Like any other lighting technology technical and scientific disciplines, has its proprietary of the term. The term and concept of these special lights and lamps were used to define the characteristics and units of measurement unification. Here are some important terms of lighting.
Light and radiation (Light and radiation)
Just as the human eye can perceive light of electromagnetic radiation, it can be said that the entire spectrum of electromagnetic radiation, a portion of the human eye can see; this part of the wavelength distribution of 360 to 830 nm, only the known spectrum of electromagnetic radiation very small part of the.
Flux (Luminous flux, Φ)
Unit: lumen (lumen, lm)
Light emitted by a human eye and was called all the radiant energy flux.
Light intensity (luminous intensity, I)
Light in a direction of the flux within the solid angle size.
Unit: candela (candela, cd)
In general, the light source to the different intensity in different directions in order to shine their light. Release in a specific direction of radiation known as visible light intensity.
Illumination (Illuminance, E)
Unit: lux (Lux, lx)
Illumination is to be face to face with the ratio of luminous flux. 1 lux of illumination to 1 lumen of luminous flux evenly distributed in the area of one square meter of area.
Brightness (Luminance, L)
Unit: candela per square meter (cd / ©O)
One is face to face or a light source luminance refers to the unit surface in a certain direction of the light intensity density, it can be said that the human eye's perception of the brightness of the light source or face to face.
The metering important formula:
I, light intensity [cd] = solid angle of the flux / solid angle Ω [sr]
E, illuminance [lx] = fall on an area of flux [lm] / This is face to face area [m]
= Light intensity [cd] / (distance [m]) 2
L, luminance [cd / ©O] = intensity [cd] / to be seen in the area face to face [m]
η luminous efficiency [lm / W] = flux generated [lm] / consumption of electric power [W]
Luminous efficiency (Luminous efficacy, η)
Unit: lumens per watt [lm / W]
Light will be consumed on behalf of the efficiency of electrical energy into light
Color Temperature (Co1or Temperature)
Unit: absolute temperature (Kelvin, K)
A light source color temperature is defined as its light color of the same "standard blackbody (black body radiator)" itself is the absolute temperature, this temperature can be in the chromaticity diagram of the Planck to find the corresponding point on the track. The higher the temperature standard blackbody, the radiation out of the blue light spectrum, the more ingredients, the red component also relatively less. To issue for the warm white light color of ordinary incandescent bulbs, for example, the color temperature of 2700K, while the color temperature of daylight color fluorescent lamp is 6000K.
Light color (Light color)
A lamp light color to the color temperature can be simply expressed. Light colors can be divided into three main categories:
Warm: <3300K
Intermediate colors: 3300 to 5000K
Daylight:> 5000K
Even if the same light color, light species may also be issued because of its spectral composition of light are very different color rendering performance differences.
CRI (Color rendering)
Artificial light is generally believed that people should perceive correctly the eye color, just as in the sunlight to see things the same. Of course, this depends on the application of different occasions and purposes of the requirements. According to this standard that is the source of the color rendering properties, known as the "average color rendering index (general color rendering index, (Ra)".
Average color rendering index of the object in a display of color light irradiation with light irradiation in the light of the relative difference between the colors. The value of the assessment method as the reference light, respectively, and light shines on the DIN 6169 test required by the eight color samples and compare them one by one to quantify the differences; the smaller the difference, which represents the measured light of the better color rendering , the average color rendering index Ra of 100 different colors of light can be presented as the color of the light irradiated by light. The lower the Ra value, the color rendering of the more distortion.
Lighting efficiency (Luminaire efficiency)
Lighting efficiency (also known as the lamp light output ratio) is used to assess the energy efficiency of lighting is an important standard, its value is to light the lamp with the luminous flux emitted divided by the luminous flux emitted by the light source itself loaded from the quotient .
Invisible (Invisible Light)
Relative to visible light, wavelength 360 to 830nm electromagnetic radiation outside the visible light is not known. Wavelengths less than 360nm of the electromagnetic wave is the most ordinary people understand the UV, there are other x-ray, r ray, cosmic rays; greater than 780nm, there are infrared electromagnetic radiation and radio waves.
Spectrum (Spectrum)
According to the order of the wavelength of light known as the spectral distribution. Each light source can be formed according to their wavelength in the spectrum graph showing the spectral energy distribution (Power Spectrum Distribution). Sunlight and incandescent bulbs of the spectral energy distribution of a continuous curve, while the discharge lamp is generally non-continuous curve.
Incandescent bulb (Incandescent lamp)
Incandescent light bulbs for the first mature artificial light source, it is the use of filament heating power light-emitting principle. In general, the luminous efficiency of incandescent bulbs, low life expectancy is shorter, but more convenient to use.
Gas discharge lamp (Gas discharge lamp)
Such light-emitting principle of its gas between two electrodes and by electronic excitation light. Can be divided into low-pressure gas discharge lamp, such as fluorescent lamps and high-pressure gas discharge lamp, such as mercury lamps, high pressure sodium vapor lamps and metal halide lamps.
Light-emitting diode (LED)
Light-emitting diodes made of special material for the pn diode. In forward bias, electrons flow in the joints, will be combined to destroy the process of light. Small size, light-emitting efficiency of the original is not high, but in recent years the rapid development of applications has been extended to apply to traffic lights, lights, or even for some special occasions the lighting.
