Optical Proximity Sensor IR Blocking Layer for Crosstalk Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical proximity sensors rely on metal shields to minimize crosstalk and interference, which are difficult to manufacture in high volumes, expensive, and prone to detachment, leading to reliability issues.
Innovation Solution
An optical proximity sensor design that eliminates the need for a metal shield by using molded optically transmissive components with a gap between them, covered by infrared attenuating or blocking material to minimize crosstalk and interference, formed using transfer molding compounds and applied with infrared opaque layers to block unwanted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If metal shields are used to minimize crosstalk and interference, then optical isolation between emitter and detector is improved, but manufacturing difficulty increases, cost increases, and reliability decreases due to detachment issues
Solution Approach 1:
The patent extracts the light-blocking function from the metal shield structure and relocates it to the molded optical components themselves. The molded components incorporate infrared attenuating material directly into their structure, eliminating the need for separate metal shields and their associated manufacturing and assembly complexities.
Solution Approach 2:
The patent merges the light-blocking function with the structural components by incorporating infrared attenuating material into the molded optical components. This integration eliminates the need for separate metal shields and simplifies the overall device structure while maintaining optical isolation.
2Object-affected harmful factors
If metal shields are used to minimize crosstalk and interference, then optical isolation between emitter and detector is improved, but cost increases
Solution Approach 1:
The patent replaces expensive metal shields with cost-effective molded optical components that incorporate infrared attenuating material. The molded components are manufactured using standard plastic molding processes, significantly reducing material and manufacturing costs while maintaining the necessary optical isolation performance.
Solution Approach 2:
The patent uses composite materials by incorporating infrared attenuating material into the molded optical components. This allows the components to maintain structural integrity while providing the necessary infrared light blocking properties, eliminating the need for expensive metal shields.
3Object-affected harmful factors
If metal shields are used to minimize crosstalk and interference, then optical isolation between emitter and detector is improved, but reliability decreases due to detachment
Solution Approach 1:
The patent merges the light-blocking function with the structural components by incorporating infrared attenuating material into the molded optical components. This integration eliminates the need for separate metal shields that can detach, thereby improving reliability while maintaining optical isolation.
Solution Approach 2:
The patent extracts the light-blocking function from the metal shield structure and relocates it to the molded optical components themselves. This eliminates the interface between separate components that could lead to detachment, ensuring long-term reliability.
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 design enhances manufacturability, reduces costs, and improves reliability by effectively blocking undesired infrared light, maintaining high crosstalk rejection while eliminating the need for metal shields.
Implementation Method 1
the infrared attenuating or blocking material is configured to attenuate or block substantially the transmission of undesired direct, scattered or reflected infrared light between the light emitter and the light detector and thereby minimize optical crosstalk and interference between the light emitter and the light detector
Data Source
AI summary
An optical proximity sensor is provided that comprises an infrared light emitter an infrared light detector, a first molded optically transmissive infrared light pass component disposed over and covering the light emitter and a second molded optically transmissive infrared light pass component disposed over and covering the light detector. Located in-between the light emitter and the first molded optically transmissive infrared light pass component, and the light detector and the second molded optically transmissive infrared light pass component is a gap. Layers of infrared opaque, attenuating or blocking material are disposed on at least some of the external surfaces forming the gap to substantially attenuate or block the transmission of undesired direct, scattered or reflected light between the light emitter and the light detector, and thereby minimize optical crosstalk and interference between the light emitter and the light detector.