Array-based goniospectroradiometer for measurement of spectral radiant intensity and spectral total flux of light sources

Abstract

We present a description of a new goniospectroradiometric measurement system developed at the National Physical Laboratory (NPL). The instrument incorporates a modified array spectrometer and a series of rotary stages to allow measurement of the spectral radiant intensity distribution of a variety of different types of light source from 350 to 830 nm. Associated source properties such as chromaticity and correlated color temperature distributions and total spectral flux are then calculated from the radiant intensity data. A preliminary comparison with NPL's integrating sphere-based luminous flux scale shows agreement to within 0.4%, well within the combined measurement uncertainty. Measurements of the luminous intensity and color temperature distributions and the spectral total flux of a tungsten filament flux standard, a white LED cluster and a compact fluorescent source made using the goniospectroradiometer, are also presented.

Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

“…In order to perform reliable solar UV measurements, a specific measurement scenario, the so-called solar bandpass correction method, was used. This measurement scenario is based on a series of measurements with several narrow-bandpass filters which complement each other (Shaw and Goodman, 2008). Hence, the overall measurement time to get a full spectral measurement is the sum of all integration times of the sub-measurements.…”

Stray light correction of array spectroradiometer measurement in ultraviolet

“…Since compact array spectroradiometer has a fast acquisition speed and is portable, it is widely used in photometric and radiometric measurement in recent years. The characteristic of the array spectroradiometer was investigated during the past ten years, such as the bandwidth, the stability and the stray light [1][2][3][4][5][6][7][8][9]. However, report on the UV spectroradiometer application in direct use is not much due to the significant stray light in UV band.…”

“…Feldman has implemented a digital micromirror device in array spectroradiometer to reduce the stray light [6]. Shaw has investigated the stray light of array spectrometers using a series of cut-on filters [7]. Compared to the tunable laser method, the filter method is much cheaper and can save a lot of time.…”

Construction of Two-Axis Goniophotometer for Measurement of Spatial Distribution of a Light Source and Calculation of Luminous Flux

“…Floodlights, projectors, automobile headlights and other concentrating beams should be tested at much greater distances than those of indoor luminaires. For this purposes a mirror-type goniophotometer, in which one or two mirrors are located for sending the light to the photometer head is the best solution for defeating the restrictions arising from too large distances necessary to make measurements suited in the measurement conditions specified above in laboratory situation [6,7].…”