Calculation of luminous flux output of axisymmetric lamps

Abstract: This paper discusses a simple method for calculating the luminous flux output of axisymmetric lamps and gives an example.
Keywords: luminaire; luminous flux output; luminaire efficiency; light intensity; light distribution curve.

1 Introduction

Based on the data of the light distribution curve, it is a basic problem in the illumination analysis to calculate the luminous flux output of the luminaire and to obtain the luminaire efficiency. This paper attempts to find a simple, feasible, accurate and practical method for calculating the luminous flux output.

2 fitting of the light distribution curve of the lamp

The light distribution curve (ie, the light intensity distribution curve) is a visual representation of the luminaire's illuminating performance and illuminating form, and plays an important role in luminaire design and manufacturing, as well as lighting engineering. It generally has two forms of polar coordinates and rectangular coordinates. The two light distribution curves of a luminaire are shown in Figures 1 and 2.

Figure 1 Polar coordinate form light distribution curve

Figure 2 Right angle coordinate form light distribution curve

Obviously, the light intensity value I is a function of the space spherical coordinate latitude and the two angles, that is, I=I . The expression ^[1] of the luminous flux output is thus: