Uncertainty evaluation in non-contact aperture area measurements

Razet, Annick; Bastié, Jean

doi:10.1088/0026-1394/43/5/004

Cited by 9 publications

(12 citation statements)

References 6 publications

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“…The deviations from an ideal circle have the same order of magnitude as the edge roughness of high quality apertures, which is in the scale of few micrometers [23,24]. As described by Eq.…”

Section: Discussionmentioning

confidence: 99%

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Optical aperture area determination for accurate illuminance and luminous efficacy measurements of LED lamps

Dönsberg

Mäntynen

Ikonen

2016

Opt Rev

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The measurement uncertainty of illuminance and, consequently, luminous flux and luminous efficacy of LED lamps can be reduced with a recently introduced method based on the predictable quantum efficient detector (PQED). One of the most critical factors affecting the measurement uncertainty with the PQED method is the determination of the aperture area. This paper describes an upgrade to an optical method for direct determination of aperture area where superposition of equally spaced Gaussian laser beams is used to form a uniform irradiance distribution. In practice, this is accomplished by scanning the aperture in front of an intensity-stabilized laser beam. In the upgraded method, the aperture is attached to the PQED and the whole package is transversely scanned relative to the laser beam. This has the benefit of having identical geometry in the laser scanning of the aperture area and in the actual photometric measurement. Further, the aperture and detector assembly does not have to be dismantled for the aperture calibration. However, due to small acceptance angle of the PQED, differences between the diffraction effects of an overfilling plane wave and of a combination of Gaussian laser beams at the circular aperture need to be taken into account. A numerical calculation method for studying these effects is discussed in this paper. The calculation utilizes the Rayleigh-Sommerfeld diffraction integral, which is applied to the geometry of the PQED and the aperture. Calculation results for various aperture diameters and two different aperture-to-detector distances are presented.

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“…The deviations from an ideal circle have the same order of magnitude as the edge roughness of high quality apertures, which is in the scale of few micrometers [23,24]. As described by Eq.…”

Section: Discussionmentioning

confidence: 99%

“…Several methods for determining the area of an aperture have been developed, which utilize either mechanical contact [16,17] or optical techniques [18][19][20][21][22][23][24][25]. In addition, a spatially uniform irradiance source can be used to compare the area of two apertures [16,26,27].…”

Section: Introductionmentioning

confidence: 99%

Optical aperture area determination for accurate illuminance and luminous efficacy measurements of LED lamps

Dönsberg

Mäntynen

Ikonen

2016

Opt Rev

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“…La méthode de référence consiste à étalonner séparément la sensibilité en flux du radiomètre (exprimée en A/W) et la surface du diaphragme A (en m 2 ), puis à en faire le produit pour déterminer la sensibilité en éclairement S E,r selon la relation (2).…”

Section: L'application Aux Mesures De Sensibilité En éClairementunclassified

Étalonnage de la sensibilité en éclairement de radiomètres par la méthode de balayage de faisceau

Rougié¹,

Tayeb-Chandoul²

2013

R. franç. métrol.

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Dans la méthode « par balayage de faisceau » un faisceau monochromatique, de grande dimension et de répartition de flux uniforme, est synthétisé par la juxtaposition en de nombreuses positions d'un même faisceau. Un tel éclairement est impossible à obtenir avec un faisceau unique. L'article présente un dispositif d'étalonnage de la sensibilité en éclairement d'un radiomètre par balayage de faisceau. Sa particularité réside dans l'utilisation d'un faisceau monochromatique non cohérent, de profil non gaussien. Cette méthode a été optimisée par un calcul numérique simulant cette opération puis validée à 1,7 × 10 −3 près par comparaison à une méthode classique. Le dispositif a été mis en oeuvre pour la mesure de la sensibilité en éclairement d'une thermopile. Malgré des variations de sa sensibilité spatiale de plus de 10 %, la sensibilité moyenne a été mesurée avec une incertitude meilleure que 0,35 %. La valeur est parfaitement cohérente avec les résultats obtenus depuis une vingtaine d'années par une méthode plus classique mais a permis la division par 2 des incertitudes. Ce type de mesure, capable de prendre en compte de telles variations de sensibilité locale en éclairement, pourra être étendu à d'autres instruments.

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“…Em outros sistemas, como apresentado em [6], os resultados finais da medição são obtidos como um raio médio para a abertura e posteriormente a área é calculada.…”

Section: Conclusõesunclassified

Determinação da Incerteza de Medição na Calibração da Área de Aberturas Circulares

Costa

Barros

2010

P&P

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O Laboratório de Metrologia Dimensional do Inmetro está implementando um sistema para a medição de áreas de aberturas circulares utilizadas em medidas radiométricas e fotométricas. As medições são realizadas através da determinação das coordenadas dos pontos ao longo da borda da abertura. Dessa forma, é possível determinar o diâmetro médio, e, consequentemente, a área da abertura. Neste trabalho será descrito a metodologia para o calculo da incerteza de medição associada a este tipo de metodologia.

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Uncertainty evaluation in non-contact aperture area measurements

Abstract: A non-contact technique associated with a circle least-squares method allows one to determine the areas of the apertures used in radiometric and photometric measurements. Uncertainty evaluation in these non-contact aperture area measurements is presented.

Cited by 9 publications

References 6 publications

Optical aperture area determination for accurate illuminance and luminous efficacy measurements of LED lamps

Optical aperture area determination for accurate illuminance and luminous efficacy measurements of LED lamps

Étalonnage de la sensibilité en éclairement de radiomètres par la méthode de balayage de faisceau

Determinação da Incerteza de Medição na Calibração da Área de Aberturas Circulares

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