Display Pad Insulating Structure Against Etching-Induced Short Circuits
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Solution Overview
Problem
Existing electronic apparatuses face failures due to chemical reactions between signal lines and etching solutions during the fabrication process, leading to short circuits and pad deterioration, which affects the reliability and efficiency of the display and input sensing units.
Innovation Solution
The electronic apparatus is designed with a specific structure where the insulating layers between the signal lines and pads have a maximum thickness greater than the sum of the individual insulating layers, preventing exposure of the signal lines and reducing the risk of chemical reactions and pad failures by covering the signal lines until the fabrication of the display unit is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the insulating layers are made thin to reduce device thickness, then the device becomes more compact, but the signal lines become exposed to etching solutions causing chemical reactions and pad failures
Solution Approach 1:
The patent applies preliminary action by forming a protective insulating layer structure before the etching process. The pad insulating layer is formed with a maximum thickness greater than the sum of thicknesses of the first and second insulating layers, ensuring that signal lines remain covered throughout the fabrication process. This preliminary protective measure prevents chemical reactions between etching solutions and signal lines, thereby preventing pad failures while maintaining the desired device thickness.
2Reliability
If the insulating layers are made thick to protect signal lines from etching solutions, then pad reliability improves, but the device thickness increases
Solution Approach 1:
The patent applies local quality by differentiating the thickness of insulating layers in different regions of the device. The pad insulating layer is specifically designed with a maximum thickness greater than the sum of thicknesses of the first and second insulating layers, providing enhanced protection only where needed (in the pad region). This localized approach ensures signal line protection and pad reliability without uniformly increasing the overall device thickness.
3Productivity
If the signal lines are exposed during fabrication to enable proper connection, then assembly efficiency improves, but chemical reactions occur causing short circuits and pad deterioration
Solution Approach 1:
The patent applies the intermediary principle by introducing a pad insulating layer as a protective mediator between the signal lines and the etching environment. This intermediate layer prevents direct contact between etching solutions and signal lines, thereby preventing chemical reactions, short circuits, and pad deterioration. The intermediary layer allows the fabrication process to proceed efficiently without exposing signal lines to harmful chemicals.
4Reliability
If the pad insulating layer thickness is increased to prevent chemical reactions, then pad failure rate decreases, but manufacturing complexity increases
Solution Approach 1:
The patent applies partial or excessive action by providing the pad insulating layer with a maximum thickness that is greater than the sum of thicknesses of the first and second insulating layers. This excessive thickness ensures complete coverage and protection of signal lines in the pad region, preventing any potential chemical reactions or exposure. The design prioritizes reliability by ensuring sufficient protection margin, accepting the resulting increase in manufacturing complexity as a necessary trade-off for preventing pad failures.
Data Source
AI summary
An electronic apparatus includes a display unit and an input sensing unit. The display unit includes insulating layers, a signal line, a pad connected to an end portion of the signal line, and circuit elements. The insulating layers include a first insulating layer covering the circuit elements and exposing at least a portion of the circuit elements. The input sensing unit includes a first conductive layer, a second conductive layer including sensing patterns, and a second insulating layer between the first conductive layer and the second conductive layer. The second insulating layer exposes at least a portion of the first conductive layer. An insulating layer between the end portion of the signal line and the pad is defined as a pad insulating layer. A maximum thickness of the pad insulating layer is greater than a sum of thicknesses of the first and second insulating layers.