Photometer for controlling the lighting parameters of LEDs

Abstract

According to DSTU CIE 127:2017, control of characteristics of light-emitting diodes can be carried out in the laboratories of industrial or operational institutions with the use of working standards of radiation sources checked in the certified laboratories. The advantages of mass control of photometric characteristics of radiation sources are the following: higher speed and lower cost at a slightly lower but acceptable accuracy. In order to carry out mass control that meets the above requirements, in terms of production and operation, methods and technical means with a fairly high productivity, low cost of measurements and sufficient accuracy are required. The aim of the work is to solve an urgent problem – to increase the accuracy of measuring the light parameters of LEDs with a concentrated spatial distribution of luminous intensity and luminous flux for photometers without the use of rotating devices. It is shown that a photometer based on standard digital cameras, using a fiber optic focus and a correcting light filter, can provide sufficient accuracy in measuring the spatial distribution of radiation from directional light sources. Due to the use of a focon and matrix discrete photodetectors located in a plane perpendicular to the axial direction of radiation, it is possible to obtain an angular spatial distribution of light source radiation without rotating devices, which in turn reduces the cost of testing. The characteristics and ease of operation of modern digital cameras have allowed their use as a photodetector array, which simplifies the design of the photometer. The error of measuring the characteristics of sources with concentrated types of curves of light using a photometer in comparison with goniophotometric methods does not exceed 5%, which allows the use of such photometers for rapid control of such products in mass production and operating conditions.