Micro LED Pad Layout for Stable Substrate Bonding
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Solution Overview
Problem
The challenge lies in stably mounting micro light emitting diodes to a mounting substrate, as the reduced size of the light emitting device increases electrical resistance and makes it difficult to secure and bond the pads effectively, leading to instability in electrical connections.
Innovation Solution
The solution involves a light emitting device design where at least one pad extends to the dielectric structure, securing a sufficient contact area, and the remaining pads are distributed to occupy a wider area, ensuring stable electrical bonding by using pads with varying widths and areas to maintain efficient electrical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting device is reduced to micro unit size, then the device size is minimized for advanced display applications, but the electrical resistance increases and pad bonding becomes difficult
Solution Approach 1:
The pad structure transitions from a two-dimensional planar configuration to a three-dimensional structure by extending vertically to the dielectric structure surface. This dimensional change increases the pad's contact area and bonding surface without increasing the horizontal footprint, thereby maintaining electrical connection reliability while preserving the micro unit size of the light emitting device.
Solution Approach 2:
The pad is designed to extend to the dielectric structure surface in advance, creating a pre-positioned bonding interface. This preliminary configuration ensures that when the device is mounted, the pad is already optimally positioned for electrical bonding, compensating for the difficulties of bonding at micro scales and ensuring connection stability before operation.
2Reliability
If the pad area is increased to reduce electrical resistance, then the electrical connection stability improves, but the device area increases
Solution Approach 1:
The pad utilizes the vertical dimension by extending to the dielectric structure surface, increasing its effective area for electrical bonding without expanding the horizontal device footprint. This allows the pad area to be increased for reduced electrical resistance while maintaining the compact device area required for micro unit applications.
Solution Approach 2:
The pad structure is differentiated locally by extending to the dielectric structure surface, creating a localized area increase at the bonding interface. This local quality change concentrates the area increase where it is most needed for electrical connection stability, while the rest of the device maintains its compact micro unit dimensions.
3Area of stationary object
If all pads are kept within the light emitting structure, then the device footprint is minimized, but the contact area for bonding is insufficient
Solution Approach 1:
The pad extends vertically to the dielectric structure surface, utilizing the third dimension to increase bonding contact area without increasing the horizontal device footprint. This dimensional transition resolves the contradiction between minimizing device footprint and providing sufficient bonding contact area for manufacturing precision.
Data Source
AI summary
A light emitting device including a light emitting structure including a plurality of light emitting parts, a dielectric structure disposed outside the light emitting structure, and a plurality of pads disposed on a first surface of the light emitting structure and electrically coupled with the light emitting parts, in which outer sidewalls of the pads are disposed inside an outer sidewall of the light emitting structure and an outer sidewall of the dielectric structure, at least one of the pads extends to a first surface of the dielectric structure, and the first surface of the dielectric structure is coplanar with the first surface of the light emitting structure.