Stretchable Display LED Layout That Eliminates Planarization
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Solution Overview
Problem
The fabrication process for stretchable display devices is complicated due to the planarization process required for vertical LED chips, and the connection of electrodes using anisotropic conductive film, leading to increased complexity and cost.
Innovation Solution
The anode and cathode of the light emitting diode chip are horizontally disposed and connected, simplifying the fabrication process and reducing thickness and cost by using a method that includes forming a thin film transistor on a substrate, forming electrodes, and connecting layers through expanding layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vertical LED chip is mounted with electrodes at upper and lower portions, then the LED chip can be connected to the display device, but a planarization process is required to mitigate step difference, complicating the fabrication process
Solution Approach 1:
The patent inverts the conventional vertical electrode arrangement of LED chips to a horizontal configuration. Instead of having electrodes at the upper and lower portions (vertical mounting), the electrodes are positioned at opposite sides of the LED chip in a horizontal arrangement. This inversion eliminates the need for planarization processes to mitigate step differences, as the horizontal electrode placement creates a flatter surface profile that integrates more seamlessly with the flexible display substrate.
2Reliability
If the first electrode is connected using anisotropic conductive film and the second electrode through planarization and photolithographic processes, then the LED chip can be connected, but the fabrication process becomes complicated
Solution Approach 1:
The patent merges the connection processes for both electrodes into a single horizontal mounting operation. By positioning both electrodes horizontally on the LED chip, they can be connected simultaneously using the same anisotropic conductive film application and photolithographic processes, rather than requiring separate vertical and horizontal connection steps. This consolidation reduces the number of fabrication steps while maintaining reliable electrical connections.
3Ease of manufacture
If a vertical LED chip is used with electrodes at upper and lower portions, then the LED chip can be mounted, but the device thickness increases
Solution Approach 1:
The patent transitions from a vertical (z-axis) electrode arrangement to a horizontal (x-y plane) arrangement. By placing electrodes at opposite sides of the LED chip in the horizontal plane rather than stacking them vertically, the overall device thickness is reduced. This dimensional reconfiguration allows the display device to maintain ease of mounting while achieving a thinner profile, which is critical for flexible and wearable display applications.
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 approach simplifies the fabrication process and reduces the thickness and cost of the stretchable display device by horizontally disposing the anode and cathode, optimizing the fabrication process.
Implementation Method 1
forming a second expanding layer by adding heat to the first expanding layer
Data Source
AI summary
A display device includes: a substrate; a thin film transistor on the substrate; a first electrode connected to the thin film transistor and a second electrode spaced apart from the first electrode; an adhesive layer between the first and second electrodes; a light emitting diode chip on the adhesive layer and including a junction layer, an anode and a cathode, the anode and the cathode on both sides of the junction layer; and a first connecting layer between the first electrode and the anode and a second connecting layer between the second electrode and the cathode, wherein the anode and the cathode are disposed horizontally.