Developing an LED Light Bulb

Let’s face it: You’ve heard of Philips. Osram Sylvania. GE. You know they make light bulbs. And while you’re familiar with the incandescents that have been around since the days of Thomas Edison, and the compact fluorescents that are becoming increasingly prevalent as energy conservation becomes de rigueur, you’re probably not as familiar with screwing in an LED lamp, even though LEDs are exceedingly long-lived and energy efficient. (They’re breathtakingly expensive, certainly vis-à-vis your run-of-the-mill incandescent bulb. So far, at least. And when one bulb has a life span of about 1,000 hours and the other 50,000+ hours . . .)

And you’ve probably not heard of PearlLED (pearlled.com; Rohnert Park, CA). Yes, a light bulb manufacturer. Of, yes, LED bulbs. 

But if you had but a few minutes to listen to Tranh Nguyen, PearlLED CEO, you’d get the sense that (1) you’re going to hear about his company and (2) you’re going to want to figure out how to get Pearl-30 light bulbs for your home or office.

Nguyen admits it: “Many companies have LED bulbs out there. And some have bulbs that look similar to the Pearl-30. But they don’t behave the same way. They’re much less luminous.”

Part of the difference is fundamental, he explains. Whereas his competitors started out with reference designs from power supply and chip companies, whereas his competitors often outsource their production to low-wage-rate countries, at PearlLED, “We designed everything from scratch” and the bulb manufacturing is performed in the U.S.

Nguyen has some 30 years’ experience as a power electronics engineer. So he understands the critical power supply issues for LED bulbs. What needs to happen for a bulb is the transformation of AC to DC. As the amount of power increases, the size and weight, as well as cost, tend to increase as well. Another concern for LED bulbs is heat—minimizing it. A vexing issue has been as you increase the size of the power supply, you’re left with decreased space for cooling. So what they did was miniaturize the size of the power supply, and came up with a patented product in doing so.

And as for cooling, the shape of the bulb is like a turbine. Look closer and you’ll notice that each of the fins is bent. The reason: To maximize the surface area, which helps facilitate heat convection, thereby reducing the temperature of the bulb. “Others have shallow fins that don’t work as well,” Nguyen says. “They have to be shallow because the electronics take up the space.”

Then there is the issue of the manufacturing. Nguyen says that he’s performed teardowns of competitive bulbs and discovered things like 12 screws of three different sizes. “The assembler must change screwdrivers three times. And there are 10 different components. The more components and elements there are, the greater possibility of failure.”

The Pearl-30 consists of four basic components: the lens, power adapter, aluminum extrusion, and base. “There are no screws. It is a snap-assembly. The labor content is low, so we don’t have to go offshore,” he says, adding, “If we went offshore, they would copy our know-how.”

Nguyen says that it took about five months to develop the first-generation Pearl-30 bulb and that it went through multiple iterations as they worked to refine it. “I probably spent eight hours a day with Autodesk Inventor,” he says, referencing the 3D mechanical design, product simulation, tooling creation, and communication software suite from Autodesk (usa.autodesk.com). He explains that they developed the entire product and process in software: “We had the whole thing designed on the screen before we manufactured anything. And we made sure that it could be assembled.” He adds, “It saved us from manufacturing mistakes.”

To create the Pearl-30, he says, “We paid attention to a lot of details. And we actually innovate.” He claims that the power supply they developed is so good, “We have something no one can top—including myself.” It’s efficient, small, and low-cost. “If you want to penetrate the consumer market, you have to drive cost down as much as possible.” He says that in order to keep the operating temperature low, not only did they design the fins for the maximum surface area, but they selected 6063 aluminum alloy extrusion rather than a die cast aluminum alloy for the heat sink because not only is the alloy used more conductive, but the extrusion process is less expensive than die casting. “Our optics are totally different from all of the other ones out there.” They use a single-piece, not a lens for each LED. “We have maximum performance and minimum size.”

And on he goes, detailing how they paid attention to each and every element. That has resulted in a building of knowledge of the domain such that, “Now we can develop a new product in probably one week.”

You’re probably going to be hearing about PearlLED.