Research On Key Technology Of LED Health Lighting Based On Pulse Drive

Lighting is closely related to people’s life.Lighting has a great influence on people’s visual characteristics,including visual discrimination and visual comfort,and non-visual characteristics,including physiology and psychology.Due to the short and easy-control switch time of LED,the actual application of LED often use PWM to adjust the light.When LED works in pulse state,it will cause stroboscopic to a certain extent.The light that exceeds the specific stroboscopic index has adverse effects on human physiology and psychology,but it can improve the perceived brightness of human eyes.There is a certain contradictory relationship between the light generated by the pulse driven LED and the human body’s visual and non-visual effects,so it is of great significance to study the PWM dimming mode of the LED driving on the human body.By analyzing the influence of the light driven by many kinds of pulse parameters on human body and balancing the influence of pulse light on human vision and non-vision,the optimal condition based on health lighting is obtained.Health lighting mainly involves stroboscopic effect and spectral quality,which have an important impact on human physiology and psychology.The history of human evolution determines that people’s eyes and life are accustomed to sunlight.The solar spectrum has a relatively average spectral power distribution in the range of 400 nm to 760 nm visible to the human eye,which is known as the all-optical spectrum.The spectrum quality of single-chip LED lamp is low,which presents a small wavelength spectrum according to different color temperature characteristics,while the spectrum power distribution of other bands is seriously missing.For a long time under the low spectral quality LED light,the human eye will produce dry,painful and other symptoms,and even induce myopia.At the same time,the physiology of human blood pressure,heart rate and so on will also have adverse changes.Therefore,different spectral assembly methods to simulate the whole spectrum came into being,but the ghosting brought by the spectral assembly of multi-chip integration cannot be ignored.This paper studies the effects of LED working in PWM pulse state on human visual recognition,visual comfort,and human physiology and psychology.An optimized PWM dimming mode was obtained and then applied to a full-spectrum luminaire to further study the effect of full-spectrum illumination on human body.The main research contents are as follows:1.This paper introduces the basic principle of LED and the dimming mode of LED lamps.By comparing the advantages and disadvantages of different technical parameters and dimming mode,a better dimming mode was obtained to produce pulsed light.2.Investigating a large number of literatures,including the human visual system,the effect of photoreceptor cells and the spectral luminous efficiency function.The relationship between light,human eyes and human physiology was analyzed.3.The reasonable experiment plan was made,and four kinds of experimental measurement indexes and evaluation indexes were designed.A function generator was used to generate the preset pulses of 24 different parameters and a set of Direct Current comparison groups for driving LED lamps.The heart rate,blood pressure,visual comfort and visual recognition were measured and recorded.For the first time,the time correction method and the difference method were proposed,and the modified proportional was 23.6%.SPSS 22.0 software was used to analyze the significance and correlation between the experimental groups.The experimental results show that when the frequency is 300 Hz and700 Hz,and the duty ratio is higher than 60%,the influence of light on human body is better,and the optimized pulse parameters are obtained.4.Based on the pulse parameters obtained from the third point above,it is used to drive the spectral assembled full spectrum lamps and common spectrum lamps.12 kinds of wavelength beads were combined to simulate the solar spectrum with ORIGIN 9.0 and MATLAB R2018 b software,and the feasibility of the module was verified by the ghost test.Based on the comparative analysis of heart rate,blood pressure,visual comfort and visual discrimination,it is found that full spectrum lamps are healthier than common spectrum lamps.The results provide important reference for the further study of lighting and human health.