Lidar Radiation Source Temperature Control for Signal Noise Ratio

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Solution Overview

Problem

LIDAR devices face challenges in maintaining a high signal-to-noise ratio due to the need for broader wavelength bandpass filters to accommodate beams at angles greater than 0°, which negatively affects signal quality.

Innovation Solution

The use of multiple radiation sources with settable operating temperatures and emission wavelengths, allowing for angle-dependent emission wavelengths that adapt to the bandpass filter's shift, enabling a narrower filter bandwidth and improved signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a broader transmitted wavelength range is used in the bandpass filter to accommodate beams at angles greater than 0°, then the signal transmission is improved, but the signal-to-noise ratio deteriorates due to increased interfering reflections

Engineering Contradiction:

Improveangular acceptance rangeVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention changes the wavelength parameter of the radiation source as a function of the emission angle. By adjusting the wavelength to match the angle-dependent shift of the bandpass filter's transmission range, the system maintains optimal signal transmission across different angles while keeping the filter bandwidth narrow, thus preserving the signal-to-noise ratio

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic adjustment of the radiation source wavelength based on the emission angle. The wavelength is actively modified to track the filter's transmission range shift, enabling the system to adapt to angular variations without requiring a broader filter bandwidth

Inventive Principle:

Principle #15Dynamics

2Reliability

If a narrower transmitted wavelength range is used in the bandpass filter to improve the signal-to-noise ratio, then interfering reflections are blocked, but beams at angles greater than 0° cannot be transmitted

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidangular acceptance range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention applies preliminary adjustment of the radiation source wavelength before the beam enters the scanning range. By pre-compensating for the angle-dependent filter shift, the system ensures that beams at various angles will be transmitted through the narrow bandwidth filter without requiring real-time filter adjustment

Inventive Principle:

Principle #10Preliminary action

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 allows for a significant reduction in filter bandwidth, enhancing the signal-to-noise ratio while maintaining a cost-effective and technically simple design, effectively blocking interfering reflections and reducing the likelihood of detecting 'ghost objects'.

Implementation Method 1

at least one radiation source has a settable operating temperature and/or a settable emission wavelength as a function of an emission angle of the electromagnetic beams generated by the at least one radiation source

Methodology Applied

Scientific EffectTemperature-dependent wavelength emission:

Implementation Method 2

The wavelength of the generated laser radiation or electromagnetic beams is dependent on the temperature of the semiconductor laser

Methodology Applied

Scientific EffectSemiconductor laser wavelength temperature dependence:

Implementation Method 3

optical bandpass filters, for example, interference filters, can be situated in the receiving path of the LIDAR device to block interfering reflections

Methodology Applied

Scientific EffectOptical bandpass filtering: Filter (optical)

Implementation Method 4

in the case of the detection of beams having an angle of incidence greater than 0° in relation to an optical axis of the LIDAR device, a shift of the transmitted wavelength range of the bandpass filter toward shorter wavelengths occurs

Methodology Applied

Scientific EffectAngle-dependent wavelength shift:

Data Source

PatentUS11561285B2Transmitting unit and lidar device using at least two radiation sources having at least one of a settable operating temperature and a settable emission wavelength to generate and emit punctiform or linear electromagnetic beams for scanning a scanning range

Publication Date: 2023.01.24 ROBERT BOSCH GMBH

AI summary

A transmitting unit of a LIDAR device includes at least two radiation sources for generating and emitting punctiform or linear electromagnetic beams into a scanning range, at least one of the radiation sources including an operating temperature settable as a function of an emission angle of the electromagnetic beams generated by the at least one radiation source. The different operating temperatures can generate beams having angle-dependent emission wavelengths, which can result in an improvement of the signal-to-noise ratio of a LIDAR device.