| Luminous flux The amount of light passing through a unit of time, in lumens (lm) Luminous flux Φ lm (lumens) The amount of light passing through unit time. Light intensity The luminous flux emitted by a light source and contained within a unit solid angle in a given direction, in sill, cd. Light intensity I = Φ/Ω (cd candela) Ω solid angle Brightness L=I/(S.COSθ)cd /m2 Illuminance E=Φ/S Illuminance measurement: 85cm on the ground when standing, 40cm when sitting brightness Refers to the ratio of the luminous intensity of the light-emitting surface in the specified direction to the projected area of the light-emitting surface on the plane perpendicular to the selected direction, in units (cd/m2). Illumination Illuminance is the luminous flux received per unit area of the illuminated surface, and the unit is lux (lx). The light efficiency coefficient of the light source The luminous flux that a light source (lamp) consumes 1W of power can produce, in lm/W. |