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LED Information
What is LED?
LED is abbreviation of light-emitting diode. It is a
solid-state semiconductor device that converts
electrical energy directly into light. On its most
basic level, the semiconductor is comprised of two
regions. The p-region contains positive electrical
charges while the n-region contains negative
electrical charges. When voltage is applied and
current begins to flow, the electrons move across
the n region into the p region. The process of an
electron moving through the p-n junction releases
energy. The dispersion of this energy produces
photons with visible wavelengths. This effect is
called electroluminescence.
LEDs are used as indicator lamps in many devices,
and are increasingly used for lighting. Introduced
as a practical electronic component in 1962, early
LEDs emitted low-intensity red light, but modern
versions are available across the visible,
ultraviolet and infrared wavelengths, with very high
brightness.
Terminology
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Lumen(Im)
¡V The international (SI) unit of luminous
flux or quantity of light and equals the
amount of light that is spread over a square
foot of surface by one candle power when all
parts of the surface are exactly one foot
from the light source. For example, a dinner
candle provides about 12 lumens. A 60-Watt
soft white incandescent lamp provides 720
lumens. |
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Watt(W)
¡V The unit of electrical power as used by an
electrical device during its operation. Many
lamps come with rating in watts to indicate
their power consumption. A light source with
a higher lumen per watt value is more
efficient. |
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Efficacy (lumen/watt) ¡V The luminous
efficiency of a light source to convert
electricity energy to light energy which is
expressed in lumen output per unit power
input. |
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Colour
Rendering Index (CRI) ¡V The calculated
rendered colour of an object. The higher the
CRI (based upon a 0-100 scale), the more
natural the colours appear. Natural outdoor
light has a CRI of 100. Common lighting
sources have a large range of CRI. |
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Color Temperature (K) ¡V A black-body
radiator will have a different colour when
it is heated up to different temperatures.
The temperature at which the heated
black-body radiator matches the colour of
the light source is the colour temperature
of the light source, usually specified in
Kelvin (K). |
Comparison of Conventional Light Sources
|
Light Sources |
Advantages |
Disadvantages |
|
High Pressure
Sodium Lamp |
efficient |
Transient,
extremely inefficient, light loss |
|
Incandescent
Lamp |
Good colour
rendering, very cheap |
Transient,
extremely inefficient, light loss |
|
Tubular
Fluorescent Lamp |
Cheap,
efficient |
Emit
electromagnetic radiation, emit flickering
light, contain toxic heavy metals, incapable
of working in cold environment, long warm up
time, incapable of dimming, light loss |
|
Compact
Fluorescent Lamp |
efficient |
Emit
electromagnetic radiation, contains toxic
heavy metals, incapable of working in cold
environment, light loss, long warm up time,
relatively expensive |
|
Halogen Lamp |
Good colour
rendering, narrow spot light |
Transient,
extremely inefficient |
|
Each kind of
lamps has its disadvantages respectively,
hence the need for the variety of lamps. |
Analysis of LED
|
Advantages |
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Super lifespan
¡÷
Last at least 50 times longer than
incandescent bulb, there is no need to
replace the light source, reducing or even
eliminating ongoing maintenance costs and
periodic re-lamping expenses |
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Extremely low running cost
¡÷
Available up to 208 lm/W, up to 90% of
electricity saving over against incandescent
bulb |
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Inherently rugged
¡÷
No filament of fragile glass to break,
vibration and impact proof |
|
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Cold light source
¡÷
No electromagnetic radiations emitting, do
not heat up the surroundings |
|
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High-quality light
¡÷
No compromise between efficacy and CRI |
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Directional
¡÷
No wasted light, any pattern possible |
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Environmental friendly
¡÷
Contain no mercury, lead or other heavy
metals |
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Instant on
¡÷
No flickering or warm up period as reaching
full brightness in nanoseconds |
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Increased safety
¡÷
Require low voltage (12-24VDC) power supply |
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Ideal for low temperatures
¡÷
No issues starting in cold environment |
The only disadvantage of LED is the
relatively high initial cost. However, the price
difference can be offset by extremely low running
cost. Moreover, huge amount can be saved on the
total cost of ownership (TCO).
