Lighting terms
Source: Date:2017-03-28

1, light

Light is an electromagnetic wave.

: visible part of the radiation emitted by the light source to the radiation that can produce vision. Is often referred to as the "visible light".

The wavelength of visible light from 380nm----780nm

UV wavelength: from 100nm---380nm, invisible to the naked eye.

Infrared wavelength: from 780nm---1mm, invisible to the naked eye.


2, color temperature

To absolute temperature to K. Is a standard blackbody heating, the temperature rises to a certain extent, the color gradually changes from red - red - Orange - white - Blue - white, blue, the characteristics of the changes of light and color, light color and a blackbody source in a temperature of the same color, we will be at the absolute temperature of blackbody the color temperature of the light source is called.

3, color rendering index (Ra)

Measure source appears to be the true color of the object as the parameter.

Color index (0-100) reconstruction source higher color closer to natural colors.

3.1, color temperature and feel



Atmosphere effect

Light source

Greater than 6500K

Cool (with blue white)

Cool feeling

Fluorescent lamp, mercury lamp


Middle (near natural light)

No obvious psychological effect

Fluorescent lamp, metal halide lamp

Less than 3300K

Warm (with orange yellow white)

Warm feeling

Incandescent lamp, halogen lamp cup

3.2, the human body clock and color temperature


3.3, the effect and purpose of color

Light flux (LM Lm)

Said how much the luminous flux, luminous unit is. (the greater the number of light bulbs)






A highly desirable place for color identification, such as printing, printing and dyeing, etc.


very good

Display and display of color television



Indoor lighting



Outdoor lighting



The color requirements are not high places, such as parking, freight yard, etc.

5, light effect

The luminous flux source and power consumption ratio. Unit: lumen / watt (Lm/W)

6, average life

Also rated life, it refers to a group of lights up to half the number of hours of light damage.

7, light intensity

Unit solid angle of the flux unit: CD

8, illumination

Illumination is used to illustrate the illuminated area (face) is irradiated on the degree, usually expressed in the luminous flux per unit area received by units for Lux (LX) or lumens per square meter (lm/m2).

9, brightness

Brightness is used to represent the object surface emitting (or reflective) physical strength, the ratio of projection area in the direction perpendicular to the light emitting intensity and luminous surface in the vision object of gaze direction on the surface, the surface brightness of light emitting units per square meter, Candela (cd/m2).

10, luminous efficiency

Commonly referred to as light effect, optical source is described and the quality of the economy, it reflects light at the same time consumption per unit energy radiates much light flux, the unit is lumens per watt (lm/w)

11, beam angle

Refers to the angle of the light bulb lighting angle. Generally have 10 degrees, 24 degrees, 38 degrees of 3 kinds.

Below is 3 exactly the same power just 3 different irradiation beam angle lamp on the wall effect diagram and 3 beam light distribution curve. The same power lamp beam angle increases the center light intensity is small, the spot was wider and soft, reflective phase beam angle is smaller and the intensity is big, the more narrow the hard spot.

Effect of different beam angles

12, the appearance of color and illumination

The color index light source and illumination together determine visual clarity environment. There is a balance between illuminance and color rendering index. The results obtained from extensive experiments is: with the display lamp lighting office color index Ra>90, on the satisfaction of their appearance, rather than by the color index of low light (Ra<60) lighting office, illuminance value higher than 25%.

To note is the visual appearance for good, if in order to save energy and reduce indoor illumination to visual function deterioration level, is not feasible. Should choose the best color rendering index and high luminous efficiency of the light source with appropriate illumination, in order to obtain a good visual effect with the minimum energy costs.  


Color class

General color index range

Examples of application



Ra = 90

Color matching, color inspection, etc.


90>Ra = 80

Printing, food inspection, paint, shops, restaurants, etc.


80>Ra = 60

Mechanical and electrical assembly, surface treatment, control room, office, department stores, etc.


60>Ra = 40

Machining, heat treatment, casting, etc.


40>Ra = 20

Warehouse, heavy metal warehouse


13, color temperature and illumination level

14, light environment

Light environment is the people of light in certain visual space perception psychology.

A good light environment to create a good visual experience, such a good visual experience directly affect people's physical and mental health.

People to create a good light environment at the same time, to consider the problem of energy saving. The concept of green lighting is how to reduce the release of mercury, how to save the limited energy.

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