Optical Sensor Cover Deflection Region for Flat-Angle Light Interference

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Solution Overview

Problem

Optical sensors, including biosensors, face interference issues due to light from the light source being reflected off the cover and reaching the light detector at flat angles, leading to reduced measurement accuracy, especially in flat structural forms used in mobile systems.

Innovation Solution

A sensor design featuring a housing with a web between the light source and detector, and a cover with a deflection region that deflects light with angles of incidence of 80 degrees or greater away from the detector, utilizing reflective coatings or prismatic structures to absorb or reflect light and prevent it from reaching the detector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the sensor is designed with a flat structural form for mobile systems, then the sensor can be integrated into mobile devices such as watches and smartphones, but light from the light source exits at a flat angle, is reflected by the cover, and reaches the light detector as interference signal, worsening measurement accuracy

Engineering Contradiction:

Improveintegration into mobile systemsVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The cover is segmented into different functional regions: a first region (deflection region) with optical elements for deflecting flat-angle light, and a second region without such elements. This segmentation allows different parts of the cover to perform different functions - one region handles interference light deflection while the other maintains normal light transmission for measurement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Optical elements (reflective coating or prismatic structure) are applied locally only to the first region of the cover where flat-angle light interference occurs, rather than covering the entire cover. This localized application deflects interference light while preserving light transmission in the second region for accurate measurements.

Inventive Principle:

Principle #3Local quality

2Reliability

If a cover is arranged over the sensor, then the sensor is protected, but part of the light from the light source reflects from the cover and reaches the light detector without being incident on the sample, creating interference signals that worsen measurement results

Engineering Contradiction:

Improvesensor protectionVSAvoidmeasurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The cover is designed with spatially varying optical properties: the first region contains optical elements (reflective coating or prismatic structure) that deflect flat-angle light away from the detector, while the second region remains optically neutral for proper light transmission. This local differentiation allows the cover to simultaneously provide protection and eliminate interference.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The reflective coating or prismatic structure in the first region converts harmful flat-angle reflected light into a beneficial deflection, redirecting it away from the light detector. The cover's reflective property, which initially causes interference, is strategically used to deflect interference light while allowing proper light transmission in the measurement region.

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

This design effectively reduces interference by deflecting at least 80% of light incident at flat angles, improving measurement accuracy by ensuring that only relevant light signals reach the detector, enhancing the performance of optical and biosensors in mobile systems.

Implementation Method 1

A web, which includes a material which absorbs or reflects light of at least one wavelength of the light source

Methodology Applied

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

Implementation Method 2

A web, which includes a material which absorbs or reflects light of at least one wavelength of the light source

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

The deflection region is formed in such a way that at least 80% of the light which is incident in the deflection region on the plane of incidence of the first cover from a predetermined direction and would be incident on the light detector is deflected away from the light detector because of an optical element

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11607158B2Sensor and biosensor

Publication Date: 2023.03.21 AMS OSRAM INT GMBH

AI summary

A sensor may include a light source, a light detector, and a housing. The housing may have a first upper side and extend from the first upper side, a first cavity and a second cavity. The light detector is arranged in the first cavity. The light source is arranged in the second cavity. A strut may be arranged between the first cavity and the second cavity and is made from a material that absorbs or reflects light. A first cover may be mounted above the first cavity and comprises a deflection region and a plane of incidence. The deflection region is designed such that 80% of the light which is incident in the deflection region on the plane of incidence of the first cover from a predetermined direction and which is incident on the light detector, is directed away from the light detector based on an optical element.