Optical Terms

1. Luminous flux

Luminous flux  refers to the radiant power that the human eye can feel, which is equal to the product of the radiation energy of a certain band of time and the relative viewing rate of the band. Because the human eye The relative viewing ratios of different wavelengths of light are different, so when the radiated power of different wavelengths of light is equal, the luminous flux is not equal.

2.Light intensity

The luminous flux (Im) emitted by a luminophore in a unit of solid angle in a particular direction, in candelas mcd. The international unit is candela (abbreviation cd), which refers to the light of a monochromatic light source (frequency 540×10 12 Hz, wavelength 0.550 μm) in a given direction (radial intensity in this direction is (1/683) watts/sphericity)) The luminous intensity emitted within the solid angle of the unit.


Luminosity refers to the degree to which an object is illuminated. It is expressed in terms of the luminous flux received per unit area. The unit is Lux, lx, or lm/m2. 1 Lux is equal to 1 Lumen (lm) The luminous flux is evenly distributed over an area of ​​1 m2. Illuminance is based on the luminous flux received in the vertical plane.

4.Color temperature

When a standard blackbody (such as iron) is heated, the temperature begins to change from red->light-red->orange->white->blue-white->blue to a certain degree. The color gradually changes. When the light color of a light source is the same as the light color of a black body at a certain temperature, we call the absolute warmth of the black body at that time the color temperature of the light source, in K.

CCT change


The change in the color of light can be described by data, which is called wavelength. The unit is nm. Visible light has a wavelength in the range of 380-780 nm.
• Red: 630-780nm Orange: 600-630nm Yellow: 570-600nm
• Green: 500-570nm Blue: 470-500nm
• Blue: 420-470nm Purple: 380-420nm

led waves

6.Light effect

The ability of an electric light source to convert electrical energy into light, expressed as the luminous flux emitted divided by the amount of electricity consumed, in lumens per watt (Lm/w).

7.Color rendering

The degree to which a light source presents its color is called color rendering and is usually called the color rendering index (Ra). The degree of the light source’s appearance of the object’s color is called color rendering, which is the fidelity of the color. The light source with high color rendering is better in reproducing the color, and the color we see is closer to the natural color, and the color rendering is low. The light source has poor reproduction of colors, and the color deviation we see is also large

Optical Terms



Quality is our priority & Customer is the first

Our Work

Dayup’s LED Tape Light has been one of the leading suppliers of high power LED lighting in China.

Our products :  Flexible LED Strip lightLED Panel LightLED downlightLED Linear LightLED Neon flexLED Aluminum ProfileLED ControllerLED Power Supply.

Why Us

Dayup’s range of lighting integrates energy-saving , Eco-friendly ,decoration and many other innovative features. All products undergo rigorous testing during the development and manufacturing process and before leaving the factories.

With clear marketing orientation, sustained technical innovation and internationally-updated management philosophy, Dayup has built a good reputation at home and abroad with top quality products , advanced lighting solution and cheerful after-sales service .

Contact Your Account Sales Today

Telephone : +86 755- 2308 9165

Mailto: sales@dayup-lighting.com

Follow us on LinkedIn!


About the Author:

Leave A Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.