Silicones simplify the production of energy-saving, climate-protecting light-emitting diodes.
LED displays have a long lifetime, operate extremely efficiently and permit genuinely novel lighting effects. High-performance optical silicones from WACKER allow LEDs to be produced inexpensively and in large quantities.
Light is a symbol of progress. The incandescent light bulb,
once the pioneer of a global lighting revolution, is disappearing from store
shelves. In tomorrow’s multimedia society, color displays the size of a house
will generate crystal-clear images, and entire sports stadiums will be lit by
Light can also be used as a tool. For example, laser scalpels have become an
indispensable part of medical technology.
These new lighting technologies are driven by energy-efficient light-emitting
diodes (LEDs). WACKER’s researchers have developed an innovative UV-curing
silicone that makes it relatively inexpensive to manufacture the energy-saving
light sources of the future.
The Future of Light
Nothing travels faster than light. Both the Internet and
telephones rely on light waves. Fiber-optic cables transmit light pulses around
the globe at incredible speeds. The last 10 years, however, have seen both a
proliferation of data transfer and new visualization possibilities - cell
phones can provide information and books can be read on electronic readers.
These technologies are exceptionally efficient thanks to energy-saving LED
backlighting. “High energy efficiency, a great color range, stability, long
life, brilliance and new design options make light-emitting diodes appealing
for all lighting applications,” says Dr. Klaus Angermaier, senior marketing
manager, Transportation and Energy, at WACKER. LEDs, he says, are shedding a
whole new light on the market.
WACKER's new optical high-performance silicone brand LUMISIL enables optical lenses for LEDs to be produced directly on the light-emitting diode chip. The more-efficient process cuts the traditionally high cost of LED production.
Out with the Old, In with the New
The incandescent lamp has run its course. On Sept. 1, 2009,
100-watt incandescent bulbs were banned from sale in the European Union; lower
wattages must be phased out by 2012. According to the Photonik 2020 initiative,
about 8 billion incandescent bulbs will eventually need to be replaced
Various lamp types can be used as replacements, including improved incandescent
and halogen lamps, and energy-saving compact fluorescent (CFL) lamps. LED
technology is particularly attractive because of its high light yield, which is
doubling roughly every three years. A conventional LED can currently provide
about 50 lumens per watt; this will likely be increased fourfold soon.
In contrast, an incandescent bulb provides 12 lumens per watt. However, despite
being so inefficient, it is still the preferred light source in many
households. Incandescent bulbs produce so much heat that fingers can be burned
by touching them; only 5% of the energy they consume is actually converted into
Switching to more efficient light sources can provide cost and energy savings.
Experts estimate that private households in Germany could save up to €2 billion per year.
“The EU expects that, in Germany
alone, replacing incandescent with energy-saving lamps will save 7.5 billion
kilowatt hours in private households. Replacing these with LEDs will save even
more,” says Prof. Norbert Huttenhölscher, director of EnergieAgentur NRW.
“The energy savings for televisions with LED lighting can be as much as 50%,”
says Bernd Franke, head of strategy and information at the VDE Institute.
“Compared to fluorescent tubes, LEDs save up to 60% energy - and for much
LEDs will take over our roads as well, where updates are needed. “According to
estimates by the German Electrical Luminaires and Electrical Lamps Trade
Associations,1 for example, 50% of German cities still use street lighting
based on 1960s technology,” Hüttenhölscher says.
Climate Protection Technologies, an initiative by the German Federal
Environment Ministry, subsidizes the modernization of municipal street
lighting. Only 3% of these “vintage” lights are replaced yearly. Nationwide
savings are estimated at 2.7 billion kilowatt hours, or €400 million.
The new material blend bonds well and does not cloud the lens, Hüttenhölscher
says. Prof. Tran Quoc Khanh of the Lighting Department at Darmstadt Technical
University agrees. “The
street lamp of the future is the LED lamp. The potential for savings is huge,”
As LED performance increases, the materials used (such as the lenses) must meet
new challenges. Materials previously and currently being used can yellow under
intense light fluxes. In the future, silicone will be preferred for modern
high-performance LEDs. “Silicone elastomers have the necessary heat and light
stability,” says Philipp Müller, Ph.D., an applications engineer at WACKER in
With a new optical high-performance silicone, marketed under the trade name
, optical lenses for LEDs are produced directly
on the light-emitting diode chip. This efficient method reduces the
traditionally high production costs.
“Until now, LED manufacturers had been using a complex injection-molding
process to make the silicone lenses. With our product, they can eliminate about
five process steps,” Müller says.
The novel silicone is applied by conventional dosing to produce the optical
element, which is then flash-cured by exposure to UV light. WACKER’s chemists
came up with a material blend that was suitable for this step and also provided
optimum adhesion. “The silicone has to bond equally well to both metal and
plastic and must not cloud the LED lens,” Müller says.
LEDs Make Driving Safer and Help Reduce Fuel Consumption
The new LED material has found many uses. “One of the
world’s leading LED manufacturers endorses LUMISIL, with its outstanding
transparency, excellent mechanical strength and long-term resistance to extreme
UV exposure,” Müller says. The bright LEDs work well as spots and
light-emitting surfaces: energy-saving lamps have lifetimes of about
6,000-15,000 hours; LEDs offer as many as 50,000 hours. Analysts from iSuppli
predict that by 2025 one in every three light sources will be an LED.
The diodes also protect the climate. Professor Khanh of the Laboratory of
Lighting Technology at Darmstadt Technical University
says that, with today’s technology alone, Germany could cut its carbon
emissions by 1.6 million metric tons per year. This translates to annual
savings of €400 million. In
global terms, current LEDs could cut the world’s energy demand by around 30%
(almost a fifth is still consumed for lighting). Technical advances could slash
that by a further 30%, industry experts say, which would save up to 650 million
metric tons of CO2
LEDs are commonly used in automotive applications, offering benefits that
include energy and cost savings. The diodes’ low power consumption significantly
reduces fuel consumption; in Germany
alone, this can save several million liters of fuel per year. The Audi R8 uses
LEDs in its main and dipped headlights, position lights, and turn signals.
LED lights offer benefits to drivers as well. At night, the road and curb
appear in natural colors, allowing the human eye to better distinguish the
contrasts. LED systems also enable intelligent lighting control, in which the
intensity is adjusted according to weather and traffic conditions.
The new range of lighting technology that LEDs provide allows novel lighting
and illumination solutions to be possible. LEDs allow more flexible control of
color shades, giving lighting designers a new range of creative possibilities.
It is only a matter of time until LEDs become an established part of everyday
life. Silicones from WACKER will play an important role in this. “With them, we
can also serve major markets like the United
States and Japan,” says Dr. Bernd Pachaly,
head of the Elastomers Business Unit at WACKER. “We are expecting annual growth
rates of 20% in LEDs.”
About the CompanyWACKER is a global chemical company with some
15,900 employees and annual sales of around €4.3 billion (2008). WACKER has 27 production sites and over 100
sales offices worldwide.
For more information, visit www.wacker.com.
1. The German trade associations Electrical Luminaires and Electrical
Lamps were replaced by the joint trade association Light in September 2009. For
details, visit www.zvei.org.