Optical Proximity Sensor Light Blocking Barrier Design
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Solution Overview
Problem
Existing optical proximity sensors face issues with crosstalk due to direct light transmission between emitters and detectors, leading to false positives and increased manufacturing costs, particularly with the use of separately manufactured metal shields or double mold processes.
Innovation Solution
A sensor design incorporating an infrared light blocking ink or barrier that partially covers the light emitter and detector, inhibiting direct communication and reducing crosstalk, while allowing reflected light to be detected effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a separately manufactured metal shield is used to block direct light transmission between light emitter and light detector, then crosstalk is reduced, but manufacturing cost increases due to material cost, custom machinery, and assembly complexity
Solution Approach 1:
The patent merges the light blocking function with the optically transmissive material itself by forming a light blocking barrier directly within the material structure. This eliminates the need for separate metal shields and their associated manufacturing and assembly processes, thereby reducing manufacturing cost while maintaining crosstalk reduction effectiveness.
Solution Approach 2:
The patent extracts the light blocking function from a separate component (metal shield) and integrates it directly into the optically transmissive material through a molded barrier structure. This integration eliminates the need for custom machinery to form and place separate shields, simplifying manufacturing while achieving the same optical isolation purpose.
2Object-affected harmful factors
If a separately manufactured metal shield is used to block direct light transmission, then crosstalk is reduced, but device reliability decreases due to potential denting, deformation, or displacement during use
Solution Approach 1:
By merging the light blocking barrier with the optically transmissive material structure, the patent eliminates the risk of the barrier becoming detached or misaligned. The integrated barrier moves with the material as a unified structure, ensuring consistent optical performance and maintaining reliability throughout the device's operational life.
Solution Approach 2:
The patent creates a localized light blocking barrier within specific regions of the optically transmissive material where light transmission needs to be controlled. This localized approach allows the material to maintain its overall transmissive properties while providing targeted blocking where needed, ensuring both functionality and structural integrity.
3Object-affected harmful factors
If a double mold process is used to form light blocking compound over light transmissive compound, then crosstalk is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the light blocking and light transmissive functions into a single molded component with integrated barriers. This single-mold approach eliminates the need for sequential molding operations and the complexity of coordinating two separate manufacturing processes, while achieving the same optical separation effect.
Solution Approach 2:
The patent uses a composite structure within the optically transmissive material, incorporating light blocking barrier regions directly into the material matrix. This composite approach allows both light blocking and light transmission functions to coexist in a single material component, eliminating the need for layered molding processes.
4Ease of manufacture
If a light blocking barrier is integrated into the optically transmissive material with a gap having parallel walls perpendicular to the top surface, then crosstalk is reduced and manufacturing is simplified, but the barrier structure requires precise geometric control
Solution Approach 1:
The patent specifies particular geometric parameters for the light blocking barrier (parallel walls substantially perpendicular to the top surface, gap configuration) that optimize both manufacturing ease and optical performance. These parameter specifications provide clear manufacturing guidelines that balance precision requirements with manufacturability, ensuring consistent results without excessive 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
This solution effectively reduces crosstalk and manufacturing costs by using a layer of infrared light blocking ink or barrier, enhancing the performance and reliability of proximity, color, and motion sensors without the need for expensive shielding or complex molding processes.
Implementation Method 1
a light blocking compound 112 that blocks transmission of substantially all light within a particular spectrum through a light blocking compound 112
Implementation Method 2
light transmissive compounds 114 that allow the transmission of substantially all light within a particular spectrum
Implementation Method 3
light emitters 102 can be light emitting diodes (LEDs) that emit infrared light
Implementation Method 4
light detectors 104 can be photodiodes configured to detect infrared light
Data Source
AI summary
A sensor comprising a light emitter and light detector coupled directly with or formed directly on a lead frame and directly covered and encapsulated by a layer of light transmissive compound. A gap in the light transmissive compound between the light emitter and the light detector wherein in some embodiments the gap can be filled with a light blocking barrier material.