Laser-Welded Sensor Case Structure to Prevent Resin Burrs
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Solution Overview
Problem
Existing sensor module designs using laser welding result in resin burrs protruding outward, affecting appearance and requiring additional processing, which decreases productivity.
Innovation Solution
Incorporating a reflective intermediate layer along the outer peripheral edge of the joining surfaces in the sensor module, which reflects laser light to prevent melting and protrusion of resin at the joint, using materials with absorptive or transmissive properties for the cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding is used to join the front case and rear case, then sealing performance is improved, but resin burrs protrude toward the outside causing poor appearance
Solution Approach 1:
A metal layer is introduced as an intermediary substance between the two resin cases. This metal layer serves as a mediator that absorbs laser light energy and generates heat to melt the resin cases for welding, while its high reflectivity prevents laser light from directly melting the resin at the joining surface, thereby preventing resin burr formation and improving appearance quality.
Solution Approach 2:
The invention changes the optical parameters of the joining surface by coating it with a metal layer having high reflectivity. This parameter change allows the surface to reflect laser light instead of absorbing it, preventing direct melting of the resin and eliminating resin burrs while maintaining effective welding through the metal layer's thermal conduction.
2Reliability
If laser welding is used to join the front case and rear case, then sealing performance is improved, but additional work is required to remove protruding portions
Solution Approach 1:
The metal layer acts as an intermediary that enables welding while preventing resin burr formation. By using this intermediary, the welding process directly produces a clean joining surface without requiring subsequent removal operations, thereby improving manufacturing efficiency while maintaining sealing performance.
Solution Approach 2:
The invention converts the potentially harmful effect of laser light directly melting resin (which causes burrs) into a beneficial process. The metal layer reflects laser light to prevent direct resin melting, while still allowing sufficient heat transfer to enable welding, thus turning a harmful side effect into a controlled and beneficial welding process.
3Shape
If a reflective intermediate layer is added to prevent resin burrs, then appearance quality is improved, but device complexity increases
Solution Approach 1:
The metal layer is applied only to the specific joining surface area where laser welding occurs, rather than throughout the entire case structure. This localized application improves appearance quality at the critical joining area while minimizing the overall structural complexity and material usage.
Solution Approach 2:
The invention creates a composite structure by combining the metal layer with the resin cases. This composite material approach allows the joining surface to have both the aesthetic qualities of a clean, burr-free surface and the functional properties of effective laser welding, without significantly increasing overall device complexity.
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
Prevents resin protrusion, maintaining a clean appearance and eliminating the need for additional processing, while ensuring stable welding and design flexibility.
Implementation Method 1
The intermediate layer is reflective of light, and is formed along an outer peripheral edge of a region, in the opening end, in which the opening end faces the joining surface. Laser light, from among irradiated light, that is incident on the intermediate layer formed along the outer peripheral edge of the region in which the opening end faces the joining surface, is reflected off the intermediate layer.
Implementation Method 2
the first case may be made of a synthetic resin material that has absorptive properties with respect to the laser light
Implementation Method 3
the second case may be made of a synthetic resin material that has transmissive properties with respect to the laser light
Implementation Method 4
the front case and the rear case are joined to each other using welding by irradiation of laser light
Data Source
Figure 1(A)~1(B)
Figure 2~3
Figure 4~5
AI summary
A sensor module according to an embodiment of the present technology includes a sensor element, a first case, a second case, and an intermediate layer. The first case includes an opening end and accommodates therein the sensor element. The second case includes a joining surface welded to the opening end. The intermediate layer is reflective of light, and is formed along an outer peripheral edge of a region, in the opening end, in which the opening end faces the joining surface.