Optical Ranging Sensor Attenuation Wall for Ambient Light Noise

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Solution Overview

Problem

Optical noise from ambient light sources affects the accuracy and consistency of optical ranging sensors, particularly in environments with wide-angle transmission apertures, leading to reduced signal-to-noise ratio and increased manufacturing complexity and cost.

Innovation Solution

A housing cap with an attenuation wall is introduced between the optical radiation source and the reference sensor, creating an attenuation gap to block ambient light while allowing transmitted radiation to reach the reference sensor, eliminating the need for optical filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If optical filters are added to block ambient light, then optical noise is reduced, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveoptical noiseVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The housing cap is segmented into multiple functional regions including a transmission cavity, receiving cavity, and attenuation wall. The attenuation wall creates a first cavity that selectively transmits optical radiation while blocking ambient light, dividing the housing into distinct functional zones that reduce optical noise without requiring additional optical filters

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The housing cap structure performs multiple functions: it protects internal components, directs transmitted optical radiation to the target, receives reflected radiation, and attenuates ambient light through the attenuation wall. This multi-functional design eliminates the need for separate optical filters while maintaining noise reduction capabilities

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If optical filters are added to block ambient light, then optical noise is reduced, but manufacturing cost increases

Engineering Contradiction:

Improveoptical noiseVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The attenuation function is merged into the housing cap structure itself through the attenuation wall, combining the housing function with the optical attenuation function. This integration eliminates the need for separate optical filter components, reducing part count and manufacturing cost while maintaining the ability to block ambient light

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing cap is designed as a multi-functional component that simultaneously provides mechanical protection, optical transmission direction, and ambient light attenuation. This universal design approach eliminates the need for additional optical filters, simplifying manufacturing and reducing costs

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Area of moving object

If wide-angle transmission aperture is used, then transmission capability is improved, but optical noise from ambient light increases

Engineering Contradiction:

Improvetransmission aperture areaVSAvoidoptical noise

Core Design Contradiction:

Area of moving objectVSObject-affected harmful factors

Solution Approach 1:

The attenuation wall creates a localized cavity structure with specific geometric properties that allow wide-angle transmission of intended optical radiation while selectively blocking ambient light from different angles. The local geometric configuration provides directional selectivity, maintaining transmission capability while reducing optical noise

Inventive Principle:

Principle #3Local quality

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 the accuracy and reliability of optical ranging sensors by reducing optical noise, simplifying manufacturing, and lowering costs by eliminating the need for additional filters.

Implementation Method 1

an attenuation wall positioned between the optical radiation source and the reference sensor, defining an attenuation gap through which the portion of the ranging optical radiation passes

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentUS20250237744A1Attenuation wall to reduce optical noise in an optical ranging sensor

Publication Date: 2025.07.24 STMICROELECTRONICS INT NV

AI summary

A housing cap for an optical ranging sensor and an electronic system for transmitting and receiving optical radiation while minimizing optical noise, such as ambient light, received at the reference sensor of the optical ranging sensor are provided. An example housing cap for an optical ranging sensor may include a barrier wall defining a transmission cavity and a receiving cavity. The transmission cavity including an optical radiation source positioned to direct ranging optical radiation through a transmission opening toward a target object, a reference sensor positioned to receive a portion of the ranging optical radiation, and an attenuation wall positioned between the optical radiation source and the reference sensor, defining an attenuation gap through which the portion of the ranging optical radiation passes. The receiving cavity including an optical radiation receiver positioned to receive ranging optical radiation reflected off the target object through a receiver opening.