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3M Announces Glare-Free Lighting Technology for Industryial Applications

23 February 1998

3M Offers Glare-Free Lighting Technology that Simulates Sunlight and Provides Efficiency, Safety, and Long Life

    ST. PAUL, Minn., Feb. 23 -- Proving that 3M is a reliable
source of "bright ideas," the company is beginning to market an innovative
light source called 3M(TM) Light Pipe(TM) that offers a unique set of benefits
for factory and office applications.
    According to Paul Clark, national account manager for 3M's Specified
Construction Products Dept., in St. Paul, "conventional light sources have
traditionally had a variety of shortcomings, which include heat, ultraviolet
radiation, safety concern and loss of output over time.  These drawbacks are
eliminated with Light Pipe, which works on a different operating principle,"
Clark said.
    3M Light Pipes deliver light from a remote light source through clear,
air-filled plastic tubes up to 66 feet (20 m) long and 10 inches (25 cm) in
diameter.  The safe and light-weight tubes operate at room temperature and
emit natural-looking light that studies say can actually contribute to a sense
of well-being among the people using it.
    3M Light Pipes have been installed in several facilities in Europe and
the United States to date.  For example, Light Pipes are being used in the
paint inspection area of Chrysler Corp.'s Warren Truck Assembly Plant.  In
addition, the technology will be included in the new Automotive Industry
Center 3M plans to open in metropolitan Detroit this fall.
    Two technologies combine to make the 3M Light Pipe work.  One is a
microwave-powered sulfur lamp that produces balanced visible light with almost
no heat-generating infrared or fabric-fading ultraviolet rays.  The other is
an optical lighting film developed over the past 10 years by 3M researchers
that uses microprisms to direct light within the system's distribution tube.
    The system gets its light from a full-spectrum sulfur lamp developed by
Fusion Lighting, Inc., a Rockville, Md.-based company in which 3M holds
equity.  Called Light Drive(TM) 1000, the luminaire contains a small amount of
sulfur and inert argon gas in a quartz bulb about the size of a lollipop.
Showering the sulfur with microwaves ionizes it, producing 135,000 lumens of
flicker-free light that is very similar to sunlight.  A high efficiency
reflector directs the lamp's output into the Light Pipe.
    Light from the luminaire is contained within the Light Pipe by a lining
of 3M(TM) Optical Lighting Film (OLF) and a reflective cap at the opposite
end.  The pipe is constructed of OLF rolled into a tube and surrounded by a
clear polycarbonate casing that wards off dust and moisture.  The inward-
facing side of the film is flat while the outward-facing side contains rows of
very precise prisms measuring just 0.007 inches (0.18 millimeters) tall.  OLF
is made using 3M's proprietary microreplication process that duplicates tiny
structures such as pyramids or grooves with extremely high precision.
    OLF acts as a mirror to light that strikes it at an angle of less than 28
degrees, reflecting more than 98 percent of it back into the tube.  When light
strikes the film at steeper angles, however, it passes through with virtually
no loss.  Light is extracted from the tube by a white diffuser strip affixed
longitudinally along the inner wall of the tube.  It interrupts the wall-to-
wall reflections inside the tube, scattering light that strikes it at angles
great enough to pass through the tube's wall.
    3M has been able to create several important benefits by combining the
lamp and light film technologies.  Glare and reflections are eliminated
because the light source is tucked out of sight at one end of the pipe.
Safety is enhanced as well, since the Light Pipe contains no gas, glass or
electricity.  Any heat generated by the system is confined to the light source
itself, so the tube operates at room temperature.  That means the system can
help reduce air conditioning costs and is a good choice for lighting large
coolers or refrigerators.
    The Light Pipe system is marketed in 6-foot lengths and is recommended
for installations of at least 19 feet (6 m).  Cost is higher than conventional
lighting, with a 20 meter pipe costing about $6,000.  But the 3M system also
reduces electricity and maintenance costs by as much as 40 percent.
"Generally, you get more light for your money, and the units eventually pay
for themselves," Clark says.  He adds that 3M experts can help customers
calculate the exact costs and savings of a 3M Light Pipe system.

SOURCE  3M Automotive