Liquid Crystal Panel Driving Device Brightness Uniformity
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Solution Overview
Problem
Conventional liquid crystal displays experience uneven brightness due to increased leakage current when polarity inversion occurs, leading to reduced display brightness and polarization issues.
Innovation Solution
A driving device and method for liquid crystal panels that includes a scanning driver and data driver, which apply scanning and data voltages to pixels in a matrix, with a gain module that amplifies data voltages along the scanning direction using the formula VO=Vi*(Y*U+X)pn, where Vi is the original data voltage, Vo is the amplified voltage, and (Y*U+X)pn is the amplification coefficient, adjusted based on the polarity inversion signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polarity inversion is applied to prevent liquid crystal polarization, then liquid crystal rotation capability is maintained, but TFT leakage current increases and display brightness becomes uneven
Solution Approach 1:
The patent applies different voltage compensation strategies to different regions of the display panel. Specifically, pixels in even-numbered columns receive amplified data voltages when polarity inversion occurs, while pixels in odd-numbered columns maintain normal voltage levels. This localized differentiation compensates for the leakage current effect that varies by column position, thereby maintaining brightness uniformity across the entire display while preserving liquid crystal rotation capability through polarity inversion.
2Stability of the object's composition
If data voltage is inverted from positive to negative polarity, then liquid crystal polarization is prevented, but voltage difference between source and gate electrode decreases causing increased TFT leakage current
Solution Approach 1:
The patent implements preliminary compensation by amplifying the data voltage before it is applied to pixels in even-numbered columns when polarity inversion occurs. This pre-amplification counteracts the expected leakage current loss, ensuring that sufficient voltage remains after leakage to maintain proper display brightness. The compensation factor is determined in advance based on the polarity inversion signal, proactively addressing the energy loss before it manifests as display degradation.
3Ease of operation
If row-by-row scanning is used for liquid crystal panel, then scanning is simplified, but time period of current leakage increases along scanning direction causing gradual brightness dimming
Solution Approach 1:
The patent introduces spatial variation in voltage compensation based on column position within the row-by-row scanning framework. Pixels in even-numbered columns receive amplified data voltages during polarity inversion, while odd-numbered columns maintain standard voltage levels. This localized compensation approach maintains the simplicity of row-by-row scanning while correcting the brightness dimming effect that accumulates along the scanning direction, as the compensation is applied selectively to specific column groups rather than requiring complex scanning sequence modifications.
Data Source
AI summary
A driving device for liquid crystal panel comprising: a scanning driver for applying a scanning voltage to pixels arranged as a matrix row by row; and a data driver for receiving an image data and a polarity inversion signal, obtaining original data voltages according to the image data, determining if amplifying the original data voltages along a scanning direction according to the polarity inversion signal, and providing the original data voltages or data voltage after being amplified to pixels. A driving method is also disclosed. When polarity inversion signal is inverted to a positive polarity from a negative polarity, the data voltages applied on the data line are gradually increased along a scanning direction. Accordingly, when the polarity inversion signal is inverted to a negative polarity from a positive polarity, the pixel which leaks current seriously is charged with a larger amount of charges, uneven display brightness is obviously decreased.