Competition for A Modern Lamp
"When you come out with a product, you need to give people choices."
(Gilbert Reiling, former GE engineer, 1996)
If a product is successful, other companies inevitably will try to supply that product.
Sometimes competitors come up with a different way of doing the same thing or at least
make significant improvements. Sometimes they sign a licensing agreement.
In the wake of the energy crisis of the 1970s, public demand for an energy-efficient light bulb
resulted in several new products. Several of these designs either stayed in the
enjoyed only modest success in the marketplace. Compact fluorescent lamps (CFLs)
caught on, though. Twenty years of competition has led to refinements in the basic
technology and a large variety of styles. Below, we will examine some of the early
competitors to the CFL and a few of the variations on the theme.
Improved Incandescent Lamps
An early response to the problem of making a better light bulb was to keep as much of
the incandescent technology as possible and to introduce specific refinements. This not
only allowed researchers to draw on decades of existing knowledge to guide their work,
but also meant that new designs could use existing production equipment.
One design, already on the market in small numbers, simply replaced the argon gas in
a light bulb with krypton gas. Krypton does not conduct heat as well as argon and slows
tungsten evaporation from the filament; both factors boost lamp efficacy. An advance in
gas production technology lowered the price of krypton in the 1960s, leading to special
designs like the "Superbulb" from Westinghouse.
Tungsten halogen lamps had been developed in the 1950s, and several designs
intended to replace regular filament lamps went onto the shelf in the 1960s. Some of
these designs came off of the shelf and are available today, though they are more
expensive than regular lamps.
"Heat mirror" lamps
Another way to boost efficiency was to recycle some of the heat produced by a lamp.
Dichroic coatings, developed in the early 1960s, allowed some wavelengths of light to
pass, while reflecting other wavelengths. Duro-Test Corporation introduced a spherical
lamp with an dichroic coating on the inside in 1980. This "heat-mirror" technique
allowed visible light to pass but reflected infrared heat back onto the filament, raising
the filament's temperature.
Higher filament temperatures meant better efficiency, but the lamp proved fragile and
somewhat difficult to make. Duro-Test withdrew the "MiT-Wattsaver" lamp in 1988, but
GE then adapted the technology by coating their tungsten halogen lamps with
The resulting "Halogen-IR" lamps, though expensive, exceeded 30 lumens per watt.
Small Metal Halide Lamps
Since the early 1960s, metal halide lamps have contributed to more energy efficient
lighting of large areas. In the mid 1970s, General Electric and Sylvania both began
experiments on miniaturized metal halide lamps for use in the home. Though Sylvania's
"Mini-Arc" (at left) apparently never made it out of the lab, GE put their "Electronic Halarc" on
the market in 1981.
With a high price and some operating characteristics that residential users found
unacceptable, the lamp failed on the market. GE had shelved several compact
fluorescent designs in favor of the Electronic Halarc, and the lamp's failure temporarily
company in a difficult competitive position.
Compact Fluorescent Lamps (CFL)
Fluorescent lamps represent one of the more efficient ways to make light, and attempts to
make small fluorescent lamps date back to the 1940s. The internal physical
properties make this
more difficult than it sounds, however, and few practical designs emerged from the
1970s. As noted in our invention section, two designs that did appear on the market
were the bent-tube "SL" and "Econ-Nova" designs, from Philips and Westinghouse
respectively, and the bridge-welded "PL" design, also from Philips.
Other manufacturers also put bent-tube designs on the market in the early 1980s.
Interlectric's "U-Lamp" had, like the Philips and Westinghouse lamps, been evaluated in
a late 1970s program sponsored by the US Department of Energy. The Feit Electric Co.
lamp from 1986 was a variation on the bent-tube theme.
These early designs used a magnetic ballast to operate the lamp, but magnetic ballasts
were a major source of energy losses in fluorescent lamps. Advances in solid-state
electronics allowed lamp makers to replace the magnetic ballast with an electronics
package. This led to much more efficient lamps, both because the electronics wasted
less energy than the magnetic ballast and because lamps operated more efficiently on
An early variation in compact fluorescent technology arose from a desire to reuse parts
of the expensive lamp. Generally, the electrodes in a CFL would burn out long before
either a magnetic or an electronic ballast. With one-piece or "integral" designs, this
meant throwing away costly and still usable components. To address this issue, lamp
makers produced multi-piece "modular" designs which allowed the user to replace only
the failed component.
These modular designs typically used tubes with new, plug-style bases so that
consumers could not accidentally couple a tube with an incompatible ballast. The plug-type bases also helped address another problem that became apparent in the late
Many electric utilities, hoping to slow growth in electricity demand, distributed compact
fluorescent lamps to their customers as part of "Demand Side Management" programs.
Sometimes the lamps were given away free, sometimes the utilities used a mail-in
rebate coupon. However, studies found that, for several reasons, many people used the
CFL for a time and then removed it and returned to using an incandescent lamp in that
socketa phenomena called "snap-back."
Plug-type bases encouraged the sale of lighting fixtures with matching sockets. These
"dedicated" fixtures would not accept filament lamps, ensuring that only efficient CFLs
would be used. Of course many people were reluctant to replace entire fixtures, so
designs with conventional screw bases continued to be produced.
A major optical difference exists between CFLs and the filament lamps they are
intended to replace. CFLs emit light evenly along the entire tube surface. Filament
lamps are considered "point sources," meaning that the light emanates from a small
area. Fixtures for incandescent lamps are designed to focus the light from a point
source, not from the broad radiating surface of a CFL, leading to light loss within the
Some designs compensate for this by including a reflector, other designs
simulate the shape of an
incandescent lamp as
seen in this assortment of Duro-Test lamps at left.
However, an advantage of dedicated CFL fixtures is that their optical properties are
designed for CFLs, so little light is lost in the fixture.