The Producting Process Of LEDs Bulbs—Part 1

LEDs bulbs are built around solid-state semiconductor devices, so the manufacturing process most closely resembles that used to make electronic products like PC mother boards. A light-emitting diode (LED) is a solid state electrical circuit that generates light by the movement of electrons in a semiconductor material. LED technology has been around since the late 1960s, but for the first 40 years LEDs were primarily used in electronics devices to replace miniature light bulbs. Within the last decade, advances in the technology finally boosted light output high enough for LEDs to begin to seriously compete with incandescent and fluorescent light bulbs. As with many technologies, as the cost of production falls each successive LED generation also improves in light quality, output per watt, and heat management. The computer industry is well suited to manufacture LED lighting. The process isn't a whole lot different than making a computer motherboard. The companies making the LEDs themselves are generally not in the lighting business, or it is a minor part of their business. They tend to be semiconductor houses that are happy cranking out their product, which is why prices on high-output LEDs has fallen so much in the last 15 years. LED bulbs themselves are expensive in part because it takes a number of LEDs to get wide-area illumination instead of a narrow beam, and the assembly cost adds to the overall price. In addition, assemblies consisting of arrays of LEDs create more opportunities for product defects. An LED light consists of four essential components: an LED circuit board, a heatsink, a power supply, and a shell. The lights start out as bare printed circuit boards (PCB) and high luminance LED elements arrive from separate factories which specialize in making those components. LED elements themselves create a bit of heat, so the PCB used in lighting fixtures is special. Instead of the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is laid out on a thin sheet of aluminum which acts as a heatsink. The aluminum PCB used in LEDs bulbs is coated with a non-conducting material and conductive copper trace lines to form the circuit board. Solder paste is then applied in the right places and then Surface Mount Technology (SMT) machines place the tiny LED elements, driver ICs, and other components onto the board at ultra high speeds. The round shape of a traditional light bulb means that most LED printed circuit boards are circular, so for ease of handling several of the smaller circular PCBs are combined into one larger rectangular PCB that automated SMT machinery can handle. Think of it like a cupcake tray moving from one machine to the next along a conveyor belt, then at the end the individual cupcakes are snapped free from the tray.