Micro LED Assembly With Localized Conductive Balls for Reliable Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices using micro LEDs face challenges in precise assembly and electrical connection, leading to issues such as incomplete electrical connections and short circuits due to the use of conductive balls.
Innovation Solution
A method for directly transferring micro LEDs grown on a growth substrate to a thin film transistor substrate, using a conductive adhesive layer to localize conductive balls between the LED electrodes, thereby avoiding the problems associated with conventional conductive ball placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive balls are used to electrically connect light emitting devices to the thin film transistor substrate, then electrical connection is achieved, but the adhesive layer flows in peripheral directions causing circuit open or short circuit
Solution Approach 1:
The conductive balls are positioned on the adhesive layer before the bonding process. This preliminary positioning ensures that the conductive balls are already in place before the adhesive layer is subjected to bonding pressure, preventing them from being displaced by the pressure and avoiding circuit open or short circuit issues.
Solution Approach 2:
The adhesive layer serves as an intermediary medium between the light emitting devices and the thin film transistor substrate. By positioning conductive balls on this intermediary layer before bonding, the system achieves both electrical connection and precise positioning without the harmful effects of adhesive flow during the bonding process.
2Reliability
If bonding pressure is applied to electrically connect conductive balls between electrodes, then electrical connection is achieved, but the adhesive layer flows causing light emitting devices to not be electrically connected
Solution Approach 1:
The conductive balls are positioned on the adhesive layer before bonding pressure is applied. This preliminary action ensures that when bonding pressure is applied to achieve electrical connection, the conductive balls remain in their designated positions and are not displaced by the adhesive flow, thereby maintaining high yield of electrically connected devices.
3Reliability
If the number of conductive balls is increased to improve electrical connection, then electrical connection reliability improves, but short circuit between electrodes occurs
Solution Approach 1:
The conductive balls are positioned on the adhesive layer before bonding, allowing for precise control of their number and distribution. This preliminary positioning enables using the minimum necessary number of conductive balls to achieve reliable electrical connection without excessive balls that could cause short circuits between electrodes.
Solution Approach 2:
The conductive balls are positioned at specific locations on the adhesive layer corresponding to the electrode positions. This localized positioning ensures that conductive balls are present only where electrical connection is needed, avoiding short circuits in areas where electrodes should remain isolated.
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 enables reliable and precise electrical connections between micro LEDs and the thin film transistor substrate, improving the reliability, precision, and mass productivity of micro LED display devices, and allowing for the creation of high-resolution and flexible display devices.
Implementation Method 1
using a conductive adhesive layer to localize conductive balls between the LED electrodes
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5a
AI summary
The present disclosure is applicable to a display device-related technical field, for example, relates to a display device using a micro LED (light emitting diode) and a method for manufacturing the same. A display device using a light emitting device includes a plurality of anode electrodes partitioned, a plurality of cathode electrodes positioned on one side of the anode electrodes, and a plurality of light emitting device assemblies electrically connected to the anode and cathode electrodes to configure individual sub-pixels. The light emitting device assembly may include a light emitting device, a first electrode disposed on the light emitting device and electrically connected to the anode electrode through conductive balls, a second electrode disposed on the light emitting device and electrically connected to the cathode electrode by conductive balls, first adhesive layers disposed on the first electrode and the second electrode to be spaced apart from each other, and a second non-conductive adhesive layer positioned on the first adhesive layer.