Optical Assembly Cover Angled Surfaces Reduce Cross-Talk

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Solution Overview

Problem

Optical assemblies, such as proximity sensors, face cross-talk issues due to light being reflected from components other than the object, reducing sensitivity and signal quality.

Innovation Solution

Incorporating a cover with a cavity structure that refracts light towards a predetermined direction, specifically with angled surfaces between 40° to 65°, to reduce cross-talk by directing reflected light away from the photodetector and maintaining signal intensity and signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional optical assembly structure is used, then the device is simple, but cross-talk occurs reducing sensitivity

Engineering Contradiction:

ImprovesensitivityVSAvoidoptical assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The optical assembly is segmented into distinct functional zones using a partition structure that divides the internal space. This segmentation separates the light emitting region from the light detecting region, preventing cross-talk while maintaining structural organization and sensitivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cover structure with specific geometric features acts as an intermediary element between the light emitting device and the external environment. The cover includes a light-emitting surface facing the light emitting device and a light-receiving surface facing away from it, mediating light transmission while blocking stray light paths that would cause cross-talk.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the cover surface is flat, then manufacturing is simple, but reflected light causes cross-talk

Engineering Contradiction:

Improvecross-talkVSAvoidcover structure

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The cover structure employs asymmetric geometry where the light-emitting surface and light-receiving surface are positioned at different orientations and locations. The light-receiving surface is angled or positioned to face away from the photodetector, creating an asymmetric light path that directs reflected light away from the detection region, thereby reducing cross-talk.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The solution moves from a two-dimensional flat surface concept to a three-dimensional structured cover with multiple surfaces at different angles and positions. By introducing vertical and angular dimensions, the cover creates controlled light paths that separate reflected light from the photodetector while maintaining manufacturability through standard molding techniques.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If light is allowed to reflect freely, then signal intensity is high, but cross-talk increases

Engineering Contradiction:

Improvecross-talkVSAvoidsignal intensity

Core Design Contradiction:

Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

Different regions of the optical assembly are assigned different optical properties. The cover's light-emitting surface is designed to transmit light effectively toward the object, while the light-receiving surface is configured to reflect or redirect light away from the photodetector. This local differentiation of optical functions allows signal transmission while blocking cross-talk paths.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cover structure converts potentially harmful reflected light into a beneficial directional control mechanism. By strategically positioning and angling the light-receiving surface, reflected light that would otherwise cause cross-talk is redirected away from the photodetector, transforming a harmful effect into a means of cross-talk suppression while preserving signal intensity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 cross-talk, enhances signal intensity, and improves signal-to-noise ratio, providing stable performance and increased optical assembly stability.

Implementation Method 1

the one or more surfaces constituting the cavity can refract the light impinging thereon toward a predetermined direction

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

avoid the light reflected from a distal surface of the cover from entering the light detecting device

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11892570B2Optical assembly that generates distinctive irradiance pattern of light

Publication Date: 2024.02.06 ADVANCED SEMICON ENG INC

AI summary

An optical assembly includes a light-emitting device, a partition structure and a cover. The partition structure defines a first space for accommodating the light-emitting device. The cover is disposed over the partition structure. The cover has a first surface facing the partition structure and a second surface opposite to the first surface. A light emitted by the light-emitting device forms a first irradiance pattern projected on the second surface of the cover, and the first irradiance pattern includes a first dark zone traversing the first irradiance pattern.