Compact Proximity Sensor with Baffle Optical Isolator
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Solution Overview
Problem
Proximity sensors with separate radiation sources and detectors suffer from internal radiation propagation issues, leading to unreliable proximity sensing due to polluting signals, which complicates their design and increases size and complexity.
Innovation Solution
A proximity sensor package with a baffle forming part of an optical isolator, positioned between the radiation source and detector, and an over-molding with lenses to prevent internal radiation propagation, allowing the source and detector to be housed together while maintaining reliable sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radiation source and detector are housed in separate packages, then internal radiation propagation is reduced, but the device size and complexity increase
Solution Approach 1:
The patent combines the radiation source and detector into a single integrated package, eliminating the need for separate packages while maintaining reliable proximity sensing through the addition of an optical isolator component
2Device complexity
If the radiation source and detector are housed in the same package, then device complexity is reduced, but internal radiation propagation causes unreliable sensing
Solution Approach 1:
The patent segments the internal package structure by introducing an optical isolator (baffle) that divides the package into source and detector regions, preventing direct optical coupling while allowing electrical integration
Solution Approach 2:
The optical isolator acts as an intermediary component between the radiation source and detector, blocking internal radiation propagation while allowing the two components to coexist in the same package
3Reliability
If a baffle is added to prevent internal radiation propagation, then sensing reliability improves, but manufacturing complexity increases
Solution Approach 1:
The attachment pad is designed to serve multiple functions: it provides electrical mounting for the source and detector, structural support for the package, and forms the optical isolator (baffle) to prevent internal radiation propagation
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 configuration enables reliable proximity sensing by minimizing internal radiation propagation, allowing for a compact, single-package design with improved control over the radiation source and reduced manufacturing complexities.
Implementation Method 1
a baffle which forms at least part of an optical isolator, the optical isolator substantially preventing the internal propagation of radiation between the source and the detector within the sensor package
Implementation Method 2
capturing light which is reflected back to the detector by an object
Implementation Method 3
a radiation detector housed within the sensor package
Data Source
AI summary
A proximity sensor includes a sensor package having an attachment pad with a radiation source and a radiation detector housed within the sensor package. The source and the detector are held in a fixed relation to the attachment pad, and are mounted by one of a direct or indirect attachment to the attachment pad. A portion of the attachment pad is adapted to form a baffle which forms at least part of an optical isolator. The optical isolator is adapted to substantially prevent the internal propagation of radiation between the source and the detector within the sensor package.