Display Panel IC Mounting via FPC Buffer Layer
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Solution Overview
Problem
The chip-on-glass (COG) method for mounting driving integrated circuits (ICs) on display panels can cause damage to the panels due to applied pressure, which is not effectively minimized by existing technologies.
Innovation Solution
A display device design that includes a substrate with a display area, peripheral area, and pad area, featuring a testing circuit unit, cover layer, output pad, input pad, and protective layer, where the driving chip is mounted using conductive balls in an adhesive insulation resin layer, and the protective layer is positioned apart from the cover layer to reduce stress concentration and potential damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the driving IC is mounted using the COG method with direct heating and pressing, then the mounting process is simple and efficient, but the display panel may be damaged due to applied pressure
Solution Approach 1:
The mounting process is divided into two separate operations: first, the driving IC is mounted on the FPC using the COG method; second, the FPC with the mounted IC is then mounted on the display panel. This segmentation allows the pressing force to be applied to the FPC rather than directly to the display panel, resolving the contradiction between mounting efficiency and panel integrity.
Solution Approach 2:
The FPC serves as an intermediary component between the driving IC and the display panel. By mounting the IC on the FPC first and then attaching the FPC to the panel, the FPC acts as a buffer that protects the display panel from direct pressing forces during the COG mounting process, while still allowing efficient IC mounting.
2Device complexity
If the driving IC is directly mounted on the display panel using COG method, then the structure is simple, but pressure is applied to the display panel causing potential damage
Solution Approach 1:
The mounting structure is segmented into three components: the display panel, the FPC, and the driving IC. The IC is mounted on the FPC separately, and the FPC is then mounted on the panel. This segmentation reduces the complexity of protecting the panel during IC mounting, as the FPC naturally serves as a protective buffer.
Solution Approach 2:
The FPC is introduced as an intermediary layer between the driving IC and the display panel. This intermediary structure simplifies the overall mounting process by eliminating the need for complex protective measures, as the FPC itself protects the panel from pressing forces during IC mounting.
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 minimizes or reduces the occurrence of damage to the display panel during the mounting of the driving IC, ensuring the panel's integrity and extending its lifespan.
Implementation Method 1
an adhesive insulation resin layer in which conductive balls are dispersed, and disposed between the pad area and the driving chip, and by using the conductive balls, the input bump is electrically connected to the input pad, and the output bump is electrically connected to the output pad
Data Source
AI summary
A display device includes a substrate including a display area, a peripheral area outside the display area, and a pad area within the peripheral area; a testing circuit unit disposed within the pad area; a cover layer covering the testing circuit unit; an output pad disposed within the pad area and arranged between the testing circuit unit and the display area; an input pad disposed within the pad area, disposed at an opposite side with respect to the plurality of output pads; and a protective layer covering the output pad and the input pad, and, on a plane, an end of the protective layer is apart from the cover layer.