Optical Sensor Temperature Control for Narrow-Band Filter Alignment

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Solution Overview

Problem

Active optical sensor systems face reduced accuracy and reliability due to increased noise from ambient light and temperature fluctuations, which cause shifts in the emission wavelength of the light source and transmission spectrum of the filter element, leading to a reduced signal-to-noise ratio.

Innovation Solution

A temperature control system regulates the source temperature of the light source based on the filter element's temperature to maintain the emission wavelength within the filter's transmission band, using a temperature control device with sensors and a control unit to adjust the source temperature to compensate for temperature-dependent shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If filter elements with a very wide transmission range are used to ensure sufficient light transmission under temperature fluctuations, then the transmission intensity is maintained, but the influence of noise from ambient light increases and the signal-to-noise ratio decreases

Engineering Contradiction:
Improvetransmission intensityVSAvoidnoise influence
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the emission wavelength of the light source based on the measured temperature of the filter element. Instead of using a wide transmission range filter, the system compensates for temperature-induced wavelength shifts by changing the light source parameters (wavelength) to match the filter's transmission characteristics at the current temperature, thereby maintaining high transmission intensity while using a narrow-band filter to reject ambient light noise

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by measuring the filter element's temperature with a temperature sensor and using this information to adjust the light source's emission wavelength. The control unit continuously monitors the temperature and modifies the light source parameters accordingly, creating a closed-loop system that maintains optimal alignment between the emission wavelength and the filter's transmission band despite temperature variations

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the transmission range of the filter element is widened to accommodate temperature shifts, then the emission wavelength remains within the transmission band, but the signal-to-noise ratio is reduced due to increased ambient light noise

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidtemperature tolerance
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system changes the emission wavelength parameter of the light source dynamically based on temperature measurements. By adjusting this parameter, the system maintains precise alignment with the narrow filter transmission band across different temperatures, achieving both high signal-to-noise ratio and temperature adaptability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The feedback mechanism uses temperature sensor data to continuously adjust the light source wavelength, ensuring the emission remains centered in the narrow filter transmission band. This closed-loop control enables the system to maintain high measurement precision while adapting to temperature variations without requiring a wide transmission range filter

Inventive Principle:
Principle #23Feedback

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 approach enhances the signal-to-noise ratio by filtering out irrelevant wavelengths, resulting in more accurate and reliable measurements, and extends the lifespan of the light source through efficient temperature management.

Implementation Method 1

an optical filter element arranged in a receiving beam path for the reflected components of the light

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

a temperature control device configured to regulate the source temperature of the light source as a function of the filter element's temperature

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4022352B1Active optical sensor system with temperature control
Publication Date: 2026.03.25 VALEO SCHALTER & SENSOREN GMBH
  • EP4022352B1 patent drawingFigure 1
  • EP4022352B1 patent drawingFigure 2~3

AI summary

An active optical sensor system (1) with temperature regulation comprises a light source (2), configured to emit light (3) in the direction of an object (4), at least one optical detector (5), configured to detect portions (6) of the light (3) reflected from the object (4), and an optical filter element (7) arranged in a reception beam path for the reflected portions (6). The sensor system (1) comprises a temperature regulating device (8), configured to regulate a source temperature of the light source (2) depending on a filter temperature of the filter element (7).