Active Matrix Display Electrode Layout for Current Leak Prevention
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with current leak due to exposed parts of the organic insulating film, leading to deteriorated display image quality, especially when operated in high humidity or over long periods, caused by the faster etching rate of inorganic insulating films relative to organic insulating films, resulting in retraction of inorganic film edges and potential short circuits.
Innovation Solution
The design includes a structure where the distance between the electrode layer and the second contact hole is larger than the distance between the electrode layer and the first contact hole, preventing the formation of exposed organic insulating film parts, thereby reducing current leaks and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inorganic insulating film is formed at a lower temperature than the organic insulating film, then the film formation process is feasible, but the inorganic insulating film becomes less dense and exhibits faster etching rate
Solution Approach 1:
The patent changes the formation temperature parameter of the inorganic insulating film to be higher than or equal to that of the organic insulating film. This parameter change increases the density of the inorganic insulating film and reduces its etching rate, thereby achieving uniform etching rates between the two films and preventing edge retraction.
2Measurement precision
If the pixel size is reduced to increase resolution, then the display resolution is improved, but the distance between contact holes decreases causing inorganic insulating film edge retraction
Solution Approach 1:
By changing the formation temperature parameter of the inorganic insulating film, the patent achieves uniform etching rates that prevent edge retraction even when pixel sizes are reduced and contact holes are positioned closer together, thereby maintaining insulating film integrity in high-resolution displays.
3Productivity
If the inorganic insulating film has faster etching rate, then the etching process is more efficient, but the film edge retracts from the organic insulating film edge causing exposed parts
Solution Approach 1:
The patent adjusts the formation temperature parameter of the inorganic insulating film to match or exceed that of the organic insulating film, which slows down its etching rate to be uniform with the organic film. This prevents edge retraction and maintains precise film edge alignment while preserving etching efficiency.
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 prevents current leaks and maintains image quality by ensuring no exposed parts of the organic insulating film, even in high humidity environments or during extended use, as demonstrated by reduced leak current over time in Embodiment 1.
Implementation Method 1
when the inorganic insulating film 114 and the insulating film 110 are processed by dry etching
Implementation Method 2
displays images by generating an electric field parallel to a substrate between a pixel electrode and a counter electrode
Implementation Method 3
by driving liquid crystal with the electric field, so as to modulate light passing through the liquid crystal
Data Source
AI summary
Provided is a technology for preventing current leak of a charge holding capacitor which constitutes a pixel of a display device so as to prevent deterioration of display image quality of the display device. The display device includes a first contact hole connecting a first wiring layer and a second wiring layer which is formed over the first wiring layer, a second contact hole connecting the second wiring layer and a third wiring layer which is formed over the second wiring layer, and an electrode layer formed between the plurality of insulating films disposed between the second wiring layer and the third wiring layer, wherein at a position in a substrate surface direction, a distance between a electrode layer and the second contact hole is larger than a distance between the electrode layer and the first contact hole.