Bezel Substrate Wiring for Display Panel Stress Management
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Solution Overview
Problem
In chip-on-film encapsulation for display panels, strong rebound stress at the bending section leads to peeling of bezel substrates from the display panel and breakage of metal wirings, exacerbated by thermal deformation due to high temperatures and large expansion coefficients of flexible circuit boards, which complicates bonding processes.
Innovation Solution
The implementation of a bezel substrate with a bending section featuring intersecting wirings of varying widths and staggered openings, which reduce stress concentration, alleviate bending stresses, and suppress crack propagation, while also decreasing the area of the bending section to prevent peeling and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the chip-on-film encapsulation is bent to mount at the bottom of the display panel, then the screen-to-body ratio is improved, but the flexible circuit board peels off from the display panel due to rebound stress
Solution Approach 1:
The patent introduces a bending section that segments the flexible circuit board into distinct functional areas: a rigid mounting area at the display panel and a flexible bending area extending to the bottom. This segmentation allows the bending section to absorb rebound stress through controlled deformation, preventing stress transmission to the bonding interface and eliminating peeling while maintaining narrow bezel design
Solution Approach 2:
The patent modifies the physical parameters of the flexible circuit board by creating a bending section with specific geometric characteristics (reduced thickness, modified wiring layout with varying widths, and staggered openings). These parameter changes enable the bending section to undergo elastic deformation during bending, absorbing rebound energy and maintaining bonding reliability despite the narrow bezel configuration
2Area of stationary object
If the flexible circuit board is bent for mounting, then the screen-to-body ratio is improved, but metal wirings breakage occurs due to stress concentration
Solution Approach 1:
The patent applies local quality by varying the wiring width within the bending section - the wiring is wider at certain locations and narrower at others. This non-uniform width distribution creates stress relief zones that prevent stress concentration, allowing the wirings to withstand repeated bending cycles without breakage while maintaining the narrow bezel design
Solution Approach 2:
The patent introduces staggered openings in the bending section that create a three-dimensional stress distribution pattern. These openings interrupt the continuous stress path, forcing stress to distribute across multiple dimensions and pathways, thereby preventing localized stress concentration that would lead to wiring breakage during bending
3Ease of manufacture
If chip-on-film encapsulation is performed at high temperature, then the bonding process is completed, but the flexible circuit board deforms due to large expansion coefficient
Solution Approach 1:
The bending section acts as a segmentation that isolates the high-temperature bonding process from the rest of the flexible circuit board. During bonding, the bending section can undergo thermal expansion and contraction independently, absorbing dimensional changes and preventing deformation of the mounted chip and display panel while still allowing complete bonding process execution
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 design effectively prevents wiring breakage, reduces peeling of the flexible circuit board from the display panel, ensures display quality, and increases the reliability and durability of the flexible circuit board by managing thermal deformation and bonding requirements.
Implementation Method 1
When the bezel substrate of a flexible circuit board is bent, the openings are subjected to a tensile force and are enlarged to alleviate stresses received by the bending section and reduce an extrusion force of the wirings
Implementation Method 2
a temperature used in the chip-on-film encapsulation is high but a flexible circuit board has a greater expansion coefficient which causes the flexible circuit board susceptible to thermal deformation
Data Source
AI summary
A display panel and a bezel substrate thereof are disclosed. The bezel substrate includes a bending section and a plurality of wirings. Each of the wirings includes a first line section and a second line section, the first line section and the second line section are disposed on the bending section, a width of the first line section to each of the wirings is greater than a width of the second line section of the wirings, and the first line sections of the adjacent wirings are staggered with respect to each other.