When placed in a conventional table lamp most LED light bulbs, including this LG bulb, have a tendency to illuminate upwards. This is because of the horizontal placement of the LED emitters inside. The Philips bulbs use three vertically oriented LED panels to alleviate this concern. However, in an over the shoulder reading lamp or a task lamp, the bulb illuminates uniformly and does not throw any heat on the illuminated target.
The LG light bulb illuminates mostly upwards because of the horizontal
placement of the LED panel inside the bulb (click on image to enlarge).
The design of table lamps is meant to accommodate the Edison light bulb, which emits light in all directions. The spindle allows the electrical cord to reach the bulb and the lamp shade serves as a diffuser. The shade, being open top and bottom, allows the natural convection to take away the unwanted heat. It also enables easy replacement of the short-lived bulb. The electric table lamp has evolved over more than a century to accommodate the light bulb and is very different from its precursor luminaire, the oil lamp.
The very first electric lamps were not necessarily very effective or very popular, yet their advantages prevailed and the use of oil lamps waned. Over time, and probably rather rapidly, lamps will evolve to adapt to the peculiarities of the LED sources. When LED light sources achieve lifetimes in decades, replacing them will no longer be a concern and luminaires will take on various forms and shapes. Meanwhile, forcing LEDs to assume the Edison format is akin to forcing a square peg into a round hole.
Nevertheless, Strategies Unlimited predicts that "the global market for replacements for legacy lighting sources will grow from $2.2 billion in 2011 to $3.7 billion in 2016." Indeed, LED light bulbs provide very pleasant illumination, much more agreeable than compact fluorescent bulbs, and they will be adopted eagerly. They outlast CFLs, contain no mercury, and are instant-on. One annoying trait of CFLs is that they take a relatively long time to reach their maximum level of illumination.
LED light bulbs are complex electronic devices. The LEDs themselves are semiconductor diodes, wanting a low voltage DC supply, typically around 3 volts. Common household supply is 110V or 220V AC depending on geographic location. The LG bulb is not dimmable. More expensive models are dimmable, although newer types of dimmers may be needed. Like CFL bulbs, LED bulbs have a small circuit board stuffed inside the neck.
Watching this technology improve is fascinating. I find the attempt to make the bulb look very similar to the old incandescent bulb interesting. I'm not sure how much that helps sell the new bulb ( although we do, of course, need a compatible base ), but hopefully we'll see prices drop further and then see more adoption by consumers.
The 60W LED bulb has officially arrived. It's about time. I immediately ran out and got 3 of the Philips dimmables, even though they were still $25 each, just as a show of appreciation as an early adopter for this effort. The bulbs are fantastic, and kinda look like they came from the future, but I'll wait until the prices re-enter the atmosphere before I get any more.
$25 each if it lasts 3-5 times more than CFL, I think it is a good deal.
If heat is an issue, which piece will go away first, the power electronics or the LED? I believe it is the power electronics, isn't it?
I think that which fails first depends on the design margins. One might suspect the power electronics to be the weak link. Consider that the front end of these PCBs is an AC-DC power supply with the usual electrolytic capacitors. My bet would be that those caps are the first thing to go.
LED light bulbs are too recent to have much data on failure modes. Electrolytic caps are indeed vulnerable to heat. This light bulb has a nice space between the back of the LED emitters and the circuit card. That should help. Most failures I have seen in CFLs circuit cards were due to sub-standard assembly, not design.
This is great. My only issue I have with the article is the notion, which I have seen expressed many times, that direct replacement of the light bulb should not be an important feature of these new LED "bulbs."
And while light bulbs did not directly replace candles or kerosene lamps nets (or whatever they were called), in the same sort of luminary, the electric lamps did closely emulate their forebears. And still do.
I've seen LED bulbs that do not arrange the LEDs in a plane, or at least they don't seem to. I have an LED candelabra based, for chandelier use, that emits light in all directions, every bit as much as a light bulb does, every bit as much as candles used to do in chandeliers.
Not saying that new types of lamps, with permanently installed LEDs, won't ALSO exist. But let's not be so happy to turn this into a racket for lamp makers, eh? Besides which, LED electronics may fail, for whatever reason, and LEDs tend to dim with use. So easy replacement will continue to be a good idea. For the customer, at least.