OLED Pad Electrode Inclined Surface Design
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Solution Overview
Problem
Organic light emitting diode display devices experience high contact resistance between side electrodes and pad electrodes due to the small exposed area of pad electrodes, which also limits adhesion characteristics with flexible circuit boards.
Innovation Solution
Inclined surfaces on the pad electrodes increase the contact area between side and pad electrodes, reducing contact resistance and improving adhesion by forming grooves on the lower substrate using a laser and removing the protruding portion to create a larger contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the protruding portion of the lower substrate is removed to reduce dead space, then the area of non-light emitting regions is reduced, but the exposed area of pad electrodes is reduced and contact resistance increases
Solution Approach 1:
The pad electrode is designed with an inclined portion that extends in the vertical dimension, transforming the contact interface from a single-plane horizontal contact to a multi-dimensional inclined surface contact. This allows the side electrode to contact the pad electrode along the inclined surface, significantly increasing the contact area while maintaining a compact horizontal footprint that reduces dead space.
Solution Approach 2:
The pad electrode incorporates a curved inclined surface instead of a flat horizontal surface. This curved geometry provides a larger surface area for contact with the side electrode, improving electrical connectivity while maintaining space efficiency. The inclined curved surface allows the side electrode to wrap around and contact the pad electrode over an extended area.
2Area of stationary object
If the exposed area of pad electrodes is reduced to minimize dead space, then the device size is optimized, but adhesion characteristics with flexible circuit boards deteriorate
Solution Approach 1:
The inclined portion of the pad electrode adds a vertical dimension to the contact interface, allowing the side electrode and flexible circuit board to adhere along the inclined surface. This multi-dimensional contact provides both mechanical interlocking and increased bonding area, significantly improving adhesion strength while maintaining a compact horizontal footprint.
Solution Approach 2:
The side electrode is designed to wrap around and contact the inclined portion of the pad electrode, creating a nested contact structure. The flexible circuit board then contacts the side electrode along this nested interface, providing multiple levels of mechanical interlocking and adhesion that enhance overall bonding strength without increasing the horizontal dead space area.
3Reliability
If the lower substrate protrudes beyond the upper substrate to accommodate pad electrodes, then electrical connectivity is improved, but the number of non-light emitting areas increases
Solution Approach 1:
The pad electrode is designed with an inclined portion that extends vertically, allowing electrical connectivity to be achieved within the same horizontal footprint as the upper substrate. The inclined surface provides the necessary contact area for the side electrode without requiring the lower substrate to protrude horizontally, thereby eliminating additional dead space while maintaining electrical connectivity.
Solution Approach 2:
The curved inclined surface of the pad electrode provides sufficient contact area for electrical connectivity within the horizontal boundaries of the upper substrate. This curved geometry maximizes the contact area within the available vertical space, eliminating the need for horizontal protrusion and reducing non-light emitting areas.
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 reduces contact resistance between side and pad electrodes and enhances adhesion characteristics, leading to improved electrical connectivity and mechanical stability in organic light emitting diode display devices.
Implementation Method 1
a groove is formed on the lower substrate by using a laser
Data Source
AI summary
A display device includes a first substrate having a display area and a peripheral area, the first substrate including a first inclined surface disposed at an outer portion of the peripheral area and being angled relative to the first substrate in the display area; a pixel structure disposed on the first substrate in the display area; a second substrate disposed on the pixel structure; a first electrode disposed on the first inclined surface and between the first substrate and the second substrate; and a second electrode disposed on sides of the first and second substrates, the second electrode being in contact with the first electrode.