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Color temperature |
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When the color shoots form the light source is the same with the color eradiate form the black body, then we call the temperature of that black body be the color temperature of the black body, express by absolute temperature K £¨Kelvim£©
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Correlative color temperature |
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When the color shoots from the light source is close to the color form the black body, the temperature of which be called as color temperature, express by K.
The gaseous discharge lamp-house always is the discontinuous spectrum, which could not identical with the black body¡¯s continuous spectrum, so we describe its color feature in correlative color temperature. The color temperature (or correlative color temperature), which under 3300K, the color would be reddish, and it, would let people fell warm, but when the color temperature over 5300K, the color then you¡¯ll fell cold. So people like to choose lamp-house which color temperature over 4000K in tropic region, but choose the under 4000K one in the cold area. |
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Color rendering index |
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Sunshine and incandescent lamp all radiate continuous spectrum, during the visible light¡¯s wavelength; include red, orange, yellow, green, blue and purple light. The color would be distortion to some extent as the object under the irradiation of sunshine and incandescent lamp, the present degree of that real color called color rendering index.
In order to take measurable judge to the color rendering index, we import the concept of color rendering index, based on standard lamp-house, and set the index be 100, then the rent will below 100. The color rendering index express as Ra, the color rendering property is better when the number of Ra get big. |
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Luminous flux unit: lumen (lm) |
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The photons summation shoots form lamp-house in a minute, called Luminous flux.E.g.: the luminous flux of a 40W incandescent lamp is about 350-470lm, but the luminous flux of a 40W fluorescent lamp is about 2800lm, that is 6-8 times than the incandescent lamp. |
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Light intensity unit: Candela (cd) |
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The luminous flux of the lamp-house shoot forms a given solid angle, called luminous intensity, shortened form light intensity.
1cd=1lm¡Ásr
i.e, when you shoot a light of one lm from a unit, when light intensity is one Candela, sr is a sphere, which is the unit of solid angle. The max of the solid angle is 4¦Ð steradian.
e.g.: the luminous flux of a 40 incandescent lamp is 350lm, i.e, the average luminous intensity: 350lm/4¦Ðsr=28cd
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Illumination unit: lux (lx) |
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Illumination is the luminous flux when the lamp-house shoots at a unit area.
1Lx=1Lm¡Ám-2
i.e, the illumination is 1 lx when 1 lm luminous flux even distribution on 1 sq.m area. When you read under the 40W incandescent lamp, the illumination of the desktop is 200-300lx. |
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Brightness unit: Candela per square meter£¨cd/m2£© |
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The brightness at a direction is the ratio of projection surface area between light intensity and luminous surface in the same side.
Solar brightness: 2¡Á109cd/m 2
Brightness of incandescent lamp is about: (3-5)¡Á106cd/m 2
Brightness of limber fluorescent lamp just: (6-8)¡Á103cd/m 2 |
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Optical unit: lumen/watt £¨lm/w£© |
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The ratio of total luminous flux and the wasting of the electric power, which are from the same lamp-house, called the optical of this lamp-house.
Average lifeunit: hour (H)
It means to turn on a set of lamps, the hours of the 50% still bright. |
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