Electricity Charge Comparison
|
Light Sources |
Wattage |
Quantity |
Total Wattage |
Minutely
Charge |
Hourly Charge |
Daily Charge |
Monthly
Charge |
Yearly Charge |
|
50-watt
Halogen |
50 |
200 |
10,000 |
HK$0.2012 |
HK$12.07 |
HK$289.68 |
HK$8,690.40 |
HK$105,733.20 |
|
Corresponding
LED lamp |
6 |
200 |
1,200 |
HK$0.0241 |
HK$1.45 |
HK$34.76 |
HK$1,042.85 |
HK$12,687.98 |
|
T5 Tubular
Fluorescent |
28 |
200 |
5,600 |
HK$0.1127 |
HK$6.76 |
HK$162.22 |
HK$4,866.62 |
HK$59,210.59 |
|
Corresponding
LED tubular |
15 |
200 |
3,000 |
HK$0.0604 |
HK$3.62 |
HK$86.90 |
HK$4,866.62 |
HK$31,719.96 |
|
35-Watt
Halogen |
35 |
200 |
7,000 |
HK$0.1408 |
HK$8.45 |
HK$202.78 |
HK$2,607.12 |
HK$74,013.24 |
|
Corresponding
LED lamp |
3 |
200 |
600 |
HK$0.0121 |
HK$0.72 |
HK$17.38 |
HK$6,083.28 |
HK$6,343.99 |
|
Compact
Fluorescent |
26 |
200 |
5,200 |
HK$0.1046 |
HK$5.28 |
HK$150.63 |
HK$521.42 |
HK$54,981.26 |
|
Corresponding
LED lamp |
12 |
200 |
2,400 |
HK$0.0483 |
HK$2.90 |
HK$69.52 |
HK$4,519.01 |
HK$25,375.97 |
|
Metal Halide |
50 |
200 |
10,000 |
HK$0.2012 |
HK$12.07 |
HK$289.68 |
HK$8690.4 |
HK$105,733.20 |
|
Corresponding
LED lamp |
24 |
200 |
4,800 |
HK$0.0966 |
HK$5.79 |
HK$139.05 |
HK$4,171.39 |
HK$50,751.94 |
|
Remark: the above calculation
is based on the electricity tariff of
HK$1.207/unit, ¡§Unit¡¨ means one
Kilowatt-hour (kWh) of electricity. |
Specification Comparison
|
Light Sources |
Efficacy (lm/W) |
Life (hours) |
CRI (Ra) |
Colour Temperature (K) |
|
INCANDESCENT |
12 |
1,000 |
100 |
2,000/3,000 |
|
HALOGEN ¡V
line voltage |
17 |
2,000 |
100 |
3,000 |
|
HALOGEN- low
voltage |
21 |
2,000 |
100 |
3,000 |
|
COMPACT
FLUORESCENT ¡V integrated electronics |
69 |
6,000 |
80-89 |
2,700-6,500 |
|
COMPACT
FLUORESCENT ¡V external electronics |
78 |
6,000 |
80-89 |
2,700-6,500 |
|
TUBULAR
FLUORESCENT ¡V standard light |
62 |
10,000 |
60-69 |
2,900-6,500 |
|
TUBULAR
FLUORESCENT ¡V extra light |
77 |
10,000 |
80-89 |
2,700-6,500 |
|
TUBULAR
FLUORESCENT ¡V high efficacy |
94 |
10,000 |
80-89 |
2,700-6,500 |
|
HIGH PRESSURE
SODIUM ¡V standard light |
102 |
12,000/25,000 |
80 |
2,200 |
|
HIGH PRESSURE
SODIUM ¡V comfort light |
72 |
12,000/25,000 |
70 |
2,200 |
|
HIGH PRESSURE
SODIUM ¡V white light |
30 |
12,000/25,000 |
50 |
2,900 |
|
MEATAL HALIDE |
72-108 |
6,000/8,000 |
65-90 |
3,000-5,600 |
|
MERCURY VAPOR |
36-60 |
5,000/10,000 |
50-60 |
3,500-4,200 |
|
Luminux ® LED |
74-132 |
100,000 |
80-92 |
2,600-10,000 |
Why
Luminux® LED Lamps
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Luminux®
LED Lamps |
Other LED
Lamps |
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Built-in constant-current
¡¥Power Factory¡¦ ¡V regulate the drive current
in order to optimize the lumen maintenance
and maximize the lifespan |
Rely on
external adapter to feature constant-current
or even worse adapter which is featureless |
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Dedicated constant-voltage
LED driver ¡V regulate the voltage of
direct-current power in order to
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External
adapter ¡V supply direct-current power of
variable voltage to cause fluctuation on the
colour |
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preserve the colour
temperature of light and the working
temperature of LED chips, facilitate the
dimming of LED lamps and simplify the
multi-lamp installation by connecting in
parallel mode |
temperature
of light and the working temperature of LED
chips, fail in dimming and connecting in
