Pad Electrode Arcing Prevention via Organic Insulating Layer
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Solution Overview
Problem
The manufacturing process of organic light emitting display devices faces issues with arcing between the mask and the pad electrode, leading to defects due to the high current flowing along the pad electrode, which is not effectively addressed by existing encapsulation methods.
Innovation Solution
A display device design that includes a first substrate with a display area and a non-display area surrounded by a dam, where the pad electrode is located outside the dam, and an encapsulation film with a first inorganic film that covers the pad electrode, preventing arcing by acting as an insulating layer between the mask and the pad electrode during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask is arranged close to the pad electrode to prevent inorganic film formation on the pad area, then the pad electrode is exposed, but arcing occurs between the mask boundary surface and the pad electrode causing defects
Solution Approach 1:
An organic film is introduced as an intermediary layer between the inorganic film and the pad electrode. The organic film is formed first to cover the pad electrode, then the inorganic film is formed over the organic film. This intermediary organic film prevents direct contact between the inorganic film and pad electrode, eliminating the arcing problem while maintaining precise pad electrode exposure through subsequent etching processes.
Solution Approach 2:
The organic film is formed in advance before the inorganic film deposition. This preliminary action ensures that the pad electrode is already covered with an insulating organic layer before the inorganic film is deposited, preventing arcing from occurring during or after the inorganic film formation process.
2Reliability
If the inorganic film is entirely formed on the organic light emitting diode except the pad area, then oxygen and water protection is provided, but a mask must be used which increases manufacturing complexity
Solution Approach 1:
The function of protecting the pad electrode is extracted from the mask process and assigned to a dedicated organic film layer. Instead of using a mask to prevent inorganic film deposition on the pad area, the organic film is specifically formed to cover the pad electrode, and the inorganic film is then formed over the entire surface including the organic film on the pad area. This eliminates the need for mask alignment and reduces manufacturing complexity.
3Reliability
If the organic film is formed to cover the pad electrode, then arcing is prevented, but the organic film must be precisely patterned which increases manufacturing difficulty
Solution Approach 1:
The organic film is formed to cover not only the pad electrode but also a broader area that will be subsequently defined by etching. The initial organic film formation uses a simpler masking process with larger margins, and the precise pattern is achieved later through etching processes that define the final pad electrode exposure area. This separates the arcing prevention function from the precise patterning requirement.
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 solution prevents arcing and defects by ensuring the first inorganic film acts as an insulating layer, eliminating the need for a mask over the pad electrode and reducing manufacturing complexities and costs.
Implementation Method 1
an encapsulation film with a first inorganic film that covers the pad electrode, preventing arcing by acting as an insulating layer between the mask and the pad electrode during the manufacturing process
Data Source
AI summary
A display device includes a first substrate where a display area and a non-display are defined, wherein a plurality of pixels are arranged at the display area and the non-display area surrounds the display area; a dam surrounding the display area and arranged at the non-display area; an organic light emitting diode provided in the display area; an encapsulation film disposed on the organic light emitting diode; a buffer layer disposed on the encapsulation film; an insulating film disposed on the buffer layer; a pad area arranged outside the dam, wherein the buffer layer and the insulating film extend from the display area to the pad area; a link line disposed between the dam and the first substrate; and a routing line provided on the insulating layer between the display area and the pad area.