Stepped Auxiliary Electrode for LED Self-Alignment
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Solution Overview
Problem
Miniaturized LED packages face challenges in self-alignment during mounting due to small electrodes, making high-density packaging difficult, as self-alignment effects are less likely to occur and misalignment correction is hard to achieve.
Innovation Solution
The LED package design includes an auxiliary electrode larger than the element electrode with a step that makes the lower face smaller than the upper face, positioned inside the phosphor layer, which facilitates self-alignment and position correction during mounting, allowing for increased mounting density without obstructing adjacent packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an auxiliary electrode is provided to achieve self-alignment effect, then position correction during mounting is improved, but the size of the LED package increases
Solution Approach 1:
The auxiliary electrode is designed with a stepped structure where the lower face is smaller than the upper face. The smaller lower face area allows the electrode to fit within the phosphor layer boundaries, while the larger upper face provides sufficient surface area for self-alignment during mounting. This local differentiation of electrode face areas resolves the contradiction between needing large area for alignment and small overall package size.
2Productivity
If the LED package is miniaturized to increase mounting density, then productivity is improved, but self-alignment effect deteriorates
Solution Approach 1:
The invention changes the geometric parameters of the auxiliary electrode by creating a stepped structure with different face areas. The upper face maintains sufficient size for self-alignment effect even in miniaturized packages, while the overall electrode size is constrained by the smaller lower face that fits within the phosphor layer. This parameter differentiation allows miniaturization while preserving self-alignment capability.
Data Source
AI summary
An LED package used in a light-emitting device is provided with a function of position correction in mounting by self-alignment, and mounting density of such LED packages is increased. The LED package includes an LED element including an element electrode on a bottom surface, a phosphor layer containing a phosphor and covering a top surface and a side surface of the LED element, and an auxiliary electrode having an upper face bonded to a lower face of the element electrode, wherein the auxiliary electrode is larger than the element electrode, the auxiliary electrode includes a step that makes a lower face smaller than the upper face, and an end portion of the auxiliary electrode on a side where the step is formed is located inside an outer peripheral side of the phosphor layer.