parallel mode |
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Built-in Working Temperature
Control System ¡V reduce the drive current
automatically once the working temperature
have reached the abnormal level in order to
avoid overheating which can shorten the
lifespan |
No protection
at all ¡V burn out easily due to the frequent
overheating |
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Aluminium-core printed
circuit board ¡V conduct the heat from the
LED chips to the heat sink most efficiently
|
Ordinary
fiber-core printed circuit board ¡V conduct
the heat inefficiently heat dissipation to
the high power LED |
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Dynamic Airflow Heat Sink
Design ¡V dissipate the heat most efficiently
in order to minimize the lumen depreciation
of LED chips |
Typical heat
sink design ¡V the luminosity of lamps drop
rapidly due to the inefficient heat
dissipation to the high power LED |
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CREE LED chips ¡V adopt LED
chips from the US-based and industry-leading
manufacturer in order to ensure the optimum
efficacy, luminosity and reliability |
China-made
and Taiwan-made LED chips ¡V inefficient, dim
light emitting and unreliable |
|
Italy-made core ¡V solder the
LED chips and electronics by automated
machinery in order to secure the best
quality of fabrication |
China-made
core ¡V colder the LED chips and electronics
manually with poor quality of fabrication |
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One year warranty ¡V give
customers the assurances on the reliability
of lamps |
No warranty ¡V
customers get no assurance to the lamps |
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Unique 9X3watt extra-high
power LED lamps ¡V require the most
sophisticated technology among the
production-ready LED lamps |
3X3-watt is
the highest power of production-ready LED
lamps which require low technology only |
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Dimming available ¡V
convenience and increased design flexibility |
Incapable of
dimming |
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Various beam angles available
(15¢X-
80¢X)
¡V suitable for most environment |
Fixed beam
angle ¡V limited application |
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High CRI of 80 ¡V render the
colours of various objects faithfully |
CRI below 70
¡V render the colours of various objects
inaccurately |
Strength of Cree LED chips
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Steady and
enduring luminous flux output, greater than
70% of initial intensity after 50,000hours
of operation |
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Supreme
efficacy of 208 lm/W, Record high of the
industry |
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Industry-highest CRI of 92 |
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Maximum
electric current of 1,000 mA |
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High Tolerance to junction
temperature, up to 150¢XC |
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High
tolerance to humidity, up to 85% |
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Broad colour
temperature spectrum, 2,600K-10,000k
available |
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RoHS-compliant |
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Covered by a
glass lens for optimum light transmission |
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