Comparative Research On Different Cellphone Screens Biological Effect Of Lighting

With the development of lighting technology,the fourth generation of new light source LED(Lighting Emitting Diode)has more advantages than previous generations of traditional light source lighting products such as energy saving,long life,environmental protection,high efficiency and low price.Because these characteristics,LED is widely applied to urban road lighting,traffic lights,vehicle lights,indoor lighting,self-illuminating electronic products and other fields.At the same time,the research on non-visual photobiological effects is constantly attracting people's attention and the research focus has gradually shifted from the initial theoretical research to the physiology and mental health issuas related to self-luminous products.The content of this paper is divided into two parts.The first part researches on the influence of the three normal different material cellphone screens(LED backlight LCD,OLED,SUPER AMOLED)on adolescents circadian factor and blue light hazard in dark on condition that the distance of cellphones screen from pupil is 15 cm and four different color temperature.With the age,area of eye light exposure and transmittance being considered,the calculating formula of blue light hazard factor is upgraded.Circadian factor and blue light hazard factor is also calculated.It's shown that circadian factor and blue light hazard factor increase with the increase of color temperature and strong linear relation is also exist.When color temperature is between 7425 K and 9201 K,circadian factor ranked from high to low follow: OLED,SUPER AMOLED,LED backlight LCD.Blue light hazard factor ranked from high to low follow: LED backlight LCD,SUPER AMOLED,OLED.As a result,according to different requirement,a healthy and suitable cellphone can be chosen.The second part is to show the influences of four different light environments(3000K,4000 K,6000K,dark)on the non-visual photobiological effects of human.We analyze four different light spectral distributions.Circadian factor M values are calculated to theoretical compare the non-visual biological effect of four different ambient light environments.We measure the systolic pressure,diastolic pressure and heart rate of volunteers with four different light environments.These physiological parameters are applied to characterize the level of non-visual biological effects,the theory and experiment are mutually demonstrated.The theoretical result shows that the higher M values are derived with cellphone bright screen in the dark.M values decrease with the decrease of ambient light environment color temperature.The experimental results show that systolic pressure,diastolic pressure and heart rate change rate decrease with the increase of ambient light environment color temperature.Besides,it is shown that using mobile phones in the dark will have a stronger non-visual biological effect and have an adverse impact on nocturnal sleep and circadian rhythm.We can decrease for the damage to a some extent by appropriately decreasing external color temperature of white light.