Liquid Crystal Display Auxiliary Capacitance Stacked Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal display devices face challenges in maintaining a large auxiliary capacitance without reducing the aperture ratio or increasing the pixel area, and they are prone to short circuits between auxiliary capacitance electrodes due to the thickness differences in insulating films during manufacturing.
Innovation Solution
The solution involves forming a liquid crystal display device with a specific configuration of insulating films, where a second insulating film serves as a dielectric layer for auxiliary capacitance, and the first and third insulating films are structured to reduce exposure time to etching atmospheres, thereby minimizing damage to the upper auxiliary capacitance electrode and maintaining adequate thickness without increasing the auxiliary capacitance area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the auxiliary capacitance area is increased to maintain large auxiliary capacitance, then the auxiliary capacitance increases, but the aperture ratio of each pixel is reduced
Solution Approach 1:
The patent transitions from a planar auxiliary capacitance structure to a three-dimensional stacked structure by placing the upper auxiliary capacitance electrode above the lower auxiliary capacitance electrode through the second insulating film. This vertical stacking enables increased auxiliary capacitance within the same pixel area, thereby maintaining aperture ratio while achieving larger auxiliary capacitance.
Solution Approach 2:
The upper auxiliary capacitance electrode is positioned within the vertical space above the lower auxiliary capacitance electrode, creating a nested configuration. The second insulating film acts as a dielectric layer nesting the two electrode structures together, allowing the auxiliary capacitance to be formed in the vertical dimension rather than requiring additional horizontal space.
2Quantity of substance
If the gate insulating film is made thinner to increase auxiliary capacitance, then the auxiliary capacitance increases, but short circuits between gate electrode and scanning line occur
Solution Approach 1:
The gate insulating film is segmented into two distinct layers: the first insulating film (thicker, 3000-6000 Å) providing electrical isolation between the gate electrode and scanning line, and the second insulating film (thinner, 500-2000 Å) serving as dielectric for auxiliary capacitance. This segmentation allows each layer to be optimized for its specific function, preventing short circuits while maintaining auxiliary capacitance.
Solution Approach 2:
Different regions of the insulating film structure have different thicknesses and functions. The first insulating film has greater thickness in regions requiring electrical isolation (gate electrode and scanning line areas), while the second insulating film provides the necessary dielectric property for auxiliary capacitance where space is constrained. This local differentiation of quality resolves the contradiction between isolation and capacitance.
3Quantity of substance
If the insulating film thickness is reduced to increase auxiliary capacitance, then the auxiliary capacitance increases, but manufacturing precision is compromised due to etching damage
Solution Approach 1:
The first insulating film is formed first as a protective layer before forming the second insulating film. During subsequent etching processes to create contact holes, the first insulating film serves as a protective barrier that prevents etching damage to the underlying structures. This preliminary protective action enables the second insulating film to be formed with precise thickness control without suffering from etching damage.
Solution Approach 2:
The first insulating film acts as a cushioning protective layer before the formation of the second insulating film. During manufacturing processes, particularly etching operations, this pre-existing layer cushions and protects the thin second insulating film and underlying electrodes from direct exposure to etching atmospheres, thereby maintaining manufacturing precision and preventing damage.
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 allows for increased auxiliary capacitance while reducing the occurrence of short circuits and maintaining electrical isolation, thus enhancing the reliability and performance of the liquid crystal display device.
Implementation Method 1
a second insulating film 26 that serves as a dielectric layer for auxiliary capacitance
Implementation Method 2
When a voltage is applied to the electrode formed on the substrate, the liquid crystal molecules are re-oriented, and accordingly the transmittance of light is changed
Data Source
AI summary
An auxiliary capacitance line and a terminal portion of a liquid crystal display device are made of an Al or Al alloy layer and an Mo layer. The edge portions of a lower auxiliary capacitance electrode and the terminal portion are sequentially coated with a first insulating film, a second insulating film that is thinner than the first insulating film, and a third insulating film. The lower auxiliary capacitance electrode is coated with the second insulating film, and an upper auxiliary capacitance electrode is laid on the surface of the second insulating film on the lower auxiliary capacitance electrode.