Integrating Sphere Simulation on Spatial Nonuniformity Errors in Luminous Flux Measurement

Published

January 1, 2001

Author(s)

Yoshihiro Ohno, R O. Daubach

Abstract

An integrating sphere simulation program, previously developed for the realization of the luminous flux unit at NIST, has been utilized to analyze spatial nonuniformity errors in integrating sphere photometers for substitution measurement of total luminous flux of lamps. The program simulates interreflections in an integrating sphere and calculates the final luminance distributions on the sphere wall as well as the detector output. Using this program, a series of simulations has been conducted on a 2 m integrating sphere having a 30 cm circular baffle, with varied sphere wall reflectance (p = 80 % to 98 %) and baffle reflectances, the size and location of the baffle, and the angular response of the detector. Measurement errors (with respect to an isotropic point source) were calculated for actual intensity distribution data of eight different types of incandescent and discharge lamps. The results show that, with a well-designed integrating sphere photometer with no contamination of coating, measurement uncertainties (k = 2) on the order of 1 % (p = 80 %) to 0.1 % (p = 98 %) can be expected for typical general service lamps with no reflectors, measured against a calibration source of uniform intensity distribution. Larger errors are shown with integrating sphere systems not properly designed.

Proceedings Title

Proceedings for IESNA Annual Conference

Volume

30

Issue

No. 1

Conference Dates

July 31-August 2, 2000

Conference Title

Journal of the Illuminating Engineering Society

Pub Type

Conferences

Keywords

calibration, goniophotometry, integrating sphere, lumen, luminous flux, photometer, sphere photometry

Citation

Ohno, Y. and Daubach, R. (2001), Integrating Sphere Simulation on Spatial Nonuniformity Errors in Luminous Flux Measurement, Proceedings for IESNA Annual Conference (Accessed March 13, 2025)