How LED Light Bulbs Are Made?

To understand just how revolutionary LED light bulbs are as well as why they are still expensive, it is instructive to look at how they are manufactured and to compare this to the manufacture of incandescent light bulbs. This article explores how incandescent light bulbs are made and then contrasts that process with a description of the typical manufacturing process for LED light bulbs. So, let's begin by taking a look at how traditional incandescent Light Bulbs are manufactured. You will find that this is a classic example of an automated industrial process refined over a century of experience. LED light bulbs are built around solid-state semiconductor devices, so the manufacturing process most closely resembles that used to make electronic products like PC motherboards.

One hundred-and-thirty years ago, Thomas Edison completed the first successful sustained test of the incandescent light bulb. With some incremental improvements along the way, Edison's basic technology has lit the world ever since. This is about to change. We are on the cusp of a semiconductor-based lighting revolution that will ultimately replace Edison's bulbs with a far more energy-efficient lighting solution. Solid state LED lighting will eventually replace almost all of the hundreds of billions of incandescent and fluorescent lights in use around the world today. In fact, as a step along this path, President Obama last June unveiled new, stricter lighting standards that will support the phasing out of incandescent bulbs (which already are banned in parts of Europe).

While individual incandescent LED Light Bulb types differ in size and wattage, all of them have the three basic parts: the filament, the bulb, and the base. The filament is made of tungsten. While very fragile, tungsten filaments can withstand temperatures of 4,500 degrees Fahrenheit and above. The connecting or lead-in wires are typically made of nickel-iron wire. This wire is dipped into a borax solution to make the wire more adherent to the glass. The bulb itself is made of glass and contains a mixture of gases, usually argon and nitrogen, which increase the life of the filament. Air is pumped out of the bulb and replaced with gases. A standard base holds the entire assembly in place. The base is known as the "Edison screw base." Aluminum is used on the outside and glass is used to insulate the inside of the base.

Originally produced by hand, bulb manufacturing is now almost entirely automated. First, the filament is manufactured using a process known as drawing, in which tungsten is mixed with a binder material and pulled through a die (a shaped orifice) into a fine wire. Next, the wire is wound around a metal bar called a mandrel in order to mold it into its proper coiled shape, and then it is heated in a process known as annealing, softening the wire and making its structure more uniform. The mandrel is then dissolved in acid. Second, the coiled filament is attached to the lead-in wires. The lead-in wires have hooks at their ends which are either pressed over the end of the filament or, in larger bulbs, spot-welded.