LED Light Output Efficiency 4 Hemispherical packaging LED light intensity distribution
The top of the so-called non-hemispherical packaging is still the hemisphere, however there is a piece of cylinder below, shown as figure 7, this shape is close to the real subject. At this time, the emergent light can be divided into two parts, one part is sent out from the top hemisphere, the other part [...]
Theories About Light Part1: Visible Light and Intensity
Intensity: The candela is the basic unit in photometry. All other luminous quantities can principally be derived from it. The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 Hertz and that has a radiant intensity in that direction of 1/683 Watt per Steradian. One steradian [...]
Photometric Terms
Luminous flux: Φ, Lm Luminous flux is the sum total of the amount of light per second generated by the illuminant. Light intensity: I, cd The luminous intensity is the luminous flux from a point source emitted per unit solid angle in a given direction. A goniophotometer can be used for measuring light intensity. Illuminance: [...]
