Learn the little knowledge of lighting

Update:07 Sep 2020
Summary:

brightness The luminous intensity of a luminous body on […]

brightness
The luminous intensity of a luminous body on a unit projected area in a given direction is called luminance, expressed in L,
Unit: candela. Per square meter. (Cd/㎡)
The luminance of the illuminant in the direction of θ is
L=Iθ/Scosθ
The brightness of the object surface is related to the intensity of the light source and the reflection ability of the object.
Color temperature
When the color of the light source is the same as that of the blackbody heated to a certain temperature, it is called the color temperature of the light source.

Conversion relationship
1 lux = luminous flux of 1 lumen evenly distributed over an area of 1 square meter
1 lumen = luminous flux emitted in unit solid angle by a point light source with a luminous intensity of 1 candela
1 lux = illuminance produced by a point light source with a luminous intensity of 1 candela on a sphere with a radius of 1 m
Cold light source
Light source excited by chemical energy and electric energy, such as LED, El, energy saving lamp, optical fiber, fluorescent lamp, etc.
Thermal light source
Light source excited by heat energy, such as incandescent lamp, halogen lamp, high pressure mercury lamp, metal halogen lamp, etc.

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