Relationship between luminous intensity and distance of LED
Luminance is the intensity index of light emitted by the two light source from the light source and the reflector and transmission surface to the observer. The unit is cd/m2. Like luminous flux, it is a physical quantity that is expressed by the sensitivity of human eyes. Mostly used when indicating brightness of LCD panel and PDP display screen.
Illuminance is the luminance indicator of the light that irradiates the plane. The unit is LX (Lux), sometimes labeled as lm/m2. Refers to the luminous flux of a light source to a flat object, the luminous flux per unit area. Used to compare the brightness of a luminaire to a plane.
Light intensity is the index of luminous flux, solid angle density. The unit is cd. Mostly used when showing glare such as LED. It is defined as: emitting 540 * 1012Hz (wavelength 555nm) frequency monochromatic light, in the specified direction of light emission intensity of 1/683W/sr light source, in that direction the light intensity is defined as 1cd.
The luminous flux of LED is an indicator of the overall brightness of the light source. The unit is LM (Liu Ming). Often used when illuminating the brightness of a light source. A physical quantity that represents the luminance of a light source, referring to the sensitivity of the human eye (visual sensitivity). The specific value is isotropic. The luminous intensity is 1CD (LA), and the luminous flux in the solid angle of 1sr is 1lm. Where SR is the solid angle of the unit, said from the center area of the ball for the interception of the radius (R) of 2 times (R2) of the cone angles.
