Common lighting terms

Name                  Symbol                Unit                Description

Luminous flux          Φ              lumens lm            The total amount of light emitted by the luminous body per second is the amount of light emitted. All luminous objects indicate their brightness in terms of luminous flux

Brightness               L                     cd/㎡               Brightness refers to the brightness of a surface seen by the observer.

Light intensity          I                Candela cd           The luminous flux emitted by the luminous body in a specific direction per unit area

Illuminance             E                     lux lx                refers to the ratio coefficient of luminous flux to the illuminated area, that is, the luminous flux of the luminous body illuminating the unit area of the illuminated object, that is, the brightness of 1LM distributed on 1㎡.

Average life            H                   hours                   Refers to the number of hours when 50% of a batch of light sources are damaged

Color temperature   K                  Kelvin                 When the color temperature is below 3000K, the light color starts to appear reddish, giving people a warm feeling. The color temperature is more than 5000K, and the color tends to be blue, giving people a cool feeling. In the middle, it feels more moderate.

Color rendering Ra

The degree to which the light source presents the color of an object is called color rendering, which is the degree of color fidelity. Light sources with high color rendering have better color reproduction, and the colors we see are closer to the natural primary colors. Light sources with low color rendering have poor color reproduction, and the color deviations we see are also larger.

Glare TI

Objects with extremely high brightness or too strong brightness contrast in the field of view can cause visual discomfort, which is called glare. Divided into disability glare and uncomfortable glare, glare is an important factor affecting quality. When the glare is high, the visibility decreases, and when the glare is reduced, the visibility increases.

Light source efficiency Lm/W Light source efficiency (Lm/w) = Lumens (Lm)/Power consumption (w)

Illumination uniformity The dark area on the illuminated object will reduce the visibility of the target, so the illuminated object is good

The uniformity of the illumination is very important.

Visually guided car drivers must receive information about the direction of the road or building ahead in order to react in time. This item should be considered when designing lighting to ensure traffic safety.

Environmental factor SR To ensure that road users can see obstacles more clearly, the surrounding environment of the road also needs to have a certain brightness.

Artistic beauty and

Comfort The artistic beauty and comfort of outdoor lighting play an increasingly important role in highlighting the urban function and environment. As a soft indicator, it reflects the artistic added value of outdoor lighting and the connotation and foundation of urban cultural construction functions.