For Led Testing Small Two-dimensional Horizontal Distribution Photometer System

It is well-known that LED, a device with many advantages such as energy saving, environmental protection, long life-span and etc, is going to be a new and general type of light source and has immensely capacious prospects in the field of lighting. Among the many technical indexes of LED, the total luminous flux is one of the most important. With the continuous development of LED industry, an accurate measurement on the total luminous flux of LED has been put on the agenda. Currently one popular LED luminous flux measurement approach is to adopt the traditional integrator relative measurement, however, when used for measuring such kind of new type of light source with narrow light beam as LED, it shows its greatest drawbacks, namely, it produces serious measurement errors. This paper introduces a mintype horizontal distribution spectropho—tometer system developed by the author, which is used for measuring the luminous flux of LED on the basis of the absolute measurement approach and can avoid the said drawbacks produced by integrator relative measurement approach. During the development of the system, an ingenious blend of the respective advantages of VC++6.0 MITSUBISHI FX1N PLC and MATLAB7. 0 has been made to make the system performs satisfactorily as well as to keep the results of measurement as accurate as possible, this attempt smoothly solves the following problems of the real time communication and the co-operative programme between VC++6. 0 and MITSUBISHI FX1N PLC, as well as the mixed programme between VC++6. 0 and MATLAB7. 0, making the best blend of the above three in the system. Judging from the data and results of the measurement on LED samples, this system has reached a good state in various aspects of performances and has achieved the desired results.