Electrooptic Apparatus Film Uniformity via Segmented Partition
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Solution Overview
Problem
Existing film forming methods result in a concentration gradient that causes solvents to move from the central area to the peripheral area of a pattern, leading to uneven film thickness, which can cause display failures in electrooptic apparatuses like liquid crystal devices, reducing their display quality.
Innovation Solution
A film forming method involving the creation of a frame-shaped partition within the application area, where the partition's side surface is closer to the center than the outer edge, and its height is initially smaller than the applied material liquid's thickness but becomes equal as it dries, preventing solvent migration by separating the central and peripheral areas, thus maintaining uniform film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a solution is applied to a substrate without a partition, then the application process is simple, but the peripheral area of the pattern becomes thicker than the central area due to solvent migration
Solution Approach 1:
The application area is divided into a central area and a peripheral area by introducing a frame-shaped partition. This segmentation prevents solvent migration from the central area to the peripheral area, thereby maintaining uniform film thickness across different regions while keeping the partition structure relatively simple.
Solution Approach 2:
The frame-shaped partition acts as an intermediary structure between the central and peripheral areas. It physically blocks the solvent migration path, preventing the harmful effect of solvent movement while allowing the material liquid to be applied uniformly across the substrate.
2Quantity of substance
If the peripheral area is dried more than the central area, then the concentration gradient increases, but this causes solvent to move from the central area to the peripheral area, making the peripheral film thicker
Solution Approach 1:
By segmenting the application area into central and peripheral regions using a frame-shaped partition, the patent prevents the harmful interaction between concentration gradient and solvent migration. The partition isolates these regions, allowing controlled drying without unwanted solvent movement that would cause thickness non-uniformity.
3Ease of operation
If no partition is formed, then the drying process is uniform, but the peripheral area still becomes thicker due to natural solvent migration toward the edge
Solution Approach 1:
The frame-shaped partition serves as an intermediary barrier that selectively blocks solvent migration paths. It allows the drying process to proceed naturally while preventing the harmful solvent movement from central to peripheral areas, thus maintaining both operational simplicity and film thickness uniformity.
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 method ensures a flat film with uniform thickness, improving the display quality of electrooptic apparatuses by preventing excessive thickness at the peripheral areas and maintaining the flatness of the film during the drying process.
Implementation Method 1
forming a frame-shaped partition in the application area, the partition having a side surface facing a center of the application area... the partition is formed so that a distance between the side surface of the partition and the center is smaller than a distance between an outer edge of the application area and the center
Implementation Method 2
drying the applied material liquid... (c) drying the material liquid
Data Source
AI summary
An electrooptic apparatus includes an electrooptic material interposed between a pair of substrates, and a film formed above each of surfaces of the substrates facing the electrooptic material. The film is formed by a method including (a) forming a frame-shaped partition in an application area on the substrate, the partition having a side surface facing a center of the application area, (b) applying the material liquid to the application area, and (c) drying the material liquid. In step (a), the partition is formed so that a distance between the side surface of the partition and the center is smaller than a distance between an outer edge of the application area and the center, and so that a height of the partition is smaller than a film thickness of the material liquid at a time when the material liquid is applied and is larger than a thickness of the dried film.