COF Corrosion Prevention via Flexible Coating
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Solution Overview
Problem
Existing display devices with chip on film (COF) technology face corrosion issues in the bending areas, which can lead to connectivity problems and device failure due to moisture and oxygen infiltration.
Innovation Solution
A display device design that incorporates an anisotropic conductive film between the COF and the display panel, along with a coating layer covering the bending area and one end of the COF, to prevent corrosion by isolating the second lines of the COF from external moisture and oxygen, while also ensuring secure attachment and flexibility during bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chip on film (COF) is used to drive the display device, then the device can be operated with signal connection, but the lines of the COF are prone to corrosion due to moisture and oxygen infiltration, especially in bending areas
Solution Approach 1:
The patent applies a bending protection layer (thin film) over the COF lines to create a protective barrier against moisture and oxygen infiltration. This flexible protective shell allows the COF to bend while preventing harmful environmental factors from reaching and corroding the conductive lines, thus resolving the contradiction between maintaining connectivity and preventing corrosion.
Solution Approach 2:
The bending protection layer creates an inert protective environment over the COF lines, isolating them from reactive moisture and oxygen in the external environment. This protective barrier effectively establishes a controlled, non-corrosive atmosphere around the vulnerable conductive lines, preventing oxidation and corrosion while allowing flexible movement.
2Adaptability or versatility
If the display panel is made flexible to allow bending, then the device can be adapted to various forms, but the COF lines in bending areas become vulnerable to corrosion and connectivity failure
Solution Approach 1:
The bending protection layer is designed as a flexible thin film that can accommodate the bending motion of the display panel while maintaining its protective function. This flexible protective shell moves with the COF during bending, preventing mechanical stress from exposing the lines to corrosion while preserving the device's adaptability to various forms.
Solution Approach 2:
The bending protection layer is applied in advance over the COF lines before the device undergoes bending operations. This protective layer cushions and protects the vulnerable lines from environmental exposure during bending, preventing corrosion before it can occur while allowing the device to achieve its desired flexible forms.
3Device complexity
If the COF is exposed to allow access and simplicity in structure, then the device structure remains simple, but the lines are directly exposed to moisture and oxygen causing corrosion
Solution Approach 1:
The bending protection layer adds a thin protective film over the COF lines, creating a barrier against moisture and oxygen while maintaining relatively simple device structure. This thin film protection does not significantly increase device complexity but effectively prevents direct exposure of the lines to harmful environmental factors.
Solution Approach 2:
The bending protection layer creates an inert protective environment over the COF lines, isolating them from reactive moisture and oxygen. This protective barrier maintains structural simplicity while establishing a controlled, non-corrosive atmosphere around the conductive lines, preventing oxidation and corrosion.
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
The solution effectively prevents corrosion of the COF lines, maintains connectivity, and allows for flexible bending without compromising the integrity of the display device, thereby enhancing its durability and reliability.
Implementation Method 1
an anisotropic conductive film provided between the chip on film and the display panel connecting the first lines and the second lines
Implementation Method 2
a coating layer covering the bending area and one end of the chip on film... to prevent corrosion by isolating the second lines of the COF from external moisture and oxygen
Data Source
AI summary
A display device including a display panel including a substrate, pixels provided on the substrate, and first lines connected to the pixels, the display device having a bending area where the display panel is bent. The display panel also includes a chip on film overlapping with a portion of the display panel and having second lines, an anisotropic conductive film provided between the chip on film and the display panel connecting the first lines and the second lines, and a coating layer covering the bending area and one end of the chip on film. In such a device, lines of the chip on film may be prevented from being corroded as they may be spaced apart from an edge of an insulating film.