LCD Panel Scan Signal Timing Adjustment for Brightness Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Color sequential LCDs suffer from uneven brightness due to insufficient response speed of liquid crystal molecules, leading to reduced luminance in last row pixels compared to first row pixels, resulting in poor image quality.
Innovation Solution
A method for driving an LCD panel by sequentially providing scan signals with adjusted enabling times, using a compensation module to determine and adjust the enabling times of scan signals, ensuring uniform brightness across all row pixels by progressively reducing compensation time from last to first row pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If color sequential method is used to replace color filters with LED backlight source, then transmittance of each pixel is improved, but response speed of liquid crystal molecules becomes insufficient leading to uneven brightness
Solution Approach 1:
The patent applies dynamics by making the enabling time of scan signals variable rather than fixed. The enabling time is dynamically adjusted based on the row number, with earlier rows receiving longer enabling times and later rows receiving shorter enabling times. This dynamic adjustment compensates for the delayed response of liquid crystal molecules in later rows, ensuring uniform brightness across the display while maintaining the high transmittance benefits of the color sequential method.
2Productivity
If refresh rate is increased from 16.67ms to 5.56ms to support color sequential method, then color display capability is improved, but response speed requirement exceeds current liquid crystal molecule capability
Solution Approach 1:
The patent applies preliminary action by providing longer enabling times to earlier rows and progressively shorter enabling times to later rows. This preliminary timing adjustment ensures that liquid crystal molecules in all rows have sufficient time to respond before the next frame is displayed, allowing the system to operate at the higher 5.56ms refresh rate required for color sequential method without exceeding the response speed capabilities of current liquid crystal molecules.
3Device complexity
If same data signals are provided to each pixel, then data transmission simplicity is maintained, but luminance of last row pixels is reduced compared to first row pixels
Solution Approach 1:
The patent applies local quality by making the enabling time parameter row-dependent rather than uniform across all rows. While the data signals themselves remain the same for all pixels, the enabling time associated with each scan signal varies by row position. This local adjustment ensures that each row receives the appropriate amount of time for liquid crystal response, achieving uniform luminance across different rows while maintaining simple data transmission.
Data Source
AI summary
A method for driving an LCD panel and an LCD using the same are provided. The method includes following steps. Firstly, a number of scan signals are provided sequentially, and an enabling time of the scan signals excluding the last scan signal is adjusted according to a compensation time, so as to unfix the enabling time of these scan signals. Next, the scan signals having the unfixed enabling time are sequentially provided to an LCD panel, so as to turn on a number of row pixels of the LCD panel one by one. Thereby, the entire brightness of the LCD can be uniformed by applying the method disclosed in the present invention.


