Conductive-Wire Optical Member for Laser Damage Detection
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Solution Overview
Problem
Existing 3D sensing systems face issues with optical members in laser modules that can cause harm due to direct laser emission if damaged, and are not effectively detected for damage in harsh environments, leading to potential accidents and injuries. Additionally, these systems suffer from cracking during high-temperature reflow processes.
Innovation Solution
An optical member with a wire containing an electrically conductive substance, such as silver, is integrated into the laser module, allowing for damage detection through conductivity monitoring and using a curable epoxy resin composition for heat resistance, along with a printing process for efficient wire formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an optical member including a diffuser or diffractive optical element is used to diffuse laser light and reduce harm to eyes, then safety is improved, but the optical member is prone to damage such as cracking or peeling due to impact or drops, which can lead to direct laser light emission to eyes
Solution Approach 1:
A wire containing an electrically conductive substance is embedded in the optical member before it is subjected to impact or drops. This preliminary placement of the conductive wire enables subsequent detection of damage through monitoring changes in electrical conductivity, allowing for early identification of cracking or peeling before they lead to complete optical member failure and direct laser light emission.
Solution Approach 2:
The electrical conductivity of the embedded wire is continuously monitored to provide feedback on the structural integrity of the optical member. When cracking or peeling occurs, the conductivity changes, providing immediate feedback that the optical member is damaged and may no longer effectively diffuse laser light, alerting the system to stop operation or take corrective action.
2Reliability
If the optical member is degraded or damaged in a harsh environment such as sunlight, vibration, or the like used outdoors for automatic driving, then safety is compromised due to erroneous actuation, but there is no means for detecting damage quickly
Solution Approach 1:
The mechanical or visual inspection methods for detecting optical member damage are replaced with an electrical detection system. The embedded conductive wire transforms the damage detection problem from a mechanical/visual inspection task into an electrical measurement task, where changes in electrical conductivity clearly indicate structural damage such as cracking or peeling, enabling reliable detection in harsh outdoor environments.
Solution Approach 2:
The electrically conductive wire serves as an intermediary element between the optical member's structural integrity and the detection system. Instead of directly monitoring the optical properties or physical structure of the optical member, the conductive wire mediates the detection process by translating structural damage into measurable electrical conductivity changes.
3Strength
If high melting point lead-free solder is used as bonding material in reflow process, then bonding strength is improved, but heating treatment temperature increases to 240-260°C, causing cracking in optical members
Solution Approach 1:
The problematic thermal stress affecting the optical member during the reflow process is extracted and isolated by embedding an electrically conductive wire that is specifically positioned and configured to monitor for cracking. This allows the use of high-temperature lead-free solder for strong bonding while simultaneously providing a detection mechanism to identify any cracking that occurs in the optical member during or after the reflow process.
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 optical member can detect damage, prevent direct laser emission, reduce injury risks, and withstand high-temperature reflow processes, thereby enhancing safety and reliability in 3D sensing applications.
Implementation Method 1
a wire containing an electrically conductive substance... allowing for detection of damage through monitoring its conducting state
Implementation Method 2
manufactured using a printing process like inkjet or screen printing
Data Source
AI summary
The present disclosure provides an optical member for use in a laser module that includes a surface emitting laser, the optical member being capable of detecting damage (cracking, peeling, and the like), a method for manufacturing the optical member, a laser module including the optical member, and a laser device.