Bonding Wire Routing Over Third LED for Stress Relief
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Solution Overview
Problem
In light-emitting devices, the reduction in space between elements makes it difficult to install bonding wires and increases the risk of wire breakage due to stress from expanding sealing resins.
Innovation Solution
A light-emitting device configuration where the bonding wire passes directly over a third light-emitting element placed between the first and second elements, with a horizontal distance from the bonding wire to the wire-bonding electrode being at least 1.75 times the wire's diameter, using Ag for the bonding wire, and incorporating a sealing material with fillers and phosphor particles to reduce stress and expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space between light-emitting elements is reduced for downsizing, then the device size is reduced, but the bonding wire installation becomes difficult and the wire may break due to stress from sealing resin expansion
Solution Approach 1:
The bonding wire is routed to pass directly over the third light-emitting element (20c) positioned between the first (20a) and second (20b) elements, utilizing the vertical dimension above the element array. This overhead routing path allows the wire to span across multiple elements without being constrained by the reduced horizontal spacing between adjacent elements, thereby maintaining wire integrity while enabling device downsizing.
2Length of moving object
If the bonding wire length is reduced due to narrowed spacing, then the device is more compact, but the wire installation becomes difficult and breakage risk increases
Solution Approach 1:
By routing the bonding wire overhead across the light-emitting elements rather than along the side edges, the wire path utilizes the vertical space above the element array. This dimensional change allows for adequate wire length to be maintained even when horizontal spacing between elements is reduced, facilitating easier wire installation and bonding while preventing wire breakage.
3Reliability
If Ag is used for the bonding wire, then conductivity and reflectance are improved, but the wire may be more susceptible to breakage from resin expansion stress
Solution Approach 1:
The third light-emitting element (20c) positioned between the first (20a) and second (20b) elements serves as an intermediary structure that the bonding wire passes over. This intermediary routing path allows the use of Ag bonding wire for improved electrical conductivity and light reflectance while the wire is supported and protected from direct stress by the element structure, reducing breakage risk from sealing resin expansion.
Data Source
AI summary
A light-emitting device includes a first light-emitting element, a second light-emitting element, a third light-emitting element placed between the first and second light-emitting elements, and a bonding wire passing directly over the third light-emitting element and connecting the first light-emitting element with the second light-emitting element.