Light Source Device Asymmetric Bonding Film Layout
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Solution Overview
Problem
In light source devices with semiconductor lasers, the molten metal used for bonding can creep onto the reflecting surface, reducing its reflectivity and potentially causing short-circuits due to the formation of solder balls, which are unstable and prone to damage.
Innovation Solution
A light source device design where the end portions of the bonding films are positioned separately from the lower end of the reflecting surface, with a difference in distance between these end portions, allowing the molten metal to flow onto a non-reflecting surface and form a fillet structure instead of a solder ball, preventing it from contacting the reflecting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end portions of the bonding films are disposed separately from the lower end portion of the reflecting surface, then the molten metal is prevented from being deposited on the reflecting surface, but the molten metal may be projected to a lateral side forming solder balls
Solution Approach 1:
The bonding films are designed with different lengths, creating asymmetric local qualities. The first bonding film extends closer to the reflecting surface while the second bonding film extends further laterally, allowing the molten metal to be directed onto the base member surface rather than forming solder balls.
Solution Approach 2:
The bonding films are configured asymmetrically in terms of their extension distances from the reflecting surface. This asymmetric arrangement guides the molten metal flow in a controlled manner, preventing both deposition on the reflecting surface and lateral projection forming solder balls.
2Strength
If the bonding films are extended closer to the reflecting surface, then the bonding strength is improved, but the molten metal may creep up on the reflecting surface
Solution Approach 1:
The first bonding film is designed to extend closer to the reflecting surface to maximize bonding strength, while the second bonding film is configured with a different extension distance. This local quality differentiation allows the bonding films to provide strong adhesion without allowing molten metal to creep onto the reflecting surface.
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 design maintains high reflectivity of the reflecting surface and prevents short-circuits by ensuring the molten metal does not creep onto the reflecting surface, enhancing the reliability and durability of the light source device.
Implementation Method 1
a metal bonding member fuse-bonded to the first bonding film and the second bonding film to each other
Implementation Method 2
a metal bonding member fuse-bonded to the first bonding film and the second bonding film to each other
Implementation Method 3
a reflecting surface that reflects light emitted from the semiconductor laser
Data Source
AI summary
A light source device includes: a base member; a semiconductor laser mounted on an upper surface of the base member; a lateral wall portion having: a lower surface facing the upper surface of the base member and being a non-reflecting surface, and a reflecting surface that reflects light emitted from the semiconductor laser, is connected to the lower surface of the lateral wall portion at a lower end portion of the reflecting surface, and is inclined with respect to the upper surface of the base member; a first bonding film that is a metal film disposed in a region on the upper surface of the base member facing the lower surface of the lateral wall portion; a second bonding film that is a metal film disposed on the lower surface of the lateral wall portion; and a metal bonding member fuse-bonded to the first bonding film and the second bonding film to each other. An end portion of the first bonding film at a reflecting-surface side and an end portion of the second bonding film at the reflecting-surface side are located separately from the lower end portion of the reflecting surface. A distance between the end portion of the first bonding film at the reflecting-surface side and the lower end portion of the reflecting surface is different from a distance between the end portion of the second bonding film at the reflecting-surface side and the lower end portion of the reflecting surface.