对于天然采光显色能力的探讨(英文)

APPROACH TO THE COLOUR RENDERING PERFORMANCE OF DAYLIGHT

众所周知，天然光在不同的时间、气候等条件下，其光度和色度都有所差异，其中对光度已进行过许多研究，但对其显色能力还研究不足。为此我们在西安地区对几种天空光源的色度情况作了调查。调查结果表明天空扩散光相关色温与当中无遮挡水平面照度的关系是不显著的。在早晚或阴晦天气下地平面照度在１０００１ｘ以下时，色温较高，可达１３０００ｋ以上，而在白天的其它时间内（照度变化范围在１０００～２００００１ｘ之间），色温的波动范围在４０００～７５００ｋ之间。若取天然光的临界照度为４０００１ｘ，则其色温变化不会越出这个范围。 结果还表明天空扩散光的色温近似地沿着普朗克幅射轨迹散布着。

In different weather and time of a day, the illuminance and chromaticity or skylight in city Xian were measured. It shows that the relation between the illuminance and colour temperature is not striking. In order to make a better comparison, D 5500 and D 6500 were taken as reference light sources to compare the colour effect of sunlight. Results show, the CIE colour rendering indexes, derived by assuming a series of numerous reference light sources are only a rough estimation. A more effective index should be derived on the basis of a more accurate comparison.