Gas Measuring Device Bar-Shaped Radiation Spot Shadowing

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Solution Overview

Problem

Existing gas concentration measuring devices face accuracy issues due to maladjustment and shadowing effects, leading to measurement drift and errors, particularly when using non-imaging concentrators and sharp focusing techniques.

Innovation Solution

A measuring device with a main optical unit comprising an optical element and parallel reflection surfaces that uniformly distribute radiation intensity on the detector, reducing shadowing effects by imaging the radiation source as a bar-shaped spot and using parallel reflection surfaces to minimize contrast and radiation loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the radiation guide means is designed to focus radiation sharply to the radiation detector to achieve high radiation intensity, then the signal-to-noise ratio is improved, but the measurement accuracy becomes very sensitive to mechanical maladjustment

Engineering Contradiction:

Improveradiation intensityVSAvoidmeasurement accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The radiation guide means is divided into a collimating unit and a main optical unit with separate functions. The collimating unit prepares the radiation beam, while the main optical unit with parallel reflection surfaces performs the final focusing, distributing radiation uniformly across the detector without creating sensitive shadow zones.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from point-to-point focusing to a distributed focusing approach where the radiation spot is extended along one dimension (bar-shaped spot) while maintaining focus in the perpendicular dimension, reducing sensitivity to maladjustment.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If non-imaging concentrators are used to bundle parallel radiation and generate uniform radiation distribution, then the radiation distribution is improved, but shadowing effects cause intensity shifts and measurement drift

Engineering Contradiction:

Improveradiation distributionVSAvoidmeasurement stability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

Instead of using non-imaging concentrators that bundle radiation, the patent uses an imaging optical system with parallel reflection surfaces that distributes radiation in a controlled manner, inverting the approach to eliminate shadowing-induced intensity shifts.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the potential harm of shadowing into a benefit by using parallel reflection surfaces that distribute shadow effects uniformly across the detector, transforming localized intensity reductions into uniform reductions that do not cause measurement drift.

Inventive Principle:

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

3Ease of operation

If the radiation spot is enlarged by defocusing to avoid maladjustment effects, then the sensitivity to mechanical maladjustment is reduced, but shadowing of the radiation causes considerable measurement errors

Engineering Contradiction:

Improveadjustment toleranceVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The optical element creates different radiation spot characteristics in different dimensions: focused in one dimension (perpendicular to preferred direction) for high intensity, and extended in another dimension (along preferred direction) for reduced shadowing sensitivity, achieving local optimization of both parameters.

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 solution ensures a uniform reduction in radiation intensity across the detector, minimizing the impact of shadowing and improving measurement accuracy by maintaining focus and reducing measurement errors.

Implementation Method 1

an optical element, so that the punctiform radiation source is imaged in a bar-shaped radiation spot extending along a preferred direction

Methodology Applied

Scientific EffectOptical imaging: Lens

Implementation Method 2

parallel reflection surfaces extending at right angles to the preferred direction, on the inner surfaces of which the radiation is totally reflected between the optical element and the radiation detector

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS7477395B2Measuring device

Publication Date: 2009.01.13 DRAGER SAFETY AG & CO KAAA

AI summary

A measuring device for determining the concentrations of gases by radiation absorption. The device includes at least one radiation source for generating radiation, a measuring cell, which is arranged downstream of the radiation source and in which the medium to be measured is located and at least one radiation detector, which is reached by the radiation after it has been sent through the measuring cell. A radiation guide device is provided by which the radiation is guided to the radiation detector. The radiation guide device includes a main optical unit, which has, on the one hand, an optical element (4), so that the punctiform radiation source is imaged in a bar-shaped radiation spot (5) extending along a preferred direction (1), and which has, on the other hand, parallel reflection surfaces (7, 7′), which extend at right angles to the preferred direction and at the inner surfaces of which the radiation is totally reflected between the optical element (4) and the radiation detector (3, 3′).