Explanation of common terms for light meters
Definition of mcd, lumen tile, illumination
"Lumen tile": The energy emitted by the light source into the space per unit time to make people feel light is called "luminous flux", and its unit is "lumen". "Lumen watt" is the pronunciation of "lumen/watt", which refers to the ratio of the luminous flux emitted by the light source and the electrical power it consumes, that is, the luminous efficiency of the light source.
"mcd": The spatial density of luminous flux, that is, the luminous flux per unit solid angle, is called luminous intensity. It is a measure of the intensity of the light source. Its Chinese name is "candela" and its symbol is "cd". The "m" in front is the prefix, which means one thousandth (just like the unit of length, the Chinese name is "meter", its symbol is "m", add another "m" in front to become "mm", it becomes One thousandth of a meter, which is a millimeter), so the Chinese pronunciation of "mcd" is "millicandela".
"Illuminance: refers to the luminous flux passing through an object illuminated by a light source per unit area. In layman's terms, it is the degree to which the object is illuminated. The unit is "lux" and its symbol is "Lx
Long-wave ultraviolet (UVA): wavelength 400~320nm, its biological effect is weak, it has obvious pigmentation effect, and its effect on causing erythema reaction is very weak. It can cause some substances (fluorescein sodium, tetracycline, quinine sulfate, hematoporphyrin , pyocyanin from Pseudomonas aeruginosa and substances produced by some molds, etc.) produce fluorescent reactions. It can also cause phototoxic reactions and photoallergic reactions. Mid-wave ultraviolet (UVB): wavelength 320~275nm, which is the most active part of ultraviolet biological effects. The erythema reaction is very powerful, converting provitamin D into vitamin D, promoting epithelial cell growth and melanin production, and inhibiting allergic reactions. Short-wave ultraviolet light (UVC): wavelength 275~180nm, has obvious erythema reaction effect, and has obvious killing and inhibiting effects on bacteria and viruses
