Cantilever Electrode LED for Reliable Group Transfer
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Solution Overview
Problem
Small-sized LEDs used in display apparatuses for devices like smart watches and AR glasses are difficult to handle and transfer onto circuit boards due to their size, leading to electrical connection failures and reduced luminous area, which affects image quality.
Innovation Solution
The use of light emitting devices with cantilever electrodes having a fixed and free-standing edge, made of metal layers with different thermal expansion coefficients, allows for stable electrical connection and adherence to circuit boards, enabling safe transfer and increased pixel area without the need for individual LED replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small-sized LEDs are transferred in a group onto a circuit board, then productivity is improved, but reliability deteriorates due to electrical connection failures
Solution Approach 1:
The patent applies preliminary action by pre-forming cantilever electrodes with free-standing edges on the LED structure before transfer. These pre-configured electrodes are designed to automatically make contact with pads on the circuit board during the transfer process, ensuring electrical connection is established in advance rather than requiring post-transfer connection work. This preliminary preparation enables reliable group transfer of multiple LEDs simultaneously.
2Area of stationary object
If sub-pixels are arranged on a two-dimensional plane, then device area is reduced, but luminous area decreases leading to deteriorated brightness
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional two-dimensional planar arrangement of sub-pixels to a three-dimensional stacked configuration. Multiple LED stacks are arranged vertically, allowing the luminous area to extend in the vertical dimension while maintaining a compact horizontal footprint. This enables both reduced display area and maintained or enhanced pixel brightness simultaneously.
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 facilitates the reliable transfer and connection of small-sized LEDs in groups, enhancing image quality by maintaining electrical connectivity and increasing pixel area, thus improving brightness and reliability in display apparatuses.
Implementation Method 1
The cantilever electrode may include at least two metal layers having different thermal expansion coefficients from each other
Data Source
AI summary
A light emitting device including at least one LED stack, electrode pads disposed on the LED stack, and cantilever electrodes disposed on the electrode pads, respectively, in which each of the cantilever electrodes has a fixed edge that is fixed to one of the electrode pads and a free standing edge that is spaced apart from the one of the electrode pads.