What should we pay special attention to the following issues in LED lighting photoelectric measurement at present?

First of all, the measurement standard
Light-emitting diodes (leds) of optical radiation is actually a kind of directional beam, so not in accordance with the general rules of photometric measurement and calculation of luminous intensity in the textbook. That is to say, usually a luminous intensity cannot simply be used to detect intensity of illumination and distance on the surface of the inverse square law to calculate. CIE127-1997 "light emitting diode measuring the intensity of the publications of LED testing identified as the concept of average intensity, and the provisions of a unified test structure, including the detector size and measure the distance of the request. This comparison lays the foundation for the LED the accuracy of the test. While CIE files are not international standards, but it has been generally recognized by the international and adoption. China's LED street lighting industry standards are in complete accord with the method of CIE file.
Second, the spectral response of the photometric measurement sensors
At present, in the LED photometric measurement sensor is used in measuring instrument adopts the silicon photoelectric diode and the corresponding visual spectral response of calibration filter. In order to make the probe of the spectral response function and CIE standard observer spectral luminous efficiency function V (lambda), usually consists of multiple filter. Due to the limitation of material and process, some instrument sensor exist certain differences in spectral matching, the instrument is used in the factory calibration standard source (usually adopt 2856 k to tungsten) and by measuring the spectra of the LED tube is put in bigger difference, the measurement of LED luminosity values can produce obvious deviation, and for some monochrome leds are often more obvious. Therefore spectral response curve should be used in various wavelengths fit better precision photometric detector, or using the method of spectral radiation measurement, and the weighted integral by a computer, get accurate measurement results. Otherwise, LED standard must be used here to calibration or calibration of instruments, to get more consistent results.
Third, the direction of the measurement

Light-emitting diodes (leds) launch the direction of the light is very strong, to measure the direction of the positioning will significantly affect the accuracy of the measurement results. Especially in LED the axial intensity measurement, some instrument for measuring the direction of the LED does not do is limited, so it is difficult to guarantee the accuracy of measurement. In the LED test power supply driver, the rise of junction temperature of LED itself to the influence of electric parameters and glowing nots allow to ignore. Therefore, environmental temperature and components of the measurement of the temperature balance is very important for measuring conditions. From the point of the domestic and foreign existing LED testing instrument, basically is the testing requirements for light emitting diode. With the development of the power type LED, the requirement for the unification of the test methods and instruments, more and more attention by all of us. Many of the existing test equipment, measurement for lighting LED lights will bring many new problems. Therefore, in the choose and buy and use the LED in the process of measuring instrument, must according to the types of products, features and relevant standards at home and abroad.
With the rapid development of LED industry, the industry should be according to the requirements of the LED street lighting products in different stage, formulate unified and standard test method as soon as possible, conform to the actual demand, with China's independent intellectual property rights of testing instrument, which is advantageous to the downstream industry chain, which cooperate with each other and coordinated development, promote the lighting LED the norms of the market and improve the Chinese enterprises to participate in the international market competitiveness. It is important to note that testing instrument is the product quality analysis and judgment of leverage, the accuracy and reliability of the instrument should be the most important indicator. Instrument manufacturing enterprise, China should develop more advanced international testing instrument, meet the needs of LED lighting industry development.

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