon and the like in a normally white type liquid crystal panel. A driver (3) supplies a drive voltage in conformity with an image signal received by an image signal processing circuit (1), to a liquid crystal panel (4). A histogram detector (5) detects a histogram representing the relationship between the signal level of the image signal received by the image signal processing circuit (1) and the number of pixels. A CPU (6) calculates, based on the histogram detected by the histogram detector (5), a first proportion of the number of pixels (on the white side) whose signal level is equal to or greater than a first defined value, to the total number of pixels of the histogram and a second proportion of the number of pixels (on the black side) whose signal level is equal to or smaller than a second defined value that is smaller than the first defined value, to the total number of pixels of the histogram. An amplifier (2) corrects the lower limit of the drive voltage that the driver (3) supplies to the liquid crystal panel (4) in accordance with the first proportion of white side pixels and second proportion of black side pixels calculated by CPU (6).