Photosensitive Insulating Layer for LCD Color Filter Patterning
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Solution Overview
Problem
The conventional manufacturing process for thin film transistor liquid crystal display (TFT-LCD) devices involves complex photographic steps, leading to reduced yield and increased manufacturing costs due to misalignment of the black matrix and color filter, which affects the aperture ratio and brightness of the LCD device.
Innovation Solution
The process simplifies the manufacturing by using a photosensitive insulating layer as a passivation layer or overcoat and employing ink-jet printing for the color filter layer, reducing the number of masks and photographic steps, allowing for simultaneous patterning of the insulating layer and color filter with positive or negative photoresists.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the black matrix is designed to be broader than the desired area to be blocked to completely inhibit light leakage, then light leakage is prevented, but the aperture ratio of the LCD device is reduced
Solution Approach 1:
The patent replaces the conventional mechanical alignment method (broad black matrix design) with a chemical/photochemical method (photosensitive insulating layer patterning). The photosensitive insulating layer is exposed and developed to form precise patterns that define the black matrix boundaries, eliminating the need for mechanical over-design and enabling accurate alignment between the black matrix and color filter.
2Area of moving object
If the conventional process with multiple photographic steps is used to prepare COA-TFT, then the aperture ratio is enhanced, but the complex photographic steps reduce the yield throughout
Solution Approach 1:
The patent merges multiple separate photographic steps into a single integrated process. The photosensitive insulating layer serves dual purposes: it acts as both the insulating layer and the patterning mask for the black matrix and color filter. By forming both layers simultaneously through one exposure and development process, the patent eliminates sequential photographic steps, reduces alignment errors, and improves manufacturing yield while maintaining the enhanced aperture ratio.
Solution Approach 2:
The photosensitive insulating layer performs multiple functions: it provides electrical insulation, serves as a patterning mask, and defines the boundaries of the black matrix and color filter regions. This multi-functional approach eliminates the need for separate mask layers and reduces the number of photographic steps required, thereby improving yield while maintaining the aperture ratio benefits of COA-TFT.
3Manufacturing precision
If multiple masks and photographic steps are used in the conventional manufacturing process, then precise patterning is achieved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the insulating layer formation and patterning mask functions into a single photosensitive insulating layer. This layer is applied once and patterned through a single exposure and development process to simultaneously define the black matrix and color filter regions, eliminating the need for multiple separate masks and photographic steps while maintaining precise patterning.
Solution Approach 2:
The photosensitive insulating layer serves as both the insulating layer and the patterning mask for multiple features (black matrix, color filter boundaries). This multi-functional approach reduces the total number of manufacturing steps and masks required, simplifying the manufacturing process while achieving the same patterning precision as the conventional multi-step approach.
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 reduces the number of photographic steps, enhances the aperture ratio, and improves the yield and stability of the TFT-LCD devices by simplifying the manufacturing process and maintaining excellent insulation and transmittance properties.
Implementation Method 1
the first insulating layer and the black matrix are both positive photoresists or negative photoresists... patterning the first photosensitive insulating layer and the black matrix
Implementation Method 2
employing ink-jet printing for the color filter layer
Implementation Method 3
a first metal layer 102 is first formed on a substrate 101 by sputtering
Implementation Method 4
SiNx or SiOx as a gate insulating layer 103, a-Si as a semiconductor layer 104, and n+Si as an ohmic contact layer 105 are formed by PECVD
Implementation Method 5
the ohmic contact layer 105 is etched to form a through hole by dry etching
Implementation Method 6
SiNx or SiOx as a passivation layer 107 is formed by chemical vapor deposition
Data Source
AI summary
A method for manufacturing a lower substrate of a liquid crystal display device is disclosed and more particularly, a method for manufacturing a color filter layer on a lower substrate is disclosed. This method is achieved by using a photosensitive insulating layer as a passivation layer or an overcoat of a thin film transistor to reduce the number of masks, or of photographic steps. The photosensitive insulating layer used in the method has the characteristics of both photoresist and passivation layers so as to protect a thin film transistor from moisture and oxygen. In addition, the number of masks, or of photographic steps used in this method can be further reduced by ink-jet printing a color filter layer or by half-tone mask technique.