On-line Measurement System For Light Distribution Parameters Of Light Source

A good lighting design can create a favorable visual environment for the users. It can not only help to improve the comfort and safety, but also save energy of lighting through the reasonable light distribution. The spatial light distribution characteristic of the source is the basis of lighting design and the key premise to achieve design effect. At present, solid-state lighting occupies the mainstream market gradually. Due to the complexity of the production process of the solid-state light source, there are some problems of the consistency of the space light distribution parameters. However, the products with light distribution problems cannot be screened out timely before they leave the factory due to the lack of fast in-line measuring equipment. Aiming at this problem, this paper provides a design of a set of measurement equipment for fast spatial light distribution testing.The measurement equipment includes a fast acquisition module of optical information and a photoelectric conversion module. The information of light distribution can be collected through one ends of optical fibers arranged on a hemisphere frame. These optical fibers are also used as the light transmission medium. Then, the light information will be converted at the other ends of the optical fibers with a linear photoelectric sensor which is widely applied in scanners. The corresponding device driver and data acquisition program are provided. Based on the hardware, the system performance is analyzed in detail. The theory models for optical information transmission and conversion are deduced with and without system errors. The data treatment method has been put forward, in which the measured data with our system are corrected with data obtained from standard measurements. Then, the light intensities at the end of optical fibers on the frame can be calculated.Based on the above design, a prototype of the fast measurement equipment of space light distribution has been constructed. The light distribution parameters are tested for normal LED samples and polluted and scratched samples with abnormal light distributions. Results show that the prototype can screen out products with abnormal light distribution parameters, which can be used for real-time testing of light source products. In addition, the absolute value of light distribution parameters measurement is studied with the prototype. Due to the difference of spectrum response, it exists the limitations for measurement of the absolute value of light distribution with the prototype.