照度科学

照度是入射到表面上的总光通量除以单位面积。它是衡量入射光照亮表面程度的指标，按波长通过亮度函数加权，以与人类亮度感知相关联。

介绍

Illuminance quantifies how much light falls on a surface, which is crucial for lighting design, photography, and ensuring adequate visibility in various environments.

历史

The study of illuminance developed with photometry in the 18th century. The lux unit was established as part of the metric system, and modern illuminance measurements became standardized with the development of photometric standards.

关键单位

Lux (lx)

The SI unit of illuminance, equal to one lumen per square meter.

Foot-candle (fc)

An imperial unit equal to one lumen per square foot, approximately 10.76 lux.

Phot (ph)

A CGS unit equal to 10,000 lux, rarely used today.

应用

  • Architectural and interior lighting design
  • Photography and cinematography
  • Workplace safety and ergonomics
  • Plant growth and horticulture
  • Street and outdoor lighting standards

Illuminance Calculation

E = Φ/A = I·cos(θ)/r²

Illuminance equals luminous flux divided by area, or luminous intensity times cosine of angle divided by distance squared.