Liquid Crystal Display Electrode Parasitic Capacitance Reduction
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Solution Overview
Problem
In liquid crystal display devices with transversely-lengthened picture element electrodes, there is an issue with increased parasitic capacitance between the picture element electrodes and scanning signal lines, leading to decreased aperture ratio and storage capacitance, which affects display quality and power consumption.
Innovation Solution
The implementation of storage capacitor lines along scanning signal lines that overlap picture element electrodes via an insulating film, acting as shielding conductors to reduce parasitic capacitance and maintain aperture ratio while forming storage capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If picture element electrodes are transversely lengthened to reduce the number of video signal lines and lower power consumption, then power consumption is reduced, but parasitic capacitance between picture element electrodes and scanning signal lines increases
Solution Approach 1:
A storage capacitor line is introduced as an intermediary element between the picture element electrode and the scanning signal line. This storage capacitor line acts as a shielding conductor that mediates the electric field interaction, reducing parasitic capacitance while maintaining the transverse lengthening configuration for lower power consumption
Solution Approach 2:
The storage capacitor line converts the potentially harmful parasitic capacitance into a beneficial storage capacitance. By positioning the storage capacitor line to overlap with the picture element electrode, the electric field that would otherwise create parasitic capacitance is redirected to form useful storage capacitance, thereby reducing harmful effects while maintaining functional benefits
2Object-generated harmful factors
If storage capacitor lines are added to reduce parasitic capacitance, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The storage capacitor line serves multiple functions simultaneously: it acts as a shielding conductor to reduce parasitic capacitance, forms storage capacitance to maintain voltage levels, and can be integrated with existing scanning signal line structures. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity
3Reliability
If picture element electrodes are vertically lengthened to display more natural video pictures, then display quality is improved, but the number of video signal lines increases and power consumption increases
Solution Approach 1:
Instead of vertically lengthening the picture element electrodes to improve display quality, the invention inverts the approach by transversely lengthening the electrodes. This inversion allows the use of fewer video signal lines (one instead of three), thereby significantly reducing power consumption while maintaining acceptable display quality through the storage capacitor line compensation
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 solution effectively reduces parasitic capacitance, maintains storage capacitance, and improves display quality by shielding electric fields and forming auxiliary capacitances, thus addressing the challenges of power consumption and display defects.
Implementation Method 1
storage capacitor lines 36...overlap the respective picture element electrodes 60 via an insulating film 70
Implementation Method 2
reduces parasitic capacitance generated between a picture element electrode 60 and a scanning signal line 32
Data Source
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AI summary
A liquid crystal display device in which lengths (d1 and d2) of respective picture element electrodes (60) in an extended direction of scanning signal lines (32) are longer than lengths (d3) of the respective picture element electrodes (60) in an extended direction of video signal lines (35) is arranged such that storage capacitor lines (36) are provided along the respective scanning signal lines (32) so as to overlap the respective picture element electrodes (60) via an insulating film (70) in plan view.