Стр. 551 - OSRAM_lamp_2014

11.03
Color temperature
Unit of measurement: Kelvin [K]
The color temperature of a light source is defined in
comparison with a “black body radiator” and plotted
on what is known as the “Planckian curve”. The higher
the temperature of this “black body radiator” the greater
the blue component in the spectrum and the smaller
the red component. An incandescent lamp with a warm
white light, for example, has a color temperature of
2700 K, whereas a daylight fluorescent lamp has a color
temperature of 6000 K.
Light color
The light color of a lamp can be neatly defined in terms of
color temperature. There are three main categories here:
Warm White <3300 K
Cool White 3300 – 5300 K
Daylight > 5300 K
Despite having the same light color, lamps may have very
different color rendering properties owing to the spectral
composition of their light.
Color rendering
As a rule, artificial light should enable the human eye to
perceive colors correctly, as it would in natural daylight.
Obviously, this depends to some extent on the location
and purpose for which light is required.
The criterion here is the color rendering property of a light
source. This is expressed as a “general color rendering
index” (Ra).
The color rendering index is a measure of the
correspondence between the color of an object (its
“self-luminous color”) and its appearance under a
reference light source. To determine the Ra values, eight
test colours defined in accordance with DIN 6169 are
illuminated with the reference light source and the light
source under test. The smaller the discrepancy, the better
the color rendering property of the lamp being tested.
A light source with an Ra value of 100 displays all
colors exactly as they appear under the reference light
source. The lower the Ra value, the worse the colors are
rendered.
Luminaire efficiency
Luminaire efficiency (also known as light output ratio) is
an important criterion in gauging the energy efficiency of
a luminaire. This is the ratio between the luminous flux
emitted by the luminaire and the luminous flux of the lamp
(or lamps) installed in the luminaire.
Average life
The average life of a lamp is an average of the lives of
individual lamps operated under standard conditions
(50% failure = average rated life).
Service life
Service life is a simple practical measure of the
economical life of a lamp. It is the number of hours of
operation after which the system luminous flux (i.e. the
product of the relative luminous flux and the relative
proportion of lamps still in operation) is around 80% of the
initial value.
Chromaticity diagram to DIN 5033
y
HMI®
HQI®/D ≥ 400 W
LUMILUX® Daylight 865
HQI®/D
HQI®/N
HQI®/HCI®/NDL
LUMILUX®
Cool White
HQI®/HCI®/WDL
Halogen
Low-voltage halogen lamp
LUMILUX®
Warm White 830
SKY
WHITE
Extract from the chromaticity diagram showing the Planckian curve
x
400 450 500 550 600 650 700 750
Wavelength λ
Spectrum of a BIOLUX® fluorescent lamp.
The radiation is very evenly distributed over the entire
visible range.