Color temperature (Kelvin) 

refers to the color change that the human eye can perceive under different energies of light waves. It is used to indicate the scale of the light color of the light source. The unit is K. The measurement method is based on black body radiation 0. Kelvin=Celsius -273°C is the starting point for calculation. When heating the black body, as the energy increases, it will enter the field of visible light. For example, at 2800K, the color light emitted is the same as that of a light bulb. Let's say that the color temperature of the light plate is 2800K. The color temperature change in the visible light field is from low color temperature to high color temperature from orange to red to white to blue. From 'The Ultimate Bible of Lighting Design'

Luminous flux (Luminous flux)

 simply means the energy of visible light, refers to the unit time, emitted by a light source and perceived by the human eye The sum of all radiant energy emitted and perceived by the human eye can again become a beam (ϕ), and its unit is Lumen (Lm). The sum of all the radiant energy taken from the 'Ultimate Lighting Design Bible' can also become a light beam (ϕ), and its unit is Lumen (Lm). From 'The Ultimate Bible of Lighting Design’

Illumination (IIIuminance)

 refers to the number of lumens per unit area of the illuminated surface, the unit is Lux, 1Lux=1 lumens/square meter, we often say that the reading desktop is bright enough, usually refers to the illuminance enough. If the same area is the unit, the higher the luminous flux of the light source, the higher the lumen value, the higher the illuminance. Generally speaking, if the working environment is required to be bright and clear, the illuminance requirements are higher. For example, the general lighting brightness of the entire study room is about 100 Lux, but the local accent lighting during reading needs to be at least 600 Lux. Therefore, table lamps can be used as local lighting fixtures. Calculating the illuminance formula N = number of lighting fixtures F = the luminous flux (Lm) of the lamps used U = illuminance rate (will vary with the reflectivity of the ceiling, wall, ground, etc., the length, width of the room and the height of the light source also affect the illuminance rate Major factors). M=Maintenance rate (The maintenance factor varies according to the structure of the lighting equipment and the degree of indoor pollution. In places that are easy to clean and less polluting, the maintenance rate is high; on the contrary, the maintenance rate is low in places that are difficult to clean and highly polluting. Maintenance The rate generally goes between 0.6~0.8). A=Indoor area (㎡) from 'The Ultimate Bible of Lighting Design'