Antireflection Layer Etching in COA Active Matrix Substrates
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Solution Overview
Problem
In liquid crystal display devices with a color filter on array (COA) structure, the etching of inorganic protection films during antireflection layer formation by dry etching can lead to steps at the edges of the second transparent electrode, causing light leakage due to liquid crystal alignment disorders, which degrades the optical characteristics of the device.
Innovation Solution
A method of manufacturing an active matrix substrate that includes forming thin film transistors, color filters, a first transparent electrode, an inorganic protection film, a second transparent conductive film, and antireflection layers with a metal layer and inorganic insulating layer, where the antireflection layers are formed on the second transparent electrode, and a third transparent electrode is patterned to contact the second transparent electrode, thereby suppressing the etching of the inorganic protection film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If antireflection layers are formed by dry etching, then the antireflection layers can be effectively formed on the second transparent electrode, but the inorganic protection film exposed out of the second transparent electrode is etched, forming steps that cause light leakage
Solution Approach 1:
An organic protection film is formed on the inorganic protection film before the dry etching process. This organic protection film serves as a protective layer that prevents the inorganic protection film from being etched during the antireflection layer formation, thereby avoiding step formation and maintaining film integrity.
Solution Approach 2:
The organic protection film acts as an intermediary layer between the inorganic protection film and the dry etching process. It mediates the interaction by being resistant to the dry etching conditions, thus protecting the underlying inorganic protection film from damage while allowing the antireflection layers to be formed on the second transparent electrode.
2Ease of manufacture
If the inorganic protection film is etched during dry etching, then steps are formed at the edges of the second transparent electrode, but this causes light leakage due to liquid crystal alignment disorder
Solution Approach 1:
The organic protection film is formed in advance on the inorganic protection film before the dry etching process. This preliminary protective layer prevents the inorganic protection film from being etched, thereby avoiding step formation and the subsequent liquid crystal alignment disorders that would degrade optical characteristics.
Solution Approach 2:
The organic protection film serves as a mediator that protects the inorganic protection film during the dry etching process. By introducing this intermediary layer, the harmful effect of etching on the inorganic protection film is eliminated, preventing steps that would cause light leakage and maintain reliable optical characteristics.
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 approach prevents the formation of steps in the inorganic protection film at the edges of the second transparent electrode, reducing light leakage and enhancing the optical performance of the liquid crystal display device by maintaining proper liquid crystal alignment.
Implementation Method 1
when the antireflection layers are formed by dry etching, the inorganic protection film exposed out of the second transparent electrode is etched
Data Source
AI summary
A method of manufacturing an active matrix substrate includes forming multiple thin film transistors corresponding to multiple subpixels on a substrate; forming color filters provided with colored layers having predetermined colors disposed on the multiple thin film transistors, respectively, and having contact holes for electrical connection to the multiple thin film transistors, respectively; forming a first transparent electrode by forming a first transparent conductive film above the color filters and patterning the first transparent conductive film; forming an inorganic protection film made of an inorganic insulating film on the first transparent electrode; forming a second transparent conductive film on the inorganic protection film; forming antireflection layers on the second transparent conductive film, each of the antireflection layers formed by layering a metal layer and an inorganic insulating layer and overlapping a boundary portion between the colored layers; and forming a second transparent electrode by patterning the second transparent conductive film.