Lumen (Latin for ‘light’) is an optical measurement of the amount of light emitted from a source. It is commonly used to measure the amount of illumination given off by a light source such as a lamp or a light bulb. In the field of photometry, the lumen is a measure of the total amount of visible light emitted by a source per unit of time. The lumen is widely used in the measurement of light intensity and can be used to determine the brightness of a light source.
The lumen is defined as the amount of light emitted from a source in one second (1 lm/s). It is calculated by multiplying the luminous flux emitted by the source by the solid angle it is emitted over. The luminous flux is a measure of the total amount of light emitted by a source, and the solid angle is the area of the surface of a sphere that is illuminated by the source.
The lumen is a unit of measurement for both visible and invisible light. It is useful for quantifying the amount of light emitted from a source in a given area. For example, it can be used to measure the brightness of a light bulb or the intensity of a laser. It is also used to measure the amount of light reflected off of a surface.
The lumen is an important metric for lighting engineers, allowing them to accurately measure the amount of light emitted from a source. It is used to assess lighting levels in buildings, design lights for sports stadiums, and calculate the brightness of LED lighting. The lumen is also used in the calculation of the illumination of a given space, such as a room or a hallway, and can be used to determine the amount of light needed for a given task.
In conclusion, the lumen is an important metric for measuring light intensity and brightness. It is used to measure the amount of light emitted from a source in a given area and is used to assess lighting levels in buildings, design lights for sports stadiums, and calculate the brightness of LED lighting.
References
American National Standards Institute (2012). Illuminating Engineering Society of North America (IESNA): Lighting Handbook, 9th Ed. New York, NY: American National Standards Institute.
International Commission on Illumination (CIE) (2006). CIE Publication 15.2: Colorimetry, 2nd Ed. Vienna, Austria: International Commission on Illumination.
U.S. Department of Energy (2020). Lumen and Luminous Flux. Retrieved from https://www.energy.gov/eere/lighting/lumen-and-luminous-flux