Side-View LED Mounting with Inverted T Land Patterns
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Solution Overview
Problem
Existing methods for mounting side-view type light-emitting devices on substrates face issues such as the Manhattan phenomenon due to solder contraction and insufficient mounting strength, particularly when through holes are cut in a semicircular shape, leading to positional misalignment and reduced bonding area.
Innovation Solution
A light source design featuring a substrate with oblong through holes, land patterns of inverted 'T' shape on the mounting substrate, and wall-shaped solder members connecting rear and side electrodes, which improves mounting strength and prevents positional misalignment by aligning the through hole shape with the narrow region of the land pattern and forming a stable wall-like solder structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solder is applied only onto the rear surface, then the light-emitting device can be mounted, but the light-emitting element becomes inclined due to solder contraction and the Manhattan phenomenon occurs
Solution Approach 1:
The patent divides the solder application into two distinct segments: solder applied to the rear surface connecting the rear electrode to the mounting substrate, and solder applied to the front surface connecting the front electrode to the mounting substrate. This segmentation ensures that both surfaces contribute to mounting strength, preventing the light-emitting element from inclining due to unilateral solder contraction.
2Manufacturing precision
If the through hole is formed by cutting the long side of the substrate, then positioning accuracy is improved, but the mounting land area becomes insufficient and mounting strength is reduced
Solution Approach 1:
The patent extends the mounting land pattern from a simple planar shape to a three-dimensional structure by forming protrusions that extend in the thickness direction of the mounting substrate. This dimensional extension increases the mounting land area and volume without altering the through hole positioning, thereby simultaneously achieving precise positioning and sufficient mounting strength.
Solution Approach 2:
The mounting land pattern is constructed as a composite structure combining the mounting substrate material with solder material. The protrusions create a composite joint where the solder fills the space between the light-emitting device electrodes and the mounting substrate, forming a robust composite connection that enhances mounting strength while maintaining positioning accuracy.
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
The solution enhances the mounting strength of side-view type light-emitting devices by 50% and prevents the Manhattan phenomenon, ensuring accurate alignment and secure bonding, thereby improving the reliability of the light source for applications like liquid crystal display backlights.
Implementation Method 1
solder members are formed in a wall shape on the mounting substrate, are formed in the through holes on the mounting substrate, and connects the rear electrode and the side electrode to the wide region and the narrow region, respectively
Implementation Method 2
melting the solder member through heat treatment such that the solder member is formed in a wall shape on the mounting substrate
Implementation Method 3
an oblong flip chip type light-emitting element provided on the front surface of the substrate and connected to the front electrode
Implementation Method 4
side-view type light-emitting device, mounted on the mounting substrate, the light-emitting device including... an oblong flip chip type light-emitting element
Data Source
AI summary
A light source includes: a mounting substrate; and a side-view type light-emitting device including: a substrate; through holes; a front electrode; a rear electrode; side electrodes; and a light-emitting element, wherein: land patterns are formed on a front surface of the mounting substrate, in positions corresponding to the through holes, each land pattern having an inverted âTâ shape composed of a narrow region and a wide region; the light-emitting device is arranged such that the cross sectional shape of the through hole in the long side direction of the substrate is aligned with the shape of the narrow region of the land pattern, in a plan view; and solder members are formed in a wall shape on the mounting substrate, are formed in the through holes on the mounting substrate, and connects the rear electrode and the side electrode to the wide region and the narrow region, respectively.