Infrared Proximity Sensor Package with LCP Partitioning Divider

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Optical proximity sensors face significant challenges with infrared signal crosstalk due to stray light reflections, which limit sensing distance and device performance, especially in compact designs where infrared radiation easily passes through various materials, necessitating a solution that reduces crosstalk while being inexpensive and easy to manufacture.

Innovation Solution

An infrared proximity sensor package featuring a shield with infrared-absorbing material and a partitioning divider made of liquid crystal polymer (LCP) to attenuate and absorb undesired infrared light, positioned between the transmitter and receiver to minimize internal reflections and false signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the infrared transmitter and receiver are placed in very close proximity to achieve compact packaging, then the device size is reduced, but optical crosstalk increases due to stray light reflections

Engineering Contradiction:

Improvepackage sizeVSAvoidoptical crosstalk

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The housing is divided into separate recesses for the transmitter and receiver using partitioning walls made of LCP material. This segmentation physically separates the optical paths of the transmitter and receiver, preventing stray light from the transmitter from reaching the receiver while maintaining compact packaging.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

LCP material is introduced as an intermediary substance in the form of partitioning walls and housing structure. This material acts as an optical barrier that absorbs and attenuates infrared stray light, mediating between the transmitter and receiver to prevent crosstalk while allowing the components to remain in close proximity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional materials are used in the housing, then manufacturing is simple and inexpensive, but infrared radiation passes through them unattenuated causing crosstalk

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidinfrared transmission

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The optical properties of the housing material are changed by selecting LCP material with specific infrared absorption characteristics. This parameter change enables the material to attenuate infrared radiation effectively while maintaining ease of manufacturing through conventional molding processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

LCP material is used as a composite solution that combines the desired optical properties (infrared absorption) with manufacturability. The material integrates the light-absorbing characteristics needed to block crosstalk while remaining compatible with standard manufacturing processes.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If no internal shielding is provided, then manufacturing is simpler, but internally-reflected infrared light causes false detection signals

Engineering Contradiction:

Improvemanufacturing complexityVSAvoiddetection accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The housing is segmented into separate recesses for the transmitter and receiver using partitioning walls made of LCP material. This segmentation physically separates the optical paths of the transmitter and receiver, preventing stray light from the transmitter from reaching the receiver while maintaining compact packaging.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively reduces optical crosstalk by up to 98.6% by using LCP to absorb and attenuate internal reflections, enhancing the sensing distance and performance of proximity sensors while maintaining a compact design.

Implementation Method 1

the partitioning divider comprises liquid crystal polymer (LCP) such that the partitioning divider and the infrared-absorbing material of the shield cooperate together to substantially attenuate and absorb undesired infrared light

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the shield comprising an infrared-absorbing material disposed on at least a top surface thereof

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9733357B2Infrared proximity sensor package with improved crosstalk isolation

Publication Date: 2017.08.15 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

Disclosed are various embodiments of an infrared proximity sensor package comprising an infrared transmitter die, an infrared receiver die, a housing comprising sidewalls, a first recess, a second recess, a partitioning divider disposed between the first and second recesses, and an overlying shield comprising an infrared-absorbing material. The transmitter die is positioned in the first recess, and the receiver die is positioned within the second recess. The partitioning divider comprises liquid crystal polymer (LCP) such that the partitioning divider and the infrared-absorbing material of the shield cooperate together to substantially attenuate and absorb undesired infrared light that might otherwise become internally-reflected within the housing or incident upon the receiver as a false proximity or object detection signal.