Micro LED Cathode Extension Layout for Crack-Free Low-Capacitance Driving
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Solution Overview
Problem
In micro LED display devices, the process of connecting the cathode electrode to a low potential voltage results in stress concentration and potential cracks due to overlapping with signal wires, leading to increased resistance and parasitic capacitance.
Innovation Solution
The design involves removing the overlap area between the cathode electrode and signal wires to reduce parasitic capacitance and increasing the cathode electrode area without signal wires, with the cathode electrode extending outward to connect to a contact electrode, and using a second optical layer to cover and planarize the second electrode, preventing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cathode electrode is connected to a low potential voltage in the conventional overlapping structure, then the electrical connection is established, but stress concentration occurs causing cracks and increased resistance
Solution Approach 1:
The patent extracts the harmful overlapping region between the cathode electrode and signal wire, removing it to eliminate the source of stress concentration and parasitic capacitance. The cathode electrode is redesigned to extend outward to connect to a contact electrode without overlapping signal wires, directly resolving the reliability-strength contradiction.
Solution Approach 2:
The patent transitions from a planar overlapping connection to a three-dimensional extended structure. The cathode electrode extends outward in a new spatial dimension to connect with the contact electrode, avoiding the harmful two-dimensional overlap with signal wires while maintaining electrical connectivity.
2Use of energy by moving object
If the cathode electrode overlaps with signal wires, then the connection area is sufficient, but parasitic capacitance increases causing power loss
Solution Approach 1:
The patent removes the overlapping region between the cathode electrode and signal wire, extracting the source of parasitic capacitance. This elimination directly reduces unwanted capacitance effects and associated power consumption while maintaining the necessary electrical connection through the extended electrode structure.
Solution Approach 2:
The patent converts the potential harm of extended electrode structure into a benefit by designing the extension to avoid signal wire overlap. The extended structure that could potentially increase capacitance is instead configured to reduce parasitic capacitance, turning a possible disadvantage into an advantage for power efficiency.
3Loss of energy
If the cathode electrode area is increased to reduce resistance, then the resistance decreases, but the overlap with signal wires increases causing more parasitic capacitance
Solution Approach 1:
The patent applies local quality by differentiating the cathode electrode structure into distinct regions: an extended region that connects to the contact electrode without overlapping signal wires (reducing parasitic capacitance), and a functional region that maintains sufficient connection area (reducing resistance). Each region is optimized for its specific function.
Solution Approach 2:
The patent uses dimensional change to increase the effective connection area of the cathode electrode by extending it outward in a new spatial direction, away from the signal wire plane. This allows the electrode to achieve lower resistance through increased area without proportionally increasing overlap with signal wires, thereby reducing parasitic capacitance.
Data Source
AI summary
An embodiment discloses a display apparatus. The display apparatus includes a plurality of first electrodes and a contact electrode disposed on a substrate. The display apparatus includes a plurality of light-emitting elements disposed on the plurality of first electrodes. The display apparatus includes a first optical layer disposed between the plurality of light-emitting elements. The display apparatus includes a second electrode disposed on the plurality of light-emitting elements. The second electrode includes a first area disposed on the plurality of light-emitting elements and a second area extending outward from the first optical layer and electrically connected to the contact electrode. A plurality of signal wires connected to the plurality of first electrodes are provided, the second area of the second electrode comprises protruding portions extending to at least one of areas between the plurality of signal wires, and one of the protruding portions is connected to the contact electrode.