基于视觉功效法的公路照明光源性能分析

The Performance Analysis for Lighting Sources in Highway Tunnel Based on Visual Function

中间视觉条件下人眼光谱效率函数表现为一系列的曲线,其峰值波长和强度受光源光谱、背景亮度等多方面的影响,光源对照明视认性的影响无法通过单一的光学参量进行表征。试验以视认反应时间作为评价指标,应用视觉功效法测试了不同速度条件下,人眼在不同照明环境中的视认性能,所选择光源包括高压钠灯、无极荧光灯和三种色温的白光LED,光源色温范围1 958~5 537K,背景亮度取值针对公路隧道基本段照明和一般室外道路照明,范围为1~5cd·m^-2,均在人眼中间视觉亮度范围内。统计试验结果显示：在相同速度、亮度条件下,高色温光源对应的视认反应时间小于低色温光源;相同亮度条件下高速视标对应的反应时间小于低速视标,但测试截止时刻,低速视标在观察者视场内的张角较高速视标更大。应用MOVE模型计算得到测试光源所形成不同发射光谱、不同背景亮度条件下的人眼中间视觉等效亮度,与明视觉亮度测试结果比较,中间视觉等效亮度对应的反应时间曲线标准差系数CV更小,显示中间视觉条件下不同光源等效亮度与明视觉亮度的差异是造成视认性差异的原因之一,由于白光LED光源的GaN芯片发射光谱峰值与中间视觉光谱效率函数的峰值波长较为接近,高色温白光LED的照明视认效果优于低色温白光LED和无极荧光灯,峰值位于Na＋特征谱线附近的高压钠灯照明视认效果较差。

Under the condition of mesopic vision ,the spectral luminous efficiency function is shown as a series of curves .Its peak wavelength and intensity are affected by light spectrum ,background brightness and other aspects .The impact of light source to lighting visibility could not be carried out via a single optical parametric characterization .The reaction time of visual cognition is regard as evaluating indexes in this experiment .Under the condition of different speed and luminous environment , testing visual cognition based on vision function method .The light sources include high pressure sodium ,electrodeless fluores‐cent lamp and white LED with three kinds of color temperature （the range of color temperature is from 1 958 to 5 537 K） .The background brightness value is used for basic section of highway tunnel illumination and general outdoor illumination ,its range is between 1 and 5 cd·m^-2 .All values are in the scope of mesopic vision .Test results show that：under the same condition of speed and luminance ,the reaction time of visual cognition that corresponding to high color temperature of light source is shorter than it corresponding to low color temperature;the reaction time corresponding to visual target in high speed is shorter than it in low speed .At the end moment ,however ,the visual angle of target in observer’s visual field that corresponding to low speed was larger than it corresponding to high speed .Based on MOVE model ,calculating the equivalent luminance of human mesopic vision ,which is on condition of different emission spectrum and background brightness that formed by test lighting sources . Compared with photopic vision result ,the standard deviation （CV） of time‐reaction curve corresponding to equivalent brightness of mesopic vision is smaller .Under the condition of mesopic vision ,the discrepancy between equivalent brightness of different lighting source and photopic vision ,that is one of the main reasons for causing the discrepancy of visual recognition .The emis‐sion spectrum peak of GaN chip is approximate to the wave length peak of efficiency function in photopic vision .The lighting vis‐ual effect of write LED in high color temperature is better than it in low color temperature and electrodeless fluorescent lamp . The lighting visual effect of high pressure sodium is weak .Because of its peak value is around the Na＋ characteristic spectra .