Research On Test Method Of LED Light Source Parameters In High Temperature Environment

With the increasing demand for industrial applications of UV(ultraviolet)light source,high-power ultraviolet LED light sources are widely used in the market.Due to the high energy density and high heat generation of the high-power ultraviolet LED light source,the ambient temperature is high.The research object in this paper is the UVLED light source used in industrial UV curing oven.In order to make the related UV applications such as screen printing,PCB coating and curing better,it is necessary to measure the parameters of LED light source,while some conventional electronic measuring instruments can not be well applied in the above high temperature environment.In this paper,a series of testing methods for the parameters of ultraviolet LED light source at high temperature are studied.Based on the principle of optical fiber transmission and photoelectric detection,optical fiber is used as the carrier of light transmission,photodiode is used as the detection sensor,and the structure of ARM realizes the accurate measurement and analysis of the parameters of LED light source.Aimming at the situation that the temperature of UVLED light source is too high to be detected routinely in the curing process,a scheme using optical fiber to guide light is proposed.Ultraviolet quartz fibers coated with high temperature resistant polyimide can effectively transmit the commonly used ultraviolet bands in curing process.The front-end light source receiving probe is designed into different styles according to the type of light source,and the optical simulation software is used to qualitatively analyze the parameter characteristics of optical fiber and optical receiver,so as to reduce the loss of light source in the transmission process and improve the coupling efficiency of optical fiber.In view of the fact that the above optical fibers will lose a lot of light energy in the process of light guide and transmit to the ultraviolet photodiode with low light intensity,In this paper,the weak optical signal acquisition is improved on the traditional processing mode,and the dual acquisition mode of current integration pulse acquisition and high-precision voltage acquisition fusion is realized,and the ultraviolet power density(light radiation illuminance)and light energy parameters are collected.Analyze the traditional photoelectric acquisition circuit and make optimization and improvement,improve the precision,and cooperate with the integrated pulse acquisition method to realize the dual acquisition method of low-power mode and high-precision mode fusion through configuration,and reasonably avoid the shortcomings of the two methods.The LED array light source is composed of a combination of lamp bead strings.After long time working in a high temperature environment,the lamp bead aging will be damaged,resulting in a decrease in the overall power.In order to detect the above situation of the light source during use,an accurate method is proposed.Based on the detection of conventional transformers,this paper adds a professional power chip to detect the power of LED driving light source.Using this method combined with good PCB layout and soldering can increase the accuracy of the collected electrical power to within 3%.At the end of this paper,this paper explores the problem of light decay life of LED light source under long-term working conditions.Stress acceleration and long-term testing of ultraviolet LED light source are carried out.The attenuation is checked with the parameters of light power density as the measurement index,and compared with conventional UV light tube.In order to improve the reliability and security of the test process,the software over-temperature protection mechanism and the hardware overcurrent protection mechanism are designed.Through the above test methods,the electric power,optical power density,optical energy and optical decay parameters of LED light source can be measured and analyzed perfectly.