Laser Diode Glass Cap Bonding for Flat Optical Windows
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Solution Overview
Problem
The existing light source devices with glass caps suffer from deteriorated flatness of the light-transmitting portion, which affects the transmission of laser light and overall performance.
Innovation Solution
A light source device is designed with a cap structure that includes a first glass portion and a second glass portion, bonded via an electrically conductive layer, allowing for improved flatness and smoothness of the light-transmitting surface, and a method for manufacturing this cap structure that involves anodic bonding and antireflection coating formation to enhance light transmission and reduce stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass cap covers a laser diode on a substrate, then the laser diode is protected and enclosed, but the flatness of the light-transmitting portion of the glass cap deteriorates
Solution Approach 1:
The glass cap is divided into multiple glass portions (first glass portion, second glass portion, third glass portion) that are separately formed and then bonded together. This segmentation allows each portion to be manufactured with high flatness independently, avoiding the flatness deterioration that occurs when forming a single large glass cap that fully encloses the laser diode.
Solution Approach 2:
Multiple glass portions with high flatness are bonded together using an electrically conductive layer to form the complete glass cap. This merging process combines the advantages of individual small portions (high flatness) to create the full protective enclosure, resolving the contradiction between protection and flatness.
2Manufacturing precision
If multiple glass portions are bonded together to improve flatness, then light transmission is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
An electrically conductive layer is introduced as an intermediary between the glass portions to facilitate bonding. This intermediary layer simplifies the bonding process by providing a reliable bonding interface, making the multi-portion construction more manageable despite the increased structural complexity.
Solution Approach 2:
The bonding process utilizes parameter changes (temperature, electrical conductivity) to join the glass portions. By controlling these parameters, the complex task of bonding multiple glass portions is simplified into a controlled manufacturing process that achieves high flatness while managing structural complexity.
3Device complexity
If a single glass cap is used to enclose the laser diode, then the structure is simple, but mass production efficiency is reduced
Solution Approach 1:
The glass cap is segmented into multiple portions that can be manufactured separately and then assembled. This segmentation enables parallel manufacturing of multiple caps simultaneously, significantly improving mass production efficiency while maintaining a relatively simple overall structure through the use of standardized bonding processes.
Solution Approach 2:
The glass portions are prepared and pre-formed before the final assembly step. This preliminary action allows for efficient manufacturing of individual components that can be quickly bonded together, enhancing mass production capability without requiring complex real-time manufacturing processes.
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 achieves improved flatness and smoothness of the light-transmitting portion, enhancing the transmission of laser light and reducing stray light, while enabling efficient mass production and cost-effective manufacturing of the light source device.
Implementation Method 1
a first glass portion and a second glass portion, which are different from each other, are anodically bonded to a plate
Implementation Method 2
antireflection coating formation to enhance light transmission and reduce stray light
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A light source device includes: a laser diode; a substrate directly or indirectly supporting the laser diode; and a cap secured to the substrate and covering the laser diode. The cap includes a first glass portion configured to transmit laser light that is emitted from the laser diode, and a second glass portion. At least one of the first glass portion and the second glass portion includes an alkaline glass region. The first glass portion and the second glass portion are bonded together via an electrically conductive layer that is in contact with the alkaline glass region.