By Paul Rodriguez, Program Manager, NEMA
When Thomas Edison filed his patent for the incandescent bulb in 1879, his was far from the first or only designer. Similarly, when energy crises demanded the development of the modern compact fluorescent lamp (CFL), it was not the first or only design of its kind. Light-emitting diode (LED) technology got its rise in the semi-conductor industry and is only recently seeing widespread commercial availability. Fueled by energy costs and availability, the lighting industry has been forced to evolve quickly over the last 150 years.
Filaments Yield to Florescent
The first arc lamp was shown to be capable of producing constant light in 1835. It took more than 40 years for Thomas Edison to file a patent on the incandescent lamp. In the interim, scientists were feverishly trying to make filament bulbs cost-effective and longer-lasting.
The main focus of experiments during this time was the makeup of the filament within the bulbs. Incandescent bulbs work by heating the filament with an electrical current. When the filament gets hot enough, it produces the light you see. By varying the makeup of this filament, scientists found different colors, intensities, and lifespans that were significantly dependent on the type of filament used.
Early in the life of the filament bulb, the filament was made of carbon. Mr. Edison even used a bamboo filament to achieve a substantial increase in the lamp’s lifetime. Ultimately, the industry saw huge gains in efficiency and quality with the use of modern tungsten filament in 1904. Though Mr. Edison might not have built the first light-producing source, the steps that he made to improve the bulb were momentous. From the Edison screw base for lamps to better manufacturing processes, Mr. Edison was truly the father of the incandescent bulb.
Though incandescent bulbs were novel and eventually found their way into the commercial market, inefficiency and rising energy costs soon led to the development and commercialization of the modern fluorescent bulb.
Fluorescent bulbs found their start in the invention of discharge lamps (lamps that work by passing an electrical current through a gaseous chamber).
Sir Humphry Davy demonstrated the phenomenon of electric arc in 1802. Discharge lamps were being studied as early as the late 19th century, but they did not gain popularity until scientists found that the introduction of different gases into the tubes could create different light.
The most notable of these gases is mercury, which was found to create a blueish-green light. Later, scientists found that they could use phosphors to manipulate the color of the light coming from the tube. These lamps were now giving off pleasant light colors while using a quarter of the light of incandescent bulbs. They also lasted ten times longer than their incandescent predecessors.
Ceding Future to LEDs
In recent years, fluorescent lighting has grudgingly yielded ground to LED technology.
LEDs existed as early as the 1960s but were used in very limited applications. After the invention of blue LEDs in the 1990s, it was a short step to more commercial applications. Scientists again used phosphors to change the light color to something more consumer-friendly. A global focus on energy efficiency and conservation has put LEDs firmly in the lighting arena. LEDs account for a sixth of the energy used for lighting in the U.S. and are rapidly expanding into commercial and residential use.
As we reach new levels of energy efficiency with modern bulbs, scientists are hard-pressed to achieve any more efficiency from the bulbs themselves. Using high-performance bulbs such as modern LEDs in tandem with controls such as occupancy and photo sensors compounds the benefits from both.
We can expect to see the next big innovation in lighting come from the interfacing of these lamps and controls.
This piece was originally published in the February 2016 issue of ei, the magazine of the electroindustry.