Proximity Sensor Using Disposable Photoresist Alignment
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Solution Overview
Problem
Conventional proximity sensors have high manufacturing costs due to the use of materials like gum, metal, or ceramic for caps, and the manufacturing process involves costly steps like aligning glue coatings and joining, which can lead to dust introduction and detection faults.
Innovation Solution
A proximity sensor design featuring a sensor chip and light-emitting device on a substrate, where a transparent molding material covers the light-emitting surface and a non-transparent molding material separates the transparent material from the sensor chip, reducing manufacturing costs and preventing light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional materials like gum, metal, or ceramic are used for caps and costly alignment steps are performed, then the manufacturing precision and reliability are improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive conventional materials (gum, metal, ceramic) with a disposable photoresist pattern that is applied, exposed, developed, and removed in a single manufacturing cycle. This photoresist-based approach eliminates the need for costly cap materials while maintaining the light-blocking function during assembly, thereby reducing manufacturing cost without sacrificing alignment precision.
Solution Approach 2:
The patent substitutes mechanical alignment systems (requiring manual or automated alignment of caps and glue coatings) with a photochemical alignment system. The photoresist pattern is directly patterned onto the substrate using photolithography, which provides inherent alignment precision through the exposure process itself, eliminating the need for separate mechanical alignment steps.
2Reliability
If conventional cap materials and alignment processes are used, then the structural integrity and light isolation are improved, but dust introduction and detection faults occur
Solution Approach 1:
The photoresist pattern serves as a temporary light-blocking structure that is present only during the critical assembly phase. After the alignment marks are captured and the sensor is assembled, the photoresist is completely removed, eliminating any potential source of dust contamination that would persist with conventional cap materials. The temporary nature of the photoresist ensures it fulfills its function without becoming a permanent contamination source.
Solution Approach 2:
The patent extracts and removes the photoresist material after it has served its alignment and light-blocking purpose. By completely removing the alignment structure after use, the system eliminates the potential for dust introduction that would occur if permanent cap materials remained in place, thereby improving detection accuracy by preventing contamination.
3Reliability
If multiple separate components and alignment steps are used, then the functional performance is improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The patent merges the light-blocking cap function and the alignment marking function into a single integrated photoresist pattern. This single structure simultaneously provides both the optical isolation needed for sensor functionality and the alignment references needed for assembly, thereby reducing device complexity while maintaining functional performance. The merged structure eliminates the need for separate cap components and alignment marks.
Solution Approach 2:
The photoresist pattern serves multiple functions: it acts as a light-blocking cap during assembly, provides alignment marks for capturing sensor information, and serves as a temporary structural element. This multi-functional approach reduces the number of separate components needed, thereby simplifying the device structure while maintaining all necessary functions for sensor operation and assembly.
Data Source
AI summary
A proximity sensor is provided according to the embodiments of the present disclosure, comprising: a sensor chip; a light-emitting device; a substrate, the sensor chip and the light-emitting device being located on the substrate; a transparent molding material covering a light-emitting surface of the light-emitting device; and a non-transparent molding material separating the transparent molding material from the sensor chip.