Display Device Scanning Line Pulse Period Adjustment
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Solution Overview
Problem
Display devices with plural pixel circuits face uneven brightness due to differences in characteristics between pixel circuits, particularly in liquid crystal display devices using N-line inversion, where parasitic capacitance affects the voltage applied to liquid crystals, leading to inconsistent image quality.
Innovation Solution
A display device configuration that includes plural pixel groups with scanning lines, a clock signal supply circuit, and a shift register circuit, where the clock signal period is adjusted to accommodate variations in data signal polarity and transistor characteristics, ensuring consistent data signal transmission across pixel groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If N-line inversion is used to change polarity of data signal, then ghost image prevention is improved, but brightness unevenness occurs due to parasitic capacitance effects
Solution Approach 1:
The patent applies preliminary action by extending the pulse signal period for certain scanning lines before the polarity change occurs. This allows the pixel circuits to prepare for the upcoming polarity switch by ensuring adequate voltage establishment time, thereby preventing brightness unevenness while maintaining ghost image prevention through N-line inversion.
Solution Approach 2:
The patent implements dynamics by making the pulse signal period variable rather than constant. Different scanning lines receive different pulse periods dynamically adjusted based on their position and polarity change requirements. This dynamic adjustment compensates for parasitic capacitance effects and ensures uniform brightness across all pixel circuits.
2Device complexity
If uniform pulse signal period is used for all scanning lines, then device complexity is reduced, but brightness unevenness occurs due to characteristic differences between pixel circuits
Solution Approach 1:
The patent applies local quality by assigning different pulse signal periods to different scanning lines based on their specific requirements. Instead of a uniform approach, each scanning line receives a customized pulse period that accounts for local characteristic differences, thereby achieving brightness uniformity without significantly increasing overall device complexity.
3Illumination intensity
If pulse signal period is extended for certain scanning lines, then brightness uniformity is improved, but scanning time increases
Solution Approach 1:
The patent applies partial action by extending the pulse signal period only for specific scanning lines that require additional time due to polarity changes, rather than extending it for all lines. This selective approach achieves brightness uniformity where needed while minimizing the overall impact on scanning time and maintaining efficient operation for other 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 configuration effectively reduces brightness unevenness by synchronizing pulse signal periods and transistor operation, enhancing image quality by maintaining consistent voltage application to liquid crystals across all pixel groups.
Implementation Method 1
it takes a predetermined time for the potential of the pixel electrodes to vary to the potential of the data signal due to parasitic capacitance generated in the data signal lines and the like
Data Source
AI summary
A display device includes: plural pixel groups each including pixel circuits; plural scanning lines that are each connected to the pixel circuits included in any one of the pixel groups; a clock signal supply circuit that supplies a clock signal including a pulse signal; a shift register circuit that selectively transmits the pulse signal to the scanning lines in a predetermined order; and data signal lines that are connected to the pixel circuits and that supply a data signal to the pixel circuits included in the pixel group to be scanned. The period of the pulse signal supplied to some of the scanning lines is longer than the period of the pulse signal supplied to the other scanning lines, or the data signal is transmitted by the transistors included in the pixel circuits.