Karpen conceptualized his invention in what seemed like
a flash of lightening. He realized that neodymium oxide
light bulbs — the type that transmits this white
light — provides better lighting and replaced all
the bulbs in his house with these in 1988. Upon driving
upstate in an old Dodge Dart in the summer of 1989, it
occurred to him that they would also be helpful on the
The growing controversy over headlight
glare has presented an opportunity
Corp. The Southfield-based
auto supplier hopes a New York inventor's anti-glare
technology will give it a wedge in the competitive business
of headlight replacement. Later this month, Federal-Mogul
will begin selling glare-resistant "TruView" headlamps
under the company's Wagner Lighting name. The lights
use a rare earth compound called neodymium oxide to filter
out glare producing yellow light. As a result, Tru-View
headlights cast a pure-white beam more akin to daylight
than the more common yellowish halogen lights.
In "The Road Less Traveled", which appeared
in the July 1998 issue of LD+A, I described
a novel solution
to the problem of headlight glare: To add neodymium oxide,
a rare earth compound, to the glass of the bulb to filter
a portion of the yellow wavelengths between
565 and 595 nm.
The News says Federal-Mogul plans to sell TruView lights
for $14.99 per lamp, or
about 50% more than base halogen replacement bulbs. That
price is far lower than
optional high-intensity discharge headlamp systems that sell
for up to $1,600 in some premium vehicles. Though popular
in Europe—HID lamps have been blamed for excessive
glare and currently are under study by the U.S. National
Highway Traffic Safety Administration.
It has long been recognized that visual
discomfort from the glare from motor vehicle headlights has
been a vexing
problem that has remained unsolved until the present time.
This article presents a novel solution to the problem of
glare which will eliminate much of the disability and discomfort.
In addition, it will provide
better illumination for the driver.
- Future brighter for Federal-Mogul
...Federal-Mogul is marketing headlamps
made with neodymium-doped glass. "It filters out more
of the yellow light and essentially allows your eyes to pick
up more of the blues and the reds," Federal-Mogul's
Keith Bucher says of the glass, which is infused with neodymium
oxide. The resulting effect reduces glare from another vehicles'
headlamps, and your ensuing eye strain.
Daniel's investigations have shown that glare is reduced
when viewed through glass containing a light dose of the
rare earth element neodymium. As little as 3 percent by weight
is enough, adding perhaps $5 to the cost of windshield glass
for an average car.
The Wagner Lighting Division of Federal Mogul Corp. has
been producing neodymium-oxide-dosed headlights. Schott Glass
Technology has plans for manufacturing mirror glass containing
neodymium oxide. (It's claimed this would obsolete the two-plane
flip-up mirrors now in use.) And Karpen's latest patents
incorporate the compound into automotive windshields.
SAE Technical Papers
- 2005-01-0440 - Recent Research on Neodymium Glass as
applied to Headlights, Rear View Mirrors, and Windshields
Neodymium Oxide, as a component of glass, selectively filters
out a portion of the yellow light. Neodymium Oxide can be
incorporated into the glass of a headlight lamp, the rear
view mirror, and the windshield of a motor vehicle. A series
of tests was conducted with 30 subjects recruited to quantify
the reduction in glare and improvement in vision buy the
use of Neodymium Oxide doped glass for these applications.
Subjects were put through a series of tests in an optometric
examination room setting. The group was then divided in half,
and one half received new standard headlights, and the other
have received Neodymium headlights in a road test.
Windshields have remained unchanged
for the past several decades. Meanwhile, the problem of headlight
glare is getting
worse with the advent of the brighter headlights. A novel
approach is presented in this paper by doping the windshield
glass with Neodymium Oxide, a rare earth compound, to filter
out the excess yellow light. Research results indicate that
0.042 lbs/sq ft (0.362 Kgs/sq meter) maximizes glare reduction
while minimizing the amount of Neodymium Oxide necessary.
- 2001-01-0319 - Neodymium Oxide-Doped Headlight Lamps
Headlight glare us a continuing problem
that has resisted efforts to solve it until now. A novel
approach is provided
in this paper by doping the glass with Neodymium Oxide, a
rare earth compound, to filter out the excess yellow light.
Neodymium Oxide dopes lighting improves black and white
contrast, so one can see road markings easier. The primary
colors red, green and blue are enhanced with increased saturation,
making them easier to see at low levels of illumination.
Preliminary results indicate that "spots in your eyes" are
reduced in intensity and in duration in the visual field.
Apparently glare is reduced by a factor of 6 or 7 compared
with standard lamps.
Transportation Research Board Technical
This report documents the work done
in a Safety IDEA research project on the visual effectiveness
of Neodymium Oxide doped headlights, rear view mirrors, and
windshields in reducing glare and improving vision. This
research project had two stages: clinical optometric experimentation
under controlled conditions, and a subjective road test.
Truck divers with commercial driver's licenses were recruited
by advertising in local newspapers on Long Island. The subjects
were all given a standard optometric examination. Of the
30 subjects, who were paid for their participation in the
study, 29 needed a new optometric prescription. Another 14
had significant eye pathologies. Subjects were both male
and female and ranged in age from 29 to 75, with just 2 subjects
under 40 years in age.
After completion of the standard optometric examination,
subjects were run through a series of 9 tests involving
vision tasks that might be expected of a motorist. These
tests involved the ability to identify lettering through
various types of windshield and mirror glass, the ability
to discertain colored signs at low light levels, and the
ability to see yellow turn signals. Other tests compared
stereoscopic depth perception, and the length of time after
images remain after exposure to glare. [Read
the Full Report]