RESUMEN
Based on emission spectra of light sources and reflectivity curve of retroreflective materials, relative relations and changing trend of retroreflection coefficient of materials in different light sources was researched through data fitting. The tests were carried on the standard A light source test system. One kind of test results are emission spectra of halogen light source, xenon light source and white LED with different color temperature. And another kind of results are reflectivity curve of retroreflective materials with five different colors such as red, yellow, white, green and blue. Then the correction factors of retroreflection coefficient in different light sources were obtained by test results and data fitting. It shows that the change inlight source spectra has no effect on retroreflection coefficient of white material, which has continuous reflectivity curve in the range of visible light, but has some effect on retroreflection coefficient of the other color materials. Compared with halogen light source, white LED and xenon light source can increase retroreflection coefficient of red and yellow materials, and the increase in the color temperature of light source will decrease retroreflection coefficient of red and yellow materials by the maximum of 47.7% and 4.9%. Conversely, retroreflection coefficient of green and blue materials will increase by the maximum of 16.5% and 28.9%.
RESUMEN
Based on the MOVE models and the measurement of emission spectra of various light sources, the photopic function weights x and the mesopic equivalent brightness of human visual spectral luminous efficiency in different background brightness were calculated. Results showed that in the mesopic scope, human visual function peak value gradually increases with the brightness decreasing, and is moving towards the short-wave direction. The change rate is inversely proportional to the s/p index. In the case of ambient brightness for 0.5 cd X m(-2), peak values increase by 30% compared to the photopic function. Compared to the traditional test results, the mesopic equivalent brightness of fluorescent lamp and other different color temperature white light LED showed a positive gain that reaches 40%. On the other hand, the high pressure sodium lamp showed a negative gain. Results also showed that there was a decreasing trend when the ambient light level increased, and once the brightness level reaches that when cone cells play a full role, the equivalent brightness will equal photopic brightness. The methods and conclusions of this paper can help evaluate light sources, light-emitting material spectrum and characteristics of apparent brightness.
